Lead Free PCB Assembly
We are currently manufacturing RoHS compliant/lead free products and are actively working with our customers to convert BOMs of existing non-compliant products.
We also have a number of customers operating in Military and other market sectors that are exempt and therefore offer both lead free and standard leaded manufacturing processes in parallel.
SMT assembly
Our continued investment in state of the art pick and place machines and reflow ovens has stood us in good stead. For MRP the change over to run a lead free PCB is as simple as changing solder paste in the DEK screen printer and selecting a suitable reflow profile for the ovens.
One aspect of lead free manufacturing we have noticed is that because lead free paste doesn't flow quite as freely as leaded pastes, surface mount devices tend not to self align during reflow. As a consequence the placement accuracy of the AX has proved invaluable. When manufacturing lead free PCBs, manufacturers with lower spec or older machines, risk facing a significant rise in manufacturing defects when they transfer to lead free production.
Conventional Assembly
It isn't practical to run both leaded and un–leaded process with a single wave solder machine because of contamination of the solder pot and the alarming fact that unleaded alloys eat through stainless steel solder pots - with potentially disastrous consequences (see photo).
Because of this we have purchased a second Blundell Dual Wave Solder Machine and have one dedicated to lead free manufacturing and one dedicated to leaded manufacturing processes
Inspection
There are a number of visual differences between leaded and un-leaded solder joints. IPC A 610 has been up issued to account for this.
One benefit we have found is that because the solder joint tends to be less shiny the capability of our AOI systems to successfully inspect solder joints is greatly improved.
Further Information
Please feel free to contact our Production Engineering team for any further information, we will be happy to offer any advise or assistance with problems that you might be experiencing.
Email: engineering@mrpplc.co.uk
Alternatively the following links provide useful information:
www.aimsolder.com
www.leadfree.com