Lasercut

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Lasercut

bmsleight
Hi,

I made a library to help me use OpenSCAD for laser-cut models

https://github.com/bmsleight/lasercut

Features which can be intermixed:-
 * Simple rectangles, or points on a poloygon
 * Simple tabs and tab holes
 * Captive nuts - both parts
 * Box with 4,5 or 6 sides
 * Finger joints
 * Add or remove circles, make a slit or cut-out a rectangle
 * Automatic 3d to 2d layout

The key feature for myself is to generate a 2d files automatically
from the 3d-model, which can uploaded to a laser-cutter. I am not
using python or perl, but using OpenSCAD and the children function to
generate a OpenSCAD file which is 2d and re-uses the library.

Full Readme with examples and images:-
  https://github.com/bmsleight/lasercut/blob/master/README.md

Thanks for OpenSCAD.
Regards,
Brendan

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Re: Lasercut

glennswest
This is soooo nice.

Also great for cnc

Few more joint types would be nice

Even doing large objects that are 3d printed it would be useful



Sent from my iPhone

> On 15 Oct 2015, at 7:20 am, Brendan Sleight <[hidden email]> wrote:
>
> joints

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Re: Lasercut

jon_bondy
OpenSCAD is my preferred method for designing 3D objects for printing.  
The novel thing about the original link I provided is that it is devoted
to creating 2D objects for laser cutting. If you want to learn more
about OpenSCAD, Google the documentation, manuals, and tutorials.  Or
invite me to teach an OpenSCAD course at Generator again.

Jon

On 10/14/2015 8:53 PM, Glenn West wrote:

> This is soooo nice.
>
> Also great for cnc
>
> Few more joint types would be nice
>
> Even doing large objects that are 3d printed it would be useful
>
>
>
> Sent from my iPhone
>
>> On 15 Oct 2015, at 7:20 am, Brendan Sleight <[hidden email]> wrote:
>>
>> joints
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Re: Lasercut

bmsleight
In reply to this post by glennswest
glennswest wrote
Few more joint types would be nice
Which joint types would you like to see ?

BMS
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Re: Lasercut

glennswest
http://m.instructables.com/id/50-Digital-Joints-poster-visual-reference/

Lot of good ones here

Sent from my iPhone

> On 16 Oct 2015, at 6:22 am, bmsleight <[hidden email]> wrote:
>
> glennswest wrote
>> Few more joint types would be nice
>
> Which joint types would you like to see ?
>
> BMS
>
>
>
> --
> View this message in context: http://forum.openscad.org/Lasercut-tp14126p14137.html
> Sent from the OpenSCAD mailing list archive at Nabble.com.
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Re: Lasercut

runsun
Very cool thing, but it looks to me that those digital joints are for superman, not for human being. :) (or if you are human with a CNC). Some of them don't even make sense, if you look closely, either it seems to leave gaps, or the geometry doesn't seem to allow them to join together, unless they have magic that I don't see.

For the purpose of designing joints with Openscad, I would suggest choosing those that are more commonly used by woodworkers, like those in :

http://woodtools.nov.ru/mag/good_wood_joints/good_wood_joints.htm
$ Runsun Pan, PhD
$ libs: scadx, doctest, faces(git), offline doc(git), runscad.py(2,git), editor of choice: CudaText ( OpenSCAD lexer); $ Tips; $ Snippets
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Re: Lasercut

Neon22
In reply to this post by bmsleight
In my Lasercut work I have used Ponoko a lot - they use SVG direct from
Inkscape.
In my extensions for Inkscape (jigsaw, tabbed box)I have added a Kerf
parameter as well. This is useful to get perfectly fitted parts. The
offset for the kerf has to be calculated carefully for internal and
external edges so the parts fit perfectly but maintain their correct
outer dimensions.
Do you think it would be a useful feature to add ?

Also - because I have kerf - sometimes the user doesn't want that and
prefers a sloppy fit but with a minimal number of cuts (lowest cost).
I.e. so the pieces are placed directly adjacent to each other and only a
single line is put into the export file. So no double lines to cut the
same edge. This lowers the cost of lasercutting quite a lot for most
pieces but of course its a tradeoff with the sloppy fit.

Have you considered this in your fit and export options also ?

One more option I added was the ability to put in small half round so
that the sloppy fit pieces could be press fitted. This is no good for
perspex which cracks but perfect for wood which can sustain minor
deformation.

Looks really interesting so far. Nice work.
Cheers...

On 10/15/2015 12:20 PM, Brendan Sleight wrote:

> Hi,
>
> I made a library to help me use OpenSCAD for laser-cut models
>
> https://github.com/bmsleight/lasercut
>
> Features which can be intermixed:-
>   * Simple rectangles, or points on a poloygon
>   * Simple tabs and tab holes
>   * Captive nuts - both parts
>   * Box with 4,5 or 6 sides
>   * Finger joints
>   * Add or remove circles, make a slit or cut-out a rectangle
>   * Automatic 3d to 2d layout
>
> The key feature for myself is to generate a 2d files automatically
> from the 3d-model, which can uploaded to a laser-cutter. I am not
> using python or perl, but using OpenSCAD and the children function to
> generate a OpenSCAD file which is 2d and re-uses the library.
>
> Full Readme with examples and images:-
>    https://github.com/bmsleight/lasercut/blob/master/README.md
>
> Thanks for OpenSCAD.
> Regards,
> Brendan
>
> _______________________________________________
> OpenSCAD mailing list
> [hidden email]
> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2015.0.6172 / Virus Database: 4447/10819 - Release Date: 10/14/15
>
>


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tp3
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Re: Lasercut

tp3
Von: "Mark Schafer" <[hidden email]>
> Also - because I have kerf - sometimes the user doesn't want that and
> prefers a sloppy fit but with a minimal number of cuts (lowest cost).
> I.e. so the pieces are placed directly adjacent to each other and only a
> single line is put into the export file. So no double lines to cut the
> same edge. This lowers the cost of lasercutting quite a lot for most
> pieces but of course its a tradeoff with the sloppy fit.
>
I think that's currently not possible, at least not without additional
postprocessing. The 2D behavior matches the one from 3D where touching
parts are unioned into a single one, so a line separating two 2D objects
(e.g. "square(10); translate([10, 0]) square(10);" will just result
in a single 10x20 rectangle).

I guess the interesting question is how to integrate better lasercut
support into the language without breaking existing models.

ciao,
  Torsten.

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Re: Lasercut

bmsleight
In reply to this post by Neon22
Neon22 wrote
In my extensions for Inkscape (jigsaw, tabbed box)I have added a Kerf
Do you think it would be a useful feature to add ?
Yes useful to add, but hard :)
I will have a think.

Neon22 wrote
prefers a sloppy fit but with a minimal number of cuts (lowest cost).
Have you considered this in your fit and export options also ?
No. For the reasons stated by tp3. I have only used Ponoko a few times, and found the saving for single lines not worth the effort and cost of making a mistake. (But the pricing model may have changed since ~2012)


Neon22 wrote
One more option I added was the ability to put in small half round so
that the sloppy fit pieces could be press fitted. This is no good for
perspex which cracks but perfect for wood which can sustain minor
deformation.
Could you explain in more detail or point towards an image/example. Should be easy to add.

Cheers,
Brendan
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Re: Lasercut

Neon22
Here is a blowup of some oversize dimples on a tabbed box.
In my extension I made their size based on the Kerf parameter as its serves a similar purpose.
The Dimple shape here is a flattened oval. When printed in wood the dimple will crush a little and ensure a press fit.
I also have a design option where this is a triangle. This shape can crush a lot more. Still no good for Acrylic. Only useful for Wood and Cardboard.
dimples

As an aside - Ponoko's costs are based on the material and the lasertime. So removing all double lines can make quite an impact on the laser side of the costs. However its also critical to arrange the svg entities in order of minimal distance travelled by the laser as it traverses the pattern. This is not a Ponoko specific issue - it applies to all lasercutting.
However there is no support in inkscape for this CAM type of reordering and so minimal lines might not show a significant cost reduction if the line traversal is pathological.
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Re: Lasercut

bmsleight
Neon22 wrote
The Dimple shape here is a flattened oval. When printed in wood the dimple will crush a little and ensure a press fit.
I also have a design option where this is a triangle. This shape can crush a lot more. Still no good for Acrylic. Only useful for Wood and Cardboard.
dimples
Added
dimples

Also added the joints:-
 * Tabs Held in Place by Screws
 * Twist Fit
 * Clips

https://github.com/bmsleight/lasercut

BMS
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Re: Lasercut

wolf
Have you ever considered a tapered dovetail? That is an old trick among woodworkers - takes a bit more skill to do it than plain finger joints. Laser cutters are advertised to be capable to tilt these days.
Wolf