tool die design metal stamping


Tool & Die Making
Bend Radius
Deep Drawn
Fine Blanking
Progression strip layout

Slug pulling prevention
Tool die Design
Tool die design book

Jig and Fixture
Jigs and Fixture Design

Materials treatment
Annealing metal
Case hardening
Electrical Conductivity
heat treatment process
heat treating steel

Thermal Expansion

Alu comparison table
Aluminum Tempering
Carbon Steel
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Stainless Steel

Stainless Steel comparison table
Tool Steel equivalent
Tungsten Carbide
Wrought stainless Steel

Conversion Charts
Drill Angle
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Technical articles
Work Done

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Tolerance chart ISO
Surface Roughness
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Quality Control
Process Capability CPK
Sampling plan
Level I, II, III

Engineering Plastic
Machining of plastic
Selection of plastic

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,