more cnc Q.

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MCRIPPPer

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ok. i want to start collecting parts for a cnc conversion of minimill. i want to start with the computer. looking on best buy i can get refurbished computers for $150 or so, running windows 7. thinking i will go for mach3 software and a usb control device. is it ok to run CAD on the same computer that controls the machine? i have been playing around with freecad and like it so far. what is a usable free or cheap CAM software?

i cant seem to find any computers with a parallel port, so i guess im stuck with usb.
 
There are still some computers out there with a parallel port, I just bought a used laptop ($139) the other day that has one for that very purpose. I just called my computer guy and told him what I needed, and said go find it. You just have to look at the mom & pop computer shops. Failing that, there are add on parallel port cards available for cheap. Goodwill and Craigslist are another resource. My preference is a laptop because you have everything in a small package.

There is no reason that you can't run Mach3, CAD, and a CAM program on the same machine, just not at the same time. Mach3 does not like to be disturbed when running.

For a CAM program my preference is CamBam http://www.cambam.info/ Free to download, with 40 free full featured runs, then reverts to 500 lines until you buy a license. $149, they also have an older completely free version. It plays well with Mach3.

There is also open source software available, but I have no experience with it. Linux CNC is one open source software that comes to mind, and there is free CAD and CAM software out there.

When you get ready to buy the motors and drives, Amazon and Ebay both have a number of CNC kits available at reasonable prices.

I hope this helps.
 
thanks.

im wondering if it is worth it to just pay the 150 or so for a usb type driver board and avoid weird issues with mach3 getting interrupted? (thats what i hear at least, that usb does not have that issue) anyone have experience with mach4?
 
is it possible to run both a mill and lathe (at different times) on a single computer with mach3? im guessing i would need two breakout board setups.
 
Absolutely possible. The breakout boards normally come with the motor kits.
 
MCRIPPPer said:
ok. i want to start collecting parts for a cnc conversion of minimill. i want to start with the computer. looking on best buy i can get refurbished computers for $150 or so, running windows 7. thinking i will go for mach3 software and a usb control device. is it ok to run CAD on the same computer that controls the machine? i have been playing around with freecad and like it so far. what is a usable free or cheap CAM software?

i cant seem to find any computers with a parallel port, so i guess im stuck with usb.
Click to expand...

Shouldn't be too hard to find a decent computer with a parallel port for around that price that will run LinuxCNC / Mach3-4. If your thinking of LinuxCNC I would shy away from laptops.

If your going to use a 2D CAD program, most any computer will do. However, if your thinking of a 3D solid or polymesh CAD, you will almost need a computer with OpenGL capabilities, (3D video card/chip).

As for usable free or cheap CAM? In the free arena, there are a number of 2D CAM programs and plugins, like the CAM plugin for Inkscape, and even browser based CAM like MakerCAM. For 3D maybe the best you'll find today would be PyCAM, though you will be looking for your 64 node Beowulf cluster to run the thing on once you start trying to do 3D follow contour paths. It is not known for it's speed.

I say today, as some of the developers of the mentioned FreeCAD are working on a Path module that should be very fast in it's computations and work from true solids (instead of meshes), but like most everything FreeCAD, it is being developed by very talented volunteers in their spare time and it will be done when it's done, and not a moment sooner.

In the "cheap" or inexpensive, category there is CamBam, (already mentioned), that is very popular and capable as well as the slightly more expensive MeshCAM (which I like). There is also Estlcam which also falls well into the cheap category.

Machine control - of course there is Mach3/Mach4 and LinuxCNC, but there is also grbl which runs on an Arduino and uses a USB input and takes the Gcode streamed to it from programs like Grbl Controler if you want to go the bare bones / dirt cheap route. The up side of Grbl Controler is that it will run on a Raspberry Pi or Beaglebone just as well as it will on a high powered desktop.

Anyway, some things to think about and there are plenty of options out there.

Mark
 
Instead of USB take a look at Ethernet. Very fast and stable.

Ray
 
thanks guys. thinking of cambam with mach 3 would work well for me and still cheap enough.

is it a bad idea to leave the stock leadscrews in my machine for now? i would just have to make sure to conventional mill right?
 
MCRIPPPer said:
thanks guys. thinking of cambam with mach 3 would work well for me and still cheap enough.

is it a bad idea to leave the stock leadscrews in my machine for now? i would just have to make sure to conventional mill right?
Click to expand...


Conventional mill, yes You can use the stock leadscrews, it just won't be quite as accurate as ball screws, also you will need to program in the backlash compensation in Mach3. I would also go with higher end of the torque range motors in the NEMA 34 size because the acme screws have much more friction than ballscrews.
 
You can check out Autodesk Fusion 360. It's what I use for CAD and CAM. Well, I've at least played with setting up the CAM. I haven't used it quite yet on my CNC that is not complete:shush:. You should be able to register it as a hobbyist and use it for free.
 
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