ee:pcbetching
Differences
This shows you the differences between two versions of the page.
| Both sides previous revision Previous revision Next revision | Previous revision | ||
|
ee:pcbetching [2019/01/11 13:32] FKR@staff.hsrw |
ee:pcbetching [2021/03/08 13:39] (current) |
||
|---|---|---|---|
| Line 1: | Line 1: | ||
| - | ===== Etching PCBs ===== | + | ====== Etching PCBs ====== |
| - | ==== Disclaimer ==== | + | ===== Disclaimer ===== |
| This instruction has been written for a supervised session performed in a chemical lab. Be careful when applying to a different environment. | This instruction has been written for a supervised session performed in a chemical lab. Be careful when applying to a different environment. | ||
| - | ==== Introduction ==== | + | ===== Introduction ===== |
| This instruction is about producing printed circuit boards (PCBs) from already prepared designs. There are two major techniques for PCB manufacturing. For prototyping purposes it is popular to use a special milling machine for PCBs. The faculty uses a LPKF ProtoMat S62 in its [[ee:electricalworkshop|electrical workshop]]. EAGLE board designs are exported to gerber and excellon files and after making some adjustments in a CAM tool like CircuitCAM designs can be used for milling out copper-clad boards. The machine isolates all traces on the board and drills holes where necessary. | This instruction is about producing printed circuit boards (PCBs) from already prepared designs. There are two major techniques for PCB manufacturing. For prototyping purposes it is popular to use a special milling machine for PCBs. The faculty uses a LPKF ProtoMat S62 in its [[ee:electricalworkshop|electrical workshop]]. EAGLE board designs are exported to gerber and excellon files and after making some adjustments in a CAM tool like CircuitCAM designs can be used for milling out copper-clad boards. The machine isolates all traces on the board and drills holes where necessary. | ||
| Line 16: | Line 16: | ||
| - | ==== Resources ==== | + | ===== Resources ===== |
| Here is a list of supplies you probably need: | Here is a list of supplies you probably need: | ||
| Line 50: | Line 50: | ||
| * lab coat | * lab coat | ||
| * gloves | * gloves | ||
| + | ===== Procedure ===== | ||
| ==== Masks for uv exposure ==== | ==== Masks for uv exposure ==== | ||
| The PCB design should already be finished and the artwork should be ready. If not there is a separate guide on how to [[pcbuvmasks|create masks for uv exposure]]. | The PCB design should already be finished and the artwork should be ready. If not there is a separate guide on how to [[pcbuvmasks|create masks for uv exposure]]. | ||
| Line 92: | Line 92: | ||
| - Get the transparent foils containing your PCB design. | - Get the transparent foils containing your PCB design. | ||
| - | - Go to the fume cupboard at the end of the room and apply some density spray to both foils. Make sure to apply it on the side with the printing. | + | - Apply some density spray to both foils. Make sure to apply it on the side with the printing. This step has to be executed in a well ventilated room, if available do it under a fume cupboard. |
| - | - Wait for it to dry. The black areas should be clearly darker now. | + | - Wait for the density spray to dry. The black areas should be clearly darker now. |
| - | - Use the scissors to cut out your design. Leave a big surrounding area, as you will nedd it for stapeling. | + | - Use scissors to cut out your design. Leave a big surrounding area, as you will nedd it for stapeling. |
| - Place the foils on top of each other. The sides with the printing on it have to be facing each other (the board will be in between of the foils later). | - Place the foils on top of each other. The sides with the printing on it have to be facing each other (the board will be in between of the foils later). | ||
| - Staple the foils together while trying to align them perfectly. | - Staple the foils together while trying to align them perfectly. | ||
| - Check the alignment. Misalignments will probably result in defective PCBs later. | - Check the alignment. Misalignments will probably result in defective PCBs later. | ||
| - | - Get a piece of fotensensitive base material (FR4 in this case) for exposure. It will be slightly bigger than your design so you should have no problems with that. | + | - Get a piece of fotensensitive base material (FR4 in this case) for exposure. It should only be slightly bigger than your design. If necessary cut it with a plate shear. |
| - Remove the blue protection foil (see <imgref RemoveProtectionFoil>) on both sides. | - Remove the blue protection foil (see <imgref RemoveProtectionFoil>) on both sides. | ||
| - | - Avoid exposing the unprotected plate to sunlight (all UV sources). | + | - Avoid exposing the unprotected plate to sunlight (all UV sources). Best to have a special room for this step, if not available make sure to not waste to much time. |
| - Put the copper plate between the transparent foils and put both under the glass plate of the uv exposure device (see <imgref UVExposureDevice>, <imgref BoardUnderPlate>). | - Put the copper plate between the transparent foils and put both under the glass plate of the uv exposure device (see <imgref UVExposureDevice>, <imgref BoardUnderPlate>). | ||
| - **Beware:** For your own safety avoid looking into the uv lights. The device is to be only turned on when closed! | - **Beware:** For your own safety avoid looking into the uv lights. The device is to be only turned on when closed! | ||
| - | - Turn it on and wait for the vacuum to go up to 0.3, compare to <imgref CheckVacuum>. The vacuum prevents things from moving. | + | - Turn it on and wait for the vacuum to go up (to 0.3 with our device, compare to <imgref CheckVacuum>). The vacuum prevents things from moving and presses foils and PCB together. |
| - | - Set the exposure time to two minutes and thirty seconds (the display should read 2-3-0), make sure the bottom lights are also enabled as you are making a two sided PCB and start the device by pressing the knob once. | + | - Set the exposure time to two minutes and thirty seconds (the display should read 2-3-0), make sure the bottom lights are also enabled if you are making a two sided PCB and start the device by pressing the knob once. |
| - When the time is up the lights will automatically be turned off and the vacuum will be released. | - When the time is up the lights will automatically be turned off and the vacuum will be released. | ||
| - Open the device and get out the exposed board. | - Open the device and get out the exposed board. | ||
| Line 120: | Line 120: | ||
| - Brown residues from the exposed parts of the board should start to appear after a couple of seconds. Stir until the process seems to stop and take it out immediately. Do not leave the board in for longer than 90 seconds maximum. | - Brown residues from the exposed parts of the board should start to appear after a couple of seconds. Stir until the process seems to stop and take it out immediately. Do not leave the board in for longer than 90 seconds maximum. | ||
| - Rinse the board thoroughly with (purified) water. | - Rinse the board thoroughly with (purified) water. | ||
| - | - Check the temperature of the etching solution, it should be above 40 and below 50 degrees C. | + | - Check the temperature of the etching solution, it should be above 40 and below 50 degrees C. If not, keep waiting. |
| - | - Mount the board to the grey retainer (see <imgref Holder>). To speed up the procution process mount two boards at the same time. | + | - Mount the board to the grey retainer (see <imgref Holder>). To speed up the procution process you may want to mount two boards at the same time. |
| - Submerge the board(s) in the tank. | - Submerge the board(s) in the tank. | ||
| - Wait for the etching process to complete. You may have to wait a couple of minutes before something seems to be happening but from this point it should be going quite fast and obvious. | - Wait for the etching process to complete. You may have to wait a couple of minutes before something seems to be happening but from this point it should be going quite fast and obvious. | ||
| Line 129: | Line 129: | ||
| - Shut down pump and heating. | - Shut down pump and heating. | ||
| - Use ethanol and paper tissue to remove the remaining photoresist from the board(s). Be thorough. | - Use ethanol and paper tissue to remove the remaining photoresist from the board(s). Be thorough. | ||
| - | - Let the board(s) dry. | + | - Let the board(s) dry. You can also use compressed air to speed things up. |
| - Clean the lab equipment, rinse everything with water. | - Clean the lab equipment, rinse everything with water. | ||
| - Dispose of waste properly. | - Dispose of waste properly. | ||
ee/pcbetching.1547209970.txt.gz · Last modified: 2021/03/08 13:39 (external edit)
Page Tools
