Introduction:
For my final project, I set out to design and build a plasma CNC table with software to run it. The problem turned out to be far more challenging than I had anticipated. It took more time and effort to resolve than expected. With the attempts to make the project look polished and professional only added to the complexity.
During the project I learned so much about fabrication and design. When it comes to steel work, I have always been a measure never cut twice type of guy. This project took a lot of precision and skill; many of the 3d prints would not have worked if off by more than 1 mill in any direction.
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Background Research:
The background research is the same as the project proposal. I spent a lot of time implementing the ideas and features of the paper. My table looks very similar to the one found in paper [1]. I spent a lot of my downtime trying to figure out how the CAD>CAM>CNC pipe line works. I am using the Ink scape for CAD> my Software for CAM and MY future CNC table for the CNC part. Paper 2,3 helped the CAM part along with 5+ youtube videos that are lost in my search history.
- https://www.researchgate.net/profile/Renann-Baldovino/publication/291336407_Development_of_a_Low-Cost_Controller_for_the_3-Axis_Computer_Numerically-Controlled_CNC_Plasma_Cutting_Machine/links/56a076f608ae21a564291f75/Development-of-a-Low-Cost-Controller-for-the-3-Axis-Computer-Numerically-Controlled-CNC-Plasma-Cutting-Machine.pdf
- https://rapidwelding.com/files/Improving%20Plasma%20Cut%20Quality.pdf
- https://dspace.lib.cranfield.ac.uk/server/api/core/bitstreams/7262fa07-79f4-4428-af27-3c724513154f/content
Process:
This project started with half a dozen sketches. After picking a design I like, I bought all the materials I Thought needed. While waiting for parts I used rhino to model plastic parts and write the software to run the table.
In my down time I wrote the software for this project. Green lines are travel lines, Red lines are inside curves and black lines are outside curves. This is important because inside lines should be clockwise and outside lines should be anti-clockwise
After getting a majority of the parts in, I redesigned, reworked my 3d models and started to assemble the table and control box.
Finding that parts were overlooked or did not fit like intended, I ordered and changed plans. In the picture above you can see an aluminum plate. I was goto machine out the axis sled but the ball screw was unable to fit. The solution I came up with was these plastic axis sleds that could hold the Y axis.These plus the end caps are very interesting because they let the ball screw to set on top of the tracks stopping the BK/BF12 holder from twisting and moving back and forth.
Making the Y axis was easier than I expected. I took the end caps and put them on the side and put a 40mm block to hold the axis together and it did not need any test prints and work on the first try.
Making the y axis looked like this
Finally I made the “table” part to place the x,y,z axis on.
Then I combined it all together.
Outcome:
As always I wish I had more time. It is not complete, and I have a laundry list of things to do before I am happy. As it sits I have made a really heavy paper weight for the time being. It moves when given simple commands with the manual pulse generator(mpg). But my software is broken in the slave axis. A slave axis is a duplicate of an axis in place of another. For instance, I can slave X to A and now have 2 stepper motors that do the work of X. This is great for when you have a heavy gantry. I will need to do more tests but I will need to wire up the x,y,z limit switches.
Overall I am happy with the progres I made.
Future Work:
Because this is a tool and not a toy I will continue working on this. I still have all the flex goals that I purpose in the original post. Like Plasma Torch Height controller and 2ndary Z axis. As the project stands I need to wire up the x,y,z limit switches and connect the Z axis. I will need my girlfriend to help me read the Chinese documentation of the cnc board I bought(because it differs in content when compared to the english one). I would like to get the slave axis working because when I try to do it in software things break badly.
Reflection:
This project was a massive undertaking for one person to do. I I found myself dedicating time to tasks, while not directly contributing to the final goal, added value in other ways. For instance adding cable ties and shielding this add nothing to the functionality but increases the future serviceability. Additionally Making the project portable required far more effort and planning than I initially anticipated, maybe adding 200% more time on to tasks. Lastly I want to say that shipping dates are recommendations.
All code is my github and STL are on my github:https://github.com/NicholasBacon/handandmachine_Final
STL:
Link to slides: