ee:pcbfoametching
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ee:pcbfoametching [2021/10/04 18:02] 21960@students.hsrw |
ee:pcbfoametching [2022/02/16 10:04] 21960@students.hsrw |
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| ===== 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 (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: |
| - | + | - Create PCB mask for UV exposure. | |
| - | The technique which is covered here employs a chemical process to create PCBs. To put it simply it is a four step procedure: | + | - expose PCB to UV light while protecting certain areas with a mask |
| - | - prepare development and etching solutions | + | - develop PCB schematic using sodium hydroxide |
| - | - expose board to uv light while protecting certain areas with a mask | + | - etch PCB schematic using iron chloride |
| - | - develop board using sodium hydroxide | + | - clean PCB of residue using alcohol wipes |
| - | - etch board using sodium persulfate | + | |
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| - | The industry also these principle steps for mass production of PCBs. | + | |
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| * lab coat | * lab coat | ||
| * gloves | * gloves | ||
| + | * | ||
| ===== Procedure ===== | ===== 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 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). | ||
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| ==== Safety instructions ==== | ==== Safety instructions ==== | ||
ee/pcbfoametching.txt · Last modified: 2022/02/16 18:43 by 21960@students.hsrw
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