There are many, many plating tips and secrets of the trade that one learns throughout the years. You may have heard some of these, but following are a few key pointers to keep in mind. They could save you a lot of time and aggravation down the road.
Avoid using chrome when molding with polyvinylchloride (PVC). Chloride is a component used to strip chrome off of steel; therefore the chrome will slowly dissolve due to the gases emitted from the chloride in the PVC. There is an old school of thought that chrome is better than nickel. Don’t believe it in this case.
Polytetrofluoroethylene, or PTFE, breaks down at 550xF. If you are using a molding application requiring mold temperatures that exceed this level, avoid PTFE and go with nickel or chrome. The PTFE, though useful for release, will break down and shut you down. It is not a bad idea to occasionally use different combinations of plating. Depending on what kind of performance you require from your mold, consider having more than one plating material for optimum efficiency. For example, if you require abrasion and corrosion protection, a base layer of electroless nickel (for corrosion) and a top layer of hard chrome (for abrasion) are recommended. The two work together very well.
Technology now allows us to skillfully and effectively mask off even the most remote areas of a mold so that very localized plating can be applied. Selective plating with electroless nickel, for example, is a great way to correct size on threaded cores or slides for ring necks threads. This application is good for corrections under .004 inch per side. Need just abrasion protection? Go for hard chrome with a heavy flash of between .0004 and .0006 inch – especially if you are using glass-filled materials.
If corrosion protection is needed, an electroless nickel .0002 to .0004 inch deposit is an excellent choice. If corrosion protection and release is needed, a co-deposit of electroless nickel and PTFE – 25 percent by volume – is a proven combination.
When selecting electroless nickel for rubber molding, we have seen sulfur-cured materials still unwilling to release, so a heavy topcoat of PTFE is usually required.
An effective use for chrome is shimming or correcting for size on inserts, cavities and cores. You can mask and selectively plate the parts up to a .020 inch deposit, finishing it with either grinding or EDM.
As always, when choosing plating you need to know what type of steel grade and what plastic material will be molded. Communicate these details to your experienced plating house and, based on your molding requirements, you will have the ultimate finish on your molding surfaces, saving you time and money and producing the high quality parts your customer expects.
Related Industry Knowledge
- Plastic Mould
- Introduction to Plastic Mould
- Main classification of plastic moulds
- Structural elements of plastic moulds
- Material requirements for plastic m...
- Material selection of plastic mould
- Technical application of plastic mould
- Mold Development
- Injection mould
- The composition of the mould
- Important Considerations for the Ej...
- Mold Trial Steps
- Mold Trial Instructions
- Moldfolow Analysis Will Help Avoidi...
- Different plastic molding process
- Plastic Injection Molding
- How to design the main insert size ...
- What is the return pin and how the ...
- What is the ejector block in plasti...
- How to improve the heat treatment d...