m8ta
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{422} | ||
For the past few days I've been trying to figure out a way to do vacuum-assisted pick & place for home SMT PCB assembly. Fortunately, I had a vacuum pump - this one bought, without motor, from now defunct Duke University Surplus for $25. I got the motor from my parents, and had to go to Northern Equipment for the pulley and belt (fyi: also bought a hot air gun, Wel-Bilt brand, which promptly broke upon testing at home.) I filled it with 10w30 synthetic motor oil, since some of original vacuum oil had leaked out during the (years?) of neglect at the surplus store. The whole assembly was far heavier than i could move, so i welded together a little cart for it out of old sideskate axles & bed frames. The wheels are from a cheap wal-mart skateboard that i used like 3 years ago to make the pogoboard. I also had to figure out how to neck down the 1.5" vacuum port on top of the huge pump to 1/4 id tubing, which took about 15 mins of searching in home depot... Above - Valves clamped to the table so i can operate them with my right hand while my left hand manipulates the fine SMT devices. Top valve is to control the vacuum pressure, bottom is a dump valve to release vacuum in the tip. I used three hypodermic needles, of varying diameter, as the tips for picking up small items. For the large chips, e.g. 176 pin LQFP-s, I ganked the ink tube out of a ballpoint pen. & glued it to the syringe connector (which is nice and easily replaceable). All tips were ground down at about a 40 deg angle to hold the parts (and to make the tips dull enough so i wouldn't continually stab myself while working...) simple and effective! see also {423} |