The correct drilling of the PCB is vital to ensure the successful later plating and the component hole to solder pad registration. A mistake at the drilling stage can have calamitous ramifications later in the process.
The drilling specification is compiled from the front end data and placed on the central database for retrieval by any one of our CNC drilling machines. This data determines the size of the hole and where it will be drilled on the PCB. Additional holes are then added to the drill data to provide tooling pin and target registration points. These will be used later in the PCB manufacturing process to align the Printed Circuit Board artworks and act as a datum for final profile registration.
Cleveland Circuits uses high precision auto-loading CNC drilling equipment with high speed spindles to drill these holes accurately and with precise repeatability. There will be a wide variety of hole sizes in a PCB design and these typically range from 0.2mm up to 6.5mm.
Drill tools have a life cycle of approximately 3,000 hits (holes drilled). The drilling equipment will automatically change the tool and we set ours to replace the tool once the hit count has been reached regardless of the tip wear. This ensures premium hole quality is maintained at all times.
During drilling the effective removal of swarf from holes using powerful vacuum extraction ensures clean unobstructed holes that will become barrels in the later plating process.
Once the first Printed Circuit Board panel in the batch has been drilled it is subject to alignment confirmation with a photo-plot of the original drill positions to verify positional accuracy, diameter and hole count. When this is verified the batch quantity is run and passed on to the next department for processing.
Glossary
CNC - Computer Numeric Control.
Hits - Holes drilled.
Barrels - A conductive tube filling the drilled hole connecting layers of the PCB.
Photo-plot - A high resolution 1-1 scale image of the PCB design and hole layout.