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Peralta Engineering Studios

Peralta PCB Mill Specs

PCB Specifications

All PCB layouts submitted for fabrication must meet the following specifications:
  • Maximum PCB size: 9″ x 12″ (but try to minimize the size of your PCB to save material)
  • 2-layer (front and back), FR-4 laminate material, 0.059″ (59 mil) PCB thickness
  • 2 oz/ft^2 copper on each side
  • For power and ground traces, use a trace width calculator to determine the correct line width and avoid traces popping when you power up the board. Use a minimum 40 mil line width and 6 mil space between traces for all power and ground traces.
  • For signal traces, a 15 mil line width and space is recommended. Use a minimum 15 mil line width and space for all signal traces.
  • Plated-through holes (PTH) OK
  • Solder mask layers OK
  • It is recommended to put text in your soldermask or copper layers
  • Vias okay, but no blind or buried vias.
  • Minimum hole and via size: 0.5mm
  • File format: Gerber 274X
  • Drill file format: Excellon (English units)

We have also listed all of the available bits that we have on hand and some notes on what they are each used for throughout the manufacturing process.

Peralta 109 LPKF S63 Mill Bit Selection Table

Bit Type

Size (mm)

Size (in)

Size (mil)

Usage

Notes

Counter Router

1.0

0.0394

39.4

Used for cutting the board outline as well as opening holes

Board outline file

Extension: .art

2.0

0.0787

78.7

3.0

0.1181

118.1

Drill

0.5

0.0197

19.7

Used to make drill holes for through hole parts as well as mounting holes

Do your best to consolidate your design to the least amount of drill sizes need. The more drill sizes needed in a design will require more tool changes = more time needed to run you design. Using drill sizes outside of the ones available here = more time needed to run you design.

                                                                                                                                                                                     Drill File Extension: .drl

0.6

0.0236

23.6

0.7

0.0276

27.6

0.8

0.0315

31.5

0.9

0.0354

35.4

1.0

0.0394

39.4

1.2

0.0472

47.2

1.4

0.0551

55.1

1.5

0.0591

59.1

1.6

0.0630

63.0

1.8

0.0709

70.9

2.0

0.0787

78.7

3.0

0.1181

118.1

Endmill

0.2

0.0079

7.9

Used for removing copper

Only use these in a design if necessary. This process can take a long time depending on the amount of rub out required within the design.

0.8

0.0315

31.5

1.0

0.0394

39.4

2.0

0.0787

78.7

3.0

0.1181

118.1

Universal Cutter

0.1

0.004

3.9

Used for cutting traces

Top and Bottom files            

Extension: .art

0.2

0.008

7.9

 

Peralta 109 LPKF S63 Mill’s Minimum Requirements

Item

Minimums

Notes

Trace widths

Signal Traces = 15 mil, 0.015 in, 0.381 mm

Power Traces = 40 mil, 0.04 in, 1.02 mm

The 15 mil trace is the absolute minimum trace width your design should include. The current on those lines should not exceed 500mA for 0.5oz copper. For correct sizing for currents over 500 mA use a trace width calculator.

Vias

19.7 mil, 0.0197 in, 0.5 mm

Recommended values

31.5 mil, 0.0315 in, 0.8 mm (0-5amp)

Or

78.7 mil, 0.0787 in, 2 mm (5-10amp)

The default in cadence is too small, please edit it to these sizes or bigger.

Package Sizes

Two Terminal Packages

–          Resistors and Capacitors = 0805

Three Terminal Packages

–          Small-outline Transistors = SOT-223

Five and Six-Terminal Packages

–          Small-outline Transistors = SOT-23

More than six terminals

–          Pads cannot be smaller than 20 mil, 0.020 in, 0.51 mm

–          Pitch cannot be smaller than 31.5 mil, 0.0315 in,  0.80 mm

–          No QFNs or BGAs

These packages produce good results from the LPKF circuit board mill. While it still can do smaller packages, avoid them as it will most likely produce more errors. If your project requires something smaller speak with your professor or the Lab Manager.

Insulation Clearances

Thru Pin = 5 mil

SMD Pin = 5 mil

Via = 5 mil

Line/cline = 5 mil

Shape/rect = 5 mil

Set these values to 10 mil to begin with then lower if need.