Gear cutting

[John S]

What I have been playing with.

Art Fenerty, the guy who originally wrote Mach3 before his retirement has come out of retirement to write a gear cutting program.

In typical Art fashion he's gone over the top doing eccentric gears 4 bar linkages etc, I have tried to get him back on the straight and narrow to do accurate spur gears.

the whole program was done to cut gears in the flat, router style and limited to thin gears that a vertical tool could reach and fit in.

Art has also added spur gears cut from a vertical cutter using a 4th axis.

Now he's the good bit, instead of using an expensive form cutter, of which you need 8 just to do one range of gears he has got the program to use a conventional off the shelf end mill costing, in my case, all of £2.99 [ less VAT ]

Watch this video of cutting a 45 degree helical gear with just a 3mm cutter.

http://www.youtube.com/watch?v=OI8f6Lrwx00

It first off cuts a slot out equal to the root of the tooth then moves in Y, offsets the rotary table to match and planes a face, it does this 10 times on each face to form the involute face.
Watch the video at 2 minutes in to 3:10 minutes and you will see this step over.

Also does spur gears. I did two 14 teeth gears and put them on pins at the correct centre distance and they run fine.
I then did two more blanks, exactly the same size and modified the tooth shape to cut 13 on one and 15 on the other.



These gears will chop and change onto any pins and run in any order.

More later if there is any interest.
Oh the program, it's called Gearotic and can be found at http://www.gearotic.com

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