8. Electronics Production
Group assignment:
Characterize the design rules for your in-house PCB production process: document feeds, speeds, plunge rate, depth of cut (traces and outline) and tooling. Document the workflow for sending a PCB to a board house Document your work to the group work page and reflect on your individual page what you learned
Roland SRM-20
We usually used two types of endmill. We use the 1/64” end mill for cutting out the traces. The 1/32” end mill is used for cutting out the borders.
Preparing the Copper Board for Milling
Our lab has been using these sacrificial underlay over3 years. We decided to changed the underlay.
We removed the old underlay. Cleaned the underlay bed.
We start by preparing the copper board for milling. We collect all the required materials.
Place you copper board on the sticky side of the tape and make sure it is flat witout wrinkes in the middle.
The placed the pcb on the SRM bed and press gently.
MODS for SRM-20
Make sure you are using the correct port. Press the button to turn the machine ON
First, download the two linetest image files. These files help test the accuracy of your bits and machine by milling thin lines (0.001” to 0.02”), which is useful for determining the trace width of your circuit.
When you land on Mods page right click on red and blue icon, Click on Program.
Click on open program
Click on SRM 2D mill
You can either select the PNG file or the SVG file for the as SRM 20 support both the file formats >select 1/64 for milling the traces > Click calaculate and this generates a path for the milling.
This might take times as per you design. After generating the path, turn on the 4 and click on calculate to download your files.
Next we select 1/32 for milling the boarders > Click calaculate and this generates a path for the milling.
We followed the same procedure as above to download the rlm files
!!! note Setting for the 1/64 endmill
- Cut depth -0.004 in
- Offsetnumber-4
- Offsetstepover-0.5
- Cut speed- 4mm/s
- direction-climb
!!! note Setting for the 1/32 endmill
- Cut depth -0.024 in
- Offsetnumber-1
- Cut speed- 4mm/s
- direction-climb
Note
- 1/64 endmill -
- 1/32 endmill -
Milling
Use the allenkey to loosen and tigthen the screw
Open the VPanel for the SRM-20 and use the keys to move the spindle to your desired location. Always choose the optimal position to avoid wasting the board.
First, move the spindle to the corner of the board using the X and Y keys.
Then, set it as the home position by clicking X/Y under Set Origin Point, shown in the image below.
Secondly, Move the spindle to the center of your milling area, then slowly lower it using the Z key on the VPanel.
Note
- Switch the cursor step to x100 or x10 to lower the spindle slowly and avoid hitting the board, which could break the end mill.
Once okay with the z setting, click as shown in the image.
Roland SRM-20 is ready to mill your board.
Select the .rml files downloaded from MODS by choosing Cut > Add (ensure all other files are deleted), then open the file and click Output.
Line test result
Result
Pcb engraving using our Mr Carve
Mr Carve has four different laser sources
- Fiber laser
- Co2 Laser
- YAG laser
- UV laser
We set the different setting for the different laser source
Fistly we choose the fiber laser source and used the following parameters
Next we tired using the UV
Then we tired for the Co2, used the following the setting for the parameters
Lastly we tired using the YAG
Following are the result of the each laser source. For fiber laser source the egnraving was not that good as it engraving everything.
So our group decided to use Co2 laser source for engraving, we increase the duration of the engraving using the co2 laser. We engrave it more 45mins, however the result was not as expected.