DFM Guidelines

We review your CAD data prior to circuit board manufacturing to make certain it’s fit for fabrication.

Design for Manufacturability (DFM)

If you need a second pair of eyes to go over your design files please send to us using our technical support page, and we will run them through our front-end CAM system at no charge.

For DFM review, we except data sets in Gerber and NC drill data exports. Use our secure contact form to share files with our technical team in full non-disclosure.

Our Suggested DFM Guidelines

We understand fine design features can be difficult to avoid with today’s technological demands. However, following these guidelines can help keep costs down and allow for smother fabrication processes.

Good design practice suggests only going tight when you need to. Our design rules offer as a guideline only.

Widths and Clearances:

  • Routing traces and buses at width of 0.005-.008″ (0.125-.20 mm).

  • Keep copper clearances for trace-to-trace at 0.005-.008″ (0.125-.20 mm).

  • Copper-to-board-edge at 0.015-0.020″ (0.40-.50 mm).

  • Keep solderable component pads away from board edge, 0.20-.30″ (5.00-7.50 mm).

Holes types:

  • Vias diameters 0.010-.014″ (0.25-.35 mm) with 0.005-.008″ (0.125-.20 mm) annular ring each side.

  • Functional through-hole annular rings 0.010-.015″ (0.25-.40 mm) depending on the hole diameter.

  • Plated Slots, 0.026-.040″ (7.00-1.00 mm). A slots >0.040″ (1.00 mm) is typically routed instead of drilled.

  • Non-Functional (non-plated holes) are typically routed instead of drilled >0.250″ (6.35 mm).

Soldermask and Legend:

  • Soldermask webbing/space between component pads at 0.004-.006″ (0.10-.20 mm).

  • Soldermask swell at 0.003-.004″ (0.80-0.10 mm).

  • Silkscreen segment widths at 0.005-.008″ (0.125-.20 mm).

  • Silkscreen character height 0.040-.50″ (1.00-1.30 mm).

Adding Teardrops:

Teardrops can be added to the design to help prevent drill break-out and fill any corner angled track junctions.

Standard deviation can allow some drill wander and layer registration during manufacturing. Adding teardrops to the though-hole pads can help prevent any drill break-out. We recommend adding on fine featured designs where the annular ring are below 5 mils (.005″).

Surface mount pads and track junctions can benefit from teardrops. Solution and chemistry can get trapped in sharp corner creating etching or adhesion issues during manufacturing.

Sharp edge junctions can incur unwanted resistance creating heat and even damage the copper circuit depending on the current.

Board thickness:

  • 0.021″ (0.50 mm)

  • 0.031″ (0.80 mm)

  • 0.040″ (1.00 mm)

  • 0.062″ (1.60 mm)

  • 0.070″ (1.80 mm)

  • 0.093″(2.30 mm)

Copper weights/thickness

Cu Weight (oz)Thickness (inches)Thickness (mils)
1/4 (0.25)0.00035″0.35
1/8 (0.375)0.00053″0.53
1/2 (0.5)0.0007″0.7
1.00.00140″1.4
2.00.00280″2.8
3.0*0.00420″4.2
4.0*0.00560″5.6
6.0*0.00840″8.4
8.0*0.01120″11.2

* Considered heavy copper and may require a non-standard stackup. See our printed circuit board stackup section for more information.

Hint: As the copper increases in weight so should the copper-to-copper clearances. There is an etching factor which typically requires artwork to be swelled in order to achieve the design trace widths post etch and during layer inspection.