1. Strip design and CAE analysis
The design of the strip should be combined with CAE analysis to control the material thinning rate below 25%.
For deep-drawn stainless steel materials, high-frequency annealing can be performed after pre-stretching to make the thinning rate acceptable up to 40%.
When designing the material strip, you should fully communicate with the customer and obtain the original mold photos or structure drawings as reference.
Properly leave an empty step (when the length of the mold permits), which helps to adjust the mold change after the trial mold.
2. Lifting design
The material lifting design of the continuous mold must ensure that the lifting bar can lift the whole material belt, or else automated production cannot be realized.
3. Mold material and surface treatment
material selection, heat treatment and surface treatment (e.g. TD, TICN) directly affect the mold life and product quality.
Especially for tensile parts, the surface of the mold without TD treatment is easy to pull burn hair, TD treatment time is generally 3-4 days.
4. Adjustable insert design
For holes or molding surfaces with strict tolerance requirements, it is recommended to use adjustable inserts to facilitate adjustment and improve accuracy.
The upper and lower molds are designed with adjustable inserts at the same time, so that they can be fine-tuned in the trial mold and production process.
text mark (word mark) should be removable on the punch press to avoid the waste of time caused by dismantling the mold.
5. Nitrogen spring design
Determine the nitrogen spring pressure according to CAE analysis to avoid designing too large, resulting in product rupture.
Too small pressure will lead to product wrinkles, which can be improved by locally increasing the stretching rib.
6. Red Dan fit and fit rate control
Red Dan test must reach more than 80% fit rate, before cutting processing and CMM testing.
If the datum hole and datum surface have been well coordinated and the product is stable, the fit rate can be reduced appropriately.
7. 3D complex product processing
When 3D laser processing is used, accurate 3D graphics must be made first and CNC datum points must be made before laser processing.
3D laser need to use positioning sand pattern to ensure the accuracy.
8. Trial mold and friction optimization
The trial mold can place sandpaper at different positions to test the stretching effect and determine the optimal friction resistance.
When mass production, you can use movable stretching rib or twisted dot array (grinding twisted plated parts) at the corresponding position to optimize the alignment.
9. Molding angle adjustment
Adjust the molding angle by reducing the bending R angle or moving the bending reference to ensure the final angle meets the requirement.
10. Stainless steel mold surface treatment
Stainless steel molding dies should not be treated with TD, but should be treated with TICN (PVD) to improve wear resistance.
11. Waste discharge optimization
The inclination of the waste funnel shall not be less than 30° to ensure smooth waste discharge.
For low angle waste boxes, Pneumatic Vibration (PV) can be installed to improve waste discharge.
12. Shear line optimization
Shear edge lines affected after molding should be cut after molding to ensure shear accuracy.
Cross-cutting can be used to optimize the shearing effect in special positions.
13. Punch molding accuracy control
For multiple datum holes, it is recommended to punch and mold the holes at one time, to avoid step-by-step punching and cutting resulting in decreased positioning accuracy.
14. Cracking problem solution
Reduce product rupture by adding wrapping, squeezing, enlarging sheet rod molding area or pre-punching holes during pre-stretching.
CAE analysis should be done before any mold change to find out the best solution.
15. Mold machining reference control
When wire EDM processing, the pin holes are used as touch counting reference to ensure the processing accuracy.
After ·CNC programming, the operator needs to provide two datum hole coordinates, and the programmer will calculate the angle and adjust the program angle for machining.
When the template is processed for the first time, it is processed by touching the edge without calculating the angle.