Need Help!- USING TIMING BELT FOR 4TH AXIS INSTEAD OF WORM GEAR

[heilcnc]

would using a timing belt instead of a worm gear work for a 4th axis
that way you would have no gear backlash iam thinking of using 1-15
tooth xl pulley 1-60 tooth xl pulley 1/4 step on the stepper to get
ratio of 1-4 that would give me .1125 deg. a step would that be good
enough?

[hoss2006]

Worked good enough for me for making timing pulleys and such.
Good for light duty work.
Hoss

[heilcnc]

would the .1125 degree resolution be good enough to do some 3d milling?
on small alum. parts say no bigger than "1.5 in dia.

[HimyKabibble]

Originally Posted by heilcnc would the .1125 degree resolution be good enough to do some 3d milling? on small alum. parts say no bigger than "1.5 in dia.

That is almost certainly below the accuracy and resolution of the rest of the machine at that diameter....

[escott76]

Originally Posted by heilcnc would the .1125 degree resolution be good enough to do some 3d milling? on small alum. parts say no bigger than "1.5 in dia.

Use math :
Sin(.1125) = X/0.75
You are solving for X which is the length of the side of the triangle that is on the outside of the circle .75 in radius.
I get .00147 and some which means that at the diameter you describe you can move approximately 1 thou with every step. Sounds like enough to me.

[hoss2006]

What driver are you running?
Is the microstepping adjustable?
Hoss

[hoss2006]

1/8 microstepping would give you .05625 deg/step or .0007363108 arc length on the 1.5 OD.
More than enough IMHO.
Hoss

[philbur]

The resolution may be OK but the torque available to resist cutting forces is greatly reduced. As always seems to be the case, nothing is for free.

Phil

[Khalid]

Just check the following blog
http://my-woodcarving.blogspot.com/

[JohnHaine]

A series of articles in the UK mag Model Engineer's Workshop recently described a CNC T&C grinder using a cascade of toothed belts to drive the cutter round from a stepper (to grind the flute teeth). By using more than one stage you can get a very high ratio, but the rigidity will be limited by the stretch in the final stage belt drive. Probably OK for grinding but maybe not for milling?

John.

[Bob Adams]

Here a site for my Timing Pulley Maker program.
www.cad2gcode.com/pulley
It also can be used for Indexing, to make any # sides.
Bob A
www.cad2gcode.com/freeprogram

[dgoddard]

Here is a recent 4th axis completed using timing belt. Works great.