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TECHNICAL GUIDE

PUNCHING TOOLS

Vol.6 FOR CLEARANCE OF THE CUTTING DIE

TECHNICAL GUIDE

PUNCHING TOOLS

Vol.6 FOR CLEARANCE OF THE CUTTING DIE

Selection of the die clearance also has a significant impact on the quality of the workpiece and the tool life.
This time, we summarized the selection criteria of the clearance. Also we will introduce "one pitch thread form" as a forming tool.

WHAT IS CLEARANCE ?

Clearance refers to difference in dimension
between punch dimension and die dimension.

WHAT IS CLEARANCE ?
Clearance = B - A

REFERENCE APPROPRIATE CLEARANCE

Clearance = material thickness　x　clearance ratio
Material Clearance Ratio Tensile Strength
(N/㎟）
Servo / Hydraulic Machine Mechanical Machine
Mild Steel
(Cold Roll)		 0.2～0.25 0.15 More than
270～
Mild Steel
(Hot Roll)
Stainles
(Hard)		 0.2～0.3 0.2 More than
520～
Stainless
(Soft)		 More than
450～
Aluminum
(Hard)		 0.15～0.25 0.1 More than
215～
Alminium(Soft) More than
95～
Copper 0.2～0.25 0.15 More than
275～
Brass 0.2～0.3 0.2 More than
410～
High Tensile Steel More than
590～
  • 1.The shear resistance should be about 80% of the tensile strength as a guide.
  • 2.Please multiply x 1.4 to the calculation result in case of more than 3.2mm thickness.
  • 3.Please calculate based on the number of shear resistance and Tensile strength for the material which is unspecified on the left table.
  • 4.If there is a workpiece, please actually perform punching and purchase the appropriate clearance referring to the table below.
  • 5.The minimum clearance is depends on machine specifications. Please also check the machine specifications.

THE INFLUENCE BETWEEN CLEARANCE AND MATERIAL(PRODUCT)

Clearance Wide Proper Narrow
Conditio of slug
Wide
Proper
Narrow
Roll over MORE NORMAL LESS
Shear plane LESS NORMAL MORE
Fracture surface MORE NORMAL LESS
Burrs MORE LITTLE LITTLE
Warp MORE LITTLE LITTLE
Accuracy in
dimension		 WORSE BETTER BETTER
Comment Negative influence of slug pulling Increase tonnage

〔 Condition of slug 〕

Condition of slug

ONE PITCH THREAD FORM

UNNECESSARY TAPPING PROCESS！

We recommend one pitch thread form for screwing in places where relatively strong strength is not required, such as decorative panels and covers.

One pitch thread form is…

  • ・Process that uses a turret punch press to form one pitch of screws on a material.
  • ・After pre-hole (Round punching) processing, it can be easily processed by forming. Also it can be processed at high speed compared to tapping.
  • ・High speed punching press compared to tapping process.
  • ・If the screw size is the same, it can be formed with the same tool even if the plate thickness is different.
    (Adjustment of the punch length is necessary.)

〔 Example of use 〕

Example of use

TOOLING STRUCTURE (NC 1-1/4)

Process Procedure
Pre-hole
→
↓
Forming
Applicability

Thickness of material :
0.6mm ～ 1.6mm
Thread Size : M3 ～ M8

  • ※Please consult the tool sales desk
    for Non-Standard dimension.
Recommended tool size
Thick Turret Type 1-1/4 (B) station
MURATA 114 type C or D station

〔 FORMING DOWN 〕

FORMING DOWN

〔 FORMING UP 〕

FORMING UP

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Vol.6 FOR CLEARANCE OF THE CUTTING DIE(746KB)

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