I was showing off one of my CNC builds to a friend. When I told him I wrote a book on how to build the CNC step-by-step, he asked if I would be willing to demonstrate it at the DC Science and Engineering show.
I explained that the machine was not portable and it wasn’t designed to be moved. He said, “Could you design one that could be moved?”
I replied “sure.”
The new design had to be easily scalable from 12” x 12” to 144” x 60”. The gantry needed to be removable (for transporting). It had to be made from readily available parts so others could build it. It had to be extremely rigid so I could machine aluminum, and use very large routers and spindles.
I loaded up AutoCAD and began to work.
After a couple of weeks I had the design. The K
RMx02 was born.
It’s one thing to put your ideas down on paper. It’s another to model them in CAD. The biggest challenge is to bring the idea to fruition. CAD design is very forgiving. Software will let you place a bolt anywhere you wish, but if you can’t reach it with a wrench in the real world it has to be changed.
After two months, the first KRMx02 came to life.
This version of the KRMx02 has a 27” x 30” cutting area. The gantry can be slid off the rails for transport. The main machine is self contained so that it can be removed from the stand. While heavy, with help it could be transported. The design has high sides, which do two things. First, it helps keep debris off the rails. Second, it gives the gantry a very low center of gravity, which adds to its rigidity.
I had over-engineered the machine to the point that the gantry could easily be stretched to support a 5’ wide cutting area. There is no limit to the length, since it is supported every 12”.
Later, I found out that I would not be allowed to assemble or disassemble the machine at the show. So I decided to see how small I could make a machine to be transportable without disassembly.
Here is the machine I came up with:
I just finished it and it’s a dream. The cutting table is removable. With the table, the whole thing will fit through a 36” opening. Without the table, it will fit through a 26” opening. The area inside the stand is large enough to hold the dust vacuum and the computer with electronics. It has an 18” x 14” cutting area, which is great for demos.
If you want to build either of these machines, the books are available on the web site. Information and Gcode is also available for other CNC projects or upgrades.
Here are a few videos of the KRMx02 in action.
http://www.youtube.com/watch?v=DZ6wr3KC_ns]KRMx02 Cutting Pine - YouTube
http://www.youtube.com/watch?v=cRDYsnSxF08]Milling Aluminum - YouTube
http://www.youtube.com/watch?v=8LLNVskytLc]Cutting Sintra - YouTube