What are the common faults of metal stamping parts?

According to the practical experience of quality management in our company’s stamping plant, the reasons and countermeasures for common problems in the production process of metal stamping parts are summarized, hoping to provide a useful reference for improving the quality of parts in the stamping plant.

1. Why do metal stamping parts appear twisted?

The stamping part is formed by punching the remaining material around the stamping part in the progressive die to form the shape of the stamping part. The main reason for flanging and twisting of stamping parts is the influence of blanking force. During punching, due to the existence of the punching gap, the material is stretched on the die side (the material is warped upward) and compressed on the die side. When using a stripper, press the material with the stripper to prevent the material on the die side from warping upwards. At this time, the stress state of the material also changes accordingly. As the stripper pressure increases, the material on the punch side is stretched (the pressure tends to decrease), while the material on the die surface is compressed (the tension tends to decrease). The reversal of the stamping is caused by the stretching of the material on the die surface. Therefore, when punching, pressing the material is the key to preventing the punch from flipping and twisting. Causes and countermeasures of flanging and twisting when stamping parts are bent.

It is caused by the burrs of the blanking parts during blanking. It is necessary to study the punching edge, and pay attention to check whether the punching gap is reasonable.

During the blanking process, flanging and deformation of the blanking parts occur, resulting in poor forming after bending, which needs to be solved from the blanking and blanking station.

Stamping parts are unstable during bending and are mainly used for U-shaped and V-shaped bending. In response to this problem, the key to solving the problem is to guide the position before bending, guide during the bending process, and press the material during the bending process to prevent the stamping parts from slipping during the bending process.

How to reduce the concave and convex problem of metal stamping parts?

1. Five methods to reduce the concave and convex of stamping parts

1. Inspection and correction of drawing dies: Everyone should know that drawing dies need to be inspected and maintained regularly to avoid reducing the production of convex and concave and maintain a stable state. The usual practice is to use samples to check the bonding scratches of the blank holder and the condition of the machined surface (concave die fillet, punch die fillet).

2. Inspection and correction of the shearing die: The reason for the concave and convex after the shearing process is that iron powder is generated during the shearing process. The iron powder must be observed before stamping to avoid the occurrence of convex and concave.

3. Appropriate manipulator speed: For the production of semi-automatic drawing molds, when the drawing mold is in the lower mold position and the manipulator speed is fast, the burr will fall on the upper part of the punch, resulting in unevenness. In order to avoid this problem, we can carry out the part discharge test before production, and set the speed and discharge angle of the manipulator reasonably to avoid contact with the parts and the die.

4. Check the cut surface: When cutting the material, the wear and damage of the cut die will produce a large amount of small iron powder attached to the cutting edge. Therefore, before stamping production, it is necessary to check the secondary cut surface in the material area or stamping line, and clean the plate in time to remove burrs.

5. Inspection of the plate cleaning device: Before stamping production, it must be inspected and repaired at the same time to clean the plate more effectively. It is also necessary to pay attention to the quality of the roller gap and cleaning oil. The specific method is to apply red paint on the steel plate to make it cleaned and installed. At present, the cause of the removal of the red paint is checked. If the removal rate is not up to standard, it is necessary to check and repair the cleaning and installation. When the cleaning oil is lacking, it must be reduced in time.

What are the common materials for precision metal stamping dies?

In the industry, hardware is generally divided into large and small hardware. Big hardware refers to steel plate, steel bar, flat iron, universal angle steel, channel iron, I-beam and various types of steel materials, while small hardware mainly refers to construction hardware, white iron sheet, lock nails, iron wire, steel wire mesh, wire scissors , household hardware, various tools, etc. As far as the nature and use of hardware are concerned, it should be divided into eight categories: steel materials, non-ferrous metal materials, mechanical parts, transmission equipment, auxiliary tools, work tools, construction hardware, and home hardware. There are also many varieties of hardware products. Relatively speaking, the difference in specifications is relatively large. It plays an irreplaceable role in home decoration. Choosing a good hardware mold processing factory can increase the processing accuracy and improve the use process. safety, while also increasing the service life.

The stamping materials often used in precision metal stamping processing include beryllium copper BECU, steel plate SK, phosphor bronze PB, tinplate SPTE, aluminum AL, stainless steel plate SUS, white copper NS, hot-rolled steel plate SECC, cold-rolled steel plate SPCC, etc. Moreover, the material of stamping metal stamping has good plasticity, and the bright band of our stamping products will be larger and the fracture band will be smaller.

Precision metal stamping parts can also be divided into various types according to industry, use and process characteristics. Next, the types of precision metal stamping parts are introduced as follows:

1. Auto parts: mainly include automotive structural parts, automotive functional parts, automotive lathe parts, automotive relays, etc.

2. Electronic parts: mainly include connecting devices, connectors, brush parts, electrical terminals, elastic parts, etc.

3. Appliance parts: It mainly includes major appliance parts, such as color tube electron gun parts, as well as small appliance parts, various structural parts and functional parts.

4. IC integrated circuit lead frame: mainly includes discrete device lead frame and integrated circuit lead frame.

5. Motor core: mainly includes single-phase series motor core, single-phase household motor core, single-phase shaded-pole motor core, permanent magnet DC motor core, industrial motor core, plastic-encapsulated stator core, etc.

6. Electrical iron core: It mainly includes E-shaped transformer core, EI-shaped transformer core, I-shaped transformer core, and other transformer cores.

7. Heat exchanger fins: mainly include industrial heat exchanger fins, household heat exchanger fins, automotive heat exchanger fins, etc.

8. Other parts: mainly include instrumentation parts, IT parts, acoustic and camera parts, modern office parts, and daily hardware.

What are the methods of hardness testing of metal stamping parts?

First, the method of hardness testing of metal stamping parts

The hardness test of metal metal stamping parts adopts Rockwell hardness tester. Small stampings with complex shapes can be used for small test surfaces, which cannot be tested on ordinary benchtop Rockwell hardness testers.

The processing of metal stamping parts includes blanking, bending, deep drawing, forming, finishing and other processes. The processing materials of metal stamping parts are mainly hot-rolled or cold-rolled (mainly cold-rolled) metal sheets and strips, such as carbon steel sheets, alloy steel sheets, spring steel sheets, galvanized sheets, tin-plated sheets, stainless steel sheets, copper and copper. Alloy plate, aluminum and aluminum alloy plate, etc.

The PHP Series Portable Surface Rockwell Hardness Testers are ideal for testing the hardness of these stampings. Alloy stampings are the most commonly used parts in the fields of metal processing and machine manufacturing. Stamping is a processing method that uses a die to separate or form a sheet metal strip. Its application range is very wide.

The main purpose of the stamping material hardness test is to determine whether the annealing degree of the purchased metal sheet is suitable for the subsequent stamping processing. The same type of stamping process requires sheets of different hardness levels. Aluminum alloy plates used for stamping parts can be tested with Webster hardness tester. When the thickness of the material is greater than 13mm, it can be replaced by a barcol hardness tester, and a barcol hardness tester should be used for pure aluminum plates or low-hardness aluminum alloy plates.

In the stamping industry, stamping is sometimes also called sheet forming, but it is slightly different. The so-called plate forming refers to a forming method in which a plate, a thin-walled tube, a thin profile, etc. are used as raw materials for plastic processing. At this time, the preparation of the thick plate direction is generally not considered.

Well, the above is the relevant content about the hardness testing method of metal stamping parts, I hope the above content can help readers.

What are the precautions for metal stamping?

1. What are the preventive measures that should be taken during metal stamping processing?

1. We should regularly check the punch turntable and the die mounting seat of the stamping part to better ensure the coaxial accuracy of the upper and lower turntables.

2. Metal stamping parts need to be strictly inspected before installation and use, and the dirt should be removed. The guide bushes of stamping parts and die casting dies should be carefully checked for good lubrication.

3. In order to ensure the service life of the stretched and compressed parts, the spring of the die should also be replaced regularly to prevent the fatigue damage of the spring from affecting the use of the stretched stamping parts.

4. When installing the mold, the stamping personnel should use soft metal manufacturing tools to prevent the stamping parts from being damaged by impact and extrusion during the installation process.

5. The wear of the convex and concave die edges of the stamping parts should be stopped and polished in time, otherwise the wear degree of the die edge will expand rapidly, the die edge wear will be accelerated, and the stamping quality and die life will be reduced

What are the preventive measures for metal stamping processing above? I hope the above content can help readers!

What are the common problems in mold design and processing?

1. Why does the mold turn over less frequently?

In the process of making the mold, too much silicone oil is added, and the silicone oil destroys the molecular weight of the silicone, so the number of times the mold is turned over is small and not durable. If it is said that small products with complex patterns are used to open the mold with silicone with high hardness, there will be a phenomenon that the number of mold turning is less, because the time when the silicone is too hard will be very brittle and easy to break. On the contrary, if the mold is made of silicone with less hardness, the result is not satisfactory. Since the silicone is too soft, its tension and tear strength will decrease, and the mold will deform, so the number of flips will decrease. The quality of the mold glue itself is very good, and the silicone is not good or bad, only suitable or not. This does not happen when we make molds with silicone that is suitable for the hardness of the product.

2. Why does the mold burn out?

Since the unsaturated resin and resin products are added with peroxide curing agent, the resin reaction will generate a lot of heat. The resin curing time is generally 3 minutes, and the mold is released as soon as possible after 3 minutes to prevent the phenomenon of silicone mold burning.

3. The method of filling the mold and the production method of the slicing mold

The operation method of the slicing mold or the slicing mold: brush or pour the vacuum silica gel for construction. If you are making a sheet mold or a split mold and using the brushing method, apply a layer of release agent or release agent to the product or model to be replicated before painting, then apply silicone to the product and wait 30 minutes. Apply a layer of gauze or fiberglass cloth to the surface for strength, then apply a second layer of silicone. After the silica gel is dried, the outer mold is made. The outer mold can be made of materials such as plaster or resin.

The operation method of the pouring or pouring mold: the pouring or pouring mold is used for smooth or simple products, that is, the product or model to be copied is surrounded by a plastic or glass plate, and the vacuum silicone is directly poured into the product. After the silica gel is dried and formed, the product is taken out and the mold is formed. The above is the whole process of mold use and operation.

4. Why does the mold appear dry on the outside and not dry on the inside?

The mold is a condensed silicone that cures by absorbing moisture from the air. Silica gel evaporates water during the production process, and this happens without adding an appropriate amount of water.

5. Why does the mold have poor tensile force?

Because in the process of making the mold, in order to reduce the viscosity of the silica gel and make the silica gel easy to handle, a large amount of silicone oil is added to the silica gel to make the silica gel very soft, resulting in the phenomenon of intolerance, reduced tear strength, and poor tensile force. , resulting in the phenomenon that the mold is not durable, the service life is short, and the number of mold turnovers is small.

6. Why does the mold appear oily?

The mold itself will not emit oil, because the complex silicone oil (silicone oil and white mineral oil complex) is added during the operation, because the white mineral oil is a petrochemical product, not a silicone oil.

7. Why does the mold made by the mold have traces, streaks, and unevenness on the surface?

This phenomenon occurs why the product or model to be reproduced is not ground or polished. Because in fact, the model or product itself is not smooth or perfect, if the product or model to be reproduced is not sanded or polished, no matter how good the mold made of silicone, it will not be beautiful and smooth. Another situation is that when removing the mold, uneven brushing can also cause the mold to be uneven.  

What is the reason for the failure of stamping and drawing dies in processing and casting?

1. The process of stamping and drawing die

Punching die is a method of casting liquid die forging, a process completed on a special die-casting die forging machine. The basic process is: the molten metal is first cast into the mold cavity at a low speed or high speed, and the mold has a movable cavity surface. With the cooling process of the metal liquid, pressure forging not only eliminates the shrinkage defect of the blank, but also makes the internal structure of the blank reach forging. Broken grains.

2. The main reasons for the failure of stamping and drawing dies are as follows:

1. Thermal fatigue crack damage failure

During die-casting production, the mold is repeatedly subjected to the action of cold and heat, the forming surface and its interior will be deformed, and they will be pulled together to generate repeated thermal stress, which will cause damage to the structure and loss of toughness, which will lead to the occurrence of micro-cracks and continue to expand. , once the crack expands, the molten metal is continuously squeezed in, coupled with repeated mechanical stress, the crack accelerates the expansion rate. Therefore, the mold must be fully preheated at the beginning of die casting. In addition, during the production process of die casting, the mold must be kept in a moderate working temperature range to prevent early cracking failure. At the same time, it should be ensured that there are no problems with internal factors before the mold is put into production and during production. Because in actual production, most mold failures are failures caused by thermal fatigue cracks.

2. Fragmentation failure

Under the action of pressure, the mold will crack at the weak place, especially if the scribe marks or electrical machining marks on the molding surface of the mold are not polished, or the clear corners of the molding will appear micro cracks first. When there is a brittle phase or coarse grains in the boundary, it is easy to fracture. However, the cracks expand rapidly during brittle fracture, which is a very dangerous factor for the chipping failure of the mold. For this reason, on the one hand, all scratches and electrical machining marks on the mold surface must be polished, even if it is in the gating system part, it must be polished. In addition, the mold materials used are required to have high strength, good plasticity, good impact toughness and fracture toughness.  

3. Dissolution failure

Commonly used die-casting alloys include zinc alloy, aluminum alloy, magnesium alloy and copper alloy, as well as pure aluminum die-casting. Zn, Al, and Mg are more active metal elements, and they have a good affinity with mold materials. When the hardness of the mold is higher, the corrosion resistance is better, and if there are soft spots on the molding surface, the corrosion resistance is unfavorable.  

What are the effects of mold temperature on injection molding?

1. The influence of mold temperature on injection molding

1. Mold temperature is a variable in injection molding. No matter what kind of plastic is injected, it is necessary to ensure that the surface of the mold is basically wet. The hot mold surface keeps the plastic surface liquid long enough to build pressure within the cavity. Reproduction of the cavity surface is high if the cavity is filled and the cavity pressure can press the soft plastic against the metal before the frozen skin hardens. On the other hand, if the plastic entering the cavity at low pressure is suspended, no matter how short, its slight contact with the metal can cause smearing, sometimes called gate smearing.

2. For each plastic and plastic part, there is a limit on the surface temperature of the mold, beyond which one or more adverse effects may occur (for example: components can overflow burrs). Higher mold temperatures mean less resistance to flow. On many injection molding machines, this naturally means faster flow through gates and cavities, since the injection flow control valve used does not correct for this change, faster filling results in higher efficiency in sprues and cavities pressure.

3. It may cause flash burrs. Since the hotter model does not freeze the plastic that entered the flash edge area prior to high pressure buildup, the melt can flash around the ejector pin and spill into the parting line gap. This shows the need to have good injection rate control, which some modern flow control programmers do.

4. The increase in mold temperature will reduce the condensation layer of plastic in the cavity, making the molten material flow more easily in the cavity, resulting in greater part weight and better surface quality. At the same time, the increase in mold temperature will also increase the tensile strength of the part.  

What are the main reasons that affect the machining accuracy of molds?

1. What are the main reasons that affect the machining accuracy of molds?

1. Dimensional accuracy

It refers to the consistency between the actual size of the processed part and the center of the part’s dimensional tolerance zone. Dimensional accuracy is controlled by dimensional tolerances. Dimensional tolerance is the allowable variation in part size during cutting. When the basic dimensions are the same, the smaller the dimensional tolerance, the higher the dimensional accuracy.

2. Shape accuracy

Refers to the consistency of the actual geometry and ideal geometry of the surface of the part after machining. Items for evaluating shape accuracy include 6 items such as straightness, flatness, roundness, cylindricity, and line profile. Shape accuracy is controlled by shape tolerance. Except for the 13 precision grades of roundness and cylindricity, each shape tolerance is divided into 12 precision grades, and the rest are divided into 12 precision grades. Level 1 is higher, level 12 is lower.

3. Position accuracy

Refers to the actual position accuracy difference of the relevant surface of the part after machining. Items for evaluating position accuracy include parallelism, perpendicularity, inclination, coaxiality, symmetry, positional degree, circular runout, and full runout. Position accuracy is controlled by position tolerance, which is also divided into 12 accuracy levels for each item.

4. Relationship between dimensional accuracy, shape accuracy and position accuracy

Usually, when designing mechanical parts and specifying the machining accuracy of the parts, attention should be paid to controlling the shape error within the position tolerance, and the position error should be smaller than the dimensional tolerance. That is, the important surface of precision parts or parts should be higher than the positional accuracy, and the positional accuracy should be higher than the dimensional accuracy.   

How to identify the advantages and disadvantages of incoming mold materials during mold design and processing?

Second, uneven

B. The appearance of fake and inferior mold materials often has pockmarked surface. The pitted surface is the irregular unevenness on the surface of the incoming mold due to the serious wear of the rolling groove. Because the manufacturers of counterfeit and shoddy molds want to pursue profits, the rolling of the grooves often exceeds the standard.

3. Material

C. Fake and inferior molds are prone to scarring on the surface of incoming materials.

1. The material of the fake and inferior mold is uneven and there are many impurities.

2. Fake and inferior materials have simple equipment and are easy to stick to steel. These impurities are prone to scarring after biting the roll.

4. Cracks

D. The surface of the fake and inferior material is prone to cracks, because its blank is adobe, and the adobe has many pores, and the adobe is subjected to thermal stress during the cooling process, resulting in cracks. After rolling, there are cracks.

5. Scratch

E. Fake and inferior mold materials are easy to be scratched, because the fake and inferior materials manufacturers have simple equipment, which is easy to produce burrs and scratch the surface of mold materials. Deep scratches reduce the strength of the incoming mold.  

How to choose stamping and drawing die materials?

1. Selection of drawing die materials

1. The selection of stamping and drawing die materials should consider the batch production of the workpiece. If the batch is small, there is no need to choose a mold material with a long life; the material of the stamping workpiece should also be considered, and the mold materials suitable for different materials are also different.

2. For stamping and drawing dies, wear resistance is an important factor determining the life of the die. The wear resistance of steel depends on the state of hard spots such as carbides and the hardness of the matrix. The higher the hardness of the two, the higher the number of carbides, the better the wear resistance.

3. The advantage of poor wear resistance of commonly used stamping die steel is carbon tool steel – alloy tool steel – base steel – high carbon and high chromium steel – high speed steel – steel bonded carbide – carbide.

4. The selection of the drawing die material must consider the thickness, shape, size and precision requirements of the workpiece.  

Well, the above is related to the selection of stamping and drawing die materials. I hope the above content can help readers.

What are the forms of stamping and drawing dies?

1. The form of stamping and drawing dies

1. Formal features

The surface of the punched workpiece is relatively flat to provide conditions for our subsequent processing.

2. Flip-chip features

It is very convenient to operate and has a wide range of applications, but the flatness of the workpiece surface is relatively poor, and the tension on the punch and die is relatively large, so the wall thickness of the punch and die should be strictly controlled to avoid insufficient strength.

After analysis, it is very inconvenient to operate the workpiece if it adopts a formal-type conforming mold. In addition, the workpiece has higher straightness requirements and relatively low workpiece accuracy requirements, so it is easy to operate. Considering the simplicity of mold manufacturing and other aspects, it was decided that the second, third and fourth deep drawing should be inverted, and the first deep drawing should be formal.

Through the above introduction, we can understand that there are two forms of stamping and drawing dies, which are formal and inverted, and different forms should be selected according to different production processes.

How to choose the positioning method of stamping and drawing dies?

1. Blocking pin

The function of the stopper pin is to use the strip to overlap or punch the outline to limit the feeding distance of the strip. There are three common types of stopper pins in national standards: fixed stopper pins, movable stopper pins, and initial stopper pins. The fixed stopper pin can be easily installed on the bottom die and can be used to control the feeding distance of the strip. It features simple structure and convenient processing. Because it is installed on the die, the mounting hole may also weaken the strength of the die, and the commonly used structures have similar circular and hook-shaped retaining pins. Active stop pins are often used in flip-chip composite molds. The start stop pin is used to start positioning in the progressive die.

Second, the guide pin

Guide pins are often used in conjunction with stop pins in progressive dies to minimize positioning errors and ensure the relative position dimensional accuracy requirements of holes and shapes. When there is no hole suitable for the guide pin on the part, for the progressive die with too many processing steps and high part accuracy requirements, process holes should be set in the vacancies on both sides of the strip to guide the pin. Use straightening strips. At this time, the guide pin is fixed on the punch fixing plate or the elastic pressure stripper.

Three, side edge

In the progressive die, the side edge is often used to control the step distance of the strip, so as to achieve the purpose of accurate positioning. The side edge is actually a punch for cutting edge material, using the edges on both sides of the side edge to cut off the material on both sides of the strip to form a step. After the strip is cut off part of the edge material, the width can continue to be fed to the die, and the feeding distance is the cut length. When the material is sent to the step formed after cutting, the side edge stopper prevents the material from continuing to feed, and a new feeding step can be formed only after the next work of the mold.

Fourth, the positioning plate and positioning nails

Positioning plates and positioning pins are all components used for positioning a single blank to ensure the relative position accuracy of the front and rear processes or the position accuracy requirements of the inner hole and outer contour of the workpiece.

5. Control of feeding direction

The feeding direction of the strips is the guide plate with the strips on the side, and the feeding is guided along the designed feeding direction to make the strips close to the guide plate on one side to ensure the accuracy of the feeding, and a side pressure device can be used. Since the stamping and drawing die adopts the cover-shaped semi-finished product that is drawn out of the sheet for the first time, the material can be positioned by the blank holder in the die.

The editor added: The correct position must be accurately guaranteed by relying on its own positioning parts. Due to the different forms of blanks and the different structures of the stamping and drawing dies used, there are many types of positioning parts. The design should be selected according to the form of the blank, the structure of the stamping and drawing die, the tolerance of the parts, and the production efficiency.

Through the above introduction, let’s briefly introduce that we have a good understanding of the positioning of the stamping and drawing die, and the selection of its positioning method is selected according to the positioning parts, which I hope we can understand.

How to solve the rust of the drawing die

First, the cause of mold rust

There are three main reasons for mold rust:

1. The product of the decomposition of the molding material.

2. The resurgence of molds.

3. Sweaty hands.

Second, the relevant analysis of mold rust

1. The products (gas, residue) decomposed by the forming material are also very common to the corrosion of the mold. In order to prevent the mold from rusting, we generally use chrome plating on the mold cavity, but the chrome plating treatment cannot completely solve the problem. Because decomposing organisms also corrode the deep part of the pin hole. And these places are places where there is no way to plate them.

2. When the mold is cooled below the moisture regain point, the moisture in the air will regain moisture on the mold surface and produce water droplets, which will lead to rust.

3. Solve the problem of mold rust

1. Short-term: wipe the surface of the mold cavity with a cloth by hand. Fully dry the molding material, reduce the temperature of the barrel, and prevent the material from decomposing. When temporarily stopping molding, spray rust inhibitor into the mold cavity, and then close the mold.

2. Long-term: Turn the product material into a material that will not be corroded by decomposition products. Materials that are easily decomposed include PVC, POM, EVA, PC, and foam. Since the decomposition products have a corrosive effect on the mold, if the plastic raw material cannot be replaced, the mold should be chrome-plated. When the mold is not used for a long time, apply a layer of butter to the outside of the mold and the movable parts.

What are the differences in the manufacture of stamping dies?

First, the manufacturing difference of stamping dies

1. Different smelting process

The smelting process of Dachang material is electric furnace smelting, out-of-furnace refining, and vacuum degassing. The chemical composition of the steel in this process is accurately controlled, the gas content in the steel is low, and the steel purity is high. The materials of small factories are generally mixed scrap and furnace materials in the intermediate frequency furnace, and the flat steel ingots are directly poured. The chemical composition deviation of this process is large, the impurities in the steel are large, and the gas content is high, resulting in more shrinkage cavities and internal cracks in the finished product, which seriously affects the processing performance of the steel.

2. The rolling process is different

Dachang’s steel ingots are forged into billets and then rolled into products. During the rolling process, multiple rolling mills and multiple deformations are used for continuous rolling. Small mills are steel ingots that are directly rolled back and forth by a single rolling mill. The ingot deformation is small, the rolling ratio is small, the internal microstructure is uneven, and the non-metallic inclusion particles are large. It is directly manifested as the local “saw and drill” of the material.

3. Different appearance quality

Since the material of the big factory is continuously rolled, and the number of deformations is large, the precision of its appearance and size is high, and the two sides are approximately right angles. Because the production process of the small factory material is all controlled manually, its appearance size deviation is large, the thickness and width tolerance is large, the flat steel fillet is large, and the cross-section deviates from the rectangle.

4. Different heat treatment methods for finished products

After the material of the big factory is finished, the global annealing process is adopted to ensure that the carbide grade in the steel is not greater than grade 4, and the uniformity of hardness is ensured. Small factory materials adopt general softening annealing process, even natural cooling, which cannot guarantee the uniformity of carbide grade and hardness in steel.

5. The effect is different

Due to the different production processes, it directly affects the use effect of materials. First of all, the material size deviation of the small factory is large, and the straightness is relatively poor, resulting in a large enough machining allowance during processing, otherwise it cannot be processed. Secondly, due to the uneven hardness of materials in small factories, it is difficult to process and punch holes, and the processing efficiency is low. After processing, the workpiece is easily deformed, and even the mold is scrapped.