Electronics Forum | Mon May 28 04:29:16 EDT 2001 | hello
we met the same problem with audit, and i make a tooling log for each stencil and in tooling log , set up some criteria for checking such as tension , mechanical damage, printing result ect. The stencil will be checked periodicly by process engineer,
Electronics Forum | Thu Jun 07 01:22:41 EDT 2018 | buckcho
Hello, the colleagues are all right. What I did in addition to show customers and quality that we either need or dont need a stencil: 1. Made a procedure - in there i defined 50 000 cycles and then the stencil has to be checked by me. In the checks
Electronics Forum | Fri May 21 15:50:41 EDT 1999 | John Thorup
We are running a number of boards with 8-10 25 mil PQFPs on board. Our process is mature with at least 3 years experiance and statistically few opens on the QFPs. Our beloved purchasing department has chased the almighty $ and changed FAB vendors
Electronics Forum | Thu Mar 29 01:22:57 EST 2001 | chinaman
Hello everybody, Two questions came up during an audit (old topics once more): 1. we are not checking the solder paste volume/pad height after printing - others are using an AOI, but is it really necessary? We just do visual inspection randomly. We
Electronics Forum | Wed Dec 18 01:37:39 EST 2002 | Steve
I dont know what kind of screener you use but my 1st impression is that the board and stencil are separating too fast,the paste doesn't have enough surface tension to stay on the board, you're tearing the paste off the board. If you can, slow down th
Electronics Forum | Fri Jul 21 01:50:04 EDT 2023 | auriga2001
The purpose is explained in the program 'help' - 'contents' menu. Due to viscosity and adhesion of different fluxes, paste may stick to the stencil more than the board. Using steps allows the surface tension and gravity to pull the paste down; rather
Electronics Forum | Tue Mar 16 20:17:13 EST 1999 | Chris G.
| Are stencils universal from one printer to another? We are looking into the possibility of going from Solderprint 1414 manual printer to a more automated printer. We are also considering bringing some boards we currently outsource in house. I w
Electronics Forum | Thu Jul 20 05:04:30 EDT 2006 | bing007
We had a similar problem with gold contact pads. Cleanliness is paramount. If you are using foil tensioning system, wash the foil in a stencil wash before use as the cardboard cassettes may be contaminated. Be very careful when loading into a frame f
Electronics Forum | Mon Apr 21 16:39:50 EDT 2003 | k_h
You might try reducing your solder paste volume. To much solder paste gives the part a pool to float in, nullifying the positive effect of surface tension. I use an aperture on stencil for the heat sink which is 5mils reduced on each side and a 25mil
Electronics Forum | Tue Jan 28 12:45:35 EST 2020 | emeto
Phil, I had over 2k stencils VG and 5-6 frames and about 150changeovers per week. Frames get beaten up with time, hoses inside blow, aluminum tensioners change tension, start having nicks, springs inside wear as well. At some point you have to deal m
