ANGLE DEFECT

The angle defect is mainly affected by the machine and the material.
This time, let's divide the causes into “tool”, “machine”, and “material” and consider the countermeasures.

IF TOOL IS THE CAUSE

1. USE WORN AND DETERIORATED TOOLS

Perform regular re-sharpening of the cutting edge and inspection of the tool.

2. A TOOL THAT SHOULD NOT BE USED WAS USED

(e.g.) Gooseneck punch was used instead of standard punch.

Bending with a standard punch, compared to a gooseneck punch, has less deflection and better accuracy as the “C shape” of the tool relief is smaller.

Choosing the best tool for the bend is of the utmost importance.

IF THE MACHINE TABLE IS THE CAUSE

• ■Machine level is not right
• ■There is an error between the table rise and the punch lower position.
• ■There is a scratch on the tool mounting surface (the surface where pressure resistance is applied) on the machine side.

If you notice any of these incidents, contact the machine manufacturer for repair or maintenance.

IN CASE OF INTERMADIATE PLATE

• 1.If it is deformed, scratched or damaged, repair or replace it.
  Repair may be required if the pressing surface that the tool contacts is rough by touching it with your finger.
• 2.If any bolts are loose or forgotten, tighten them.
• 3.If it is not mounted under pressure, it is mounted again.

Let's check periodically!

POINT

WHEN THE WORK MATERIAL IS THE CAUSE

• 1.Difference between nominal thickness and actual thickness.
• 2.Variation of sheet thickness for each lot.
• 3.Variations within a regular size sheet.
• 4.Differences in material properties between different manufacturers. (Hardness, etc.)
• 5.Materials with large errors that are seen in imported materials due to cost reductions.

When high-precision bending is required, the use of “high-precision material thickness” can reduce the variation compared to standard materials. Generally, the variation is about half of the standard material.

• ■Since the variation is extremely small, the total time of the bending operation is reduced.
• ■The accuracy is particularly stable with the obtuse bent product, and the defect rate is reduced.
  These lead to improve sheet metal processing quality.

Although it has the disadvantage of increasing the cost of procurement,
it is also important to compareit with being busy with the work to deal with defects.