[magicniner]

I'm trying to generate paths for a part from another forum, I though it looked like a good excercise to work on in conjunction with some of Al's tutorials.
The part is a bar with a series of shallow slots in the upper surface, if I leave the end lines of the slots solid the paths stay within the part and the slots don't fully reach the edge of the part - fine, that's normal.
But if I set the end lines dotted BC doesn't just complete the slot, it whips outside, round the back and creates paths that will trash the part.
Pic attached shows
top - a profile cut for the open slot at the edge,
Middle - a pocket cut with solid lines at the ends of the selected geometry
Bottom - exactly the same as middle but with dotted lines at the end.
I tried draw geometry that adds tool radius at either end of the selected geometry and that results in failure to generate a roughing path,
It's far too squirrelly for me to pin down :-(
Nick

[magicniner]

I've been fiddling with all the settings and have found that it's having Adaptive Rough enabled that messes up the job, I can't imagine why it goes off and cuts outside the defined geometry with Adaptive Rough turned on, but it does ;-)

- Nick

[jrmach]

I've been fiddling with all the settings and have found that it's having Adaptive Rough enabled that messes up the job, I can't imagine why it goes off and cuts outside the defined geometry with Adaptive Rough turned on, but it does ;-)

- Nick

BobCAD Review V25 Open Pocket - YouTube

Open Pocket - YouTube

http://www.youtube.com/watch?v=zoJGO...7ea84b0MESMOs1

Post a .bbcd file

[magicniner]

File with working pocketing attached, if you turn on adaptive roughing in either Pocket the roughing paths go off on an unscheduled excursion,

- Nick
V25 Build 996

[jrmach]

JSYK,advanced rough/adaptive rough,,,is a ROUGHING tool path.


This file has lots of issues.If you not really making it,I'll pass.

[SBC Cycle]

Why would you use Adaptive Roughing when the size of the endmill is already 75% of the width of the slot? I can't explain the move outside the pocket but the choice of toolpath is not obvious to me. If the working file you posted looks ok to you, it should be obvious why Adaptive Roughing is not a good choice here.

[moldmker]

....if you turn on adaptive roughing in either Pocket the roughing paths go off on an unscheduled excursion....

It works....you just have to give the tool some elbow room.
Put your roughing tool down to 1mm and recompute.

[SBC Cycle]

It works....you just have to give the tool some elbow room.
Put your roughing tool down to 1mm and recompute.

That's probably a better way of putting it. I backed the tool down to 1MM and it worked for me as well. 4mm slot with 3mm tool and 0.2mm side allowance doesn't even begin to allow enough room for the Adaptive Rough to do it's job.

The toolpath is odd and I would report it to BobCAD development. Unless BCC staff can chime in and explain why it would wrap around the outside of the profile. Although the tooling or toolpath choice is poor for the job the move outside the pocket is concerning.

I believe the problem lies in the default value for the "smoothing" of the Adaptive Rough when using 2D-Pocket. There really should not be a crash here but I think some default values are coming in to play here and messing it up.

[magicniner]

It works....you just have to give the tool some elbow room.
Put your roughing tool down to 1mm and recompute.

That's a positive and helpful response, many thanks. There does seem to be a % of tool width for a slot out through an edge below which Adaptive will will nip out the back and get up to no good, I have a job in planning where narrow slots from the edges join with larger internal channels and I'll now know to test with adaptive and either turn it off or split the job if the same issue arises.

Why would you use Adaptive Roughing when the size of the endmill is already 75% of the width of the slot?

Excellent point!
And the answer is that as a beginner like many others I'm following tutorials and Training Professor Videos. The Open Pocketing tutorial I watched checked the adaptive box without mentioning in what situations it might be better left unchecked, now I know

JSYK,advanced rough/adaptive rough,,,is a ROUGHING tool path.

JSYKIK Yes, the two pockets have roughing passes leaving 0.1mm followed by a finishing pass. Nowhere in BobCad Cam Help does it mention that where Adaptive is used and the tool to work clearance on your job is a bit close you might get funny things happen, in fact there's no entry under Adaptive and the entry for Pocket is a sketch of one specific V-Carve instance rather than a useful reference on the parameters and options for Pocketing.

This file has lots of issues.If you not really making it,I'll pass.

I'm not really surprised, all I did was import the solid and Extract Edges to a new layer. Then Profile went fine then Pocket went funny, until I divined that Adaptive will do funny things if selected where not strictly needed there was no point in any further work. I'll probably work it through now, tidy it up and cut one as it's proving a good learning excercise, just a quick mention of any issues you spotted would have been much appreciated BTW.

Because there is no entry in Help for Adaptive Roughing, and only an example for V-Carve Pocketing in help under Pocketing, if this saves someone else an hour or more's buggering about trying to resolve an undocumented issue then that's great, and pretty much the point of posting ;-)

- Nick

[BurrMan]

I'm not sure of what the original intent for the pocket is, but the issue in the file is there is multiple "stacked" and various entity types. Here's a picture where I took one of the pockets and reselected the geometry for it and enabled adaptive and computed, without changing any parameters:

Attachment 206882

I think the geometry selection needs to be addressed. If you blank the solid, you can see the pocket areas have lines extracted. The end lines have dashed lines underneath. I would suspect that the pockets have 2 open ends selected? I selected the 4 edges and put them on a seperate layer, then set the linetypes as I wanted, on "just 4 entities". The pocket then works ok.....

[magicniner]

Yes,
The pockets have 2 open ends, I wanted to use Open Pocketing to cut the slots through the part, I selected geometry only from the layer with the lines with the solid blanked.
Without Adaptive selected it now generates nice paths, there's definitely space in the market for for a pocket "Dummies Guide to BobCad Cam", I'd buy one, I think I'd qualify! ;-)
ATB,
Nick

[SBC Cycle]

I'm not sure of what the original intent for the pocket is, but the issue in the file is there is multiple "stacked" and various entity types. Here's a picture where I took one of the pockets and reselected the geometry for it and enabled adaptive and computed, without changing any parameters:

Attachment 206882

I think the geometry selection needs to be addressed. If you blank the solid, you can see the pocket areas have lines extracted. The end lines have dashed lines underneath. I would suspect that the pockets have 2 open ends selected? I selected the 4 edges and put them on a seperate layer, then set the linetypes as I wanted, on "just 4 entities". The pocket then works ok.....

I played with that file for a while and always got the same toolpath. I just drew a 4mm x 60mm pocket in a brand new file (there are only 4 entities in it) and I still get the same thing. That is interesting.

[moldmker]

.... The pocket then works ok.....

Looks to me like your rougher isn't even engaging the part.