Re: [Emc-users] Probably Dumb questions of the week, about inkscape

[Edward B. <yan...@ya...>]

Just out of curiousity Gene, why are you trying to use Inkscape for PC boards when you could use Kicad, gEDA or the free version of Eagle?




>________________________________
> From: gene heskett <ghe...@wd...>
>To: emc...@li... 
>Sent: Friday, December 30, 2011 12:30 PM
>Subject: Re: [Emc-users] Probably Dumb questions of the week, about inkscape
> 
>On Friday, December 30, 2011 09:56:25 AM Ben Jackson did opine:
>
>> On Thu, Dec 29, 2011 at 09:00:50PM -0500, gene heskett wrote:
>> > I haven't fooled with inkscape in probably 5 years, but back then I
>> > could compose dots and bars and place then, however with NDI what the
>> > scale was, it appeared to be completely arbitrary at the time.
>> 
>> The default scale is usually pixels.  You can change the display of it
>> in a pulldown (just above the image area).  You can change the default
>> for your document in the document properties.  I've made a template for
>> my laser cutter which has a document in mm with a "page size" equal to
>> the cutting area.
>
>I am not sure how wide & high this board will be, but I have made what 
>looks to be a usable starting blank page for one copy of this.  I guess I 
>am at the rank beginner stage, and can't see the tree I need in that forest 
>of buttons.  Everytime I look at a gfx composition program it seems the 
>biggest hurdle is setting the size of the project in units to match EMC, 
>which is running in inch mode here in the middle of the WV hills.  At least 
>I think I have everything set to inches now, and have a view that is about 
>2/3rds screen for a board a bit larger than an airmail stamp.  Thanks for 
>the detailed location of what I needed to modify.
>
>> > So, how do I draw these things to make up a PCB trace without those?
>> 
>> To draw PCB traces I'd use one of the line tools on the left.  One of
>> them makes straight lines as long as you don't click and drag when
>> placing points.
>
>The first thing I need to do is setup a layer that can later be removed, 
>which contains the 12 holes I have already drilled in the board to mount 
>the parts, and to clear the leads of the parts.  Those holes are .125" in 
>diameter and now that I have changed every place I've found px settings 
>reset to inch, the best way to place them is via the centerpoint 
>measurements EMC already used to position the drill before drilling.  But 
>that doesn't seem to be available, so I have to calculate the left and 
>lower boundaries by subbing the radii, and enter the x,y diameters instead.  
>kcalc to the rescue. :)
>
>So this is this a place circle, then adjust its properties to fine tune the 
>location and size.
>
>But I've now drawn to a reasonable accuracy (the curser location display on 
>the lower right only being 2 digits is a PIMA) the pattern to mount one 
>interrupter, is there a way to copy all 4 holes and stamp them down at 
>.340" spacings 2 more times?
>
>That would sure beat the heck out of the 3 hours I got in putting down 4 
>.125" diameter circles where the mounting and lead clearance holes are.
>
>Obviously I'm missing something that is going to bite me shortly, if not 
>already. :)
>
>Silly Q, has this generated a procedure file that can be edited, then 
>reloaded?
>
>Once I have that, then the end holes of each pattern (another layer of this 
>drawing) need excavated to the diameter of the screw heads + about 20 thou, 
>to a depth that is below the copper by 10 thou or so, which will insulate 
>the screws and give me another half a thread of nut penetration.  This can 
>be done with a .125" 2 flute mill.  So that will be layer2.
>
>I hope to be able to arrive at a 3 or 4 layer image, each layer of which 
>can be exported to emc as gcode and carved once the proper bit is in the 
>spindle.  Layer 1, the mounting holes. is already done.
>
>The room on the pcb left from layer1, then layer2's screw head isolation, 
>is the room I'll have to actually build circuit traces with.  It may also 
>require a vacuum table to be built to hold it as flat as possible, and that 
>used as a precision holding jig.  I figure the first one goes in the trash, 
>its a tool to learn how to do it.  Plus the shack has more pcb material. :)
>
>If push comes to shove, it might be possible to switch to 2-56 screws, 
>which should allow the cells to be pushed around a bit to fine tune the 
>quadrature pattern obtained when the spindle is at speed. Some room for 
>that is available with 4-40 screws, perhaps 20 thou.
>
>Now, off topic for this discussion......
>
>Silly Q to the folks who did the encoder modules index logic:
>How to you define which edge of the Z pulse to call 0 degrees?  With my 
>wheel size limitations, that error on reversal is at least 2 degrees if it 
>zero's only on the down edge.
>
>It seems to me that what it should be doing is looking for the edge, not 
>the pulse, which we can diddle cell locations such that the CW edge of the 
>z slot in the wheel always occurs when A=B=0 in the cycle.
>
>Or am I way behind the thinking here and it already does this?  The 
>integrators manual doesn't appear to get into that fine a detail.
>
>Back on subject:
>
>> Then bring up the format menu (ctrl-shift-F) and set
>> the width and corner style to whatever you want (turn fill off).
>
>Not for the first 2 layers, I need to see it.  I haven't tried but I 
>presume I can color each layers objects to help visualize.
>
>> If
>> you want traces to be outlines you can use "convert stroke to path" in
>> the Path menu which will use your line width/join settings and create a
>> new polygon where the filled area is what the stroked area of the line
>> was.
>
>That worked to give me a view of the holes that actually looks like a hole, 
>and I just found the menu item that allows data entry for positioning, but 
>it seems to be disabled once this stroke conversion is done.  And because 
>it rounds to the nearest thou, I can see some slight positioning errors I 
>cannot now correct.  The present screen scale is 747%.
>
>> To edit lines use the second tool (below the "select" tool) which is the
>> "node" tool".  That will let you move intersections and add/delete them.
>
>> 
>> > Also, to serve as the anchoring image, how can I get the hole pattern
>> > emc has already drilled, into a format that shows the actual diameter
>> > of the holes I have already drilled, into a format inkscape can
>> > import as dots of missing material?
>> 
>> You can import and scale an image.  Put it on another layer and lock the
>> layer (even make it partially transparent).
>
>Do I need potrace installed for that, or is it build in?  I note that one 
>of the functions 'based on potrace' doesn't seem to work.
>
>> If you have an Excellon drill file and some python programming expertise
>> you could write a plugin to import them as circles.
>
>No, sorry, neither.  So I'm doing this by hand, with kcalcs help.
>
>As I close this message, my next question is "how to multi-select the 4 
>objects I have, so that I can paste them down at X increment intervals of 
>.340" to complete the other two cell mounts?"
>
>I did this, but one hole at a time, so that is done and saved as drill-
>holes-layer1
>
>But now I have added another layer on top of that one, but don't seem to be 
>able to draw in it, and it is selected according to the caption at the 
>bottom of the screen.  All I seem to be able to get are the handle boxes.
>
>Thanks a bunch. I appreciate the help, I might eventually grok this thing 
>yet.  :)
>
>Cheers, Gene
>-- 
>"There are four boxes to be used in defense of liberty:
>soap, ballot, jury, and ammo. Please use in that order."
>-Ed Howdershelt (Author)
>My web page: <http://coyoteden.dyndns-free.com:85/gene>
>"Linux: the operating system with a CLUE...
>Command Line User Environment".
>(seen in a posting in comp.software.testing)
>
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