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SMT electronics assembly manufacturing forum.


PCB's for oven profile testing

#21319

PCB's for oven profile testing | 26 August, 2002

I want to ascertain the oven profile required for through hole connectors with solder pre-forms. I need to get double sided PCB�s made for that purpose. What is the best way to get these PCB�s made to simulate real world conditions?. Should I leave all of the copper on both sides? Should I drill extra holes? The sole intention of the experiment is to ascertain the best oven profiles for these connectors and the connectors will be the only thing on a 4�x4� PCB.

Also, is there such a thing as a �standard profile�?

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#21325

PCB's for oven profile testing | 26 August, 2002

Is there such a thing as a �standard profile�? => Not as such. Generally, people tailor their profiles to produce glam solder connections on their boards. Search the fine SMTnet Archives for discussion on the factors affecting solder reflow recipes.

What is the best way to get these PCB made to simulate real world conditions? => Have them fabricated to represent the end-use [real world] boards.

Should I leave all of the copper on both sides? => Starting to loose connection, meep, mmep, unsure � unsure, unsure of what yer talking about.

Should I drill extra holes? => See above. Probably not, unless you have a GOOD reason for drilling the extra holes. The holes will probably try to steal your solder from the preforms. So, what is the purpose of these extra holes?

Comments are: * Preforms are very expensive. Solder-houses charge NRE for every single perform they make, regardless if they have made the item six bazillion time previously or not. In fact, the designs that they keep doing over and over are the designs that they like the BEST!!! * Preforms present growth experiences in determining proper handling methods during pre-soldering. * In-line with the previous comment, consider pasting these connectors, rather than using performs. Search the fine SMTnet Archives for commentary on pin and paste, paste in hole, etc. * 4�x4� PCB involve a lot of handling. Consider paneling them-up into a standard panel size. * Given that the connectors are PTH and that they are the only components on the board, consider wave soldering the connectors to the board. * I sense that you are not telling us something. Do you want to come clean?

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#21347

PCB's for oven profile testing | 28 August, 2002

This looks like it may be a good application for an Air-Vac or Wenesco type solder station. It is a solder pot that has a small motor to pump solder up through a chimney. You can put different nozzles on the top of the chimney, so you only apply solder to a small area, such as the pins of your connector.

I've mostly used them for rework where we needed to remove a large thru hole connector or IC, but they can be used to do the initial soldering of the components.

Advantages - You can get a nozzle the exact size you need, lots of standard sizes are available, custom sizes are easy to make.

You only apply flux and solder to the area that needs it, so you don't have to run a board through a full wave solder machine. Also, you do not need adhesive for the other parts on that side.

These machines don't take up much space, I've seen an Air-Vac machine on a cart that was moved to the line that needed it.

Disadvantages- Depending on the flux you use, you may have some cleaning to do afterwards.

You need an operator with some mechanical aptitude and soldering knowledge to set up the right nozzle, adjust the board holder, etc. They are easy to operate once it's ready, but many operators are clueless when it comes to setting it up.

It adds another step to the process, and can't be done while the board is on the conveyor.

Mike F

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