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Leadfreemagazine.com
is brought to you by a consortium of leading companies
in the industry: Aqueous Technologies, BTU International, Creative
Automation, DEK, ESSEMTEC, EVS International, Kester, KIC, Kyzen, MVP, Ovation Products, Polyonics,
Practical Components, TYCO, and VJ Electronix |
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Thermal
Process
Bjorn Dahle
KIC - Embedded Designs Inc.
KIC
15950 Bernardo Center Dr. #E
Sand Diego, CA 92127
tel:858-673-6050
fax:858-763-0085
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If I Run a Lead-free Profile Can I Use the Same Profiling Equipment as for a Leaded Profile?
Probably not. First, you are going to have to make sure that the thermal couples (TC) you are using can handle the higher temperatures of a lead-free profile. The standard teflon-coated TCs are typically only rated to 260°C, while the medium-temperature TCs are rated up to 400°C. Also, you will need to determine if your profiling unit needs extra protection from the higher temperatures in the reflow oven.
Next look at the process. What does the paste manufacturer recommend for a profile — a ramp to peak or a soak profile?You need to make sure that you are following the paste manufacturers’ paste profile to get the best results. Finally, the tighter lead-free process window may require a more sophisticated process optimization software for your profiler.
When Running Lead-free Do I Need to Set Up a Separate Recipe for Each of My Production Boards or Can I Run One Generic Production Recipe for all Board Types?
In general, each production board should have its own recipe for production. You can take board families, i.e. same density/layer count/weight and run these boards on the same production recipe. This could help reduce the number of recipes that you are required to run. For example, you could have three main recipes for small, medium and large boards that could possibly run 80 percent of your product needs and then have specific recipes for those boards that require it. Please keep in mind that if you are required to provide profile or process documentation for each unique product, you may need to run a profile for each product anyway, whether you use common or separate oven recipes.
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