Ok, few questions before I start

[Buick455]

i have been lurkin for a long long time here and it seems like every time I think ill be able to start, something jumps out and bites me in the wallet, lol.. i would like to build a medium machine to start off then build a bigger one later.. in my eyes is a range of 18x14x5 would be perfect for the small projects I do, and it would fit on my desk.. 1/8 alum would prolly be the hardest materal i need to cut parts from or engrave. I have a few dremels & routers lying around so i might be covered there.. oh and I have plenty of PC's around..


my questions are:
1. can a 18x14x5 machine, capable of cutting alum really be built for $500?
(including the motors & controller)

2. what design should i go with?

3. where should i start? motors & controller? frame?

4. what motor & controller setup should i go with if i plan on building a bigger machine down the road? like 48x48

thanx in advance
Bill

[nicanor76]

IMO a typical decent 1st DIY table would cost at least $1k for everything, give or take. You could get away with cheaper but may sacrifice on accuracy or something else. Most of the budget would go towards bearings/slides and control board/motor setups.

IMO spend good $$ on the best bearings/slides you can afford and skip DIY skatebearing setup. I heard that alot when building my 1st, but still used skate bearings because of budget and not satisfied with results. But also good experience to build your own bearings so you know why good bearings are worth it.

[grahamshere]

Like nicanor76 if you get good bearings/slide your better off but you can get away with skate bearing, get apec 7 if you can or apec5 , you can get cheap drives and motors for under $400 xylotex has good drivers. you'll probably be build out of wood if your budget is limited. which is ok for a first machine.to cut aluminum you,ll need a router with 8000 rev's and some horse power. Graham.

[Buick455]

any second hand junk that i should look for that will have bearings or slides for pilfering? maybe even motors..

[nicanor76]

ebay will save you if you know what to look for. Search bearings and read a bunch of past threads to get an idea what to look for, etc. But in general you'll need (at least) 12 bearings and 6 slides so will add up even if you find them half price, but well worth it if you want a machine with minimal play (= better accuracy)

[ahren]

Buick,

If you're interested, I sell a line of low cost components for CNC routers. They're a professional take on the skate bearing option, and are designed to work with aluminum extrusion and cold rolled steel. For a smaller machine, you wouldn't need much in the way of extrusion (which you can get surplus from 8020's ebay store), so you could keep costs down considerably. $500 could still be a stretch, but definitely under $1000.

Whether or not you use my parts, I would start with the mechanical assembly first, and then move to the electronics. Getting a mechanism rolling seems to be inspiring to a lot of people on the zone (myself included) to help them finish the project. Of course, I'm a mechanical engineer, so take that with a grain of salt .

Good luck!

Ahren
www.cncrouterparts.com

[TOTALLYRC]

Originally Posted by Buick455 i have been lurkin for a long long time here and it seems like every time I think ill be able to start, something jumps out and bites me in the wallet, lol.. i would like to build a medium machine to start off then build a bigger one later.. in my eyes is a range of 18x14x5 would be perfect for the small projects I do, and it would fit on my desk.. 1/8 alum would prolly be the hardest materal i need to cut parts from or engrave. I have a few dremels & routers lying around so i might be covered there.. oh and I have plenty of PC's around.. my questions are: 1. can a 18x14x5 machine, capable of cutting alum really be built for $500? (including the motors & controller) 2. what design should i go with? 3. where should i start? motors & controller? frame? 4. what motor & controller setup should i go with if i plan on building a bigger machine down the road? like 48x48 thanx in advance Bill

Hi Buick455, Lurking is cured by doing and I have been cured.
1. No, unless you find great stuff for free. (Just my opinion)
2. No Idea
3&4 See below

If you already have the computer(s). Try a couple of different software packages and see how you like the general feel. I personally use Mach 3 because I chose to have only one program in my shop (I still have 2 but that is another story). I looked a EMC/EMC2 and I have no problems with it but it didn't have the drivers to run the motion control that I went wtih. (DSPMC-IP). I have found that the ability to turn some motors under cnc control will motivate you to build the machine.
I am an "electronics tech" at work.

I found on my first build that when I had the machine done it was a real drag to not have the motors turning. It looked like I was all ready to make stuff and then there was days and days of wiring and tweaking of the drivers.
Just my 2 cents.
Make sure that the first thing you wire is a good e-stop switch(don't ask how I know) and then the limit switches. I still have a small machine without limits and if you run into the end stop it isn't a big deal, but as soon as you have more power it is asking for trouble.

If you plan on $1k you will have a machine that you will really enjoy using. If time is not a big issue you will get much closer to $500. At the low end you will wind up with motors and drivers that will not work on the larger machine in your future.
If you really enjoy this hobby, you will!!!! wind up with a lathe and/or a mill later on. It is pretty easy to set up your control with quick change wiring and setup Mach3 with a lathe, mill, and router profile. This way you only have to buy the electronics once.

Best bang for the buck and the most versatility would be the gecko g540 4axis driver and breakout board all in one which includes an analouge output to drive a motor control(vfd or dc).
$300.
3 nema 23"s should be under $100.I would shoot for 3.5 amps at around 2.5mh inductance. Max amps for the driver being 3.5 will give you the most torque at speed. Keeping the inductance low will mean you will get max speed for the 50v max the driver is capable of. I would worry more about the max amps and the shoot for the closest inductance that you can find. On a machine as small as you are talking about close is more than enough.

50v 6amp power supply under $100.

$500 dollars gets you a great motion control system that will run a large array of machines. It will run a 8" lathe easily, an x2 definatly or x3? mill and your router will fly.
This would run your Proposed 48 x 48 router if you have the 50v power supply and run a 2 motor system on the Xaxis. The x normally is the largest and heavest as it moves the y and z along with it in the typical bridge setup.
I use 2 rotozips at once (cuts 2 parts at once) and they get the job done but an upgrade is in the works.
A dremel will work if you keep within it limits and of course a router will work great for many things.

You could of course go with a Xylotex system (http://www.xylotex.com/Econo3AxSpecial.htm) for less money but the speeds will be lower and you will still need a breakout board and won't have the vfd ouput option.

Ebay for three sets of slides and even use wood for the structural components and you have a machine. Don't forget screws or rack and pinion to drive it.

My 42 x 42 has a wood table as the foundation and it works well. I don't do aluminum on it but for fiberglass and cf or wood it works fine.
It is all about how accurate you need it to be. I do a lot of work for a customer that replaces his drill press and bandsaw work so +- 0.010 is way over done, but it makes me look great.

Please ask any other questions you may have. If I had started asking questions sooner I would have saved a lot of time and money.

End of Ramble.
Mike

[Buick455]

Total - Do you have build log of your machine? i cant find it here if ya do

Ahren - damn dude I like, I like!! The idea of just gettin parts and bolting it all together makes me very happy as most of the parts confused me.. Whats the bigest resonable size you think i can shoot for if i go with your design with a $1500.. ($500 was a lil silly of me) but i might be able to swing 1500 over the long term.. i will be building for 3 years but it will keep me out of the wifes hair =)

[dertsap]

if you go with v-bearings and run them on angle iron or square tubing you'll have a dead solid and economical slide system if you do it right , i used both angle and tubing on mine and i wouldn t change anything i did on it
steel square tubing is cheap and you can buy a little buzzbox stick welder for about $100, so you'd be able to zap together a frame and gantry for a half decent price ,and if your resourcefull you can build a pretty decent system for about $1000 or even a little under , generally the drivers and motors are the bulk of the expense on these things , the machine itself is quite cheap to build especially if your using diy methods for slides .
also watch ebay it's surprising the deals that can be had if a guy is patient and paying attention , for eg i got a set of 3 slosyn drivers for my kids machine for 30 bucks , they work awsome also i scooped up 4 400 oz motors for it somewhere around $60 ,, the deals are at most times slim to none but sometimes the right thing does come aong

[TOTALLYRC]

Originally Posted by Buick455 Total - Do you have build log of your machine? i cant find it here if ya do Ahren - damn dude I like, I like!! The idea of just gettin parts and bolting it all together makes me very happy as most of the parts confused me.. Whats the bigest resonable size you think i can shoot for if i go with your design with a $1500.. ($500 was a lil silly of me) but i might be able to swing 1500 over the long term.. i will be building for 3 years but it will keep me out of the wifes hair =)

Not yet. I bought it half done from ebay and I am not sure if I have enough pics to do a build log. (I paid almost 2k with shipping. If I did it now I could do it for at least half.) I will be doing a log of my BTC-1 retrofit with a Dspmc controller soon.

Plus a log of the other 2 or 3 cnc jobs I am working on.

I agree with derstap that you can work wonders with $1k especially if you shop ebay and know what you are looking for. Mine has supported linear bearing for the x riding on 2" shafts. Took awhile to get it to roll with out binding but it works fine.

Mike

[Buick455]

i have started the "no sweat, no blood build" (you know the one in your head & on random napkins). I like this 8020 stuff.. did i say i miss my Erector set =) anyway on paper im up to $750.00 (give or take depending on ebay) and this is w/o the 8020 + hardware, motors + controler & router.. all in all, im not to shocked by the total.. yet =) if all else fails I can sell a kidney, lol.

i have opted to go big'ish or go home. im gonna shoot for just under 36"x36" (them rods look too nice to cut). i have no issues with the 8020, but my motors & controller choices are gettin the best of me.. the electrics are really the only thing stopping me from jumping in the pool.. a kit would be nice, but a parts list and tutorial will do..

thanx again everyone =)

Oh... I almost forgot... any good assortments of bits out there like milling bits for AL and carving wood... Or a post / thread describing the different types?

[Buick455]

hmmm 1 more question mainly for ahren i guess.. if i go with the extremely simple but pricey 8020 should I go with the lite or the heavy versions.. im sure ppl have done it both ways but i wanna know if theres any pitfalls to the lite, or the heavy for that matter