[Danny1978]

Danny1978
Registered

Join Date
Jul 2013
Posts
0
Downloads
0
Uploads
0
In need of help rack and pinion servo design
Hello all I'm currently in the process of designing myself a heavy router the problem I have is I'm unsure of what size motors and reduction I need for a rack and pinion. I have myself a 20amp servo system from low cost cnc retrofits. They came with the ametek 600oz servo motors max 1000rpm, I'm not that confident in all he calculations needed to achieve what I'm wanting out of this machine, hopefully some one can help with these bits of info I can give. I have estimated the gantry ( y axis ) to weigh around the 200/250 pound mark ,it will run on 25 mm hiwin rails as will the x and z axis. I plan to run module 2 rack and pinion on the y and x axis and a 20 mm 5 mm pitch ballscrew on the z axis. I'm not looking at a lightening fast machine I want something that is reasonably quick around the 10,000 to 20,000mm a minute rapids but really want something with reasonable accuracy and plenty of grunt as i want to cut a fair bit of aluminium,I just don't think these motors are up to the task,especially when I want to run the gantry from only one motor through a reduction to a drive shaft which connects to the racks on either side. This problem has stopped me in my tracks,I'm looking for some advise on this from someone with experience ,I have searched cnczone for the answers I need but a lot of it doesn't make sense to me. I'm very keen to get this build underway but don't want to pump money into guessing motors and reductions. Any help would be greatly appreciated,I am quite new to this as you could probably tell with the lack of knowledge .thanks Danny

[ahren]

Can you provide a link to the motors you purchased? The only 600 oz-in motors I see on their site are stepper motors. If you have steppers, our rack and pinion drives are pretty well optimized for stepper motors. If you have servos, you may want a larger reduction due to the difference in torque characteristics of servos vs. steppers.

Best regards,

Ahren
CNCRouterParts

[Danny1978]

Hi Ahren the motors I have got they don't sell anymore,they are 38volt ametek motors not much info on them that I can find .what I no is they are 38 volt 12 amp 600oz/in and around 1000rpm and they are servo.keen for some advice on weather a 3:1 or 4:1 reduction will get the gantry moving at decent speed and be able to have the power to cut thanks.Danny

[ahren]

Danny,

It's a little tough to say without seeing a power curve, but I'm guessing these will at least move the system with our standard 3:1 reduction. 1000 RPM isn't that fast for a servo -- some of our steppers can get up to around this speed.

Best regards,

Ahren
CNCRouterParts