For many injection mold companies, electroplating is the way coatings have always been done.
Companies in the U.S. have worked since the 1800s to hone electroplating processes and today it’s one of the most popular injection mold coatings available. It increases abrasion resistance and has high hardness when done right.
However, you may be missing significant cost savings, performance improvement, and efficiencies if you’re only using electroplating.
Physical Vapor Deposition (PVD) is an increasingly popular alternative to electroplating that also increases abrasion resistance and assists in part release. According to the Rockwell Hardness measurements, it’s as hard as electroplating as well.
Picking the right coating for your molds can be a tricky process. There are two ways to approach the decision:
1) Consult a professional who can address your specific needs. We just happen to be one of those, if you want to hit that link and fire up a conversation.
2) Keep reading to make an informed decision.
Electroplating Vs Physical Vapor Deposition (PVD) Coating
What is Electroplating?
The tool is placed inside a liquid solution and connected to a cathode, or negative pole of a power supply (think negative wire to a car battery). The material you wish to coat the tool with is connected to the anode, or positive pole, and placed in the solution, too.
The negatively charged tool attracts ions from the positively charged coating material, and a layer of coating is formed. The tool is left in the solution long enough to attract the desired thickness of coating, then removed. The longer the tool is left in, the thicker the coating.
Popular coating materials include chrome, gold, silver, nickel, and copper. It should be noted that these materials can, and in many cases should, be applied in several layers depending on the material your tool is made of. For instance… if you have a silver tool, you’ll likely want to coat it with copper and nickel to give it the proper strength.
You can not plate certain materials like titanium, aluminum or polymers with electroplating.
That leads us to PVD.
What is Physical Vapor Deposition?
PVD coating is a process whereby the tool is placed in a vacuum chamber with the coating material. The coating material is then vaporized and applied to the tool as a coating. To ensure the tool is completely coated, it is rotated and repositioned during the PVD process.
What’s unique about PVD is that the coating becomes part of the mold. Where most mold coatings crack or wear with time, PVD mold coatings form an atomic bond with the tool that can’t easily be broken.
If electroplating is like dipping an egg in gold paint, physical vapor deposition makes it like the chicken laid a golden egg.
PVD coatings of Titanium Nitride or Zirconium Nitride, specifically, help with corrosion and wear prevention and release of parts from the mold. And importantly, because the coating is only 3-5 microns thick (less than half a millimeter), it won’t knock tools out of tolerance, which is a major pain for many companies who use electroplating.
(As a bonus, PVD can be used to apply a first layer to the tool, then electroplating can go on top of it for materials that don’t etch well together. Schedule a time with our technical team to see if this describes your situation.)
What they have in common.
Electroplating hardens tools, increases their resistance to abrasion and wear, improves part release, and enhances life span.
PVD does that too.
So how do you choose?
Choose the Tool That Saves You Time
If you opt for electroplating, you’ll need to consider how to construct the tool given the thickness electroplating will add to it. Time will also be spent masking the parts of the mold you don’t want coated. This added preparation work increases financial cost and turnaround time.
After the electroplating is done, it’s common for the coating to bleed into areas not properly covered by the masking. Many companies are disgruntled to find that their tool’s once sharp edges are now rounded with a thick plate.
Then there is the post-surfacing process, where the tools need to be reworked so that it has the right surface.
With PVD none of these considerations are necessary. That’s because PVD coatings are 4-10x thinner – meaning you can coat an entire tool without knocking it out of tolerance, without masking and you don’t need the post-processing resurfacing.
It can go from the vacuum chamber straight to assembly.
Your Needs Matter Most
At the end of the day, you need an injection mold coating that will preserve your mold, maintain efficiency, and save you time. While the evidence suggests Physical Vapor Deposition will do this best, it’s always a good idea to chat with an expert who can evaluate your unique situation and recommend a solution.