Electronics Forum | Thu Jun 12 03:37:05 EDT 2008 | benefon
It is also possible to etch the barcodes directly on the PCB by using a laser. The solder resist mask is easily burned by laser and if there is copper underneath the contrast is quite good. The contrast is satisfactory even if there is no metal under
Electronics Forum | Fri Jul 11 09:37:16 EDT 2008 | realchunks
BGAs are actually easy, but proper stencil design, solder paste placement and oven profiles are a must. Especially oven profiles as this is your only indication that the inner balls have reached proper temp, since you cannot visually tell. If you g
Electronics Forum | Tue Nov 11 16:30:08 EST 2008 | naynayno
Occasionally solder mask thickness is believed to be the cause of gasketing challenges during paste printing. We currently specific IPC-SM-840 on our fab drawings but this provides no limits or guidelines on thickness. I do not want to cause an unr
Electronics Forum | Tue Dec 09 10:04:36 EST 2008 | lazzara55
SMT-ypw: Does PWB supplier start to implement PWB drying packaging? B3: YES! The fabrication of the PCB involves a series of wet processing that requires counter-measures to remove moisure. While some of the PCB processes also include bake cycles th
Electronics Forum | Tue Feb 03 03:57:37 EST 2009 | sachu_70
Hi George, I would suggest you to re-look your process parameters, especially for the pre-heat temperatures and the amount of flux deposited. The mask properties and that of your flux also play a role, but you could zero down to the root cause after
Electronics Forum | Thu Apr 15 10:44:28 EDT 2010 | dwonch
Dumb question maybe but does the board have a layer count window? Usually each layer has it's number visible in copper somewhere on the board and the shop will leave the solder mask clear of this window. If the layers were stacked incorrectly it woul
Electronics Forum | Thu Nov 10 02:04:26 EST 2011 | julien
We've got the same problem here, what we do is to apply peelable solder mask around the connectors or the exclusion zone. But be carefull! Sometimes the soldermask get inside the connectors and you can't remove it so you have to change it. Another th
Electronics Forum | Fri Jan 06 05:03:11 EST 2012 | richieoreilly
Hi All, Just wondering if anyone is placing 0201 components in volume. If so What pad layout are you using, i.e. pad size, shape and spacing. Also are you pads and fiducials solder mask defined or copper defined. Can you also let me know the rough q
Electronics Forum | Fri May 18 06:49:58 EDT 2012 | kahrpr
We us a lot of 1B31 it could be one of the most common coatings out there. We do not clean the boards and do not have an issue. I would check the solder mask compatibly. I would also see how the 3rd party company is testing the boards what criteria o
Electronics Forum | Fri Jan 24 16:54:24 EST 2014 | davef
Yeh, I worked at Wang Computer factory in a reclaimed fabric mill with wooden floors. One of the causes of grapping is flux loss. In their paper, Briggs and Laskey talk about flux loss due to spreading and suggest: * Graping is much less prevalent i
