Pulley ratios of x carve

X-Carve
1

I’m interested in converting my x carve to ball screws. The Z Axis seems like 1:1 since it runs pulley to pulley but the X and Y have me scratching my head,
does anyone know the ratios of the Nema 23 GT2 Pulleys?

2

They are 20 tooth pulleys by default, this should get you going.

3

I’m sure somebody else more knowledgeable will chime in here, but isn’t it based on the belt pitch, number of pulley teeth and step angle (of motor)?

The lead screw calculator on this page may help:

4

Thanks,
I guess my next question would be… what is the default step angle for the X carve NEMA 23 motors? I am considering a geared 23 in-line with a IGUS Lead screw so Ill have to match the gear ratio + equivalent lead screw pitch to equal to the GT2-20 tooth belted.
Why geared? you ask- I’ thinking torque for doing aluminum more than wood.
Any experience or comments on this? I would love to hear input before buying gear.

5

I’m not an expert on this but my understanding is nema 23 motors have 200 steps per revolution so without micro stepping it should cover 200x 2mm (for GT2 belts). Than I believe you just need to divide by micro-stepping value gshield is set to.

As far as geared motion if I were you I would seriously consider using this solution:

They have all you need and prices are very reasonable in my opinion.

6

Another area of investigation you will require is a way to reduce the flex in the X and Z carriage.
Having the extra torque is nice, but reducing the flex will make more of an improvement.

Example, the Z axis can be flexed (lifted) by hand quite easily. This makes plunge cutting the weakest operation of an X-Carve.

How well does your machine handling cutting Aluminum and wood currently?

8

1.8 deg (200 steps per rev)

9

oh yes, I’ll be milling and cutting many heavy duty parts for the conversion. I’ve already replaced the single 20 X 20 rails with 20X 40, and sandwiched a 50mm x 4mm strip between the gantry rails.
Most of the ball screw/shaft sets are in the 4mm or 5mm per revolution, so ordering the right gear drive should a snap as soon as I understand what the factory xcarve distance per revolution is.

10

Any idea what the gshield driver micro stepping is?, the calculator needs that .
so here are the constants as I understand them:

  1. Belt pitch of stock gt2 belt = 2mm

  2. teeth =20

  3. motor step angle 1.8 deg steps
  4. Microstep
    20160218_183702.jpg1344×2384 700 KB

    20160218_183759.jpg1344×2390 793 KB

    20160218_183825.jpg4249×2390 2.06 MB
    ping = 1/16?
    my system upgrades so far=
  5. all Cal Test silicone wiring to prevent any worries of fatigue- about $120
  6. 80/20 corner brackets about $50
  7. flexible shielding for the motor wires to prevent interference.
  8. 4mm gantry reinforcement plate. and lots of time with machine squares to get everything right.
12

Thank you for the info,
Can the driver microstepping be changed to different values? If so then it would be far easier to work out equivalent values.

13

Been a while since I updated this.
I’m getting ready to buy Ball screw and dual linear ball slides comments welcome.

  1. (factory X-Carve) Z Axis= 2mm/ rev - replace with 2mm/Rev Ball Screw with motor directly inline w/coupler-
    A. I’m going to increase the head space up to about 200mm for working clearance.
    B. 12mm Ball Screw 20mm Linear shafts- then improve mounting for my router- convert to something stronger later.

  • X Axis is 40mm/rev (stock)- 2mm x 40 teeth x 1.8 motor step Angle and 1/8 micro-step-
    A. The calculator shows a Lead Screw with 10mm/rev and inline 4:1 NEMA 23 Gear motor is equivalent

  • Y axis travel equals 40mm/rev same set-up as X
    Can anyone confirm?
    I really prefer to set this up with Motors directly in-line with the ball screws.