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TECHNICAL GUIDE

PUNCHING TOOLS

Vol.1 COUNTERMEASURES FOR SLUG PULLING IN PUNCHING PROCESS

TECHNICAL GUIDE

PUNCHING TOOLS

Vol.1 COUNTERMEASURES FOR SLUG PULLING IN PUNCHING PROCESS

One of the problems that occur when punching with an NC turret punch press is slug pulling.
It is generally said that slug pulling are round or simple in shape and often occur when the thick plate is thin.
This chapter summarized some measures, including slug catcher die, for this slug pulling.

Mechanism of slug pulling

  • A.Vacuum adsorption
  • B.Oil film adsorption
  • C.Magnetic adsorption
  • D.Cutting edge pressure bonding by burrs etc.
Mechanism of slug pulling

Countermeasures for slug pulling

Slug Catcher Die（Standard specification）

Catch the slug to prevent slug pulling.

① Material is cut off at [A] part.

① Material is cut off at [A] part.

② The slug is compressed in the process of punching at [B] part.

② The slug is compressed
in the process of
punching at [B] part.

③ Drags the slug through the relief.

③ Drags the slug through the relief.

④ [B] part is narrower than [C] part so the slug cannot comes up.

④ [B] part is narrower
than [C] part so the
slug cannot comes up.

COUNTERMEASURE FOR UPPER DIE (PUNCH SIDE)

１) ADUST I NG UPPER TOOL I NG HEIGHT

Insert punch edge deeply to inside the die to push the slug properly.

Insert punch edge deeply to inside the die to push the slug properly.
２) SLUG EJECTOR（STANDARD SPECIFICATION）

The slug ejector attached to the cutting edge of the punch forcibly removes scraps.
(Preventing adhesion/ adsorption)

Attach the slug ejector to punch edge and it push the slug forcibly.
３) COMPRESSED AIR

The compressed air is discharged directly from the air hole of the tool center and blown to the slug to forcibly remove the slug.

Drop the slug forcibly using compressed air directly from the center air hole.
４) SHEAR ANGLE

By attaching a shear angle to the cutting edge of the punch, the slug is deformed and its repulsive force (spring-back) is used to prevent slug pulling.

Put shear angle on punch edge.The slug would be contorted and utilize repulsion of slug deformation.

COUNTERMEASURE FOR LOWER DIE（DIE SIDE）

１) SELECTION OF DIE CUTTING EDGE

The cutting edge has the following specifications in addition to the slug catcher.

There are the following specifications to the cutting edge in addition to slug catcher.
２) DEPOSITION PROCESS（D Process）

Put electrical super hard spot(Carbide coating) onto inside of die hole.

Put electrical super hard spot(Carbide coating) onto inside of die hole. Other Solution

Other Solution

  • 1.Do not use the processing oil.
  • 2.Use with an appropriate clearance.
  • 3.Do enough demagnetizing.

We recommend that you try these methods individually or in combination,
depending on the material, thickness and punched form of the workpiece.

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