Summary for sla plastics activation Discussion
SLA plastics activation for electroless coating is the core issue here: Martin Lefebvre, working with Somos PerFORM SLA resin for optical instrument parts, says he has been using KOH etching before Pd activation and electroless NiP or Cu, but sometimes sees adhesion failures in scotch-pull testing. He asks for safer alternatives to the older sulfuric/chromic acid etch, which he wants to avoid because of chromic acid toxicity and REACH concerns, and says he is testing acids such as nitric and sulfuric while varying time and temperature and checking SEM and contact angle. The only response shown does not offer a plating recipe; instead, Ted Mooney warns strongly about hydrofluoric acid, saying never to use HF unless trained and to have antidote gel available immediately, specifically calcium gluconate for HF burns. The excerpt therefore emphasizes safety around HF rather than a proven activation method.
Q. Hi there :)
I am a researcher in Europe involved in optical instrument development. I’ve been investigating PLD-SLA resins for complex parts that can’t be produced with classic machining. I am especially working with the Somos PerFORM produced by Stratasys.
So far, I’ve been activating this resin using chemical etching with KOH before a Pd bath and electroless plating with NiP or Cu. I’ve been observing adhesion defects with a scotch-pull test from time to time.
I am looking to improve the etching phase: In the past, a documented approach has been to use a mix of sulfuric and chromic acid. This is out of the scope due to the very high toxicity of chromic acids and the European REACH regulation.
I would like to know if some of you have been working with this type of SLA resin and have tried to activate it. If so, with which products ? Do you have any advice ?
My approach is currently is to try several types of acids such as nitric acid, sulfuric acid and changing temp/time, and make SEM observations of the surface and droplet contact angle measurements.
Thanks a lot!
Have a good day all
Martin Lefebvre
Researcher – Marseille, France
February 20, 2025
Hydrofluoric acid burns
Never use HF anywhere unless trained!
If you do, you MUST have the antidote gel on hand for instant use!
Calcium Gluconate
for HF acid burns
on Amazon or
(affil link)
A. Hi Martin.
The reason that ABS is the favored resin for plating onto is that it contains three polymers, one of which forms tiny balls which dissolve in chromic-sulfuric acid, leaving a sponge like surface for outstanding adhesion.
It isn’t clear to me the constitution of Somos Perform, but it sounds like it has a high ceramic content such that hydrofluoric acid might be an effective etchant.
As far as I know hydrofluoric acid is not prohibited in the European Union, but it is way more dangerous than chromic acid — don’t use it except with calcium gluconate gel on hand.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
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