Electronics Forum | Wed Jan 03 23:00:18 EST 2007 | new guy
I'm a new guy in this field. I have a question about solder paste process. Is there any effect to the solderbility if we do a lot of contact to copper pad without using any insulation ( direct to the finger ). Where can i get information about smt pr
Electronics Forum | Tue Mar 20 15:59:15 EDT 2007 | blnorman
We use preprinted labels and laser coding. For PCB we laser mark with CO2 (NdYAG for the aluminum heat spreaders). We either have an epoxy legend to burn out or we burn the solder mask to expose the copper ground plane underneath. Laser is a much
Electronics Forum | Mon Jan 30 19:27:50 EST 2017 | jgo
Hi all, I'm wondering how does one decide to use flux dipping or solder printing when it comes to be attaching CSPs onto the board? Solder printing has an advantage in that there will be a higher throughput on the mounter as there is no flux dippin
Electronics Forum | Wed Feb 01 02:39:16 EST 2017 | jgo
80 micrometres (0.08mm)
Electronics Forum | Tue Jan 31 19:34:11 EST 2017 | jgo
I have solder bumps diameters @ 80um, the board pad size @ 100um. Can this size be printed? How about dispensing?
Electronics Forum | Tue Jan 31 09:10:04 EST 2017 | Rob
Hi Joshua, We've done both, but a lot depends on what soloution your machine vendor has, and how good it is. Can you add it into your machine acceptance criteria? Rob.
Electronics Forum | Wed Feb 01 02:21:26 EST 2017 | rob
80 micrometres (0.08mm) or 80 mil (2mm)? Smallest I've seen reliably printed is around 0.2mm x 0.4mm (01005 pad) and 0.2mm x 0.2mm CSP pad, not seen anything dispensed below 0.35ish, but we are not cutting edge.
Electronics Forum | Tue Jan 31 09:41:06 EST 2017 | emeto
If there is no specific quality reason, stay with paste. More processes you add, more points of failure. They don't need a lot of paste to get attached to the board. The ones I used were 8mil round apertures, so I did cut 1:1 on a 3 mil coated stenci
Electronics Forum | Wed Feb 01 11:33:37 EST 2017 | emeto
Joshua, 100um is 4mil aperture. You should ask several stencil houses about the possibility to print that small amount of paste(type 6 paste is available now with very small solder spheres 5-15um diameter). Even applying small amount(thin layer of f
Electronics Forum | Wed Feb 01 03:17:10 EST 2017 | rob
Ok, that's small - I think you may need a special semi-conductor printer for this - positional accuracy on a "normal" SMT printer is no more than 20 micrometres from memory. In my semiconductror fab days we were printing with a positional accuracy
