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View Full Version : Trouble creating toolpaths for Crown



robinsoncr
07-25-2007, 02:47 PM
Hi Turmite &/or Joakim,

I'm trying to machine this crown with dentil that I created. I can create a roughing operation but not acceptable finishing operations. I have .125" endmil, .125 ballmill, .25 endmill, .25 ballmill, .375 endmill, .375 ballmill. I attached the drawing in a shortlength to save size. It should be 120" long.

When I try to create a finishing toolpath, any of them, any tool, it freezes. I've let the pc run 2 hours with no result. Just hangs up. I'm running it on a P4, 2.4ghz dualcore, 2gb ram, nVidia 7600GS with 512mb vid ram. I have loaded and machined more complex parts in the past.

I have also tried removing the pockets between the squares that make up the dentil, just machining the overall profile. Same issue.

Let me know what you think.

Thanks,
Chris

under-dog
07-25-2007, 04:11 PM
What CAM converter asre you using.

I use Solid Works.

I am not sure if this is an issue because I have only dabbled with Rhino:

I opened the file in a demo I have. I noticed that you had multiple bodies(parts or whatever Rhino adresses them as). in that single part file. I was able to move parts all over the place. Nothing was mated with anything else or merged together.
Could this be creating the issue?


Depending on how Rhino creates STL files and or tool path files it could be finding an issue with the fact that they are not merged together. It may be having issues figuring out how to machine the faces that are internal and adjacent to other parts. Or if there are gaps between them.

I would try merging them together and take another whack at it.

In SW when you genertae an STL file it will merge seperate and touching bodies into a single cohesive STL geometry. However the proper manner is to merge all the bodies in a part into on body.

under-dog
07-25-2007, 04:14 PM
not to mention there was what looked to be a surface body in there(left hand face of the part---side profile). This may cause issued as well. I know that in Solid Works only solid bodies are eligable for STL.

under-dog
07-25-2007, 04:15 PM
surfaces under each of the squares as well

robinsoncr
07-25-2007, 06:07 PM
Under-dog,

Before I cut the model down, I had ungrouped the parts. I'll try eliminating the surfaces and then group the final parts into a model.

I'm using Rhino V4 + Madcam4.

Thanks,
Chris

turmite
07-25-2007, 08:00 PM
Hi Chris,

Joakim doesn't have access to high speed internet or maybe even at all right now so I'm it. I have a summer cold and my head feels like it has a basketball on the inside.

I will take a look and see what I can find.

Mike

turmite
07-25-2007, 08:34 PM
Chris I just ran a finish tool path with a .250 flat cutter and did a remachine with .1 flat cutter both using planer surfacing. It spit the code out in just a couple of seconds.
I'll send you a pm with my ph 3 and you can call if you would like.

Mike

robinsoncr
07-26-2007, 09:33 AM
Turmite,

When I select a 120" section of molding to load into madcam, I get "ERROR! POLYGON ALLOCATION", apparently for each polygon!

I can machine a 2" sample. Not a full length of molding. Interesting, I can load into RhinoCam Pro demo and machine it without error.

Chris

robinsoncr
07-26-2007, 12:10 PM
I removed the dentil all together so that I could either machine it seperately or purchase it and apply it to the molding.

I then, created the roughing toolpath without issue. Tried to create a planar toolpath with a .25 ballmill. Running 3 hours later and the pc is showing cpu useage as 50% and nothing is happening...that I can tell.

Chris

dcd121
07-26-2007, 01:40 PM
I loaded your file as is and madcam would not recognize it. I then imported it into a blank .3dm file set up for inches. madcam recognized it and toolpathing did not freeze and worked as expected.
Dave

turmite
07-26-2007, 06:37 PM
Chris I agree with Dave on this one. I think the problem is more the model than Madcam. Now why it won't recognize it I don't know, though it did on my system, and I don't have that great a system.

I am curious if this is an real time project you are working on, or is it for practice. If for real, there are much faster ways to produce modling than on the cnc. I know you know that, but I am curious what your thinking is?

Mike

robinsoncr
07-27-2007, 01:07 PM
Turmite,

This is a realtime project for furniture. You can create straight pieces of molding easier using a molder but if you need anything other than straight, your limited.

Right now, I'm trying to learn how to create a better model of the crown.

The furniture pieces that we are started to produce have alot of carvings and modeled molding, so this is going to become more critical for us over the next several months.

Chris

dcd121
07-27-2007, 03:17 PM
Chris,
I fooled around with toolpathing your crown model and there is really nothing wrong with it. It is just a matter of milling those dental squares. The small size bit needed to get any detail is not practical (in my opinion) from a time standpoint. The molding minus the dental pieces is practical. I have made a few circular mirror frames which have a simpler profile but the same concept. I find that using the largest ballnose bit that is practical with a small stepover works best. I use a .5 flat end for roughing . The dental strip could be made separate with 2d profiling and applied. If that does not work I would use regions to isolate that area and use a small cutter in that area.

As far as carvings , if you can get your file into Rhino you can carve it. (sorry, I know you know that).

I am glad there is some action on this forum. The more Rhino/Madcam users the better.

Regards,
Dave
(furniture maker specializing in veneer)

robinsoncr
07-27-2007, 04:15 PM
Dave,

Thanks for the feedback. You're right about the dentil detail. Originally, I was going to cut the dentil detail between blocks with a pocket routine or something similar but cut the overall profile beforehand.

I couldn't understand why I was having trouble with the error message. I've loaded and machined much larger files with many, many more complex surfaces without trouble.

I went in and tried simplifying the model and this did seem to help a little.

Are you using any software to create 3d carvings to use on furniture?

Chris

dcd121
07-27-2007, 05:18 PM
Are you using any software to create 3d carvings to use on furniture?

Busted! No the nature of my work does not require carving . 98 % is 2d parts cut for veneer underlayment. cnc beats the heck out of running a hand router. My little nitch is curved forms surfaced with veneer that become tables,casegoods etc. Second is veneer inlay.

Have you tryed an models from this site?
http://www.carve3d.com/

Pickup an STL model and test it ( I think they have a few free ones)
Keep us posted.

Regards,
Dave

turmite
07-27-2007, 09:38 PM
Dave,
I went in and tried simplifying the model and this did seem to help a little.
Chris

Hi Chris,

I ask my questions to find out what you just told me. This is a learning experience and I think you are right for testing much both with Rhino and Madcam.

I was going to suggest that you rebuild your geometry in rhino as I found several things that would have made it easier to cut. I have been the past week and was basically in bed all day. I'm bored. Do you mind if I rebuild the profiles and the dentil section showing how I would make it? Sometimes different eyes see things from a much different view.

Mike

turmite
07-27-2007, 10:06 PM
Hi Chris,

Attached is the rebuilt 3dm. I took all the extra surfaces, re-extruded and capped on the large section. I did the same on the dentil piece but I also booleen unioned the individual squares to the trim section making a single polysurface. I then copied it and move the dentil section down some. The two seperate sections is how I would machine it.

How much of this trim are you going to need? If very much, some custom ground cutters would sure benefit you.


"I couldn't understand why I was having trouble with the error message. I've loaded and machined much larger files with many, many more complex surfaces without trouble."

In regard to this statement, I personally think it may have been the extra surfaces, especially if you used a window for selection and selected everything Try the model I attached and see if it works for you.


Hey if I can be of further service let me know.

Mike