How to produce a PCB, safely

• PCBs are manufactured using CNC machining or chemical etching
  • CNC machining mills away copper using a CNC router and design software
  • chemical etching uses UV light, photo-resist, and chemicals to remove copper
    • CNC machining is safer and less wasteful, but slower
    • chemical etching is faster and cheaper, but uses hazardous chemicals
• PCB design involves placing components, creating tracks and pads, and using design software
• PCB amendment involves updating components, modifying tracks, and repositioning pads
• PCBs are used for space-saving, reliable connections, ease of repair, and professional appearance

There are two main ways to manufacture printed circuit boards (PCBs):

1. CNC machining
2. Chemical etching

Using a CNC milling machine to mill away the unwanted copper to create a circuit board

Tools required: Computer with PCB design software, CNC router and copper-clad board

Process:

1. Design the circuit using PCB design software
2. Export the design to the CNC machine.
3. Secure copper-clad board to the CNC bed.
4. Run the CNC program to mill away unwanted copper.
5. Drill component holes, if needed.
6. Clean the board to remove debris.
   • Pros: safer, no chemicals, less waste
   • Cons: slower for complex designs

Using a chemical method to remove the unwanted copper to create a circuit board.

Tools required: UV light box, photo-resist board, developer solution and an etching tank.

Process:

1. Design the circuit using PCB design software. Print the design onto a transparency/acetate sheet. This is called the PCB artwork
2. Prepare the photo-resist board by peeling off the protective film. Place the transparency on the photo-resist board. Expose to UV light in a light box (approx 3 minutes)
3. Develop the board in Sodium Hydroxide solution (about 10 seconds). Rinse the board with clean water
4. Place in a heated etching tank of Ferric Chloride (15-45 minutes). This will remove unwanted copper. Remove and rinse when etching is complete.
5. Drill component holes with a PCB drill
   • Pros: faster for multiple boards, cheaper
   • Cons: uses harsh chemicals, more environmental concerns

• space-saving compared to just using components soldered using loose wires
• easier to repair - just swap components
• more reliable connections
• professional appearance

When working with printed circuit boards (PCBs) or breadboards, it's crucial to stay safe. Here are the key hazards to watch out for:

1. short circuits:

   • double-check connections before powering on
   • use insulated tools to avoid accidental shorts
   • keep metal objects (like paperclips) away from live circuits

2. component damage:

   • handle components gently, especially integrated circuits (IC)
   • be aware of static electricity
   • check polarity of capacitors and diodes before inserting

3. burns:

   • let soldering irons cool completely before storing
   • be careful with hot components after extended use

4. chemical exposure (for pcb etching):

   • wear gloves and eye protection
   • work in a well-ventilated area
   • dispose of chemicals properly

Tidy workspace = safer workspace.

Keep things organised and you'll reduce risks!