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The Aluminum Extruder, or Alu Extruder, is a hit!  There has been a few little changes — as is my MO, if I can Simplify it, I will.  This of course creates some confusion and underscores the need for good documentation.  I spent a few hours today trying some new experiments in showing exploded views and assemblies. Documentation is not always fun, but  I really enjoyed the process and wanted to document the documentation a bit. Meta, I know.  To some, this will bore you to tears, but others may get a kick.  I am not reinventing any wheels, just explaining some of the thoughts that went into the process.

The Alu extruder started as a big debate between Brian Roe and I about how we could make an extruder out of metal and improve upon the past designs and the stuff available on the web already.  As most designers, we hate to just use something someone has done – we have to improve it and change it to our liking.  There is no shortage of opinions between Brian and I, and we get impassioned from time to time but respect each other enough to give and take.

After settling on a set of requirements and hashing it out, Brian came back with a 3d model done in Inventor.  He’s a whiz at that stuff, and I am the newbie with a drop of Solidworks training and thousands of hours on Sketchup – but I wouldn’t call myself a pro at any of it.  Anyway, that is to say that I can’t open Inventor files since I don’t have the program and from the start we start doing the frustrating file dance.  I pretty much have to call him in, have him show me on his computer or we do a web conference and he walks me through a screencast.  In this case, he sent me an STL file to print, which is nice, but I still didn’t have anything I could use for documentation until the part was built.  Yes, Brian could have done the documentation, but I keep him on the major design stuff for now.

I insist on using free tools when at all possible.  Open source is my preference, since my desire is to enable young people and old to jump in. learn and create.  I absolutely despise money being a barrier to entry.  So I wanted to use sketchup to do some exploded views.  Importing an STL file into Sketchup eluded me for a while until it dawned on me to import it into Meshlab (open source) and then export the mesh as a .dae – a Collada file.  Collada is what Google Earth uses.  Is is a cool format that does beautiful renderings on a mac and is used in iBooks to great success.  I would love to know if it can be viewed on windows or the various flavors of phones and tablets out there.

I then took the .dae files and imported them into Sketchup.  Now I was at home and could do my exploded views for free.  I make every piece a “component” in Sketchup so I can collide them, spin them, and move them without fear of messing up the walls of the object.  I also utilize the 3D Warehouse to get search for hardware, motors, etc and save design time. (File > 3D Warehouse > Get Models… then import them right into your drawing with one click.  Often I cannot find everything I need so I copy screws, stretch them, modify them to fit my needs.  Its only for illustration, so I don’t mind that it is not perfect.  The desired outcome is to help people see how it fits together. I think the lines showing how it fits together is helpful, so I add those.  I did an exploded view and an assembled view for contrast.

At first, I was doing screenshots, which may look ok in this small size, but it looks terrible at full size.

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Then I was trying a 2d export, which looked a little better to me. See full size.

Alu Expolded-assembled2


Then I remembered I could view an exported .dae natively on my mac.  I was not only thrilled with how it looked, but as you scale it up and zoom in, it is pristine!  I tried exporting from Preview (the native image viewer for Mac) but it was really ugly, so I just took a screenshot.  I use the “Shift-Command-4” one that lets you draw a box. The texture and shading was way better than I expected.

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To add to the appeal even more, you can spin the whole thing around to see any view right in Preview.  Brilliant!

Exploded and Assembled Aluminum Extruder Collada Files you can view or import into Sketchup (Zip file)

As a side note, you can do some cool animations with Sketchup, too.  I find it a bit hard, but there are some plugins that give you a bit more control and you can even do an Exploded view that assembles itself step by step.  I did that for the first time with the Printrbot Wooden Extruder.  It was fun but time consuming.

As documentation gets more and more important, I am warming up to these exploded views.  I debate whether images with clear plain text is better than build videos — which should I do?!  Answer: all of them, I think.  Some wish for videos, some like pictures, and I personally really like these live 3D models that you can view from any angle.

So there it is – I think the next step is to get some help converting the DXF files I use for the various retro-mounts onto all of our past and present Printrbots.  They need converted to stls and imported into Sketchup to be able to show how all the various flavors of mounts go together.  If anyone wants to play, or just print their own mount parts – See the file linked below.  Beware that the dxf file will have lines not joined and all sorts of other idiosyncrasies… our workflow does not require them, so we get lazy.  If anyone is interested in making these printable YMMV!

All files listed here and created by me, Brook Drumm, and Printrbot staff are Creative License Share and Share Alike Attribution Non-Commercial.  So use them and share them but don’t sell them.

Alu Upgrade Plates.dxf

Creative Commons License
Printrbot Aluminum Extruder Upgrade Plates by Brook Drumm is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.