Hi, our 0402 parts sometimes stick to the nozzle. After being lowered into the solder paste, the nozzle moves upwards with the part still attached (although the vacuum is off by then). We tried increasing the put delay which lead to a slight improvement, but the problem still occurs sometimes. We also cleaned the nozzle with Isopropanol and exchanged the nozzle by a new one, but this does not help. Furthermore we decreased the part height, so that the parts are pushed further into the paste (but without improvement). The nozzle size is CN040. There is also enough solder paste on the pads. Is there any way of making sure the part is not sticking to the nozzle anymore? Best regards, Bienja

we did clean the nozzle with isopropanol and also tried using a brand new nozzle. but it still happens...

After installing the components for a few boards it was discovered that the components, that were installed by the first knob, are biased because of "jumping". It was discovered that both pressure regulators of vacuum cutoff were twisted in the beginning, and safety nuts were pressed to the heads of regulatory screws, which were freely dangling because of that.

The cutoff's pressure on the second head with maximum opened adjustment valve was present, while on the first head it didn't.
As the result of analysing this malfunction it was found that the length of pneumatic tube, which connects the vacuum valve with an ejector, is not enough for creating a normal pressure of the cutoff. The malfunction was eliminated by extending the specified connecting tubes to about 30 cm. After this the vacuum cutoff began regulating normally by corresponding regulators on both knobs.


VP-2800HP.

Hi Michael,

We are having this same problem with 0402 parts sticking to a CN040 nozzle. Of the 4 nozzles on one of our VP-2800HP-CL64-4R machines, it only happens to one of the nozzles. It doesn't happen on the other three nozzles at all. We have tried cleaning the tip with isopropyl alcohol, switching the nozzle from #3 to #4, and using a brand new nozzle. But it still will randomly stick about 1 in 20 parts. I tried adjusting the needle valve, but it was already at the farthest open setting from the factory. Is there anything else we can try to get this to be more reliable? Luckily since this is happening on nozzle #4 we can just change the placement settings to only use nozzles 1-3, but our panel build time went up to 45 minutes from 35!

Thanks,

John

There was the same problem on VP2800HP
I have lengthened the air tubes laided from the valves to the ejectors by 20-30 centimeters.
Helped very well.
After that, you just need to carefully adjust the needle valves.

Thanks for the help SergOv.

I don't completely understand your description. Would you be able to post a photo of which air tubes need to be lengthened? Thanks!

Thanks for the help, Michael and SergOv. After playing with the solenoid valve and seeing what lines where pressurized at different stages I now understand what you mean. I will be elongating the tube shown in the photo to get more push. IMG_0644.jpg - Bild entfernt (keine Rechte)

Yes, it are these pipes.
Extend them by about 2 times, then use a needle valve to adjust the pressure after vacuum cut-off.