Thursday, September 17, 2009

Steppers and microstepping controllers that will be used

Here are the details of the micro stepping controllers to be used on Big Bertha.

• Constant Current
• PWM Control
• 18-50V DC
• 0.54A to 4.2A/Phase (Peak) in 8 steps
• 2 to 128 Microsteps (400 to 25600 Steps/Rev) Max.
• Automatic Half Current Option
• All Logic Inputs Isolated
• Low Noise
• Low Heat Output
• Single Clock (Step/Direction) or Dual Clock (CW/CCW) Option
• Full Protection for:
  • Over Voltage
  • Over Current
  • Wrong Phase Wiring

Here are the details of the steppers

Y and Z steppers Spec
  • 10mm drive shaft
  • 1.8 Degrees a step
  • 311 ounce inch
  • 2.5 Amps a phase
  • 3 ohms a phase
X stepper spec
  • 10mm drive shaft
  • 1.8 Degrees a step
  • 495 ounce inch
  • 4.2 Amps a phase
  • 0.8 ohms a phase

Tuesday, September 15, 2009

Big Bertha the beginning

Big Bertha begins with Legs made from the B&Q CLS timber 38mm x 68 mm (low cost @ 1.94 for 2.4 M) Big Bertha will have a work area of 600mm x 1200mm or 4' x 2' feet

Bed will be supported by two 5' sash cramps the Y axis gantry held together with 10mm threaded bar sliding on 20mm hardened rails with pukka CNC linear bearings with the z axis supported on 16mm more hardened rails with CNC linear bearings.

I ordered some 1/2 " industrial roller chain from the USA with the idea for driving the x axis on chain as its 1.4m long thinking threaded rod would flex when turned at speed unless it was really thick.. I may revert back to a drive shaft if chain is not as good as I anticipate.