Common breakdowns and solutions for automobile stamping molds

Nov 04, 2020

The following breakdowns often occur in the automobile stamping mold process, which will cause inconvenience to production. Solutions for the breakdowns will be explained as follows:

Deformation of flanging plastic parts
In the process of flanging and shaping, the deformation of the part often occurs. Generally, the quality of the part will not be greatly affected for the non-surface parts. However, as long as there is a little deformation, the quality defects will be great for the appearance, which will affect quality of the whole batch.

Reasons for deformation of flanging parts

The sheet material will deform and move in the forming and flanging process. Deformation will occur if the pressure-plate-force is not tightly pressed.
In the case of large pressure-plate-force, the uneven pressing surface will result in partial gaps and the above situation will also occur.

Solutions

Increase the pressure-plate-force, if it is a spring pressure-plate-force.
If partial deformation still exists after increasing the pressure, red lead can be used to find out the specific problem and check whether the pressure-plate-force is partially dented. At this time, the method of welding and pressing the pressure-plate-force can be used.
The pressure-plate-force should be matched with the lower surface of the mold after it is welded.

Moulding Knife Breakage
Knife breakage caused by various reasons during the use of the mold will have a certain impact on the quality of the part, which is one of the most common things in mold repair. The repair steps for the knife breakage are as follows:

If the breakage is very small, usually the breakage should be ground with a grinding machine to ensure that the welding is firm and the knife won’t easily break again.
Use the corresponding welding rode for welding. Currently, we use D332 welding rode for build up welding on the cutting edge. Before building up welding, the reference surface including clearance surface and non-clearance surface should be selected.
Smooth the non-clearance surface of the cutting edge according to the benchmark left in advance.
Draw lines based on the transition piece. If there is no transition piece, you can use the benchmark left in advance to rough grind the clearance surface.
The clearance surface can be repaired on the machine platform, and the auxiliary grinding can be done with the help of clay. Be careful in the process of repairing. Start the press machine as slowly as possible, and use the height of the mold to adjust downwards if necessary, avoiding the knife edge being bad.
The knife edge gap should be reasonable. For the steel plate stamping die, the unilateral knife edge gap should be 1/20 thickness of the sheet. However, in the actual operation process, the size of the gap can be checked by stamping of sheet materials, as long as the burr of the part meets the requirements after cutting. In general, the criterion for the size of the burr is that the height of the burr should not be greater than 1/10 of material thickness of the sheet material.
Check whether the clearance surface of the knife edge is consistent with the cutting direction.
After the clearance is set, use oilstone to make the clearance surface of the knife edge smoothly, reducing the friction between the sheet material and the knife edge and resistance of waste falling during production.