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Snowflakey

Tennis Man

Here’s a thing I’m calling (for lack of a better name) “Snowflakey”. The idea came from the Kimotion Arts store on Shapeways.

Kimotion Arts

Kimotion Arts has these neat 3D printed ornaments with an object arranged in a circle to make a snowflake-like thing. I dig it, so I decided to dig into it.

Bad Man

The first thing I did was fire up Inkscape and draw a really simple figure. It’s terrible, really, but I did it in less time than it took Inkscape to launch on Mac OS X. I created an SVG file, and then exported it as a DXF file, making sure I converted all the line segments into straight lines first. (Of course there were no curves in this drawing, but if there were, I’d convert them!)

Bad Man Flake

Once I had my DXF file, it was easy to pull that into OpenSCAD, and place six of them in a circle with the following code.


objheight = 4;
objcenterspacing = 20;
objrotate = -70;

for (i = [0:5]) {
  rotate(i*360/6, [0,0,1])
    translate([0, objcenterspacing, 0])
      rotate([0, 0, objrotate]) 
        linear_extrude(height = objheight, center = true) 
          import( "figure.dxf" );
}

The code is not the greatest… in fact there is probably much room for improvement, but it’s the first thing I got working, so I ran with it. My idea for the 3 variables at the top were so you could easily tweak them for different art. Sadly, as you change objcenterspacing and objrotate, they affect each other, so it’s a lot of back and forth between those two values. I also could not find a way to assign a filename to a variable, so your DXF will need to be named “figure.dxf” or you’ll need to edit the import line.

Tennis Man

Since my drawing was so terrible I wanted to try something else, so what better than Land recreation symbols 27, better known as “Tennis Man” by most people.

Tennis Man Flake

A few quick edits and I had this nice Tennis Man Snowflake for that special ball smasher on your list… (Notice the canvas size of 25mm wide by 35mm high. You can do what you want, but the OpenSCAD code will be expecting something close to that. Otherwise you’ll just have to tweak the numbers even more.)

Blobby Man Flake

I decided to try once again to draw something. This one took a little longer than a minute, but turned out just as terrible as the first one I did. Still, maybe you like “Blobby Man” as a snowflake.

Ant Flake

How about ants? This one is interesting. Maybe spiders would have been a better choice. (And yes, I know I could probably do the entire “6 items rotated” thing right in Inkscape, but that wasn’t the goal here.)

Horse Flake

What about the old nag? No, I’m not taking about your mother-in-law (kidding!) but this fine old horse from OpenClipArt.org, where I get many of the SVG files I use. Export this as an STL file and you’re ready to print it on your RepRap!

If you’ve got an improvement to this OpenSCAD code, by all means, let me know. I’m still very much in the learning phase with OpenSCAD, so I do these things to learn, and because of that I’m open to any suggestions.

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Inkscape to OpenSCAD

Gear!

Oh yeah! You can totally draw gears in Inkscape… In fact “draw” isn’t even the right term, as you can “render” them using one of Inkscape’s extensions. Here’s a nice post about laser cutting some gears that explains it quite well.

Gear Rendered!

Normally for 3D printing I’d export something like this as a DXF file and extrude it into a 2.5 dimensional object, like I outlined here, but there is another way… by using the Inkscape to OpenSCAD converter! (Here’s a nice blog post about it as well.)

Gear in OpenSCAD

It may not generate code that’s easy to edit, but it’s fast, and seems to do the job, which is often exactly what you want. I’m also quite pleased that Inkscape is becoming such a valuable tool not just for 2D work, but for 3D work as well. I might consider teaching an Inkscape class at Milwaukee Makerspace once we get our classroom up and running.

3D Printed Plastic Gear

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Mold Making

I’ve been digging into OpenSCAD lately and managed to come across this Flickr photo with the most minimal of explanation of how to do a reverse object in OpenSCAD, but it was all I needed…

Space Invader SVG

I started with the SVG file of the classic Space Invader character, sized to the width and height I wanted, and then exported it from Inkscape as a DXF file.

Space Invader STL

Once we’ve got the DXF we can pull that into OpenSCAD and extrude it into a 2.5 dimensional object. (It might be 3 dimensional, but I’m not going to argue 2.5D versus 3D right now.)


linear_extrude(height = 10, center = false) import("spaceinvader.dxf");

After we compile the code we can then export our object as an STL file. We can then pull that STL file into OpenSCAD again for the next step…

Space Invader STL (reversed)


difference() {
	translate([40,42,2.5]){
		cube([90,70,14.5], center=true);
	}
	# import("spaceinvader.stl", center=true);
}

You’ll need to tweak those numbers of course, and as for the # at the start of the import line, that’s to show us the object even when we can’t see it, as it were… sort of. It’s an OpenSCAD trick I learned from Mark Finn at BarCampMilwaukee.

So now that we’ve got the object dropped into a block (at the proper height) we can then export it as an STL file, which could be cut on a CNC machine, or 3D printed.

Space Invader G-code

I’ve not yet attempted to 3D print this, and I’ve had not much luck in printing things that are water-tight. I might try getting some silicone to coat the piece which would make it water-tight, and food-safe.

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Laser. Cut. Files. (Part III)

NOTE: See the latest post on this subject: Laser. Cut. Files. (Part IV)

SVG file in Inkscape
SVG file in Inkscape

After my last post on the subject, Laser. Cut. Files. (Part II), I figured that I had something that worked… but then something came along that worked better!

Thanks to a comment from old pal Thomas Edwards on the Part II post:

Have you tried Inkscape Save as EPS, then Preview EPS to save PDF? (Inkscape Save as PDF might work as well, but I find Corel Draw gets messed up by fonts unless I start as EPS and then go to PDF)

I decided to give PDF files from Inkscape a try. They didn’t work. CorelDraw gets some crazy error trying to open PDF files I create in Inkscape on Mac OS X… but what did work was a two-step process!

Again, my goal is to do all of my design work on Mac OS X, typically using Inkscape, and then moving my files to the Laser Cutter PC running CorelDraw on Windows (yuk!)

PDF file in Preview
PDF file in Preview

So for now, my process is the following:

  1. Create vector art in Inkscape
  2. Save (original) file as an SVG
  3. Save (a copy of the file) as a PDF from Inkscape
  4. Open the PDF from Inkscape in Preview and Save as a PDF
  5. Copy the new PDF file to Laser Cutter PC
  6. Open a new document in CorelDraw and import PDF file

Save as a PDF (again!)
Save as a PDF (again!)

Windows and Linux users, your mileage may vary, and obviously you don’t have Preview.app, but on Mac OS X this process works for me. And as for the note in the comment from Thomas about fonts, I’d be sure to convert any fonts into outlines after I save my SVG file, but before I save my PDF file. (It’s an old print design trick.)

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Laser. Cut. Wood. (Part II)

Laser Cut Box

In our last adventure cutting wood we had success! And it was good… So I decided to try the awesome BoxMaker again and I’m pleased with the result as compared to the previous attempt.

Above you’ll see the template I created from BoxMaker with a light bulb on one of the faces. I got the original bulb from OpenClipArt and tweaked the SVG file in Inkscape until I was pleased with it. (I may still need to adjust a few of the thinner areas, but I definitely like it.)

Bulb Box

In the next image you can see the results of the cut. This is using 3mm Baltic Birch plywood, which I highly recommend for the 25 Watt Laser Cutter that Milwaukee Makerspace has.

There’s actually one extra piece in the lower center which you’ll notice has straight lines, and is not part of the box, but this is the interesting part…

One thing about using the laser cutter is determining what settings to use. For this cut I used 100% power with 3.2% speed. It takes a few passes to complete the cut (maybe 4 or 5) but it works. I found that at slower speeds there is a higher risk of flames (which are bad!) and you can char the wood a bit too much. I actually didn’t care about the charring as I will be painting this box, but if you want less charring, up the speed a little bit, and know that you will need more passes.

Burninator

Oh yeah, the interesting part! In the image above, I’ve highlighted two areas. In the bottom red rectangle you’ll see a lot more charring. This is due to the long straight line that the laser cutter follows when cutting. I noticed that the notched areas, with lots of small short lines, had much less flame, while the long continuous lines had a lot more flame. (It was still within an acceptable amount of flame, but this is why I didn’t want to go lower than 3.2% for the speed.)

So I’m definitely calling this one a success, if only due to the fact that I’m pretty certain I’ve got good settings to use when cutting 3mm Baltic Birch plywood.

Also, lasers are awesome!