Has anyone uses Linear motors, or linear steppers?

[Swiss]

Hi all,

I was just curious to know if anyone has used either linear brushless motors, or linear stepper motors in their projects? For examples these:

Linear brushless: http://www.aerotech.com/uk/products/...ar_motors.html
Linear stepper: http://www.acpd.co.uk/cobra-linear-steppers.html

I was just wondering if anyone had any comments of their usefulness for CNC.

thanks

Hugo

[Gizmot]

Originally Posted by Swiss Hi all, I was just curious to know if anyone has used either linear brushless motors, or linear stepper motors in their projects? For examples these: Linear brushless: http://www.aerotech.com/uk/products/...ar_motors.html Linear stepper: http://www.acpd.co.uk/cobra-linear-steppers.html I was just wondering if anyone had any comments of their usefulness for CNC. thanks Hugo

never heard of anybody

seems like the main problems are controlling the motor, cost and strong magnetic field.

[Swiss]

seems like the main problems are controlling the motor, cost and strong magnetic field

The motors are basically brushless motors, so a normal brushless motor driver can be used (I think).

Cost is certainly a big issue, as these motors are still quite expensive. But, being a home build, the price for the machine still comes in at a lot less than a similarly speced commercial machine.

I hadn't thought about the magnetic field though. Is the field a lot stronger with these motors? What problems might it cause?

Hugo

[Swiss]

I just spoke to the company that sells the linear motors. They say the motors are frequently used for CNC applications. They also supply drive electronics, so control isn't a problem. The only problem is the price. Alltogether, for 3 axes, two motors per axis, encoders, electronics and software, it comes to more than £10,000! *ouch* Still, that would make the whole machine less than we paid for our Emco 105.

Hugo

[Garfield2]

Yeah, I've got an old style one that I drove with my PICStep drivers a few years ago. It was quite strong but it would really only be suitable for very light engraving.

http://www.fromorbit.com/content/pic...linear-stepper

Alan.

[Gizmot]

Originally Posted by Swiss I just spoke to the company that sells the linear motors. They say the motors are frequently used for CNC applications. They also supply drive electronics, so control isn't a problem. The only problem is the price. Alltogether, for 3 axes, two motors per axis, encoders, electronics and software, it comes to more than £10,000! *ouch* Still, that would make the whole machine less than we paid for our Emco 105. Hugo

control is not a problem... if you have the money

Control may be a problem for cheap guys using EMC2...
Most linear motors use a scale or glass linear encoder, wich is kind of expensive.

What I would love to do is develop a GPS style feedback system that use a cheap TGV (the train) style of linear motor. Next step would be to start my own machine tool business and crush the competition

btw, do you have any specifications on that £10000 quotation?

[Swiss]

btw, do you have any specifications on that £10000 quotation?

It was for six BLMC-92 motors, four CP-30 amplifiers, three Renishaw 1um linear encoders, CNC Control software, firewire cables.

The motors are 65.9N continuous, and 263.7N peak. I would like to use two per axis.

Specs for the motors: http://www.aerotech.com/products/motors/blmcspecs.html
Specs for the amplifiers: http://www.aerotech.com/products/amps/nd.html
Specs for the encoders: http://www.renishaw.com/en/9802.aspx
Specs for the software: http://www.aerotech.com/products/con.../a3200smc.html

Hugo

[RICHARD ZASTROW]

Hugo, If you're into spending money, try this: http://calinear.com/products.htm

Dick Z

[Swiss]

http://calinear.com/products.htm

Holy moly. Those are some awesome looking motors, strong too. The only thing is that they are a bit massive. Still, I might get a quote to see how they compare to the Aerotech ones.

Hugo

[RICHARD ZASTROW]

Hugo, FYI look at http://www.advancedmotion.net/pdf/servo1.pdf

They combine hydro/pnuematic (gas spring?) with linear tube motor. Think of counter-balanced vertical (Z-axis) application.

Just another EXPEN$IVE idea.

Dick Z

[Swiss]

Richard,
those are really nice looking actuators. Actually, I think we met the guys from that company when we were building a VR chair a few years ago. I'm going to ask them for a quote too.

Just another EXPENSIVE idea.

I'm not just looking to spank loads of money. We don't have much. I'm trying to save my company money. Next time we buy a milling machine, I'd like to show them that they can have a better, more reliable and less expensive one if we assemble it ourselves, rather than buying one. These components seem expensive, but when you add it all together, it comes to less than the low end Emco we have now.

Hugo

[RICHARD ZASTROW]

Hugo, I was only trying to do the Disney "imagineering" thing. I know those are expensive items. What if you counter-acted or assisted less expensive electric devices with pneumatic cylinders?

I've done that by using rather small ballscrews/nuts and counter-balancing with air cylinders & remote air reservoirs. The system also prevented power-off falling of the rather heavy vertical axis. It's a little bit of a balancing act but it does work.

Another reason or motive besides cost is I want to use off-the shelf, readily available components so my client/customers can have a replacement part available in case of failure. They wouldn't appreciate waiting for a non-standard part while their production is shut down.

Dick Z