Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Cleaning SMD Adhesives

#20833

Cleaning SMD Adhesives | 23 July, 2002

Is anybody "successfully" cleaning adhesives from the DEK Pump Print stencils?

Yes, Dave, I have searched the archives only to find comments ranging from easy to very difficult to clean. However, nobody states what process they are using. What chemical, what machine, cycle time, etc.?

We are using Loctite 3616 glue and Zestron in an ultrasonic cleaner and we still need to use compressed air, brushes and tooth picks to remove the fresh glue.

reply »

#20834

Cleaning SMD Adhesives | 23 July, 2002

Searched the Archives??? Gold star.

You're correct. I don't imagine there is much detail on actual cleaning process information. Mostly just top level ranting by our favorite stencil cleaner salemen. 'Ahem. Yes, it is VEEEERY important to select the cleaning medium to be used to clean your paste and adhesive before selecting the cleaning machine. bla bla bla.'

No 'DEK Pump Print'. No Loctite 3616 glue. No Zestron.

We clean Loctite 3906 with Hydrex [Petroferm] and [near as I can tell] follow the manufacturer's guidelines => http://www.petroferm.com/PTF-053/pdf/tds/petroferm/hydrexactds01-01.pdf

... expect that we use a spatula and stencil wipes [JNJ???] to prep the stencil before cleaning.

reply »

Mike Konrad

#20839

Cleaning SMD Adhesives | 24 July, 2002

Using ultrasonic technology to remove adhesive is normally not that difficult. I do not know who�s machine you are using (perhaps its ours).

In any case, here are some tips for removing adhesives.

1. Heated wash chemistry works better than ambient. If your stencil cleaning system is equipped with heaters, set them to 105 degrees F.

2. You mention that you are using Zestron. May I assume that you are using Zestron�s SC200? If so, are you buying the ready-mix or the concentrate? If it is the concentrate, what percentage are you using? I believe that 20% is the recommend percentage. You can verify the chemical concentration easily by using a hand-held refractometer. This will display the refractive index of your chemical mix. This will determine the percentage. Zestron sells an over-priced refractometer and others are available elsewhere (for less). Be sure to ask Zestron what scale to use. I would also recommend that you contact Zestron (www.zestron.com) (703) 589 1198. There chemicals are expensive but their chemical and process knowledge is very good. They will run tests with your adhesive and provide you with some advice.

3. Was there a time when the chemical worked better than now? If so, the chemical may be loaded. Zestron likes to say that the chemical will last almost indefinitely. Though this may be true in a lab environment, it is seldom true in the real word. If your stencil cleaning system is equipped with a wash-solution filtration system, the chemical will last longer. With the right amount of filtration and chemical attrition, your chemical may last almost indefinitely. Send Zestron a sample of the wash solution. They can determine the chemical loading.

4. Most stencil cleaning equipment have an adjustment on the ultrasonic generators called an amplitude adjustment. This is normally an adjustment of 50% - 100% output power. Be sure that the generator is turned up to 100% amplitude.

5. Make sure that your was solution is properly degassed before you use it. Normally, new wash solution must be degassed before it can effectively be used. Degassing can be accomplished simply by running the ultrasonic transducers for about 45 minutes each time the wash solution is replenished. Without proper degassing, the wash solution will not be effective.

6. How many watts of ultrasonic power does your machine have? The lowest powered machines on the market are equipped with 500 watts of power. Most machines are 1,000 � 1,500 watts. Some are even higher. Too little wattage (500 watts) may be ineffective in tough cleaning application while wattages greater than 1,500 may be too powerful.

7. Try another chemical. Although Zestron�s SC200 is normally very good, so are others. We make an adhesive chemical called StencilWash-AD, specifically for adhesives. Petroferm�s (www.petroferm.com) Hydrex WS series is also good. Kyzen (www.kyzen.com) also makes some very good chemicals.

8. Send me some of your paste and I have our lab test it with a variety of chemicals in an ultrasonic stencil cleaner. Perhaps we can find the right combination.

Mike Konrad Aqueous Technologies www.aqueoustech.com (909) 944-7771

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

reply »

Eric Chua

#20866

Cleaning SMD Adhesives | 25 July, 2002

Hello,

Understand you have problem of cleaning adhesives from Dek Pump Print stencil. Well, we have a cleaning machine which able to clean solder paste and adhesives. And also, we are not using any chemical but use water-base detergent. We had few customers using this machine to remove solder-paste and adhesives. This machine also can clean those misprint board / build board. For drying system, there is a drying chamber strong enough to dry those water under components.

You might like to visit our website :- http://www.cyberfurn.com.sg ( Look for Kolb )

Looking forward to hear from you.

reply »

#20931

Cleaning SMD Adhesives | 29 July, 2002

Dave,

Are you using The DEK plastic stencils with the 3906 or stainless steel? When we were using stainless steel, just about anything worked. It seems that the process for cleaning these *%#*&@" plastic stencils is either the best kept secret in the industry or else everyone is having the same problem I am having.

I even got a direct e-mail from a DEK applications engineer offering to help, but he offered no process. That tells me that either I'm the only one using these DEK stencils, or there is no process that works.

Oh, and our favorite stencil cleaner salesman forgot to change "solder paste" to "adhesive" in #8 of his canned response.

reply »

OhioD

#20937

Cleaning SMD Adhesives | 29 July, 2002

Interesting. From the reaction we got from DEK, I thought we were the only ones with pumpprint woes. We've tried 1 stencil with Bioact SC10, Hydrex SP&WS, Axarel, and Loctite remover on both Heraeus and Loctite glues. Some we spray, some we work-in manually (unfortunately, never tried ultrasonics). All we got is static build-up, plugged apertures, and a lot of hard work. It doesn't seem possible, but the plastic actually seems to attract adhesives, even emulsified adhesives. Then, we discovered PhotoStencil laminate steel stencils. The plastic stencil is now with the mesh screens and rubber squeegees in the back.

reply »

Mike Konrad

#21034

Cleaning SMD Adhesives | 2 August, 2002

Hi CarlN,

I�m quite surprised that you viewed my response to your question as a �canned response�. I discussed transducer wattage, transducer amplitude, chemical selection (more than just ours) in an effort to assist your in adhesive removal issue.

This was not an attempt to sell you anything since you already have a system in place. My advice was generic and my offer to assist you was sincere. Perhaps you are mixing me up with someone else who usually provides �canned�, sales oriented, knee-jerk responses.

Mike

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

reply »

#21335

Cleaning SMD Adhesives | 27 August, 2002

I finally found the answer!

I just got back from visiting Smart Sonic out in LA. They have a new chemistry that works great (220-A SMD Adhesive Remover). I took two DEK plastic stencils with me and spread them both with Loctite 3616 and the system cleaned them in less than 10 minutes. No residue - no stains - it even cleaned some of the old glue that had been on there for months. The stencils looked as good as new.

Now, I just have to work on the budgetmyster to get a system in here.

Thanks to all that replied, both on-line and by e-mail.

Carl

reply »

#21623

Cleaning SMD Adhesives | 18 September, 2002

Hello Carl,

Is the 220-A chemistry from Smart Sonic aqueous or a solvent? What do you plan to do with the waste water (solvent)?

reply »

KC

#22098

Cleaning SMD Adhesives | 23 October, 2002

Hi ,

DEK S'pore came out with a univeral frame called 'vector',that the stencil can be removed from the frame and soak into solvent for effective cleaning.

RGDS

JOSEPH

reply »

Alan Hobby

#22196

Cleaning SMD Adhesives | 30 October, 2002

I hope you'll take an answer from the sunny UK. I don't usually read these forums but contribute to similar over here, hence the late response. We have an Invicta Sabre 757 machine in our Demo room, running with Zestron SD 300. We give the PumpPrints 2 or 3 passes with both the under-liquid spray and the ultrasonics turned on, although the U/S isn't absolutely necessary. We clean all of the regular glues from Amicon, Epibond, Heraeus and Loctite. It works faultlessly, but the machine is inconvenient for short colleagues without a box to stand on. We use the same system to clean solder paste stencils and meshed screens. I have seen demonstrations with other solvents and machines that have worked pretty similarly. Hand cleaning is indeed troublesome. You need patience, solvent, compressed air and red or yellow trousers as appropriate. Try using a vacuum hose, with a bit of cloth or a wipe over the end of the tube, to suck most of the glue out of the apertures before starting with the solvent. At least you'll be washing all the way through, not just from the ends. If you are going to continue with the same stencil soon, you can probably leave the glue in the apertures rather than cleaning the stencil. Just scrape off the excess, DO NOT USE ANY SOLVENT because partial washing will begin to harden the glue, and pop the stencil into a bag to keep the dust off. You should satisfy yourself that this is safe to do but we have had good results after a couple of prints on dummy boards, using e.g.Heraeus 955 after 5 days of this storage at normal room temperature.

reply »

PCB Cleaning

SMT Equipment Service