4 Axis GPU-CNC
I am now converting a mill head (taken from my lathe
Updated photo - had to build a new case and earthing to stop noise mucking up axis positions.
Notes on building a CNC machine
TODO
Set backlash: http://www.cncexpo.com/MeasuringBacklash.aspx
Controller
Was: 4 Axis CNC kit http://www.techlf.com/cnc4bu_kit.php3
Now moving to http://www.planet-cnc.com/
CNC USB controller software license
CNC USB controller Mk2 (9 Axis)
Connectors for CNC USB controller
MotorDriver 2.5A x 4
Mill Head
From Lathe
Drilling Capacity = 13mm
End Mill Capacity = 13mm
Face Mill Capacity = 50mm
Spindle Taper = MT2
Spindle Stroke = 50mm
Head Tilt = +/- 90 degrees
Number of Spindle Speeds = variable
Range of Spendle Speeds = 50~2250RPM
T-Slot Size = 8mm
Motor = 500W, 1Ph, 230V
Hand Wheel Graduation 1mm (= 1mm x 50 per revolution = 50mm per revolution)
Stepper motors
1.8 deg. (200 steps per revolution)
bipolar
4 wires
3 Amp / Phase
1.8 Nm
Nema 23
shaft 6.2mm d
Compound Table
From HAFCO
Table Size 155 x 470mm
Longitudinal Travel 290mm (limited to 240mm due to bits in the way)
Cross Travel 177mm (limited to 110mm due to bits in the way)
Tee Slots 2 x 1/2"
Height 130mm (travel from set position 46mm)
Hand Wheel Graduation 0.001" (= 0.0254mm x 100 per revolution = 2.54mm per revolution)
Weight (nett) 28kg
Timing Pulley config
X = x10 (Stepper) connected to x20 (hand wheel): 1 revolution = 2.54mm/2 = 1.27mm
Y = x10 (Stepper) connected to x20 (hand wheel): 1 revolution = 2.54mm/2 = 1.27mm
Z = x10 (Stepper) connected to X30 (hand wheel): 1 revolution = 50mm/3 = 16.666667mm
Purchased
T5 - 10 Tooth - 10mm Timing Belt Pulley x 4
T5 - 20 Tooth - 10mm Timing Belt Pulley x 4
T5 - 30 Tooth - 10mm Timing Belt Pulley x 1
T5 - 50 Tooth - 10mm Timing Belt x 2
T5 - 80 Tooth - 10mm Timing Belt x 2
T5 - 60 Tooth - 10mm Timing Belt x 1
Resulting Axis Config
X = 1.27mm(revolution) / 200(steps) = 0.00635 per step = 157.48 per mm
Y = 1.27mm(revolution) / 200(steps) = 0.00635 per step = 157.48 per mm
Z = 16.666667mm(revolution) / 200(steps) = 0.083333 per step = (12 per mm x16 microsteps) = 192.00 per mm