Rectangular holes

Making your own components and patterns, organizing and using libraries.
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chrisrossi
Posts: 5
Joined: 28 Aug 2014, 08:44

Rectangular holes

#1 Post by chrisrossi » 19 Sep 2017, 05:25

Hi, I'm trying to make a pattern to use for this part, using the recommended layout:

http://www.mouser.com/ds/2/393/rapc722x_cd-371352.pdf

I understand I can use oversized circular holes (the alternate layout), and I've done that, but it makes accurate positioning of the component difficult and is just sloppy.

What I've done is make pads as SMD pads, placed them on the bottom layer, and then added rectangular cutouts in the board outline layer. This seems like it should work, but a couple of issues I've noticed:

1) In the pattern editor, the pads obscure the cutouts entirely, so there's not really any way to visualize the cutouts in the pattern.
2) When using the pattern in a board layout, I get design rule errors because there is 0 gap between the pads and the cutout. I'd like to suppress those errors but still see errors when something is too close to the actual board outline.

Questions:

Is this a reasonable way to do this?

Is there a better way to do this?

If this is the way to do this, what are the solutions to the above issues?

Thanks!
Chris
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Here's the part placed in a PCB.  Note the DRC errors.
Here's the part placed in a PCB. Note the DRC errors.
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Tomg
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Joined: 20 Jun 2015, 07:39

Re: Rectangular holes

#2 Post by Tomg » 19 Sep 2017, 06:05

You can create oval through-hole pads with oval holes. Open up the Pattern Editor to the DipTrace standard libraries, select the "Con Power" library and take a look at the very first pattern ("4840-2211") to see an example.
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Tom

chrisrossi
Posts: 5
Joined: 28 Aug 2014, 08:44

Re: Rectangular holes

#3 Post by chrisrossi » 19 Sep 2017, 06:31

How do elliptical holes manifest in CAM? A bunch of overlapping drill holes?

Tomg
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Re: Rectangular holes

#4 Post by Tomg » 19 Sep 2017, 06:44

I believe they are routed slots.
Tom

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KevinA
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Joined: 18 Dec 2015, 08:35

Re: Rectangular holes

#5 Post by KevinA » 19 Sep 2017, 08:57

Tomg wrote:I believe they are routed slots.
Checkout http://docs.oshpark.com/submitting-orde ... and-slots/
I gave up and made tight round holes, they hold the part in place.
With OSH it is cheap to test things out, 20mmX20mm for $3 with shipping.

Just did a power connector: 490-PJ-002AH-SMT-TR mouser surface mount with locator pins, no play at all.
I did notice your center pin is a weird size, the above part has a 2mm standard pin but there are 2.1 and 2.5 also. This plug handles 3.5amp, yours has 5amp

Tomg
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Re: Rectangular holes

#6 Post by Tomg » 20 Sep 2017, 01:39

There is nothing arduous about creating plated-through-hole slots in DipTrace. Just select the appropriate settings in the Pad Properties dialog window, place the pad and you're done. All competent board houses will know what to do when they see your Gerber and drill files; no muss, no fuss. However, there is one board house that has reportedly made it difficult for customers wanting plated-through-hole slots. See this thread on another forum discussing OSH Park's apparently unique and atypical requirements for plated-through-hole slots - http://www.eevblog.com/forum/eda/plated-slots-again/. The last post in that thread is very interesting.
Tom

chrisrossi
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Joined: 28 Aug 2014, 08:44

Re: Rectangular holes

#7 Post by chrisrossi » 20 Sep 2017, 01:59

Yes, Osh Park is who I've been using for boards, because, except for this one issue, their pricing and service is hard to beat for small runs and prototyping. So, yeah, I was set on this path in part by their documentation, in part by it taking a second to realize that 'oval' != 'ellipse' in DipTrace speak (maybe call it a 'slot' in the UI?), and in part by not understanding drill files could do slots. I understand what's going on much better now than I did a day ago.

I have been emailing back and forth with Osh Park tech support in order to fully understand the issue and their requirements. They say they are working on the problem, so they know their tools are behind the curve here. I have no idea if they'll have it fixed next week or in 5 years. Basically, putting the slot in the board outline is a workaround for their tooling deficiency, and even then, it requires a human operator, during panelization, to spot the slots and manually convert them, which is why the say it should work, but no guarantees. Which is, obviously, frustrating. Their 3 board pricing is hard to beat, though, so it might be worth the gamble for the prototyping phase, but it's obviously unacceptable if you need any quantity.

All that said, who else should I be looking at for small run/prototyping?

Thanks!
Chris

Tomg
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Re: Rectangular holes

#8 Post by Tomg » 20 Sep 2017, 02:33

I don't have enough "vendor experiences" to be of any help in this matter. Just in case you didn't know, here is a website that will let you sort through current prices - https://pcbshopper.com/
Tom

chrisrossi
Posts: 5
Joined: 28 Aug 2014, 08:44

Re: Rectangular holes

#9 Post by chrisrossi » 20 Sep 2017, 03:19

Tomg wrote:I don't have enough "vendor experiences" to be of any help in this matter. Just in case you didn't know, here is a website that will let you sort through current prices - https://pcbshopper.com/
That's useful, thank you!

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