Author Topic: Removing string overlay from pads  (Read 750 times)

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Offline angust_uk

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Removing string overlay from pads
« on: May 17, 2019, 05:33:32 pm »
Hi all

I have a layout (in AD17) with a large piece of text on the Overlay layer, which sits over some component's pads. I'm trying to get Altium to trim the Overlay such that it is does not break the 'Silk to Soldermask' rule, which of course it currently is as the silk is right over the top of all the pads. If it were a polygon I could simply use a cutout, but is there anything similar for a string?

In case it's not clear from my half-arsed description, the image below is an example what I'm working with; I'd like Altium to generate the Gerbers with cutouts on the silk layer where the soldermask cutouts are such that the bit of silk over the pads, circled in blue, is not plotted.

Any help would be greatly appreciated!
 

Offline tboy

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Re: Removing string overlay from pads
« Reply #1 on: May 17, 2019, 06:23:54 pm »
My wife, who knows absolutely nothing about PCB layouts. suggests you move the text, or make it smaller so it doesn't overlap the pad.  She also wonders why would consider a text string with a hole in the middle acceptable. If this was a fishing expedition then you caught one.  If it is somehow more complicated then you need more of an explanation. :)
 

Offline angust_uk

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Re: Removing string overlay from pads
« Reply #2 on: May 17, 2019, 06:40:14 pm »
Ok, looks I wasn't clear enough! The screenshot was an example - in the actual layout I have the text is very large (in fact it's a logo, but the easiest way to import a vector image is via a TrueType font), and I have LEDs placed over it.

The original point is the same (ignoring the image I posted which may be confusing things) - is there a way to create a cutout in a text string on the silkscreen layer?
 

Offline ddavidebor

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Re: Removing string overlay from pads
« Reply #3 on: May 17, 2019, 08:04:53 pm »
Hi,

I am pretty sure there is no such functionality.

Maybe you can convert the text to primitives using the convert function (i haven't tested if it works)
Davide Bortolami,
Fermium LABS srl
 
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Offline julianhigginson

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Re: Removing string overlay from pads
« Reply #4 on: May 21, 2019, 01:44:29 am »
well, you can leave it as is if you have to, and inform the PCB fab in the fab spec you also deliver, that they need to do that cutout of the overlay for you.
Most will want to do that automatically anyway because, well, overlay on pads is a bad look for them.

 
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Offline T3sl4co1l

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Re: Removing string overlay from pads
« Reply #5 on: May 21, 2019, 02:44:55 am »
Possibly a very cheap (or very literal?) fab will not remove silk-over-pads, but my experience has been, the popular fabs always remove it.  As mentioned, make sure by adding the instruction on the fab or drill drawing, or in an accompanying text file. :)

Tim
Seven Transistor Labs, LLC
Electronic design, from concept to prototype.
Bringing a project to life?  Send me a message!
 
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Offline angust_uk

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Re: Removing string overlay from pads
« Reply #6 on: May 21, 2019, 07:35:34 am »
Thanks all for the advice. Tim & Julian: yes, this is what I was hoping for once I realised I couldn't remove it myself (though I'm using JLCPCB, so not entirely convinced they'll do it!).

Worst case scenario is I have to break out the scalpel and start scraping!

 

Offline Psi

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Re: Removing string overlay from pads
« Reply #7 on: May 21, 2019, 08:18:31 am »
Everyone i know who uses Altium simply doesn't position silkscreen text over their pads.
Greek letter 'Psi' (not Pounds per Square Inch)
 

Online thm_w

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Re: Removing string overlay from pads
« Reply #8 on: May 21, 2019, 11:47:46 pm »
Thanks all for the advice. Tim & Julian: yes, this is what I was hoping for once I realised I couldn't remove it myself (though I'm using JLCPCB, so not entirely convinced they'll do it!).

Worst case scenario is I have to break out the scalpel and start scraping!

They will do it without any requests or notes for sure. Question is if anything else gets screwed up or not.

They also changed a bunch of my hole sizes, cut off edges of pads, etc. nothing actually bad, but first time I'd seen it.
Clipping silkscreen with pad locations is one of the most basic feature of any CAM processing software.
 
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Offline mengfei

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Re: Removing string overlay from pads
« Reply #9 on: May 27, 2019, 09:39:39 am »
we have PTH that are really close to each other & just placed a whole silkscreen above the pads totally covering it but when the PCB comes those pads wont be covered by the silk screen.

I think it's by default that they, our vendor, have a process that as long as it is a component pad/ soldered pad & has soldered mask No Silkscreen will be over the pads. 
 
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Offline angust_uk

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Re: Removing string overlay from pads
« Reply #10 on: May 28, 2019, 01:38:56 pm »
Thanks everyone for the input - as it turns out JLCPCB did indeed remove the silk from the pads (despite telling me that they do not modify the supplied Gerber data in any way!)
 

Offline ddavidebor

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Re: Removing string overlay from pads
« Reply #11 on: July 15, 2019, 08:49:24 pm »
Thanks everyone for the input - as it turns out JLCPCB did indeed remove the silk from the pads (despite telling me that they do not modify the supplied Gerber data in any way!)

Hi Angust

Unfortunately there is no such thing as pcbs from unmodified gerbers. A Pletora of automated modification is ALWAYS applied to compensate for the inevitable tolerance of etching and drilling.
This is something that is not possible to avoid with any manufacturer.

Almost all manufacturers will remove silk from the pads by default. You should not see this as them lacking compliance to your requirements, but you lacking compliance to industry standards.
If you want silk on pads, ask a more pricey manufacturer explicitly and they will do it. (or tell you it's not an option).

David
« Last Edit: July 15, 2019, 08:51:32 pm by ddavidebor »
Davide Bortolami,
Fermium LABS srl
 


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