The Cerebral Forum

CNC Projects => CNC Questions and Answers => Topic started by: wing_nut on January 20, 2009, 03:44:11 PM

Title: CAM software
Post by: wing_nut on January 20, 2009, 03:44:11 PM
Hello to all

I design model hulls in a CAD software and I generate DXF files (see my introducing post)

I am looking for free CAM software. I am testing CamBam and gCad3d, but I need help documentations and tutorials to start.
Is someone have link (other than cerebralmeltdown, gCad3d and CamBam sites) to examples, helps or tutorials ?

Is someone use other free CAM software ? Can I have user's feedback on this kind of software ?

I apologize for my poor english language.

Ecrou Papillon
Title: Re: CAM software
Post by: Gabriel on January 22, 2009, 08:38:25 PM
I'm sorry to say that there is a good chance that the documentation you've been looking for probably isn't available.  Although, I can't be absolutely certain about the gCad3d program because I have never used it before.  The only place I've seen CamBam tutorials is on the CamBam website and the CamBam forums and I'm sure you've probably looked there.

Here is a link to a free program for CAM called FreeMill. It is somewhat limited because you can't set the depth increments on it, but since you said that you're only cutting blocks of foam it might not really matter.
This company actually called me on the phone about a month after I registered to try and get me to buy the full version, so keep that in mind if that sort of thing bothers you. They only called once though, so it wasn't too much of an inconvenience.

Here is a link to another program called MeshCam. It's not free, but it is fairly cheap and easy to use. There is a 30 day demo which might be enough time for you to get what you need out of it.

If you have a DXF file of a sailboat hull already made and don't mind sharing, I could take a look at it and hopefully be able to give you better advice once I have a better idea what you're trying to do. It's possible that you won't be able to do what you want using free software, but I'm willing to keep looking for a free solution if you are. :)
Title: Re: CAM software
Post by: wing_nut on January 23, 2009, 03:35:51 PM
Hello Gabriel and all future visitors

Thanks for your answer.

Notice that, du to my activity, I can't read the forum every day. I try to look at it at least the weekend.

I am going to try to explain you my design process of model sailboat hull. If you think it is out of scope this forum, feel free to inform me.

First point, I have to congratulate Lester Gilbert for his usefull site I use the spreadsheet.
I get the mathematical definition of the hull. I wrote a C program to generate all the points in a file. I load these points as line in a CAD program and export a DXF file.
To build the hull from foam, and to avoid deformation when gluing carbon fiber, I work on a "half hull", the plane of symmetry on a woodboard. So the DXF file is a half hull definition.
In DXF file, the XY plane is the plane of symmetry and also the work plane of the (future) CNC. I add extra lines to define bigger volume than the block of foam. I plan to machine plane by plane from high Z to Z=0 using a "pocket operation" inside ervery line.
Boat length is 1000 millimeter, line step on X axix is 1 millimeter (targeted accuracy), plane to plane Z axis is 10 millimeter to reduce file size.

Are my explanations clear ?
Do you think it's the right way ?
In CamBam a single "pocket operation" is very slow. Perhaps my DXF is to big.
Your feedback ?

Ecrou Papillon
Title: Re: CAM software
Post by: Gabriel on January 24, 2009, 10:49:33 AM
Wow! It looks like you've already gotten a really good start on this project. The DXF file looks really cool.
It's good that you're learning how to use the software first because, in my opinion, that's the hardest part of using a CNC. Building one is easy compared to learning the software.

I think what you're doing could work. It might take a long time to do it, but you?re headed in the right direction.

CamBam has to generate a lot of toolpaths for a hull as big as yours, and, as a result, it slows down the computer. There isn't really much you can do about it. What you could try though is to just do a few layers at a time instead of all of them at once.

For example, you could create several different CamBam files all from the same DXF. Each CamBam file might only have three layers, but ,after you generate the g-code, you can either just run each individual g-code file in the machine controller one after the other or you can manually combine the g-code in notepad.

It's also possible that each polyline is composed of too many individual segments. I noticed that I could zoom in on the curves as far as CamBam would allow, and still couldn?t see the individual lines. I don't know if there is any way for you to change that in the software you used to make the DXF, but it's something you could try. I'm not sure if it would make much of a difference though.

Those are my ideas.
You could also try and ask over on the CamBam forums. That's where the guy who wrote the software hangs out. His username is 10Bulls. If anybody knows how to make it work, it would be him.

I have attached the CamBam file that I was playing around with just as an example. I don't know if it will help you or not, but it might offer some insight. I used an oversized tool diameter to decrease the time it takes to generate the toolpaths. This would of course need to be changed though once you know what size bit your using.
Title: Re: CAM software
Post by: wing_nut on January 25, 2009, 10:01:08 AM
Hello Gabriel

Thank for your answer, help  and your .cb file.

I agree that CAM software is the most complex step in CNC. I need to improve my knowledge on it (Remenber my question in my first post : are tutorials available ?).

As we discuss using your forum, may I ask more information ?
Remenber I use the free release of CamBam Beta0.8 Rel2 for the following questions :

- How many time to process one pocket operation on your computer ? On my (old) computer (1GHz CPU, 1Gb RAM, XP) it takes about from 1 to 3 minutes.
System monitor shows 400Mb of RAM in use and 100% of CPU. Do I wait for a new computer at Christmas ? (11 months, rather hard)

- How to know the start point (and end point) of tool path of a pocket op. ? I don't split the layers in many files, because I think it's possible define the tool path from the end of a pocket op. to the next pocket op. I need to avoid any collision between tool and previous machined hull. How are transitions generated in CamBam ?

- In which order does CamBam write the machine op. in Gcode file ? If CamBam use the order of machining op. in left panel, how to move op. inside this panel ?

Ecrou Papillon

Title: Re: CAM software
Post by: Gabriel on January 25, 2009, 04:25:14 PM
Yeah, CamBam in particular doesn't have much in the way of tutorials. I know because I have looked everywhere and haven't found much. There are actually a few videos at this website that I just remembered  You should be able to find other CamBam videos by searching both and which may be of some help.

My computer has AMD dual core processor 2.80GHz and 4Gb of RAM.
Before starting to calculate the toolpaths for the pocket, it was using 50% of the CPU and 966Mb of Ram.

While calculating the toolpaths for the pocket, the CPU jumped up to 100% and 970Mb of Ram.
Having extra Ram in this case doesn't seem to make a difference. 

The amount of time it takes to process one pocket operation can differ greatly depending on what tool diameter you choose. I used the same .cb file I sent to you earlier which used a tool diameter of 50mm for the pockets, and it took between 10 - 20 seconds to generate a single pocket.

In CamBam plus (the version you have to buy) there is a little arrow which shows you where the pocket operation starts and finishes. I don't think there is a way to find it in the free version.

I'm not sure if I understood the rest of this question, so you might have to clarify it for me, but it doesn't matter if you split the layers into different files. The end result should be the same either way just so long you put run the g-code files in the right order. However, I actually found a better way to do it while timing how long it takes my computer to do a pocket. (I'm still learning this stuff too)

I noticed that it's possible to generate only part of the g-code by right clicking the pocket operation and choosing create g-code file. Do this for each pocket and make sure you run the g-code in order when you cut out your hull. Doing it this way might not be faster, but it's easier on your CPU. You can ignore what I said earlier about breaking the layers into many files. This way is better.

For your last question, CamBam creates the G-code in the exact same order that it appears in the left panel. If you want to change the order, right click the machining op and choose "move up" or "move down".

I hope what I said makes sense. If you have any other questions, let me know. I am interested in seeing how this project turns out.

I actually have a question for you. Have you used CNC machines before in your life? If not, you're learning really fast.
Title: Re: CAM software
Post by: wing_nut on January 27, 2009, 03:17:37 PM
Hello Gabriel

You wrote : I hope what I said makes sense.
Sure, your help is very usefull.

To process my hull , I'll try the following steps :
1- Generate all lines in CAD system
2- Export one line (one Z value) in DXF format
3- Load DXF in CamBam, generate toolpath, convert toolpath to geometry and export in DXF
4- If other Z value to procede, goto step 2
5- Load all DXF files in CAD, transform concentric toolpath to spiral (not implemented in free CamBam)
6- draw toolpath between spirals

As you says in a post, I'll register too in CamBam Forum.

Some news on my hull project : Now our modeler hobbyist group is working on electronic. We have done an electronic mockup for one motor and it works fine. Now we finish designing the electronic board for the three motors.
After, we plan to test accuracy on repetitive moves with a pen instead of tool and paper on workspace.
Then, we'll test cut off of some wood.
So, a lot of work before the first hull.

Your question : did I use CNC before in my life ? Never, I am not a mechanic. My previous hull is hand made. It has been difficult to do accurate and symetric shape. For the next hull, I try to move to CNC.

In your solar project page, I read longitude=87.55W latitude=43.18N. Internet says me that it is in Wisconsin. Is there pretty lake for model sailboat ?
Or do you plan to do sun observation in France ?

Ecrou papillon
Title: Re: CAM software
Post by: Gabriel on January 29, 2009, 04:03:37 PM
Sounds like you're making good progress with your CNC.

I don't actually live in Wisconsin; although, I bet that it would make a good place for a model sailboat. Of course, this time a year lake Michigan would have started to freeze over. It gets pretty cold up there.

In reality, I live just outside of Winchester Virginia, USA. I purposely chose GPS coordinates in the middle of lake Michigan because I didn?t want the entire world to know exactly where my house is to within just a few meters. Sadly, there aren't really any lakes around here, but there are a few decent sized ponds.

The sun tracking program I wrote should, theoretically, work anywhere, even France. I haven't tested it a whole lot yet though, so I can't be absolutely certain.

I haven't uploaded it to the site yet, but I've modified the program so that it will be able to reflect light toward a single spot throughout the entire day. Right now, I've been trying to get the new heliostat I've been building to work so I can test it out. I just finished attaching the motors today and will soon be trying to figure out how to best get the mirror attached.

Anyway, I hope everything goes well with you CNC and boat hull.

Take Care
Title: Re: CAM software
Post by: wing_nut on March 01, 2009, 01:49:17 PM
Hello Gabriel

I apologize for the delay ... a lot of things to do.

After we discuss how to interface a design to CNC program, I try some uses of CamBam. In CamBam, the problem is the large number of points in the current line of the hull (more than one thousand). This number of points is usefull in design for hull accuracy. But in CamBam, pocket MOP is too hard  and generate huge G-code file.

So I change the way to do. In my C program, I compute layer by layer to machine a half hull. One layer has a line corresponding to the hull (in red in the attached file). I add a second line as the toolpath along the hull (with the same accuracy and same number of points) and a third line equivalent to the pocket op (not in spiral, I don't know the english word, in french the name is "as a snake").
The program writes both the CAD file and the G-code file. The result is a lighter G_code file. The program is uncomplete, only area "under" the hull is processed, I will add an area in the "front" of the hull and an other in the "rear". I hope that I will soon generate the complete G-code file.

In the attached file, the layer names "Dxxx" are for red design lines and "Mxxx" are for machining lines.

Unfortunately our CNC machine is not yet finished. But I will post a picture of the first machined hull.

One more time, thanks for your help.

Ecrou Papillon
Title: Re: CAM software
Post by: Gabriel on March 02, 2009, 04:11:36 PM
Nice hearing from you again Ecrou , and don't worry about the delay. I understand completely as I'm busy myself right now.

The file you posted looks pretty cool, and it sounds like you came up with a clever way to reduce your G-code file size. 3D projects a notorious for their bulky files.  You sound like a computer wiz with the way you figured out how to make it output the G-code.

I'm sure it will look awesome once it's finished.

Talk to you later
Title: Re: CAM software
Post by: Davetech on June 20, 2009, 03:59:22 PM
I just stumbled across this:

It is about a free upgrade for the Diptrace pcb design program.

"The folks at DIPTRACE are offering a free upgrade to KICchip forum members. This is not offered on their website."

"Previously, the full function, free, non-commercial version, will do 2 layer boards of any size and up to 250 pins. The new upgrade will do 2 layers and 500 pins!"

"Note: this is a non-commercial version equivalent to the $145 DIPTRACE Lite. Non-commercial means that this is for personal use only--if you plan to make money on DIPTRACE created boards, then you must purchase the commercial license."

Title: Re: CAM software
Post by: Jon on August 14, 2009, 11:29:33 PM
That's a nice guitar and shape, Gabriel.  I once make an electric, but didnt use a cnc.  I used a bandsaw, but
as you can image I had to file the edge alot.  It was a single pickup one like you show there, Strat type, and had a
Les Paul hard/stop bridge and tailpiece, but I like the idea of putting the strings through the body.  The neck
was also cut as close as possible to the design with a small bandsaw [from Sears] and then a small xacto spoke shave [  Updated Aug 16-09: similar or exact to this: (  or ( ] and rasp [only initially to remove some good amts of wood, but can be omitted] was used to put the curve in the neck.  The neck was a glue up of 3 pieces wide of maple, and the body was a glue up of 4 pieces of maple.  It was playable, and I might have a photo someplace around here.  CNC is good and I think another method is with "shapers" or something which is a routing method that follows a pattern.   I wish I could keep doing that, it's real fun to make something like that.   [UPDATE Aug. 20-09]  I know that this post was a bit off topic but since we all love wood and music (and tools such as CNC, etc), it might be a good post.  Here is a YouTube vid to watch that shows an example:  watch?v=ZL6-LmYjwe0    Though his spokeshave is a bit bigger and maby a different design, but the ovearall method is the same.
Title: Re: CAM software
Post by: Gabriel on August 15, 2009, 11:25:38 AM
Yeah, it's definitely fun, and it's cool that you were able to make your own guitar. Not many people can do that sort of thing.

My own woodworking skills leave much to be desired, so my guitar project was pretty much doomed from the start, even with the CNC machine doing all of the work.  :)

One day, I would like to take another stab at building a guitar, but, for now, I guess there are better things that I could be working on, like finishing my heliostat. I might have the array finished today, but we'll see how it goes.

I'm still thinking about that solenoid idea too. Once I'm finished with the heliostat array project, I think that I might try making one. The tricky part will be getting it to reverse direction. At least the electronics should be fairly simple though. (Hopefully)

Title: Re: CAM software
Post by: Jon on August 28, 2009, 06:43:37 PM
I'm not sure about  how to reverse the direction of a wheel/gear with one solenoid, but it's possible that another solenoid can be used for that purpose.
Title: Re: CAM software
Post by: Gabriel on August 29, 2009, 04:41:04 AM
Yeah, I also think that it would take two of them, or maybe one that can somehow move in two directions. Of course, that would be more complicated.
Title: Re: CAM software
Post by: gocnc on October 12, 2009, 08:07:10 AM
I just installed Freemil
It is a free software without any support, they say there is a yahoo group.
If anyone know a place I can go for help that would be nice
I just opened an stl file with it
I am thinking about using this one of the smaler machines I would like to make
It does not look user friendls and there are no tutorials

If I can prepaire everything with cambam and then transfer the copies to freemil.
But it really is the pits the way the program is the interface is not good.

One thing about these CAM programs
So far I know how to go from CAD to CAM
How about from the CAM to the cnc machine
I guess when I have the machine all set up things will get clear

So tell me what you guys think about this freemil
Title: Re: CAM software
Post by: Jon on October 12, 2009, 02:15:06 PM
gocnc, this site, one of many devoted to free CNC,  looks like it has tutorials on free CNC software, and it mentions FreeMill: (

I also seen the FreeMill program download on this site, but I have no idea if it includes any tutorials: (
Title: Re: CAM software
Post by: wing_nut on September 11, 2010, 01:22:45 PM
Hello Gabriel, hello to all

After talking about my hull project for model boat, on january to march, 2009, I had a lot of work to set up the CNC.
But today, I machined the first hull in foam (see attached pictures).
It is a "half hull"1 meter long. The tool path gap is 1 millimeter.

The aim of this post is to thank all CNC folks who helped me on machine building and software processing.

I hope to send next post with a picture of a ready-to-sail "full" hull.

Ecrou Papillon
Title: Re: CAM software
Post by: Gabriel on September 11, 2010, 03:06:42 PM
Very cool!

I'm glad to see you manged to do what you wanted, and I'm sure that this wasn't an easy project to finish.

It will be neat to see it once it's in the water.