How To Handle With The Ten Common Malfunctions For Stamping Die?(2)

Material Camber

Reasons summarized as blow:
1.Stamping burr (especially for the carrier);
2.Material burr, tooling without trimming;
3.Improper punch depth (too deep or too shallow);
4.Part crushed, there are scrpes in the die;
5.Swaging too deep partially or local damage at swaging area;
6.Tooling design;

The relative countermeasures as blow:

1. Grinding blanking die.
2. Change material, tooling equipped with trimming.
3. Re-adjust punch depth.
4. Clean the die, solve jumping scraps and crushing problem.
5. Make sure eash unload and die inserts are with right height, otherwise need to modify the damage area.
6. Use bending organization adjustment.

Core Plate Broken & Tipping

Reasons show as blow:

1. Caused by scraping, waste material Jamming,tooling stucking…..
2. Improper feeding, cut hald material;
3. Punch is too weak;
4. The sie of the punch apart is too close, small punch broken caused by material tracking when blanking;
5. Some sharp conners on the punch and die;
6. Blanking clearance is a little small;
7. No stamping oil or the oil with strong volatilenness;
8. Unevenness & offset blanking clearance,punch and die intervened;
9. Unload insert weared or with bad precision,there is no precision guiding function;
10. Tooling weared with bad guiding function;
11. Punch and die used wrong material, hardness do not match;
12. Guide pin weared;
13. Shim added improperly;

The relative countermeasures as blow:

1. Solver scraping, waste material Jamming, tooling stucking problem.
2. Pay attention on feeding stage,cut the stipper and clean the die in time.
3. Change the design, add whole strength of the die, reduce die blade size, modify the punch blade with a slope or arc, cut the small part.
4. Reduce small punch’s height about one material thickness when compared with big punch.
5. Change the design.
6. Control fabrication precision for the punch and die or change the desiging clearance, added the small part’s blanking clearance properly.
7. Adjust the adding speed of the stamping oil or change oil directly.
8. Check each forming insert’s precision, change or replace the bad ones, control fabrication precision;
9. Grinding or replace.
10. Replace guide pillar and guide sloove, pay attention on daily maintainence.
11. Change material, use proper hardness.
12. Replace guide elements.
13. Modify, reduse shim quantity if possible, use steel cushion, the shim under the die should be added under the cusion block.

Bending deformation & dimension problem

Reasons as blow:

1. Guide pin weared, pin diameter isn’t enough;
2. Bend guiding part weared, precision isn’t good;
3. Bending punch and die weared (damaged due to the presure);
4. Tooling’s yield isn’t enough;
5. Material slipped, there is no guiding function for bending die and punch,no pre-press at bending stage;
6. Tooling with improper structure and desiging zise;
7. Improper bending caused by part burr;
8. Too much shims added for punch and die at bending stage, this made dimension unstable;
9. Material thickness variated;
10. Materials mechanical shape variated;

The relative countermeasures as blow:

1. Change guide pin.
2. Re-grind or just replace it directly.
3. Check and repair.
4. Revise the design, add guiding and pre-press function.
5. Change designing dimension, explode banding stage, like add bending shaping.
6. Grinding blanking die.
7. Adjust and adopt whole steel cushion.
8. Change material,control feedstock quality.

Part with High-low Pin(muti-cavity)

Reasons as blow:
1.part with burr;
2.Part crushed, there are scraps in the die;
3.Bending punch and die demaged;
4.Material turning over when blanking;
5.Related swaging area weared,crushed;
6.Related tearing area with imconformity tearing size,die weared;
7.Related easy-broken area with imconformity pre-bending depth,punch and die weared or tipped;
8.Related convex area weared or tipped seriously;
9.Tooling design defect;

The relative countermeasures as blow:

1. Grinding blanking die.
2. Clean tool, solve scraps floating problem.
3. Re-grinding or changing the insert.
4. Grinding blanking die, adjust or add forced function.
5. Check, maintain or replace directly.
6. Grinding or replacing, make sure all the tearing situation are the same.
7. Revised the design, add high-low adjustment or add shapping stage.

Improper maintainence

Reasons:

1. Tooling without fool-proof function, wrong direction, malposition (different stage) are caused by assembly negligence;
2. The insert didn’t in original state when clearance skewed;

The relative countermeasures as blow:

1. Modify the die,add fool-proof function.
2. Marked on the tooling, once assembly finished, need to check and confirm (compared with the stripper),and record it in paper,in order to tracing it.

During stamping production, it is very important to do tooling daily maintainence, means daily check press machine and stamping die are in normal situation, like add stamping oil for the supply guidance department, tooling checking before set-up; blade checking; locking confirmation for each part….. Only in this way, we can avoide many sudden accident. You must think first then do it when maintain the tool, and also record the maintain experience.