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pcb-tips [2020/09/08 12:31] – benh | pcb-tips [2023/09/05 13:37] (current) – benh | ||
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- | Miscellaneous processing tips! | + | ==== Miscellaneous processing tips! ==== |
- | + | //So you made a few boards. | |
- | ProtoMat: | + | |
- | * Use the “ProtoLaser – ProtoMat – Double Sided – NoTHP” template | + | |
- | * Orient all your boards | + | |
- | * 4 fiducials – always. | + | |
- | * Do not forget to save before the toolpath! | + | |
- | + | ||
- | ProtoLaser: | + | |
- | * Sometimes, when placing the board, the fiducials move in the opposite direction as the board. This is a known bug! You can either: try estimating the location | + | |
- | + | ||
- | Electroplater: | + | |
- | * Clean with IPA and a TexWipe before beginning processing. | + | |
- | * If you would like to adjust the plating time, ask a PI to put you in touch with an MPI. | + | |
- | * Do not let your substrate sit in the bath (any bath) for very long after the timer runs out. | + | |
- | * If the machine throws an error on startup, it’s likely a bath needs to be topped off. Get a PI to help. | + | |
- | * After bath 3 (activator): | + | |
- | * Swipe a “reasonable” amount off with squeegee (mostly just don’t want it dripping) | + | |
- | * Dry for 20+ mins at 150F. (Higher than this can cause the ink to bake into the copper.) | + | |
- | * When rinsing after drying (after “bath 4”), scrub the copper surface | + | |
- | * Bath 5: | + | |
- | * If the current drops to zero or is very low (<10A reverse): | + | |
- | * First attempt to re-seat the PCB holder (i.e. take PCB holder out and put back onto pegs) and try again. | + | |
- | * If that doesn’t work, you may need to sand down the PCB holder’s pegs that hold the substrate to the holder (i.e. remove the board, rinse it, and then sand down the holder before restarting the acid bath step). | + | |
- | * Don’t forget to screw down the holder into place. | + | |
- | * After final bath, dry for 20+ minutes | + | |
+ | * Plating is typically avoidable by making vias with a diameter of 40 mil (1 mm). A standard 0.1” header pin can then be pushed through and soldered on both the top and bottom. | ||
+ | * Higher polygon isolation will reduce the chance of bridging to a plane during assembly (since we don’t really offer soldermask). However, it will also increase etch time because more of the substrate will be etched. " | ||
+ | * Slots! We can do them! Here are a few methods for doing them: | ||
+ | * The best method is if your CAD program allows you to generate oval holes. Then just export those with your drill file (either plated or unplated) and it should work fine. | ||
+ | * If you have square slots with a minimum dimension of at least 1mm AND they do not need plating, you can add the slots in the same layer as the board' | ||
+ | * Plated square slots have not been demonstrated yet, but my guess would be that if they have a minimum dimension of at least 1mm, then you can use a similar method to the un-plated square slots from above, but instead of generating a " | ||
+ | * Overlapping drill hits can be used as a rough approximation for a slot, and get definitely be plated, by just putting them with the other plated holes. | ||
+ | * If you're interested in optimizing your ProtoLaser experience, see the [[https:// | ||
+ | * Laser precision is dictated by many things, some (even many) of which are likely beyond your control as a user. Here is a completely-uncomplete list of some of these things (a * indicates things that you, as a user, will not be able to adjust, but get in touch if you think it's a major contributor to any issues you're seeing): | ||
+ | * Flatness of your substrate | ||
+ | * Laser power and other material-specific settings | ||
+ | * Design choices (e.g. spacing, trace widths, substrate, copper thickness, etc.) | ||
+ | * Position of the design on the substrate (left, right, center, etc.) | ||
+ | * Cleanliness of the laser lens* | ||
+ | * Level-ness of the floor* | ||
+ | * Level-ness of the sample plate* | ||
+ | * Filter cleanliness* | ||
+ | * One way to minimize systematic errors from the laser system itself is to do what might be termed a "dose test". This would involve make a very small design that has one or more features at and/or around your actual design' | ||
+ | * Another suggestion for the laser would be to define a metric for etch quality using the aforementioned test design. That way, you can quantitatively determine which parameters are doing better than others. | ||
+ | * For the laser, if you're using a substrate thinner than 5 mil (0.125mm), tabs in your design are a near-requirement! You can make them in the laser. | ||
+ | * Laser cannot do two-sided jobs with plating by itself; the plotter is required for fiducials. No idea why. | ||
+ | * You can actually make boards with more required bits than the tool magazine has slots. It will yell at you about it, but just walk through the process as normal and it will ask you to put the bits into the magazine when it needs them. | ||
+ | * The LPKF sofware handles drill hits down to 0.2mm (7.5 mil) without any adjustments, | ||
+ | [[pcb-book-of-kane|The Book of Kane]] |