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I just got access to an SMT machine in a DIY fablab. I have a board that has about 50 unique components that I wish to assemble and test drive this new machine. I intend to make 20 of these boards. How should I go about it?

Do I load the 15 of the 50 components and have them put on the 20 boards or cycle through the components and complete one board at a time? My boards are not panelized since I was planning on assembling them by hand so I think would either have to take the boards out or the components. Looking for any practical advice on this.

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    \$\begingroup\$ If you could modify the circuit to only need 45 distinct components, you could cut it down to just three runs in future. For example, if you had lots of 10k resistors and just one at 5k6, perhaps two 10k resistors in parallel would do. \$\endgroup\$ – Andrew Morton Nov 21 at 12:02
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    \$\begingroup\$ Provided there is enough room, you could "re-panelize" them onto a backing carrier. But you'd still be looking at multiple runs and multiple re-toolings. \$\endgroup\$ – rdtsc Nov 21 at 13:18
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    \$\begingroup\$ perhaps you could place the most numerous, or hardest parts by machine and finish up with hand soldering \$\endgroup\$ – Jasen Nov 21 at 20:13
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Most contract fabrication houses would load up all their feeders and then make the run of boards for those components and then cycle back through the boards for the next load of components in the feeder. There are practical limits however including how many boards the factory can stage at one time, how long the solder paste stays able to accept additional components and how long the feeder change over takes.

In some factories you may see several pick and place machines in series on the line so that multiple sets of feeders can be active at a time to accommodate boards with very high BOM line item count.

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    \$\begingroup\$ That's how the board factories do it, but the question is how OP should do it. There's access to a DIY fablab with SMT, not a factory. \$\endgroup\$ – Mast Nov 21 at 22:56
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You feed the batch through the machine 4 times.
Solder paste has hours from application to soldering, it will be fine.

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