In the manufacturing process of automobile stamping die, it is often encountered that the upper die absorbs material, which leads to double-punching. If the double-punching is light, the parts will be damaged, and if it is heavy, the die will be damaged, and even people will be killed or injured. It must be strictly prohibited to double-punch because of the upper die absorbing material. The picture below shows that the mold base of a project is directly cracked because the upper mold absorbs material, which causes the operator to double-feed. Let’s talk about how to solve the problem and how to prevent it in the later stage with this case analysis.
Field description: This set of die is a flanging shaping die. Because the upper die clamped the parts on the upper die after flanging, the operator did not find another part, and the die went down to the bottom dead center again, causing the die seat of the lower die to crack.
On-site mold is broken by double material
Cause analysis and on-site rectification measures: Cause analysis: The main reason for the material absorption of the upper die is that the ejector installed in the upper die is not strong enough to eject the parts smoothly. Temporary measures: As this part is ordered every month, we must hurry to restore and produce qualified parts. Engineers will reinforce the cracked mold (adding floor and side bolts) according to previous project experience, and permanent measures: re-casting and manufacturing.
Temporary measures: reinforce the mold
Combined with past cases, the causes of upper die suction are summarized:
1 Vacuum suction caused by insufficient exhaust of the upper die
2 Parts are stuck on the upper die after springback.
3. Parts are stuck in the upper die due to galling.
4. The calculation of the unloading force of the upper die plate is too small, which leads to the upper die sticking (often occurring in the trimming process).
Combined with past cases, this paper summarizes how to solve the problem of preventing the upper die from absorbing material;
1 Make sure that the discharging force is calculated correctly in the preliminary design stage (remember not to choose the lower elastic component in order to save costs).
2 The vent holes must be made in the early manufacturing to ensure that the gas can be discharged smoothly (care must be taken not to cause appearance defects when making the vent holes of the outer cover).
3 Make the ejector pin for the non-appearance area of the inner panel or the outer cover to ensure that the parts can be ejected (the ejector pin should not be set on the inclined plane or in the place where the feeding is rapid to prevent the mold from being damaged due to the fracture of the ejector pin).
4. Parts must be brushed properly in mold production.
5. Try to choose the ejector pin with the function of delaying the lifting in the installation machine (generally, the press that automatically produces four doors and two covers needs the ejector pin delay function).
6. For continuous dies that require high punching times or may be loaded with materials, such as upturned holes and flanging, a bridge-collapsed strip stabilizer can be set.