PCB Slots and Cutouts: How to Specify Them Clearly
A slot drawn on silkscreen can describe a desired opening without actually defining a manufacturing operation. To receive the intended shape, provide fabrication geometry and identify its purpose. The most useful handoff shows where material must be removed, the finished dimensions and whether the wall must be plated.
Separate slots from explanatory artwork
Use the CAD tool's supported slot or mechanical-output workflow. Eurocircuits' slot guidance explains that slots may be represented in suitable drill data or a mechanical layer and warns against relying only on copper or legend artwork. A series of overlapping round holes is not a clear substitute for an explicitly defined slot.
Keep the mechanical output aligned with copper and drills. Name the file in a release note so the reviewer knows which geometry controls the opening. If there are several mechanical drawings, identify the current fabrication drawing and remove obsolete alternatives from the archive.
Record the dimensions that matter
State finished width and overall length, including the rounded ends where applicable. Identify the center position from a meaningful datum. For a connector tab, compare the slot against the component drawing and explain which fit is critical. Do not leave the reviewer to decide whether a length refers to the straight section or the complete feature.
- Mark each slot as plated or non-plated.
- Identify internal cutouts separately from the outer profile.
- State any critical tolerance on the drawing.
- Show clearance to nearby copper and mechanical hardware.
Account for the cutting geometry
An internal corner made with a rotating cutter has a radius. If a mating part requires a square corner, discuss a suitable relief or another feasible design before finalizing the enclosure. Choosing an arbitrarily tiny radius in CAD does not establish that the requested board thickness and fabrication process can produce it.
Use a feature-by-feature approval
Consider a board with two connector slots and one enclosure cutout. Label them S1, S2 and C1 on the drawing, and ask the reviewer to confirm those three features. This is more actionable than asking whether the entire file looks correct. After any change, review the resulting contour and drill overlay again, then record the accepted revision in the order.
Use the related file and ordering checklist to prepare your handoff, then request a quotation from DIYIPCB. Include special requirements with your files for review.
Technical reference: Eurocircuits: defining slots and cutouts. Supplier-specific process limits in the reference are not DIYIPCB manufacturing commitments.