What is the reason for the punch falling off in the processing of automobile stamping parts?

In the process of automobile stamping, sometimes the die punch will suddenly fall off, so what causes the punch to fall off? In fact, the main reason for the analysis of punch dropout is that the punch is not strong. What is the reason why the punch is not fixed firmly? The main reasons are as follows:

1. For the fixed structure of the punch that is pressed into the interference, because the required amount of interference cannot be met during the manufacturing process, the method of “twisting and squeezing” is used to remedy it, so that the punch is easy to loosen.

2. If the punch is not fixed by steps or fasteners, punch thick, hard or viscous materials. If the gap between the stripper hole and the punch is too large, the discharge force will increase, causing the punch to pull out.

3. The rigidity of the punch or die frame is poor, and the punch is elastically deformed during punching, causing the punch to collide or get stuck with the stripper, increasing the unloading force and easily pulling out the punch.

4. The punch and die gap is too small, the working surface is rough, or the gap is sideways, which will increase the discharge force during punching and cause the punch to pull out.

5. When the punch is fixed with a low melting point alloy, there is no groove on the assembly side of the punch and the assembly hole of the punch fixing plate, which makes it easy to pull out the punch.

1. Why does gnawing occur during the processing of automobile stamping parts? How should it be prevented?

A bite is a touch blade. During the blanking process, a certain gap should be maintained between the die blades, and they should not collide with each other. There are four reasons for the collision of the blades.

1. Design: In terms of equipment, the punch is incorrect. If the punch is fixed by chiseling, it may cause the punch to loosen. Casting of low melting point alloys can also lead to punch loosening. The punching pressure is large, the punch root does not use a hard backing plate, and the lateral force of the punch is too large, which will cause the punch to loosen.

2. Molding: convex, concave mold or guide parts are not installed vertically.

3. The assembly of the upper and lower formwork, the fixed plate and the convex and concave formwork is not parallel.

The blanking gap is not uniform.

4. The installation of the punch does not meet the design requirements.

Second, the use of molds.

1. Repeated punching or stack punching, that is, stacking two or more blanks in a place where the blanks do not move for punching.

2. The scraps or blanking parts left on the mold are not removed in time.

Third, mold maintenance problems.

1. The wear of the mold parts is large, and the fitting clearance caused by the wear of the guide parts is too large, which cannot be repaired in time.

2. The mold maintenance assembly is loose.

In order to avoid die gnawing, a die with a guide should be used as much as possible, especially for a die with a small blanking gap. The fixing method of the punch should be carefully considered, and the manufacturing of the mold should be firm and reliable. The composite punching die should pay special attention to operate in strict accordance with the punching operation rules, clean the surface of the die in time, and avoid repeated punching and stacking. Strengthen the maintenance and management of molds to ensure that the molds are in good condition. Hope it helps readers.

How to avoid damage in metal stamping die processing?

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1. How to avoid damage as follows:

1. The sliding hinge cannot be made of aluminum alloy material, but stainless steel material should be used.

2. Sliding windows with a width greater than 1 meter, or doors and windows with double-glazed glass, should be equipped with double pulleys or use movable pulleys.

3. Hardware accessories should be Z-terminals, door and window locks. Handles, etc. should be installed behind the window and door frame to ensure accurate position and flexible switching.

4. When using fastening screws to install hardware, there must be a metal backing plate, and the thickness of the backing plate is at least twice the pitch of the fasteners. It cannot be used to fix plastic profiles, and non-metallic linings cannot be used.

5. The type, specification and performance of the hardware accessories used should conform to the current national standards and relevant boundaries, and should be used in conjunction with the selected plastic steel doors and windows.

6. Pay attention to maintenance after installation to avoid corrosion. When used every day, lightly close and lightly open to avoid damage caused by hard opening of the hard tube.

How to inspect metal stampings? Rockwell hardness tester is used for hardness test of metal stamping parts. Such as: small, irregularly shaped stamping parts, can be used to detect small planes, can not be used for ordinary desktop Rockwell hardness tester.

PHP series Rockwell hardness tester is especially suitable for hardness testing of such stamping parts. Aluminum alloy stamping parts are common parts in the fields of metal processing and mechanical manufacturing. The processing of stamping parts is a processing method in which metal sheets and strips are separated or formed using molds. It has a wide range of applications.

The main purpose of the hardness inspection of blanking parts is to judge whether the annealing degree of the metal plate is suitable for the processing of stamping parts in the future. In the processing of different types of stamping parts, there are requirements for plates with different hardness levels. Webster hardness tester can be used to test the processing of stamping parts. When the data exceeds 13mm, it can be replaced by a barcol hardness tester, and a barcol hardness tester can be used for pure aluminum or low-hardness aluminum alloy sheets.

As far as the stamping industry is concerned, stamping is sometimes referred to as sheet metal forming, but it is slightly different. What we call sheet molding is a forming method of plasticizing raw materials such as thin plates, collectively referred to as sheet forming. In this case, the deformation in the direction of the thick plate is generally ignored.

Second, optimize the planning method of metal stamping parts.

The reasonable planning of the mold is the basis for improving the durability of the mold. In order to improve the durability of metal stamping dies, unreasonable factors in product forming should be fed back in time during die planning. If you plan to punch a small hole metal mold, the method of adding a guide sleeve should be used to strengthen the strength of the small hole mold punching needle. Also, the guide needle should be as short as possible. Decreased length equals increased strength.

3. Appropriate heat treatment of metal blanking parts.

High-quality metal stamping dies and the selection of plates should be properly heat treated to improve the durability of metal stamping dies. Such as quenching, vacuum heat treatment, etc.

Fourth, the rational use of metal stamping dies can ensure processing accuracy.

In terms of hardware mold life, mold accuracy has a great influence on mold life. Before making the mold, the mold must be installed. Commissioning the mold requires locating all the holes and installing the mold prior to production. When the mold is installed, the straightness of the support surface of the mold and the fixed plate, and the uniformity of the distance between the hardware mold and the guide sleeve have strict requirements on the guiding accuracy of the guide post. The higher the manufacturing and installation accuracy, the more accurate the machined parts will be, and the higher the durability of the metal mold will be.

Fifth, choose the correct amount of punching.

In order to improve the durability of the hardware blanking die, the blanking die with high precision and high rigidity should be selected. For stamping more than 30%, it is better to use the servo to control the punch. The servo is equivalent to a transformer, with constant current and stable voltage, which not only protects the durability of the machine tool, but also improves the service life of the mold.

6. Reasonable use and protection of molds.

In order to improve the durability of metal stamping dies, operators must regularly protect and maintain the dies under reasonable conditions of use. It is best to maintain and repair the metal stamping dies every day, which can effectively avoid the appearance of metal stamping dies.

According to the above related content of metal stamping die processing, metal stamping parts are light in weight, satisfactory in strength and rigidity, and can be processed into parts of various shapes and sizes according to different uses and materials, and have a wider range of applications. Hope the above content can be helpful to readers.

What are the manufacturing materials of stamping molds?

Among the four major processes, stamping is very important. In the stamping process, the quality of the stamping die is a very important process. It often stops production due to the failure of the blanking die, which affects the quality of the blanking parts and the production cycle. In addition to the process of stamping die production, the material is also a very important part, and the stamping die material is the key to prolonging its service life. The following is the editor of Zhejiang Baifudu Electromechanical to introduce some common stamping die manufacturing materials. .

The materials for producing stamping parts include high-speed steel, carbon tool steel, alloy tool steel, cemented carbide, steel-bonded cemented carbide, zinc-based alloy, low melting point alloy, aluminum bronze, polymer materials, etc. At present, many materials are used for stamping dies. for steel.

1. Carbon tool steel

Carbon tool steels such as T8A and T10A are used for stamping dies, which are characterized by good workability and low price; but poor hardenability and red hardness, large heat treatment deformation, and low bearing capacity.

2. Low alloy steel

Low-alloy steel is based on carbon tool steel, adding an appropriate amount of alloying elements. Compared with carbon tool steel, the quenching deformation tendency is small, the hardenability is good, and the wear resistance after quenching is good. The low alloy steel used for stamping parts is CrWMn.9Mn2V. 7CrSiMnMoV (code CH-1). 6CrNiSiMnMoV (code GD), etc.

3. High carbon-high chromium tool steel

Cr12 and Cr12MoV. Cr12Mo1V1 (code D2) is a common high carbon and high chromium tool steel with good hardening properties and minimal heat treatment deformation. They are highly wear-resistant, slightly deformed die steels, second only to high-speed steels in bearing capacity. But the carbide segregation is serious and must be upsetting repeatedly (axial upsetting). Through forging, the non-uniformity of carbides can be reduced and the service performance can be improved.

4. Medium chromium high carbon tool steel.

High-carbon medium-chromium tool steels are mainly Cr4W2MoV, Cr6WV ​​and other Cr5MoV, etc., which have low chromium content, uniform carbide distribution, small heat treatment deformation, good hardenability, and good processing dimensional stability. The results show that the performance is improved compared with the high carbon and high chromium steel with a larger degree of carbide segregation.

5. High-speed steel

Among high-speed steels, it has the highest hardness, wear resistance, high compressive strength and high bearing capacity. W18Cr4V (code 8-4-1), tungsten W6Mo5Cr4V2 (code 6-5-4-2), Japanese trademark SKH51, American brand M2) and 6W6Mo5Cr4V (code 6W6, also known as low carbon M2) for toughness enhancement .

6. Basic steel

Adding a small amount of other elements to the basic composition of high-speed steel and appropriately increasing the carbon content can improve the performance of the steel. Such steels are collectively referred to as base steels. It not only has high wear resistance and hardness, but also has better fatigue strength and toughness than high-speed steel. It is a high toughness cold work die steel with lower material cost than high speed steel. The basic steels commonly used in stamping dies are 6Cr4W3Mo2VNb (code 65Nb), 7Cr7Mo2V2Si (code LD), 5Cr4Mo3SiMnVal (code 012Al), etc.

7. Carbide and steel bonded cemented carbide.

Carbonization has higher hardness and wear resistance, but poor bending strength and toughness. Tungsten-cobalt alloys are used as cemented carbides for molds. For molds with low impact and high wear resistance, cemented carbide with low cobalt content can be selected. For impact dies, carbides with high cobalt content can be used.

Steel-bonded cemented carbide is sintered by powder metallurgy with a small amount of alloying element powder (such as chromium, molybdenum, tungsten, vanadium, etc.) as the binder and titanium carbide or tungsten carbide as the hard phase. Steel-bonded cemented carbide is based on steel, which overcomes the disadvantages of poor toughness and difficult processing of cemented carbide, and can be cut, welded, forged and heat treated. Steel-bonded cemented carbides contain more carbides. The hardness and wear resistance of steel-bonded cemented carbide after quenching are poor, but the hardness is high, up to 68-73HRC.

The above is the content related to stamping die manufacturing materials. The manufacturing cost of stamping dies is high, and the general die cost accounts for 1/4-1/5 of the total cost of stamping parts. The cost of a trimming is more than 70% of the original mold cost, or the mold life is close. If the mold repair process is too complicated, the mold repair cost is too high, and the difficulty is high, the maintenance cycle will be too long, which will seriously affect the normal production of stamping parts. Hope the above content can be helpful to readers.

How to control the deformation of precision gear stamping

1. The main factors affecting the heat treatment deformation of gears

1. The influence of material metallurgical factors on gear deformation: the higher the hardenability of steel, the greater the deformation. When the center hardness is greater than 40HRC, the amount of deformation increases significantly. Deformation is more stable, provided by steel mills, deformation is low, stable, steel. When the content of a/n is controlled between 1 and 2.5, the hardenability zone can be reduced and the amount of deformation can be reduced.

2. The effect of preliminary heat treatment on gear deformation: the normalizing hardness is too high, and a large amount of sorbite will increase the deformation of the inner hole, so the forgings should be treated with temperature-controlled normalizing or isothermal annealing.

3. Influence of carburizing process on deformation: uniformity of temperature. The uniformity of the carbon layer and the uniform temperature of the cooling system medium will affect the analysis of the deformation of the gear structure. At the same time, the carburizing temperature is required to be higher and higher, the thicker the carburized layer, the lower the oil temperature, and the larger the gear deformation.

4. Influence of quenching on deformation: Quenching and cooling behavior is an important factor affecting the deformation of gears, and the deformation of hot oil quenching is smaller than that of cold oil quenching. The cooling ability of the oil is also key to deformation. The mixing mode and strength are affected by deformation, quenching pressure quenching plate gears, according to the deformation of various gears. By adjusting the parameters of the punching machine, reducing the deformation, adjusting the pressure of the inner and outer die and the expansion pellet, adjusting the size of the oil injection of each section and the size of the top table, the deformation is controlled.

5. Clamping method and fixture: The purpose is to make the workpiece heat and cool evenly, and the carburized layer of each part of the workpiece is uniform to reduce uneven thermal stress and structural stress, thereby reducing deformation. The clamping mode can be changed. The disc part is perpendicular to the oil surface, and the shaft part is installed vertically, using compensation washers, support washers and superimposed washers. The splined hole parts can be carburized mandrels.

There are many factors that affect the deformation of carburizing heat treatment, which may be the result of the comprehensive influence of various reasons. Only by controlling various factors, the deformation can be controlled to a lesser extent. Controlling gear deformation is also an important problem to be solved in the whole process of gear manufacturing.

2. Specific control measures for gear heat treatment deformation

Through the above analysis, it is known that there are many factors that affect the deformation of gears during heat treatment, and they exist in each link. In order to control the deformation of gears during heat treatment, relevant technical personnel can refer to specific control measures to improve the quality of gears.

1. Scientific selection of gear material

The hardenability of gear raw materials directly affects the heat treatment deformation of gears. It is necessary to scientifically select the raw materials for making gears. Different materials have different hardenability. , Compared with other materials, the hardenability of steel is better. At the same time, the precision of the gear will also affect the hardenability of the raw material. For example, the raw material of the gear in my country is mainly 20Cr Mn Ti steel. This kind of steel has uneven crystals and is prone to heat treatment deformation. In addition, considering the overall cost, it is necessary to choose suitable machining equipment.

2. Reasonable gear design

Relevant designers should fully consider the various reasons that cause the deformation of the gear heat treatment process, and design the gear shape scientifically and rationally without changing the original performance. Simple and direct is the best, so as to reduce the deformation problem caused by uneven force.

3. Select the appropriate heat treatment process

In the process of heat treatment of gears, quenching oil should be selected as the quenching medium. Hot oil quenching has smaller deformation than cold oil quenching. The cooling capacity and stirring method of the oil are also important factors affecting the deformation. At the same time, additives should be properly applied to improve the hardness of gear parts. , to ensure the quality of the gear.

4. Optimize the charging method

In order to make the gear parts heat evenly during the heating process, the charging method can be optimized. The disc parts are placed vertically with the oil surface, and the shaft parts are installed vertically. At the same time, compensation washers can be used to reduce gears caused by uneven heat. Deformation occurs.

5. Preheating

After the gear is forged, there will also be uneven heating in the heat treatment process due to uncontrollable stress. Preheating can effectively prevent this from happening. Preheating after forging can improve the quality of gear raw materials. The organizational structure can effectively prevent the problem of deformation due to stress redistribution.

6. Improve the quality of machining

In the selection of mechanical equipment, it is necessary to choose high-quality mechanical equipment. Considering a series of factors that affect the deformation of the gear heat treatment, the technicians can summarize the reasons for the deformation of the gear, and prepare a preventive plan in advance in the subsequent heat treatment process of the gear, which can effectively prevent the occurrence of deformation. In addition, for gears with special materials and strange shapes, secondary heat treatment is required to be safe.

From the above analysis, it is known that there are many factors that affect the deformation of gear heat treatment. In order to

It can effectively prevent the occurrence of gear heat treatment deformation, not only to scientifically select the material of cast gears and reasonable gear design, but also to make full use of thermal processing technology to comprehensively improve the quality of machining, thereby effectively reducing the probability of gear heat treatment deformation. , to ensure the service life of the gear.

First, we can see the information from the situation of the waste.

First, we can see the information from the situation of the waste.

The scrap is essentially the inverse of the formed hole. That is, the same part in the opposite position. By carefully inspecting the scrap, you can infer whether the upper and lower die gaps are accurate. If the gap is too large, the scrap will exhibit rough, undulating fracture surfaces and a narrow bright band area. The larger the gap, the greater the angle the fracture surface makes with the bright band area. If the gap is too small, the scrap will exhibit a small angled fracture surface and a wide bright band area.

Excessive clearance creates holes with large curls and edge tearing, leaving the cut face slightly protruding with a thin edge. A gap that is too small results in a slight hemming of the tape and a large angular tear, resulting in the cut plane being more or less perpendicular to the surface of the material.

An ideal scrap should have a reasonable collapse angle and a uniform bright band. This keeps the punching force low and creates a clean round hole with very few burrs. From this point of view, increasing the die life by increasing the clearance is at the expense of finished hole quality.

Second, the choice of mold clearance

The clearance of the die is related to the type and thickness of the material being punched. Unreasonable clearance can cause the following problems:

(1) If the gap is too large, the burr of the punched workpiece is relatively large, and the quality of the punched product is poor. If the clearance is too small, although the quality of the punched product is good, the wear of the die is quite serious, which greatly reduces the service life of the die and easily causes the punch to break.

(2) If the gap is too large or too small, it is easy to cause adhesion on the punch material, which will cause the material to be tapered during punching. If the gap is too small, it is easy to form a vacuum between the bottom surface of the punch and the sheet, and the waste will bounce back.

(3) Reasonable clearance can prolong the life of the mold, the discharge effect is good, the burrs and flanging are reduced, the plate is kept clean, the hole diameter is consistent and the plate will not be scratched, the number of sharpening is reduced, the plate is kept straight, and the punching positioning is accurate.

3. How to improve the service life of the mold

For users, improving the service life of the mold can greatly reduce the stamping cost. The reasons that affect the service life of the mold are as follows:

1. The type and thickness of the material.

2. Whether to choose a reasonable die gap.

3. The internal structure of the mold.

4. Whether the material is well lubricated during stamping.

5. Whether the mold has undergone special surface treatment.

6. Such as titanium plating, titanium carbonitride.

7. The neutrality of the upper and lower turrets.

8. Adjust the rational use of gaskets.

9. Whether the oblique edge mold is used properly.

10. Whether the die base of the machine tool has been worn.

Fourth, the problems that should be paid attention to when punching special size holes

(1) Please use a special punch for punching in the range of φ0.8-φ1.6 with the minimum hole diameter.

(2) When punching a thick plate, use a die one size larger than the hole diameter. Note: At this time, if a normal size die is used, the punch thread will be damaged.

(3) For the cutting edge of the punch, the ratio of the minimum width to the length should generally not be less than 1:10.

(4) The relationship between the minimum size of the punch edge part and the plate thickness. It is recommended that the smaller size of the punch edge part be 2 times the thickness of the plate.

5. Sharpening of the mold

1. The importance of mold sharpening

Regular sharpening of the die is the guarantee of consistent punching quality. Regular sharpening of the mold can not only improve the service life of the mold but also improve the service life of the machine. It is necessary to master the correct sharpening timing.

2. The specific characteristics of the mold that needs to be sharpened

For die sharpening, there is no strict number of blows to determine if sharpening is required. mainly depends on

The sharpness of the cutting edge. It is mainly determined by the following three factors:

(1) Check the fillet of the cutting edge. If the fillet radius reaches R0.1 mm (the maximum R value must not exceed 0.25 mm), it needs to be sharpened.

(2) Check the punching quality, is there a large burr?

(3) Judge whether sharpening is required by the noise of machine stamping. If the noise is abnormal when the same pair of die is punched, it means that the punch is dull and needs to be sharpened.

Note: If the edge of the cutting edge becomes rounded or the rear of the cutting edge is rough, sharpening should also be considered.

3. The method of sharpening

There are many ways to sharpen the mold, which can be realized by a special sharpening machine or a surface grinder. The frequency of punch and die sharpening is generally 4:1. Please adjust the height of the die after sharpening.

(1) Harm of incorrect sharpening method: Incorrect sharpening will aggravate the rapid destruction of the die edge, resulting in a greatly reduced number of blows per sharpening.

(2) The benefits of the correct sharpening method: regularly sharpening the mold, the quality and precision of the punching can be kept stable. The cutting edge of the mold is damaged slowly and has a longer life.

4. Sharpening rules

The following factors should be considered when sharpening the mold:

(1) The fillet of the cutting edge depends on the sharpness of the cutting edge in the case of R0.1-0.25 mm.

(2) The surface of the grinding wheel should be cleaned.

(3) It is recommended to use a loose, coarse-grained, soft grinding wheel. Such as WA46KV

(4) The amount of grinding each time (the amount of knife cutting) should not exceed 0.013 mm. Excessive grinding will cause the surface of the mold to overheat, which is equivalent to annealing treatment, and the mold becomes soft, which greatly reduces the life of the mold.

(5) Sufficient coolant must be added during sharpening.

(6) When grinding, the punch and the lower die should be fixed smoothly, and a special fixture should be used.

(7) The sharpening amount of the mold is certain. If this value is reached, the punch will be scrapped. If you continue to use it, it is easy to cause damage to the mold and the machine, which is not worth the loss.

(8) After sharpening, the edge should be treated with whetstone to remove excessively sharp ridges.

(9) After sharpening, it should be cleaned, demagnetized and oiled.

Note: The amount of die sharpening mainly depends on the thickness of the punched sheet.

Six, the punch should pay attention before using

1. Storage

(1) Wipe the inside and outside of the upper die sleeve with a clean rag.

(2) Be careful not to scratch or dent the surface during storage.

(3) Oiled to prevent rust.

2. Preparation before use

(1) Thoroughly clean the upper die sleeve before use.

(2) Check the surface for scratches and dents. If so, remove with whetstone.

(3) Oiling inside and out.

3. Matters needing attention when installing the punch on the upper die sleeve

(1) Clean the punch and oil its shank.

(2) Insert the punch into the bottom of the upper die sleeve on the large-station die without using force. Nylon hammers cannot be used. During installation, the punch cannot be fixed by tightening the bolts on the upper die sleeve, and the bolts can only be tightened after the punch is positioned correctly. Zhengquan Technology WeChat content is really good, it is worth paying attention to!

4. Install the upper die combination into the turret

If you want to prolong the service life of the mold, the gap between the outer diameter of the upper die sleeve and the turret hole should be as small as possible. So please perform the following procedures carefully.

(1) Clean and oil the keyway and inner diameter of the turret hole.

(2) Adjust the keyway of the upper die guide sleeve to match the key of the turret hole.

(3) Insert the upper die sleeve straight into the tower hole, being careful not to have any inclination. The upper die guide should slide under its own weight into the turret hole.

(4) If the upper die sleeve is inclined to one side, use a soft material tool such as a nylon hammer to tap it gently and repeatedly until the upper die guide sleeve slides into the correct position by its own weight.

Note: Do not use force on the outer diameter of the upper die guide sleeve, but only on the top of the punch. Do not tap the top of the upper die sleeve, so as not to damage the turret hole and shorten the service life of individual stations.

Seven, mold maintenance

If the punch is caught by the material and cannot be taken out, please check the items listed below.

1. Re-sharpening of punch and lower die. A mold with a sharp edge can process a beautiful cut surface. If the edge is blunt, additional punching force is required, and the workpiece has a rough section, which produces great resistance, causing the punch to be bitten by the material.

2. The gap of the mold. If the gap of the die is not properly selected relative to the thickness of the plate, the punch needs a large demoulding force when it is separated from the material. If this is the reason the punch is bitten by the material, please replace the lower die with a reasonable clearance. Zhengquan Technology WeChat content is really good, worthy of attention!!

3. The state of the processed material. When the material is dirty or dirty, the dirt adheres to the die and the punch is caught by the material and cannot be processed.

4. Deformed materials. The warped material clamps the punch after the hole is punched, causing the punch to bite. For warped materials, please flatten them before processing.

5. Excessive use of springs. will fatigue the spring. Always pay attention to check the performance of the spring.

Eight, oiling

The amount of oil and the number of oil injections depend on the conditions of the material being processed. For cold-rolled steel plates, corrosion-resistant steel plates and other rust-free and non-scaling materials, oil should be injected into the mold. The oil injection points are the guide bush, the oil injection port, the contact surface between the cutter body and the guide bush, and the lower die. Use light motor oil.

For materials with rust and scale, the rust powder will be sucked between the punch and the guide sleeve during processing, resulting in dirt, so that the punch cannot slide freely in the guide sleeve. In this case, if oil is applied, it will make the rust easier Therefore, when flushing this material, on the contrary, wipe the oil clean, decompose it once a month, use gasoline (diesel) oil to remove the dirt on the punch and the lower die, and wipe it before reassembly. This ensures that the mold has good lubricating properties.

Nine, the problems and solutions that often occur during the use of the mold

Problem 1. The plate comes out of the clamping jaw

Reason: incomplete unloading of the mold

Solution:

1. Use a taper punch

2. Apply lubricating fluid on the plate

3. Adopt heavy duty mould

Problem 2, the mold is seriously worn

Reason: unreasonable die gap (small)

Solution: increase the mold gap

Reason: The upper and lower die bases are not aligned

Solution:

1. Work station adjustment, centering of upper and lower molds

2. Turret level adjustment

Reason: The worn mold guide components and the inserts of the turret were not replaced in time

Solution: replace

Reason: Punch overheating

Solution:

1. Add lubricating fluid to the sheet

2. Ensure lubrication between punch and lower die

3. Use multiple sets of molds of the same size in the same program

Reason: improper sharpening method, resulting in annealing of the mold, resulting in increased wear

Solution:

1. Use soft abrasive grinding wheel

2. Clean the grinding wheel frequently

3. Small amount of knife

4. Sufficient coolant

Reason: small step

Solution:

1. Increase the step distance

2. Adopt bridge nibbling

Problem 3. Punch material and punch sticking

Reason: unreasonable die gap (small)

Solution: increase the mold gap

Reason: Passivation of punch edge

Solution: sharpen in time

Reason: poor lubrication

Solution: Improve lubrication conditions

Problem 4. Scrap rebound

Reason: die problem

Solution:

1. Using bulletproof material to lower the mold

2. For small diameter holes, the clearance is reduced by 10%

3. When the diameter is greater than 50.00 mm, the gap is enlarged

4. Increase scratches on the edge side of the die

Reason: punch

Solution:

1. Increase the depth of the mold

2. Install the unloading polyurethane ejector bar

3. Adopt oblique cutting edge

Problem 5. Difficulty in unloading

Reason: unreasonable die gap (small)

Solution: increase the mold gap

Reason: punch wear

Solution: sharpen in time

Cause: Spring fatigue

Solution: replace the spring

Reason: Punch sticking

Solution: Remove the sticking

Question six, rush

What are the advantages of precision metal stamping parts processing?

1. What is precision metal stamping?

Precision metal stamping is a high-volume metalworking process that uses stamping tools to press material into the desired shape to create sheet metal parts. This is done according to a pattern where each part is removed from the motherboard after stamping.

Precision metal stamping enables manufacturers to create parts that require undercuts, multiple features, or frangible walls for assembly. It uses high-pressure equipment to press the metal plate into the mold, so the shape of the product has geometric accuracy and good surface finish.

Second, the advantages of precision metal stamping

Precision metal stamping offers manufacturers and end users a variety of advantages. These include:

1. Mass production

Precision metal stamping can make thousands to millions of parts in a single run. This is more productive than other metalworking processes such as CNC machining, fabrication or welding.

This process is ideal for high volume manufacturing, where hardware parts are manufactured in large volumes.

2. Uniformity

Precision metal stamping is versatile, the same tooling can be used to produce a variety of components, and requires little additional setup or adjustment between production runs.

Therefore, precision metal stamping has higher uniformity compared to other industrial processes. Since all products are stamped from sheet, they have the same wall thickness and nearly the same surface finish, making post-production assembly and quality control inspections easier.

Precision metal stamping also supports mass customization of final products through automated variable design to quickly meet unique customer requirements.

3. Quality

Precision metal stamping is a versatile process capable of producing a range of parts with varying surface finishes and tolerances.

It also produces parts with thin walls, deep draws and undercuts that would otherwise be challenging to produce using other processes such as CNC machining or fabrication.

This makes precision metal stamping an excellent choice for aerospace, medical implants, automotive, lighting and consumer electronics product development where precise shapes and thin walls are required.

Precision metal stamping is one of the few technologies capable of producing the specific thin-wall geometries required for demanding electronic packaging applications due to its ability to create deep-drawn features.

4. Ease of use

Engineers and designers find precision metal stamping easy to use because it can replace complex shapes with minimal tooling.

This capability provides customers with greater design flexibility and opens the door to conceptual exploration early in product development.

It also helps them reduce costs by minimizing material waste, as fewer mold changes are required with each new part design iteration.

Using precision metal stamping makes it easier to manufacture precisely designed parts because they require less machining time for secondary operations throughout the production process. This results in a more efficient workflow, especially at high volumes.

5. Minimize material waste

Precision metal stamping is an economical manufacturing process because it uses the minimum amount of material needed to make the part.

This feature allows manufacturers to manufacture thin-walled products without the need for complex secondary operations, such as CNC machining, which can be time-consuming and expensive.

6. Cost-effectiveness

Compared to large die casting machines for mass production, precision metal stamping has lower start-up costs. Therefore, it is beneficial when the production demand is not large but the volume is still high.

It also provides a high degree of flexibility, with design options available to manufacturers for custom-made items that cannot be produced any other way. This means they can earn higher profits without much initial investment.

7. Least secondary operations

For precision metal stamping, secondary operations, such as cutting threads after production, are usually not required. The process simultaneously creates accurately shaped features without any errors, such as pre-drilling, countersinking, or cutting threads. Secondary machining often adds cost and time-to-market, but hand-finishing is minimal after stamping, again saving money and time.

3. Precautions when using precision metal stamping technology

1. Surface quality

The surface quality of a stamped part depends on the metal used, its hardness, thickness and whether it is heat treated after stamping. Softer materials are more prone to scratching during the stamping process, while thicker metals are less prone because they are more resistant to pressure from the tool. Heat treatment helps improve the grain structure of the metal, making it harder and more resistant to wear without compromising the strength of the material.

2. Undercut

Undercuts can cause difficulties during stamping because they make it difficult for the tool to fully penetrate the sheet metal.

One way to get around this is to use a progressive die instead of one big die to cut out the shape of all the parts at once. Multiple dies perform small cuts until all part features are achieved. Progressive punching also reduces the force required to release the undercut, but it also limits production speed and can lead to irregular shapes that require secondary operations to clean up.

3. Tolerance and Accuracy

Tolerance refers to the amount of variation allowed in dimensions in the part design, while accuracy refers to how close the final measurement is to the expected dimensions.

Precision metal stamping can achieve precise dimensions and tight tolerances because, unlike other manufacturing processes, it uses controlled forces to produce parts.

Parts produced using this process are closer to specification than parts made using alternative methods such as CNC machining or welding.

4. Material strength and tool wear

To keep costs low, manufacturers often use softer, cheaper metals to make tools. However, using less robust tooling results in a compromise in material strength that can adversely affect design and quality, especially when the product requires thin-walled geometries. Such tools can place excessive compressive stress on components.

Stress from the tool is a major cause of material deformation, so this trade-off must be considered when designing metal stampings.

5. Product complexity and cost

The complexity of a part’s design determines how many tools are required to manufacture all its features. However, manufacturers may address this cost by performing secondary operations on specific components in the same production run, rather than making unique tooling for complex shapes or geometries such as undercuts.

This allows manufacturers to produce multi-component products in multiple materials at once without increasing costs.

4. Summary

Precision metal stamping is used in a variety of industries to produce metal parts with complex geometries and other features that are too costly or impossible to manufacture with alternative manufacturing methods such as die casting and machining.

While manufacturers need to consider budget, machine capacity, tool quality, and other factors when choosing the right process for their business, precision metal stamping is known for its accuracy.

How to choose raw materials for automobile stamping parts?

A large number of cold stamping processes are used in the processing and production of automobile stamping parts, which meets the requirements of the automobile stamping parts processing industry for various varieties and production. Medium-heavy vehicles, large-sized surface cage parts, such as body outer panels, and some load-bearing and support parts, such as frame, carriage and other auto parts, are processed by automotive stamping parts. The cold stamping parts are made of steel plates and steel belt fasteners, accounting for 72.6% of the total installed steel volume. The relationship between cold stamping die materials and automotive stamping parts processing and production is very close. The quality of the product not only determines the performance of the product, but also directly affects the process planning of the automotive stamping parts processing process, and affects the quality, aging, service life and production structure of the product. Therefore, the selection of suitable raw materials is one of the important factors, and it is also a very difficult and complicated task.

Generally, the car stamping parts we use are all directed to beautiful, applicable and economical. However, when weighing the quality of stamping parts, we should pay more attention to the number of processes of stamping parts. In addition, reducing the number of processes and simplifying the operation process in the stamping process is also a difficult problem. Then, when commenting on the quality problems of car parts, it can also be identified by the layout of stamping parts.

Of course, a small number of car stamping parts use a little standard when judging the quality. In the process of application, it is not easy to describe with pen and ink, but there is a little standard or existence for judging the quality.

Common defects in car stamping materials include burrs, wood surface warpage, and dimensional deviations.

Automobile connecting rod stamping parts are generally difficult to avoid poor burrs, but if the processability of the formed products is improved and the stamping conditions are improved, the burrs can be reduced.

This is a glitch, a little more important:

1.1 Clearance

The gap of the stamping parts is too large, too small or uneven, which will cause burrs. The main reasons for gaps that are too large, too small, or uneven are as follows:

– Mould manufacturing error – The processing of mould parts does not conform to the drawings, the parallelism of the bottom plate is poor, etc.

Assembly error – large guide rail clearance, poor concave-convex assembly, etc.

Poor pressure accuracy – For example, the clearance of the press guide rail is too large, the parallelism between the bottom of the rocker plate of the slider and the surface of the table is poor, probably because the sliding distance of the slider and the verticality of the table of the press are poor, and the rigidity of the table is poor.

d Installation error – For example, the upper and lower bottom surfaces of the mold are not wiped clean during installation, the fastening technique of the upper mold of the large mold is wrong, or the center of the upper and lower molds (especially the non-guided mold) may be installed, and the movement is unilaterally skewed.

The layout of the e-die is divided into the lack of rigidity of the die head and one-sided, and the unbalanced force of automobile stamping parts.

The curvature of the steel hoist is large – the steel plate is not satisfied.

1.2 The knife edge is slow.

Slow sharpening or biting can cause burrs. The influencing factors of edge passivation are:

Die convex, concave and convex materials and their surface treatment conditions are not good, poor wear resistance.

Poor typography, poor rigidity, and crunch.

It cannot be lubricated in time during operation and wears quickly.

d The geodetic front cannot be ground immediately.

The above is related to the processing of automobile stamping parts. There are many kinds of automobile stamping parts, so the selection of stamping parts also has strange specifications. And there must be a good treatment method for the common defects in the processing of automobile stamping parts. I hope the above can be helpful to readers.

Metal stamping parts processing, stamping parts stretch forming method

Products are drawn using stamping equipment including:

1. Tension treatment:

The plate pressing device uses the punch of the punch to pull part or all of the plate into the die to make it a bottomed container. For the drawing process of a conical (or pyramidal) container, a hemispherical container, a parabolic container, etc., the side walls thereof are parallel to the drawing direction, and the expansion process is also included.

2. Pull back processing:

That is to say, for a deep-drawn product that cannot be completed by one-time drawing, after the drawing process, the formed product needs to be drawn again to increase the depth of the formed container.

3. Reverse drawing processing:

Use the tension punch in the previous process to pull back, so that the inner wall of the workpiece becomes the outer side and the outer diameter is reduced.

4. Thin stretch processing:

The shaped container is extruded through a punch into a female cavity that is slightly smaller than the outer diameter of the container, thereby reducing the outer diameter of the container with the bottom, reducing the wall thickness, eliminating offset, and allowing the surface of the container to smooth.

Precautions for processing of pressed and drawn parts

1. The shape of the metal stamping and drawing die should be as simple and symmetrical as possible, and it should be stretched at one time.

2. For parts that need to be stretched many times, under the premise of ensuring the necessary appearance quality, there should be possible stretch marks on the appearance.

3. In order to ensure the installation requirements, the side wall of the extension piece should have a certain inclination angle.

4. The distance between the bottom surface of the telescopic piece or the hole edge of the flange and the side wall should be appropriate.

5. The bottom-wall surface, flange and wall surface of the drawing piece, and the radius of the four corners of the rectangular part should be appropriate;

6. The ruler, inner and outer shape of metal punching and drawing parts cannot be uniformly marked.

The above content is related to the processing of metal stamping parts. In fact, in the final analysis, the quality and performance of the stretched parts are the key, and the later use is also a basic principle. Of course, in the process of processing and production, the product will not have any defects, what we have to do is to reduce these failure rates to a very small amount. Thereby, the production efficiency of the stretched parts is improved. Hope the above content is helpful to readers.

What are the points of attention for the design of precision drawing molds during the processing and production of drawing parts?

First, the shortcomings of the current upward continuous stretching die.

1. The thickness of the template is not uniform. The key to the stretching die is the stripping plate, which should be thickened and the splint should be appropriately thinned.

2. The guide gap of the drawing die is large, the die and the guide post, especially the stripper plate and the guide post, the gap between the punch and the guide post is large, and the precision of the guide post is poor.

3. The choice of the spring is not very reasonable. The key to the stretching die is the blank holder, and it is necessary to ensure that the stretching cannot be wrinkled.

2. What should be paid attention to when the continuous stretching die is stretched upward?

1. Thickness of the template: Because the upper mold needs to be equipped with a spring or a nitrogen gas spring, the upper cover plate is 25mm thick as far as possible, and the upper foot is determined according to the height of the stretched product and the cover degree of the spring required.

2. Upward stretching is actually a very critical point. It is a product orientation problem, especially for products with high stretching. It is easy to deform during the stretching process. If the product is crooked, it is difficult to guide. Then every step of stretching The question of orientation is the key.

3. Clearance: stretch upward, the inner guide should be neutral as far as possible, fixed on the stripper plate, which is conducive to disassembly. Colleagues use ball guide posts, which rely on the rotation of the ball to slide, so that the guiding accuracy can be guaranteed.

4. Selection of springs: D. A group of trimming generally chooses springs that can be stripped. At the beginning, the upper springs need to bear the stretching effect, so nitrogen gas springs are required. According to the product material and the size of the material, the thickness of the material must be Choose different tonnages, try not to choose large ones, because the blanking plate needs to arrange at least 4 springs. Not only that, but also different colors of springs need to be selected according to the thickness of the material and the diameter of the material. The subsequent stretching is based on a principle that the lower spring is smaller than the upper spring, and the lower spring can be stripped.

The continuous mold production process adopted by Baifudu Electromechanical Stamping, multiple processes are completed in the same mold, and the one-time molding of the product is realized. The precision of the finished product is higher and the quality is more stable. It can produce various stainless steel tensile parts, Drawing shells, stamping deep drawing parts, metal deep drawing parts, shell drawing parts, etc., what are the points to pay attention to in the design of precision drawing molds during the processing and production of drawing parts. The relevant content is as above, I hope it can help you.

Stamping die design method and operation steps are introduced in detail

1. Analysis of stamping process of stamping parts

Stamping parts must have excellent stamping process, so that qualified stamping parts can be produced in the simplest and most economical way, and the process analysis of stamping can be completed according to the following methods:

1. Be able to read the part drawing: In addition to the shape and size of the part, the key points are to understand the requirements of the part accuracy and surface roughness.

2. Analyze whether the structure and shape of the parts are suitable for stamping processing.

3. Analyze whether the benchmark selection and size marking of parts are reasonable, and whether the accuracy of size, orientation and shape is suitable for stamping processing.

4. Whether the rough surface requirements of the blanking section are too high.

5. Whether there is a strong enough production batch.

If the craftsmanship of the part is too poor, the planner should be communicated and a plan to revise the plan should be proposed. Assuming the production batch size, other production methods should be considered for processing.

2. Stamping process planning and best process design.

1. According to the shape and size of the stamping parts, start to judge the nature of the stamping process, such as punching, bending, deep drawing, bulging, reaming and other stamping die planning methods and processes.

2. Calculate the degree of deformation of each stamping method. If the degree of deformation exceeds the limit deformation degree, the number of punches for the process should be calculated.

3. According to the deformation characteristics and quality requirements of each process, organize a reasonable stamping sequence. Care should be taken to ensure that the deformation area of ​​each process is a weak area, and the formed parts (including punched holes or shapes) must not participate in deformation in subsequent processes. Polygonal zigzag parts should be bent first and then bent inward, and necessary auxiliary processes and processes such as shaping, leveling, and heat treatment should be organized.

4. On the premise of ensuring the accuracy of the parts, according to the production batch and the blank positioning and unloading requirements, determine a reasonable process combination method.

5. More than two process plans should be planned, and the best process plan should be selected from the aspects of quality, cost, productivity, mold sharpening and repair, mold life, operation safety, etc.

6. Start to judge the stamping equipment of each process.

3. Blank planning and layout drawing design of stamping parts

1. According to the performance scale of stamping parts, calculate the blank size and make a blank drawing

2. According to the roughness scale, plan the layout drawing and calculate the data utilization rate. To plan a variety of nesting plans, choose the best plan by comparison.

Fourth, die design

1. Determine the die structure method of each process of stamping processing, and make a schematic diagram of the die.

2. Carry out specific structural planning for the 1-2 processes specified by the mold, and make the mold operation diagram. The planning method is as follows:

(1) Determine the type of mold: whether it is a simple mold, a continuous mold or a composite mold.

(2) Design of mold working parts: Calculate the size of the edge of the convex and concave molds and the length of the convex and concave molds, and determine the structure and connection and fixing methods of the convex and concave molds.

(3) Determine the positioning and spacing method of the blank, and plan the corresponding positioning and spacing parts.

(4) Determine the pressing, unloading, ejecting and pushing methods, and plan the corresponding pressing plates, unloading plates, and pushing blocks.

(5) Formwork design: It includes the design of upper and lower die bases and guiding methods, and standard formwork can also be selected.

(6) On the basis of completing the above operations, make a mold operation diagram according to the scale. First make blanks with double-dot-dash lines, then make parts, then make positioning and spaced parts, connect the above parts with connecting parts, and finally make pressing and unloading parts in the proper position. According to the specific conditions of the mold, the above order can also be adjusted appropriately.

(7) The outer contour size of the mold, the closed height of the mold, the cooperation size, and the design method and process mold design of the cooperation type stamping die should be marked on the work map. The job drawing should indicate the requirements of the production accuracy and skill conditions of the mold. The job drawing should be made according to the national drawing standards, with a standardized title bar and detailed table. If it is a blanking die, make a layout drawing on the upper left corner of the work drawing.

(8) Calculate the pressure center of the mold and check whether the pressure center coincides with the center line of the mold handle. If they do not coincide, make corresponding corrections to the mold results.

(9) Calculate the punching force, finally select the punching equipment, and check the relevant dimensions of the die and the punching equipment (closed height, work surface, die handle device dimensions, etc.).

What are the common problems in the production of stamping and drawing parts?

1. The reason for the instability and wrinkling of the flange of the stretched part: the blank holder force is too small, or the relative thickness of the blank is small, or the tensile coefficient is too small.

Solution: Increase the blank holder force or increase the number of stretches.

2. Reasons for surface strain of stamping and drawing parts: low heat treatment hardness, poor finish, improper material selection, excessive material thickness, wear of concave die fillet, poor surface quality of bending blank, unreasonable selection of process plan, insufficient lubrication, etc.

Solution: For stamping parts that need to be stretched many times, under the premise of ensuring the necessary appearance quality, there are traces that can occur during the stretching process. Choose suitable materials and process solutions, lubricate and reduce friction.

3. Reasons for the inconsistent shape and size of stamping and drawing parts: due to inaccurate positioning, in addition to taking measures to reduce springback, the reliability of blank positioning should also be improved.

Solution: The shape of stamping and drawing should be as simple and symmetrical as possible, and one-time stretching should be done as much as possible.

4. The reason for the cracking of the hole after the stretching of the tensile member with the hole: the hole diameter is too large, so that the material around the hole is subjected to a large tensile stress, which leads to fracture.

Solution: Change the sequence of forming process, stretch and form first, and then punch holes at the bottom.

5. The reason for the instability and wrinkling of the upper edge of the cylindrical drawing part: the radius of the concave die fillet is too large, which causes the gap between the concave die and the punch die to be too large, or the blank holder force is too small.

Solution: increase the blank holder force and reduce the radius of the die fillet.

In the drawing process, the cylindrical drawing part is a common metal drawing part, which is widely used. Some customers have special requirements for stretched parts, such as flanging, etc., which can meet the special requirements of the product. Drawing parts processing plants need to fully understand the knowledge of drawing parts flanging processing.

Cylindrical stretching parts with flanging include narrow flanging, cylindrical stretching parts and wide flanging cylindrical stretching parts; narrow flanging cylindrical punching and stretching parts are stretching parts with a small total flange width . When this type of parts is stretched many times, due to the narrow flanging, it can be stretched by punching the flanging cylinder first, and then the flanging process is performed to form the specified narrow flanging shape.

In order to make the flanging better, the conical concave die and the conical pressing ring can be selected for stretching in the last two processes of drawing, and the conical flanging can be vacated, so that the flanging area can be reduced when the part is formed. Radial tensile deformation is beneficial to avoid edge cracking.

When the wide-flanged cylindrical stretched piece needs to be stretched multiple times, for the first stretch, make sure that the flanging specification is equivalent to the flanging specification of the stretched piece. In the next stretching, the flanging specification No change, only the raw material in a certain part of the cylinder migrates to the stretch specification. Because in the subsequent stretching process, even a small deformation caused by a part of the flanging will cause a very large tensile stress in the force transmission area of ​​the cylinder wall, thereby causing the bottom section to crack.

What are the common materials in the production of stamping and drawing parts?

1. Stainless steel stamping and drawing parts

Stainless steel tensile parts have the characteristics of high strength, light weight, good wear resistance, and high corrosion resistance. The tensile parts of this material do not require electroplating protection. It is suitable for heat treatment and is often used in fuel systems, braking systems, exhaust systems, oxidation sensors and decorative parts in automobile manufacturing.

2. Low carbon steel stamping and drawing parts

Low carbon steel has the characteristics of excellent formability, stable forming dimensions, high strength, and light weight (see material grade for details). It is often used in various parts in automobile manufacturing, especially high-strength mechanism parts.

3. Aluminum alloy stamping and drawing parts

The characteristics of aluminum alloy tensile parts are: light weight (almost 1/3 of low carbon steel), high strength, non-magnetic, stainless rust, anodized anti-corrosion, suitable for heat treatment, etc., and are often used in bulk in automobile manufacturing and other industries. devices, energy storage devices, beverage containers and the pharmaceutical industry.

4. Copper alloy tensile parts

Copper alloy drawing parts have the characteristics of stable forming dimensions, corrosion resistance, good ductility, and easy welding. The disadvantage is that they are easy to oxidize. Due to the high price of copper alloy materials, waste needs to be reduced and recycled if necessary.

The above is related to the processing materials of stamping and drawing parts. In general, the machining methods for machining parts from different materials will vary. Material properties and processing characteristics should be considered to avoid losses. Hope the above content is helpful to readers.

What are the types of metal stamping and drawing parts?

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Stamping equipment is used for drawing and forming of products, including drawing, redrawing, reverse drawing and thinning.

Drawing processing: Using the platen device and the punching force of the punch, part or all of the flat plate is pulled into the cavity of the female die to form a bottomed container. The sidewall of the container is processed parallel to the drawing direction, and the deep drawing processing of conical (or pyramidal) containers, hemispherical containers, and parabolic containers also includes expansion processing.

Re-drawing: For deep-drawn products that cannot be completed by one-time drawing, the formed product needs to be re-drawn to increase the depth of the formed container.

Reverse drawing processing: The drawing workpiece of the previous process is reversely drawn, and the inner side of the workpiece becomes the outer side, making its outer diameter smaller.

Thinning and drawing processing: The forming container is squeezed into the concave mold cavity slightly smaller than the outer diameter of the container through the punching machine, so that the outer diameter of the bottomed container is smaller and the wall thickness is thinner, which not only eliminates the wall thickness deviation, but also makes the container surface smooth. .

When using stamping equipment for metal stamping and drawing, the following 16 types are included:

1. Cylinder drawing

Drawing of cylindrical products with flanges (flanges). The flange and the bottom are both plane shapes, the side wall of the cylinder is axisymmetric, the deformation is evenly distributed on the same circumference, and the blank on the flange is deep-drawing deformation.

2. Elliptical drawing process

The deformation of the blank on the flange is tensile deformation, but the deformation amount and deformation ratio change correspondingly along the contour shape. The greater the curvature, the greater the plastic deformation of the blank; conversely, the smaller the curvature, the smaller the plastic deformation of the blank.

3. Rectangular drawing process

A low rectangular piece formed by one stretch. During stretching, the tensile resistance at the rounded corners of the flange deformation zone is greater than that at the straight edge, and the degree of deformation at the rounded corner is greater than that at the straight edge.

4. Yamagata drawing process

When the side wall of the stamping part is inclined, the side wall is suspended during the stamping process, and the mold is not attached until the end of forming. The deformation characteristics of different parts of the sidewall during the forming process are not exactly the same.

What is the cause of delayed cracking in the processing of stainless steel drawing parts?

1. Delayed cracking of austenitic stainless steel. (such as 200 series, represented by 304, 300 series, etc.)

The delayed cracking of austenitic stainless steel is mainly determined by its own structure, and the degree of work hardening of austenitic stainless steel is relatively large. After stretching, in addition to the residual internal stress generated by cold working, the austenite structure also undergoes martensitic transformation at the mouth. To prevent cracking of the mouth, it is necessary to eliminate residual stress and martensitic structure, so that it can undergo phase transformation at high temperature. Austenitic stainless steel takes 304 as an example, and the annealing temperature is 1010-1050 degrees Celsius. Generally, in order to avoid the overall annealing deformation of the stretched part, only the mouth of the stretched part is annealed, and the relatively fast one is high-frequency annealing.

2. Delayed cracking of ferritic stainless steel. (For example, 400 series stainless steel represented by 430, commonly known as stainless steel)

Ferritic stainless steel does not change after stretching, and product cracking is mainly caused by residual stress. In order to ensure safety, from experience, for cylindrical deep-drawn parts, when the aspect ratio is greater than or equal to 0.8 and the diameter is greater than or equal to 300, annealing treatment is required. Of course, if cracking occurs when the aspect ratio is less than 0.8, annealing should be arranged immediately.

When using stainless steel or ferritic stainless steel materials, the use of stamping and drawing oil can reduce the breakage rate of the product and reduce the cost. The lubrication state of stamping is a mixed state of fluid lubrication and boundary lubrication. If only mineral oil is used, the strength of the oil film will not meet the requirements, and the oil film will be easily broken, which will cause metal-to-metal contact to produce sintering. The use of oily agents can make up for this deficiency. One end of the oily agent molecule contains polar groups such as carboxyl group, hydroxyl group and ester group. These polar groups can chemically or physically adsorb oily agents and form a solid lubricating film on the metal surface, thereby improving lubricating performance.

However, when the friction surface temperature rises to a certain temperature, the molecular arrangement of the oily agent adsorption film will be destroyed and the lubricating effect will be lost. At this time, the boundary lubricating film covering the surfaces of the two metals disappears, resulting in direct contact between the metals. As the direct contact area increases, the frictional energy also increases, resulting in an increase in temperature and a tendency to occur so-called sintering. In this case, the additive used to prevent direct contact between the two metal surfaces is an extreme pressure agent, even at elevated temperatures. Extreme pressure agent (EP) is a kind of boundary lubricating film that uses the high temperature generated on the friction surface to chemically change itself, generate shear force on the friction metal surface, and play an effective protective role.

Stretching of stainless steel hardware, equipment, molds and stretching oil are key factors. Otherwise, no matter how good the personnel and technology are, it is difficult for a clever woman to cook without rice, and cannot make high-quality products.

Metalworking Manufacturing Statistics: The design life of drawing equipment is about 10 years, which is caused by factors such as the equipment itself, overuse and improper maintenance. In the process of metal drawing, improper selection of drawing oil will lead to accelerated wear and tear of many equipment, and some will be paralyzed in a few years, which directly affects the operation of the whole plant and cannot maximize benefits.

How to calculate the mold processing of metal drawing parts?

First, learn to stretch the expansion

The expansion of the stretched parts can be divided into two types: software expansion and manual expansion. For the expansion of general cylindrical parts, it is generally feasible to use software and manual expansion. For complex curved parts, irregular products, Then we can use software to expand, for example: one-step expansion of UG software, or expansion with AUTOFORM software is possible. Its principle is to assume that the material does not change in volume without thinning. principle.

Then the computer expansion is based on the finite element analysis and calculation to obtain an expansion result, which is usually the result under ideal conditions and has a great reference value. Manual expansion is the radius of expansion obtained by mathematical calculation, so manual expansion can only be a conventional method of mathematical calculation.

2. Learn to calculate the stretching parameters

The biggest problem that troubles us in the stretching calculation is how many times a piece can be pulled out, and how to determine the size of each time? Masters who have done stretching molds are generally confused about this piece. If you can calculate, it will be like clearing the clouds and seeing the sun. A very important parameter in the stretching parameters is the stretching coefficient M, which is a ratio to put it bluntly, and is an empirical parameter summed up by predecessors in long-term practice. Tensile coefficient M = finished product size d / blank size D, when this coefficient is less than the ultimate tensile coefficient of a certain material, then we assess that the product cannot be pulled out at one time, that is, there is a risk of rupture. Of course, the stretched parts are also closely related to the forming R of the product and the size of the blank holder. There are many parameters involved. For details, you can consult the relevant stretching data for details.

3. Process layout

The process design is to calculate the stretched size according to the result of the stretching calculation, but the calculation is quite complicated each time the height is stretched. In order to obtain the stretched height more intuitively and easily, the CAD software can be used for simulation calculation. Adjust the height value of the stretch a few times to determine the correct height value for each stretch, still following the principle of constant volume. Of course, expressing computation in words is a difficult process. It takes practice to really master it.

The last thing I want to tell you is that stretching is not as difficult as you think. Find experienced people to learn the method, then many problems will be solved easily.

The above is the relevant content about the calculation of mold processing for metal drawing parts. For those who are not familiar with the field, mold processing is more complicated, and the failure rate is high. People in the industry can be said to be at their fingertips. Hope the above content is helpful to readers