Home-brew PCBs using chemicals is worth pursuing for me as I want to spend less on CNC milling bits. It can give better definition and consistency of trace widths/pads. Time will tell.
Printing the circuit
1. Design layouts for single/double-sided printing.
2. Using soft gloves remove printing material (tracing paper) from package and load into printer.
3. Print using laser printer.
4. Allow Print to dry.
5. Still wearing gloves, inspect print and flatten if necessary. (flat, heavy weights, e.g. books)
6. Still wearing gloves, trim print to size and test fit to copper clad board.
7. Store print in secure, dust free area.
PCB prep
1. Still wearing gloves.
2. Using print from previous step, trim the PCB to size.
3. Load PCB into CNC.
4. Check PCB drill file and organize correct drill sizes.
5. CNC Drill all holes.
6. Using sharpie pen, coat each hole, both sides to provide etch resist at the hole/PCB boundary where the copper has been exposed.
PCB UV Exposure
1. Still wearing gloves.
2. Prepare print, sellotape and a scalpel.
3. Remove Photo resist protective covering.
4. Fit print to one or both sides of the PCB, ensuring good alignment.
5. Load into PCB Exposure box
6. Expose for predetermined time.
PCB Development
1. Change gloves to chemical resistant type. (Rubber)
2. Remove exposed board from Exposure unit.
3. Transfer immediately to developer solution.
4. Observe development until completed. (timing to be added with experience)
5. Wash with plenty of water.
6. Dry with lint-free cloth.
PCB Etching (method A)
1. Still wearing rubber gloves.
2. Prepare water bath to 50 degrees Celsius.
3. Put Ferric Chloride tray into water bath and allow the solution to rise to working temperature.
4. Inspect the PCB for any stray fibers or fingerprints.
5. Submerge PCB directly into Ferric Chloride solution.
6. Observe copper being etched and record time for repeat process.
My initial rough procedure is as follows:
Tools
PC with PCB design software
Laser printer with optimum resolution of 1200 dpi or better
Sharpie (fine tip)
Scalpel and replacement blades
PCB Cutter (guillotine)
Dry work gloves (lint free, tight fitting)
Wet work gloves (chemical resistant)
Eye protection (for chemical work)
Plastic sheeting (to protect your work surfaces during chemical processes)
Spill cleanup material (sacrificial material and a spare plastic bucket)
Tongs (for handling PCBs while in chemicals)
1" Paintbrush
Seal-able plastic containers (to hold working chemical solutions)
Deep tray for water bath
UV Exposure box
Countdown Timer
Chemical trays (Developer and Ferric Chloride)
Water bath (bucket is best if you don't have a non-metallic sink nearby)
PCB Guillotine
Laminating Machine (A4)
Printing the circuit
1. Design layouts for single/double-sided printing.
2. Using soft gloves remove printing material (tracing paper) from package and load into printer.
3. Print using laser printer.
4. Allow Print to dry.
5. Still wearing gloves, inspect print and flatten if necessary. (flat, heavy weights, e.g. books)
6. Still wearing gloves, trim print to size and test fit to copper clad board.
7. Store print in secure, dust free area.
PCB prep
1. Still wearing gloves.
2. Using print from previous step, trim the PCB to size.
3. Load PCB into CNC.
4. Check PCB drill file and organize correct drill sizes.
5. CNC Drill all holes.
6. Using sharpie pen, coat each hole, both sides to provide etch resist at the hole/PCB boundary where the copper has been exposed.
PCB UV Exposure
1. Still wearing gloves.
2. Prepare print, sellotape and a scalpel.
3. Remove Photo resist protective covering.
4. Fit print to one or both sides of the PCB, ensuring good alignment.
5. Load into PCB Exposure box
6. Expose for predetermined time.
PCB Development
1. Change gloves to chemical resistant type. (Rubber)
2. Remove exposed board from Exposure unit.
3. Transfer immediately to developer solution.
4. Observe development until completed. (timing to be added with experience)
5. Wash with plenty of water.
6. Dry with lint-free cloth.
PCB Etching (method A)
1. Still wearing rubber gloves.
2. Prepare water bath to 50 degrees Celsius.
3. Put Ferric Chloride tray into water bath and allow the solution to rise to working temperature.
4. Inspect the PCB for any stray fibers or fingerprints.
5. Submerge PCB directly into Ferric Chloride solution.
6. Observe copper being etched and record time for repeat process.
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