CAM Questions.

[ennova]

Hello,

I'm currently a student at my local university and I'm trying to get a my hobbyist CNC setup going in my garage. Around January I bought a machine made by blurrycustoms.com and it seems to be a well built machine for my first machine. It has taken me a long time to get everything set-up as I'm short on time and money (working part/full-time and attending classes). I still have a few things that I needed to do with my machine before I am satisfied and gear towards making stuff with it. I.E. I need linear rail/ballscrew covers, set-up a dust collection system and build a case to encase the machine to minimize the amount of dust that gets everywhere. So I'm not in a big hurry to as far as software goes, however I'm starting to really look into what I'll be needing so I know what to buy/use when I am. I am hoping to be able to use my machine to make a variety of different things such as: an electric guitar body, xbox 360 laptop case, lithographs, small signs, perhaps even some simple circuit boards, etc...

Currently I have access to a computer lab that has Solidworks 2010 and I'm becoming familiar with the use of this CAD program. Even though my skills are very amateurish at best I feel very comfortable with Solidworks. I will be taking an engineering class next semester that will definitely be using CAD software of some sort hopefully Solidworks, however I do not know if it will go over any of the CAM software. I have downloaded a few trial versions of a few CAM programs and I am finding that I really have NO IDEA what I am doing with any of the CAM software. So finally here are my questions:

1. What makes those expensive CAM programs so expensive? What advantages to they have over their cheaper counterparts?

2. What is 2.5D? I understand the difference between 2D and 3D, but what constitutes 2.5D as far as CAM programs go? Why not simply be 3D?

3. Are their any programs out there that can work natively with Solidworks part files?(not integrated into Solidworks because I can't modify the computers in the computer lab) Or is working with dxf files the "way to go"?

4. When I import a DXF file ( or any file) into a CAM program what is the common procedure to produce the G-Code I need for Mach 3? I mean what is the Flow chart? Import -> create toolpaths -> output G-code?

5. I have been looking at different CAM options, in particular CamBam and vectric's cut2D + cut3D + photoVcarve. Would these options suite me well assuming that most of the CAD work I would do would be in Solidworks (except the lithographs with photoVcarve)? Are they any others that I should consider assuming that I don't want to go over $1000?

6. Are there any limits to what these CAM programs(especially the ones I am considering) can do as far as generating G-code? I mean could they make G-Code for any model that I could create in Solidworks assuming that my 3-axis machine could physically cut it out? (I mean not a "physical" impossibility more a "that object is too complicated to create the said G-code for.)

7. What is the best way to learn these CAM programs? I really have no idea what I'm doing or how to create the G-code.

Thanks for your time reading my post and any advice you can offer me, even if you aren't answering any of my questions. I would really appreciate anything you can offer me.

[mcphill]

1. What makes those expensive CAM programs so expensive? What advantages to they have over their cheaper counterparts?

Ease of use and advanced support for complicated tool geometries, etc. are what make the higher end systems more expensive, but the gap between hobby level and elite pro level is closing fast!

2. What is 2.5D? I understand the difference between 2D and 3D, but what constitutes 2.5D as far as CAM programs go? Why not simply be 3D?

2.5D is 2D on different level planes. The Z axis never moves at the same time as X and Y. 3D is simultaneous motion of X Y and Z. You should only consider programs that can do full 3D.

3. Are their any programs out there that can work natively with Solidworks part files?(not integrated into Solidworks because I can't modify the computers in the computer lab) Or is working with dxf files the "way to go"?

Yes. I suggest you look in to BobCAD v23. DXF is no good if you want to work in full 3D files.

4. When I import a DXF file ( or any file) into a CAM program what is the common procedure to produce the G-Code I need for Mach 3? I mean what is the Flow chart? Import -> create toolpaths -> output G-code?

Import, created tooling paths, generate G-Code, post-porcess for your machine. The post processor converts "generic" code in to code the will work with the specific controller on your CNC machine.

5. I have been looking at different CAM options, in particular CamBam and vectric's cut2D + cut3D + photoVcarve. Would these options suite me well assuming that most of the CAD work I would do would be in Solidworks (except the lithographs with photoVcarve)? Are they any others that I should consider assuming that I don't want to go over $1000?

Look in to BobCAD V23. You should be able to get set up for about $600. It will take a while to get them to come down to this price, but hang in there and you can get it. Make sure you get Mill Pro, BobART, and Predator Editor at a minimum, at that $600 price. It is too bad you don't have your own SolidWorks seat, as BobCAM is a plugin to SolidWorks and works great - very slick integration, and as you change the SW model, the CAM automatically adapts... If you ever get SW, BobCAM can be had for around $750. Unfortunately you can't apply a V23 purchase to a BobCAM purchase...

6. Are there any limits to what these CAM programs(especially the ones I am considering) can do as far as generating G-code? I mean could they make G-Code for any model that I could create in Solidworks assuming that my 3-axis machine could physically cut it out? (I mean not a "physical" impossibility more a "that object is too complicated to create the said G-code for.)

The main limitation is the types of tools supported. BobCAD only supports simple endmills, ball mills, and bullnose. No funky undercut mills, V shaped mills (other than for V-Carve tooling paths). The geometry itself is not a problem, it can be as convoluted and complex as your mind can create. The more complicated it is, the smaller the tool you will need to use if you make sharp turns.

7. What is the best way to learn these CAM programs? I really have no idea what I'm doing or how to create the G-code.

For BobCAD, there are tutorial CDs, and there are some videos on BobCAD and YouTube. You can also take the training class from BobCAD, which I took and felt was worth every penny. Best case would be to work with someone locally that already knows the software...

[ger21]

1) They can work with native SW files, and detect features like curves and holes. For 3D work, they can be much more efficient.

2) For all practical purposes, 2.5D is 2D work. The extra 0.5D is the Z axis, which allows you to ramp in to cuts, plunge, and do helical moves to cut holes. But it's basically for work where all the features are flat bottomed or flat on top. You can have many different Z levels. Think of it as the Z moving into position, then the X and Y doing most of the work.

3) (and4) Yes, the expensive ones. Depending on the CAD and CAM you're using, the workflow may be different.

Normal workflow with Cut2D is toeither draw the part in Cut2D, or import a 2D .dxf file. If you have a 3D Solidworks model, you'll need to create a 2D drawing of the part and export that. A 2D CAD program can be a lot faster sometimes. Once you have the dxf (vectors) in Cut 2D, you select them and assign operations (toolpaths) to them. Once the toolpaths are created, you export the g-code.

With Cut3D, you export an .stl from your SW model. Import into Cut3D, create toolpaths, export g-code.

The more expensive ones can be far more complex, but also offer far more control for 3D work.

5) You might want to consider V Carve Pro instead of Cut2D. For doing guitars, for example, you can create body contour toolpaths in Cut3D, and import those toolpaths into V-Carve Pro, where you can create pocket and profile toolpaths that will cut much faster. These can be combined together and exported in a single g-code file.

It's possible to do an entire guitar in Cut3D, but it's not the most efficient way. But it would be the cheapest. But also keep in mind that a Tele is a lot different than a PRS, and would possibly be done quite differently.

V-Carve Pro can do a LOT more than Cut2D, though. The extra features may or may not be worth the extra money to you.

6) The user's ability would probably be the main limit. The learning curve can be steep, but where there's a will, there's usually a way. And someone on Vectric's excellent forums can most likely show you the way, if needed.

7) Download the demo's and start practicing. There's plenty of tutorials, and again, their forum members are always glad to help. http://www.vectric.com/WebSite/Vectr..._tutorials.htm

[blowlamp]

I suggest you download CamBam (v9.8.0 is the latest pre-release beta ). It does 2D/3D and would be able to do any of the jobs on your list. It doesn't have the fancy graphics display that some of the other products have, but it is immensely capable in its abilities. Check that other software is able to do leadin/leadout moves (ramping) and has a tab facility (bridges) to prevent the finished part from dropping from the stock and being damaged by the cutter. The demo version is totally unrestricted for the first 40 trials, and then reverts to producing a limit of 500 lines of code. The price is unbeatable in my opinion.
Lastly, the CamBam forum is excellent and the people on there will help you with any questions you have about making your parts.

Martin.

[awerby]

Enova wrote:


1. What makes those expensive CAM programs so expensive? What advantages to they have over their cheaper counterparts?

[There's a lot that goes into pricing decisions for software. Basically, the company has to decide if it's making a program that only a few people will use, or one that is trying for a larger market. More users will allow the company to be supported with fewer sales; fewer users mean each one has to pay more.]


2. What is 2.5D? I understand the difference between 2D and 3D, but what constitutes 2.5D as far as CAM programs go? Why not simply be 3D?

[2.5D programs typically use linear inputs, usually a closed region of some sort, and assign a depth or height to it. A 2.5D pocketing program will remove material from the region, while a facing program will remove material around it. For 3d to work, you need a 3d model of some sort that the program can follow to make a part; with 2.5d that's not necessary.]

3. Are their any programs out there that can work natively with Solidworks part files?(not integrated into Solidworks because I can't modify the computers in the computer lab) Or is working with dxf files the "way to go"?

[Yes, there are programs that work with native Solidworks files. For instance, Mecsoft makes VisualMill for Solidworks: http://www.mecsoft.com/vmforsolidworks.shtml . But it does plug into the Solidworks workspace, so it might not work for you. DXF files come in various different flavors; some are 2d only, and some support meshes (3d faces). But it's more common these days to use STL for mesh models, since it is supported by additive 3d printers as well as many CAM programs.]

4. When I import a DXF file ( or any file) into a CAM program what is the common procedure to produce the G-Code I need for Mach 3? I mean what is the Flow chart? Import -> create toolpaths -> output G-code?

[That's basically right, but you need to step through some specifications before generating toolpaths. For instance, the program needs to know what size and type of tool you want to use, what kind of machine it's making code for, the area it's supposed to be addressing, the feedrates and spindle speeds you want to use, how finely it's cutting the material, how much stock to leave for a finishing pass, etc.]

5. I have been looking at different CAM options, in particular CamBam and vectric's cut2D + cut3D + photoVcarve. Would these options suite me well assuming that most of the CAD work I would do would be in Solidworks (except the lithographs with photoVcarve)? Are they any others that I should consider assuming that I don't want to go over $1000?

[You might look at VisualMill, which has good 2.5D functionality as well as 3d capabilities. I sell it for $800, although there's a Pro version with fancier features that goes for more. If you're a hobbyist, we're offering a $1000 - off special on DeskProto 5.0 right now, which is a killer deal, since the program normally sells for $1300. It's basically a 3d-only program, but it has a lot of useful features like a 2-side wizard, which allows you to flip your part over to cut the reverse side without losing registration, 2d to 3d relief generation, freeform machining regions, 2d engraving on 3d parts, etc. You can try it out by downloading it from www.deskproto.com ; the demo will be fully functional for a month.]

6. Are there any limits to what these CAM programs(especially the ones I am considering) can do as far as generating G-code? I mean could they make G-Code for any model that I could create in Solidworks assuming that my 3-axis machine could physically cut it out? (I mean not a "physical" impossibility more a "that object is too complicated to create the said G-code for.)

[Deskproto is good at dealing with very complex models without choking. But in order to carve any 3d form, you have to be able to hold the stock down and reach the whole surface with a tool, so undercuts, etc. can be a problem. Then you have to consider what's the best way to cut something, so toolmarks are minimized.]

7. What is the best way to learn these CAM programs? I really have no idea what I'm doing or how to create the G-code.

[There's a lot of variation in learning curve between various CAM programs, and they provide various levels of support. Some have online tutorials, some provide training classes or on-demand training, some require a semester of college-level classes to master. Deskproto is one of the easiest to learn; you can pretty much figure it out from the demo, and the wizards make things even easier by setting things up for you and stepping you through the process. VisualMill isn't too much harder to learn, and there's a range of training and support options available.]

Andrew Werby
www.computersculpture.com

[ennova]

Thanks for all the great replies, I really appreciate it. I'm looking into all these programs mentioned. I got a call from the BobCad-Cam guys and they offered me an amazing deal, however I truly don't have any extra money to spend at this time(books for school are getting too expensive). They told me they'd extend the offer until Friday, I'm not sure if I'm going try and jump on it or not.

I'm still considering everything mentioned here though, it is a lot to take in and I can't really afford to "buy twice". Thanks so much for your insights.

[mcphill]

Thanks for all the great replies, I really appreciate it. I'm looking into all these programs mentioned. I got a call from the BobCad-Cam guys and they offered me an amazing deal, however I truly don't have any extra money to spend at this time(books for school are getting too expensive). They told me they'd extend the offer until Friday, I'm not sure if I'm going try and jump on it or not.

I'm still considering everything mentioned here though, it is a lot to take in and I can't really afford to "buy twice". Thanks so much for your insights.

The high-pressure-sales is the biggest downside of BobCAD (the software is really good, the sales tactics are annoying/suck/piss people off). It is NO rush, you can get that deal any time (and probably better). If you don't have the cash now, just ignore them until you do - there truly is NO rush...

[andy55]

I'm still considering everything mentioned here though, it is a lot to take in and I can't really afford to "buy twice". Thanks so much for your insights.

Take a look at HeeksCAD:
http://code.google.com/p/heekscad/
it is free and open-source, but it's not very complete or bug-free...
if you are a programmer you can modify/add to it.
It has 2D machining through libarea and libactp:
http://code.google.com/p/libarea/
http://code.google.com/p/libactp/
I've been working on some 3D machining routines here:
http://code.google.com/p/opencamlib/