Area pocketing tuturial

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Area pocketing tuturial

Сообщение Nick » 25 авг 2010, 12:01

This tutorial will cover one of the ways to create area pocketing using Inkscape and Gcodetools.

What do we have: a bitmap with with logo.
What do we want: cut it from piece of material with 0.125 cutter.

Preparing the bitmap


Original bitmap:
Area pocketing tuturial image001.jpg

Open it with Gimp (Gimp is a graphics editor powerful as Photoshop and free as Inkscape. http://www.gimp.org).
Area pocketing tuturial 0001 gcode area pocketing gimp theshhold.jpg

And apply Colors->Threshold...
Area pocketing tuturial 0002 gcode area pocketing gimp theshhold.png


Trace image using Inkscape


Add image to the Inkscape:
Area pocketing tuturial 0003 gcode area pocketing inkscape trace bitmap.png

Select it and Apply Path->Trace bitmap... with the following parameters:
Note the Remove BackGround checkbox!
Area pocketing tuturial 0005 gcode area pocketing inkscape trace bitmap.png
Area pocketing tuturial 0007 gcode area pocketing inkscape trace bitmap.png

You should got the following:
Area pocketing tuturial 0004 gcode area pocketing inkscape trace bitmap.png
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Re: Area pocketing tuturial

Сообщение Nick » 25 авг 2010, 12:25

Prepare the path


It will be useful to Break path apart because different parts will need different options.
So do Path->Break apart or press (Ctrl+Shift+k) I definitely recommend to use shortcuts it will increase your working speed.
That's what you'll see:
Area pocketing tuturial 0008 gcode area pocketing inkscape prepare the path.png

It's not good. We have to fix that hole.
There's 2 ways to fix it:
1. Edit nodes using node tool (F2).
You'll need to break path at th selected points (using the button in the toolbar that shows one node become two not connected nodes)
Move nodes to correct the error
And then join selected end nodes with a new segment.
Area pocketing tuturial 0011 gcode area pocketing inkscape prepare the path.png

2. Or just draw a patch using Bezier tool (Shift+F6) and then add it to original path (Ctrl+Shift+"+").
Area pocketing tuturial 0010 gcode area pocketing inkscape prepare the path.png


Break path apart
Remove fill from the path and add stroke and press Ctrl+Shift+K.
Area pocketing tuturial 0013 gcode area pocketing inkscape prepare the path.png

Clear some dust:
Set stroke width to 5px or larger to see the dust better.
Area pocketing tuturial 0015 gcode area pocketing inkscape prepare the path.png


Combine path together
We want to combine paths together in several paths which we will offset separately.
I suggest to create 4 paths:
1. Points that are near the biggest circle.
2. Text
3. Circles
4. The map
So select all the "points". You can use a brilliant Inkscape's feature "select by touch". Press Alt+Shift and start drawing over the paths you want to select.
Then pres Ctrl+K to combine the paths. You can add fill color to be sure that all paths are combined properly. I've forgot to select one hole from the "B" letter and combined it later. (Just select them again and press Ctrl+K.)
Area pocketing tuturial 0017 gcode area pocketing inkscape prepare the path.png

I've add different colors to different path types:
Area pocketing tuturial 0018 gcode area pocketing inkscape prepare the path.png

Here's svg that you should got:
Вложения
gcode area pocketing.svg
(116.44 Кб) Скачиваний: 754
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Re: Area pocketing tuturial

Сообщение Nick » 25 авг 2010, 13:36

Offset the path


The hardest thing while calculation pocketing is to offset the path. It's really hard to be calculated and often gives bad result. For simple paths offset could be easier and for them you could try to use Gcodetools axiomatization. But this path is really bad one, so we'll better offset it by hand.

There are two ways to create offset in Inkscape. First dynamic offset - it fast but nasty. Other doing offset one by one using Path->Inset (Ctrl+"(") and Path->Outset (Ctrl+")"). This way gives more clear offset.

So lets start.

First press Ctrl+Shift+P to open preferences dialog. Go to Steps section.
We'll need to configure Inset/Outset value.
If we use 0.125 inch cutter first offset should be at 0.0625 inch it is exactly 5,625 px. 1inch = 90 px.
Insert 5.625 to Inset/Outset value. Do not close the dialog we'll need it in some seconds so just make it smaller.
Select the path and press Ctrl+"(". You'll see that path has been offsetted. We've made our first cutting path.
Area pocketing tuturial 0020 cam area pocketing inkscape.png

From now we can increase offset step up to 0.125in or 11.25px. But we can use smaller value from the one side it would increase loops number, but from the other we'll get better cut.
Let's use 10px as offset step. So enter 10 into the preferences dialog.
Select the path and make a copy of it by pressing Ctrl+D.
Then create new offset by pressing Ctrl+"(".
Continue pressing Ctrl+D and Ctrl+"(" until path disappears.
You should see something like this:
Area pocketing tuturial 0021 cam area pocketing inkscape.png


If you see some errors you can try just change the offset step a bit, for example from 10 to 10.1 px

Proceed to other paths:
Text
Text has many thin places and corners so I recommend to do all offsets using 5.625 offset step.
Area pocketing tuturial 0022 cam area pocketing inkscape.png

Map
To male map's line more sharp I recommend to live one copy unoffsetted path. It would make the line thicker but more accurate.
As we have left original path we can start with 10px offset step.
Area pocketing tuturial 0024 cam area pocketing inkscape.png

Circles
We can cut the circles as is.

Finally the path is ready


It took me about 5 min to create the path and 2 hours to write it all down :). Probably it would take you longer to reed this path than do it yourself :D.
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Re: Area pocketing tuturial

Сообщение Nick » 25 авг 2010, 13:53

Now let's export our paths to Gcode!


We'll need:
  • A tool to cut with
    Create a tool. Go to Extensions -> Gcodetools -> Tools library. You can chose cylinder or default tool. Press apply.
    A new tool will be created.
    You can change the parameters using Text tool "F8". After you've change the parameter do not press "enter" just click somewhere else or chose select tool (F1).
    All you have to fill in are feed, penetration feed and depth step.
    Area pocketing tuturial 0027 gcode tools tool library.png
  • 2 orientation points
    Create orientation points. Go to Extensions -> Gcodetools -> Orientation. Fill in surface and depth values. (Surface 0, depth -.2). And click add.
    You should get something like this:
    Area pocketing tuturial 0028 gcode tools tool library orientation points.png

    Unfortunately due to some improvements Orientation points do no take into account that you are using inches.
    I'll fix it soon. But you can fix it manually.
    Move orientation group along X axis to 0.0
    Area pocketing tuturial 0030 gcode tools tool library orientation points.png

    Double click at right arrow to go into the orientation group. Click at right arrow to select arrow and the text. And move it along X axis to 10in.
    Area pocketing tuturial 0031 gcode tools tool library orientation points.png

    Using Text tool (F8) change (100.0; 0.0; -0.20000000298) to (10.0; 0.0; -0.20000000298).
    Do not worry about this value "-0.20000000298" it's the most accurate interpretation of -0.2 by floating point it wont mess up :)!
    Area pocketing tuturial 0032 gcode tools tool library orientation points.png
  • Some setting up
    Open Extensions -> Gcodetools -> Path to Gcode
    Go to Preferences tab. Set up "directory", "Z distance over blank", "units".
    Go to Path to Gcode tab. Set up "Biarc interpolation tolerance" with '0.01".
Area pocketing tuturial 0034 Cam Path to Gcode.png

Press Apply and you should get the Gcode!


Area pocketing tuturial Снимок--home-nick-Design-cnc-club.ru-tutorials-gcode area pocketing.svg - Inkscape-2.png
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output_0006.ngc
NGC file 1.7Mb.
(1.3 Мб) Скачиваний: 617
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Re: Area pocketing tuturial

Сообщение Durachko » 30 авг 2010, 17:57

Thanks root! I'll see if I can help out on this forum a little bit when I find some time. Once I get this logo "perfected" I'll post pictures and video and info on any changes I've made to your output.
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