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Cleaning up simple pockets in CAD/CAM ?

RobotTranslator

Aluminum
Joined
May 18, 2015
Location
Rockford,IL
:)
I wanted to ask some of you a simple question about Pockets and cleaning them in your CAD files.

What i'm doing is milling a radius pocket part way down but in my CAD it leaves a bit of left over stock where the cutter simulation doesn't clean up.
This might not even exist in the real world when the program runs but I like to do everything i can to make a simulation look like the reality before I run a program.

Now I already figured ill just run a simple sweep of the same geometry with a regular old profiling operation to get the residual stuff out of the way before I run my pocket op.
(the pocket isnt closed so its easy to mill out)

I honestly just wanna ask what other Cad/Cam users do in a situation when the pathing leaves a little left over?
Just hoping to learn any tips or tricks :scratchchin:

Thanks in advance everyone!!

(I use BobCad V27 nothing fancy it gets the job done though)
 
A picture would be great to make sure we're talking about the same thing!

If your pocket has matching wall and floor radii, then that will leave a triangle shaped leftover on the floor no matter what size tool you used to finish the majority of the floor. If that's what you're talking about, then I draw geometry the same as that leftover triangle and run the ball nose you used in a 3D toolpath contained by the geometry I drew, and held off the walls .001" or so to finish those areas.
 
Screen shot here

Hi thanks, yea i forgot to update this workstation had to get something to get a screencap for the post ! sorry bout that.

Here is the issue, its the little radius left over at the edges of the part as Im doing the pocket, like i said its nothing bad im just looking to learn how others deal with things like that.

Though im sure im gonna have issues with bottom clean up too some day.

:ack2:

EDIT: I should note that the defined boundary of the pocket is likely the cause of the issue, im not stumped just want to know how more experienced people do things
 

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Hi thanks, yea i forgot to update this workstation had to get something to get a screencap for the post ! sorry bout that.

Here is the issue, its the little radius left over at the edges of the part as Im doing the pocket, like i said its nothing bad im just looking to learn how others deal with things like that.

Though im sure im gonna have issues with bottom clean up too some day.

:ack2:

EDIT: I should note that the defined boundary of the pocket is likely the cause of the issue, im not stumped just want to know how more experienced people do things

I don't use Bobcad and your picture is very small but it appears like you are are trying to get the main pocket shape to run out of the side of your part. If that's the case it appears like you are selecting a closed boundary so it's leaving the excess at the side opening. I'm assuming you are using boundary driven paths, in which case you'd need to offset the boundary on the open side of the pocket. You could use an open boundary for a finish path on the walls and you'll need to extend either the boundary or the path (if Bobcad supports that) to get you tool to start and finish off of the part. Again, I don't have Bobcad experience so I speaking of a strategy, not specific selections to do in Bobcad.


NX 12.0.1
NX 12.0.2
 
It might be how you are defining the stock. It might be how you are defining the lead in and lead out.... Not enough info there. Al dePaolo is the BobCad guru. He has a lot of videos up, "Bobcad after dark" - on youtube.
 
Yea I am using a closed pocket for this example.
I thought it might be as simple as extending boundary lines or stock.
Nothing to bug Al about honestly I just am happy to have the thoughts of you guys who know more than I do so i can learn faster from your experience.

Im just learning how to use the different styles of pocketing available with my software. I apologize that the image is small. Im sort of flying by the seat of my pants here on things in this shop.

I swear BobCad can allow me to do an open pocket boundary but I just cant get that to work yet, but I will get it im sure.
Thanks again guys, honestly just like to see what kinds of answers I get from these little questions like this.
 
In Mastercam I would either draw my own geometry and extend as needed, or use "Adjust Start (end) of Contour" and extend the path by about 55% of the tools diameter.

However, if that is your finish pass, I would have a .005" to .015" radius at the start / end of that edge as to wrap the corner, so no manipulation of geometry needed in that case.
 
Yea I am using a closed pocket for this example.
I thought it might be as simple as extending boundary lines or stock.
Nothing to bug Al about honestly I just am happy to have the thoughts of you guys who know more than I do so i can learn faster from your experience.

Im just learning how to use the different styles of pocketing available with my software. I apologize that the image is small. Im sort of flying by the seat of my pants here on things in this shop.

I swear BobCad can allow me to do an open pocket boundary but I just cant get that to work yet, but I will get it im sure.
Thanks again guys, honestly just like to see what kinds of answers I get from these little questions like this.
Use a broken line of some kind for the open side of the pocket. Doesn't matter what kind, just not a solid line.
If your tool is too big to clean up the corners, use a smaller tool, or "rest roughing."
You don't have to bug Al to search the videos. Hundreds, maybe thousands of youtube BobCad videos.....
 
RobotTranslator,

I'm not a BobCAD user, but in Fusion 360, I would just create a 2d "path" (in a separate sketch) that is offset 1/2 your cutter diameter inward of the edge of your pocket.

Rough out the pocket (finish the floor, but leave a touch of stock on the wall), and then drive a final cleanup pass off that sketch line (on center).

I won't say I have to do it often, but occasionally I just can't get some weird pocket shape to finish correctly on the wall, and doing a final pass off a separate line path seems to just about always solve the problem.

fwiw...
PM
 
APT? Zzzzzzzzzzzzzzzzzzz
Super old school software, text based. Automatically Programmed Tool.
Think 1980's, will run on the old 286, even without a math co-processor. Runs better with one, or even on a 386. I might even have the notes for the classes way back then.
Very powerful and flexible and cheap for it's time. Kinda like dBase3 or 4 though, you have to know what to type at the blinking cursor.
Just mho, ymmv............
:)
 
I remember upgrading to Mastercam from APT....rewind the clock there..

Not too familiar with Bobcad, but in mastercam, I'd do an open chain, and just extend the contour using lead in/ lead out. Perhaps Bobcad has something similar.
 
Hey guys , just a follow up to my thread. Thanking everyone for lovely suggestions and tips that are always going in my tool bag when ever I can learn something new from you all.
Anyway I got sick and was out of the shop for a few days, the parts that had been the source of my question got finished in that time thankfully.
But the overall knowledge gained is a reward in itself.
I'll keep improving and I know I will have something new to ask about soon.

Thanks again guys !
- RT
 
I use bobcad as well, and in the same situation I went around the edges of the pocket utilizing the side roughing cycle.. in my case a 3/16" BNEM with .015 step-over was good enough, but you can program in any number and size of steps.
I pay for Bobcad support, but they couldn't figure this out... they showed me a half dozen strategies that would not go.
This was mine.
 
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SOLVED! Open Pockets and Dotted Lines

Well would you know it, the type of thing I was looking for was as simple as putting a dotted line in my geometry to indicate that the border of a pocket was open.
Thanks @eaglemike for the tip on that!
Something simple that I didnt know just because of my lack of experience.
Learning this nifty fact has opened up a huge amount of options for me!
Thanks everyone once again.

Found this vid by Al that cleared things up for me !!

Open Pocket - BobCAD CAM V3 - YouTube
 








 
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