How to play with EMC2 and G code without an actual mill

I would like to somehow practice EMC2 (milling application, 3 axis), and G-code and other such things, without actually running a mill. It
would be a "simulation". What kind of software can I use.
Ergo, say, if I could specify the tool geometry, location, raw material geometry and location, then applied G-Code, I want to see what I would end up with AS IF I machined it.
Any suggestions?
Preferably Linux
thanks
i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 02 Mar 2010 11:30:51 -0600, Ignoramus5280

Ig, there are demos in there you can modify, I think. I know I've run the demos. You do have to load the RTAI version of the kernel.
Pete Keillor
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

OK, I will look some more. I am about 1/3 through the EMC2 manual, which is actually very well written. This EMC2 looks like a fine piece of software also.
I was hoping to use it in simulation mode without RTAI mode on later versions of Ubuntu, this way I can try it on many computers, like my laptop.
Or maybe I will just run it remotely via ssh.
i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 02 Mar 2010 11:43:14 -0600, Ignoramus5280

IIRC there are some Yahoo groups .... http://groups.yahoo.com/group/jobshophomeshop / http://tech.groups.yahoo.com/group/emc_list / http://tech.groups.yahoo.com/group/emc_list / http://groups.yahoo.com/group/ABQMachine /
I think there is a mailing list too ....
--
Cliff

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Pete Keillor wrote:

The Axis GUI of EMC2 has a 3D TOOLPATH preview. But, this is not a subtractive volume viewer, ie. it does not show you what the machined object will look like. If you are familiar with milling, it gives a pretty good idea of what you will get, but if you want to evaluate the effect step-over size has on cusp size of a contoured surface, you will never get that info from EMC2. What you need is a previewer that is provided by the high-end CAD/CAM packages like Gibbs CAM or others. Prepare to mortgage your house for that investment.
Jon
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Maybe I will write a free, GPLed previewer. It does not seem to be monumentally complicated, given enough RAM.
i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Please get started. That piece of software is missing from the open source world.
Seriously, by the time you understand what you need to know to write it, making things out of scraps of metal using a CNC will be childs play.
Go Iggy Go!
Wes
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I was thinking of something very simple.
Take the raw piece of material to be milled. Represent it as a collection of points on a 3D grid (most likely a rectangular set, as you normally start with a steel rectangle). When the milling bit goes through its path, every point on its path is removed from material, and this means it is removed from the set of points that we began with. We will end up with a set of points at the end that, if displayed properly, would visualize the remaining piece.
i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Look up cutter compensation left, cutter compensation right.
http://www.stanford.edu/group/prl/documents/pdf/cuttrcmp.pdf
Then consider it when cutting a radius.
Wes
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
    [ ... ]

    Hmm ... what resolution were you thinking of? With a resolution of 0.001", that is 1e9 points per cubic inch (times the number of bytes per integer in that CPU), so my Bridgeport, which will handle 12" Y, 18" X and 5" Z (not counting knee height moves), so 1.08e12 data points worst case.
    Cut it down to a resolution of 0.010" and you get a much smaller data set -- a total of 1.080e9 and assuming four bytes per integer (32 bits) that would be a mere 4.3 GB of data space. It might keep your swap space rather busy for a while, depending on physical RAM in the system, but it looks doable. I would suggest using a third program to actually display the results -- perhaps something like gnuplot could do it. Once it is configured into a surface, you could probably turn it into a sparse matrix to save space, especially since gnuplot would not need to display the internal points.
    Enjoy,         DoN.
--
Email: < snipped-for-privacy@d-and-d.com> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

You can be smarter about data storage, since in most cases data is contiguous (you cannot mill out a sponge). So you can store an enumerated value about each cubic millimeter, one out of three values: 1) Material was not removed 2) material was partly removed 3) material was removed fully. For cubic millimeters that are 1 and 3, no further storage is necessary. For cubic millimeters that are number 2 (partly removed) you can store further details. 8,000 _bits_ per cubic millimeter would cover it in great detail of sub-cubes of 0.05mm step.
If, say, 1,000,000 cubic millimeters are in state 2 (1 square meter of surface), then we need 8,000*1,000,000 bits, or 8 gigabits, or appx. 1 gigabyte. Memory access structures and such will always add some memory need. But it seems not to be excessive.
Since this is done mainly for GUI display, extreme precision is not necessary.
Let me know if my math is wrong.
i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Ignoramus27796 writes:

Your math is known as voxels. This has all of course been researched and developed for decades. No need for you to reinvent it; just study computer graphics and modeling, and computational geometry. If you're not a computer scientist, then it doesn't get easier pretending it is not computer science.
A quicker approach if you're trying to develop this yourself would be to use solid models, and write just a translator to parse and convert the G code semantics into the equivalent 3D solids representation. Then you can just feed the resulting shapes and add/subtract operations into a solid modeler, and you have escaped all of the hard work, and get all the rendering and drawing generation for free.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 04 Mar 2010 09:52:30 -0600, Richard J Kinch

If you were to generate STEP, SAT, or IGES files you'd have the option of using one of the free 3D CAD viewers in addition to most any solid modeler.
--
Ned Simmons

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

    [ ... ]

    O.K. Smarter about the storage, but much greater complexity in storing and accessing it. This will probably slow down the construction and the readout of the data.

    Your math looks good -- and I suspect that really we only need a resolution of 1mm, not 0.05mm -- except when displaying a very small workpiece, in which case we will be working with tiny milling cutters as well.
    If you do this -- I hope that it is X11 based, and does not use any of the weird linux-only features of the OS.
    If you need someone to compile-test it on a UltraSPARC Solaris system, I would be willing to do this.
    Enjoy,         DoN.
--
Email: < snipped-for-privacy@d-and-d.com> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 4 Mar 2010 04:44:50 GMT, "DoN. Nichols"
<big snip>

Grace maybe be able to do this too, see:
http://plasma-gate.weizmann.ac.il/Grace /
"Grace is a WYSIWYG 2D plotting tool for the X Window System and M*tif. Grace runs on practically any version of Unix-like OS. As well, it has been successfully ported to VMS, OS/2, and Win9*/NT/2000/XP (some minor functionality may be missing, though)..."
Just happened to come across it yesterday while running down applications that might be useful.
What you are trying to do is very similar to terrain mapping. You maybe able to modify some of the software utilities that are used for importing elevation data. They normally accept something like csv with lat, long, elev data.
Just some wild ideas to ponder...
--
Leon Fisk
Grand Rapids MI/Zone 5b
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Conceptually, yes. As a practical programming exercise, you pretty much need to come up with a much more efficient representation.
--
As we enjoy great advantages from the inventions of others, we should
be glad of an opportunity to serve others by any invention of ours;
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Ignoramus5280 wrote:

FYI, what you're looking for is really a CAM simulator, not CNC control like EMC2.
I haven't played with EMC2, but I expect that it's like Mach3 and defaults to a "demo" mode, i.e. a configuration where it isn't expecting feedback from an actual machine so it can run "blind" with no machine connected.
I'm sure EMC2 will show you the toolpath movements when running and the toolpath simulation, since EMC did and Mach3 does. The CNC control toolpath simulation only shows you the moves, it does not attempt to show anything relating to the cutter geometry or the actual material being machined. I believe most CNC controls are that was since the cutter geometry is the domain of the CAM software that is generating the G code, not the domain of the CNC controller.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

There is a live CD for EMC2 that will let you boot and run EMC2 in demo mode from the CD without installing it. At the time I was converting my mill, PIII's had some of the better scores on latency tests, so I bought a PIII 800mHz on eBay for ~$35 with ~$35 shipping, that's my $70 EMC2 controller.
When I first bought my CNC mill I bought Bobcad/cam V17 and have since upgraded to V21. It lets you draw the part, generate the G code, and run the code giving you a 3D view of what it cuts. You can download a demo of BobCAD/CAM from their website but their salesmen will call. If you tell them you're just using it for hobby use you might be able to get a cheap price on it. There are also some free viewers I've seen years ago but haven't looked lately.
RogerN
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Can't help ya there, but I hear a good firewall for linux is vinnywall 1.0
http://www.derkeiler.com/Newsgroups/comp.security.firewalls/2002-10/6957.html
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 02 Mar 2010 11:30:51 -0600, Ignoramus5280

===========Take a look at http://www.cncsimulator.com /
price is right [free] Runs in windows.
also see
http://www.youtube.com/watch?v=T4tH_UQWw-Q
http://www.cnczone.com/forums/archive/index.php/t-28790.html http://www.cnczone.com/forums/archive/index.php/t-11895.html http://appdb.winehq.org/objectManager.php?sClass=application&iIdQ15 http://www.brothersoft.com/downloads/cnc-simulator.html and many more
Be sure and let the group know what you find.
Unka George (George McDuffee) .............................. The past is a foreign country; they do things differently there. L. P. Hartley (1895-1972), British author. The Go-Between, Prologue (1953).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Site Timeline

  • - the site's newest thread. Posted in

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.