Re: A Axis Feed Rate
Posted: Thu Aug 24, 2017 4:59 pm
Keith:
That is true, but it still does not address the question of what you should enter next to "Feedrate", to achieve a desired cutting feedrate across the surface of the cylinder.
Whether you have P2 = 8 or not, it is up to you to compute the surface distance (accounting for linear distance plus angular distance combined with cylinder diameter); determine how much time that move should take; then work back to decide either what combined feedrate to program (if P2 = 0), or what linear-only feedrate to program (if P2 = 8).
In no case that I know of can you program a combined X-A move, and just specify the inches per minute you want the cutter to travel over the surface of the cylinder.
In response to Rick's earlier question/comment about the operator's manual description of the F code:
The manual description is incomplete.
For linear axes, the programmed feedrate (F) is either inches per minute or millimeters per minute, depending on the default units and whether you have programmed a G20 or G21.
For rotary axes that have been set up in degrees (so that one unit of travel is one degree), the feedrate is in degrees per minute.
Although it is uncommon, it is entirely possible to set up a rotary axis in revolutions (so that one unit of travel is one revolution). In that case the feedrate on that axis would be in revolutions per minute.
That is true, but it still does not address the question of what you should enter next to "Feedrate", to achieve a desired cutting feedrate across the surface of the cylinder.
Whether you have P2 = 8 or not, it is up to you to compute the surface distance (accounting for linear distance plus angular distance combined with cylinder diameter); determine how much time that move should take; then work back to decide either what combined feedrate to program (if P2 = 0), or what linear-only feedrate to program (if P2 = 8).
In no case that I know of can you program a combined X-A move, and just specify the inches per minute you want the cutter to travel over the surface of the cylinder.
In response to Rick's earlier question/comment about the operator's manual description of the F code:
The manual description is incomplete.
For linear axes, the programmed feedrate (F) is either inches per minute or millimeters per minute, depending on the default units and whether you have programmed a G20 or G21.
For rotary axes that have been set up in degrees (so that one unit of travel is one degree), the feedrate is in degrees per minute.
Although it is uncommon, it is entirely possible to set up a rotary axis in revolutions (so that one unit of travel is one revolution). In that case the feedrate on that axis would be in revolutions per minute.