Getting my feet wet.

[thegomicat]

I recently came upon a PM25MV mill with an Arizona cnc kit already installed. My budget will pretty much only allow for the mill as it is converted. They have some very good motors and an Centroid controller kit and pendents which I also do not plan to get as it would be another couple grand I don't have at the moment, but the machine itself seems solid. I guess my question is since I only want to start out with some basic cnc controls, would something like an arduino with a cnc shield like this https://blog.protoneer.co.nz/arduino-cnc-shield/ be able to work a 3 axis mill fairly well if not basically? Should I be looking at something that deals with cnclinux instead like a rasp Pi version instead?

My initial plan was to start with a manual lathe and then convert over to cnc when I had more funds but seeing as this is already partially there and not really super feasible to undo as the owner no longer has the manual wheels (or is it?), can I get the rest of the way with some steppers, drivers and a power supply (closed looped if needed, regular if fine for basic "student level" learning ) with a few self made knobs? It appears like what I linked might work with a basic program that sends gcode to the ardunio then off to the motors? Is this fairly correct so long as it has some proper drivers (compatible A4988 chopper drivers) ? Is this something better asked on the ardunio forums or how succesful have people been converting benchtop mills to cnc with some simple and lower cost options like arduino units? Thanks!

 

[matthewsx]

Hello and welcome,

I'd say your initial plan is solid and honestly a very good way to start. Running a small manual lathe will give you an understanding of materials, feeds and speeds, and limitations with rigidity that can cost a awful lot with any CNC machine.

If the seller wants to part this machine out there may be a very good reason. I personally wouldn't touch a CNC that only had some of it's components without a substantial discount. It's hard to give any advice without pictures and asking prices but if this is your first machine tool I'd suggest getting it complete and working or passing it up. Used CNC components (sounds like the controller and pendant were originally part of it and the seller is trying to recoup their cost) aren't worth anything near what their original price was.

Take your time and learn everything you can before buying your first machine. It likely won't be your last but you don't want it to slow you down unnecessarily. If you really want to learn CNC first, there are online simulators you can try out.

If this particular machine is too good a deal to pass up, you can source a cheap controller on Amazon or eBay and run it with Linux CNC for very little money. But, if the original builder decided to go with Centroid you'll need to know if choices they made will limit you as to what hardware and software you'll be able to use.

Proceed with caution here, patience is your friend.

John

 

[Nutfarmer]

Be careful of buying someone else’s project. You may be buying someone’s headache. Parts could be missing and hard to find. Only touch if at a giveaway price.

 

[markba633csi]

I think the Arduino might be too limiting and slow- the rasp/ linux cnc would be better
BTW the DRV8825 driver chip is even better than the 4988

 

[thegomicat]

Hitting the spam filter with a long winded reply, see if we can't get that helped, but in the mean time I appreciate everyone's advice and cautioning. Hmmm I shall have to look into the options for the rasp and linuxcnc, I did see what appeared to be very similar looking boards... I am not sure if they are more just "wiring in the right spots, connect to pc and off you go!" or also would require programming (beyond things like gcode or modern methods). But I can't say I would hate a computer program that would let me 3d model lo, may be asking way too much there).

 

[dabear3428]

the cheapest and most rewarding (depending on how tech savvy you are) is LinuxCnc and an old surplus computer with a parallel port and a $10 BOB. read thru the LinuxCnc wiki for the list of known computers that work well with linuxCnc. this also allows you to leverage your learning with LinuxCnc / Linux because i cannot think of anything that you cannot cover CNC wise with Linuxcnc and Mesa cards.

 

[dabear3428]

If you set up the computer to dual boot windows you can get fusion360 for free (that is what I use) but I think that there are some free Linux cad/cam softwares that are free, the great thing about Linuxcnc is the available knowledge base.

 

[thegomicat]

the cheapest and most rewarding (depending on how tech savvy you are) is LinuxCnc and an old surplus computer with a parallel port and a $10 BOB. read thru the LinuxCnc wiki for the list of known computers that work well with linuxCnc. this also allows you to leverage your learning with LinuxCnc / Linux because i cannot think of anything that you cannot cover CNC wise with Linuxcnc and Mesa cards.

I have been doing a little research the last few hours in terms of it running from a rasp pi, and ive seen some people go nuts which was intimidating, but then I say a guy with a pi, 4 drivers, which I assume were all connected to motors and power supply... and probably a controller of the type you mention. He then screen cast from his laptop to the rasp pi, which would give a little delay depending on how close you are to it, but it seemed pretty cool. And I am already a fan of linux, so it might not be as hard for me maybe as some folks going in 100% blind. Do those mesa cards come back in stock often (if I was looking at the right brand card anyway). Everything seemed out of stock

 

[thegomicat]

If you set up the computer to dual boot windows you can get fusion360 for free (that is what I use) but I think that there are some free Linux cad/cam softwares that are free, the great thing about Linuxcnc is the available knowledge base.

Def computer savy up to a point (build them, and install, or change OS's randomly and frequently to play around. So that sounds fun too!

 

[dabear3428]

I have been doing a little research the last few hours in terms of it running from a rasp pi, and ive seen some people go nuts which was intimidating, but then I say a guy with a pi, 4 drivers, which I assume were all connected to motors and power supply... and probably a controller of the type you mention. He then screen cast from his laptop to the rasp pi, which would give a little delay depending on how close you are to it, but it seemed pretty cool. And I am already a fan of linux, so it might not be as hard for me maybe as some folks going in 100% blind. Do those mesa cards come back in stock often (if I was looking at the right brand card anyway). Everything seemed out of stock

you do not need any mesa cards to bo basic LinuxCnc thru a parallel port, I do not use the raspberry pi cards but they show 49 of the 7I90HD cards available, in general cards come and go into stock frequently at MESA. do your research but i think you can get there with a surplus pc and one of these:

Amazon.com: TwinkleBay Connector Db25 D-sub Female Plug 25-pin Port Terminal Breakout PCB Board : Electronics

Buy TwinkleBay Connector Db25 D-sub Female Plug 25-pin Port Terminal Breakout PCB Board: Connectors & Adapters - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

no need for the raspberry pi to slow things down just cpu to stepper drivers, check that the PC can keep up but there is a large knowledge base covering this on the Linuxcnc site.

i'm currently working on an analog setup to drive oldschool DC analog servos and it is amazing how much capability Mesa brings to the table for things like that, but in the basic form you do not need anything at all if you want to build your own BOB. I chose not to go that route because of the level of my build but i picked up all that i'm passing on to you while researching the Acorn/Messo/LinuxCnc options and if you are willing to get your hands dirty LinuxCnc offers a lot for very little and i cannot see any limitations for scaling up.

BTW there is nothing wrong with the Messo or Acorn solutions, they are more of a financial commitment but very capable especially for someone who doesn't want to dink around with configuring hardware, which you sound like you enjoy Soooo.