How do I prep my board for a pick n place machine?

Chat about pick and place machines, reflow ovens, assembly techniques and other SMT tips & trix

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josheeg
 
Posts: 213
Joined: Wed Jan 16, 2008 8:38 am

How do I prep my board for a pick n place machine?

Post by josheeg »

How do I prep my board for a pick n place machine?
I seen ones with a O with a t in the center of it on the silk screen is that how?

What are the home options?

What are the mail my boards and parts out or select correct parts and send a bill of materials options?

Any good tutorials on this?


josheeg
 
Posts: 213
Joined: Wed Jan 16, 2008 8:38 am

Re: How do I prep my board for a pick n place machine?

Post by josheeg »

That is a good tutorial & it mentions 1mm exposed pads. for reference
clearance on edges
4mm cog holes
v grove & routing
a detailed check list would be nice with dimensions.

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ktownsend
 
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Joined: Thu Nov 05, 2009 2:18 am

Re: How do I prep my board for a pick n place machine?

Post by ktownsend »

Those circular marks are called fiducials and you absolutely need them to accurately place anything since at the beginning of assembly an overhead camera measures at least two of these (which should be placed in opposite corners of the board) and determines and X/Y variations in rotation or placement from the ideal placement 'model'. There are 1mm fiducials in the adafruit library as a starting point. Size isn't critical, but 1mm is a pretty common value that doesn't take too much space. These fiducials absolutely need to be on the copper layer and exposed ... silkscreen is just for convenience and terribly unreliable for placement.

Make sure you have 4*3mm mounting holes since some pick and place machines use these to hold the board in place, and most solder paste stencil holders also use them.

Unfortunately, it's a trial and error learning experience as well. There are 50 things to get right but you kind of learn by doing in this case, as with PCB layout or other manufacturing and design tasks. It's a very iterative learning process.

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