XL pulley 4 axis cutting

[ArtF]

Hi Don:

  The end radius wont be taken into account. In tangental shaving the radius at the
end is not material to the algorithm. The algorithm tries to align tangental points on a curve
to the vertical axis of the tool ( so only the edges). This works well in involutes. While never
planned for pulleys it turns out they do often work as well, but its hit or miss until it simulates well.
It really depends on the pulley type. If the root walls are a tangent to the center it tends to work
ok, but in some shapes it simply gets as close as it can.

  The algorithm in 4th axis is actually just trying to figure out how best to place the tool
at various steps along the way without hitting the stl 3d model of the tooth.

  Thats not to say a radius on a tool wont matter, even in involute cutting it still will make the
root more rounded in its trochoidal root area. But all cutting will really be attempted
at the bottom edge of the tool  on each step,unless "Maintain depth" is checked, in that case all cutting
will be attempted on the side edge of the tool so the tool will be kept lower.

  With pulleys I usually advise using a shaped cutter to the dxf shape if its a small
pulley, or failing that to try to make your settings so a slow run in the sim looks safe
and as close to pulley tooth shape as you can get. The warnings wont mean much
in many pulley types.

Art

[Campgems]

Thanks for the reply Art.  I figured the bottom radius of the XL pulley isn't an issue as the belt will not get that low anyway, but the upper side to OD radius may be. I'm guessing that as the radius is only 0.024" , a couple licks on the sharp edge with a file would probably be good enough.

An involute type cutting wheel would be best, so I might just opt for that route.  Home made though.

Thanks again for the help and explanation.

Don

[ArtF]

Anytime,

  Luckily for me my pulleys are such that I can 3d print them. They can be a bit of a bitch
in 4th axis.

Art

[Campgems]

Art, I haven't jumped into the 3D printing pool yet.  Really don't have room in the shop, AKA garage, for one thing. It is almost an aerobic exercise getting from the door around to my machines and benches.  My 9 year old grand son was out there with me about a month ago and was impressed by the machines.  He pointed out my old 10x36 Jet lathe, "What's that grandpa"  I told him it was a lathe, you put some metal in the chuck and cut away what you don't want.  His response, "OH, like a 3D printer, but it takes things away, instead of putting them on.  Neat." I may have someone to inherit my shop.

A lot of my shop time is making parts to upgrade my existing machines.  I have a Taig CNC mill than started as an early Taig manual. A second Taig ball screw CNC mill, my old Jet lathe, a 14" Asian band saw, two Taig lathes, a Jewelers Lathe, and two gemstone faceting machines. Grinders sanders etc.  The XL pulley project is the result of my Ball screw Taig lathe, I wanted a more positive and higher speed spindle than the little 3C belting could provide. One thing leads to another and down the rabbit hole I go.  I have fun though and now that's the important thing.  Sure wish I had some one to clean the shop after a day of making chips though.

Don

[ArtF]

Don:

  :). I know something of rabbits and their holes as well.  I tend
to think the secret of eternal youth is contained deep within those burrrows.
( I havent come across it as yet. :) )

Art

[Campgems]

Art, I think it is the search, rather than the destination.  The longer we search, the younger we stay ;)  

Just wish I could remember the dead end holes I already searched.  :-\

Don