I am bit take it back by all the comment that do not require prototype in house. if you work at mid range design, I am sure you can get away with it (not sure it would be cheap. If you add the logistic support, etc). However, if you near the leading edge, you would need to find out (a) utilise new technology that do not have standard tooling for SMT, (b) yield and MFX, including design limitation (c) inspection and test equipment requirement. Example, the flip chip on board was done eye balled for placement prior to the large area split prism pick and place machine developed. Without in house proto facility and support, most likely, you will get all of the no bid for RFQ and dead in the water. I can see why north america SMT went away. Part of reason is the design is far removed from the production in some places, which make utilisation of the leading edge technology impossible. Stuck in the mid range tech for the design, which is price sensitive product, and the north America usually lost to the low cost MFG locations, such as Asia or south. My 2 cents, I would be glad that everybody can prove me wrong.
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----- Original Message -----
From: John Goulet [mailto:[log in to unmask]]
Sent: Saturday, January 22, 2011 11:18 AM
To: [log in to unmask] <[log in to unmask]>
Subject: Re: [TN] Suppose for a moment...
I cannot see any benefits in soldering your own assemblies in-house for prototype build only.
The range of cost from quality equipment, cost to get experienced process, quality, supplier and quality engineers would be cost prohibitive. With sophisticated parts like BGAs or even PTH components where the leads are hidden by the body, inspection has to be done using Xray and all of those systems are very expesnive.
For proprietary products you can work with a contract assembler which is ISO 9001:2000 certified military instrument & parts.
Some of the key points are: Only US citizens can work on these products. The files and engineering offices and view of the PC's display cannot be viewed from out side the secured area. The parts are stored in a secured area. Even the SMT stencils are secured in a special area, as rediculous as that may seem. Obviously that may drive the cost up alittle.
The best solution is to qualify a local contract assembly company. Get an experienced engineer as a contractor to qualify a contract assembler company.
- If your products are very sophisticated you may want to choose a company that has an in-house Product Assurance Lab staffed with experts, has excellent lab equipment and has use of the factory's X-ray or laminography type X-Ray equipment. Benchmark Electronics is one of these. The factory that is closest to you may not have a qual lab. The reason is the expense of the modern equipment and high level engineers is limited to the Product Assurance Lab in Nashua NH and supports all the other facilities.
Reason for the hands on experience as cited by the tech-net members are going to be many.
- Here is are few issues just relative to components: Many of the components: switches, PTH headers and sockets have had the plating changed to become RoHS compliant. However the low temp plastic on the headers and sockets can result in the body distorting and bubbling, pins sinking down etc. The designer of the assembly checked the melting point of the PET material used in the slide switches however further down in the specification was the distortion temperature, which was 30 degrees lower. The slide switch would solder but then it wouldn't work or work for a short time. Many of the component companies have not redesigned the component bodies to change from low temp plastic to glass composite bodies. These parts can be soldered but no in a mass solder process like wave solder because if all the leads are headed at once the wire frame in the switch heats up to an unacceptable high level.
These parts have to be soldered by hand or with a very controlled selective solder with a small nozzle so that only one lead at a time is soldered by the system. The vinyl coating on Electrolytic caps comes in either 85C or 105C rating. If your going to wave solder these in the higher temperature RoHS wave then purchase the 105C caps. The extra pennies will save you dollars by preventing rework due to splitting or bubbling of the PVC sleeving.
You may want to hire a liaison engineer to be at the facility when your products are built and to record the quality and work with the contractor to improve the process or experiment with newer solder paste products etc.
John Goulet
MFG/Process Engineer
----- Original Message -----
From: "Chris Knudsen" <[log in to unmask]>
To: [log in to unmask]
Sent: Friday, January 21, 2011 10:05:52 AM
Subject: [TN] Suppose for a moment...
...you work for a small, albeit successful OEM. You produce short-run,
custom electronics. A 'production run' may be 10-50 units.
_Everything_ is a prototype.
Suppose you have this potentially irrational desire to solder all your
pcb's in-house.
Assuming:
-- Dealing with component placement and paste/screening is not an issue.
-- You tend to (sadly) avoid challenging chip packages. However, due to
availability of the more colorful components, this becomes more
difficult every year.
-- The economics are "manageable".
-- Inspection and QA are in place.
-- Damn the torpedoes.
**What type of low-volume soldering solutions would you recommend?
I've tested one name-brand, IR convection, batch, reflow-oven and found
unacceptable hot/cold spots (manufacturer will go unnamed).
**Is Vapor-phase on this scale an option?
**Typical hardware costs/concerns/safety issues?
**Required infrastructure?
Any suggestions from technet-nation would be most appreciated.
Offline responses would be fine (especially if naming names). However,
perhaps others may benefit from from your experience and recommendations.
Best regards to all,
Chris Knudsen
New England Research, Inc.
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