The production of punches, forming tools as well as dies and other tools is typically described as a method that uses brutal force. This allows for the piece to be cut, pierced and shaped, or in different form. These are often referred to as "chipless" techniques for machining. Today's buyers of tool/die and machinists must be more aware of the properties of the bare steel that makes up the blank. They must be aware of the interplay with the entire process: design of the tooling and making raw materials for the tool, processing and heat treating, coating properties, materials that can be machinable and cycles, cycle times required, allowed machine downtime, the process of heating and processing for tooling.
Coating Benefits for Punches and Dies
Based on the application you are using, ACS can offer a variety of PVD coatings that add value and reduce costs for punches, dies, as well as forming tools. First, the combination of the high hardness of the film and the low coefficient of friction impart the desirable properties of:
less friction in sliding
greater wear resistance to abrasive wear
reduced punch & die retraction forces
improved surface hardness and toughness
Tablet punches are increasing tablet releases
lower galling, reduced wear on adhesive and material wear
no reaction to the material due to a level of chemical inertness
All these enhancements have to be achieved while preserving the crucial dimensions and tolerances that punches, dies and forming tools demand when in use. This is why there is a value of using PVD is the means of providing the useful surfaces.
EXTEND LIFESPAN OF PUNCHES and DIES as well as FORMING TOOLS
When coated with PVD thin-film coatings dies, punches, and tool forming equipment will last for a longer life span. The Platit Arc-Deposition Systems can be operated at temperatures ranging from 160oC to 490oC. These temperatures are well suited for a wide range of water, oil, or air hardening steels, such as S1, S7 A2 and D3, as well as W2, O1 & O2, M1 & M2, T1, M4420SS, different alloys, and powdered metals that are used for the manufacture of punch die set and other tools for forming, and metals like tungsten carbide.
PVD VS CVD COATING
PVD is preferable over CVD for coating dies, punches and tool for forming. This is due to the fact that PVD uses lower temperatures during the process to ensure the hardness that is treated with heat and the austenitizing temperature of the forming tool's substrate materials.
TIGHTER TOLERANCE
Because PVD provides coating thicknesses that range from 1 to 5 um range (0.00004" to 0.00020") The components can be machined to final size prior to coating, permitting the resulting clearances required in close tolerance die and punch applications.
Increased wear resistance
The expression "wear" can be used to refer to the impact of corrosion or abrasion on contact with other substances or tools, grit or tools. A die, punch or the tool used to form it's resistance to cracking, breaking or chipping can be described as "toughness". Every material used in fabrication of a punch has its own properties for wear and durability. Those material choices range as follows:
Wear resistance is low, but high toughness
BALANCED wear resistance & toughness
High wear resistance and LOW durability
The specific application for forming will determine the material to select. Therefore, wear resistance will be affected by the hardness of the tool itself plus any additional coating applied.