Archive | Digital Fabrication RSS feed for this section

Etching Glass Using Vinyl Stencils

29 Apr

I’ve been using my vinyl cutter recently to create custom glass etchings.  Vinyl resists the acids in glass etching cream making it perfect for high resolution stenciling.  The cream I use is can be found here (I picked some up at a Michael’s craft store).  You’ll want to be careful and read the full Material Safety Data Sheet for armour etch.  You can etch most glass but not pyrex (Borosilicate).   The results are pretty neat:

Coaster with an etched crane

Coaster with an etched crane

To start the process, you’ll need to create a vinyl cut and apply it to your glass:

Applying the vinyl negative

Applying the vinyl negative

Now, put on your gloves (seriously) and paint on some etching cream.  I also use an exhaust fan in a nearby window for added safety:

Paint on your etching cream and wait

Paint on your etching cream and wait

After about 5 minutes, I rinse off the etching cream.  The MSDS mentions that baking soda can help neutralize some of the acids; you’ll want to flush everything with lots of water.  Here’s the final result:

Final result of vinyl resisted glass etch

Final result of vinyl resisted glass etch

More photos via flickr: http://flic.kr/s/aHsjz5247h

Advertisements

Kinect + Blender 3D Scene Reconstruction

7 Apr

One of my current projects is to find a cheap and accurate way to 3D scan faces for the creation of custom coins and memorabilia;  mostly, I want my face on a 3D printable coin which can then be cast more cheaply in metal.  I had the opportunity to borrow a Microsoft Kinect which has 2 cameras and a structured light infrared laser projector.  One camera captures the infrared laser grid as projected into the room and constructs a depth map in realtime of the entire view.  The other camera captures visible light e.g. normal images and video.  I used the kinect to capture images and depth maps and reconstructed the scene in 3D using blender.  To dump the data, I used libfreenect‘s ‘record’ program, part of the OpenKinect project.

Here’s is a camera panning animation of the result created in blender using a displacement modifier on a heavily subdivided plane:

This is the unedited depth map that I took from the ‘record’ program output:

Kinect depth map produced by libfreenect's record utility

Kinect depth map produced by libfreenect's record utility

I had to scale and move the corresponding image texture to fit the geometry properly.  This is partly due to the slight distance between the cameras.  Here is the slightly altered texture image captured by the kinect:

Kinect image captured using libfreenect's record utility and slightly edited in gimp to align

Kinect image captured using libfreenect's record utility and slightly edited in gimp to align

This is the depth data as determined by blender’s ambient occlusion rendering:

Blender render showing depth via ambient occlusion

Blender render showing depth via ambient occlusion

I will soon compare these results to the free version of DAVID-laserscanner.  I’m currently waiting on the arrival of a very cheap laser line module ($2.50 to be exact) that will be used in conjunction with a high-def camera as input to the DAVID laserscanning software.  Stay tuned.

UPDATE: I’ve attached the .blend file for exploring in blender.  Textures are embedded.  Blender 2.56 Beta or later is recommended.

The Open Dream Journal Clip

1 Apr

I have wanted to design a simple notebook clip with an LED light for use on a dream journal for quite some time now.  Writing down dreams at night is difficult without a very convenient light source.  Now with access to a MakerBot 3D printer at sprout studios, I’ve released an open dream clip design on thingiverse, an online database of freely available and printable 3D models.  My design uses an LED and CR2032 battery, components commonly available at hackerspaces that would have 3D printers (and radioshack, although the parts are cheaper online through sites like digikey and mouser).

Here is the dream journal clip in action:

Dream Journal Clip with a white LED

Dream Journal Clip with a white LED

The first revision is pretty rough and we had to use tape on it to make it work:

Dream Journal Clip with a red LED

Dream Journal Clip with a red LED

Here is the MakerBot that Jimmie Rodgers kindly tuned and used to print the first test:

MakerBot at Sprout

MakerBot at Sprout

Planned improvements include:

  • using less plastic
  • making a larger hole for seating the LED
  • making a larger and deeper battery slot
  • adding a plastic tab to hold the battery in place (instead of tape)

Download the source files for the open dream clip on thingiverse and keep an eye out for  improvements shortly.

Hawaiian Sweet Bread with Laser Cut Flour Stamp

10 Feb

I’ve been working on a technique to use flour to stamp breads with laser cut designs and  have finally found a technique that works acceptably well for intricate patterns.  The breads below were made with this Hawaiian Sweet Bread recipe.  Here is the result after baking:

Finished Loaves with Flower of Life Flour Stamps

Finished Loaves with Flower of Life Flour Stamps

The pattern I chose is called the Flower of Life.  It is a six-fold symmetry made with overlapping circles.  Here is a video of the cardboard stamp being cut:

Once you have a cardboard stamp, you can moisten it with water to curve it slightly to fit the loaves.  I did this by using a rubber band placed around the pattern and a can of corn meal.  About 10 minutes before baking, while the oven is preheating, use a spray bottle with water to wet both the slightly curved pattern and the bread.  Shake flour over the wet side of the laser cut cardboard pattern.  Apply the pattern flour side down and press gently.  Here is a picture of the flour coated wet cardboard being applied to the moistened bread.

Flour stamp being applied to a bread

Flour stamp being applied to a bread

If you’re careful, it should look like this before putting it in the oven:

Bread Stamped with Flour Ready for Baking

Bread Stamped with Flour Ready for Baking

I’ve heard that rice flour mixed with normal flour improves the outcome.  You can also create these patterns with an X-acto knife in cardboard to achieve the same effect.  Have fun tagging your loaves of bread!