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WORK IN PROGRESS
This instruction has been written for a supervised session performed in a chemical lab. Be careful when applying to a different environment.
This instruction is about producing printed circuit boards (PCB) from prepared board schematics to component placement. The technique of PCB manufacturing employed in this lab is that of chemical etching. To put it simply it is a five step procedure:
Here is a list of supplies you probably need:
Optimally this process is executed in a chemistry lab. This is the list of needed tools:
-The PCB design and layout should be completed by students and comply with both ERC and DRC respectively. -Place ground planes on both top and bottom of PCB design (use polygon feature in eagle) to limit the amount of etching required. -Select top layer of PCB and show only tracks, ground planes, Via's and Pad's and selected marking's to be shown on PCB, note anything that is shown will be etched on to the PCB. -Save using Print to PDF ensuring the color is black, size is A4, removing attributes from the bottom of page and saving with a recognizable file name i,e PCB_top. -Select Bottom layer of PCB and show only tracks, ground planes, Via's and Pad's and selected marking's to be shown on PCB, note anything that is shown will be etched on to the PCB. -Save using Print to PDF ensuring the color is black, size is A4, removing attributes from the bottom of page, SELECT THE MIRROR FUNCTION and saving with a recognizable file name i,e PCB_Bottom. -At least one side of PCB mask must be mirrored due to the geometric nature of applying the mask. -Print both sides of PCB design on the top and bottom of an A4 paper. To do this print one side of PCB design on A4 sheet of paper, than place printed sheet of paper back in the printer's paper tray, ink side up with the already printed PCB design at the bottom of the paper tray. -Check to see if design is correctly aligned, To do this fold paper in half and check for correct pad and via locations. -If all is correct than repeat printing process with projector paper. -cut projector paper and align PCB schematic on top of each other ensuring the inked sides of the sheets are inside together, and secure in place with sticky tape ( Pro tip cut sheet off center, for easier sticky tape application).
The following substances will be used:
Make yourself familiar with safety precautions for these substances and read the safety data sheets for them.
As stated in the beginning the following steps are normally performed in a proper lab after special security instructions and under supervision.
Put on your safety equipment. This includes glasses, lab coat and gloves. Make yourself familiar with the tools.
Fig. 4: Remove protection foil
Fig. 5: UV exposure device
Fig. 6: Board under plate
Fig. 7: Check vacuum