Newbie in the CNC world.

[Wulffdk]

Hi everybody.

I'm totally new to the CNC scene, but have decidede that i want to build a 3 axis CNC milling machine. I have got a friend of mine who works with automation in his daily work to help med building the mechanics, but i dont have e clue as where to start with Software etc. I'm a electronics technician my self af have been giving som ethougt to making all the electronics my self. My plan was to go with a PIC-USB µcontroller. But my problem is that i dont know what data it has to be able to interprete to motion.

So my rather comprehensive line of questions are:

• What PC based freeware "CNC" applikations are good? need to be able to create routing from CAD drawing.
• What kind og data does the applikation actually send to the electronics in the router and how much data does it send?
• What type of motors shall i be using? sevo/stepper?
• Anybody got schematics for at motorcontroller i can build my self, or is it advisable to buy a controller?
• Is it possible to get a complete "blueprint" for at router capable milling in aluminum, for free og cheap somewhere?

I am in the process of gathering materials, aluminum profiles for framing and ballbearing spindels for linear motion(from an old SMT machine)


I have been trying to search through the forum, but since i dont have the knowledge about what to search for, i haven't had a lot og luck... hope someone on this super forum is able to guide me in the right direction...

[springlakecnc]

Hi,

I have been into retrofitting cnc for about 20 years now.

Yes, you can build a cnc control, and get alot of info from this site. Be prepared, you will find most of the manuals for break out boards and axis drives, etc, are written for an electrical engineer, not a machinist.

If you have plenty of time to invest, then continue on. If you just want to get the machine running, look at websites like "Machmotion" (they advertise in this site), or Ajax cnc, and there are others. These controls would have some build to them, but the engineering is all done, and they sell you components that all work together.

I would say, you can build from scratch for about 2/3 the price of what these guys charge, but you could save 100-200 hours of your time doing research, and ordering things from many different sources, and figuring out why something don't work. Believe it or not, there are people that start to build a cnc, and never finish it for different reasons, like the number one reason: "I can't get it to work".

Just stick with this site, and friends will help you get yours running!

Put in a description like: I need help sizing axis drives and motors for a Cincinnati 20hc2000, 100" x axis by 60" y axis travel with a 20hp spindle motor, and cat 50 tooling, OR a little 10"x5" travel table top mill, with a 1/2 hp spindle, etc. Always put in as much info as you can, so someone can help you.

Also, you get what you pay for, like you want free blueprints to build a router, ok, what size servo motors do you need for it? If you buy plans to build a router, i think "Campbell Designs", Bob Campbell, sells plans to build a router, and i'm sure there are many more, Bob would tell you what size motors will work well.

The point is, you will eventually have your cnc machine running, its a question of: do i invest time, or money!

A couple of answers to your direct questions:

Check out Artsofts Mach3 software. As far as i'm concerned, its the best value in the universe (and maybe farther) For running a "step and direction" pc based control.

Servo or Steppers: Stepper motors are way slower, way cheaper, almost or no tuning, and way easier for a novice cnc builder to deal with. Servos have a closed loop system, are bigtime faster, and need motor wiring AND encoder wiring. I would say if this is going to be a hobby machine, i would lean tward the Stepper motors , if its going to be used commercially, where someone needs to get paid to run the machine, go with DC servos, for bigtime production, go with "Brushless" servos.

Schematics for a motion controller? a windows xp computer with Mach3 software makes a good controller. Data to controller?: the computer sends "Step & Direction" signals to a breakout board, that has the wiring terminals, to run to the axis drives, the drives take it from there. (you dont need other circuit boards or a motion control board)

Buck
Spring Lake cnc llc

[Wulffdk]

I have now been looking a bit on MACH3 and think it looks super nice. However i stille think that to throw 150-200$ in software before i have any HW isnt so interesting.

I have decidede to use steppermotors and have now focused my search for at steppermotor driver(breakout board). Can it really be that a schematic is which uses a parallel port for input from the PC? anybody got any plans lying aorund i could get a copy of perhaps?(legit offcourse)

I would just like to try to build something myself at first and if taht goes south i would have to buy a controller for the steppers.

Does anybody have any input on choosing unipolar og bipolar steppers?? any advantage/disadvantages?

Does applikations like the MACH3 send automatically via the parallel port? and does anyone now exactly what lines of data it sends? I have a operating PIC18F4550 µP board and if the PC application "only" sends textstrings to the PCB i can handle that data easily. and I assume the motors only will need a super short pulse to step once?

[Kelinginc]

This will help you, you can build this from this package
sample: http://www.kelinginc.net/PackageAssembly.pdf
components: http://www.kelinginc.net/ThreeXCNCPackage2.html
Wiring Diagram: http://www.kelinginc.net/KL-4030Wiring.pdf
Ready and Plug Controller: http://www.kelinginc.net/ControlSystem.html

[Wulffdk]

I'm soryy but if i didn't express myself clear enough what i meant was. I would like to fine schematics for at stepper motor controller i can build myself, not just buy a kit and wire them up(not yet anyway, i may end up doing that when my frustrations overpower me).

[samco]

Take a look at emc2 - open source/free.

http://www.linuxcnc.org/
http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl

[samco]

THis is a decent stepper driver with current limit.

http://www.pminmo.com/l297-8/l297-8.htm

sam

[Wulffdk]

Originally Posted by samco THis is a decent stepper driver with current limit. http://www.pminmo.com/l297-8/l297-8.htm sam

Hi Sam.

that controller looks nice. Is it possbile to build 3 of theese an connect them all up to the parallel port at the same time, so they are controlled simultaneously? and is it possible to run theese 3 drivers directly from a CAD applikation or do i need some sort of translator installed on my PC before it will work?

[samco]

yes

that controller looks nice. Is it possbile to build 3 of theese an connect them all up to the parallel port at the same time, so they are controlled simultaneously?

and is it possible to run theese 3 drivers directly from a CAD applikation or do i need some sort of translator installed on my PC before it will work?

Normally it is like this...

Cad (autodesk, alibra, solidworks, whatever) -> Cam (cambam, camworks, bobcam, virtual gibbs, whatever) -> Machine Controller (cnc) (mach/emc/turbocnc/whatever)

Some combine cad/cam or cam/machine controller... but for the hobbyist you will probably have separate applications for each step.

for machine controller - I will say again that you can't beat emc2.

sam

[Wulffdk]

Originally Posted by samco yes Normally it is like this... Cad (autodesk, alibra, solidworks, whatever) -> Cam (cambam, camworks, bobcam, virtual gibbs, whatever) -> Machine Controller (cnc) (mach/emc/turbocnc/whatever) Some combine cad/cam or cam/machine controller... but for the hobbyist you will probably have separate applications for each step. for machine controller - I will say again that you can't beat emc2. sam

Thanks a lot Sam. once again youre answer is super..

The link between the different applikations used in the CNC process suddenly makes a hole lot of sense. I already have acces to a autodesk machine så thats out of the way. so now ill just try and DL cambam and se if i can get a machine up and running with EMC.

I have also found a guy who lives 10 miles from me who have experience with building his one CNC router for wood, so hopefully i can pay him a visit and gain a little intel from his project and pick his brain for good ideas.

More questions will probably find its way to this thread.

but anyway a lot of thanks for the usefull replies..


Wulff

[Richster]

Hi Wulff,

I don't know if this has already been mentioned (couldn't spot it) but Mach 3 is free to download and use, but limited to 500 lines of GCode. There's plenty you can do with that limitation to get your machine up and running, particularly if you want to do your own coding rather than using an automaed CAM solution. I made many bits for my current machine by coding manually, long before I bought the Mach3 licence. Having the licence allows me to use other applications to produce more complex GCode to cut non-circular curves, 3D parts etc.

For cutting 2D parts from CAD plans I can recommend Cut2D from Vectric (UK based). It's not free, but much cheaper than many of the other software solutions out there. I use this to convert AutoCAD drawings into GCode, which then drives Mach3. You probably would need the Mach3 licence too since you'll hit the 500 limit quickly with all but simple jobs. There's also LazyCAM which ships Mach3, but there is an additional licence to enable all the functionality in that.

Good luck....

[Wulffdk]

It sounds super that a "trial"/limited edition of mach 3 is available. My plan is to use Inventor, that can be used a substitute for AutoCAD right? or du i have to use an AutoCAD?

Can i then import it directly into Mach3? Mach3 is a CAM/Machining combo right? Or do i have to use ex. CamBam to convert the files before i import them into Mach3?

I will at forst start by making VERY simple shapes just to get tha hang of it before i need to do anything more advanced than squares etc.