Path Rules

[eccles]

Hi Les,
This is a re-post in a new thread. The question relates to path rules. In this instance its the "before end" rule. I'm using the same simple circle as described before in the "code snippets" post.
What I'm trying to do is to vary the feed rate near the end of the circle to see if it has any effect on divots.
Please excuse my ignorance but I am having difficulty with the relationship between the distance specified in the "before end" rule and the "include leadout" checkbox.
For example if I specify a leadout of 10mm in the tool operation and a "before end" distance in a path rule that is less than this (say 5mm) , apply the path rule to the tool operation and post it - the resultant g-code has the required change ( feed rate ) at 5mm before the end of the lead out - that sounds reasonable - I think that's what I asked it to do. Where it gets interesting is if I want the feed rate change to occur slightly before we get to the leadout (in the circle) say at 1mm before the leadout starts. So I set the "before end" distance to 11mm. If I do this change when I re-post nothing seems to happen. - there is no feed rate change in the g-code - either in the circle or in the leadout. Is this the expected behaviour? The result is the same whether or not I have the "include leadout" checkbox ticked in the path rule.
Further to this:
If I edit the tool operation to set the lead out to none and re-post then the expected feed rate change appears in the g-code in the circle.

The issue seems to be that if I want to change the feed rate near the end of the circle and the tool operation contains a leadout then the "include leadout" checkbox will only produce feed rate change (and not in the circle) if the "before end" distance is less than the length of the leadout. If I want the feed rate change to occur in the circle itself I have to remove the leadout from the tool operation. Is that not the purpose of the "include leadout" checkbox?

Apologies if this seems to be a bit of a ramble .

Attached is the job file for 30mm circle, 10mm leadout, before end distance 5mm, do not include leadout, feed rate 150%.

[Les Newell]

I just had a play with your job and I think you are getting confused by the 'on circles' rule, which has priority over the 'before end' rule. The rule with the lowest feed rate wins. If you disable the 'on circles' rule, the 'before end' rule should behaves as expected.

[mancavedweller]

Hi Les,

are these path rule priorities documented anywhere. Seen this catching people out a few times.

[Les Newell]

Priorities are pretty simple. For feed rates the rule with the lowest feed rate has the highest priority.

[mancavedweller]

Fantastic, thanks Les.

All this time I never knew that.

[eccles]

Hi Les,

Thanks for your attention and the clarification over the path rule priorities. I have gone back over my original post and can see where it may not be clear as to the behaviour that I am observing. I'll try again to describe the issue. Its a simple 30mm circle with a single tool operation. I have a rule set that (1) reduces the feed rate of circles smaller than 50mm to 60% and (2) has a "before end" rule that increases the feed rate to 150% and turns the "Torch_OFF" 10mm before the end. Both of these rules are selected. If I post this, the G-code would appear to show that this works - I can see evidence of the "Torch_OFF" and the feed rate change before the end of the circle. I have not run this on the table. (Torch_OFF is just a code used as a marker to identify when the before end rule is activated)

Points to note:
1. The initial tool operation has an arc lead-in and NO lead-out.
2. The " include lead-out" check box in the "before end rule" is not checked.

Observations:

1. If I edit the tool operation to now include a lead-out and then post it, the resultant g-code shows the "Torch_OFF" in the same position as in the previous example (in the circle) but there is no corresponding feed rate change.
2. If I then edit the "before end" rule to include the lead out (check box selected) and repost, the g-code shows the "Torch_OFF" command has moved relative to its previous position but is still within the circle but the feed rate change has not occurred. ( The lead-out length is less than the "before end" distance)
3. If I then make the lead-out length greater than the "before end" distance and repost then the "Torch_OFF" command and the feed rate change both occur in the lead-out. (Include lead-out still selected).

Does this help to clarify the situation?.