Autonomous robot to take on a "Ninja Warrior" style obstacle course
MOSTLY PRINTED CNC
During the Summer of 2017 I decided to build a Computer Numerical Controlled Machine. After some reasearch I settled on the Mostly Printed CNC (MPCNC) mostly due to the low cost and the DIY aspect of the project. The MPCNC is a DIY CNC machine that uses a large amount of 3D printed parts (Thingiverse). I settled on workspace size of about 24" x 24" x 4" which gave an overall size of about 34" x 34" x 11.5".
Once the machine was assembled I spent about two weeks running drawings to calibrate and make adjustments to the machine before attachingthe router I was going to use as a spindle. I had some problems with jittery lines when moving along the x and y axes at the same time. After a teardown, some sanding of the pipes and a few part replacements, I realized that my bearings were installed too tightly which was causing the rollers to jitter rather than move smoothly. Loosening the bolts on the gantry and the rollers fixed the problem.
To create 2D drawing using the MPCNC, I create vector drawings using Inkscape. I then use a program called Estlcam to create gcode to control the MPCNC. The gcode is then loaded into another program called Repetier which can control the MPCNC. I am in the process of learning Autodesk Fusion 360 since it appears to be able to do everything in a single program but I have not attempted a complete project with it yet.
CARD STORAGE BOX
Inspired by some great board game inserts made by companies like The Broken Token, I wanted to create a storage system for a card game known as Warhammer Conquest which consists of about 1800 cards in total. I measured out a stack of 100 cards and began rough dimensioning the storage box on paper. Once I had some rough dimensions and a plan, I began modeling in SOLIDWORKS. I tried to keep the design as simple as I could with four walls, a base and a sliding cover. I then added 3 full width rows for cards and a 4th narrower row for extras. I did a few test cuts on my MPCNC to make sure the corner joint tolerances would fit correctly and then began cutting all the pieces. The box is held together with some simple wood glue and is very heavy. In hindsight I should have added notches near the bottom to make the box easier to pick up. If you would like to make one yourself, visit the Thingiverse project page for the files.
Click here (1 MB) to see a full 3D render of the card box assembly.
TABLETOP GAMING TERRAIN
I wanted to create a simple but modular set of industrial wargaming terrain. I looked at existing terrain and took inspiration from old tabletop games like Necromunda. I sketched out some ideas and how I wanted things to fit and then began modeling in SOLIDWORKS. I quickly realized just how many pieces I was going to need to design just to make a simple building so I simplified my designs down further to create these simple industrial platform models with easily added ladders, walkways and barriers. I intended to design it for 3mm MDF but I was unable to locate any locally so I used 3mm hardboard instead. This worked reasonably well, but the hardboard is not nearly as rigid as I would like. Future designs will need to account for this, or I just need to switch to MDF. If you would like to make some terrain yourself , visit the Thingiverse project page for the files
Click here (3 MB) to see a full 3D render of the terrain assembly.
ENGRAVINGS AND PUZZLES
Puzzles are a good way to test the MPCNC's calibration and make adjustments due to the tight tolerances that are usually required. The square puzzle pictured below was somewhat of a challenge to get the scaling correct so that the grooves matched the thickness of the wood. I used a 1/16" endmill to make the corners tight enough that the pieces fit snugly together. There is a little bit of play in the slots but they are tight enough to keep the puzzle together.
The animal puzzle pictured below is based on an older french puzzle. I created a vector from some images of the puzzle and then created the border and base for the puzzle to sit in. This was a challenge to cut out mostly since I had to space the pieces out. Cutting them out together would have created too large of gaps between the pieces and would have ruined the effect of the tight fitting puzzle. Some pieces, such as the snake, were difficult to cut out because of the narrow tail. This was a good test for securing pieces to the worktable and making sure my plunge rates were low enough to not grab the workpiece too much causing it to pull away from the table. After this puzzle was complete, I switched to mostly using downcut endmills since they make holding the workpiece in place much easier and I am usually plunging slow enough that clearing chips out of the cut isn't an issue.
Nameplates and engravings are very simple on the MPCNC. Any lettering can easily be turned into a CNC gcode file the same as a regular vector drawing. I chose to cut out the inside of the pictured nameplate just to create a nice 3D effect. The project could have been completed quicker and easier with a simple outline cut.