[pjensen]

This has probably been answered, but my search-fu has failed me.

I'm evaluating BobCAD, and want to see if I can make a toolpath to cut out a shape, but leave some tabs so the shape wont fall out in the mill and jam the cutter. I called BobCAD and they said "nope, can't do that."

Really? How does anybody cut something out on a mill with BobCAD? Is there a work-around? I'm actually liking BobCAD fairly well, but this is kind of a show-stopper.

Thanks for any help with this! :rainfro:

-Peter

[Claude Boudreau]

You can always do them yourself using the break at screen each side of your tab then move the newly form entity in the +Z (the amount being the thickness of your tab)
Then just line join the higher line with the original contour.
You can make your tool follow this with 3d engrave.
This is ok for a single cut without stepdown.

there must be other way to make your tool follow your 3d contour with multiple stepdown
someone else with more experience than me with bobcad might help

Oh just tought of this, cut your profile as usual but leave maybe .25 inch.on the stock, then use the above procedure for the last pass.

[BurrMan]

You can use the contour command on entities and just have them start and stop at the tabs. Run a profile op will have it jump over all the tabs at the Rapid value height.

[Claude Boudreau]

You can use the contour command on entities and just have them start and stop at the tabs. Run a profile op will have it jump over all the tabs at the Rapid value height.

Good idea, how would you proceed to make your tabs not the full thickness of your stock ?

[BurrMan]

Good idea, how would you proceed to make your tabs not the full thickness of your stock ?

Could you do this from the parameters page of the profile feature? Just set it up to leave what you need for a tab. Or you could place geometry up in Z like you mentioned Claude.

[BurrMan]

Well that was wrong Claude. The parameters page wont do it. I did this using the stock edit and top of part settings. Set the stock down, then set the top of part along with the depth. You can see the rapids above zero, but the cuts stay down at the material.

[Magnum164]

This has probably been answered, but my search-fu has failed me.

I'm evaluating BobCAD, and want to see if I can make a toolpath to cut out a shape, but leave some tabs so the shape wont fall out in the mill and jam the cutter. I called BobCAD and they said "nope, can't do that."

Really? How does anybody cut something out on a mill with BobCAD? Is there a work-around? I'm actually liking BobCAD fairly well, but this is kind of a show-stopper.

Thanks for any help with this! :rainfro:

-Peter

Even though I have recently purchased BobCad, this is one of the reasons I am currently not using it. That and the Verify command is very lacking and can't see on my system. You would think as long as they have been in business, they would have a tutorial or something showing how to do this.

Make sure you try and do posts on your files. I could not post with the demo and the verify was not functioning. So now I am stuck with a lot of files it will not post with. So even though they gave me a competitive discount, I am reverting back for now to my original choice. I may give it another shot sometime in the future if they release continuous 4 axis.

[GeorgeRace]

Hi Peter:
If you have not, I suggest you give CamBam a try. It will do tabs with the click of just a couple boxes in the setup box.

I love the program, really does 2.5D very well, and is a winner in 3D as well.
George

[mcphill]

Make sure you try and do posts on your files. I could not post with the demo and the verify was not functioning. So now I am stuck with a lot of files it will not post with.

While it is annoying, they do clearly state that you cannot use models from the demo version in the full version. It is frustrating, but I can understand why they do it that way.

In addition they clearly state that you can't post from the demo mode. If you could post, it would not be a demo mode any more (it would be full functioning). If the verify is not working for you, call them and get it fixed. You first best bet is to reload you video drivers, and make sure you are on the most current version of BobCAD: http://www.bobcad.com/support/updates (again, not the video driver update reminder on this screen!).

The models you have, though, you CAN use (you can copy the layers from the demo program file, and paste it in to a new file made in the licensed version). Unfortunately I don't think you can copy the CAM paths from the demo to the full version. That said, you could save each CAM feature and load it in the full version, but you would need to reselect the geometry and boundaries if you used them.

[Magnum164]

While it is annoying, they do clearly state that you cannot use models from the demo version in the full version. It is frustrating, but I can understand why they do it that way.

In addition they clearly state that you can't post from the demo mode. If you could post, it would not be a demo mode any more (it would be full functioning). If the verify is not working for you, call them and get it fixed. You first best bet is to reload you video drivers, and make sure you are on the most current version of BobCAD: http://www.bobcad.com/support/updates (again, not the video driver update reminder on this screen!).

The models you have, though, you CAN use (you can copy the layers from the demo program file, and paste it in to a new file made in the licensed version). Unfortunately I don't think you can copy the CAM paths from the demo to the full version. That said, you could save each CAM feature and load it in the full version, but you would need to reselect the geometry and boundaries if you used them.

Well.. One thing to note, I am a programmer (game programmer) and I am using this on a $10K dollar computer I built myself which already has up do date video drivers for both cards. Advising people to keep current video drivers is very bad advice. I had to skip several versions before updating because there was an issue with the drivers that would have overheated my video cards. Updated video drivers means ones that are compatible with your system (just like your system BIOS), which I have. I have the latest version of BobCAD as well. The issue is in the software, not the system. Besides, the Verify is very lacking in features as well.

For the models, I am not using any that were created with the demo. These are all new models imported straight from Albire or Rhino (NX5 IGES). I really don't have time to sit on the phone with tech support, when I have can be making parts with another software package. But, I will send them examples and they can look at, as long as it does not generate 2500 more phone calls.

Actually, most of the top software companies will provide a fully functional demo version. At least for me, now I will not purchase software unless I can use a fully functional version. When BobCAD calls to update to the next version, it won't happen without a full demo to use. I don't mind limited capabilities, but you should be able to at least use each feature of the software. They can put a 30-60 day time limit on the software easily and allow full functionality.

[BurrMan]

Advising people to keep current video drivers is very bad advice. I had to skip several versions before updating because there was an issue with the drivers that would have overheated my video cards. Updated video drivers means ones that are compatible with your system (just like your system BIOS), which I have. I have the latest version of BobCAD as well. The issue is in the software, not the system. Besides, the Verify is very lacking in features as well.

Actually, most of the top software companies will provide a fully functional demo version. At least for me, now I will not purchase software unless I can use a fully functional version. When BobCAD calls to update to the next version, it won't happen without a full demo to use. I don't mind limited capabilities, but you should be able to at least use each feature of the software. They can put a 30-60 day time limit on the software easily and allow full functionality.

BobCads Demo softwares will post code for like the first week, then stop. (I dont remember the exact amount of time.) They are also supposed to be "fully functional and have no limitations" other than the fact that they dont post gcode. (I think the 3d toolpaths quit computing after that initial time slot too. FYI

As far as advice to update your drivers....This is "Common Practice" with developers when the issue is video related on a product that works. The built in predator verify is a very limited view of the feature cut and wont get any better with a driver update LOL. But it sounded as if you were having problems running the verify, and this would be a legitimate suggestion. The other thing to clear up with the verify is that if you are running the demo, it will only verify up to the posted code!!! So if you are being limited to "30 lines of gcode" with a demo version, the verify will halt 30 lines into the verify.... Again FYI

[Magnum164]

BobCads Demo softwares will post code for like the first week, then stop. (I dont remember the exact amount of time.) They are also supposed to be "fully functional and have no limitations" other than the fact that they dont post gcode. (I think the 3d toolpaths quit computing after that initial time slot too. FYI

As far as advice to update your drivers....This is "Common Practice" with developers when the issue is video related on a product that works. The built in predator verify is a very limited view of the feature cut and wont get any better with a driver update LOL. But it sounded as if you were having problems running the verify, and this would be a legitimate suggestion. The other thing to clear up with the verify is that if you are running the demo, it will only verify up to the posted code!!! So if you are being limited to "30 lines of gcode" with a demo version, the verify will halt 30 lines into the verify.... Again FYI

I am running the full version not a demo. Don't want to go OT but did want to clarify that.

[stevespo]

At some point last year I wrote a custom post (for Mach) that provides a simple form of tabbing. There were some issues with dealing with arcs, but it will break straight line movements, and create tabs of a desired length and height.

It's kind of a PITA to deal with installing the custom posts, but it's been documented fairly well on the BobCAD support site. If somebody wants to play with the code, I'm happy to pass it along. It's a bit limited, but I use it all the time and find it helpful.

I can package it up and upload it later tonight or tomorrow and perhaps someone else can give it a try and let me know what they think.

Steve

[BurrMan]

Tabbing has certainly come up before and I think I remember that Steves solution was liked and used by a bunch of the guy's involved in the last "how to tab" thread.

You may want to check this out....FYI.

Thanks for chiming in Steve. I couldnt find the thread where you last discussed this.

[stevespo]

Here are some things to play around with.

If you're using an unmodified Mach3-Router.MillPst then the easiest thing is to just drop these two files (look in the .zip archive for ArcFix-Mach3-Router.MillPst and ArcFix-Mach3-Router.CustomContour) into your C:\Program Files\BobCAD-CAM\BobCAD-CAM V23\Posts\Mill folder, and then select them as your active Milling Stock Post in the CAM Tree Manager.

When you are using a 2d Profiling toolpath, it provides a new Adv Posting dialog that allows you to turn on/off tabbing for that given profile. There aren't a lot of options, and they aren't very sophisticated. You can choose to put a single tab on a line that fits a given range for length (ie. > 1 and < 2 units), or you can choose to put multiple tabs on a longer line (say, tab every 2 units on a line > 12 units). (Note: If you enable both options, the single tab will take precedence over the multiple tab option, for a single line that satisfies both criteria. At least I believe that is the case.) Also, the tab width is hard coded as the tool diameter, but that could be a dialog option pretty easily.

Like I said, it's pretty basic and was written to satisfy a specific need that I had. Another limitation is that you have to key in your FINAL DOC in order to trigger the tabbing operation on the final cutting operation. If you get this value wrong, you will not get ANY tabs. So, if your final cut happens at Z level = 0.0, then you need to use this value. It should equal your "top of part" - "total depth".

If you already have a modified post, then the integration is kind of tricky. It amounts to hooking up specific post operations with my overridden behavior. I can explain this in detail, or it's covered over in the BobCAD support forum in the Post area. If you have programming experience, it's pretty trivial (but nasty and kludgy). The whole post interface is clumsy as heck and provides just enough functionality to be a tease, without giving you enough to do more sophisticated processing. That's one reason why I could never get tabs to work for arcs.

When you generate your tool paths you will NOT see changes on the screen. You will NOT see the tabs because it is happening on the post and is not visually represented by BobCAD. You will also NOT see the tabs if you use the BobCAD "verify" function because it does not operate on the NC code, but on the generated toolpaths without the post modifications. Argh. You should see them if you are using the Predator simulation module, but I don't own that, so I can't be completely sure. If it interprets the NC code, it should work fine.

You should see some comments in the NC posted code that the tabbing is happening, and you should verify them with NCPlot, which I find is always a good idea before actually running the code. You will also see them with Mach as a final sanity check. If you are doing many fine downward Z movements, the tab will ONLY appear on the final movement, regardless of what you have entered in the tab height dialog. This could be fixed, but wasn't necessary for my needs.

A side benefit of my custom post is that is also includes the "Crop Circle Arc Fix" in Program_Block_7. There should be no harm in running this, as all it does is turn tiny little arc instructions into straight line movements. You can comment it out if you'd like, but I'll leave it there because I find it very helpful with certain types of artwork.

Steve

[Claude Boudreau]

Was able to load these files , tried a few settings , not sure how this work, Dont see it in verify , dont have predator either, dont show up in gcode , dont appear in mach simulation...are you supposed to see z movements on DRO when doing a simulation in mach3? or do you have to actually cut to see...(If your top of material is at z=0 and stock thickness is .75 do you put -.75 for final DOC?)

Here are some things to play around with
If you're using an unmodified Mach3-Router.MillPst then the easiest thing is to just drop these two files (look in the .zip archive for ArcFix-Mach3-Router.MillPst and ArcFix-Mach3-Router.CustomContour) into your C:\Program Files\BobCAD-CAM\BobCAD-CAM V23\Posts\Mill folder, and then select them as your active Milling Stock Post in the CAM Tree Manager.

When you are using a 2d Profiling toolpath, it provides a new Adv Posting dialog that allows you to turn on/off tabbing for that given profile. There aren't a lot of options, and they aren't very sophisticated. You can choose to put a single tab on a line that fits a given range for length (ie. > 1 and < 2 units), or you can choose to put multiple tabs on a longer line (say, tab every 2 units on a line > 12 units). (Note: If you enable both options, the single tab will take precedence over the multiple tab option, for a single line that satisfies both criteria. At least I believe that is the case.) Also, the tab width is hard coded as the tool diameter, but that could be a dialog option pretty easily.

Like I said, it's pretty basic and was written to satisfy a specific need that I had. Another limitation is that you have to key in your FINAL DOC in order to trigger the tabbing operation on the final cutting operation. If you get this value wrong, you will not get ANY tabs. So, if your final cut happens at Z level = 0.0, then you need to use this value. It should equal your "top of part" - "total depth".

If you already have a modified post, then the integration is kind of tricky. It amounts to hooking up specific post operations with my overridden behavior. I can explain this in detail, or it's covered over in the BobCAD support forum in the Post area. If you have programming experience, it's pretty trivial (but nasty and kludgy). The whole post interface is clumsy as heck and provides just enough functionality to be a tease, without giving you enough to do more sophisticated processing. That's one reason why I could never get tabs to work for arcs.

When you generate your tool paths you will NOT see changes on the screen. You will NOT see the tabs because it is happening on the post and is not visually represented by BobCAD. You will also NOT see the tabs if you use the BobCAD "verify" function because it does not operate on the NC code, but on the generated toolpaths without the post modifications. Argh. You should see them if you are using the Predator simulation module, but I don't own that, so I can't be completely sure. If it interprets the NC code, it should work fine.

You should see some comments in the NC posted code that the tabbing is happening, and you should verify them with NCPlot, which I find is always a good idea before actually running the code. You will also see them with Mach as a final sanity check. If you are doing many fine downward Z movements, the tab will ONLY appear on the final movement, regardless of what you have entered in the tab height dialog. This could be fixed, but wasn't necessary for my needs.

A side benefit of my custom post is that is also includes the "Crop Circle Arc Fix" in Program_Block_7. There should be no harm in running this, as all it does is turn tiny little arc instructions into straight line movements. You can comment it out if you'd like, but I'll leave it there because I find it very helpful with certain types of artwork.

Steve

[stevespo]

Yes, that sounds like the easiest approach for your application. Just adjust your boundary and extents to include the tabs, and tool paths like slice planar should create them as part of the standard machining process.

Steve

[stevespo]

Claude, yes it is confusing. The scripting API is very primitive and that is the best I could come up with. My needs were also pretty basic, but it does work well.

Are you seeing the custom dialog under the Advanced Posting tab? What have you entered for values?
You are correct that if top of material is 0.0 and stock thickness is .75, then final DOC is -.75, provided you are cutting all the way through the part.

Remember, this will only insert tabs on straight line segments. You need to accurately enter what your final Z cutting height is, or you will not get any tabs. You can then configure how many tabs you want on each line segment, and have some level of control over which segments will get a tab (based on length).

The example (simple-tab-test.bbcd) will show how it works.

When you post the code, you will NOT see changes in the drawing on the screen. You will NOT see these tabs in the built in verify function. If you post the code, you SHOULD see some comments in the code that indicate where the tabs are happening. You WILL then see them displayed in a program like NCPlot, or just by loading the NC file into Mach and rotating the object so you can see the Z tool paths.

Steve

N01 G01 Z.25 F60.
N02 Y-.75 F120.
N03 G17 G03 X-.75 Y-1.0625 I.3125 J0.
N04 G01 X.75
N05 G03 X1.0625 Y-.75 I0. J.3125
N06 G01 Y.75
N07 G03 X.75 Y1.0625 I-.3125 J0.
N08 G01 X-.75
N09 G03 X-1.0625 Y.75 I0. J-.3125
(*** Downward ZFeed: Contour Final Pass ***)
N10 G01 Z0. F60.
(*** Start Tab ***)
N11 Y.125 F120.
N12 Z.1
N13 Y-.125
N14 Z0.
(*** End Tab ***)
N15 Y-.75
N16 G03 X-.75 Y-1.0625 I.3125 J0.
(*** Start Tab ***)
N17 G01 X-.125
N18 Z.1
N19 X.125
N20 Z0.
(*** End Tab ***)

[Claude Boudreau]

On your sample tab file, the straight entities are 1.5 unit long so you should get tabs ok. I dont see any indication of tabs in the post...

Claude, yes it is confusing. The scripting API is very primitive and that is the best I could come up with. My needs were also pretty basic, but it does work well.

Are you seeing the custom dialog under the Advanced Posting tab? What have you entered for values?
You are correct that if top of material is 0.0 and stock thickness is .75, then final DOC is -.75, provided you are cutting all the way through the part.

Remember, this will only insert tabs on straight line segments. You need to accurately enter what your final Z cutting height is, or you will not get any tabs. You can then configure how many tabs you want on each line segment, and have some level of control over which segments will get a tab (based on length).

The example (simple-tab-test.bbcd) will show how it works.

When you post the code, you will NOT see changes in the drawing on the screen. You will NOT see these tabs in the built in verify function. If you post the code, you SHOULD see some comments in the code that indicate where the tabs are happening. You WILL then see them displayed in a program like NCPlot, or just by loading the NC file into Mach and rotating the object so you can see the Z tool paths.

Steve

N01 G01 Z.25 F60.
N02 Y-.75 F120.
N03 G17 G03 X-.75 Y-1.0625 I.3125 J0.
N04 G01 X.75
N05 G03 X1.0625 Y-.75 I0. J.3125
N06 G01 Y.75
N07 G03 X.75 Y1.0625 I-.3125 J0.
N08 G01 X-.75
N09 G03 X-1.0625 Y.75 I0. J-.3125
(*** Downward ZFeed: Contour Final Pass ***)
N10 G01 Z0. F60.
(*** Start Tab ***)
N11 Y.125 F120.
N12 Z.1
N13 Y-.125
N14 Z0.
(*** End Tab ***)
N15 Y-.75
N16 G03 X-.75 Y-1.0625 I.3125 J0.
(*** Start Tab ***)
N17 G01 X-.125
N18 Z.1
N19 X.125
N20 Z0.
(*** End Tab ***)

[stevespo]

Claude, can you describe to me what you are doing?

When you load the sample file (simple-tab-test.bbcd), make sure you have the ArcFix-Mach3-Router.MillPst selected as the post processor.
By default, the example should put one tab on each line segment. Then just Post the code, and you'll see the comments embedded that describe what is happening with the tabs.

You won't physically see the tabs because they're not part of the actual on-screen model.
Can you describe what is happening, and post the code that is being generated?

Steve