Friday, August 30, 2013

How to import openscad model in autodesk inventor

I drew something in openscad and wanted to send it to my collaborators who use autodesk inventor (2013). I naively thought it would be easy, but it turned out to be a little weird. Inventor 2013 opens STL files, but it always adds or subtracts random things to the files I tried, so first you have to fix it up (using Inventor Fusion 2013).

Here's how I got it to work (I didn't figure any of this out, google told me):

  1. In openscad, export as .STL
  2. Open the .STL file in Inventor Fusion 2013. It should look correct.
  3. In Fusion, save as a .STL file
  4. Install the Inventor addin Mesh Enabler
  5. Open the .STL file (the new one from Fusion) in Inventor. It should look correct. Instead of drag and drop, I open from Inventor so I can set my units under 'options'.
  6. Right click on the part and select 'Convert to Base Feature'. Select output 'Solid/Surface' (cube) and check 'Delete Original'. Wait a bit.
  7. Now you can save as a .IPT file and you're done!

Sunday, August 25, 2013

fixing a toy cement truck with a 3D printer

I've been looking for an excuse to get familiar with openscad and a 3D printer I have access to. So I was happy when I thought of fixing my kid's broken toy truck. We bought a bag of vehicles from a second hand store and the cement mixer was missing the mixer barrel.
So I figured it would be the perfect project to make a new mixer barrel. I designed the barrel in openscad, and made it hollow to save on time and material. I uploaded the CAD files to thingiverse in case anyone ever wants to do something similar, and because their CAD pictures look great:
I printed the barrel in two pieces and added some marbles inside to jiggle around.

That's not the best picture, but it turned out great and actually spins!

I learned a lot about 3D printing, especially from many failed prints. Here are some of my tips:
  • slic3r
    • Occasionally I got errors when I imported an .stl file. Usually they were fixed by netfabb's online tool (or fixing my openscad source)
    • I originally assumed slic3r would pick the best print orientation, but it just prints from z=0 and up. So you need to design your .stl file accordingly.
    • Lots of helpful info here.
  • adhesion
    • I had lots of trouble with adhesion to the kapton when I first started. Sounds like the melted ABS in acetone slurry is the way to go, but I didn't try that.
    • I had good results when I flipped the plate over and printed on the bare glass, using hair spray to help stick. I removed the glass to clean with acetone (nail polish remover), then sprayed hair spray on it, clipped it back down and heated to print. 
  • spool
    • The spool kept getting bound up on almost every print. Usually because the plastic would get trapped on the inside and tighten up instead of unwinding. I didn't figure out how to fix this.
    • I did successfully restart a print that failed halfway through (instructions here).
  • leveling
    • I couldn't really tell anything from the bed calibration test print. It looked fine to me, but when I checked the level with the single piece of paper method, it seemed way off
  • air quality
    • I was surprised at how smelly the printer is. After a couple hours of sitting next to it, my lungs were not happy. If I ever need to use one again, I'll have to set up better ventilation.
I also had fun printing out different models from thingiverse:

Monday, February 4, 2013

Keurig disassembly pics

Based on this excellent step-by-step guide to disassembling a Keurig, I have added pictures of most steps. All text is copied straight from the forum post by 'switch998', just to make the pictures more clear. This post is just so I can link to the pics.
  • Remove the bottom plate. There are a few Philips screws holding the metal plate on. The grounding wires are riveted onto the metal plate, preventing complete removal of the plate.
  • You are now ready to remove the plastic frame. Locate the screws for this frame around the bottom edge of the unit. There is another screw by the drip tray, and another by the basin pump. Do not pull the frame yet.
  • The basin pump and basin LEDs must be removed now. Locate the 1 screw for the LED and the 2 screws for the mouth of the basin pump. These are located directly below the basin.
  • Pull the frame out and de-route the power cable (optional). Be careful of the basin pump, you will need to bend the tube connecting it to the pump. You may want to unscrew the pump.

  • Remove the 2 screws from the underside of the K-CUP arm. Open the K-CUP arm. Remove the holder.
  • Remove the 2 black screws located in front of the holder (inside bottom). The body piece will fall off, hold it up with your hand when unscrewing then pull it off.
  • Look directly above of those 2 black screws, you should see two more screws on the top of the K-CUP arm. Remove those screws and slide the body piece out from underneath the handle.
  • Remove the 2 screws securing the top cover to the frame of the unit. These are higher than the K-CUP arm's two screws. You only need to remove the top cover's two screws. Pull the top cover up from the gap, this will not remove it but it will loosen the clips for removal.
  • Flip the unit on its side again.
  • Get a flash light and look in the cavity where the water basin was, locate the clip securing the top cover of the unit to the case. It is located directly back of where you are looking, it is not on the side wall of the unit. Pry it back towards the back of the unit and push up. This requires a lot of force, you may want to use a long screwdriver or tiny crowbar.
  • Stand the unit up again.
  • While the unit is still on its side, pull up the top cover a bit more. Shine a flash light into the gap and locate another clip on the back side of the unit. Use a screwdriver to push and pry upwards on the clip. It should come loose. Do this for the next few clips as the come loose. Pull off the top cover.
  • Unscrew the two screws above the LCD. Unscrew the screw securing the back cover to the front panel on the other side of the unit. Slide the back cover down and pull it back to remove.
  • Your brewer is now fully disassembled. If i missed a step, please correct me, but i think everything is correct.