[bjmill81]

Ive been doing a lot of reading and I have some questions. I want to build 4x4 table and I was going to use the bladerunner AIO dragon.

1. Can I use 14 1/2 deg 20 pitch rack and pinion? I have alot of if it laying around the shop or should I get 20/20?

2. On the ratio for the pulleys i was going to go with 5:1 and can I go with that on both x and y axis?

3. Im going to use the dual drive on the y will the 300 oz motors work ok or should I go with the 620 oz motors?

Ill probably will have more questions as I go.. Thanks

[Torchhead]

Ive been doing a lot of reading and I have some questions. I want to build 4x4 table and I was going to use the bladerunner AIO dragon.

1. Can I use 14 1/2 deg 20 pitch rack and pinion? I have alot of if it laying around the shop or should I get 20/20?

You can but most builders use 20 deg PA. It tends to not climb out of the rack as easy (says meshed)

2. On the ratio for the pulleys i was going to go with 5:1 and can I go with that on both x and y axis?

Depends on the pinion diameter. 5:1 for the Dragon-Cut sytem is a little aggressive for pinions of 1" diameter and smaller. Your goal on a stepper system plasma cutter is to balance the R & P step up ration (PI times the DP of the Pinion) VS the step down ratio of the belt transmission. Thus a 1" pinion has a 3.1416 ratio and a 3:1 belt ratio gets you back the lost torque and resolution. (effective total ratio of 1:1)

Motors with the BladeRunners will spin about 600 RPM under a moderate load. Using a total ratio close to 1:1 you get about 600 IPM rapids and the torque of the motors.

3. Im going to use the dual drive on the y will the 300 oz motors work ok or should I go with the 620 oz motors?

You need to have good acceleration for plasma cutting. Acceleration is based on the mass (weight) of the gantry you are driving. The lighter you make the gantry, the better your acceleration numbers and the smaller the torque rating of the motors can be. The 300's work well for gantry weights in the sub-50lb range. For up to about 100 lbs or if you want to do some light duty routing, the twin 620's will give you better performance.

The advantage of driving both sides of the gantry with dual motors is you get twice the torque (acceleration/thrust) and the gantry can be less rigid so the weight can be lower. You reap a double benefit.

Ill probably will have more questions as I go.. Thanks

The BladerRunner AIO is easily expandable to 5 motor /driver operation so you can still have a dual drive gantry (hardware slaved) and use the 4th independent axis for rotary cutting. Our Rotary Wizard (Free) supports rotary plasma cutting.

TOM Caudle
www.CandCNC.com

[CNCPlasmaCutter]

Building a CNC Plasma Cutter. CNC plasma cutters are very high tech machines, use a new interface and all servo drive parts.