Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Electroless Nickel Plating of Steel Molds
2001
Q. Dear All:
We need to plate with Electroless Nickel some plastic injection molds. The main reason is to protect from hydrogen to get out.
My questions:
1. If it's correct to plate with nickel to that destiny?
2. There are special (plastic) row material that unique to this plating?
3. What is the recommended thickness for this destiny?
Thanks and best regards,
- Israel
A. Dear Meir:
When you say avoid hydrogen to get out do you mean from the plastic or from the mold substrate? We have been plating plastic molds for automobile and other industries for over 6 years mostly for corrosive plastics such as ABS, PVC or CPVC. I need more specific info to help better.
Monterrey, NL, Mexico
2001
Mold release problem for rotational molding process
Q. Hi,
I have a small factory for producing water storage tanks.
I am using steel molds in the rotational molding process to produce the tanks using powder form of LLDPE, at 230 ° C.
I have a release problem in my work. I am looking for a suitable kind of teflon coating to the inner surface of the mold to improve the release of the product out of the steel moulds, can anybody tell me about the suitable type and the coating process to solve my problem.
- Ramallah, West-Bank
2006
A. There is a process that deposits Teflon particles embedded in an electroless nickel matrix which is best for your application. Second choices would be plain hard chrome or electroless nickel. Since your molds are perhaps rather large, it may be hard to find a supplier that has the required size tanks and capabilities. On the other hand, if your molds are not required to remove lots of heat very fast and the surface finish is not of paramount importance, maybe a sprayed-on teflon paint over a well blasted surface might last enough to be cost effective.
Guillermo MarrufoMonterrey, NL, Mexico
2006
Q. Thank you Mr. Guillermo Marrufo, I do really appreciate your answers. In my application process I need to cool down the molds from
230 °C to the ambient temperature in about 20 minutes, using moist cooling air. The surface finish of the product should be even and nice looking; i.e. acceptable to the customer.
NOW, according to the above mentioned, which one is better, The sprayed-on teflon paint, or the process that deposits Teflon particles embedded in an electroless nickel matrix?
Thank you,
- Ramallah, West Bank
2006
A. Electroless nickel (EN) either plain or composite with teflon (CEN) as well as chrome, develop a molecular bonds to most metallic mold surfaces, they replicate the finish and are very smooth and durable. CEN is expensive and hard to find a shop that can handle large molds but its performance is best. Teflon paint, on the other hand, tends to rely on a mechanical bite or anchor pattern to obtain a fair adhesion to the mold. Thus, the mold surfaces have to be blasted. A good processor may render a product similar to that of a Teflon fryer pan. It is cheaper and size may not be an issue but heat transfer may. Hard chrome and plain EN are in between in price, performance and durability. Good luck.
Guillermo MarrufoMonterrey, NL, Mexico
2006
Q. My end product is a silicone molded eye implant. I want to do plating to get fine/shiny surface finish implant after molding. Any one can suggest the permanent plating method for the mold so that the plating/costing won't peel off after some time and stick to the molded parts.
RajasekarPlastic/ silicone rubber medical device manufacturer - Madurai, TN, India
December 29, 2012
A. You do not mention what is the base material of your molds but properly applied electro-nickel or electroless nickel will not peel from conventional steel materials in a long time and both will resist corrosion and take a superb mirror finish. Chrome is harder but less resistant in case you process is extremely corrosive.
In any case, electroformed nickel or nickel-cobalt molds are a very good alternative to steel for molds that require outstanding corrosion resistance, good polishability and hardness.
Monterrey, NL, Mexico
January 10, 2013
Q. Hello. What thickness of electroless nickel do you recommend to withstand corrosion on a steel mold that will have high pressure PVC injection?
Camilo pagesMolds - Mexico City, Mexico
March 6, 2019
A. I would recommend .001 minimum of high phos electroless nickel for this application to withstand the processes.
Tyler ThomasT- Minneapolis, Minnesota, USA
March 20, 2019
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