How to reflect the processing quality of metal stamping parts?

1. What are the aspects of the processing quality of metal stamping parts?

1. Chemical analysis, metallographic examination

Analyze the content of chemical elements in the material, determine the particle size level and uniformity of the material, evaluate the level of free cementite, banded structure and non-metallic inclusions in the material, and inspect the material for defects such as porosity.

2. Material inspection

The materials for stamping parts are mainly hot-rolled or cold-rolled (mainly cold-rolled) metal sheet and strip materials. The raw materials of metal stamping parts should have quality certificates to ensure that the materials meet the specified technical requirements. When there is no quality certificate or other reasons, manufacturers of metal stamping parts can select raw materials for re-inspection as needed.

3. Formability test

Perform bending test and cupping test on the material to determine the work hardening index n value and plastic strain ratio r value of the material. In addition, the test method for the formability of the steel plate can be carried out according to the provisions of the formability and test method of the thin steel plate.

4. Hardness test

The hardness test of metal stamping parts adopts Rockwell hardness tester. Small stampings with complex shapes can be used for small test planes and cannot be tested by ordinary desktop Rockwell hardness testers.

5. Measurement of other performance requirements

Determination of electromagnetic properties of materials and adhesion to coatings and coatings.

The technical requirements for processing metal stamping parts are shared with you here. In addition, it should be noted that the accuracy and surface condition of hot metal stamping parts are lower than those of cold metal stamping parts, but they are still better than castings and forgings, and the amount of machining is less.

How to assemble the stamping continuous die?

1. How to install the stamping die?

1. Confirm whether the blanking hole of the die and the blanking hole of the pad are consistent.

2. After the upper and lower dies are assembled, put them on the lower table, and ensure that the datum plane of the punch and the datum plane of the mold are parallel.

3. The lower mold should be completely fixed, and the upper mold should be lightly fixed in advance.

4. Test the slider on the punching machine for 20-30 times. After confirming that the upper and lower dies are in complete agreement, tighten the upper dies.

5. The bite component of the punch and concave die is combined with the lower die stopper of the die to adjust the height of the slider on the punch press.

6. Use the test punch of the sealing paper to confirm its cutting condition. If it is not uniform, check the installation state of the mold again. If the consistency cannot be achieved, it is necessary to confirm the parallelism of the punch slide and the lower table of the punch.

7. Adjust the material feeding length and feeding time. (If a scrap cutter is attached, the length of the material to be fed can be confirmed by the length of the cut scrap)

8. Comprehensive operation for 3-5 minutes. During this period, oil should be filled between the guide column and the bushing, and it should be confirmed whether there is any abnormality in the heat.

9. Try on the selected material to be processed to confirm that there is no obstacle in the insertion.

10. After the above work is completed, processing can be carried out. First, press down the first material positioning rod set on the side of the lower die, and feed the material until it touches the positioning rod. After insertion, the test punch is first hand-fed until the end of the final process.

11. After confirming that there is no abnormality in the hand feeding type, close the switch of the punch feeding device. At this time, the feeding work needs to be carried out completely on the finished position.

12. The punching die uses a single punching motion to confirm whether the feed is appropriate.

2. What is the mold assembly to do?

1. Select the assembly reference parts. When assembling, first select the reference part. The principle of selecting reference parts is determined according to the dependence of the main parts of the mold during processing. The main components that can be used as assembly reference parts are punches, punches, punches and punches, guide plates and fixed plates.

2. Component assembly. Component assembly refers to the assembly work in which two or more parts are connected into a component according to the specified technical requirements before the final assembly of the mold. Such as the assembly of the mold base, the assembly of the punch and the concave mold and the fixed plate, the assembly of the parts of the unloading and pushing mechanism, etc. These components should be assembled according to the functions of each part, which will play a certain role in ensuring the assembly accuracy of the entire stamping die.

3. Overall assembly. Final assembly is the process of combining parts and components into a complete stamping die. Before final assembly, the reference parts for assembly should be selected and the assembly sequence of the upper and lower dies should be arranged.

4. Adjust the gap between convex and concave die. When assembling the mold, the uniformity of the gap between the convex and concave molds must be strictly controlled and adjusted. After the gap is adjusted, the screws and pins can be tightened. The methods for adjusting the gap between the convex and concave molds mainly include the light transmission method, the measurement method, the gasket method, the coating method, and the copper plating method.

5. Inspection and debugging. After the stamping die is assembled. The assembly accuracy must be guaranteed, the specified technical requirements must be met, and the function of each part of the mold must be inspected in accordance with the technical conditions for mold acceptance. Test the mold under the actual production conditions, and adjust and correct the mold according to the conditions of the test mold production parts. When the mold test is qualified, the mold processing and assembly are basically completed.

6 considerations for stamping continuous die design

1. Punching waste should not be ejected

When designing continuous molds, the discharge of scrap is as important as the conveying of the coil. The timely and reliable discharge of punching waste from the mold is the basis for ensuring the normal production efficiency of continuous molds. For fine blanking dies, punching waste cannot leak from the die hole, but can only be ejected from the die surface.

2. The depth of the hole for the float pin of the discharge plate in the continuous die should be reasonable

When the part material is thin, the height position of the floating pin should match the depth of the breakaway hole of the stripper. If the escape hole of the stripper plate is too deep, the material will be bent upwards under the action of the compression spring force, and the material will not be able to be fed normally; if the escape plate of the stripper plate is too shallow, the material will be cut off. Therefore, the depth of the hole for the floating pin of the stripper plate in the continuous mold should be reasonable.

3. The continuous die should not have positioning devices such as stoppers and side blades

For the continuous die stamping workpiece, it is necessary to solve the problem of accurate positioning of the strip material and ensure that the step distance of the continuous die is consistent so that qualified parts can be punched out. Commonly used positioning devices include fixed baffle pins, guide plate pins, guide plates, and side blades.

Fourth, the position of the side edge in the continuous die cannot be ignored

Side edge positioning can accurately control the step distance and has high positioning accuracy, but it needs to cut one or both sides of the material, resulting in waste and waste. When using the side edge distance, the side edge position should be appropriate.

5. The shape of the side edge in the continuous die cannot be ignored

There are three side edge shapes in continuous die: rectangular flat side edge, L-shaped side edge and concave side edge. The rectangular flat side edge is easy to make, but it is easy to produce burrs. The L side edge affects the feeding, and the concave type does not affect the feeding, but it increases the manufacturing difficulty of the side edge.

Six, the continuous mode guide pin should not be too long

In order to control the feeding step, continuous molds need better positioning devices. Among them, the guide pin is a precise positioning method widely used in continuous molds. It should be noted that the length of the guide pin should not be too large, and the length of the guide hole should not be too large, otherwise it will break due to insufficient rigidity.

Metal stamping continuous die layout technology

1. Design principles of continuous stamping layout drawing

Before blanking of flat blanking parts (including flat blanks of various forming stamping parts – the same below), in order to save materials, economical and reasonable arrangement is carried out on plates, strips, strips and coils to obtain the best samples and achieve the best possible results. Possible high material utilization. In the cold stamping process design and die design, this is an important and technical work; in the cold stamping die structure design, the stamping part drawing, stamping process and its sample drawing are the main basis.

In the known professional publications, the layout of single-station blanking dies and composite die-stamping parts is introduced in detail, and the layout of multi-station continuous die-stamping parts is not involved.

The layout drawing of multi-station continuous stamping parts should fully explain the stamping process and the sequence of stamping steps, and indicate the feeding distance, the specific data of edge extension and edge overlap, the feeding method between stations, and all stamping processes and deformations of stamping parts. and separation process.

Die selection, structural design, stamping material utilization η, stamping productivity are closely related to the production cost of stamping parts, but also affect the quality of stamping parts and die life. The layout should fully consider the material supply and the production conditions of the stamping equipment. On the basis of ensuring the stamping quality, efforts should be made to make the stamping die have better structure, better operational safety and die technology, and comprehensively analyze the various factors that affect the layout. Factors, compare multiple schemes, and choose the best layout.

Before the die stamping design begins, the die stamping drawing and layout drawing should be analyzed to understand its main technical requirements and stamping difficulties, and lay the foundation for the die stamping structure design according to the rationality of the die stamping process and possible problems.

Among the many single-process dies, only blanking dies and single-station composite dies need to design layout drawings. That is to say, when blanking (blanking) flat blanks and forming stampings to develop flat blanks, nesting is required. And most of them are conventional nesting methods with scrap blanking along the edge, and most of them can only achieve less scrap blanking. Regardless of the layout method used, the rationality and advantages and disadvantages of layout are generally measured by the material utilization rate.

The layout of continuous die-stamped parts is different from the above. Material utilization η is not the most important and only criterion for measuring the quality of nesting.

For the layout of continuous die stamping parts, it is necessary to analyze the stamping process, reasonably design the stamping process and the sequence of the stamping process, fully consider the characteristics of the continuous stamping process and the needs of the stamping structure design, and pay attention to the feeding and inter-station feeding methods. selection and design of positioning systems.

Therefore, the layout of continuous die stamping parts is based on the design of continuous stamping process steps, with the core of ensuring the quality of stamping parts and the accuracy of size and shape, and the sequence arrangement of stamping steps and the selection of the feeding method between stations are as follows: Pilot, for the purpose of die selection and structural design, the basic principles that should be followed are as follows: 

(1) It is beneficial to choose a simpler type and structure of punching die, and its operation is safe and the quality of punching parts is good.  

(2) The manufacturing process of the die is good, the grinding is convenient, the molding cycle is short, and the cost of molding and repairing is low.

(3) The plate utilization rate η value is high.  

(4) The mold life is longer.  

(5) The stamping efficiency is higher, and the production cost of stamping parts is lower.

Among the above five articles, article (1) is the primary one.

Sometimes it is impossible to have both, the user’s requirements and delivery time should be considered first, and other terms can be appropriately relaxed. In many cases, higher material utilization η tends to complicate the structure of the die, making the die more difficult, and even difficult to manufacture with the existing die-making equipment and technical level, no matter how good the layout and the higher the η value. , and must also be abandoned; some would rather reduce the utilization rate of the plate η to obtain better molding processability, shorter molding cycle, and higher mold life.

2. Selection of layout form and its relationship with die type and structure

For blanking dies and composite dies with only one station, the layout methods of flat blanking and various forming blanks on plates, strips, strips and coils are usually: single row, straight row, Single row oblique row; double row parallel row, double row head-to-head row, double row head-to-head oblique row; multi-row row, staggered row and mixed row, etc.

Different nesting methods obtain different material utilization rates, and the choice of different nesting methods should first consider the size and shape accuracy of the punching parts, and then decide to choose the appropriate type of punching die and its structure.

If the dimensional accuracy of punched parts is required to be above 1t10 level, the layout method with edge and overlap should be adopted; the dimensional accuracy of punched parts without overlap layout is poor, generally below 1t12 level, or even as low as 1t14 level. If the dimensional accuracy of the punching piece is as high as 1t9 or higher and the punching piece is required to be straight, a punching die with a sliding guide column die set with a spring-loaded stripper structure should be selected, and its layout should be given enough edge and overlap.

According to the German Industrial Standard din1543, the cold stamping steel plate is classified according to the thickness t: t<3mm is a thin plate.

In the production of products in the instrumentation and electronic industries, ultra-thin foil stamping parts with t≤0.3~0.1mm or even ≤0.1~0.05mm are often used, which brings many difficulties to stamping layout and die design.

Because the edge of the nesting, the width of the overlapping edge and the size of the blanking gap all increase or decrease with the thickness t of the blanking material.

When t≤0.5mm, the width of the lap and edge should be greater than t so as not to be pulled into the die hole during punching, and to make it have sufficient strength and ensure that the lap frame has a good feeding rigidity; t= 0.3mm low carbon steel plate, according to the class I gap stipulated by gb/t16743-1997 “Blanking Gap” Internationally, 3%t can be taken as the unilateral gap of punching die c=3%×0.3mm=0.009mm, t=0.1mm then c=0.003mm, which is 3μm. And gb/t2854-90 international grade I sliding guide guide column die set stipulates the guide column guide sleeve matching clearance is 0.010 ~ 0.016mm. Therefore, when the above-mentioned ultra-thin material is punched and continuously punched, special attention should be paid to selecting a suitable layout method and designing a reasonable and precise mold structure, otherwise it will be difficult to complete the punching of such punching parts, and it is impossible to meet the requirements. Dimensional and geometric accuracy.

For continuous stamping and forming of ultra-thin punching parts with t<0.5mm, the width of the overlapping edge and the edge of the layout can be the same, and it can be appropriately enlarged according to the needs of the die structure design. In terms of the selection of die structure type, it is recommended to select the guide column die frame elastic pressure unloading guide die, and it is best to install the elastic pressure guide plate on the guide column and install a small guide column on the discharge plate (guide plate) to ensure the elastic pressure discharge. The guide plate type punching die has precise guidance and improves the punching accuracy of the punching die; the coaxiality and position of the punching group holes put forward higher requirements on the accuracy of the layout and feeding distance and the feeding and positioning of the punching die. Special attention should be given to layout.

Ultra-thin punching parts with material thickness t≤0.1mm, especially complex-shaped punching parts formed by multiple stations and one die, should not use multiple rows of oblique rows, facing rows and turning punches, and it is even more unsuitable to use mixed rows. Otherwise, the frame will be easily deformed, broken, or even pulled into the die during feeding, which will affect production, increase scrap products, and damage the mold; for medium and heavy plate punching with a material thickness of t≥3mm, cutting and stacking layout is not recommended. , t ≥ 4.75mm, it is not recommended to use nesting and cutting layout. Otherwise, it will bring difficulties to the structural design of the mold.

For high-precision foil stampings with dimensional accuracy ≤±0.01mm and material thickness t≤0.1mm, especially for stampings with complex shapes with a precision higher than 1t9, it is recommended to use a ball-guide-pillar die-base elastic-pressure unloading guide-type die structure.

Layout drawing design points The layout drawing design of single-station blanking die and compound die is to expand the shape of flat blank according to flat blanking parts and three-dimensional forming parts, and repeatedly arrange them on strips and strips to ensure the quality of punching parts. In the case of production efficiency and process requirements, the die structure is simpler, the mold making is more convenient, and the highest possible material utilization rate is the criterion, and a better layout method is selected. Under normal circumstances, the shape and size structure of the blanking parts determine the type of layout, and most of them need to use the traditional layout method with edge and overlap to carry out blanking with waste.

According to many years of practical experience, for the design of the layout drawing of single-process blanking and composite punching and single-station integrated composite stamping, it can be considered as a single blanking of flat blanks and three-dimensional forming parts. Compared with single punching die, the layout of continuous die punching parts is much more complicated. The layout should ensure the smooth implementation of the continuous punching process and obtain the highest possible η value. The operation is safe, the efficiency is high, there are many influencing factors, and the requirements are high. The steps and key points are as follows:

(1) After a detailed process analysis of the stamping parts, the feasibility of continuous stamping and one-die forming of the stamping parts is studied, and a number of stamping process schemes are proposed for comparison, and the layout is implemented after selecting the best ones.

(2) The shape, size and accuracy of the stamping directly affect the continuous stamping process and the sequence of the steps. When laying out the layout, the manufacturability of the continuous stamping and the needs of the die structure design should be considered, and attention should be paid to the sequence of the steps and the arrangement of the stations. The following points:

a. The holes in the group of holes on the punching piece whose hole spacing accuracy is required to be above 1t10 or the hole spacing tolerance value is less than 0.01mm should be punched out in one or two adjacent stations;

b. If the hole wall and hole edge of the punched part are smaller than the material thickness t or less than 2mm, they should be punched out in two stations in steps to enhance the strength of the die and expand the installation position of the punch on its fixing plate;

c. For the coaxiality and position of the group holes, the requirements are very high, and the tolerance is less than 0.01mm. The relevant holes can be punched out at one time or in two adjacent stations. The parts that require smooth punching and punching should be concentrated. Implemented at one or two stations;

d. If the shape of the punched part and the size tolerance of the formed part are very strict, the overall blanking can be considered and then bent or deep drawn; if the size of the local boss or notch of the punched part is strict, it can be punched separately by multiple stations. post splicing;

e. For small and complex shaped stampings with large output, multi-station continuous stamping and one die should be used as much as possible to improve the quality and efficiency of stampings; 

f. The dimensional accuracy requires high-precision punching parts above 1t10. When laying out samples, the number of steps should be minimized to prevent the number of stations from being too large, the accumulation of feeding errors will be large, and the punching accuracy will be reduced. Partial fine punching, upsetting extrusion, flattening, etc. should be Arrange special work stations; 

h. For punching parts with complex multi-directional bending, lateral punching and incision that need to be punched with lateral force, consideration should be given to using wedge drive transverse punching to form after plane punching, incision or before blanking. Precision and Efficiency.

(3) Considering the requirements of the die structure design and the required position of the stamping deformation, set up the necessary neutral station, and increase the installation position of the punch on the fixed plate; Surface area, an empty station should also be added to increase the wall thickness of the die.

3. Layout type and method of continuous die stamping

According to the characteristics of the continuous die stamping process, the same feeding method of the station, whether the layout has overlapped edges, and the method of removing process waste, the layout of the continuous die stamping parts can be summarized into the following types and layout methods:

1. Slitting and combining layout

Each station punches and forms a part of the punching piece respectively. Each station is relatively independent and independent of each other. Its relative position is controlled by the die, and finally combined into a complete and qualified punching piece, see Figure 1a), b), f), j).

2. Piece and cut combination layout

The inner hole and shape of the punching piece, even a complete blanking line of any shape, are punched separately by several stations, and finally assembled into a complete punching piece. Although it is similar to the slitting combination, it is not the same. The combination of each station and the cutting edges are related to each other, and the interface parts must overlap, which increases the difficulty of mold making.

3. Cutting edge layout

The complex shape of the side of the punched piece is obtained by the method of punching along the edge, that is, the cutting edge layout. When the length l of the punching edge in the feeding direction is equal to the feeding distance s, that is, l=s, the punch can replace the side edge and undertake the task of cutting the edge of the fed raw material. This type of side punch is commonly referred to as a forming side edge. Because jb/t-76481-94 has few standard side edge varieties and limited size specifications, the maximum cutting edge length is only 40.2mm. When the feeding distance s>40.2mm, only non-standard side edges can be used.

Another disadvantage of using a standard side edge is that it is necessary to cut a certain width of material on the side of the raw material to form an incision with a length equal to the feeding distance. Positioning the feeding raw material increases the process waste and reduces the η value by 2% to 3%. %. Using the side punch to cut the edge can not only complete the blanking of any complex shape of the side profile of the punching piece, but also realize the limit of the feeding distance of the raw material, instead of the standard side edge, which serves multiple purposes.

4. Cut and overlap the layout

For slender and thin blanking parts, long blanking parts with complex contours to be blanked at the part connected to the lap edge, can obtain high-quality and high-yield effects by laying out the lap edge, which can avoid slender blanking parts Disadvantages such as distortion and difficult unloading. The more typical punching parts are instrument hands, watch second hands, etc. The above cutting edge layout is used, and the effect is very good. For the convenience of molding, sometimes the edge is enlarged to facilitate blanking, and the edge is left on the raw material as a punch. The pieces are finally cut and separated.

5. Combined punching and nesting along edge and overlapping edge

Step by step punching the edge and lap by sub-station, to obtain the layout of the formed punching blank and punching and forming, which is called the combined punching layout of the edge and the lap. The process wastes are washed away at each station, and the punched parts are left on the raw materials and gradually formed until the final station is separated. This type of layout can keep the stations on the same plane and arrange them in a straight line along the feeding direction. The raw materials are used to carry the workpieces into place between the stations. The mold structure is simple, and the operation is convenient and safe.

6. Nesting layout

Use the structural waste of the inner hole of the large-sized punching piece to punch the smaller-sized punching piece of the same material in the special station of the same set of continuous molds, that is, the nesting layout.

Under normal circumstances, the small-sized punching parts in the inner hole are punched first, and the large-sized punching parts are often punched out at the last station.

The nesting of gaskets with a single-station composite blanking die is a typical nesting layout that has been known for a long time. For the nesting layout of multi-station continuous blanking parts, because the upper and lower stations have no overlapping edges, the coaxiality is required to be high, and the feeding distance must be small to ensure the size and shape accuracy of the nesting blanking parts.

7. Layout layout

Using the process waste of the punched parts and the structural waste connected along the edge, the punching parts of the same material are spliced ​​and punched together, that is, the layout is cut out. The difference from nesting and layout is that stenciling is to make the best use of process waste or excess edge and overlap, as well as the outer edge structure waste generated due to the complex shape of the punched parts and the large difference between convex and concave. The punching material is the same. Various punching pieces. When laying out samples, make full use of the convex and concave parts of the shape of the punching parts, and insert forks into each other to make full use of the raw materials.

No lap layout and no-waste blanking Since most of the continuous die-stamping parts use edge and lap layout, only blanking with waste can be carried out. If the layout without edge and edge can be carried out, and the blanking part has no structural waste, it can be blanked without waste. Completely scrap-free blankings that truly achieve 100% or near 100% sheet utilization are rare. Any punching that can be used for layout without overlapping can be punched with less waste.

In order to implement the blanking of blanking parts with no waste and less waste, it is first necessary to carry out the layout of blanking parts without overlapping edges.

There are certain conditions and methods for the implementation of no-overlap nesting. In addition to the above-mentioned continuous die-punching parts, which can be used for layout without overlapping edges and blanking with no waste or less waste, single-process punching dies and single-station composite punching dies can also do the same.

4. Non-linear feeding continuous composite die-stamping method

The feeding direction of most continuous molds is carried out along a straight line on the same plane, and the feeding of each station is carried out by feeding raw materials. For this reason, the punched parts are always kept on the raw materials with lap edges for stamping processing at each station. The finished punching piece connected with the lap edge cannot be separated from the raw material until the processing is completed to the last station. For some punching parts with large flange heights, large drawing heights and complex shapes that require multi-directional force bending, it is often necessary to blank them as a whole and then form them on another set of punching dies.

Otherwise, the punched part can be taken out from the die cavity because the die needs to have a large opening height. If the conventional continuous die is used to arrange the stations in a straight line on the same plane along the feeding direction, it will be difficult to design the die structure.

This type of punching piece is formed by a multi-station continuous die, and its layout method is completely different from the above-mentioned conventional continuous die layout. The blanking blank is pushed to the forming station at a certain angle to the feeding direction of the raw material, and is bent or deep drawn. Make the stations of the die arranged in an L shape, and the stations are not on the same plane

With the rapid development of modern stamping technology, the continuous improvement of stamping mechanization and automation, and the improvement of stamping safety production requirements, continuous dies of this type of structure will be increasingly widely used.

The three-station continuous composite die for lifting ring punching parts, the first station punches rectangular holes, the second station is blanking, bending and compound punching, and the third station is a feeding system driven by the wedge of piece 8. After the curved workpiece at the second station is pushed into place along the bending core piece 12, the two sets of 13 cam drive mechanisms are used to exert force opposite and perpendicular to the feeding direction to push a pair of forming die pieces 17, and the stamping workpiece is finally formed. The die has both the action characteristics of a continuous die and the function of a composite die. Since the second to third stations are formed by separating the workpiece from the raw material, it is not realistic to call the progressive die;

Calling a continuous die ignores the function of the second station compound stamping and the separation and deformation of the entire die and the characteristics of the compound stamping, so it is more appropriate to name it a continuous compound die.

The continuous composite die adopts staggered double rows and straight rows. After the overall blanking, the unrolled blanks are pushed to both sides and bent at the third station. The production efficiency is high and the punching quality is good. This type of automatic or semi-automatic continuous compound die is safe to operate, and will be used more and more with the diversification of coil supply varieties and specifications.

Talking about the influence of the necking process in the processing of metal stamping parts

In the process of shrinking, the metal stamping material at the shrinking end slides into the die under the pressure of the punch to reduce the diameter and increase the wall thickness and height. It can be approximated that the deformation region is in a state of plane stress under positive pressure in both tangential and radial directions, and the tangential pressure is the main force. The radial compressive strain is the maximum strain, while the thickness and length directions are elongation deformation, and the deformation amount in the thickness direction is more than that in the length direction.

Due to the action of tangential compressive stress, the billet is easily unstable and wrinkled during the shrinking process; at the same time, the wall of the non-deformed area is also prone to instability and deformation due to all the shrinking pressure. Therefore, preventing instability is shrinking. The main problem with the process.

The ultimate deformation degree of the necking is mainly limited by the buckling conditions. The degree of deformation of the necking depends on the necking coefficient of the material. It is expressed by the total shrinkage coefficient ms:

ms = d/D     where

ms—total shrinkage coefficient, d—diameter after shrinkage; D—diameter before shrinkage.

The size of the shrinkage coefficient is related to the mechanical properties of the material, the thickness of the material, the form of the mold, the surface quality, the edge of the shrinkage end of the part and the lubrication conditions. The comprehensive mouth coefficient of various materials can be obtained through the relevant information table.

What are the factors that affect the dimensional accuracy of metal stamping parts?

The dimensional accuracy of metal stamping parts refers to the difference between the actual size and the basic size of the stamping parts. The smaller the difference, the higher the dimensional accuracy of the metal stamping parts.

1. The factors affecting the dimensional accuracy of metal stamping parts are as follows

1. Manufacturing accuracy of metal stamping die.

2. The gap of the concave and convex die.

3. The resilience of the material after stamping.

4. Accidental factors in the production process, such as inaccurate positioning, unstable material properties, etc.

5. It can be divided into precision grade and ordinary grade. The ordinary level is the precision that can be achieved by economic means, and the precision level is the precision that can be achieved by stamping technology.

The surface quality of metal stamping parts shall not be higher than the surface quality of raw materials, otherwise it needs to increase the follow-up processing to achieve, and increase the production cost.

Second, the accuracy requirements of metal stamping dies

Many aspects of stamping processing have precision requirements, such as the assembly of metal stamping dies, because this will greatly affect the quality and service life of stamping dies, as well as the quality of formed stampings. So, what are the specific precision requirements for stamping die assembly? please watch the following part.

1. The parts of the stamping die should meet a certain mutual position accuracy, such as: axis, perpendicularity, inclination, parallelism, etc.

2. Fitting accuracy and contact accuracy: Fitting accuracy refers to the fit clearance or interference degree between the surfaces of the parts that cooperate with each other, such as the fit between the cavity and the core, the insert and the template hole, the guide post, the guide sleeve and the template. Contact accuracy refers to the degree of distribution between the contact area and the actual contact points, such as the uniformity of the contact points on the parting surface, the contact area of ​​the locking wedge slope, etc.

3. The moving parts should meet the precision requirements of each mechanism such as rotation accuracy, rotary motion accuracy, and linear motion accuracy.

4. Guidance and positioning accuracy: such as opening and closing motion guidance, installation and positioning of cavity (concave mold) and core (punch mold), sliding motion guidance and positioning, etc.

5. Other precision requirements: for example, the vibration, noise, temperature rise and friction control of the stamping die during operation, as well as the tightening force, deformation, lubrication and sealing of the stamping die during assembly must meet the working requirements of the stamping die .

What are the commonly used steels for metal stamping dies?

2. Japanese plastic mold steel commonly used in the domestic market

G-STAR corrosion-resistant plastic mold steel, the manufacturer’s brand of Japan’s Datong Special Steel Co., Ltd. The steel can be pre-hardened, with a factory hardness of 33-37HRC, and has good corrosion resistance and machinability. It can be combined with S-STAR steel to form a corrosion-resistant plastic mold.

NAK55/NAK80 mirror plastic mold steel, Japan’s Datong Special Steel Co., Ltd.’s manufacturer’s brand. Both steels can be pre-hardened to a hardness of 37-43HRC. NAK55 has good machining performance, and NAK80 has excellent mirror polishing performance, which is used to make high-precision mirror plastic molds.

PXZ pre-hardened plastic mold steel, the manufacturer’s brand of Japan’s Datong Special Steel Co., Ltd. The factory hardness of the steel is 27-34HRC. The steel has good machining performance and welding repair performance, and is used to make large-scale etched molds and plastic molds such as automobile bumpers, instrument panels, and home appliance shells.

PX4/PX5 mirror plastic mold steel, the manufacturer’s brand of Japan Datong Special Steel Co., Ltd. The steel can be pre-hardened to a hardness of 30-33HRC. These two kinds of steel are American P20 modified type, which are used to make large mirror plastic molds and automobile taillights, front baffle molds, cameras, and home appliance shell molds.

S45C/S50C/S55C ordinary plastic mold steel. Japan’s JIS standard steel grades are similar to my country’s high-quality carbon structural steel 45, 50, and 55, which are often used in non-important parts of molds, such as mold bases. Due to the special requirements of mold steel, the production process of this type of steel requires concentrate, refining and vacuum degassing, the carbon content of the steel is narrowed, and the content of sulfur and phosphorus is controlled to a lower level. For example, in YB/T107-1997, carbon The steel grades of plain plastic mold steel are SM45, SM48, SM50, SM53 and SM55, etc., to distinguish them from high-quality carbon structural steel for general purposes.

S-STAR anti-corrosion mirror plastic mold steel, Japan’s Datong Special Steel Co., Ltd.’s manufacturer’s brand. The steel is a martensitic stainless steel with high corrosion resistance, high mirror polishing properties, and small heat treatment deformation. It is used to make corrosion-resistant mirror-surface precision plastic molds.

3. German plastic mold steel commonly used in the domestic market

GS-083, GS-083ESR, GS-083VAR, GS-083H, GS-083M, GS-128H, GS-162, GS-312, GS-316, GS-316ESR, GS-316S, GS-318, GS- 343EFS, GS-343ESR, GS-3615, GS-379, GS-711, GS-738, GS-767, GS-808VAR, GSW-2083, etc.

Material selection and characteristics and advantages of stamping die

1. Material selection of stamping die

The material types of stamping dies include steel, cemented carbide, steel-bonded cemented carbide, zinc-based alloys, low melting point alloys, aluminum bronze, polymer materials, etc. At present, the materials of stamping die are mainly steel, low alloy tool steel, high carbon and high chromium, medium carbon alloy steel, high speed steel, basic steel, hard alloy, steel bonded hard alloy, etc.

The material of the stamping die should have high hardness, strength and wear resistance, but also need appropriate toughness and high hardenability. In order to ensure the service life of mold products, it is necessary to select raw materials according to the use of molds, stress conditions, production batches, production efficiency and working conditions.

Second, the characteristics and advantages of stamping die

1. The number of parts completed by the stamping die per unit time is several times, even hundreds to thousands of times that of the general processing method. In addition, a set of dies can be stamped to further improve production efficiency.

2. The products produced by stamping die have the characteristics of stable quality, strong mechanical properties, compact structure, good interchangeability, good wear resistance, convenient maintenance and mass production.

3. The material utilization rate of the stamping die is high, and various layout methods such as cross, oblique, multi-row, mixing, and nesting can be adopted, which can reduce the cost of product materials.

4. Under normal circumstances, there is no need to heat the material during the stamping process, which not only saves energy, reduces the occupation of heating equipment and venues, but also avoids the oxidation, burns and deformation of the product surface caused by heating.

5. Stamping dies are widely used, which can solve the operations that cannot or are difficult to be completed by general processing methods, and are especially suitable for the processing of thin, soft, difficult and micro parts.

Finally, the processing process of stamping dies is very simple, the technical requirements for operators are not high, and the labor intensity is low. After receiving short-term job training, workers can start to operate. And during the operation, the basic movements of the workers are the same and are not affected by the complexity of the product.

How to choose the tolerance of precision metal stamping parts

Dimensional tolerances of formed stampings: The formed stampings are divided into 10 precision grades, represented by FT1 to ft10, where ft represents the dimensional tolerance of the formed stampings, and the Arabic numerals indicate the tolerance level. Accuracy class reduced from FT1 to FT10.

The limit deviation of stamping parts: the stamping deviation of the hole size is 0, the upper deviation is the lower deviation plus the dimensional tolerance; the upper deviation of the shaft size is the basic deviation, the value is 0, and the lower deviation is the upper deviation minus the dimensional tolerance. The upper and lower deviations of hole center distance, hole edge distance, bend, stretch length and height are half the dimensional tolerance.

Tolerance is the range of dimensional variation. The lower the value, the lower the precision and the less difficult the processing; the lower the value, the higher the precision and the more difficult the processing. So what are the important considerations in production:

1. Bending angle: the angular size of the stamping part formed by bending.

2. Blanking angle: the angle dimension formed by blanking on the plane of the flat or forming part.

3. Blanking fillet radius: the linear dimension of the fillet radius of the stamping part, the parts processed by the separation process such as stamping and blanking.

4. Forming size: the angular size formed by the bending linear dimension of the stamping part processed by stretching and other processes.

5. Blanking size: the linear size of stamping parts, used for stamping, blanking and other separation processes.

How to control the quality problems of metal stamping parts?

First, the main characteristics of metal stamping parts

1. Metal stamping parts are manufactured under the premise of low material consumption. The parts are light in weight and good in rigidity. After plastic deformation, the internal structure of the metal is improved, and the strength of the stamping parts is improved.

2. The dimensional accuracy of metal stamping parts is high, the size of the same mold is uniform, and the interchangeability is good. Meets general assembly and use requirements without further processing.

3. During the stamping process, since the surface of the material is not damaged, the surface quality is good, and the appearance is smooth and beautiful, which provides convenient conditions for surface coating, electroplating, phosphating and other surface treatments.

2. Control the quality problems of metal stamping parts

1. It is very important to test the first piece of metal stamping parts. In the first process before the mold is ready to be shipped, some stamping parts need to be trial-assembled, so that the relevant accessories can be trial-installed before production.

2. The hardware stamping parts are inspected according to the process time to prevent the variation in the stamping process, such as size problems when the production time is too long, and few holes caused by broken needles of the inserts.

3. Sampling inspection before the metal stamping parts flow into the next process to ensure the qualification of the material again.

The quality of metal stamping parts is very important for the quality of metal stamping parts, which is related to the use effect and longevity of stamping parts. The metal stamping parts mentioned above are the main products of Zhejiang Baifudu Electromechanical Co., Ltd., with many types, good die-casting effect and wide application range.

How to choose metal working fluid for automotive metal stamping parts?

1. Stamping equipment in the automotive industry

In addition to thick plate hydraulic press forming, stamping equipment generally uses mechanical presses. Centered on a modern high-speed multi-station mechanical press, equipped with uncoiling, leveling, finished product collection, transportation, mold library, and rapid mold changing devices, controlled by computer programs, it can form an automatic stamping production line with high production efficiency.

2. Introduction of metal stamping parts stamping products

Stamping has a wide range of applications. 60-70% of the world’s steel is sheet metal, most of which is made by stamping. Automobile body, chassis, fuel tank, radiator sheet, boiler drum, container shell, iron core and silicon steel sheet of motor and electrical appliances are all stamped.

The metal stamping process in the automotive industry includes mold manufacturing, sheet cutting, and subsequent processes including cleaning, rust prevention, and surface treatment. There are many types of oils involved, such as rail oil, cutting fluid, cutting oil, cleaning agent, anti-rust oil, high temperature grease, etc. The metal stamping parts processing manufacturer “Baifudu Electromechanical” recommends to you that the oil products used for metal stamping parts mainly include hydraulic oil (HM46, HM68), cutting fluid (SCC618A, SCC638), stamping oil (oily, volatile such as BT -17 Stamping and stretching oil. BT-17 stamping and stretching oil is based on refined mineral oil, compounded with various special additives such as extreme pressure, oiliness and rust prevention. It has good lubricity and extreme pressure resistance. Abrasion, rust resistance and oxidation stability, etc. It can effectively protect the mold and meet the stamping and drawing process requirements of stainless steel and carbon steel and other steel plates) and so on.

3. What is metalworking fluid

Metalworking fluids are mainly liquids for metalworking, which play the role of lubrication and cooling, as well as anti-rust cleaning and other functions.

It’s mainly for smack

Metalworking fluids can be roughly divided into 4 types: pure oil, soluble oil, synthetic fluid and semi-synthetic fluid:

1. The oil content of 90%~95% is pure oil metalworking fluid.

2. Emulsified metalworking fluids with a mineral oil content of more than 50%.

3. Mineral oil content of 5% to 50% is a semi-synthetic metal working fluid.

4. The one that does not contain mineral oil is a fully synthetic metal working fluid. The latter 3 are also commonly referred to as water-based metalworking fluids.

There are also many types of processing fluids

Metalworking fluids generally include cutting fluid, cutting oil, emulsion, stamping oil, quenching oil, quenching agent, high temperature oil, extreme pressure cutting fluid, grinding fluid, antirust oil, cleaning agent, blackening agent, deep drawing oil, thickener etc. Environmentally friendly synthetic fluids are the general direction of future development of metalworking fluids.

Well, the above is the relevant content of how to choose metal working fluid for automotive metal stamping parts, I hope it can be helpful to readers.

Common problems of car wiper motor

Common problems of car wiper motor

Q1. What is the RPM of the wiper motor?

A. The wiper motor speed is usually around 45 rpm (normal speed) and 65 rpm (on fast setting). It is also available in 6V, 12V and 24V configurations. A typical wiper motor uses 2 to 4 amps of current. Most wiper systems allow two speed settings for the wipers. In such a setup, the motor uses three brushes instead of two.

Q2. What is the function of the wiper motor pulse board module?

A. A module is a circuit board that contains the wiper system’s electronic control circuitry. It determines various actions, including speed setting, wiper parking, and closing and closing of the wiping mechanism. Simply put, it determines the operation of the wiper motor and linkage. Although the module is protected from the harsh conditions of the engine compartment, it can still be damaged. Fortunately, it’s a replaceable part.

Q3. Why do wiper motors need relays?

A. The relay uses less current to turn on more current for the motor. Some motors use relays, while others don’t. Typically, the wiper motor current rating determines whether a relay is required. Higher rated motors require one, while lower power types do not. If you have a rear windshield wiper, its motor probably uses a relay.

Q4. How long should the windshield wiper motor be used?

A. The wiper motor lasts as long as the life of the car. However, this doesn’t always happen. Depending on usage and operating conditions, components tend to fail earlier.

If you have to use your windshield wipers every day, chances are the motor will wear out after a few years. Electrical failures can also shorten lifespan if the wiper motor causes it to burn out. Poorly maintained wiper linkage can also stress the motor. To extend the life of your wiper motor, here are some helpful tips

Ensure regular maintenance, such as lubricating moving parts of connecting rods and replacing worn parts

Be sure to manually disengage wiper blades that have not been used for a while

Avoid situations where frozen wiper blades are used to prevent stress on the motor

Always make sure the wipers are in the correct parked position when not in use. They don’t stress the motor on startup

Get in the habit of turning off the wipers in front of the engine so they return to the parking space properly

Q5. What are the signs of a broken car wiper motor?

A. The wiper motor contains mechanical and electrical components. These can cause different symptoms when damaged or worn. With a keen eye, you can easily pick out these signs. Here’s how to tell if your windshield wiper motor is bad.

Wiper does not move when open

The wipers don’t stop when you want to

The wipers move slower than usual

You can’t change wiper settings, such as moving to a higher speed

Wiper motor rubbing or clanking

The wipers do not “stop” or return to the very bottom of the windshield when closing the wipers

Most signs are caused by a worn motor that needs to be replaced or damaged a single component that can be replaced. Blockage is also another reason why you may see bad wiper motor symptoms.

Q6. Is the wiper motor repairable?

A. They are, depending on the nature of the damage. Worn brushes can be replaced or the armature rewound. Other replaceable parts include gears in the motor drive. Cleaning a clogged wiper motor or its transmission components does not require replacement to restore its function. Many people don’t repair wiper motors. Instead, they replace the entire system.

Question 7. What is the price range of car wiper motors?

A. The wiper motor cost varies by manufacturer, ranging from $200 to $2000. Depending on the type of motor or model and the vehicle used, the number may be lower or higher. Different wiper motor suppliers will also have different price tags for the same product. When purchasing a replacement motor, we recommend that you compare prices from different suppliers.

Q8. What is the average cost of replacing a wiper motor?

A: You may pay between $100 and $500 for wiper motor replacement work. That doesn’t include the cost of purchasing components, which range from $200 to $2,000 for most models. If you choose to do it yourself, make sure you have the instructions for the program. Wiper motor replacement instructions are usually included in the product packaging.

Question 9. Can I replace the wiper motor myself?

A. The wiper motor position makes the task somewhat difficult. There are several components to remove, and you need to understand the process. You also need the right tools. If you have both the knowledge and the equipment to install, a DIY job can save you about $1,000. Having said that, it is always recommended to let a mechanic do the work.

Question 10. How do I buy a windshield wiper motor?

A. The wiper motor is made for a specific brand of car. So what you need to know about your vehicle type

What is the reason for the high scrap rate of metal stamping parts?

1. The raw materials do not meet the standard.

Raw material is the first guarantee for processing qualified stamping parts. If the raw material hardness and surface quality cannot meet the requirements, the scrap rate of stamping parts will be too high. Especially for some stamping parts with large deformation, if the raw materials are not qualified, cracks and damage will occur. Therefore, when purchasing raw materials, we cannot be greedy for cheap, but look for reliable and regular raw material business.

Second, the die is not installed as required.

The installation of the molding die does not meet the requirements of the specification, resulting in poor cooperation between the upper die and the lower die in the die, resulting in a high rejection rate. Stamping die is the basis of stamping parts processing. Installation is important if there is no problem with the mold. Don’t think that the installation of stamping die is very simple, even a small error may cause the production of stamping parts to be scrapped. The determination of the concentricity, clearance and flatness of the upper and lower dies has an important influence on the installation of the punching die.

Third, mold wear.

Long-term use of stamping dies, worn or loose parts can also cause product scrap. Many stamping plants do not carry out routine inspection and maintenance after installing production molds. Only in the case of relatively large burrs, the mold can be removed and the blade can be simply sharpened. We know that mold wear is not only the wear of the blades, but also causes the wear of some mold parts with use. After such parts are worn, it will affect the accuracy of the entire mold.

4. Illegal activities of workers.

When operating the press, the staff cannot follow the instructions, otherwise the paper will be fed incorrectly.

5. Wrong positioning device.

Due to the inaccuracy of the mold positioning device during the feeding process, it will cause improper coordination of each process, and even cause waste.

For metal stamping parts, since each stamping part requires different stamping parts, there must be specific reasons and specific analysis methods. If the scrap rate of stamping parts is too high, you might as well find out the reasons from these five aspects.

However, the precision requirements of metal punching and drawing parts in the processing industry are often very high, and the requirements for suppliers are also getting higher and higher. However, not all metal stamping factories meet the high precision requirements. Problems that should be paid attention to in the production of die castings:

1. Regularly check the punch, punch and punch mounting seat to ensure the same accuracy of the upper and lower turntables.

2. Metal stamping parts should be strictly cleaned before installation and use. On stamping parts, carefully check that the guide sleeve and die are well lubricated.

3. In order to ensure the drawing and pressing of the parts, the die spring should be replaced regularly to prevent the fatigue damage of the spring and affect the use of the drawing and pressing parts.

4. When installing the die, the stamper should use metal working tools to prevent damage to the stamping parts due to impact and extrusion during the installation process.

5. After the punch and punch edges of stamping parts are worn, they should be stopped and polished immediately. Conversely, edge wear will expand rapidly, die wear will accelerate, and stamping quality and die life will be shortened.

6. According to the installation steps of the die, install the punch and punch on a turntable to ensure that the punch is in the same direction. In particular, the hole punch should be installed strictly according to the orientation to prevent wrong installation and reverse installation.

6. How to calculate the scrap rate of stamping parts

1. The calculation method is as follows:

a. Calculated by weight Casting scrap rate = (casting scrap output / total casting output) X100%

b. Calculated by quantity Casting scrap rate = (number of scrap castings / total number of castings) X100%

2. Scrap Rate, Scrap Factor

The probability that a component will become defective while it is being used to make the parent. The same component may have different scrap rates when used to produce different parent items, so the scrap rate is defined in the bill of materials. When MRP uses the BOM to expand the POR (planned order issuance) of a material to calculate the GR of its components, it will be divided by (1-scrap rate) to expand the GR (total demand) of the components.

The above is the relevant content of the high scrap rate of metal stamping parts and the scrap rate of stamping parts. Qualified products should be strictly regulated. Only by ensuring product quality, stamping parts manufacturers can stabilize the source of customers and go further. Hope the above content is helpful to readers.

How Exhaust Gas Temperature Sensors (EGT) Monitor Exhaust Emissions

Exhaust gas temperature sensors can be found on a variety of vehicles:

• Medium and heavy duty trucks and trucks

• bus

• Construction machinery

• SUV

• Mining machinery

• Agricultural machinery

• Special vehicles (fire trucks, sprinklers)

Design points of drawing die

1. Material selection

In general, the raw materials of the stretched products are specified by the customer, but the same raw materials also have different models, such as cold-rolled sheets: 08Al.08.08F.10.15.20 steel, if the selection is improper, it may not be produced. Qualified product.

Second, open the blank

Generally speaking, most of the convoluted stretched products with simple rules and forms are stretched without thinning, which can be directly determined according to the principle of the product of the front and back sides of the stretch. Assuming that the shape of the tensile member is complex, and occasional tight flow may occur and become thinner, the size of the opening cannot be accurately calculated in general, and the three-dimensional opening is estimated, which is the so-called sample.

3. Tensile calculation coefficient

The tensile coefficient is very important. It needs to be stretched in several steps to ensure that there are no cracks, wrinkles and other problems that require the use of the tensile coefficient formula. This is one of the main parameters in the drawing process calculation and is often used to determine the drawing sequence and number of draws.

However, the tensile coefficient is not fixed, and there are many influences on the tensile coefficient, including: raw material type, thickness, and tensile structure type. The number of stretching, the stretching speed, the large arc of the stretching insert, etc. However, the average person can still consult the table to calculate.

Fourth, it is the problem of ordinary tensile test

During the drawing process, there are often phenomena such as drawing and wrinkling. If there is cracking, it is necessary to study the flow of raw materials. You may wish to apply lubricating oil on the die, not on the punch. Maybe when there is a 0.013-0.018mm film on the product side of the die, it is usually used. The fitter wraps the film.

There are more wrinkles and less cracks, which infers the flow state of the raw materials. Adjustment procedure: adjust the blank holder pressure, increase the drawing rib, change the arc radius of the upper and lower die inserts is too large, the workpiece mouth, etc. Generally speaking, drawing parts are molds with high technological content, whether it is design, processing, assembly or debugging…

Secondly, the design of the tensile parts should be conducive to the improvement of the utilization rate of metal materials, reduce the variety and specifications of materials, and reduce the consumption of materials as much as possible. Allows the use of inexpensive materials to make parts as scrap-free and as low-waste as possible. When designing the extension piece, when it is determined that it can be used normally, the requirements for dimensional accuracy grade and surface roughness should be reduced as much as possible, which is conducive to the interchangeability of products, reduces waste, and ensures stable product quality.

The tensile design requires simple shape and reasonable structure, which is conducive to simplifying the mold structure and simplifying the number of processes, that is, using fewer and simple drawing processes to complete the processing of all parts; less processing by other methods is also conducive to wire drawing operations. It is convenient for organizations to realize mechanized and automated production and improve labor productivity. Tensile parts are designed to meet the usage and technical performance of the product, and are easy to assemble and repair.

The above content is the design of the drawing die. For the general drawing process, simple dies, low melting point alloy dies, die sets, wire drawing manufacturing systems, etc. can be used to organize the drawing processing of multi-variety and small batch parts. Hope the above content is helpful to readers.