When is it Time to Shift from Hand to Wave Soldering?

Board Talk is presented by Phil Zarrow and Jim Hall of ITM Consulting. Process Troubleshooting, Failure Analysis, Process Audits, Process Set-up CEM Selection/Qualification, SMT Training/Seminars, Legal Disputes

Phil Zarrow With over 35 years experience in PCB assembly, Phil is one of the leading experts in SMT process failure analysis. He has vast experience in SMT equipment, materials and processes. Jim Hall A Lean Six-Sigma Master Blackbelt, Jim has a wealth of knowledge in soldering, thermal technology, equipment and process basics. He is a pioneer in the science of reflow.

Transcript

Phil
Welcome to Board Talk. This is Jim Hall and Phil Zarrow of ITM Consulting, coming to you today from high atop Mount Realto in the White Trash Mountains of New Hampshire, to bring you Board Talk

I believe we have a through-hole related question.

Jim
This comes from V.N. "We assemble simple through-hole circuit boards. What are the main factors to consider when shifting from hand soldering to wave soldering, and what factors should be used to justify continuing to hand solder versus switching to wave solder?

Phil
Well, the first is: What's your budget? Are you ready to buy some equipment?

Jim
I think volume is typically the dominant factor that should be considered when changing from hand soldering to wave soldering. Obviously, with wave soldering you're going to have to buy a machine and set it up and maintain it.

You have a lot of fixed cost, so you have to be able to amortize those cost over the savings in manual labor, so that's the foundation of your decision.

Phil
Anytime you have a manual operation, which is what hand soldering is, there's an introduction of variable, and a lot of that can be people.

So even assuming you have a very well trained IPC certified tech, the fact is with hand soldering, there's great variation.

Jim
Bad hair days.

Phil
One of the goals of automating is to have more consistent, repeatable results. Even with a machine, there's operator dependency in terms that it's set up right, that correct levels are maintained. So it's not like you're free and clear, but it is a more consistent, repeatable process.

Depending upon the pin count and the other characteristics of the board, you may consider going to selective soldering, as opposed to going full bore wave. Selective wave has received a lot of attention and acceptance in the last few years. It does depend how many through-hole pins you actually are soldering.

Jim
Selective soldering may not be the best solution for large volumes of through-hole joints. Nothing is going to come close to a wave soldering machine for speed and cost per joint.

But selective soldering allows you to get down to controlling the process at the single pin level. It has a lot of advantages.

If you're coming from strictly hand soldering, some fundamental things you're going to have to consider including:

• trimming of your leads before you go into the wave soldering machine
• your lead-to-hole ratios to get a proper hole fill by capillary action
• the orientation of the multi-pin connectors

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