GCT is expanding the range of applications for its diamond-coated tools in PCB processing with a conductive variant. Until now, the diamond coating, which is known for its significantly increased tool stability, did not permit contact machining - the coating produced using the hot filament CVD process was not conductive.
Johannes Meschenmoser, Technical Sales, GCTInthe past, the coated tools from Weingarten near Ravensburg were primarily chosen for applications where other than the usual PCB materials had to be drilled or milled (see also PLUS 11/2019 p. 1760-1763),preciselybecause of their significantly longer service life compared to uncoated carbide tools. However, the possible applications were limited to cases where conductivity was not required.
GCT has now found a way for diamond-coated tools to remain electrically conductive, making the benefits of diamond-coated tools available for the highly efficient processing of PCBs and other base materials. GCT does not currently provide any information on how the conductivity of the diamond coating is achieved. However, the engineers from Weingarten were able to prove in test series that the nanocrystalline diamond coating has the same properties in conductive and non-conductive versions.
This means that in future, the significant advantage of multiple tool service lives will be available to all users who were previously unable to benefit from this because the tool must be electrically conductive during machining. This primarily concerns contact drilling.
"Contact drilling will always be necessary if you want to produce precise deep holes or deep milling," says Johannes Meschenmoser, responsible for technical sales at GCT. This is the case when holes in the PCB only need to be drilled to a certain depth (blind holes). To do this, the surface of the drill bit and the tool must be electrically conductive. When the surface is touched, there is an electrical contact between the drill and the workpiece, and drilling can now be carried out from this contact point in a precisely defined manner.
The possibility of contact closure can also be used in such a way that the inner layer to be drilled represents the contact surface for multilayers and can therefore be drilled exactly up to it. Meschenmoser: "This opens up several possibilities for high-precision depth machining using contact drilling and contact milling."
The electrical conductivity of the tool can also be used to control breakage - provided that conductive materials are machined throughout. "The new electrically conductive diamond coating is available for almost all of our tools," says Sales Manager Oliver Neuschel.
