The outer and inner contours of PCBs are usually milled. This also includes cutouts, slots and slotted holes. Holes with a diameter of 6 mm or larger are also milled.
Milling always comes at no extra-charge at Multi-CB.
Please observe the following rules:
- The inner and outer contours of the circuit board should be indicated with a line width of 1µm! This prevents problems in dimensioning and measurement.
- Please avoid milling copper (durability of the circuit board, risk of injury).
- Outer corners of contours may be 90°, or rounded to your specifications.
- The inner corners of contours have at least the radius of the milling tool. The standard milling tool has a diameter of 2mm, which corresponds to a radius of 1mm.
- Recommendation: Do not allow any milling to finish flush with the scoring lines. The milling should extend beyond the scoring line ( guideline e.g. 250µm), where possible.
Design Parameters
Milling / PCB contour
| Parameter | Value |
|---|---|
| Line width | 1µm |
| Min. milling tool diameter Ø | 2.0mm (special production 0.8mm) |
| Min. radius for inner corners | 1.0mm (special production 0.4mm) |
| Min. spacing copper / milling | 200µm |
| Min. spacing solder-stop / milling | 100µm |
A milling head diameter smaller than 2 mm is possible on request, but should be avoided for reasons of efficiency. The 2mm milling cutter has the highest feed rate with high precision. The contour of Flex PCBs is laser cut.
Milling / NPTH slots
| Parameter | Value |
|---|---|
| Line width | 1µm |
| Min. milling tool diameter Ø | 0.8mm |
| Min. radius for inner corners | 0.4mm |
| Recommended layer | Dimension-Layer, z.B. EAGLE layer 20 |
| Copper exemption | 150µm |
| Note | The copper exemption must be applied to all layers. Only then is the NPTH slot clearly defined as NPTH. |
Milling / PTH slots
| Parameter | Value |
|---|---|
| Line width | 1µm |
| Min. milling tool diameter Ø | 0.6mm |
| Min. radius for inner corners | 0.3mm |
| Recommended layer | Milling (mechanical layer), e.g. EAGLE layer 46 |
| Min. annular ring | 200µm |
| Note | Requires copper connection in TOP and BOT for through-plating and to be clearly defined as a PTH slot. |
Milled-out portion for exactly rectangular parts
To hold exactly rectangular parts, the corresponding milled-out portion should also be drilled at the corners; this permits (for example) a precise framing for seven-segment display units.
Z-axis milling (level milling)
Z-axis milling, also known as depth routing or level milling, reduces the thickness on certain areas of the PCB (different height levels). This can be done inside or at the edge of the PCB.
To do this, create a new layer in your PCB design software just for Z-axis milling. Set the contour (1mil) for the milling area in this layer. Also enter the desired depth and the desired side (TOP or BOT).
The tolerance in the Z-axis is ±0.20mm.
The PCB calculator automatically calculates the price and production time for a single Z-axis depth. For different depths or for contacted Z-axis milling, please select “customized option".
Milling/scoring combination hassle-free
If the outer edge of the milling lies on the scoring line, the milling tool moves along the scored base material. This increases the risk of forming of chips.
Advice: Do not mill directly aligned with scribe lines.
We manufacture PCBs with milling and scoring on the same line. Should this result in shaving (chip) formation, a reclamation in this regard would be rejected.