Electronics Forum: dave (Page 216 of 327)

Re: Touch up on 0603 Chips ( Ceramic caps)

Electronics Forum | Tue Feb 01 21:44:54 EST 2000 | Dave F

Ashok: A fine mess you gotten us into now!!! ;-) You have no good options. BEST OPTION: Get the customer to accept the boards "as is." Rework will only degrade the product. Agree to accept all liability related to this solder condition (which y

Re: Conformal Coating on Circuit Boards

Electronics Forum | Sat Jan 29 13:06:18 EST 2000 | Graham Naisbitt

Todd, All liquid coatings are Newtonian - they follow gravity so they do indeed run away from sharp leads and edges. Silicones are generally worse because they have very low surface energy - although this is an asset when trying to get under compone

Re: High temperature solder paste for gold plated MCMs

Electronics Forum | Thu Jan 27 14:49:53 EST 2000 | Glenn Robertson

Tuan - One of the reasons I suggested pre-tinning (aside from the negative effects of Gold on appearance and reliability) is the known slower wetting of Sn/Ag and Sn/Cu alloys as compared to Sn/Pb. If you don't have to be Lead-free, the high Lead

Re: what's your opinion

Electronics Forum | Fri Jan 28 06:01:13 EST 2000 | k.s park

HI. Mr. Dave F First of all I appreciate your advise. Here is the answer to the question you sent. I was considering the solder inspection m/c for a long time. so i bought the LSM2 last year.i thinks it was good for me. further more Last year

Re: Conversion to no-clean solder paste

Electronics Forum | Tue Jan 25 09:25:23 EST 2000 | Dave F

Kris: I can appreciate your hesitance. Done correctly with proper planting and fore thought, the change to no-clean affects every part of your operations operations from purchasing to receiving and on down the line. Two things: 1 Following with y

Re: Wave Solder Flux Weight

Electronics Forum | Tue Jan 18 08:40:42 EST 2000 | Dave F

Hey John: Chrys wrote a good description on calculating flux density a while back. Here is our version of her procedure: 4.3 Determine the amount of flux on the board. 4.3.1 Get a piece of corrugated cardboard and a weighing scale accurate to 0.01

Re: BGA voids

Electronics Forum | Mon Jan 17 21:01:21 EST 2000 | Dave F

Dennis: On your BGAs: * Never seen voids any place other than the top ... lower density stuff rises. * Our spec on voids says: 1 Voids 1a Voids in soldered balls shall be less than 20% of the diameter of the solder ball. 1b No void shall sho

Re: Mid Chip Solder Balls

Electronics Forum | Fri Jan 14 17:24:08 EST 2000 | John Thorup

Yeah, it would be kind of expensive to replace all of your stencils but it's the only real answer. Be sure that all your new and replacement stencils have a home base or home plate shape for the passives. This reduces the paste volume near the cent

Re: gold fingers over wave

Electronics Forum | Thu Jan 13 13:16:40 EST 2000 | Dave F

Tony: You have choices: * Hi Temperature Tape: Go with Wolfgang ... too tough to control. * Selective Soldering Pallets: Some like 'em some don't. A lot of your success depends on the pallet fabricator. * Screenable Temporary Solder Mask: Wol

Re: Control the solder paste

Electronics Forum | Tue Jan 11 05:46:09 EST 2000 | Wolfgang Busko

Hi Dave, that was kind of a more rhetorical question. Normally paste is used before shelflife expires and delivery time is short enough to get in no trouble. The normal situation is that you try to get your equipment running means constant use of pas


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