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Fundamental Tool & Die Making techniques

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Bend Radius
Deep Drawn
Fine Blanking
Progression strip layout

Slug pulling prevention
Tool die Design
Cutting clearance

Downloadable Ebooks

Tool die design booknd Fixture
Strip layout

Jigs and Fixture Design Book

Geometric Tolerances

ISO tolerance for shafts
ISO tolerance for holes
Surface Roughness
Surface Texture

Quality Control Co

Process Capability CPK
Sampling plan
AQL Level I, II, III


Slug pulling prevention

Slug pulling during stamping process = slugs can easily pull up for one or more of the following reasons:

The die cutting edges have become worn to a bell-mouth.
The material being cut is very thin and light in weight.
The die is running with excessive lubrication and has just been sharpened.
The cutting clearance is too big or has worn off.
The slugs are not held on all sides.

Many methods can be applied to keep slugs down.
ejectorAdding ejector into the punch, if space is permitted. ( Fig. 1 ) This method is most effective and most common method in the market.

slug pullingIf the cutting punch is unable to put in any ejector due to the space constrain. A small shear angle ( slug killer ) can be ground on the punch face as shown in Fig. 2. Slug can be held in the die profile when slug spring back to it original shape while punch retract.

Another effective method is to machine a small groove ( 0.005 - 0.01 mm ) to the die profile to creates a precise amount of interference. The grooves were machined at an angle ( 3 - 5 deg. ) to the die surface. ( See picture below ) The slug expands into a series of this special grooves, pressure between the slug and the die land occurs, preventing it from pulling back through the top of the die and onto the work zone. The slug is then safely cleared on the next stroke from the punching zone

. slug retention

Slug pulling is a problem that can be prevented by proper design and correct techniques,




Materials & Tretment

Annealing metal
Case hardening
Material density
Electrical Conductivity
heat treating steel


Equivalent and standards

Comparision table

Alu comparison table
Carbide equivalent chart
Carbon Steel
Copper alloy
Low alloys
Nickel alloys
Stainless Steel
Steel comparison table
Tool Steel equivalent
Tungsten Carbide
Wrought stainless Steel
Inch - metri Conversion Charts
Periodic Table of elements


Drill Angle
Drill size


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