[Sundayforsammy]

Hi all,

I am totally new to CNC milling and have been searching and reading now all over the internet for about a week. Forgive me if this has been asked over and over again but there seems to be so much about this that I cannot work out what is best.

I am looking at buying a Chinese 3040 machine without any electrics instead of buying a complete machine as I wish to get the main gantry bit then add the electrics as I go.

Looking at the 3040 I will be trying to get the one with x,y,z 1204 ball screws.

When it comes to the electrics I was looking at 3 x nema23 270oz steppers with 3x DM542A drivers plus the PSU and parallel breakout card. I am a little unsure about these being the right things to add and if they are all I need (apart from a spindle).

The items I looked at are in this ebay listing
【German Ship】3Axis Nema 23 Stepper Motor 270oz-in &Driver 4.2A CNC Router | eBay

Any advice you can give is really welcome. There is just so much conflicting info and my brain is a little fried after reading up for a week. I have read about the GeckoG540 controller being the best route but at this stage I really don't have that kind of money. (one day maybe).

P.S. the use I want from this CNC is to mill Hammond Alloy enclosures, part of which would be to mill the cut outs for 16x2 LCD displays and 0.8mm recess for faceplate etc. (Hammond enclosures are 2mm thick so any cutting would never be large alloy billets.

Cheers
Mick

[Dennis Bohlke]

The motor shaft diameter can be an issue if they do not match between the 3040 and the motors you buy.

[Sundayforsammy]

Thanks Dennis,

I know the Nema23 motors I am looking at have 6.35mm shafts, I have not found out yet what the 3040 uses so will check on that before jumping in.

I am wondering about these DM542A driver modules , if they are suitable or if I would be better using single controller unit like TinyG or Arduino based shield or something else.

[Dennis Bohlke]

I have been eyeing the TinyG and Gshield myself. I have ported my firmware to the Arduino Due so that with the Gshield looks like a fun project.

Dennis
Super Tech & Associates

[jcarpenter2]

My 3040 came with 8mm shafts. You can buy couplers though that are sized 6.35x8mm if you don't have the ability to turn down the shafts to 6.35mm.

[A_Camera]

Hi all,

I am totally new to CNC milling and have been searching and reading now all over the internet for about a week. Forgive me if this has been asked over and over again but there seems to be so much about this that I cannot work out what is best.

I am looking at buying a Chinese 3040 machine without any electrics instead of buying a complete machine as I wish to get the main gantry bit then add the electrics as I go.

Looking at the 3040 I will be trying to get the one with x,y,z 1204 ball screws.

When it comes to the electrics I was looking at 3 x nema23 270oz steppers with 3x DM542A drivers plus the PSU and parallel breakout card. I am a little unsure about these being the right things to add and if they are all I need (apart from a spindle).

The items I looked at are in this ebay listing
【German Ship】3Axis Nema 23 Stepper Motor 270oz-in &Driver 4.2A CNC Router | eBay

Any advice you can give is really welcome. There is just so much conflicting info and my brain is a little fried after reading up for a week. I have read about the GeckoG540 controller being the best route but at this stage I really don't have that kind of money. (one day maybe).

P.S. the use I want from this CNC is to mill Hammond Alloy enclosures, part of which would be to mill the cut outs for 16x2 LCD displays and 0.8mm recess for faceplate etc. (Hammond enclosures are 2mm thick so any cutting would never be large alloy billets.

Cheers
Mick

Make sure you get the right coupler. Other than than, I am using similar drivers and they work excellently. The power supply I am using right now is only 24V switching supply, similar to yours, but will upgrade to 46V unregulated through a toroidal transformer. I am building the power supply, bought the parts from this company, called CNC-Plus. I believe the higher voltage will improve my speed.

I can't say much about the CNC itself, I designed and made my own, but if I bought one I'd buy a little larger one which uses linear rails and 1605 ball screws. It is important that the one you are buying does not use unsupported rods because that will cause you accuracy issues, vibrations and flexing. Make sure that the rails are supported, that's important. You must also have enough Z clearance. Most small CNC I have seen have only 50-70mm (2-2.5") Z clearance which may not be enough.

[Sundayforsammy]

Thanks for all these replies, they have been good and I have ordered a cnc3040 for now. I have gone for a complete machine and although I know I will be replacing all the electrics quite quickly at least I will be getting a working machine to build on, and the cost was only a little more than the basic frame. I will definitely be looking into a USB option.

The biggest issue is that at this price I am unable to find something that has a decent Z depth as mentioned ^

I am expecting the CNC to arrive sometime next week so will post info on how I get on with it as a total beginner.

[Sundayforsammy]

The CNC3040 arrived today and I was quite surprised that it was better than I thought it would be on unpacking, The delivery guy was a little worried when he brought it to the door and said he wasn't sure about what ha happened but the package had a lot of rattling going on inside so he said he would mark it down in his book as unchecked in case it was all broken. As it happened it was the stepper motor bolts that were loose inside the box rattling around.

As a lot of people have mentioned in many threads the table is very uneven so I will need to look up about how to level this all out. and other thing I must read up on as a newbie to the whole Cam/Cad world.

The machine came with Mach3 but I need some advice on what software I can use for designing 2d components for now and converting to G-code to be used in Mach3, I looked at Vcarve pro but that was nearly as costly as the whole cnc machine, so Free software for now would be a huge bonus as I still need to be spending money on electrics to get the CNC up to a decent spec.

I'm loving my first venture into CNC and I am sure to bugging you all with silly questions, after I spend time searching threads first of course.

Happy CNC Dude here with lots to learn

[aarggh]

Welcome to the world of CNC!

I suspect you'll quite enjoy your new machine until the bug fully bites in a few months and you then want a bigger machine! ;-)
cheers, Ian

[Sundayforsammy]

The bug has already started to bite, after doing a few learning/test millings to familiarize myself with how to get things working I am already looking at what to upgrade first, I can see this is going to get to be an expensive hobby but worth it.

I want to do the upgrades in stages but I ask for advice on what order to do the upgrades in from all the people from the cnczone forum. My intention was to first upgrade the spindle to a 1k5 or 2k2 vfd but would it be better go for water cooled or air cooled ? There seems to be different reports on quality of the Chinese spindles seen on ebay, especially about what bearings are used. The cnc3040 I have also has a spindle mount that is a one piece unit with the z axis so some thought about how to modify this to fit a larger diameter spindle is needed.

The other thing on my mind is I wanted to replace the stepper motors with some 4a nema23's before replacing the controller electrics but is it best to replace the controller first as the higher amperage the steppers require may burn out the existing controller ?

sorry for too many questions at once,

Cheers
Mick

[apt403]

To level the bed you could install a spoil board and mill it flat in relation to the spindle. That was my plan, however as of now the machine bed isn't too bad.

I've been thinking about the problem of the one piece spindle mount as well. While there is enough material that one could theoretically saw off the circular portion, mill it flat, and drill/tap holes for an adapter plate, I'm leaning towards reverse engineering the important section (the area where the linear bearings and ballnut seat) so I can have a 1 peice setup. I've got the advantage of a mill and lathe, however.

If it was me, I'd do the electronics first, but I bought a bare machine and added KL4030s and 280oz-in steppers from the get go.

[aarggh]

If you can't do them all at the same time, then I would most definitely get the new driver first, then look at the power supply, and then the spindle. For spindles I far prefer water cooled. Some like air cooled but I find most of the people running air cooled are running them in semi-industrial environments, in other words they have proper dust extraction.

Air cooled will be noisier, and will create dust swirls, so you'll need really good dust extraction to stop them clagging up.

cheers, Ian

[A_Camera]

The bug has already started to bite, after doing a few learning/test millings to familiarize myself with how to get things working I am already looking at what to upgrade first, I can see this is going to get to be an expensive hobby but worth it.

I want to do the upgrades in stages but I ask for advice on what order to do the upgrades in from all the people from the cnczone forum. My intention was to first upgrade the spindle to a 1k5 or 2k2 vfd but would it be better go for water cooled or air cooled ? There seems to be different reports on quality of the Chinese spindles seen on ebay, especially about what bearings are used. The cnc3040 I have also has a spindle mount that is a one piece unit with the z axis so some thought about how to modify this to fit a larger diameter spindle is needed.

The other thing on my mind is I wanted to replace the stepper motors with some 4a nema23's before replacing the controller electrics but is it best to replace the controller first as the higher amperage the steppers require may burn out the existing controller ?

sorry for too many questions at once,

Cheers
Mick

I can't help you with the "how to modify the spindle holder" part because I don't have that solution. Mine is DIY all the way and is my own design. Never the less, regarding your planned VFD upgrades are similar to mine. I am also planning to exchange my spindel and getting a VFD. I was in the same shoes, weighting water cooled against air cooled and considered between different powers. Finally I decided to go for an 0.8kW air cooled type for two or three reasons.

One is that it would provide much more RPM and power than my current 0.4kW low voltage DC motor can do. After all, 100% more power is a lot more, especially if you also add the fact that the RPM is also doubled. Not only that, but also the fact that these are using ER11 collets, which I have a lot of already and generally I am very happy with that size. Larger VFDs use ER16, so choosing a 2.5kW would mean that I'd have to buy a new set. I don't really have use for larger tools, at least not very often wish to have the ability to use larger than ER11.

The second reason is concerning air vs. water cooling. I went for air cooling mainly because I don't want to have a pump pumping around water in the room I am using my CNC. It is a dry room, I don't use any liquids during milling and I want the room to stay dry, don't want to risk leaking joints or hoses, don't want a water bucket under the CNC and don't want a pump constantly running when the spindle is running. OK, it may be so that the fan itself makes noise also, and that the fan will blow around the chips more than the one I am using now, but that's OK, I will make a dust extractor anyway, so I don't mind the blowing. I also don't think that the noise will be noticeably more compared with a water cooled one plus the running pump. I may be wrong, I tried to find some Youtube clips where air cooled are compared with water cooled ones, but I failed. I'd be very interested to see such clip, but in all similar clips they NEVER have the pump running and never fixed the motors the same way and never record the video with the same settings, most people use automatic volume features and move around with their cameras far too much, so I find most videos pretty annoying to watch. There is also risk for mold, or need to use chemicals to prevent it, and again, I don't want that inside the room I have my CNC in. So I decided for air cooled and believe it will be the best for me.

The third thing was weight and size. Larger VFDs are just too heavy and large for my need and taste. A 2.5kW weighs about 5kg and has a diameter of 80 or 100mm. I don't have needs for such large spindle on my CNC. The 0.8kW weights about half of that and is only 65mm in diameter. I have a very large Z axis, 150 x 250 mm, so for me it would be no problem, but this is very important for you, since your Z is very small. You must have a serious look at this and carefully consider if you REALLY need or want and REALLY can install and use such large VFD. The 5kg extra weight is really a lot, and the diameter of such large VFD needs a Z which is about the same width as mine, 150mm. It also needs a lot of clearance between the table and the Z plate.

So my own decision was clear, air cooled 0.8kW. But...

I have recently partially changed my mind. I realized that there are also air cooled 1.5kW motors with 65mm diameter, using ER11 and just weighting a little more than the 0.8kW, so I will buy one of those. I have not yet made the order, but will do it soon. I am not worried about the fact that those are Chinese, I really don't believe in horror stories. Yes, things can happen, but considering the number of sold items, I think they are just fine.

[A_Camera]

If you can't do them all at the same time, then I would most definitely get the new driver first, then look at the power supply, and then the spindle.

I definitely agree with that order of priority. The only additional, even more important thing I'd do is checking the frame and adjusting/squaring every axis. I'd start with that before spending time and money on anything else.

For spindles I far prefer water cooled. Some like air cooled but I find most of the people running air cooled are running them in semi-industrial environments, in other words they have proper dust extraction.

Air cooled will be noisier, and will create dust swirls, so you'll need really good dust extraction to stop them clagging up.

I think that water cooled are at least as noisy as air cooled if you take the pump into account as well. Of course, to really KNOW the answer I'd need to take two equally powered motors, one air one water cooled and run them side by side, with the pump running and pumping water. It would be an interesting experiment but a bit expensive. I have no use of two spindles so it is difficult to motivate the costs. Other than that, the dust issue is maybe more of a problem for those who are working with wood and MDF than for other material, but sure, a good dust extraction is important, not only for the dust itself, but also for removing chips so that they are not milled and sliced twice, creating surface accuracy problems.

[aarggh]

I think that water cooled are at least as noisy as air cooled if you take the pump into account as well.

I've had both and sold the air cooled as it was just too noisy, fans really just suck, and the dust swirls was a massive inconvenience. Crap got blown just everywhere using it no matter how good the extraction was. So far as noise you'd have to buy a pretty crap water pump for it to make any really noticeable noise.

My pumps are bog standard el cheapo Chinese ones ($15-$20 range), and sit submerged in a tub of coolant at the end of the machine, and all you hear is a very soft hum. If you used a non-submerged pump I could see that would make a lot more noise, but I just reckon air cooled for most home/hobbyists environments isn't practical unless your happy with the mess that comes with it, or spend a small fortune building very efficient dust extraction systems. The spindle being so quiet I can happily use it till the very late hours without annoying the neighbours. Not so with air cooled.

I've been machining a lot of HDPU of late, and that creates an amazingly fine and slightly abrasive dust that clings to everything, I'd hate to think what my workshop would look like using an air cooled spindle with that!

cheers, Ian

[Sundayforsammy]

I'm convinced, water cooling is the way to go. I think I can also use the existing spindle to make the parts needed to modify the spindle holder using HDPE and then use this temporary to fit the 1k5 spindle and then mill the same parts in alloy for the final parts. Does this sound reasonable to do.

[aarggh]

I'm always in favour of bigger and better, but the 3040 is a pretty small machine, I don't know how well it will drive a 1.5kw spindle which tend to be 80mm diameter, they are fairly heavy, unless it's a slimline variety?

On my 6040 it came with a 65mm water cooled 800w spindle which was almost kinda borderline weight wise I thought for the machine construction and steppers, but it did perform really exceptionally well. I've even done heaps of fairly grunty aluminium machining using it.

Given your machines size, an 800w spindle may be a better solution possibly?

cheers, Ian

[A_Camera]

I've had both and sold the air cooled as it was just too noisy, fans really just suck, and the dust swirls was a massive inconvenience. Crap got blown just everywhere using it no matter how good the extraction was. So far as noise you'd have to buy a pretty crap water pump for it to make any really noticeable noise.

My pumps are bog standard el cheapo Chinese ones ($15-$20 range), and sit submerged in a tub of coolant at the end of the machine, and all you hear is a very soft hum. If you used a non-submerged pump I could see that would make a lot more noise, but I just reckon air cooled for most home/hobbyists environments isn't practical unless your happy with the mess that comes with it, or spend a small fortune building very efficient dust extraction systems. The spindle being so quiet I can happily use it till the very late hours without annoying the neighbours. Not so with air cooled.

I've been machining a lot of HDPU of late, and that creates an amazingly fine and slightly abrasive dust that clings to everything, I'd hate to think what my workshop would look like using an air cooled spindle with that!

cheers, Ian

Interesting. Thanks for the comment. Yes, definitely if one works with foam or any kinds of wood or MDF then water cooled is the way to go. I am mostly working with POM and other type of plastics, currently using air cooled spindle which spins at maximum 12k RPM and is only 0.4kW. Never the less, perhaps I will reconsider also. What is the size of air and water cooled motors you have? I considered 800W first, because of the weight but then I found 1.5kW in the same weight and size class, so I will probably go for that one, but I am a bit concerned about air vs. water cooling and also about the chemicals needed in the water cooled one to prevent mold, after all, mine is not used often and is not in a well vented shop but more in an office like, home environment with wooden floor, so any leakage would not be welcome. You are though probably right about the pump, a submerged pump should not be very noisy.

[aarggh]

Interesting. Thanks for the comment. Yes, definitely if one works with foam or any kinds of wood or MDF then water cooled is the way to go. I am mostly working with POM and other type of plastics, currently using air cooled spindle which spins at maximum 12k RPM and is only 0.4kW. Never the less, perhaps I will reconsider also. What is the size of air and water cooled motors you have? I considered 800W first, because of the weight but then I found 1.5kW in the same weight and size class, so I will probably go for that one, but I am a bit concerned about air vs. water cooling and also about the chemicals needed in the water cooled one to prevent mold, after all, mine is not used often and is not in a well vented shop but more in an office like, home environment with wooden floor, so any leakage would not be welcome. You are though probably right about the pump, a submerged pump should not be very noisy.

If you can get a 1.5kw spindle in the same weight and size class as an 800w, then definitely go for that! It means you're well over specc'ed so it will never be straining.

So far as pumps go, I wouldn't even consider anything but a submerged one not only because of the noise, but also the longevity of the coolant being exposed to light and contaminants. I've bee running my big 6090 machine with a tub of reasonably good quality and undiluted car radiator coolant for some years now. The tub sits at the end of the machine on the floor, but I've closed off the entry and exit points to a fashion, and then covered the whole thing with a thick towel. The enemy of the fluid you use to cool the spindle is exposure to light and dust. as mine is a very cheaply made "closed loop" fluid system it's still the original 6 litres of coolant, I check it every years or so, and so far it's as good as new. No blooms, growths, or lumpy bits anywhere.

I see a lot of people on the zone agonising over water cooling systems but it really is about the simplest part of cnc, so long as you have a decent size reservoir that's protected from light and contaminants, and you don't use cheap rubbish, it'll pretty much last forever. It is designed after all to work in the extreme environments of cars with varying types of metals with no ill effects.

I can leave my machine run for 18 hours at a time, in summer, and in OZ we get some pretty fierce hot days, and with just the 6 litres, the spindle rarely gets above a little warm. No fans, no complicated radiator and pipe setups, just a big bucket of coolant with a towel covering it.

cheers, Ian

[A_Camera]

Thanks Ian. I will have a more serious look at the possibility of water cooled spindle.