Electronics Forum | Tue Mar 18 09:11:14 EST 2003 | Rob C
With a standard valve and no-clean solder paste you may get a few good dots. But, repeatability will be terrible too many variable, air-pressure, board height (two post nozzle), valve time on/off, retract height, retract time, etc... A RMA paste wi
Electronics Forum | Tue Nov 28 18:10:13 EST 2000 | Michael Parker
Norman- I would be pushing to get the real world to match the ideal world, in other words get your jobsetters to do the right thing. You are looking to incur more costs to justify not having to make people do their job right. A bit of training a
Electronics Forum | Fri Feb 11 00:22:05 EST 2005 | Grant
Hi, That's what I am thinking, and we might have a dirty stencils and cannot see the problem. We are going to get a magnifier, and check it out. I did not think the stencil could bur, but I didn't want to shoot the guys down when they had an idea on
Electronics Forum | Wed Mar 30 15:15:03 EST 2005 | chunks
This is a pet peeve of mine. The paste height requirement is generally asked because the customer has no clue about screen printing, but knows to ask this question. If he did know even a little about printing, he�d ask you to assure the �volume� of
Electronics Forum | Thu May 10 16:17:59 EDT 2001 | davef
I am unaware of any industry standard for specifying apertures for SM stencils. I am aware of IPC-7525, Stencil Design Guidelines. You can obtain it from IPC [http://www.ipc.org]. Further, it seems like there is an article on stencil design ever
Electronics Forum | Thu Oct 26 08:59:56 EDT 2000 | Antonio A. Medina
Ok guys, I need help. Here's the deal. We're getting micro solder balls under discreets on the bottomside of the board. Here's my set up... MPM screener w/vacuum plate 6 mil metal screen with 90% circular (rounded) apertures 7 mil (measured) past
Electronics Forum | Thu Nov 15 09:29:29 EST 2012 | anvil1021
Maybe this piece of information will help. In China (just returned from visit) there are many factories that are using a dual temperature process using SAC305 or Sn100C and 42/58. Apparently this allows them to run their through hole parts through re
Electronics Forum | Fri Nov 02 14:46:18 EDT 2012 | ericrr
So how does this (lead free paste Sn42/Bi58) solder compare with the Sn-Ag-Cu (Tin-Silver-Copper) combination which does not flow as well (in the oven), needs higher oven temperature, (that can be adjusted by reducing the oven chain speed) and cost m
Electronics Forum | Thu Jul 23 11:39:16 EDT 1998 | Russ Miculich
Are you using a HASL board or an organic protection on the pads? This will help determine as to whether paste is necessary or just a very active/tacky flux should be used. Tight process control will also help in the reflow oven. Many users don't wan
Electronics Forum | Thu Feb 08 09:07:22 EST 2001 | Hussman
OK, without knowing the specifics, why does everyone blame the oven? Most solder balls occur around R's and C's in almost every shop I've been to. The best place to start looking is the screen printer - not the oven. Sure the oven is the last proc
