Looking to buy a CNC / Please help

Hi all,
I am relatively new to DIY CNC machines. I have been looking for one pre-essembled so I can load my PC with software and start learning how to use it all. I want to mill and engrave aluminum as well as carbon fiber sheet, plastics and hard wood. Just as a hobby and to make things for my workshop at home.

I do not want to spend a fortune. I have found one for sale, here in France. Please could you take a look at it and advise me what it might or might not me capable of ?.
I have used Google translate to get the description into English the best I could.


- Course X: 470mm (560mm with less possibility of rigidity)
- Travel Y: 300mm
- Travel Z: 150mm

Engine Transmission Thread: toothed belt on 3 axes

Transmission ballscrew on 3 axes:
- Y: Steinmeyer 20mm (High Quality)
- Z: Trolley mounted on THK rail, screws 16mm (High Quality)
- X: ball screw 16mm (Brand unknown)

runners:
- X and Y: Rails cylindrical hardened steel and chrome plated 25mm
- Z: prismatic Rail

Spindle :
- Proxxon BFW 40 / E control module with 250W
- 900 to 6000 rev / min
- Bearing robust planned for machining aluminum

Electronics:
- Map mechatronics 4 axes ( 1/8 1/4 1/2 and 1) with many inputs and outputs for accessories.

- 4 probotix Motors NEMA 23 400 oz / in
(1 additional engine for a 4th axis)

Milling with sensors limit of Y and Z

Maximum forward speed: 1400mm/min
Accuracy: 0.005 mm

aluminum vacuum table (can be changed)

Comes with:

- Lots of strawberries
- Case control
- Connectors
- 1 Motor NEMA 23 additional
- House of protection

Machine ready
Milling machine operated under Mach3 but can very well with other software.

Hours of Operation:

I give up to 5 hours of operation
The machining was the longest 50 minutes

The total price of the machine parts came easily to 2000 Euros (Borderless or labor).

hi and welcome.

the main limitation with that machine are the unsupported rails and the low power of the spindle motor. its ability to machine aluminium will be severely limited as its not rigid enough to do anything more than very light cuts, think engraving rather than machining. also, while the resolution might be .005mm the accuracy wll be nowhere near that. its good enough for making pcbs or engraving plastic coated aluminium panels or cutting balsa or softwood or plastic parts for model aircraft or doing simple signwork in mdf as examples

Thanks. I was looking at the ebay Chinese 6040 machine, but I read too many bad reviews about them.
I was thinking maybe that I could replace the spindle on the French CNC with a better one and it would still do a better job than the Chinese ones. ?
The other thought I had was to buy a "Merchant dice LTD" machine ( ebay 31037721936 ) and add motors/spindle and a cheap controller . Would this be a better solution ? although more expensive. They have advised me that the max cutting depth per pass in aluminum on this model is 1.5mm. What would the French one do in your opinion ?

Quote:

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Originally Posted by dudz

Hi all,
Comes with:

- Lots of strawberries
- Case control
- Connectors
- 1 Motor NEMA 23 additional
- House of protection
.

---

it's probably worth it for the strawberries! sorry, couldn't help it...looks like Google Translate (which is a godsend) failed on that one .......dudz, strawberries are a fruit :-) so you're saying that the CNC machine comes with a lot of fruit :-)

That machine you've posted photos of looks reasonable to my (non-expert) eyes! I'm not sure I'd pay 2,000 euros (especially since its used)....I have that same spindle & whilst it's a nice quiet, quality spindle, it's rather heavy (so may challenge your Z motor to get fast rapid movement), somewhat underpowered & the 8,000 max rpm will severely limit your cutting speeds

I knew someone would pick up on the strawberries ! .. He is asking 1500 euros delivered from 600 miles away. Inc the controller, and spare motor. I am new to all this. So I would like to know if I can mill aluminum with good results ? (if I change the spindle to a Kress 1050 800w (for example). I don't mind if it takes me longer to mill than it should. I just don't want to buy something I cannot use.

Depends on your definition of good results. With the lack of rigidity the finish could suffer and with that spindle you'll be limited to small cutting tools so removing any significant material is going to take a long time. Its going to need dozens of passes rather than two or three. Its hard to be definitive but I think you'll find it limiting for anything but the smallest of jobs.

Personally if I was buying secondhand I'd want to see it cutting and do some trials first...

Do you think going down the "Merchantdice" route would be better quality/results ??

Quote:

---

Originally Posted by dudz

Do you think going down the "Merchantdice" route would be better quality/results ??

---

I Nievely sought interest within merchantdice's product range. I was overwhelmed by the interest and the potential of diy cnc before considering the pedigree of the machine.

Basically I've come to learn that what they offer, in my opinion, is basic and if you actually intend to cut aluminium with any sucess stay clear of a merchant dice machine.

I'm sure for some applications they work well, I just cant imagine one that would be suitable to my cnc needs.

Probably best to discover the wonders of supported linear rails, and profile rails. Rigidity is key for these machines to be fit for any decent purpose.

Then I think I might go with the French one. I understand it is not the best, and not really suited to aluminum, but its a starting point I think. Maybe I will change the spindle for an 800W Kress if it improves things.
After all; I have seen the Chinese ones from Ebay mill aluminum "out of the box" after a little calibration.

Dudz,

The French machine can be improved upon from where it is at (adding a back plate to the gantry to improve rigidity and when able going over to supported rails (or profile if able) for the Table. A Kress 1050 FME is able to cut Ali' and I get rather good finish with it. It really depends on what you want finish product wise and what are you are willing to accept cutting time wise.

Good luck and keep asking questions even when you don't like the answers take them on board and chew on them a bit. Most the folks here really do want folks to do well.

Michael

Hi Michael,
Thanks, I appreciate that. I was more worried about the size of the workable area more than anything else. I was looking to get 600x300x75, but prices just kept going up and up depending on that.
If I manage to get it, I will play around with it (asking lots of questions on here I expect) then start upgrading where I can. Time doesn't bother me. Finish a bit more.

cheers

That size and the ability to cut aluminum require a good bit of rigidity. If go look at my build here http://www.mycncuk.com/forums/router...d-machine.html and look at what the machine looks like, you see a machine that has a 845 x 345 x 135 cutting area (a bit more really but that is what I use). It is also rigid enough to cut metal. Though only weak spot in it currently is the spindle and a SuperPID or upgraded spindle would deal with that. If you know folks that weld near you, for the money you want to spend you could build or have built a machine that will do what you want.

Michael

Fabrication in France is 3 times the price of the UK.( Nearly 45% of our wages are deducted for health care !)

I might take the chance this weekend and buy the French Machine (as it is user ready).
I know it has 43mm spindle collar. The bloke sais it is up to handling the Kress 800w FME. Would it be possible to use the 1050 FME ? or the Chinese water cooled 1.5kw spindle ? would these give me any large benefits ? then I can change the rails to supported ones when I get used to the software etc....

Changing the rails on the X and Y axes to supported and using a Chinese water cooled spindle would make a huge difference. The Kress 1050 is a very good router, but it's still a router not a proper machine spindle so for instance suffers from a lack of rigidity and higher run-out. If you're getting that machine I'd advise making changing the rails to supported a priority, then get a 2.2kW spindle when you can afford it. The 2.2kW spindle is better since it uses larger (ER20) collets and will get marginally better power at low speed.
I still don't think that machine is a good price considering the total cost of the components bought from China, but it's hard to suggest anything better without saying make it yourself.

Thanks Jonathan,
That gives me some hope. I have managed to get the price down to 1400 euros now. (considering it going to cost him 200 euros to send it to me) . I am still considering the Chinese 6040 with 2.2kw wc Spindle. But I just don't like the idea of that. Everything I have ever bought from China needs bits replacing every other month.
By looking at the Picture I have posted earlier in this thread, would you say changing those rails is possible without major work or fabrication (it is just bolt on parts) ? What sort of money are we talking of here ?

Attachment 7162
Ok, he has sent me a photo of ali he has machined today. Youtube video later today I'm told. I might then get to see some of what this machine is capable of.

Hard to tell from the resolution of the picture but seems to me the finish is useable but not great. Would be interesting to see the video and get some idea of the machining time and the tooling used.

I have now got the youtube video of the machine cutting a small circle in Alu

http://www.youtube.com/watch?feature...;v=nv2PWG4l8aU

Attachment 7281Attachment 7282Attachment 7283

I have chosen to buy this machine. I know it would have been better to build one for the amount of money spent, but I wanted a working machine that I could improve as I go. I understand it is never going to be a high performer.
My question is please.....do I buy a Kress 1050 FME to replace the very underpowered 250w spindle that exists on the machine, or do I change the Z plate and buy a Chinese water cooled 2.2kw spindle ?
Is there anyone online who fabricates and sells the Z plates/clamps to make the Chinese spindle fit my machine ?