Find out more about PCB design, manufacturing, pricing and administration in our frequently asked questions. PCB - Drill holes
- What is your standard drilling tolerance?
Our standard drilling tolerance is +/-0.075mm. We can also accept different permutations within our tolerance span e.g. -0/+0.15mm, -0.05mm/+0.1mm etc.
- Will the size of the plated through holes in the finished PCB be the same as they are in my design?
We consider the hole sizes in your design as finished. We do a reverse calculation to find the best actual drill tool size so that plating is compensated. We normally add 0.1mm and 0.15mm plating tolerance for all via and component holes respectively. This means a via hole of size 0.3mm in your design will be drilled with a 0.4mm drill tool. The same maths applies for component holes.
- How do I know the drill size that has been defined in my design will be right for the component?
The general rule of thumb when you design your custom library parts is that if your component lead is X mm, your drill hole should be X+0.3 to 0.4mm i.e. if your component lead is 0.4mm you must provide a 0.7mm to 0.8mm drill hole.
- How do you make sure NPTH (non-plated through) holes align perfectly with other PTH holes?
To avoid any misalignment between PTH and NPTH holes we always (unless specified) drill NPTH holes at the same time as PTH holes and make sure NPTH holes never get plated.
- Can I provide overlapping holes in my design?
Instead of providing a separate layer, many designers use overlapping holes in drill layer for slot information. This is an incorrect practice and could confuse the manufacturer. Normally, overlapping drill holes are always deleted before the final design goes into production. Slot information should always be provided in a separate layer (e.g. mechanical layers).