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How to create slotted holes in pads.

Comments

10 comments

  • Tom Mattus

    Hello All, I've accomplished making the slotted footprint etc, but when I run the DRC it gives me errors; P-P and T-P, pad to pad and track to pad. Are these to just be ignored because there are pads over pads by design as described in tutorial? 

    Thanks!

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  • Ian Mellors

    Thanks for the tutorial, I've managed to produce a design with slotted pads for my project, however my chosen pcb manufacturer can only produce plated slots from pads, not from details on the mechanical layer. 

     

    I've got round it by adding vias and getting all the tracks leading to the slotted holes on the same layer, allowing unplated slots. Not ideal but will get me going for now.

    So this is a development request I guess - can we have the ability to define a non round hole in a pad in a future release???

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  • Vishal Sapre

    Thanks for the Tutorial. 

    However, one of the simplest methods that could have been was to have a choice of DRILL SHAPE in the HOLE selection in the PAD style dialog. There is already the choice of external PAD shapes. Only that the internal drill is still only a HOLE which is by default round shaped. If a DRILL SHAPE choice was added, people could create new PADS of the desired shape and simply place these pads, instead of going through the process of creating an entirely new layer.

    This can go as a good feature request for the next version. I second the previous suggestion.

    Best Regards,

    Vishal Sapre

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  • DesignSpark PCB

    From a visual perspective 'shaped holes' would be a nice solution, but the issue is with the file format and manufacturing requirements. Drill files are for holes drilled with conventional drills, slots require to be milled. Manufacturers normally reject drill files that contain milling instructions, hence the requirement to add the details on a seperate layer.

    Pro does simplify slotted pads, however this also adds the slot information to a seperate layer for the manufacturer.

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  • Nick M

    This is a very good manual but it doesn't do the job for me - I wonder if I am missing something?

    I am making slotted holes for a Kycon power connector so I have 2 Vcc and 2 Gnd pins and some extra mechanical pins. I have followed instructions above, have mechanical layer and created a footprint for this connector.

    So first I create an SMD pad that is larger than the slot - all as per instructions on this page. This SMD pad goes via all layers (again as per instructions, presumably to provide connectivity between slotted pins and layers?). Finally, I create a rectangle shape (or circles) for slots and place them on "Mechanical" layer.

    The problem is that when I do the gerber for Mechanical layer I get both SMD pad (as it goes through all layers) and the slot shapes that are on Mechanical layer. As the SMD pad is larger than slots they hide the slots and the PCB manufacturer sees a huge pad and not the shape of the slot. 

    Am I doing something wrong, e.g. should I put PADs on top layer only, would this impact connectivity of tracks??

    As a side note, I find it difficult to select slot shapes as they are overlaid with smd pads and there isn't a way to cycle through overlapping components (eg. go to nearest or next shape on design).

    Below is what gerber and design look like

     

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  • Jayx .

    To cycle through overlapping elements press "n" on the keyboard.

    SMD pad shouldn't be on all layers, only copper layers (don't see the instruction saying to create it on all layers?).

    By the way, some update to my commnet from 01/10/2015 above (DSPCB team, may be worth to move it above, I can't do it myself): Some PCB manufacturers assume that if there is a pad on the copper layer then the slot is plated, if there isn't they will make it non plated.

     

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  • Nick M

    Thanks Jay!

    The screenshot in tutorial when creating pad shows layer drop box set to "all" so I assumed wrongly that's what it should be for the pad.

    However as my board is two layers and has copper at the bottom layer and top layer (bottom is used as ground plane and top for Vcc) then I guess I would need SMD to be on both Top and Bottom layer but *not* Mechanical layer.

    DesignSpark sadly can't specify that SMD is eg on Top and Bottom but not on mechanical. The layer options for the SMD pad can be either Top, Bottom, or All. This causes an issue and the manufacturer is basically saying they need layers as they should be without them having to tweak them manually,

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  • Jayx .

    Sorry, I've misunderstood. These slotted pads are actually not SMT, they are through hole and as such they need to be on all layers. If you get them on the gerber for the mechanical layer, then most likely you have mechanical layer set as "electrical" type or you have the options to include pads selected (see "Edit Layer Type" in the tutorial above for the correct settings for mechanical layer).

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  • Nick M

    Thank you very much! You are correct, the mechanical layer was not configured correctly. It was actually that I inadvertently skipped the step to define the layer type so my mechanical layer was of type 'none' which produced a bad result. Once I defined mechanical layer type as per steps above and assigned my mechanical layer to that type everything worked as expected.

    Thank you once again for your help!

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  • Andrea Modiano

    Thank you for this very valuable advice.

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