What is die wear?
Die wear, simply put, is a change in a die
surface that may affect die performance.
Why should I worry about
die wear?
Die wear, like death and taxes, is
unavoidable. But can be controlled so that your dies live long and
productive lives.
What can I do about die
wear?
Some types of wear occur gradually and by
monitoring die wear, die maintenance and replacement can be predicted.
Other types of die wear occur rapidly and are unpredictable. These
types of wear can put a process out of control or cause die breakage.
The best defense against wear is to know the types of wear and how to
deal with each.
There are
several types of wear including:
Adhesive
Wear
Caused by: Cold welding
Results in: Pickup, scoring, etc.
Abrasive
Wear
Caused by: Hard surfaces or particles
Results in: Metal removal
Fatigue
Wear
Caused by: Repeat loading
Results in: Micro-cracking, spalling
Chemical
Wear
Caused by: Chemical Reaction
Results in: Reaction Products
Mixed Wear
Caused by: Combinations of above
Results in: scoring, scuffing, galling
Adhesive wear is actually a build up of
workpiece material on the die known as pickup. These photographs show
pickup on a tube bending mandrel and the resulting scoring on the
inside of the bent tube. The scoring increased drag and caused the
tube to split during the bending process.
Selecting the proper die material/coating
and choosing a lubricant that provides protection against
metal-to-metal contact can avoid this type of wear.
