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Life in the vacuum

A project log for brdMaker

Advanced Pick and Place machine

mika-heikkinenMika Heikkinen 05/18/2017 at 20:140 Comments

One of the basic functions of the PNP is ability to keep component in the nozzle.

This is done by the vacuum.

I have one real BGA station and nozzle vacuum is done there with the venturi effect.

Venturi effect forms vacuum from compressed air. It works very well, but consumes HUGE amounts of compressed air. As an example 2kW compressor runs almost full time. That's definitely the best choice is you are having free and silent source of compressed air. I don't like that noise so will look something else.

Another option is to use vacuum pump. There are numerous handy looking small dc pumps out there and many are using those for PNP.

I tried 3 types of dc pumps. Common to all of those was that those are terrible source of RF interference.

Some of those were so bad that i lost image from hdmi display completely. After switching back to VGA there was at least some sort of noisy image.

After placing pump into RF shielded box and added noise filtering into power it was possible to operate on the same desk. Well you can understand this well when you look that blue spark glowing from the burning carbon brushes.

Other worry with those small DC pumps was that those are not meant to run long times continuously.

Ok, we are not going running continuously, or are we.. Some people with more experience recommend that you should run continuously because motor may not start as fast as expected.

I decided to try something bit heavier this time.. AC vacuum pump meant for generating vacuum into air conditioning tubes. Those are meant to run hours at one go.

Seem to run very nicely and quite silently and generates good source of vacuum.

Pump problem solved, but new worries came around..0402 parts just have so small mass that those get stuck into nozzle.. There have to be some magnetic or surface forces that keep component in the nozzle event the vacuum is completely disappeared. It may not be the problem if the component is pushed into paste, but you can't imagine any discard functionality if parts keep hanging on nozzle.

First thought was that component now needs air blow from nozzle. Of course i could use compressed air there but there is that vacuum pump already running there.

Pumps exhaust happens from the oil cap. So after making proper adapter into oil cap, there was source compressed air. I added filter if there is plenty oil mist in the air.

Then another solenoid connects now compressed air into nozzle when needed.

All the valves does not work with the vacuum, so check this before buying any.,

Now part stays very well in nozzle, and drop very fast when pressure is applied.

HackADay: Tool holder wall is very handy when doing pneumatic breadboarding

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