In February this year we completely replaced the existing brushing line used for surface preparation before solder mask application. Below is a short summary of the processes involved on this line.
First the boards are subjected to an acid rinse which will remove copper oxides, followed by a fresh water rinse.
Following the rinse the boards enter the IS international double sided brushing machine. The machine contains water lubricated oscillating brushes whose job it is to create a particular topography on the copper surface to promote solder mask adhesion.
Next the boards enter an extended 2 metre long, high pressure wash chamber that removes all loose particles. De-ionised water is used for this rinsing to prevent ionic contamination beneath the solder mask.
The boards then pass through squeegee rollers to remove any excess water prior to entering the drying chambers.
Drying is done by means of filtered air that is heated and forcefully blown onto the boards in a 1,5 metre drying module, before entering the cooling module which will cool the boards off again prior to the application of solder mask.
Upgrade to Multilayer equipment at TraX
With the increasing levels of technology on multi layers it has become even more difficult to achieve good inner layer registration, Trax has invested in a IPM 60 Inner -Layer punching machine manufactured by Piergiacomi Robotics in Italy to optimise the accuracy of inner layer registration on 6,8 and ten layer boards.
The purpose of the machine is to punch reference holes, after the etching process on the inner layers of a multilayer circuit board. These reference holes are then used on the new welding machine to reference the inner layers to one another prior to welding.
Doing this after etching is more accurate, as the machine compensates for dimensional changes of the inner layers, and optimises the best position for punching the tooling holes required for layer to layer registration during the multi layer welding process.
To do this the machine uses a visual system to pick up targets etched on the inner layers. Vacuum cups then hold the inner layer in place whilst highly accurate stepper motors optimise the position of the inner layer prior to pneumatic punching of the tooling holes.
Innerlayer Welding Machine
The matching AMM20 multi layer welding machine also manufactured by Piergiacomi Robotics of Italy completes the upgrade to the multi layer registration system.
The purpose of inner layer welding is to prevent the registered inner layers from moving during the laying up process of the multi layer stack.
The process is as follows: The inner layers to be welded are placed onto registration pins on the sliding table using the tooling holes punched by the post etch punch. Once all the inner layers have been layed up, the sliding table slides into the machine where the inner layer book (inner layers & pre-preg) is spot welded on two sides by heated bits using variable pressure dependant on the number on inner layers being welded.