[Lomax1]

So I still haven't got my much dreamed of CNC machine, and I find myself coming back again and again to look at what might be possible. I want one so bad, but it is difficult for me to be able to afford a complete X6-1500GT-USB - and saving up has never been my forté. This got me thinking about the possibility of buying a CNC router as parts, which would allow me to spread the cost a little. Just to see whether this might be a realistic option, I decided to have a look at some prices, so I could compare the cost to a complete machine. The result is that it looks surprisingly cheap! This uses the same stepper drivers, spindle and VFD as the X6-1500GT (I think) - but it has more powerful steppers and a better controller! What do you guys think?

Buying as separate parts: 

1x YooCNC 6040Z-S80 Mainbody            $1300
1x Ethernet SmoothStepper                $200
1x 48V 600W power supply                 $150
3x Nema 23 4.2A & DQ542MA 50V            $250
3x Nema 23 mounts                         $60
1x 1.5kW spindle & VFD                   $300
1x Cooling pump                           $40
---------------------------------------------
                                        $2300
Benefits: 

 - Cheaper
 - Better steppers
 - Better controller
 - Payment can be spread out



Buying as complete machine:

1x YooCNC X6-1500GT-USB                 $2590
---------------------------------------------
                                        $2590
Benefits:

 - Less hassle
 - ???

All the prices include shipping but not the customs fees, and I haven't included the cost of cabling, connectors or enclosure. I've rounded the figures up a bit to be on the safe side. Did I miss any essential/expensive bits? Any other reason why this might be a bad idea?

[Lomax1]

100 views and no-one has anything to say? I wonder if that means it's so obviously the right thing to do that it's not even worth commenting on - or the exakt opposite!

[slaith]

Well the only real difference is the smoothstepper board?

I personally would use PoKeys57E as a breakoutboard and their PoStep25-32 driver.
Cheaper, but still looks like a solid product and it has been used with the 6040 I remember reading somewhere.

You might use the option of bying the steppers at the same time as the mainbody, they are good and you get couplings and mounts at the same time.

I don't se that you calculated for cabling or tubing for the cooling?
Remember that shielded cable for the Spindle is needed, but it should be changed from original anyhow so that a moot point.

And you have to make somekind of housing for the electronics plus connectors and I/O.

It might sound like i'm trying to shoot down the first option, but that is not the case at all.
That is in retrospect the route I should have taken.
Because as well built as the driver electronics box is, it still leaves alot to be desired.
And the fan speed is way to high which means it sucks everything into the box, plus it sounds like a jet enginge.

I for one would really like someone go down this path, I think this would make for a better solution in the end.

Hope that helps somewhat.

Best regards
Patrik

[Lomax1]

Hi Patrik,

Many thanks for your helpful reply! It's great to get some confirmation that my idea is indeed valid, and that there are no "show stopper" reasons why I shouldn't do it.

Regarding the controller board: I would like the Ethernet SmoothStepper mainly because it uses a network connection rather than USB (which offers some intriguing future possibilities) and because it has an abundance of I/O connections (again, because of the future possibilities this offers). It has also got a very good reputation as a solid controller! The $200 it costs (with shipping) is small potatoes in the greater scheme of things.

Regarding the steppers: I found a package on eBay for three 4.2A Nema 23 steppers which includes three drivers (DQ542MA) for $250 - these are bigger steppers than the ones YooCNC offer (those are only 3A models), and I thought this might be a good thing, mainly because of the higher holding force they offer? I believe the DQ542MA drivers are the same as the ones which ship with the X6-1500GT-USB and I would be very interested to hear if there is a better option in the same price range. The Gecko 540 integrated controller/driver might be an option here, although it lacks the ethernet connection?

Regarding the stepper mounts: those sold by YooCNC are plastic and the ones I looked at were made from machined aluminium - which should have less flex and be more durable - though I'm not sure if this makes any meaningful difference, other than that it looks better Am I understanding things correctly that the stepper mounts are a standard size and that pretty much any "Nema 23" mounts will fit the frame?

Regarding the housing: I think I would prefer to get a wheeled metal cabinet of some sort that is large enough (100x80cm top surface should be enough?) to place the 6040 frame on top of, with room to spare for erecting a sound/dust hood and coolant tray around the machine (I will have this machine in a domestic setting). All the electronics would be mounted inside the cabinet underneath the machine and therefore shouldn't need any further enclosure. In fact, the cabinet would probably be the first thing I buy, so I can plan the location and start building the hood before the body arrives, otherwise I won't have anywhere to put it when it gets here!

Regarding cabling etc: This shouldn't add too much to the cost, and I don't want to preempt exactly what cables/connectors/switches etc I will need. As you point out I would probably need to replace the cabling/tubing that comes with a X6-1500GT-USB anyway. Chances are I already have some of these parts, like cooling fans, connectors, switches and cables - I am a prolific collector of bits

Thanks again for your input!

[slaith]

The pokeys is Ethernet too.

I haven't noticed any slip from either the motors or couplings.
Nor the mounts flex anything that i can see, but machined alu looks way cooler in my opinion.

Put the electronics in a closed box with fans using filters, otherwise it's gonna collect alot of dust over time.
I have a metal table for my CNC that is around the size that you describe, will probably build a hood for it when i start milling alu.
Because with a fogbuster type of coolant, the chips will be all over the place.
Plus for eventual dust evacuation you can use the roof of the hood to route pipes from the dust boot to the vacuum hoze.

Buy cables that is very soft and properly shielded, like Ölflex cables.
Or something similar.

By the way is there any other companies selling just the shell of the CNC without drivers?
Mainly because the portal linearguides is flexing a little when you go hard inte something.

[Lomax1]

Thanks slaith, many valuable hints there! I knew PoKeys sounded familiar somehow - I have seen some early version of this device, though not in the context of CNC control - they look very useful indeed! I worried at first that one would have to do a lot of programming to use it with Mach3, but I see that there is a plug-in available. Great price at just €50 as well! Ok, so that would shave another $100 off the cost then!

When it comes to the table/cabinet, I'm thinking something a bit like this:

Attachment 248406

That one is 120x60cm, so not quite perfect (and it is also horrendously expensive!) - just a quick photo find to give you the idea. The cabinet part would be the electronics "enclosure" and a hole (with filter) could be cut in the side for the fans. No futher enclosure would be needed, and access to the boards is as simple as opening a door Plenty of room for spare parts, cutters and whatever else - it's always nice to keep all the things that belong together, well, together!

By the way is there any other companies selling just the shell of the CNC without drivers?

You know I've wondered the same thing, but I haven't been able to find anything - I know you can buy a 6040 type machine on eBay for about £1000 ($1600), but they come complete with crappy controller, crappy drivers, crappy Ø60mm spindle and spindle mount, etc etc - I have no reason but to assume that the rest is as crappy too; probably lead-screws with nylon anti-backlash nuts and so on. YooCNC seem in a completely different league, and since I've been drooling over their machines for 1 1/2 years I've seen that they evolve, learn and listen to their customers. I'd much rather trust them with my hard-earneds; kudos to them!

Mainly because the portal linearguides is flexing a little when you go hard inte something

I assume you mean the Z-axis here? I can imagine there will be some flex, particularly when milling close to the X-axis center line. But what can you do about that, other than spend another $3000 on top to get a professional machine? Not an option.

Durability wise, I don't really see myself pushing any limits; main uses I foresee for mine are: PCB prototyping, front panel engraving, small part making (like replacement bits for broken plastic mechanisms etc), 3D "printing" (subtractive, of course!) in MDF, light cutting of alu and perspex sheeting, vinyl cutting and stencil making (with a drag knife), matte cutting for photo mounts (also with some kind of knife), photo gravure experiments (excited about this!), and about a million other things... the list is long, but they're all pretty light tasks and it's not going to see 5d8h use or anything like it! In fact, it would probably only be used a handful of times in a month - which is why it's so hard for me to justify the cost! My hope is that I get the right machine the first time, that I won't have to spend any more, that it does the things I expect from it, and that it lasts very long time (side note: just refilled my Epson SP4000 - it has now done almost 3km paper and 17 liters of ink since new, still going strong!).

machined alu looks way cooler in my opinion

And let's not forget how important that is! To me it is anway

[slaith]

Yeah the Pokeys Actually seem like something really good.
And like you said it has a finished plugin for Mach3.
Plus it already has screw connector, but the smoothstepper only has those IDE kind of connectors for som reason.


A cabinet of that kind is perfect!
Put a filterholder in the bottom or lower part of the door, then a outlet fan at the top side.
That's how we do it in bigger cabinets in the industrial sector.
That way you get filtered cool air into the electronics, better circulation that way.

It also ha alot of drawers for tools, spanners and end mills.


About the flexing part:
I actually talk about the Y axis, the whole portal.
Because they don't use linearbearings with rails, you know the ones that looks like train tracks.
You have flex in the middle of the thing.
The Z axis if so short so it doesn't flex so much.

I use my machine in the manner that you describe, and for the money it's pretty good.
There are som points that could have been improved, but that would affect the price too.

I have been pushing the limits of it, running 3D milling at 6000mm/min and such things.
It can easily keep up, but you have to be aware of the flex in the machine.
Be prepared to fun the finishing pass att 500-1000mm/min to get a good finish.

Yesterday I made a holder for my collets and end mills, straight out I couldn't get any of the end mills in.
But modifing the program a hundred here and there and running it slow in the finishing pass.
Well it made for a really nice tight fit for the end mills.

Another tip is that you buy really sharp Carbide end mills.
Don't go cheap and get HSS or something.
Carbide cuts like butter through everything.
I managed to run my 6mm straight into an iron mounting screw at 2700mm/min and 24000RPM.
Lets just say that the head of the screw just turned into glowing red chips, and not a single dent in the end mill.


I find that this machine is a good middle way, sometimes I wish the envelope was a little bigger.
But not so often at the moment.
Besides I have linearguides and alu profiles to make a 120x240cm machine, but I have no place to put it at the moment.
This machine will be able to make the parts I need for that one later.

If I were you I'd just go for it!!

[Lomax1]

Yeah the Pokeys Actually seem like something really good. And like you said it has a finished plugin for Mach3. Plus it already has screw connector, but the smoothstepper only has those IDE kind of connectors for som reason.

And it's cheaper. We have a winner! And should one tire of CNC - or crash the machine beyond repair(!) - the Pokeys is sure to come in handy for something else. Also: agree 100-fold re. the connectors on the SmoothStepper; unfriendly design!

A cabinet of that kind is perfect!

Yeah, but unfortunately the one in the previous photo is >£800 ($1200) I've now had a thorough look around and the best price I can find for something similar is ~£400 - which is still too much for me. I'll either have to get lucky on the second-hand market, or think of something else. Shame, becuase that seemed like a superb solution

One idea that might work is to get two 12U rack units and place them side by side. That would yield a top surface around 110x90cm, about 65cm high, depending on the racks used. It would be easy to customise these with whatever doors/panels/drawers you want - progressively too, which is always a plus! I don't really see myself moving the machine around (my workshop is too small - and it won't go through the door) so I don't mind losing the wheels. I imagine a couple of sheets of 25mm MDF on top will eliminate a lot of noise and vibration, and the racks could be screwed together for additional stability. Even including some drawers and blank panels I think this can be done <£300, which is a lot more realistic than £800!

Attachment 248632
Attachment 248634

Put a filterholder in the bottom or lower part of the door, then a outlet fan at the top side.

Ah yes, good old "convection" - conventional but convenient!

That's how we do it in bigger cabinets in the industrial sector.

One of my first "proper" jobs was programming Yamaha industrial robots (or was it Honda ... my memory fails). So I've seen how "the big boys" do it first hand! At one point I even worked on fixing the embedded control system for the vacuum toilets(!) on the Swiss national railway - which had a tendency to malfunction in "interesting" ways... Many years now since I saw the inside of a factory though Don't seem to be that many around anymore, at least not in these parts...

About the flexing part: I actually talk about the Y axis, the whole portal. Because they don't use linearbearings with rails, you know the ones that looks like train tracks.

Ah, I think I get you; there is a sideways deflection, perpendicular to the direction the "portal" moves in? Because only the guide-rods and leadscrew keep it in place, and they're a bit bendy - especially around the middle? If that's the case, I would have thought it would be reasonably easy to add some guiderails to the chassi?

Be prepared to fun the finishing pass att 500-1000mm/min to get a good finish.

Time is always on the side of the tinkerer!

Yesterday I made a holder for my collets and end mills, straight out I couldn't get any of the end mills in. But modifing the program a hundred here and there and running it slow in the finishing pass. Well it made for a really nice tight fit for the end mills.

Then a few months later, on a cold winter's day, you need to do a bit of something - only to find you're unable to extract any of your cutters from storage...

Another tip is that you buy really sharp Carbide end mills. Don't go cheap and get HSS or something. Carbide cuts like butter through everything.

I fully expect to be back here with a million questions about stuff like this once I've got a machine... I've grokked that single flue carbide bits are the thing when it comes to alu on this machine though. PCB cutters are more complicated it seems. But hey; luxury problem!

If I were you I'd just go for it!!

Going!

[slaith]

A rack unit like that will do nicely, it will actually provide a really felxible base for the CNC.
Drawers, cabinets whatever you want to make of it.

I did som milling with a long 10mm end mill, and when running a slot the whole Z carriage started vibrating.
Almost jumping, because of the forces on the Y rails, I hade to hold it with my hands to stop it from vibrating.

So the gantry is definetly a weak point of the CNC, but it could be that I was running to slow and not loading the mill enough too.

Yeah the End mill board turned out really nice, made it from IKEAbeech cutting board.
I wouldn't be to worried about the winter here, because it's really dry and cold most of the time.

Do report back when you get going.

Keep the questions coming.

Good luck!