Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Reflow Carriers

Views: 1799

SWAG

#43627

Reflow Carriers | 28 August, 2006

We are constantly messing around with easy ways to transport double sided boards through reflow. (Boards that cannot ride on the chain fingers for any number of reasons). We've got some fancy Durostone carriers that work awesome but are product specific and $$$. Has anyone out there used/designed a multi-product-carrier? I've thought about building something with a grid pattern and holes for pins to hold the board in the air. Another idea is to build a frame and stretch some fine mesh over it and hope the chance of parts being moved in reflow is low. Any ideas or products that you can share??? FYI we've been seeing that running Durostone carriers down on the mesh belt is resulting in poor reflow as we head into lead free. It seems that the board needs to be up off the mesh to provide more air flow from the lower heaters - a problem not seen as often in leaded. Could be a profile thing but it's likely the TAL window is being easily affected more than lead. Additionally, we are experiencing warpage/sag on our larger Durostone fixtures with lead free.

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CL

#43638

Reflow Carriers | 29 August, 2006

Good Morning SWAG,

We have the same situation. We have found that for the most part, bottomside components do not move from thier location durring reflow unless pressure is applied. We have had instances where the component is able to drop down into the mesh and get swiped off by a belt support. What we have done is purchased a few sheets of .015" G10 material (Glass/epoxy). We have had .250" holes drilled out on 1" grid. We use this sheet on the mesh as the carrier. The holes are to aide in airflow. We have had to modify some prifiles to account for the airflow difference but it works on almost evrything and the only modification we generally make, it to trim the sheet to be slightly larger then the PCB.

This beats having a $XXX fixture for every product and probably cost us under $100.00

Good Luck

CL

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RDR

#43641

Reflow Carriers | 29 August, 2006

Make a frame that is larger than your largest board, or make a few sizes whatever you chose. Contact Fancort about their modular universal wave fixtures and "enhance" design for reflow, you will get the point when you go look at fancorts website.

Russ

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SWAG

#43651

Reflow Carriers | 29 August, 2006

Great, thanks for the advice.

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