Looking for feedback on my DIY CNC for steel milling
Hi
I'd love to get feedback on this CNC mill that I designed or advice before I commit to actually building it.
I designed this CNC with the following specs in mind:
- It needs to be able to mill metals, primarily aluminum and steel.
- Work envelope of 180x150x150 XYZ.
- Ability to produce parts with +-0,03 mm accuracy.
- Reasonable part production speed for a hobbyist.
The hardware I plan on using:
- Chinese BT30 spindle cartridge with ATC with 1:2 and 2:1 reduction
- 750W 3000 RPM servomotor with absolute encoder to drive the spindle
- NEMA23 steppermotors with closed loop encoder
- Chinese SFU1605 ballscrews, nuts, bearings
- Chinese HGR20 rails and carts
- Gasspring as counterweight for the Z-axis
The frame is built entirely out of S235 steel, with everything welded together as much as possible. Ill be stress relieving the frame it heat treating it as well. Instead of filling the frame with epoxy granite I'm planning on filling the frame with sand to dampen vibrations and add weight. I'll also be scraping all the mounting points for the rails and the carts flat and on the same plane.
The base is made out of 3x 80x80x3 steel tubing with 8 mm thick metal plates on top. The platform on the Y-axis that serves as the base for the X-axis is a 6 mm thick steel plate with 20x20 steel for where the rails will be mounted.
The bed is a 20 mm thick steel plate with the work envelope marked in yellow and will be scraped flat as well.
The column is made out of two pieces of 150x50x3 mm steel tubing and 1 piece of 100x50x3 mm steel tubing, welded together and reinforced by 6 mm plates on the backside and the left and right side with bolts.
The column is welded to a 10 mm thick plate and will be squared up to the X and Y axis using JB weld metal epoxy and jackscrews. The spindle will also be trammed to the bed this way.
The spindle overhang is about 215 mm from the column, and this construction is made out of 6 mm steel plates with a 10 mm thick platform for the Z carts.
I hope that covers it but let me know if you would like clarification on anything!
Would love to hear you guys' thoughts and all advice and feedback is appreciated!