Plastic Mold Steels
|Average pore size: 7 or 20 microns
Porosity: 25% air by volume
Linear Expansion: (@68 - 302°F) 6.67 - 6.94 in./in F
Heat transfer co-efficient (at room temperature):
16.93 - 19.35 BTU/ft. hr. F
Tensile strength:63990-71100 lbs./In2
Hardness: HMV 350 - 400 (35-40 HRC)
HSS Machinability: Good
Machining and Polishing
Porcerax II can be machined by conventional methods using cutoff saws, end
mills, grinders, EDM methods, stoning, etc. It is important to remember that
this material is honey-combed with thousands of microscopic holes which are
affected by metal removal. Oil coolant is recommended.
Grinding closes the pores of all grades of this porous steel. Milling will
close the pores of 7 micron and reduce the pore size of the 20-micron material
down to about 7 microns
(when done correctly) by partially closing the pore opening at the surface.
Stoning, using a back and forth/side to side method, will re-establish
permeability by removing the metal that is crushed over the pores. Stoning and
polishing, up to about a number 800 - 1000 stone/paper finish, is possible.
During the stoning and polishing process, it is important to occasionally
flush the pores at the surface to prevent packing the pores with debris.
Electric Discharge Machining is the best way to re-establish permeability.
This method will burn away the metal fragments that are crushed over the pores
by milling and/or grinding.
Note: When using wire EDM machining methods, Porcerax II is porous and
waste particles that can create "arcing" conditions between the wire and the
This arcing can cut the wire. As a countermeasure, increase wire winding
Note: When using an electrode for EDM, it is important to program a
peak-to-valley burn rate that exceeds the pore size; i.e. < 7 micron depth for
7 micron pore size is desirable.
The illustrations above show how particles created by the wire EDM process
electrical current across to the work-piece, creating the potential for a
discharge that can break the wire. Increasing the wire winding speed not only
greatly reduces the potential for wire breakage but also increases machining
It is imperative that anyone coming into contact with Porcerax II during the
mold building or molding operations understand the characteristics and
sensitivity of this material. Any questions should be directed to International
Mold Steel at 1.800.625.6653.
All technical and engineering data and suggested procedures, specifications and
applications contained in this publication are for general information only.
Sintokogio, Ltd., International Mold Steel and/or their distributors disclaim
any and all express or implied warranties of merchantability, suitability for
any particular purpose or use, or freedom from infringement of any patent,
trademark or copyright. Porcerax II® is a registered trademark of International
Mold Steel, Inc. and Sintokogio, Ltd..