Handling of common problems in stamping parts processing and application

 Handling of common problems in stamping parts processing and application

  • 1. Adhesion, scratches: defects on the surface of the part or mold due to the friction between the material and the convex mold or the concave mold;
  • 2. Burr: It mainly occurs in the cutting die and blanking die, and the gap between the cutting edges may be large or small, which will produce burrs;
  • 3. Line offset: When the part is formed, the part that first contacts the mold is squeezed to form a line;
  • 4. Concave and convex: foreign matter (iron filings, rubber, dust) mixed in the uncoiling line causes convex and concave;
  • 5. Circuiting: due to uneven stress, poor matching of drawbeads or poor control of the press slider, the r-corner part or embossing part of the workpiece is formed to be circuitous and strain;
  • 6. Wrinkles: due to poor adjustment of the press slider, low press accuracy, improper adjustment of air cushion pressure, large punch or r part, etc., wrinkles on the edge or r part are caused.
  • 7. Other detailed questions: In daily consumption, you will encounter situations where the punching size is too large or too small (may exceed the specification requirements) and the size of the punch is quite different, except for the design dimensions of the convex and concave molds.

In addition to factors such as machining accuracy and blanking clearance, the following aspects should also be considered to deal with it.

  • ⑴. When the punching edge is worn, the tensile stress on the material increases, and the tendency of stamping parts to turn over and twist increases. When turning over, the size of the punching hole will become smaller.
  • ⑵. The strong pressure on the data causes plastic deformation of the data, which will cause the punching size to become larger. When the strong pressure is reduced, the punching size will become smaller.
  • ⑶. The shape of the edge of the punch’s edge. If the end is trimmed with a bevel or arc, the punching part is not easy to turn over and twist due to the slowing of the punching force, so the punching size will become larger. When the end of the punch is flat (no bevel or arc), the punching size will be relatively small.

Touch inspection

Wipe clean the surface of the outer cover with clean gauze. The inspector needs to wear touch gloves to touch the surface of the stamping part along the longitudinal direction of the stamping part. This inspection method depends on the experience of the inspector. If necessary, oilstone can be used to polish the detected suspicious area and verify it, but a this method can be regarded as an effective quick inspection method.

Whetstone polishing

  • 1. First wipe the outer surface of the outer cover with clean gauze, and then polish it with oil stone (20×20×100mm or larger), and polish the arc center and the hard-to-reach center with a relatively small oil stone ( For example: 8×100mm semi-circular whetstone)
  • 2. The choice of whetstone particle size depends on the appearance (such as roughness, galvanizing, etc.). It is recommended to use fine-grained oilstone. The direction of whetstone grinding basically stops along the longitudinal direction, and it fits well with the appearance of the stamping parts, and the local special center can also supplement the horizontal grinding.

Flexible gauze polishing

Wipe clean the surface of the outer cover with clean gauze. Use a flexible sand net to closely adhere to the surface of the stamping part and polish it to the entire surface in the longitudinal direction. Any pitting or indentation will be easily found.

Oil inspection

Wipe clean the surface of the outer cover with clean gauze. Then use a clean brush to apply oil evenly to the entire surface of the stamping in the same direction. Put the oiled stamping parts under strong light for inspection. It is recommended that the stamping parts be erected on the car body. This method can easily find tiny pits, pits, and ripples on the stamping parts.

Visual inspection

Visual inspection is mainly used to find abnormal appearance and macro defects of stamping parts.

Inspection fixture

Put the stamping parts into the inspection tool, and stop testing the stamping parts according to the operation request of the inspection tool statement.

Safe consumption

In practical consumption, process experiments similar to the stamping process are commonly used, such as drawing performance test, bulging performance test and other test data stamping performance to ensure waste quality and high pass rate.

The accuracy and structure of the mold directly affect the forming and accuracy of the stamping parts. Mold manufacturing cost and life are important factors that affect the cost and quality of stamping parts. Die design and manufacturing require more time, which prolongs the production preparation time of new stamping parts.

Standardization of mold bases, mold bases, and guides, and the development of simple molds (for small batch consumption), compound molds, multi-station progressive molds (for mass consumption), and the development of rapid mold change and installation can reduce the preparation work for stamping consumption And shortening the preparation time can make it suitable for reducing the amount of preparation for stamping consumption and shortening the preparation time, so that the advanced stamping technology suitable for mass consumption can be reasonably applied to small batches of various types of consumption.

Except for the hydraulic press for forming thick plates, the stamping equipment generally uses mechanical presses. Transportation and other machinery, mold library and quick mold change installation, and application of computer program control, can form an automatic stamping production line with high consumption rate.

Under the condition of consuming dozens or hundreds of stamping parts per minute, the processes of feeding, stamping, outputting, and discharging waste are completed in a short period of time, often causing personal, equipment and quality accidents. Therefore, safe consumption in stamping is a very important issue.

In the stamping process of ordinary workpieces, because the temperature will rise quickly during the stamping process, especially in the cold forging stamping process, it is necessary to smooth the product. If it is not smooth, it is directly stamped, welded-assembled, and there is no oil on the surface. The parts are easy to weld and assemble. The research and theories show that Amicable Metal Inert Gas Arc Welding, Tungsten Gas Maintenance Arc Welding, and Resistance Welding have excellent results.

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Author: ANDY Minghe