Rotational Feed Rate

[rcnewcomb]

Do any of you try to calculate a rotational feedrate? For example, on a flat workpiece you might have a feedrate of 2ips. Do any of you calculate and set the rotational feedrate in your cutting file such as....
VS,,,,FEEDRATE/(WRAP_DIAMETER*3.14159/360)

[myxpykalix]

Randall the rotational feed rate has more to do with the type of file you are creating and the toolpath strategy as opposed to an arbitrary feed rate you may assgn it.
For example this "wave pattern" video i made you see that the pattern dictates the feedrate.
http://www.youtube.com/watch?v=G9_Pk-lGauY

then you can see one where it looked more like a carving pattern being done (I don't even recall what i was testing there and disregard the spiral in the indexer, it was only there to offer perspective to the camera)
http://www.youtube.com/watch?v=nSkNv5W5tZM&NR=1

Then on the third one you see a different pattern created and the feedrate and rotation is dictated more by the pattern
http://www.youtube.com/watch?v=nSkNv5W5tZM&NR=1

There are also others who have posted videos where the round column in the indexer is carving a design in which you have just a basic raster pattern up and down the column and it just clicks over 1 degree or less per pass and has no rotation.

On the legacy manual mill we called the rotational feed rate the "Pitch"= distance carriage traveled in X for one revolution of 360 degrees.
That travel would vary depending on what gear we used (number of teeth in gear). That in combination with the type of routerbit (rope spiraling bit) and number of "starts" would determine the design you ended up with as in the last spiraling video.

I have not been able to adjust my feedrate on the indexer while a file is running.

So if the point of the question is can you manually adjust your feed rate in the file, i think you can, however depending on the type of file you are creating (3d onlay like grapevine pattern on column) you may not want to.
I hope I understood your question....

[bill.young]

Hey Randall,

There's some info in the ShopBot wiki that relates to the opposite side of that coin...setting your ShopBot speeds so that they're appropriate when you're using a lathe with fixed speeds. Not sure it will help at all but it's at:

http://shopbotwiki.com/index.php?title=CalcLatheSpeed

Bill