|Ask the Experts|
April 2, 2007
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.
|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.
Regional Sales Manager
OK International Inc.
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.
Vice President Asia
Nordson Advanced Technologies
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.
Circuit Technology Center
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