rack and pinion queston

[dgalaxy]

if im running a 20 degree and a 20 pitch 1" pinion boston gear do you guys think ill be allright with this on a 4x4 plasma table

[Bill Clark]

yes

[JerryFlyGuy]

What speeds do you want to run?
What reduction do you plan to use?
What size stepper are you planning?
Is your power supply max rated for your stepper?

These are all things to take into concideration before a person can really answer your question. If you can fill in the blanks.. I can tell you if your the range or not.

Jerry

[dgalaxy]

between 8 inches a minute and up i have cutmaster 101 cutter 14 gauge is the smallest im going to cut
270 steppers 3 to 1 stealth gearheads 201 gecks
24v

[JerryFlyGuy]

Ok, and do you have the max numbers for the max thickness it will cut and or a speed at which it will cut it? Also, a weight of your x & y axis [ z included if its riding on the y axis ] and the z axis weight.
Are both your X and Y going to be driven the same way? [ie Rack and pinion w/ the same reduction]

I would venture to guess that you won't get 270 oz w/ only a 24v power supply but we can assum that it will. Any info on what kind of torque at say 300 rpm off these motors?

I should be able to grind out the 'close' numbers from this..

Jerry.

[JerryFlyGuy]

Sorry, missed two other parameters.

How accurate do you want this to be? Are you using 200 step motors? What micro Step level are you using on your drives?

Are you running only 1 motor on each axis?

I think that should be it...

Jerry

[dgalaxy]

i allready have the rack and pinion just making sure i will be happy with the results.or should i spend the money and get something else. im useing 2000 steps gecks gantry weighs oh i would say maybe 70lbs will be cutting awhole lot of 1/2 plate at approximate 38 ipm im useing iko linear slides no z axis .got a good deal on 4 of them. im thinking i might have $4900 in the whole table including plasma cutter. all axis driven the same way i have 2 of the rack and pinions of the 20/20 1" pinion everything is probably over kill but im worried about the rack and pinion making sure i will be happy with the resolution

[JerryFlyGuy]

"D", well it would seem that the steppers and the Rack combo is well suited.
The 20DP 20 tooth gear is rated at 79.2 [service rating of 1.0] in-lb's torque.

Max torque at gear 50.6 in-lb's [at stall]
force generated at stall torque is 101.25lbs [linear force]
force at 300 [Stepper] RPM [assuming 100 oz-in torque] would be 37.5
Resolution with 10uStep is 0.00052"/step
Max speed using Mach 3 [@25Khz] is 785 ipm
Accelleration [ 0-40 ipm- assume an average between stall and 300 rpm torque] is 44.4"/S^2
Time from 0 to 40ipm is 0.01 seconds.

These numbers assume you will get 270 oz-in at stall, and 100 oz-in at 300 rpm. Forces are for 100% eff. we could easily assume 80% of these value's to be 'safe'.

The only weak link would possibly be your power supply. Other wise.. all should work pretty well.

Hope that helps..

Jerry.. [ nice to take a break from it all and do some 'fun' stuff ]

[dgalaxy]

thank you for putting all that work into it for me i really appreciate

John

[JerryFlyGuy]

It wasn't that much work... its just a spread sheet.. but I figure if a person is going to spend the $$.. you might as well make sure your doing it right [ at least to a certain extent], rather than just point and shoot and hope you hit the target. I'm working on my own rack/pinion style machine and I'll be darned if I spend $5000 on linear rails w/out knowing intimatly what my machine should be able to do etc...

Glad to be of help..

Jerry [I guess I've spent to many years designing stuff for work,to ever "point and shoot" again...]