CNC Router with DC Spindle

[rodm]

Well I am at it again and have nearly finished my third CNC machine. This is a little one with a cutting envelope of X 300, Y 200 and Z 90mm.

I have fitted a custom spindle that has three bearings and a 1/8th inch collet. I have matched a DC brushless motor and variable speed controller to the spindle. The idea is to get a very quiet machine and still have plenty of power to do some serious cutting. The motor/spinlde will rev to 35,000 RPM and don't be fooled by the size as it has plenty of grunt to drive the cutter full bore into a piece of hardwood. I am using a salvaged 380 watt computer power supply for 12 VDC.

The machine has been consructed using actuators and wrapping a bit of aluminum around them to keep it all in place. It will have a 10mm aluminum plate for the table top so it should be quite rigid and hopefully be light enough to be portable as well.

[Harry72]

Does this one have a pacific purpose?

[rodm]

Not really as it can be used for any machining of wood, plastics and aluminum that fit within the cutting envelope. I expect accuracy of one to two thou as it has ground ballscrews.

It has the advantage of being portable and quiet so I am hoping to move it inside and trial new designs. A hood would be fitted if I do this but I haven't asked for approval to do this yet. ;)

[marker]

Rod
What is the brushless motor you are using, is it 36mm dia x 76mm long like these. http://www.fastelectrics.com/brushlessmotors.asp

What is the speed controller you are using and what are they worth ?
Mark

[rodm]

Hi Mark

It is a Walkera 380 Brushless with a Tower Pro 70A ESC and purchased from Hong Kong through Ebay - watch the freight

Amongst others we have an electronics engineer in our CNC group who made and programmed the controller to make it variable speed. All jiggery pokery stuff to me. :D

[sea dragon]

Am I unique or not?
I read all this thread, hoping to learn something.
I have finished the reading and now, would be happy to say I understood something.
Okay, I knew "router", but after that?

[gazaly]

Does this one have a pacific purpose?
I don't think it would work in any ocean Harry :D

(Sorry mate, it was too tempting)

[Vasco]

Rod,
now that you have had plenty of experience and you seem to be in the mood, could you build me one:D

Regards
Vasco

[rodm]

Hi Vasco,
Good so see you are still around and interested in woodwork.

Sea Dragon,
CNC stands for computer numeric control so these machines are operated through a computer. Do a search on this forum and you will see my first two builds and a video showing one moving about. CNC equipment is not new and is in most major cabinet shops now. Entry cost is high for this equipment so fortunately there is still a place for hand made wood products.
To give you an idea of cost that little machine in this post will cost me about $1,500 to finish and all of the components with the exception of the spindle (small router) and the aluminum are second hand.

[Mick C.]

Rod, Just curious about the $1500 u mentioned. I take it that most of that got gobbled up by the ball screws and stepper motor drivers and interface???? or have u reused them form previous CNC's????? Am asking from a point of view of makeing one myself and seeing that a ballscrew and rail setup would be soo much easier and more accurate than making it all from scratch.

[rodm]

Mick

All of my three machines are independant and do not share anything including the computer so the $1,500 is for a stand alone machine.

Having built skate bearing rails on my first machine i do not recommend it. There is a lot of effort required and they are still not as good as linear rails.
The actuators I have used on this machine have a ground ballscrew and four linear rails built into each unit. They are very strong and provide excellent rolling motion as well as strong radial loads.

I got all three actuators for about $500 Australian landed. Sounds expensive but you get ballscrew and linear rails in the one unit for this price.
3 axis Driver Board and power supply made local by electronics engineer $190
Aluminum - $200
3 x Motors - 276oz Nema 23 - $172 Australian
Computer - $150
Spindle - $300 including motor and electronics.
Total $1,512
A few cap screws, wiring and hardware items thrown in will add another $100 to this price.

Ebay is you avenue to getting these bits and you will likely have to purchase overseas.

It is expensive but you get used to it. I justify it because I get the equivalent of a table saw, bandsaw, router table and engraver and more in one machine and to a far greater accuracy than I can do by manual methods. Sounds like I need to chuck in a set of carving knifes. :D

[rodm]

The mechanicals are finished so I have added another photo which might make it easier to see how this works.
I have fitted a 10mm aluminum plate for the table top and knurled knobs to the motors. I also tidied up the odd bit here and there and mounted the spindle switch box.

I have also included a photo of the driver board and power supply. An engineeer here in Perth makes these and they have proven to be rock solid. Full opto isolation as well as 5, 12 and 24 volt outlets and heaps of great features. The electronics is all a bit mumbo jumbo to me so excuse me glossing over the details. The front and rear panels were cut on my first machine - Obott.

[b1ueshift]

Very interesting machine. I'm considering building one myself. Just trying to think of enough useful projects to justify the investment.

What do you make with your machines?

[rodm]

These machines are very versatile and I have done a wide variety of work.

Engravings, Carvings, cutting out shapes, pockets, inlays, drilling hole patterns in materials such as wood and wood composites, plastics, aluminium and brass.

I work mostly in timber but I have done a bit of work for a local car club on custom dash inserts and grill features. I have also done a lot of aluminium plate work making parts for other CNC machine builders.

The work just rolls in by word of mouth once you have a machine running and can produce a reasonable quality product.

To give you an example a fellow forum member who finished his machine two weeks ago already has orders for 26 items. He is still learning to use the machine and the software so this is a good indication of the ease in producing quality products as well as the potential market for CNC machined goods.

[rodm]

I gave it it's first run today and was very pleased with the little spindle.
I'll let the video show it all.
http://users.tpg.com.au/leerod/jabott_001.wmv

[b1ueshift]

Neat little machine Rod.

Could you, or someone who knows about these machines take a look at this link and tell me if you think it's a good buy? I'm considering bidding on it, or buying/building something like it.

http://cgi.ebay.com.au/3-Axis-CNC-Desktop-Hobby-Router-Home-made_W0QQitemZ200033909264QQihZ010QQcategoryZ105827QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[rodm]

Sorry but I would not recommend a home made machine without close ups. There are too many important components that need to be in alignment and of at least a certain quality before you have a good machine.
A couple of points on this machine is I would like to see the gantry sides a bit stronger and 0.3mm is not high accuracy for a CNC machine.
Best I can do.

[b1ueshift]

Thanks for the info. It's hard to find good info on small cnc machines - a lot of sites want to sell you plans so don't want to give much away.

[rodm]

Hi b1ueshift

There is more information than anyone can absorb on the CNCZone forum.
www.CNCZone.com

I don't like taking people away from the Ubeaut Forum but there is not the interest on this forum yet to be able to gather enough information.
I keep trying to raise an interest here and that is why I start a CNC thread every now and again.

I have three detailed machine builds on CNCZone and five other Ubeaut forum members have machine builds on there as well so it is slowly gaining popularity. There are quite a few Australians on their Forum and they have set up an Austalian Clubhouse so you should feel at home.

On your first machine there is a lot to learn but it is not difficult. Go have a read of all the machine builds and I am sure you would be able to design your own. There are some free plans on there so look out for those. Jgro is a popular design and it is made from MDF. I spent many months reading threads before I made my first machine so be prepared to invest a lot of time gaining the knowledge.

If you want to send me a PM some time I am happy to discuss any details you might want.

[Ladislav]

Hi Rod,

can you please explain what is "Tower Pro 70A ESC"? Also I would like to know, that spindle, did you make it your self, did you buy it, or is someone making them at request? What software are you using to drive the router, and which operating system are you using? DOS interfaces easily to the outside world, but is getting a bit outdated. If you are using Windows, how do you interface the machine? I hope you don't mind answering all this questions. I started building router my self, the mechanics were not so bad, but I boged down at the choice of spindle, and the software. Mybe I may be able to finish it if I will get some advice. Thanks Ladislav

[Ladislav]

Ooo, and one more thing Rod, the X, Y and Z motors are they stepper motors, or DC servomotors. I used Baldor servomotors on X and Y, and a stepper motor from an old printer to drive the Z axis. Test runs using DOS computer and Baldor test program looked quite good. After I solve the problem with the spindle, and decide which software to use, I guess I will have a working CNC router too.

Bye Ladislav

[rodm]

Hi Ladislav
The Tower Pro thingo is the motor controller for a bruchless motor. This sort of electronics is a bit technical for me and a local electronics engineer put it all together for me. The spindle was purchased from USA on ebay.

Just to let you know the spindle was a failure as it didn't reduce noise much because as soon as you start cutting the noise is almost as bad as a small router. I am taking it off and putting on a variable speed 6mm collet die grinder. If you want something small maybe a Dremil?

I use Wondows XP and Mach3 software. The interface is throught the serial port (printer port) of the computer.

If you want to stay with Dos then TurboCNC is free and it is a very good and well proven software. It uses the serial port as well.

All my machines have Nema 23 stepper motors and Bi-polar driver boards that operate on step and direction commands.

Your machine sounds intereting and I would like to see some pictures of it.

[Esmae]

Hi Rod,
Good to see that you are sharing so much. Your keen interest has been inspiring me. I have been researching on and off the last few months the possibilties of building my own table too. working areas X-1250 Y-650 Z-200. I'm still in drafting stage at the moment but i have been researching costs so i thought i'd list a few (Australian and international) suppliers to save everyone doing the runaround (remember eBay is your friend).
Blackwoods AU - Acme lead screw 5/8 3mt Approx $150
Nuts $16ea (not anti-backlash. still waiting for quote, definitly available international anyway)
Steelmark AU - Precision Ground Hardened steel rod 38.1mm 6mt $135 (not sure if this is right hardness yet M1030)
eBay VXB Bearings - Linear Bushings/Bearings Best price i could find (eg $10au per bearing compared to Local australian average price of $160 :eek:.
Local Aluminium Supplier _ Aluminium extrusions are as cheap as chips. Pay a bit more and you can get stuff that just bolts together.
Local electronics - Limit switches etc.
Xylotex USA - Almost entire electrical componentry

That covers the hard parts anyway. Anymore suggestions Rod or anyone else? It'd be nice to keep all the buying in australia but some of the prices here are truly ridiculous.

I'd love to get Ballscrews but the budget cant quite take it.

[rodm]

Thanks for your post Esmae

The acme thread is very expensive in Australia and those nuts are just normal hex nuts with an Acme thread for $16.00 each. You can buy all this ex USA, pay air freight and save heaps on the Australian prices.

I can't get over the prices Australian business charge and either they are very inefficient, there are too many bleeders sucking off business or they want to retire early so I will not support them when their pricing is outrageous. They must think they have a captive market but with the internet they need to wake up. Rant over. :D

Try here for Delrin anti-backlash nuts.
http://www.dumpstercnc.com/

Try here for reasonably priced ballscrews and stepper motors.
http://www.homeshopcnc.com/

Xyolotex is a good product and very good support. I have two of his boards and power supplies.
http://www.xylotex.com
If you are keen and can put together a PCB then Hobby CNC or locally the Oatley boards are worth a look.

Try here for stepper Motors - ex factory in China and will supply to individuals. ($18.00 US each for 276 oz Nema 23)
http://www.ms-motor.com/HB1.htm

I also use VXB for bearings
http://www.vxb.com
I had twenty metric angular and deep groove bearings delivered in 5 days for freight charge of $11.00 US and saved about $300 on the bearing compared to sourcing them in Australia. This is a good example of what I was saying above about Australian Suppliers.
I use standard micro switches for limit switches and source them from Dick Smiths.

Aluminum is expensive when you use 10mm plate like I do as it sells for $12.00 to $16.00 a kg. Worth ringing around.

There is probably a few I have missed so if you need anything specific get in touch.