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LED sticking into carrier tape

Views: 4790

#78556

LED sticking into carrier tape | 1 August, 2017

Hi all,

We are having a lot of trouble with mis-pick trying to place silicone dome LEDs(3535 package) It seems that the silicone of the LEDs is sticking to the side wall of the carrier tape pocket. The vacuum nozzle would normally suck up the led and center it, but since the silicone is sticking to the pocket, the led will not be lifted and a lot of mis-picks occur.

Any suggestions?

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#78557

LED sticking into carrier tape | 1 August, 2017

Are you using a custom nozzle meant for the domed LEDs? If not, that should help quite a bit and are less expensive than you may think.

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#78559

LED sticking into carrier tape | 1 August, 2017

Can you supply the following information to help with your question.

1. MFG P/N 2. Pick and Place machine being used 3. Type of nozzle and feeder being used on machine.

We place a wide variety of LEDs and had similar issues and have to use custom nozzles and modified feeder tape windows.

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#78560

LED sticking into carrier tape | 1 August, 2017

We are using a custom made nozzle, designed for this particular LED.

The dome of the LED is also custom made, the diameter of the lens at the base is 2.9mm while the substrate of the package is 3.3mm, so this gives about 0.2mm spacing between lens and side of package.

When the LED is sticking against the side wall of the pocket, there is only 0.2mm of space for a nozzle that fully slides over the dome.

I am suspecting that the nozzle we use now (a square shaped nozzle) is either hitting the lens in this case, or it has too large of a vacuum leak because the opening needs to accommodate for LED position in the pocket.

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#78563

LED sticking into carrier tape | 1 August, 2017

There is one thing to be checked too. That is to make sure the nozzle not going too deep when lower to pick up the part. I found a lot of picking errors issues are due to nozzle going down too deep into the pocket. If it does, it pushes the components down against the bottom of the pocket; but when the nozzle trying to lift the part, the pocket bottom would bounce back, causing the part to drops. This is especially common for emboss tapes since it's flex more than paper. Try to adjust how deep the nozzle going down, so it barely touching or almost touches the part. Also, slows down the picking speed a little and increase vaccum and try it. That might solve some picking issues.

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#78564

LED sticking into carrier tape | 1 August, 2017

Agreed with Thomas i increase wait time when picking and slow down Z axis. If you think it is the tape, I would suggest you send one tape to a company that puts parts in tape. let them use different pocket and compare result. If the part is sticky and you can't get it out of the pocket, you should address that with the manufacturer.

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dwl

#78565

LED sticking into carrier tape | 1 August, 2017

A quick and dirty test;

Take a few inches of carrier tape, peel off the cover, gently turn it upside down and see if any of the parts stay in the tape.

If they do, then you know there's an issue with the tape.

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#78566

LED sticking into carrier tape | 1 August, 2017

Try the method I mentioned earlier, it greatly improves most of the picked-but-drops issues. We never need to use any custom make nozzles, even for the trapezoid dome shaped LED we were having the issue with. Use smaller round diameter nozzle would do just fine too. Just sucks on the very top portion of the LED, with enough vacuum it will work, doesn't have to slide over the whole dome with the bigger nozzle.

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#78585

LED sticking into carrier tape | 2 August, 2017

We did this test, we opened the tape and turned it upside down, indeed some leds were staying inside the tape.

We will try placing them next week with a fuji NXT line. We also contacted the manufacturer, apparently heat perhaps during transport could be causing this issue, softening the silicone.

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#78586

LED sticking into carrier tape | 2 August, 2017

Are the parts kept in a humidity controlled environment ? Perhaps a little humidity is making the silicon "sticky".

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#78605

LED sticking into carrier tape | 3 August, 2017

I did a test where the leds were put into a 95% humidity at 60 degC environment for an hour, and after that almost all leds would stick into the carrier tape. So, moisture might certainly play a major role in the stickiness of the leds. We placed all remaining leds in a drying chamber now, next week we will perform a new test.

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#78614

LED sticking into carrier tape | 4 August, 2017

One tip that I found very useful in this application that hasn't been mentioned is auto pick up position teach. Our Panasonic equipment will constantly move the pick up position in regards to the center of the nozzle when scanned. On older Panasonic CM and DT equipment you simply enter a small offset in the part data. On NPM machines you can turn in off in the options.

Turning up the vacuum helps too.

Hope this helps.

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#78711

LED sticking into carrier tape | 16 August, 2017

What was the outcome OrHorti after baking some?

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#78809

LED sticking into carrier tape | 1 September, 2017

> What was the outcome OrHorti after baking some?

In the end we went with a different machine (Fuji NXT) which was able to get the leds out of the reel. After switching we still face a loss of about 0.5% but it is acceptable for now.

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#78816

LED sticking into carrier tape | 4 September, 2017

https://youtu.be/aMyoQK_c3hE Did you find the solution?

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#78836

LED sticking into carrier tape | 6 September, 2017

You need to slow down the machine for starters.

Try rotating your nozzle so that the touches the least amount of silicone membrane as possible.

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