Author Topic: Internal cut out came out wrong  (Read 2792 times)

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Offline CCB

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Internal cut out came out wrong
« on: August 17, 2017, 08:56:55 am »
Hi Everyone,

I spent a bit of time learning to use Kicad and I've just had my first PCB arrive back!

I was pretty excited until I saw the internal cut out wasn't what I was expecting.  :(

I used 2 circles and then a shape to join them togeather. Did I do this wrong? I assumed the mill would cut the circles and then bit between them? I put these on the edge cuts layer the same as the outside of the board.

I checked the gerber files with a non kicad viewer (not 3d) and it looked ok.

I've manually cut the section out but it makes be wonder for the next board where I went wrong? Any suggestions or how to? Does this need to be merged in to one shape?


Thanks,
Carl
« Last Edit: August 17, 2017, 09:00:29 am by CCB »
 

Offline ElectronicCat

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Re: Internal cut out came out wrong
« Reply #1 on: August 17, 2017, 09:20:09 am »
Is that an OSHPark board? If so, check out the internal cutout guidance page and general KiCad help page. At least it looks like an easy fix.
 

Offline Rerouter

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Re: Internal cut out came out wrong
« Reply #2 on: August 17, 2017, 09:32:15 am »
While i agree it should have conveyed it, I would have used arcs, In the past i have marked with text on the layer "cutout area",
 

Offline CCB

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Re: Internal cut out came out wrong
« Reply #3 on: August 17, 2017, 09:46:24 am »
Thanks, I got them made by Elecrow. The pricing is great and the apart from the cut out I'm happy with the quality.

I think I might try to use a single shape with arcs like you suggest and mark it with 'cut out' text next time :) At least now I know.
 

Offline firewalker

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Re: Internal cut out came out wrong
« Reply #4 on: August 17, 2017, 09:52:02 am »
You should check Elecrow page for cututs. The rules above is for OSHpark.

Alexander.
Become a realist, stay a dreamer.

 

Offline donotdespisethesnake

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Re: Internal cut out came out wrong
« Reply #5 on: August 17, 2017, 07:20:11 pm »
Yes, always ask the fabber for how to specify milling.  https://www.elecrow.com/wiki/index.php?title=Q%26A_for_PCB_service
Quote
Q: What the minimum distance between two panelized PCBs?
A: Zero distance is recommend.

    ps1: The milling cutter can only run straight line. And the V-groove straight line should through the whole board.

Not sure if that applies to internal cutouts, but would if they applied that rule might be consistent with what you received. Or maybe they just got confused as to what they are seeing. Gerbers do not convey the information well.

Either way, I would draw the cutout as a single contour. You might find it easier to draw a DXF and import it.
Bob
"All you said is just a bunch of opinions."
 

Offline tycz

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Re: Internal cut out came out wrong
« Reply #6 on: August 18, 2017, 03:02:36 am »

I used 2 circles and then a shape to join them togeather. Did I do this wrong? I assumed the mill would cut the circles and then bit between them? I put these on the edge cuts layer the same as the outside of the board.

You wanted only one shape cut. Instead of drawing the shape you wanted, you drew three different shapes on top of one another. The CAM engineer/operator (who is a human, not a machine) was confused by this. Try to be unambiguous next time.
 

Offline rs20

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Re: Internal cut out came out wrong
« Reply #7 on: August 18, 2017, 04:11:45 am »
You specified the shapes incorrectly. You wanted a single shape consisting of 2 arcs and 2 lines, forming a single, simple, closed shape defining the hole. Instead, you sent a whole mess of self-intersecting shapes such that no human or machine can unambiguously figure out which parts of the board should be present or not.

Specify your edge layer such that EVERY line and arc actually delineates a border between PCB and air (unlike, for example, the horizontal lines in your picture which delineate absolutely nothing, they are supposed to have air on either side of them), and such that every line/arc is connected to precisely one other line (unlike, for example, the points at the end of your horizontal lines which have FOUR lines/arcs intersecting at a point, what the hell is that supposed to mean?) and you'll have no problems.

I mean, I bet you were thinking while you were drawing this at the design stage, "I assume they'll get what I mean by this, right? Right?". Well, now you've learned an important lesson for delivering engineering design artifacts -- never leave any scope for misinterpretation.
« Last Edit: August 18, 2017, 04:14:38 am by rs20 »
 


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