Re: XL pulley 4 axis cutting
Posted: Sat Sep 01, 2018 2:27 pm
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
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