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how to measure Adhesive strength

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#58769

how to measure Adhesive strength | 11 May, 2009

Hi, I just want to know how to measure the strength of a 0603 after it's cured, we are using Heraeus PD944 with a 30-7 mils stencil, glue depositions looks well, but I don't know how to measure it? Thanks

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#58770

how to measure Adhesive strength | 11 May, 2009

What is the purpose of glueing it?

If it is glue the bottom side parts followed by reflowing the top side parts followed by wave soldering the bottom side parts, then it's easy to measure.

Hold the board with the 0603s facing down. If they don't fall off, it's strong enough.

If you are doing it for some other reason then it depends on the purpose.

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#58773

how to measure Adhesive strength | 11 May, 2009

Yes, this is for a double sided board, (bottom) the issue is that the board has a lot af hand ion components before wave soldering, and some components are falling off within this process, even if I hit the 0603s with my finger It falls.

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#58778

how to measure Adhesive strength | 11 May, 2009

We'd expect that a 0603 in properly cured, in-date code, properly dispensed chip bonder would take 5-8 pounds to push off the board.

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#58781

how to measure Adhesive strength | 12 May, 2009

Jorge,

The basic thumb rule to measure Adhesive Strength remains as bonded Chips at Post Reflow should not move around or misplace when Your Thumb Finger try to do so which called as Thumb Force Test.

However as Dave stated, there are various Strengths in Push Pull Tester to be applied according to the Size & Type of SMDs which typically would not be in place with everyone.

Tnx, David. India.

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#58816

how to measure Adhesive strength | 15 May, 2009

We've used PD944 for years with excellent results. Our uses include everything from wave (passives) to holding large, heavy SMT parts (e.g. connectors) that run on pass1 and are then suspended on pass2. We've never applied it with a stencil, but we have auto-dispensed, manually dispensed and even applied it with a scribe.

Make sure you're meeting the time/temp reqt's for curing. There's a wide range (lower temp/long time > higher temp/shorter time). Solder mask may be a factor as well. I've seen parts get knocked off where the glue is still affixed to the part, along with a nice piece of solder mask from the board. If you can knock a part off with casual contact, there's something going on that doesn't require measurement.

Good luck, Jorge.

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#58817

how to measure Adhesive strength | 15 May, 2009

Use loctite chipbonder and forget about all this pull testing. I know that Loctite works good because it pulls a chunk of solder mask off the board when you push a part off.

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#58857

how to measure Adhesive strength | 20 May, 2009

Use a push/pull tester. I use an OBA inst. works Ltd. tester. Just because mask comes off with bonder doesn't mean bonder is strong or cured right. Mask can be weak in between pads do to area size. Do it right and you'll know for sure. To many people guessing here.

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