So, I’ve been collecting and assembling parts for a large CNC build I’ve wanted to do for years. My ultimate goal is to be able to cut parts out of entire 4’x8′ sheets of plywood, but for now, a simple 5’x5′ (well, 1500mm x 1500mm) machine will suffice.
Most of the parts put into this build are either components I’ve had laying around collecting dust, or they came out of the Gadget Shop’s OpenBuilds inventory. The only real “third-party” purchase was a set of aluminum plates, which are conveniently available on Ebay. I have to admit, those $150 plates are beautifully done, and I’m confident they’ll stand up to anything I plan to do with this machine.
The Controller is an old TinyG v6 that I once used in a ShapeOko v1 — an entry level CNC machine that has since been modified to operate as a 3D printer. I am running a heavily modified version of the TinyG firmware, and a heavily modified version of Repetier Host to exchange G-Code.
Why Repetier Host? Long story. At the time when I was using the TinyG on the ShapeOko, I noticed it would fail miserably due to all kinds of “seemingly-random” serial port data errors.
In other words, I had a bad case of line noise on that setup, and it was almost impossible to get a “clean” plain-text transmission over that serial connection without reducing the serial port’s speed ridiculously low. Synthetos (TinyG’s makers) seemed content with leaving the TinyG to use this “plain text” method of exchanging G-Code, thus I rolled up my sleeves and looked into options that would implement error-correction.
Since I was leaning toward converting the ShapeOko into a 3D printer anyway, I came across Repetier Host. What cinched the decision for me was the fact that Fedora Linux was adding support for Repetier Host. Looking under the hood, I found the source code to be a reasonably well-written solution — understandable and hackable enough for me to build up what I needed to cobble something together on my own.
As for this build, it’s about 90% complete — I’m waiting on a few more hardware components to arrive so I can button down the frame for good (mostly waiting on the cast 90-degree gussets for the gantry). Free time permitting, I hope to be calibrating the motion and making the first test cuts with a Dremel-like router by the weekend.
Yes, I know that dinky Dremel clone is under-powered. Remember – this is still being built from stuff I have laying around as a proof-of-concept. If I can cut simple parts out of plywood repeatably and accurately, I’m good.
Future plans for this machine are to convert it to a 3000mm x 1500mm frame (doubling and reinforcing the frame along its length); and maybe mount a real spindle on there -vs- an off-the-shelf router. The TinyG is more than capable of doing PWM (Pulse width modulation) to control spindle speed.