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• Version 2 Arm Demo

  Nicholas Seward • 12/18/2017 at 22:39 • 4 comments

  It is way overtime for an update.  We have been working on it for months and have "wasted" tons of plastic.  We are now quickly conversion on an updated working prototype.  The video has some of the specifics of the updates.  More to come after the holiday break.

• Brain Fart

  Nicholas Seward • 05/01/2017 at 20:14 • 18 comments

  I have been furiously working to get out v0.2 that fixes many of the issues I found in v0.1 (the first prototype). I did a fair bit of design work in Autodesk Inventor because I am most comfortable with it. Once I felt good about the design, I moved over to Onshape and started remodeling the design but this time I made it highly parametric. The idea is that you can change a few parameters to make the parts suit your on hand components and personal goals. Everything was going well until I took a break to work on the kinematics of the new layout. I immediately found a core flaw that caused the whole redesign to fall apart like dominoes.

  THE PROBLEM

  Can you see it? The bottom belt can't do anything. I swear I thought about this being a problem and then figured a solution around it but here it is. I have a solution for this but I have to start from the ground up again. This design is very interdependent and all the parts have to work in concert. I actually like the new direction better but it has delayed me a week.

  I am obviously still working on the design and am not ready to publish step by step instructions for this project. However, in a show of good faith, I have uploaded my working prototype files and firmware. I can't stress enough that no one should build it directly. There are some easy things that could be fixed. (belt tensioners, fixed arm lengths, increased mechanical advantage, plastic reduction)

  Prototype Files

  Warning: I provide the files as is. Please don't build this version. If anyone decides to build a HELIOS from these files, they will be on their own. I am working furiously (with precious little free time) to finish v0.2. I will gladly provide support for v0.2 builders. Any time that I have to spend supporting a v0.1 build will take away the time I have to devote to v0.2.

• Adventures in Firmware

  Nicholas Seward • 04/24/2017 at 03:56 • 3 comments

  Alright. Lot's to cover here so let's dive in.

  This printer requires quite a special firmware package. I have been modifying Smoothieware but there are a lot of bells and whistles I had to add. Here is a short list.

  • Lazy arm mode switching (when you get to a place where the current arm mode can't go...switch but don't switch back until you are forced to.)
  • Machine coordinate moves when rapidly moving. (Say you move from one side of the build platform to the other. The quickest way is to swing the arm in an arc instead of going in a straight line.)
  • Codes for setting machine coordinates
  • Homing with a common end stop (accelerometer)
  • Incremental bed leveling (The bed is 5 times bigger than a normal 3D printer and you can reach most of it in 2 arm modes so the probing required is 10 more than typical. To combat that I have come up with a way to probe as you need where ever you need.)

  As of now, all of these items have been prototyped and put into firmware with the exception of the accelerometer probing. I have only done an offline proof of concept of the accelerometer probing but I am convinced it will work. Check out these videos for more details.

  It has been a wild quick ride. I will leave firmware for awhile to help let my brain recouperate. I am now on finalizing RepRap HELIOS v0.2. I hope to order parts tomorrow and have it working by the following week.
  

• Background

  Nicholas Seward • 04/22/2017 at 05:16 • 0 comments

  I put pen to paper just 19 days ago. It has progressed faster than I would have ever dreamed. I would have posted more here but I didn't even know about this until a few days ago.

  I teach at a residential high school in Arkansas for gifted students. I had one of my students work on a 1-arm SCARA mockup that has been bouncing around in my brain since the first time I saw a RepRap Morgan.

  The results where more than promising. We quickly started making plans to turn it into a 3D printer. My intention was to bring my student along on the design journey but I was a dog with a bone and I could now see what this could be. I cranked up AutoDesk Inventor and quickly cranked out this.

  I ordered all the vitamins and started printing all parts. I quickly got a functional arm together.

  I then set to work on making the firmware take care of the kinematics. Shortly thereafter, printing!
  

  I have taken it so much further than this but I think this is a good place to wrap up the first post.
  

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