pcb-tips

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pcb-tips [2022/06/25 14:48]
benh
pcb-tips [2022/07/15 16:02]
benh
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 ==== Miscellaneous processing tips! ==== ==== Miscellaneous processing tips! ====
-//So you made a few boards. Or not! Either way, this is a running list of tips and tricks for users - things to do and things to avoid. We make no guarantee with any of these, but we have found that they'​ve helped us in some way.//\\+//So you made a few boards. Or not! Either way, this is a running list of tips and tricks for users - things to do and things to avoid, in absolutely no order whatsoever other than the order in which we discovered them. This is basically the Institutional Knowledge of the LPKF equipment at The Hive. We make no guarantee with any of these, but we have found that they'​ve helped us in some way. //\\
  
   * 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. ​   * 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. "​Isolataion"​ is usually a setting that you can edit per specific polygon; 10 mil is the default often, but 24 or 32 mil (or more, though the benefits decrease) will reduce the risks further. ​   * 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. "​Isolataion"​ is usually a setting that you can edit per specific polygon; 10 mil is the default often, but 24 or 32 mil (or more, though the benefits decrease) will reduce the risks further. ​
-  * Slots! We can do them! There are probably ​couple of methods for doing this, but the way we've had success ​is to add the slots onto the "​BoardOutline"​ layer in the software. ​How this happens depends on your EDA (CAD) softwarebut in essenceyou either ​need to have your slot in a new gerber (which ​you can assign to "​BoardOutline"​ in the Import stepor you need to put your slots onto the layer in your EDA that spits out your Board Outline gerber file (in Eaglethis layer is called ​"Dimensions"​). ​Unfortunatelywe haven'​t found good way to do plated slots because in the above method, the slot is made //​after// ​the etching is done (and therefore after the plating would be done)An alternative ​in this case would be to design your slot as overlapping ​drill hits which are done prior to plating.+  * 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'​s outline in your CAD software such that they get plotted ​onto the Gerber that gets assigned to the "​BoardOutline"​ layer in the LPKF CircuitPro ​software. (You can also just put the slots onto a completely different layer in your CAD programgenerate an additional Gerber for that layer, and then in the LPKF softwareimport it onto either ​the "​BoardOutline"​ layer or onto its own layer.) Once in the LPKF software, if your slot are on the "​BoardOutline"​ layer, select the outline of all slots that are currently on the BoardOutline layer and move them to a new layer that you create in the "​Layers"​ pane (making sure that the "​BoardOutline" ​layer is selectable has helped us to select the path in question, and then right-click on one of them to reach the "​Assign to layer..."​ submenu). Once that's done, and you're ready to generate ​your toolpath ​(save first!)generate the entire toolpath as you would normally first, and then go back into the toolpath generation window. Deselect everything but the "​Contour Routing"​ step. Click "Show details"​ under that step. Select the layer you have the slots on as the "​Source",​ the "1mm contour router"​ as the tool, "No Gaps" for the number/​style of breakout tabs, uncheck "​Replace existing toolpath",​ and check "​Inside"​ (rather than "Outside"​). ​Note that sometimes changing one of these resets the othersso double check these settings prior to pressing "​Start"​ to generate the additional toolpath. 
 +    * Plated square slots have not been demonstrated yet, but my guess would be that if they have 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 "​Contour Routing"​ toolpath, you'd generate a "​Drills"​ toolpath with the new "​Slots"​ layer as the source fileNote that in this situation, the slot would have to be converted ​to a polygon first (right-click and select "​Convert to polygon"​ if it's not already one). YMMV here. 
 +    * 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://​gtvault.sharepoint.com/:​b:/​s/​HiveMakerspace/​EZGQyfhrC0BItpbSxd_rjRQBzDyNWUubu-RCuJr6a3OI9A?​e=8kXjaA|LPKF ProtoLaser Optimization]] document for more information.   * If you're interested in optimizing your ProtoLaser experience, see the [[https://​gtvault.sharepoint.com/:​b:/​s/​HiveMakerspace/​EZGQyfhrC0BItpbSxd_rjRQBzDyNWUubu-RCuJr6a3OI9A?​e=8kXjaA|LPKF ProtoLaser Optimization]] document for more information.
   * 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):   * 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):
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   * 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.   * 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.   * 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.
  
 [[pcb-book-of-kane|The Book of Kane]] [[pcb-book-of-kane|The Book of Kane]]
  • pcb-tips.txt
  • Last modified: 2022/07/15 16:02
  • by benh