I believe that the right silicone based PSA would work fine. No one is more concerned about contamination than plating shops. "Plater's tape" is a mylar carrier with silicone adhesive. It's used in PCB fabs all of the time. But I guess the silicone is in a highly stabilized form that doesn't leach oil like the masking dots Phil is mentioning below. I've used DuPont Kapton tape with silicone adhesive, and I've never had an oil leaching problem. Not good stuff for masking because the polyimide material itself causes the paint to bead up.
When I opened an R&D board fab lab, I chased out all silicone based compounds. So I learned about how bad the acrylic PSAs are: Those tapes drop little globs of acrylic PSA EVERYWHERE. True, they don't cause de-wetting like silicone has the potential to do, but they block plating where they've decided to stick anyway. If you want a real nightmare try plastering those danged "Post-It" notes on everything: the weakening done to allow them to be easily re-positioned frees up the acrylic globs.
Anyway, this is a divergence because for relatively crude masking applications on surfaces that don't have to be perfectly clean, standard painter's materials are fine if you can address the static.
Wayne
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Craig Sullivan
Sent: Monday, June 19, 2017 1:58 PM
To: [log in to unmask]
Subject: Re: [TN] Conformal coat tape of acrylic
Phil,
Yes, I agree. I am not even looking at anything with a silicone adhesive. I've been extremely cautions not to introduce silicone into our process over the years. I've even gone as far as telling the tape slitters not to use the silicone solution on their blades when slitting our orders.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Nutting, Phil
Sent: Monday, June 19, 2017 4:26 PM
To: [log in to unmask]
Subject: Re: [TN] Conformal coat tape of acrylic
Craig,
We use Konform AR and at some point our acrylic adhesive masking dots were discontinued and replaced with a silicone based adhesive. The silicone worked, however I saw an odd fish eye pattern and blooming under UV light around the dots. You could watch the blooming as it cured.
My 2 cents is to test the new mask materials with your coating and watch under UV light.
Phil Nutting | HVP Development Engineer | Excelitas Technologies Corp
Lab: +1 978.224.4332 | Office: +1 978.224.4152
35 Congress St, Salem, MA 01970 USA
[log in to unmask]
www.excelitas.com
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-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Craig Sullivan
Sent: Monday, June 19, 2017 1:31 PM
To: [log in to unmask]
Subject: Re: [TN] Conformal coat tape of acrylic
Thank you. I’ve requested samples of those recommended. Much to my surprise, I also found some on Humiseal’s website so I asked for samples of that as well.
Steve: Yes, we go through rolls of that as well. But we have a couple of new assemblies where it’s giving us issues for some reason. I first thought it was cleanliness, then possibly just a bad lot of tape, but I’ve exhausted those conditions.
Craig Sullivan
Manufacturing Engineer
IT Administrator
Phone: (607) 266-0480 x115
Fax: (607) 266-0482
Email: [log in to unmask]
Web: www.mplinc.com <http://www.mplinc.com/>
MPL, Inc.
41 Dutch Mill Road | Ithaca | NY | 14850
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From: lduso - Diamond-MT.com [mailto:[log in to unmask]]
Sent: Monday, June 19, 2017 12:29 PM
To: TechNet E-Mail Forum; Craig Sullivan
Subject: Re: [TN] Conformal coat tape of acrylic
3m Green Tape 233+. The most common size we use is the 3/4", p/n 26334. Slightly stronger adhesion than the blue. We still stock the blue for masking delicate components, like radial resistors, specifically because it has low adhesion and there is less chance of damaging the components on demask.
Lloyd Duso
Plant Manager
Diamond-MT
(814) 535-3505
www.Diamond-mt.com
On Mon, Jun 19, 2017 at 11:59 AM, Craig Sullivan <[log in to unmask]> wrote:
What masking tape is everyone using for Type AR coatings?
Long story short:
We used to use the St. Gobain M797 which was also known as Humiseal's HT-500. Due to numerous manufacturer issues, we stopped using it.
One of our customers spec'd in the blue 3m painter's tape and we have been using it successfully for a while.
We have some new assemblies where the 3m adhesion is terrible and am now back onto looking for a new tape, similar to what we all went through some 8 years ago.
Craig Sullivan
Manufacturing Engineer
IT Administrator
Phone: (607) 266-0480 x115
Fax: (607) 266-0482
Email: <mailto:[log in to unmask]> [log in to unmask]
Web: <http://www.mplinc.com/> www.mplinc.com
MPL, Inc.
41 Dutch Mill Road | Ithaca | NY | 14850
An ISO 9001:2008 Certified and ITAR Registered Company
IPC member since 2004
_____
Confidentiality Notice:
This e-mail contains privileged and confidential information which is the property of MPL Incorporated, intended only for the use of the intended recipient(s). Unauthorized use or disclosure of this information is prohibited. If you are not an intended recipient, please immediately notify MPL Incorporated and destroy any copies of this email. Receipt of this e-mail shall not be deemed a waiver by MPL Incorporated of any privilege or the confidential nature of the information.
Export Control:
This message is intended only for the addressee and may contain information that is company confidential or privileged. Any technical data in this message may be exported only in accordance with the U.S. International Traffic in Arms Regulations (22 CFR Parts 120-130) or the Export Administration Regulations (15 CFR Parts 730-774). Unauthorized use is strictly prohibited and may be unlawful. If you are not the intended recipient, or the person responsible for delivering to the intended recipient, you should not read, copy, disclose or otherwise use this message. If you have received this email in error, please delete it, and advise the sender immediately.
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