Week 8: Electronics Production

group assignment: • characterize the design rules for your in-house PCB production process • submit a PCB design to a board house

Our lab’s machine for CNC milling is the Other Mill Pro.

Our lab’s CNC milling machine

Characterizing Design Rules

To characterize our machine, we used Neil’s line test and converted the PNG to a SVG using Inkscape so that it would upload in Bantam Tools.

Within the Bantam software itself, it previews a lot of what the machine’s milling tools can and can’t do. We have 1/16’‘, 1/32’‘, and 1/64’’ Flat End Mills and we have PCB engraving bits at 0.005’‘.

Capacity of the 1/16’’ Flat End Mill to mill the line test as shown in the Bantam Tools Software

Capacity of the 1/32’’ Flat End Mill to mill the line test as shown in the Bantam Tools Software

Capacity of the 1/64’’ Flat End Mill to mill the line test as shown in the Bantam Tools Software

Capacity of the above three Flat End Mills to mill the line test as shown in the Bantam Tools Software

Capacity of the PCB Engraving Bit to mill the line test as shown in the Bantam Tools Software. We also included a 1/32’’ Flat End Mill tool for this mill so it wouldn’t take forever.

Essentially, as the milling tool gets smaller, it can mill smaller and smaller lines. The PCB engraving bit could cut even smaller – it is a V-bit tool and its shape affects how it cuts. Also, it’s good practice to use the 1/16’’ flat end mill for edge cut layer so as not to cause strain on the other tools.

Overally, the standard set of 1/16’‘, 1/32’‘, and 1/64’’ Flat End Mill milling job didn’t have reliable lines until it reach at least 0.10’’ whereas the PCB Engraving bit paired with the 1/32’’ could cut a few degrees smaller.

Milled line tests

When Castor deburred and cleaned the line test prints, this showed which lines could withstand deburring.

First line test after deburring

Second line test after deburring

Submitting PCB Design to Board House

Castor and Angela both practiced with submitting our own PCB designs to a board house.

PCBWay

The basic workflow for PCBWay’s website:

• Calculate estimate cost by going to “PCB Instant Quote” page and and select specifications for PCB based on your design. Click “save to cart”
• Create Account and Verify Email (or login if account already exists)
• Attach Gerber Files and submit the file
• Wait for files to pass review process
• Make payment and process order

Inputting specifications for cost estimate

Cost estimate for board and stencil

Cost estimate for board itself. Minmum purchase of 5 boards required for this

Uploading gerber files and awaiting review before payment

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