Ask the Experts
April 2, 2007 - Updated
July 4, 2007 - Originally Posted

Lead-free connector rework

I'm looking for process guidelines to remove a lead-free Mictor connector on a lead-free PCBA. The PCB thickness is 0.100 mils and Mictor ground pins are not protruded on bottom side. The challenge is having the sm pads and pth pins at the same time in reflow without overheating the PCB. All recommendations are welcome.

Yves Desrochers

Expert Panel Responses

There is only one method I can identify for this type of application, the pcb will require substantial bottom side heat, combined with a convection top heater with mechanical lifting capacity. The APR-5000-XLS machine has the ability to concentrate the bottom heating to a small location on the board and the tweezer convection nozzles will grab and lift this part from the board with programmable accuracy.

Edward Zamborsky
Regional Sales Manager
OK International Inc.
Ed Zamborsky is a Regional Sales & Technical Support Manager for Thermaltronics, located in New York. His position requires frequent customer visits throughout North America and the Caribbean and his position encompasses not only sales but the role of trainer and master applications engineer for all of Thermaltronics products. His expertise includes such specialties as hand soldering, convection and conduction reflow techniques, array rework, fluid dispensing equipment, and fume extraction. Ed has authored many articles and has presented many papers on topics such as; Low Volume SMT Assembly, Solder Fume Extraction, SMT Rework, BGA Rework, Lead-Free Hand Soldering, High Thermal Demand Hand Soldering, Lead Free Visual Inspection and Lead Free Array Rework.

Flextronics already has some sites equipped with a Laser Rework system from ViTechnology. This is a contact less system with extremely good heat transfer which may be able to be used for this application. If you email me I can give you some contacts within Flextronics sites in Europe and Asia.

Mark Norris
Vice President Asia
Nordson Advanced Technologies
Responsible for Nordson Advanced Technology Electronic Systems throughout Asia including China, Taiwan, Korea, Japan & SE Asia. Nordson Advanced Electronic Systems includes the world leading technology companies Asymtek Dispensing, Dage X-Ray, Dage Bond Test, March Plasma, Matrix AXI & Yestech AOI.

Excellent question. No doubt this will be a tricky rework requiring the proper approach to avoid damaging the assembly. As Ed mentions, I would suggest using a hot gas process with equipment that can be programmed with a thermal profile that will heat the entire assembly up to a pre-heat temperature from the bottom and then drive reflow temperature selectively through a nozzle.

Of course the nozzle has to be sized properly and the operator may need to improvise a tool to lift the connector out once reflow is observed. Another important consideration with this approach is potential collateral damage; precautions will need to be taken to mask off any susceptible components in the area of the rework.

Bob LePage
Sales Engineer
Circuit Technology Center
Mr. LePage has been a key member of the team at Circuit Technology Center since 1996. He has vast expertise, experience and understanding of complex circuit board rework, repair and modification operations. He is one of the most knowledgeable experts in this area across the globe.
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