newbe questions

[Cecil]

This is my first try.I like what I read about xylotex controller.
My question is: my machine weight is 62.5 lbs,moves very easly
on roller tracks,using timing belts for power transfer . Our desired speed is 0 to 20 ipm.
what inch oz. stepper motors would you try , that could handle the enertia when making directional changes ? and would the xylotex controller be ok for this kind of application ?

[balsaman]

Hi,

Welcome to cnczone. I have a couple questions for you. What weighs 62 lbs, the whole machine? Just the gantry? You say you are using timing belts, is that to couple the motor to the leadscrew, or is a timing belt used to move the whole gantry?

If it's the whole gantry, with no leadscrews, you will need a gearbox on the stepper. You want to set it up so one step of the stepper moves the machine between .00025 and .0005" I would say. If you can get it setup that way, then I would think 100 oz motors will move it along at 20" just fine with the xylotex board, probably faster.

What do you plan to cut?

Eric

[Cecil]

thanks balsaman for your response.yes the whole machine weights 62.5 lbs mounts on a dolly,moves in x and y only.on rails 14 ' long What it is ,is a home made sewing machine with a 31" throat. that we want to cnc it to sew patterns in king size quilts.We have hand made everything ourselves so want the
bells and whistles of cnc so you dont have to move it by hand.
Both X and Y will use a timing belt for power transfer. will use the timing belt and stepper like a rack and pinion.does this make more sence?does xylotex sell 5v and 12v power supplys for thier drivers?

[ger21]

He sells a 24V supply which is what you really should use. You can also find some good deals on 24V supplies on Ebay.

Gerry

[balsaman]

Like I said, you will need a gearbox on the steppers. You can't just put a pulley on them and expect them to move the machine around.

Eric

[tsalaf]

Cecil,

That's a very interesting project. Do you have pictures?

Steve

www.tac-pro.com

[CAMmando]

I think you could use 2 different size timing pulleys (If Im picturing this setup correctly). Motor to "pinion shaft and Pinion shaft to Drive belt.

The ratio of the belts could give you your reduction.

[Cecil]

original idea was to use timing belts running length of machine in x axis and y axis with stepper motor having a cog drive pulley with 2 idlers on smooth side of belt maintaining minimun of 10 teeth contact on drive cog/gear , What ever the proper name is ?Its a very clean enviorment it will be working in.Balsaman said to use gear box motors. thanks for the food for thought a mandral
stile reduction could be made to work ,I think .Cecil

[tsalaf]

Cecil,

I just had a look inside my dot matrix printer. It has a timing belt supported by a toothed wheel at each end with the print head attached to the centre of the belt. One toothed wheel has a gear reduction to the motor. This looks like what you are trying to do. You will probably need a belt on each side of the X axis connected by a jack shaft. The other issue would seem to be some sort of support to reduce belt sag when the carriage is at it’s extremes. Slides attached to the gantry with magnets and "left behind" at preset intervals to support the belt may work.

Steve

www.tac-pro.com

[Cecil]

tsalaf:
Thanks for the input. See" machine combo" pictures that I just posted under, "Home made CNC machines", in the photo gallery . this is a great site . click to enlarge the picture , you will see that there is a clean flat table surface under the machine at all times ( as long as it does'nt jump track ) which is'nt likely if we keep the speed down. plan to let the motion of the machine pick up the timing belt and the lay it back down as it moves. which is a little bit like your printer idea.or let the belt loop like you said.