Homemade CNC with Scrap + Chinese parts || Objective: Milling Aluminium ||

[laranjas3]

Hello guys,
I already had build a 3D printer in 2013, I started to get bored with it, so I start to see some CNC videos on internet about CNC routers and I thanked: I can do it!!!

So I made a little research about homemade CNC's and I find out that I will need:
-Control system
-Stepper motors + drivers
-Transmission (belt's + pulley's)
-Ballscrews
-Linear rail/rods
-Metallic structure
-Spend little money as possible

So after that I went to my backyard and I found some 50*50mm steel tubes, perfect for the structure!
I went to the scrapyard and I found some aluminium tables with 15mm linear rails that looked perfect for X&Y axis and a linear structure with 20mm rod's that was good enough for Z axis.

I searched on ebay and found Nema 23 with 270oz-in with TB6560 driver + 24V power supply and mach 3 interface for a reasonable price.
The belt's and pulley's were ordered from www.bepltd.com, very nice guys, aluminium pulleys with 20&40 teeth for 1:2 ratio and HTD 3M belts, perfect for very small or no backlash.

After some time I found out my computer was not able to connect to Mach 3 interface via LPT1... So was time to search for USB solutions, and i found GRBL.
After that I ordered a One CNC V3 and an Arduino Uno from Ebay, perfect for the job.

After lots of welding, drilling, tappering, ect the cnc was running perfectly, almost squared!!!

At that time I explored the limits of the machine, and i find out that I abused with microsteps. The machine was too precise, too slow and with almost no torque.
Time to do some research:
-Calculation torque Vs microsteps & step/mm to achive resolution Excel link:
https://www.dropbox.com/s/lhz4ht3kh0...ixos.xlsx?dl=0

With this excel I understand why we should not abuse of microstepping, and why is important to choose a pretended resolution to you CNC machine.
An important factor is also driver voltage, TB6560 only are able to have a input voltage of 30V, this is a limitation to achieve max torque at higher stepper motor speed.

Spindle was a a very difficult choose since I don't really know what the machine can handle, so i went for 0.8kW+VFD chinese spindle water cooled from ebay, now I'm a bit regretted due collect 11 isto small(max 7mm mills).

Material:
CNC Structure & Parts
Steel tubes: Backyard
Aluminium parts: Bought on junkyard
Fixation: Welded steel tubes & screws

Linear rails: Came toghether with aluminium plates
Linear rails X&Y axis: 15mm wide
Linear rod Z axis: 20mm

Stepper motors: Nema 23 76mm 270oz-in (1.6N-m)
Driver: TB6560 + 24Vpower source
Control: One CNC V3 + arduino Uno + GRBL

Ballscrews: 1605 (Ø16mm & 5mm/rot)

Belts & Pulleys:
Ratio: 1:2 (20x40 teeth)
Belt: HTD 3M 9mm wide

Spindle & VFD
Power: 800W
RPM: 24000
Collet: ER11 (max 7mm)
Water cooled




So enough of talk and lets see the machine working!!



Next steps:
-Add endstops X,Y & Z
-Mill Aluminium Spindle brackets
-Protect rails and ballscrews from chips.
-Make a box for CNC (maybe soundproof)

I know this is not a perfect CNC, but for the first one I'm proud of it!

If you have any idea or improvement please share, Thanks.