having a problem with one of the path rules (on inside corners).
I drew a shape in cad to have two 45 degree angles, a 90 degree angle, an angle less than 45 degrees, and an angle greater than 90 degrees.
I also gave the shape perpendicular/90 degree leadin/leadout.
I created a rule On Inside Corners tighter than 50 degrees, expecting the rule to be applied to the two 45 degree inside corners and the tightest inside corner.
However, the rule is being applied to ALL inside corners plus the perpendicular leadin and leadout.
Is this a bug or something I’m missing. Job file attached.
In this case ‘inside’ and ‘outside’ are probably a little confusing. An outside corner is any corner where the cutter has to roll around the outside of a corner. An inside corner is where the cutter is going into a corner and has to make a sudden change of direction. In your example all of the inside corners are triggering a rule.
If you are cutting outside a shape the names make a bit more sense.
So an inside corner is any corner less than 180 degrees. This causes a sharp change in direction of the tool.
On the contrary an outside corner is any angle greater than 180 degrees and therefore the tool rolls around the corner. And therefore on an “inside offset” cut (as my drawing is), we can have both inside and outside corners.
I seen the “roll around the corner” thing yesterday when playing with the “On Arcs” rule and the rule was also applied to outside corners because the actual tool path was an arc going around the outside corners. On a side note regarding that, would it not be a good idea to disable the “On Arcs” rule being applied to outside corners, or at least have a tickbox option to enable/disable it ? I initially thought it was a bug when corners had the rule applied too.
Getting back to my “On Inside Corners” issue, all of the corners in my drawing are less than 180 degrees and therefore inside corners. So with a “Less than” setting of 50 degrees, shouldn’t the rule still only be applied to inside corners less than that angle. I mean is the overall meaning of the rule:
“On inside corners that have an angle less than 50 degrees” ??
Yes, that’s correct. However it is better to think of a straight line as 0 degrees, an outside corner is a positive angle and an inside corner is a negative angle. We are after all interested by how sharply the cutter has to deviate from a straight line.
On a side note regarding that, would it not be a good idea to disable the “On Arcs” rule being applied to outside corners, or at least have a tickbox option to enable/disable it ? I initially thought it was a bug when corners had the rule applied too.
I’m not sure. The corners in that case are arcs. Is there a situation where this would be a problem?
Getting back to my “On Inside Corners” issue, all of the corners in my drawing are less than 180 degrees and therefore inside corners. So with a “Less than” setting of 50 degrees, shouldn’t the rule still only be applied to inside corners less than that angle. I mean is the overall meaning of the rule:
“On inside corners that have an angle less than 50 degrees” ??
The angle is how much the corner deviates from a straight line.
Aah so that’s how it works, thanks very much Les, I would never have guessed that. This info is getting archived.
Regarding the “On Arcs” rule being applied to outside corners, if say I had a 270 degree small arc in my drawing with internal kerf offset and I wanted to apply an On Arcs cut rule to that arc only. Let’s say I wanted to turn THC off 5mm before the start of the arc and slow down feedrate 1mm before the start of the arc, then turn THC back on and put feedrate back to normal at the end of the arc.
I then find every outside corner has this rule applied and the feedrate slowdown affects the cuts on every outside corners, something I definitely would not want. It would be every outside corner because if the kerf width was say 2mm then taking into account the kerf offset from the drawing line, there’d be arcs 1mm in radius around the corners.
Also I can see many less knowledgeable users not understanding why the rule is being applied on corners, and think it’s a bug. After all why is an arc rule being applied to corners. I myself thought it was a bug 2 days ago until I turned off the kerf width view and seen the tool path as an arc around the corner. Yes technically it is correct, but many users will not be thinking (or understand) about arcs in the tool path, their concern will be arcs in the drawing.
And in any case, we have a rule dedicated to outside corners.
Perhaps a simple solution would be an option tickbox in the On Arc dialogue to enable/disable the rule being applied to outside corners too.
I could add a ‘exclude corner arcs’ check box. That way older rule sets would still behave the same way as they always did until you select that check box.
any rough idea on when you might get that tick box added. I have a big cut coming up where I have bend relief arcs and I wish to slow the feedrate at those arcs but don’t want the rule being applied on any outside corners.
