CNC Plasma build - stepper motors and electronics

[Squickmon]

hi,

Im new to this whole blog thing. Im interested in building a cnc plasma table and have been researching it for about 6 months now. Im looking into buying the electronics and stepper motors. I've been on ebay a lot looking at different types, but i just cant decide because i have no prior knowledge on any of this cnc stuff. I have been welding for the last 10 years and i just purchased a spectrum 375 a year ago but its really hard to work freehand. I don't think i will have a problem building the table at all, but im just wondering if there are certain types of motors which are better then the others, or that are just more compatible with different software. this is going to be my first table so im planning on building it and using it for a year or two then rebuilding it and saving the motors and software, so im just trying to get some good stuff. Does anyone have any suggestions?

thanks
Simon

[diyengineer]

Kelinginc.net

They offer steppers and servos. You could easily use steppers and be fine. Cnc plasma tables dont need a lot of TQ like a mill does. You could use servos too though if you want to be able to use them for say a mill in the future? It all depends on the weight of your gantry, your gearing, pulleys, etc etc..

[millman52]

Probably the easiest way to go by far is a kit from WWW.CandCNC.com Everything is matched & comes with Mach3 license. Add to that you have support after the sale.

A torch height control is almost a must for plasma use on a CNC table.

Be sure when comparing prices you do the best you can to include everything. Wiring, micro switches, motor cable, cabinet to install your machine controller, etc. etc. All of that is included in one of CandCNC kits. When you include all the extras & take into consideration most everything is pre wired the price isn't bad at all.

[Squickmon]

what are the best brand of stepper motors to buy? do they all have the same types of plugs to plug into the main computer? how do i know which type of computer to buy? what are decent brands that will last?

[diyengineer]

Kelinginc.net has the largest selection of DC servos and DC steppers. Everyone seems to like there quality and craftsmanship. As for electronics www.cnc4pc.com is one of the better places to buy the breakout boards etc. As for drivers you can either go with gecko or viper (they both are the 2 larger names of many).

[millman52]

what are the best brand of stepper motors to buy? do they all have the same types of plugs to plug into the main computer? how do i know which type of computer to buy? what are decent brands that will last?

Stepper motors do not usually have plugs on them. Most common you will find 8 wire motors that you can wire series or parallel depending on the drivers you chose to use. Besides it's probably best if you don't have plugs at the motors as that is just another place for corrosion or loose fitting connections to cause you a problem.

As for a computer about anything windows XP with 1.5GHz processor speed & 512 memory should be more than adequate.

The motors connect to your drivers of choice. The drivers to a power supply of correct size & Break Out Board (BOB) of your choosing. Then on to your computer. Depending on power supply & BOB you may need seperate 5V & 12V supplies.

This still isn't all the system. you need connections for Limit, Home, & Estop switches.

[diyengineer]

Stepper motors do not usually have plugs on them. Most common you will find 8 wire motors that you can wire series or parallel depending on the drivers you chose to use. Besides it's probably best if you don't have plugs at the motors as that is just another place for corrosion or loose fitting connections to cause you a problem.

As for a computer about anything windows XP with 1.5GHz processor speed & 512 memory should be more than adequate.

The motors connect to your drivers of choice. The drivers to a power supply of correct size & Break Out Board (BOB) of your choosing. Then on to your computer. Depending on power supply & BOB you may need seperate 5V & 12V supplies.

This still isn't all the system. you need connections for Limit, Home, & Estop switches.

the computer MUST have a parallel port too!! (unless you use a smooth stepper board, which converts the signal to USB output). Most newer computers don't have parallel ports (you can always use a QUALITY PCI/PCI-E add in card)

What i found helpful was to use microsoft paint and draw out your stepper motors, then draw lines to your drivers, then from the drivers to the breakout board, then to you computer and power supply, limits/homes, estop, relays etc.

This web will make things much clearer and then you can also just use the text option to right down part numbers below. It will make the overall process much easier to visualize.

[diyengineer]

http://www.hobbycnc.com/products/hob...oard-packages/

There is a FULL kit. At the bottom select 4 axis and 4 305Oz steppers and your good to go (even if you don't use 4 axis's now it will leave your options open). you will have to buy a transformer from the link provided, as well as a case separately. I purchased the kit and it worked wonderful, along with GREAT email tech support and a forum full of help.

[nomedia="http://www.youtube.com/watch?v=-w5pCUCzs3U"]YouTube- 4 Axis CNC mill stepper test using Mach 3[/nomedia]
Above is the video of the 4axis kit and board using mach.

You have to solder the board together, and assembly is required. good thing the directions are REALLY good.

That got me going from nothing to a fairly good understanding of the whole process. Without that kit i would be 100% lost haha.

[millman52]

You are correct DIYengineer. I'm still not used to PC's not having a parallel port anymore. Even so I probably wouldn't buy new PC for the CNC table anyway. I'd look for a Pentium 4 class or equivalent AMD with 1.6-1.8 GHz processor with XP Pro & a CD or DVD drive. Most anything of that vintage will have a parallel port.

A refurbished PC of that basic design can be picked up for less than $100.00

[diyengineer]

I picked up a gateway, that has a pentium 4 1.8ghz. Upgraded the ram to a gig and it has 40 gig hard drive. It runs windows xp REALLY FAST. I picked it up on craigslist for 50 bucks, and bought the ram at a local pc shop out of a bucket of used ram (cause its so old) for 5 bucks!

Works like a charm!

You are correct DIYengineer. I'm still not used to PC's not having a parallel port anymore. Even so I probably wouldn't buy new PC for the CNC table anyway. I'd look for a Pentium 4 class or equivalent AMD with 1.6-1.8 GHz processor with XP Pro & a CD or DVD drive. Most anything of that vintage will have a parallel port.

A refurbished PC of that basic design can be picked up for less than $100.00

[millman52]

I picked up a gateway, that has a pentium 4 1.8ghz. Upgraded the ram to a gig and it has 40 gig hard drive. It runs windows xp REALLY FAST. I picked it up on craigslist for 50 bucks, and bought the ram at a local pc shop out of a bucket of used ram (cause its so old) for 5 bucks!

Works like a charm!

That's about the same thing I am running. I may only have 512 ram. just don't remember. & that's plenty. I also have my Mach kernel speed bumped to 35000 & it runs great.

Mach & most other software used to operate home CNC was originally designed to run on Windows XP or 2000. I'd hate to tempt fate with Win 7. I tried Vista when I first started & Vista was in it's infancy. I'll not say it will not work but I sure had issues trying to make it work.

I bought a new PC with Vista because everything else was new. I gave the new PC to my daughter & bought the boneyard Gateway for $85.00 best I remember I have never regretted that decision either.

[Squickmon]

http://www.hobbycnc.com/products/hob...oard-packages/

There is a FULL kit. At the bottom select 4 axis and 4 305Oz steppers and your good to go (even if you don't use 4 axis's now it will leave your options open). you will have to buy a transformer from the link provided, as well as a case separately. I purchased the kit and it worked wonderful, along with GREAT email tech support and a forum full of help.


Above is the video of the 4axis kit and board using mach.

You have to solder the board together, and assembly is required. good thing the directions are REALLY good.

That got me going from nothing to a fairly good understanding of the whole process. Without that kit i would be 100% lost haha.

i checked out those kits the other night, i was wondering if they came with the stepper motors and if so are they good quality. i've been searching the web and i keep coming across the NEMA stepper motors, are the NEMA motors better? i find packages of motors on ebay for really cheap but i feel like 'cheap' is not necessarily the way to go, kinda feel like im buying junk if i get them. i will be searching craigslist for a windows xp tower. what is a good software to fun, everyone i seem to talk to is running mach 3, a friend of mine told me that any 2D cad will work. any suggestions?