Jack's CNC build

[Jack000]

been researching for a few weeks now, and today I've finally taken the plunge and sank about $100 into parts and materials.

I'm a casual diyer, but this will be the most complex thing I've ever made, so I've decided to follow this site pretty much step-by-step:

http://buildyourcnc.com

here's my workspace/bathroom (same as the author of that website, funnily enough):



I think I'll document my progress and budget on this thread as I go along. (and probably lots of questions too!)

wish me luck!

[Jack000]

spending so far (canadian $):

6' aluminum angle: $23
24"x48"x3/4" MDF: $11
miter box: $11
100 5/16" screws/nuts: $15
wood boring bit: $7
tap + handle + screwdrivers: $25

total + tax: $100

hoping to keep this under $1000. Think it's possible?

[FandZ]

Like the work space. I grab the dinning room floor, back patio, and the occasional bathroom when I'm in need. Basically wherever my children are not when I need to get something done...lol

I'm still in the research and planning phase and the only thing piecewise that I'm finding hard to get a deal on is electronics and the motors. So far I'm thinking that'll put me back between 500 to 750. I've seen some cheap builds out there but I'm looking for above average results. Have you thought about what you are going to go with power wise?

I'll be keeping an eye on your thread, looks like you are off to a good start.

[chazmtu]

I remember building mine, I had no idea what I was doing either, but it was a great learning experience. It's entirely possible to build a nice machine for under $1000, in fact I think I saw one build from all extruded aluminum for that much on hackaday I think.

what are you looking at for motor drivers? I use the hobbycnc driver with decent results 25-30ipm, probably more but my machine starts to vibrate after that. For some cheap reliable power you could try some old pc power supplies. With a little modification they can be hooked up in series.

[Jack000]

haven't thought as far as the controller actually. I'm just going to start building the mechanics first, since I usually find myself endlessly planning and getting nothing done. I'm a decent electrical engineering student, so I might just make my own to save some money.

I was thinking old pc power supplies too actually (my old pc just died so I have one lying around). For the motors, maybe something from xylotex? They're the cheapest I could find, including ebay.

just 1 question for now:
I noticed that there's very little price difference between the 200/300/400 oz.in motors. Why would anyone buy the less powerful one?

[chazmtu]

what do you know, I'm an EE student too. What school? I go to lawrence tech in Michigan. If you want some good performance you'll want to buy a chopper drive as opposed to building your own. xylotex and hobbycnc are good affordable choices thought there are many many more out there, and you'll want a supply close to the maximum allowed voltage for best results.

As for your question, I may be mistaken but I think higher torque motors have a lower maximum speed and you'll want a little freedom of choice to get a nice clean cut in a variety of mat'ls. I use the 305oz/in hobbycnc motors I got with my chopper drive and they do pretty well. At around $50us each my motors were the most expensive part on my machine.

[TOTALLYRC]

Originally Posted by Jack000 haven't thought as far as the controller actually. I'm just going to start building the mechanics first, since I usually find myself endlessly planning and getting nothing done. I'm a decent electrical engineering student, so I might just make my own to save some money. I was thinking old pc power supplies too actually (my old pc just died so I have one lying around). For the motors, maybe something from xylotex? They're the cheapest I could find, including ebay. just 1 question for now: I noticed that there's very little price difference between the 200/300/400 oz.in motors. Why would anyone buy the less powerful one?

You are falling into the same trap that everyone does when they don't have all the facts.
The motors torque is a holding torque and it falls of as the speed of the motor is increased. The fall off is much greater in the larger motors due to its inductance and other factors.

A small machine like a Taig or similar can use the 282 oz/in to great advantage because of the 20tpi leadscrews. You need a motor that will rev compared to a machine using a 5 tpi leadscrew. And really how much torque do you need if the 282 will snap cutters like butter, what good will something with twice the torque do for you?

Drivers. G540 will run this machine at great speeds with excellent control and resoluiton.
It will also run the next 2 or three better machines unless you get into something that needs real big notors to run.

For the engineers, read the thread from mariss of gecko drives,

Cheap drives?

about how the G540/250/251 came into being. Less than 1 year sfter it hit the forum.

Mike

[Jack000]

the thing is, I'd like to be able to route 1/4" aluminum. Do you think a motor with less holding torque, combined with a higher tpi lead screw will give better results? My machine will be based on a 2'x4' mdf board.

The G540 looks great, but it's a little out of my price range. Maybe the 251 instead, or else I'd have to cut into my food budget : ]

I go to SFU (that's in vancouver, canada). And yes, we live in igloos and say "Eh" all the time.

oh, and I found a great place to buy skate bearings. Apparently they're having a sale. I loaded up on 100 for $30. 'course with shipping that came to $50.. Oh well, after this I can make another router, or three...

spent: $153

[TOTALLYRC]

Originally Posted by Jack000 the thing is, I'd like to be able to route 1/4" aluminum. Do you think a motor with less holding torque, combined with a higher tpi lead screw will give better results? My machine will be based on a 2'x4' mdf board. The G540 looks great, but it's a little out of my price range. Maybe the 251 instead, or else I'd have to cut into my food budget : ] I go to SFU (that's in vancouver, canada). And yes, we live in igloos and say "Eh" all the time. oh, and I found a great place to buy skate bearings. Apparently they're having a sale. I loaded up on 100 for $30. 'course with shipping that came to $50.. Oh well, after this I can make another router, or three... spent: $153

Eating is overated.

With what size cutter? depth of cut? what kind of finish are you looking for?

Cutting alum on an mdf based machine may not be possible due the the forces involved, but somebody will have more knowledge than I.

Gecko is having a customer appreciation sale for the next week or so. Get the drives now and save some coin.

I have 6 of the 251 awaitning installation as time allows.

[gfc62]

Jack,
Last Spring I built the same machine from Patrick's site.



You're going to have lots of fun (and maybe a little frustration at times) but will end up with a very useful tool and will learn an amazing amount along the way.

I don't envy you cutting everything by hand. Do you know anyone with a tablesaw? At the very least have the lumberyard or hardware store cut the MDF into strips with a width that fits tightly into your mitre box.

Since you're an EE student you should check with your department chair to see if you can turn this into a special projects class for credit. That might also help you get access to whatever shop facilities they have.

My advice on the motors / drivers is to buy the best you can. You can always resell them for a reasonable fraction of your investment but likely you'll want to build a 2nd machine using your first to cut parts so you can have greater precision and rigidity. It's nice to be able to reuse your motors. I bought the Keling 425 oz/in motor package for my first build and am reusing them on my current, larger machine. The G540 package from Keling (I think it's $579) is better still but wasn't available when I built my machine. I have friends who used the hobbyCNC pro boards very successfully as well.

Let me know if I can help answer any questions that come up.

Gordon

[Jack000]

yeah, going to get my cousin to cut it into strips first. I do have access to the school shop, but transporting all that mdf would be a pain..

I didn't realize the drives would be so expensive (or that I needed one for each stepper). 3 of the g251 would run me $150, and another $150 for 3 steppers. Has anyone had a good experience using open source drive designs?

just wondering about the g540 - why does it cost $299 if 4xg250 = $200? what are you getting besides the ds9 connectors? probably not going to buy it, but just curious.

[CarveOne]

Because you are paying for a nicely finished aluminum stamping that is silk screened, plus the connectors and hardware, and the labor to assemble it - in addition to the cost of four G251 boards. Many people will buy it this way for the convenience.

You have the option to mount them in your own chassis by ordering just the individual boards.

CarveOne