CNC machine improvements

I’ve really enjoyed this little CNC machine I bought earlier this year. It’s been a good learning experience and I’ve been able to make some things that I just couldn’t make using a 3D printer. CNC machines offer greater material choices and precision, but are also harder to use than 3D printers. It’s a whole different world compared to 3D printing.

I bought my machine for about $1200 (with shipping) off of ebay from a company in China. For that price I got a small 4 axis machine (3 axis plus rotary axis), ball screws for good precision, a controller box, and a couple of bits to get started. Hard to beat the price, and I expected some inadequacies in the product. I’ve been able to identify some not so good qualities in the machine and made improvements and enhancements which I’ll preview here.

Here’s a photo of the machine, post-enhancement. I’ve swapped out the spindle motor, leveled the table, and added a camera to allow me to make more precise parts. The camera is essential for lining up the work piece again after it has been moved, like when it’s flipped over to machine the back side. I also added a wireless MPG (manual pulse generator) for controlling the machine during setup and operation. That alone is a big improvement to the process and is well worth it.

improved-cnc-machineImproved CNC setup.

Naturally, the new spindle motor didn’t “just fit” onto the existing machine. It was off by a millimeter or so in motor diameter and also in a couple of the mounting holes. I chose to make a new mounting bracket for the motor using my 3D printer. The bracket is certainly not as strong as the machined aluminum one that came with the motor, but seems very adequate for this machine. Because of the larger size of the motor, I had to change the configuration a little for the motor mount, and I made a new cable chain on the 3D printer to route the wires for spindle motor power and USB camera connection. I added a new, dedicated bench power supply for the spindle motor which is a big improvement over the spindle motor speed control that came with the unit. Actually the spindle motor control that came with the unit as part of the controller was pretty cheesy and burned out twice. The motor wasn’t so good either, and sometimes made noise like the bearings were not very good, including a loud vibration in the motor whenever much of a lateral load was placed on it. It would squeal pretty loud.

It’s so much nicer to use this machine now. I’ve still got some learning to do and experience to gain. I’d hardly consider myself a machinist but at least I can make some things I didn’t have the means to make before by myself.

Here’s a picture of the machine in its original state.

basic-cnc

Original CNC machine configuration.

In upcoming articles I’ll provide a little more detail on these enhancements. Stay tuned!




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