Which CAM Software?

[SBaircraft]

I'm thinking about getting a ShopBot and I'd appreciate some help in figuring out my CAM software needs. We design 3D parts in ProE and Creo. We normally work with IGES and STEP files. ShopBot comes with PartWorks 3D but it doesn't support these file typs.

ProE will allow me to save STL files that will work with PartWorks. However, it is my understanding that STL files are triangulated and that we will lose our smooth curves.

ProE will generate G-code but I don't have any experience with this function. Apparently ShopBot will accept some, but not all G-code commands. ShopBot told me that our G-code must be formatted correctly. I'm new to this and I have no idea what that entails.

Has anyone successfully cut 3-dimensional ProE or Catia designs on a ShopBot? What is the preferred method?

I like the ShopBot machines and community but the control system software doesn't appear to be a straight forward match with ProE. Am I better off looking at other routers that use more conventional G-code?

Thanks for the help! This is all very new to me.

[ssflyer]

Pro-E should have options to set the tessellation on STL exports, so depending on your requirements, the triangulation shouldn't really be an issue.

Since it will output G-Code, I assume you have one of the NC modules. Can you modify the post processors, or do you have to buy one from PTC?

My first step would be to ask them if their posts support ShopBots.

[zeykr]

Download the shopbot control software and run it in preview mode to test the g-code output from Pro-E. If you can modify the posts, chances are you can make it work.

[BrandanS]

Hi David,

We use SolidWorks for our design so we went with software called SolidCAM which is integrated. One of the cool things about it, is that they are currently working with me to develop a post processor for the ShopBot :D.

Brandan

[SBaircraft]

Thanks for the tips everyone. I looked into generating G-code with our ProE. Our software has more or less a demo of that capability but we'd need to purchase a very expensive plug-in to get full capability. From what I hear, it isn't very user friendly.

ShopBot said there are post processors available for Mastercam and Visual Mill. The Mastercam sales rep wasn't very familiar with ShopBot but insisted the job could be done with a bit of "massaging." The Visual Mill folks were more helpful. Their software will handle our IGES and STEP files and they have a post processor for ShopBot. The software comes in four configurations. The lower configuration is a reasonable $1,250. Unfortunately, it looks like we need the $5k version.

[SBaircraft]

I just tried saving a model as an STL file and I set the chord height and angle controls as small as ProE would let me. It doesn't look perfect but it isn't terrible either. That might be a good temporary solution until I can get a proper CAM program that works with both ProE and ShopBot.

[Burkhardt]

Keep in mind that the resolution/tessellation of the CAD output is only one part of the accuracy. Once yo have it on the machine you must decide on the overlap of your tool paths and I found that to be the limiting factor if you don't want to have the machine run for very long time. If the .stl resolution is much finer than your tool path steps it will not help you.

[Ger21]

What types of parts will you be cutting, and what materials will you be cutting?
I think it's safe to assume that a very large percentage of router users doing 3D cutting are cutting .stl's or other similar mesh format models.
The only times that I've seen faceting issues were with models with very coarse meshes. In the vast majority of cases, you'd never know the model was a mesh, and not made up of smooth curves.

[srwtlc]

You can import .stl into Aspire and then apply smoothing to the model after import. I imagine ArtCam will do the same.

[SBaircraft]

Burkhardt,

You made some great points. I also just read that ShopBot can't do smooth curves in the Z axis so maybe I can't do much better than a mesh model anyways? Faceted models will probably work for most of my work but a few of my parts need to be as precise as possible, such as laminar airfoil sections.

Gerry,

I mostly make composite aircraft parts. I will use the ShopBot to cut plugs from MDF, sometimes in several layers for taller parts. I'll smooth the plugs with surfacing primer and then pull fiberglass molds. I'm currently working on a belly pod to carry an airborne tsunami warning system.

Scott,

Thanks for the tip. I'll try downloading the Aspire demo and experiment with smoothing.

[Ger21]

From my experience, you won't need to do any smoothing in Aspire. I've never seen any faceted surfaces in my carvings.
I've also probably seen several thousand photos of 3D carvings, and have never seen any faceting unless there was a machine or code issue.

Even if you did have minute faceting, MDF is so soft that a light hand sanding with 220grit sandpaper would remove them with a quick swipe or two.

[bearcat]

David,

Where did you read that ShopBot can't do smooth curves in the Z axis?

Ed

[ssflyer]

David,

The ShopBot doesn't use the arc command for the Z axis, but that doesn't mean the results are not smooth. I've duplicated a lot of complex moldings with compound curves on my machine, and the results are pretty much an exact copy of the original.

[awerby]

It's just a matter of making them with enough polygons so that the angles between each one are not noticeable in the final part. If the CAM program you're using won't make one that's fine enough, you can scale it up 10x or so, and then reduce it in the CAM program.

I just got a Shopbot, and will be testing it out with VisualMill. Since it has a post for Shopbot, I don't anticipate any particular problems with smoothness in carving mesh-based models, and I don't see why the Z axis should be any different from the others in that respect. With the irregular contours that most of my sculptural carvings have, I never use the arc commands in any axis, and the curves come out smooth anyway.

Andrew Werby
www.computersculpture.com