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Topic: CNC Machine

So anyone have a home "desktop" CNC machine or DIY version? What would one expect to pay for a fully assembled low cost version?

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Re: CNC Machine

3D printers are CNC.

I assume you are talking about a CNC router or mill. Maybe even a CNC lath or laser cutter?

https://www.bilbycnc.com.au/DisplayCat. … ubCatID=90

3 (edited by lotw_1 2013-02-24 11:51:00)

Re: CNC Machine

http://store.qu-bd.com/product.php?id_product=45 QU-BD has a 3d printer/cnc in one machine.

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Re: CNC Machine

There are low-end milling CNC machines on eBay for under $500.  If you are doing wood, then lubrication is not a issue, but if you are milling metal, lubrication systems are important and both expensive and messy.

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Re: CNC Machine

lawsy wrote:

3D printers are CNC.

I assume you are talking about a CNC router or mill. Maybe even a CNC lath or laser cutter?

https://www.bilbycnc.com.au/DisplayCat. … ubCatID=90

Yes, similar to that. Thanks guys these are what I was looking for...

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Re: CNC Machine

I was looking into getting a cheap cnc desktop router off ebay for a while now, haven't pulled the trigger yet. They also have some cheap laser cutters that are pretty neat.

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Re: CNC Machine

Also found these if you are in Australia:

http://www.carbatec.com.au/cnc-shark-machines_c21789

They are originally from the US so should be able to source them easily there.

The first ones I linked to (and seemingly all the cheap ones on ebay) need the computer to have a parallel port, which might be difficult to find. The second one has nice software included and only needs a USB connection.

I'm after one that can cut 5-10mm aluminium, which puts a laser out of the question (without going industrial). According to the message boards of the shark CNC, it can do aluminium with the right cutter/speed combo and multiple passes to cut a bit at a time.

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Re: CNC Machine

lotw_1 wrote:

http://store.qu-bd.com/product.php?id_product=45 QU-BD has a 3d printer/cnc in one machine.

I´m number 4 in the beta program for this one, will get back on how it stacks up.

9 (edited by lawsy 2013-03-05 20:18:41)

Re: CNC Machine

So I have spent a lot of time looking into this and it seems there are a lot of differences between these and out printers, despite being so similar on paper.

Most people buy the chinese cnc routers from ebay, with many upgrading the electronics and stepper motor cabling. Even the Gecko unit of choice seems archaic, running from a parallel port and unable to be run from either a laptop or usb to parallel port adapter. This means you nee an ancient PC dedicated to the machine.

Considering everything 3D printer has onboard electronics with firmware that handles the steppers, this seems terribly inefficient. I did find one system that seems promising:

http://www.planet-cnc.com/

It is an all in one hardware and software solution running from USB. It's closed source and PIC instead of arduino, but apart from this seems very much like how 3D printers are setup. Has anyone got any experience with this?

Another thing I'm struggling with it the spindles. Most have a VFD controller to run them which seems to just convert mains AC and provide a user variable DC for setting the spindle speed. Once again this is the equivalent of our printers handling the X,Y & Z movement and us manually controlling the extruder steps with another piece of hardware. The planet CNC hardware has an add on which I think will handle this. Again, can anyone with experience confirm that my understanding is accurate?

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Re: CNC Machine

Hi Lawsy, You are right about the vfd not working for the extruder drive you will need a 4th axis drive which on a mill is quite nice to have anyway for advanced machining. I have a few cnc machines most of which run off a pport on older machines however I found this ---> http://www.ebay.com/itm/281027063473?ss … 1439.l2649 the other day and will be retrofitting one of my machines to see if it will work on a newer(faster) machine smile since it uses a usb port and says it works with mach3 I should be good to go once it arrives smile... well barring any slightly different electrical signals or timing issues anyway.

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Re: CNC Machine

The 4th axis is usually for a lathe like attachment from what I've seen.

My understanding of spindle control is that the simplest ones are like a trimmer router and have a simple on/off switch on them and maybe a dial for speed.

The fancier ones take a voltage from 0-10V and this determines the speed. The VFD is just a glorified box to convert mains AC power and regulate a smooth 0-10V.

The one I linked to (which is very similar to the one you linked to) has an output expansion board with relays built in switching items like coolant pumps. It also has a 0-10V output for spindle control. With this system it seems like I could use g-code to switch on the spindle and set the rpm, compared to the cheap Chinese electronics where I would have to setup and program the VFD manually to run the spindle.

I've read a lot of opinions about air vs water cooled spindles, do you have an opinion on this? I need to be able to cut aluminium shapes from plate, even if it takes a long time with several passes to reach the entire depth.

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Re: CNC Machine

I have used the 4th axis on mills usually you have the work mounted in the 4th axis/A so it can rotate.

Correct about the spindle control usually just a relay on/off I have a cnc router like this but also have variable control on it(manual). With extra outputs on some of these boards you could rig up a pseudo speed control to give yourself a few different speeds based on the 'bits'(outputs) you have on or off... but for the stuff I do I typically set the speed and run the program so to me it would just be a convenience thing and not really necessary right now.

I hadn't clicked on your link until just now... I thought you were linking to a complete cnc system, but I see it is very similar to the ebay board I linked to... I will have to look at that a little closer as quality is always worth a bit more smile

As for water cooled spindles I would like to get one on one of my smaller machines but I just haven't had enough $$$ to go for a good one yet as I have heard the china ones are prone to problems but from what I have heard water cooled is the way to go if you want nice clean compact and quiet! power smile for now I guess I will just have to be happy with air cooled routers and oversized dremels...

You can cut aluminum plate just fine with or without a VFD/WC spindle, just have to match your depth and feed to the spindle your using so if you go with a fixed speed router that means putting a smaller cutter on it or put a speed control in front of the router but you lose torque and then you have to slow your feedrate down... So basically it comes down to time vs. money... and I am short of both wink

So how thick of aluminum plate are you talking about here?

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Re: CNC Machine

thanks very much for sharing your experiences, it's really helpful. The best thing about the one I linked to is the software. It's like Repetier-Host in that it's a one stop shop: slicing, positioning, hosting and g-code preview. Free download but 70 euros for a proper license.

5mm at a minimum, maybe some at 10mm.

I have a product that I've prototyped by laser cutting from 5/10mm aluminium, but it cost ~$700 and the thickness of the aluminium was difficult for the laser to cut neatly.

I figure if can get make the pieces myself, even if it takes a day of slow machining, I can make the product profitable. It's a week+ turn around from a manufacturer anyway and they charge like wounded bulls for small volume production.

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Re: CNC Machine

Would love to have a CNC as well, Like the USB version compared to old printer port. Thanks for the links.

SD2, Glass Bed, Fan on control board, Simplify 3D, Workbench(on order).

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Re: CNC Machine

Brad wrote:

eBay has some cheap laser cutters that are pretty neat.

Really?  Last time I looked, the best kit I could find was $1000, and the low end fully assembled units started at $2000.

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Re: CNC Machine

jon_bondy wrote:
Brad wrote:

eBay has some cheap laser cutters that are pretty neat.

Really?  Last time I looked, the best kit I could find was $1000, and the low end fully assembled units started at $2000.

anymore I think 4 grand is cheap for a 24x15 inch 35 watt co2 job fully assembled and delivered. especially when I think back on trying to build one about 8 years ago... heck I would've had way more then that in the laser tube itself.

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Re: CNC Machine

Heres an example of a small cheap laser machine: http://www.ebay.ca/itm/HIGH-PRECISE-CO2 … 1060990091

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Re: CNC Machine

Smaller than I would want... but certainly usable for a lot of smaller items smile and for less than a grand delivered smile isn't technology wonderful.

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Re: CNC Machine

Hey Lawsy, I got the ebay board in today, so hopefully in the next few days or over the weekend I can get one of the machines ripped apart and start in on the retrofit smile it will be going in an old 24"X12"X6" isel cnc mill.

btw. it looks like it is just a KO of the link you put up.

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Re: CNC Machine

Looking forward to seeing your results. What drivers are you running for the steppers?

The ones on the planet-cnc website are 2.5A but the power suplly they sell is only rated for 4.5A. Doesn't seem right to me.

Also, after seeing some home made CNC routers easily cutting aluminium with decent woodworking variable speed routers, I'll probably head down that path for the spindle.

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Re: CNC Machine

Well I made some progress today digging into the little mill, I got the main control/driver board out.
http://i.imgur.com/jFTjCsk.jpg
and think I may try to use the driver section of it since it uses L297 and L298 chips as the drivers and it's already put together smile The deciding factor will be how much time I can devote to hacking this to the ebay board and what else I may have to add to it to accomplish that.... and if that doesn't work I have some linistepper drivers but then I would have to either change the mill's power supply from 40V to 35V or just use a different supply... or maybe I'll just get some 6064's...??? The worst part is now it's sunny outside and I am in here on the computer, oh well it's only the second sunny day in a month or two.

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Re: CNC Machine

for a home cnc, what i did for the electronics is:

gecko drives, g203V
pmdx 132
pmdx power converter(because you want 80vdc)
allied electronics dot com for a thoroidal 1200va tansformer

with that setup, you are bulletproof for a 4 axis.

other than that, you can also go for a gecko 3axis driver but it does not give you a lot of power.

you can also split the parallel port and hook up directly to the gecko drivers. it works well, its just harder to do the setup.

your biggest problem is the size of your milling.
am running nema34 850oz/in for x and y
nema42 for z i think its a 1900 oz/in
and that is a small milling.


coupliing have to be bulltproof with absolutly no backlash

ballscrews from china are good enough, kellinginc.net

you need a parallel port to run all that. a 50$ desktop is what i am using.

then the decision:
linux
windows.

on linux you have emc2
on wndows you have mach3

i am usingmach3.

softwares i am running are:
vectric cut3d
mach3
punch via-cad

doing a lot of hand written g-code(you have t learn the g-codes, its not hard)

enjoy.


once you have that, you will soon realise that your milling is too small and you get vibration.

my next one will have a 40'' bed so i can get rid of the lathe and just use a 4 axis milling setup.

if i sell mine today for 4k it will cover the cost of the setup, not the hours i putted on it doing it.



machining require more than just software programation and 3d desing, altough its the hardest part of it. if you're mechanicly inclined you should figure it out pretty esilly. thanks google.

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Re: CNC Machine

those cheap chinese 40w laser are crap.
I just checked one out firsthand.

Slow, inaccurate, and way too small.

fslaser[dot]com looks like they have some good stuff, I'll probably be going for their deluxe hobby model, $2400 for 12" x 20"

I saw them at maker faire (i think). pretty nice.

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Re: CNC Machine

*Blows dust off thread*

Earlier in the year I setup a 3040 CNC router for work and I've been super impressed by it. The ingredients:

- Cheap ~$1500 delivered from aus in two days!) 3040 router.
- Planet-cnc mark2/4 electronics and software
- Meshcam software to generate gcode.
- High quality collet set and cutters.

Whole machine probably cost sub AU$2500 and it works really nicely. Each stepper driver needed four wires cut and placed into screw terminals on the planet-cnc board, with the correct steps per mm entered into the settings. That was it.

I've experienced none of the issues I read about online during my research, like dodgy stepper wiring. Everything has been perfect.

I have to correct myself on a few things above that I previously stated:

- Planet-cnc software only does basic gcode generation, nothing like repetier-host. It is really easy to use and run the machine with, however.
- VFD doesn't produce 10V DC to run the spindle. The spindles are actually three phase and the VFD converts from single phase AC, to DC, then emulates three phase with PWM or similar. The 0-10V DC is an external input so controller boards can control spindle speed by themselves, otherwise there is a dial on the VFD.


Anyway, the time has come for me to purchase one for myself. I'm after a 6040 size, and had planned to go down the same path, but I've noticed the newest Chinese routers have direct usb control through Mach3:

http://www.carving-cnc.com/x61500series … chine.html

Mach3 USB Motion Card
Fully support all Mach3 versions. Maximum step-pulse frequency is 200KHz, No need to install any USB drivers to computer.
10 high-speed optocouplers with 10MHz, 24 general.
optocouplers isolating all of the input/ output signals, this high-cost design provide high performance and stable system.

Can anyone comment on how well the direct Mach3 control works?

25 (edited by iowajames 2013-11-16 15:36:13)

Re: CNC Machine

jon_bondy wrote:

There are low-end milling CNC machines on eBay for under $500.  If you are doing wood, then lubrication is not a issue, but if you are milling metal, lubrication systems are important and both expensive and messy.

Not true, I had a CNC 3020 and it milled aluminum easily, mild steel, well, really really slowly.

It was $575 shipped and worked fine, except the person that assembled it wired the controller wrong. The spindle was running backwards (which is why it wouldn't mill anything initially) and the X axis was backwards & Y was crossed with Z.

Once I figured out the wiring issues, it was a solid little machine. I sold it with the slave computer I put together for it for $700 shipped.

Here is a similar machine:

http://www.ebay.com/itm/NEW-3020-DESKTO … 2a1a9a24ee

If you want one, this one is best offer. You could offer them $500 & they will ask $525. That's how I got mine so low. It is worth it IMHO. Just be prepared to work out a few easy bugs.

Edit: Oh & while milling soft metals, just stand by with some cutting oil in a spray can to lube the mill occasionally. Not messy at all.

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