[janmclare]

Hi Guys,

New to the forum, some great designs on here. Thinking about building a homemade CNC router and looking for a bit of advice.

I'm in the UK so not really sure if a lot of the stuff available to those in the US has a equivilant here.

The plan is to build a CNC router 3' x 3'. It needs to be strong enought to mill aluminium. Speed is not that much of a concern but accuracy is (I'd be happy with 0.01"). Not going to use it all that much. I want to build telescope components for my other hobby, astroimaging. Thickest peice of aluminimum i'd want to machine would be around 1/2".

Looking at the web, youtube vids and other home made builds i came upon this design...

http://www.onel.se/all_files/images.html

It looks pretty simple, looking at the rails i would probably double up at the sides. Whats the concencous on this design? The aluminium blocks for this i could get made up by a machine shop.

Motors...

Can somebody spec me a decent set from the site below? i was thinking of a Geckodrive G540 so would prefer a decent set of motors for this controller. Around £70 max would be my budget for each motor.

UK FARNELLONE SANYO DENKI STEPPER MOTORS


I already have BOSCH GMF 1400 CE router so was thiking of using that on the machine itself.

Software i was thinking of using would be Mach3.

Not sure if i've left anything out but please feel free to add your thoughts.


thanks,

Jan

[ger21]

Unsupported rails are bad, especially if you want to cut aluminum

[Crevice Reamer]

Hi. Welcome to the Zone!

I don't see ANY decent motors for G540 on that site.

Keling has reasonable international shipping. Why not email Keling for shipping cost to UK?

These are my suggested electronics:


http://crevicereamer.com/Page__57.html
CR.

[Crevice Reamer]

Fixed the link.

CR.

[janmclare]

Hi Guys,

Would a sliding guide rail system attached to the base to support the sliding blocks be sufficient.

CR. yes buying from Keling is possible, I would have to order the G540 from the US so i could order the motors. Looking at that site i could probably buy a ready made contoller box containing the G540 and a suitable powersupply for 230v.

Any steppers that would suit my needs and budget on the kelling you could recommend?

thanks,

Jan

[Crevice Reamer]

On Stepper motor page. They ARE available for immediate delivery:

KL23H2100-35-4B (1/4” Dual shaft with a flat) 381 oz-in
Specification Price: $49 in Production (2.8 mH)
Can be used for G540, G251, G250 or any other driver

Did you see the entire list?:

http://crevicereamer.com/Page__57.html

CR.

[Crevice Reamer]

Jan: Unless you are going to be running FOUR 3.5A motors, (In which case this $107 10A PSU is what you need: http://www.antekinc.com/details.php?p=209) you won't need that expensive 12.5V PSU. The $60 7.3A one will do you fine.

Check out the $75 ABS G540 box at Camtronics:

http://s120220635.onlinehome.us/stepper-components.asp

CR.

[janmclare]

Thanks for that appreciate it

Would the sliding guiderail attached to the base and the sliding blocks be enough support.

I guess if its not i could use the first machine to machine parts for a more complicated design?


Jan

BTW nice site you've got there. I'm going to read through it tomorrow as i've been looking for a single source, reading bits here and there makes it difficult for a newbie.

[audioandy1762]

Hi Jan

For a UK supplier take a look at zapp automation I think you might find all you need here.

I have no interest in the above company just a happy customer.

Andy

[janmclare]

Andy thanks for that link, i might get my ballscrews from there and possibly the linear motion rails. Other stuff is a little bit more expensive then i can ship in from the US and i prefer to use the Gheko controllers.

I have been looking at the 80/20 frames and have found a supplier in the UK that does similar products so i might build a aluminium framed version. It would simplify what i have to get machined from a shop and would work out cheaper?

Headache if i go this route would be me having to cut the peices to lenght should i need to. Not sure i could get them absolutley square... hmmmm

http://www.aluminium-profile.co.uk/

Jan

[audioandy1762]

Hi Jan

When going down the aluminium profile route just be aware that a lot of the profiles are only very lightweight (like the ones in the link you have posted) and you say you would like to mill aluminium just be careful before you part with your hard earned cash a lot of the light weight stuff is designed for display racking etc.

Another UK supplier is Machine Building Systems who supply the Item range, just have a look and you will see the difference in the different profiles (we use this system at work and I have used it in my build).

Andy

[janmclare]

Thanks for that Andy, appreciate the feedback. I'll have a look around their site and see whats available.

I'll start to do a bit of 3d modeling in the next few weeks to see what designs i can come up with and post them here for critique.

Had a quick look, what profile would you recommend for the build.
They have options 5,6,8 and 12. thanks,


Jan

[ger21]

Hi Guys,

Would a sliding guide rail system attached to the base to support the sliding blocks be sufficient.

It would probably be more complicated and not work as well as proper supported rails. You'd need to support it from moving in all directions. Any flex at all will result in disappointing performance, especially when cutting aluminum. You want something like this.
http://www.vxb.com/Merchant2/merchan...rMotionSystems

Or, more expensive THK type linear rails and blocks.

[janmclare]

Ok guys,

I'm going to get kit slowly and once i've gotten that work on the design.

firstly i'm going to order the following package from kelling.

The 4th motor would be used for a 4th axis at some point.

Kelling package...

"G540 4 axis package (One G540 + Four
KL23H284-35-4B (1/4” Dual shaft with a flat) 387 oz-in + one KL-600-
48 48V/12.5A 115V /230Vpower supply): $624.95"


Now just have to find some good quality linear rails and ballscrews. Once i get these i've got some basic specs from which to make a 3D mockup.


Jan

[Crevice Reamer]

Ok guys,

I'm going to get kit slowly and once i've gotten that work on the design.

firstly i'm going to order the following package from kelling.

The 4th motor would be used for a 4th axis at some point.

Kelling package...

"G540 4 axis package (One G540 + Four
KL23H284-35-4B (1/4” Dual shaft with a flat) 387 oz-in + one KL-600-
48 48V/12.5A 115V /230Vpower supply): $624.95"


Now just have to find some good quality linear rails and ballscrews. Once i get these i've got some basic specs from which to make a 3D mockup.
Jan

The Keling "kits" are same price for individual parts. For best performance, get the KL23H2100-35-4B 381 motors--They are better with the G540:

http://kelinginc.net/NEMA23Motor.html

For four 3.5A using a 4th axis, you could just use a 7.3A 48V PSU for $60. You only really need more Amps if you are slaving 2 motors on one axis.

If you MUST have more Amps, you don't need 12.5, 10A is the MAX you would need and this PSU will save you some money:

http://www.antekinc.com/details.php?p=209

His motors are not optimum, and cost a lot more, because you have to buy $16 extension, but he has good linear carriage and lower price on 7.3A PSU:

http://cncrouterparts.com/index.php?cPath=21


CR.

[janmclare]

HI CR,

I made a mistake with this post, i did not read the motor part number you recommended before correctly...

I should have said i wanted to order this kit..

G540 4 axis package (One G540 + Four
KL23H2100-35-4B (1/4” Dual shaft with a flat) 381 oz-in + one KL-
350-48 48V/7.3A 115V /230Vpower supply: $544.95


I prefer to order the powersupply from kelling as i will only have to pay one handling fee to a courior. This can be around $20 for each package.

thanks and sorry for my error.


Jan

[stevespo]

The plan is to build a CNC router 3' x 3'. It needs to be strong enought to mill aluminium. Speed is not that much of a concern but accuracy is (I'd be happy with 0.01"). Not going to use it all that much. I want to build telescope components for my other hobby, astroimaging. Thickest peice of aluminimum i'd want to machine would be around 1/2".

You must have typo'ed your accuracy specs. 0.01" for a CNC router for cutting aluminum seems like you're off by a decimal, especially if accuracy is a concern. You probably want .001" or better, I'm assuming.

Building a CNC router is a great project, but it can be time consuming and very expensive. Nothing you didn't already know. Especially when you start talking about cutting aluminum the requirements change and everything becomes more costly. A high speed router requires higher feedrates and that requires more speed and torque, even with light cuts. Mass and stiffness to deal with vibration and help with cut quality. 3x3' is a pretty big work envelope, so the gantry is going to be heavy. Etc. etc.

I'd put in a lot more work on the mechanical aspects and have all the components nailed down (frame, rails, screws, etc) before I started purchasing motors and drivers. You really want to match them to the machine, or else you'll be swapping them out in no time. I'm saying this from experience, moving toward my 3rd set of motors, 4th set of drivers and 3rd power supply, not to mention 3rd break out board, and (2) routers and a 3 phase spindle.

Luckily, I've been very pleased with the structure and mechanicals on my machine. As always, your mileage may vary. Have fun!

Steve

[janmclare]

Hi,

That initial post was made before I started to research this seriously.

My first machine is going to be a smaller hobby type build. Once i get this right i will then start on the more complicated build... i'm in no rush and this looks the best way to start out.

Not going to expect too much and just learn from this experence, have a bit of fun too

Jan

[janmclare]

Hi guys,

Finally the design is fleshed out. Lots of problems that had to be worked out from my initial plans. Glad i decided to create a 3D model.

The motors, power and controller you already know about.

Decided to go duel ballscrew for the x axis and slave the motors initially. If this does not work out its fairly simple to convert this design to single ballscrew type.

The base plate is going to be steel and the X axis profiles will be aligned and
bolted to this.

I'm using two 25mm linear rails, with two carrages per rail on each axis.

The Y is made up of two aluminium profiles with leadscrew inbetween.

The Z has carriges bolted to the rear plate and rails behind the front plate with leadscrew inbetween.

The ballscrew will be 20mm diameter with a pitch of 5mm for each axis.

The profiles will be 80x80 for the X and 80x40 for the Y. If another supplier gets back to me i was hoping to use 90x90 and 90x45.

I've decided to go chinese 2.2kw spindle with ER20 collet. The VFD would be a ABB ACS350. I will also be using a David Da Costa spindle mount for the Z axis.

Ok on to the renders...

Would appreciate some feedback on the design please.


thanks,

Jan





http://img251.imageshack.us/img251/124/back1.jpg
http://img85.imageshack.us/img85/7298/side1b.jpg

[ger21]

I'm using two 25mm linear rails, with two carrages per rail on each axis.

You can save some money by going with 20mm. Even 15mm will probably give you more than enough strength, but may be harder to work with, because they are so small.