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Topic: Size of nibs used to create panels (Read 1940 times) previous topic - next topic

Size of nibs used to create panels

I've put quite a few panels through DirtyPCBs and had no issues until the last one where the board house rejected it as they said the nibs were too small. I increased the size to about double what I normally use and they accepted them, but when I got the boards back they have obviously tinkered with the routing and increased some of the nibs massively, to the point where they are much too big to cut.

Two questions, first, has anyone else used nibs and what size have you used with success. And second, I've seen others use mouse-bites. How are these created? I use DesignSpark and I can see no way to place a hole without an associated pad and also DirtyPCBs doesn't seem to be able to do non-plated holes (presumably as this is an extra stage in the PCB production process and so costs more).

Re: Size of nibs used to create panels

Reply #1
Until now, in all of my designs the non-plated holes were done correctly. Either you really had bad luck with your boards, or there's something with your layout so that they made the wrong decision. It's important that the holes aren't sorrounded by any copper in the layout.

Re: Size of nibs used to create panels

Reply #2
How do you specify non-plated holes? I should clarify I've not tried non-plated holes before as I'd read somewhere (although I can't find where) that DirtyPCB doesn't support non-plated holes to keep the cost down.

DesignSpark creates two separate files, one for plated holes and one for unplated. I actually have to merge the two files sometimes as there are some holes created unplated which I need to move in to the plated file otherwise they don't get drilled. If I can send both and they definitely get used (rather than the unplated holes being omitted) then I'll do that.

Re: Size of nibs used to create panels

Reply #3
Mills / holes are not plated.  Vias are plated.

Sometimes dirtypcbs plates my mounting holes that are supposed to be not plated. Not a problem for me.  I am sure they make the decision based on what other stuff they making at the same time.

Re: Size of nibs used to create panels

Reply #4
That's my point - what data do we need to send them to get unplated holes? Milling data is in a different file from drilling data and milling and drilling are different stages in the PCB production process. I generally create mounting holes as milled rather than drilled so they won't be plated, mousebites are too small to mill and need drilling.

There is an option in DSPCB for a pad to be 'Unplated' - however this creates two drill files. For a board house to do unplated holes they need to drill the board, plate it then drill again. This extra stage adds cost and my understanding (although it would be helpful if someone from DirtyPCB could confirm) is that this stage isn't part of the spec and if we include an 'Unplated holes' file it is down to the board house if they use it or not.

Re: Size of nibs used to create panels

Reply #5
I can't tell you how you can do that in your PCB layout software. You should use a gerber viewer (gerbv) to take a close look at the produced gerber files:

For DirtyPCB, all holes (plated and unplated) should be in one *.TXT file. This should be an Excellon file.
The board outline and all milling data should go into a *.GML file. To avoid confusion, all lines in the GML file should be drawn with width zero.
The board house will use the gerbers for the top and bottom layer to decide if holes and millings are plated or non-plated when they prepare their manufacturing data. If there's no copper around a hole on both layers, they will be non-plated, otherwise they will be plated.

Re: Size of nibs used to create panels

Reply #6
OK, looks like I can't do unplated holes (or at least not ones too small to be milled) as DesignSpark can't place holes without pads so there will always be copper.

I guess for mousebites it probably doesn't matter if they plate or not in most cases.

Re: Size of nibs used to create panels

Reply #7
There are some hints and youtube videos how non-plated holes can be done in DesignSpark.

Re: Size of nibs used to create panels

Reply #8
[quote author="barakandl"]Mills / holes are not plated.  Vias are plated.

Sometimes dirtypcbs plates my mounting holes that are supposed to be not plated. Not a problem for me.  I am sure they make the decision based on what other stuff they making at the same time.[/quote]

This is my experience too. however it has been some time I had plated holes.

 

Re: Size of nibs used to create panels

Reply #9
[quote author="eauth"]There are some hints and youtube videos how non-plated holes can be done in DesignSpark.[/quote]

I'll have to keep looking as I can't find any that don't do as I describe and still place copper with the intention of the drill removing it - which often doesn't work as the alignment is never spot on.

I feel this is something missing from DS - it would be so easy to place a drill only with no associated pad but for some reason they don't want to add this feature.