Thread: Robin's smt Pick and Place build
Robin, it's been a while and the weather has warmed up over there.. any updates?
Then I had decided to forget everything I 'knew' about tape feeders and start again. It was a liberation, I have the basic ideas, but designing that perfect lever system takes time :whistling:
hello.. just wondering, how do you compute for the correct nozzle type for a specific product? is there a standard computation for the nozzle inner hole?
hope someone could answer..
I don't think you can do it simply as area * vacuum differential > mass of the component.
If you look at the tip it is cut to leak air. Bernoulli tells us that when you force air through an orifice it will try to close that orifice. Perhaps leaky is extra sticky.
so how do you generally select the type of picker that must be use?
Aim for the largest that you can reliably pick the part with, allow for the worst case resolution on your tape feeder as well as the nozzle placement.
If physically aligning the part on the nozzle you may need to snatch it back when the tapper opens so a good flow rate helps.
OTOH, if you don't have an autochanger you may decide to compromise on a single tool that picks your entire selection of discretes.
Suck it and see
I too am working on a DIY SMT pick and place machine and I've found your work very inspiring.
Can I ask, where did you source the small linear slide for the Z-axis, the leadscrews and anti-backlash nuts from? Also, what shape Z-axis cam are you using?
I got the parts off ebay. The Z cam is an eccentric, miniature ball bearing running on an iron rail. Has to be iron so it can't dent.
I got stalled by an old trap called, "The enemy of a good idea is a better idea". I got a notion that I could put the 8mm tapes really close together and lots of them. It goes like this... Mounted at one end of the X rail is a pin feeder and rubber pad. As the placement head moves over the component to be picked it drops the pin and winds if forwards, drops the pad on the cover tape and moves it back. As the placement head leaves it lifts pin and pad then resets them for next time. I am just waiting for the mechanism to pop into my head.
Good luck with your machine.
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