-
Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Hi everyone.
I am pretty new to CNC and milling but I have a couple months to learn.
Been watching a lot of videos on YouTube so starting to build up a bit of basic knowledge.
My project requires a case for the electronics and sensors as well as mounting fixings.
I have been developing it using 3D printing and I was originally going to manufacture the cases this way but while I am okay with this for my own use, selling it as a product for people to use I am not so keen on.
So I am looking at using a CNC milling machine to make the case instead so it is a nice solid product.
Why not aluminium? Well we are using wireless transceivers inside the product so metal is out of the question.
My idea is to then use 15mm polypropylene sheet instead to get the same sort of light wight properties and strength (small sized case, about 100x45mm).
Are these China CNC milling machines okay for this?
I have seen them eat 10mm aluminium so this should be fine right?
My understanding of milling plastic is speed and sharp tools to reduce heat and thus the plastic melting.
There is less horse power needed as it is more speed than anything, though I still want a powerful spindle for future proofing..
I am also looking at the 6040 over the 3040 for future larger projects.
Software wise I use 123D Design for modelling the case.
For the CNC I plan on using Mach4 for controlling and Fusion 360 for the CAD stuff.
I understand that the controllers that come with the China CNCs are pretty, crap though they get the job done.
So was thinking of getting something like a TinyG right off the bat.
I am pretty good at electronics, I designed the circuitry for this product using micro controllers and built and customised a 3D printer so wiring up a new controller is fine with me.
I am aware that these China machines don't have end stops. So would be adding them as well.
Am I on the right path here?
As for hardware, I am stuck between ordering a complete package and picking things individually.
My thinking, ordering something like http://www.ebay.co.uk/itm/EU-Stock-4...QAAOSwDFNWFJQE would be best for just getting everything I need.
Or do I order everything separately so I can get the upgraded spindle and not pay for the controller if upgrading to the TinyG is much better than using stock?
I am sure a lot of this has been asked before. I have done a bit of searching but thought it might be worth just posting and seeing what people say.
Thanks
Jack,
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
The best plastic for machining is hard polyurethane. Thermoplastics and nylon tend to string, acrylic melts and then congeals around your tool. If you are thinking to machine plastic, try a chunk of Tufset or similar. Mind you, it will spoil you for anything else.
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
I love machining Acetal, it chips beautifully gives a nice smooth finish. Cant comment on the Ting G controller but if this is potentially for business then I'd build your own control panel, make your own PSU etc. etc. You'll be updrading the 6040 after a while so at least you'd have decent electronics...
Sent from my HUAWEI VNS-L31 using Tapatalk
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
I was looking at this stuff. https://www.cutplasticsheeting.co.uk...-polypropylene
Cost wise it is perfect and I can get it in good little custom sized sheets that will do one case each.
Googled "hard polyurethane" but not seeing much. Got some more info on that Robin?
Not heard of Acetal before, though I am no plastics expert :p
Will take a look at it.
I would like to encase the machine once I get it all setup and working though this will be after the production run due to limited time.
Plan on having it in a tower case like a HAAS milling machine mainly so it is all self contained and can be plugged in and turned on.
Moving house soon so having it like that will help with storage and keeping stuff clean.
My main thing about the electronics is having it sort of reliable long term.
I would like to just be able to turn it on and not have a problem that then takes a day or a week to fix because the China circuit board decided to blow up or drivers die...
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Have a look at https://www.directplastics.co.uk/engineering-plastics/ they have lots of plastic stuff there [emoji2]
Sent from my HUAWEI VNS-L31 using Tapatalk
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Quote:
Originally Posted by
njhussey
Ah nice, thanks.
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Hello Jack
If I understand correctly, you have a project that you are now ready to commercialise. This will require manufacturing of plastic electronics housings and mounting brackets, for which you are considering cnc milling as the manufacturing method.
I would just suggest at this point that this possibly not commercially sound, and that you should consider vacuum forming, injection molding (or other plastic molding process), or closed mold GRP, etc. You may also consider purchasing an existing enclosure from one of a multitude of manufacturers/supplier of cheap enclosures.
CNC milled plastic may be commercially viable for simple flat profiles, or if only small quantities are required, but for example, an electronics enclosure (even a small one) milled from thick stock material has a high degree of material wastage.
Having said that, you may still need a CNC router for assisting to make your prototype vacuum forming molds and/or composites molds, which would typically be made in wood or aluminium. Another option, using your 3D printer, is that you could 3D print molds/patterns for brackets/boxes/etc then take composites molds from the printed models. You can also send 3D printed models of molds to an investment casting foundry and receive back an accurate aluminium or steel casting ready for prep/use as your plastics/composites mold.
I would recommend looking at vacuum forming, as it is quite simple, especially for small parts.
Regards, Jono
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Hi Jono
My case has 5 PCBs in it in different orientations and types of mounting as well as fixings for mounting onto tripods (technically for injection moulding but work fine when heated and pressed into plastic).
I have looked at injection moulding but the starting costs put me off quite a bit.
And vacuum forming and off the self cases wont work because of the requirements of the internal layout.
The case is basically two flat 15-16mm sheets pushed together with their internals milled out for the PCB, sensors and connectors.
Works out at around £5 per case using Acetal and £1 using Polypropylene. So material cost is not a problem with these solutions.
This is why I am aiming for milling because it should give me the quality people are after with a product as well as it being at a low price point similar to the 3D printing solution.
Unless if I am missing something here? xD
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Well it's certainly a lot more viable for low scale production than 3D printing is... It all comes down to how much volume you are expecting.
Injection tooling is indeed pretty expensive, only really makes sense if you are selling relatively high volumes and can spread the cost against at least several thousand units. I didn't pay for it myself but when we had the tooling made up for a drone I designed I think it was in the order of $10,000 to get the molds made (in china).
You would probably find a CNC a useful addition even just from a prototyping stand point - 3D printers are great, but the ability to work with PCBs, a variety of plastics, composites and some metals opens up more options to you that might be useful... not to mention much faster for making most things.
6040 is very much a generic term - some manufacturers are better than others, especially on the electronics front... One advantage of just buying a frame and adding your own electronics is that you can buy some better kit which you can then transfer to another machine if you decide you need something bigger or better.
I would recommend that you go for one with proper profile rails (e.g. HG20) rather than round rail - they are far superior. That particular machine you linked to actually simply has completely unsupported round rail for the X-axis gantry - don't bother with that... I had a similar machine in the past and there is a significant amount of flex from that design even when just pushing the spindle with your hand.
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Hello Jack, you've obviously done your homework on that stuff, and your part/design/method sounds to be even quite elegant.
Re injection molding, tooling should fit in a $5k envelope I would have thought, especially if your 'half shells' can be a mirror of each other, i.e. a single part.
Regards, Jono
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Spent a few hours looking into control boards and stuff.
People where saying the parallel boards that come with the China CNC machines are not worth it (because they are limited to just doing stepper control) so I would rather not use them.
Boards like the TinyG are controllers in themselves (I thought they worked with Mach3, bad YouTubers misleading me there), they don't run with software like Mach3 because they are hardware controllers.
They take the Gcode and control the motors, while Mach3 is a softwarecontroller that sends the movement data/signals to the drivers directly via serial or other interface.
I think what I am after is one of these "breakout boards".
This one (which comes with a lot of the stepper kits) http://www.ebay.co.uk/itm/262849334835
http://g03.a.alicdn.com/kf/UT88VGFXe...dXXagOFbX5.jpg
Looks to be what I am after.
4 Axis (only need 3) stepper control, spindle PWM, 3 relays for pump, air etc, home/limit switches and a couple IO ports.
Still China made but it comes with the motor kit so it should work fine with that setup.
Quote:
Originally Posted by
Zeeflyboy
It all comes down to how much volume you are expecting.
That is the thing. I am not expecting more than 100. Probably not even 50. But at least 25 to make it worth doing the production run.
I have always wanted a CNC table/mill. I want to do a few personal wood projects and some 5-10mm aluminium plate and I think now is a good time to get one.
That rail is a concern. There have been a few videos demonstration this but for what I am doing I don't think it will be that bad?
Most said it was okay though larger jobs it started to cause problems.
I really do like the idea of putting a kit together rather than buying a premade one.
http://www.ebay.co.uk/itm/EU-Stock-4...QAAOSwDFNWFJQE
This one looks the the standard 6040 and is around ~£1,500
But I could put together this kit together for around £1,200. But I get the upgraded 2.2kW spindle, controller and beefer steppers.
Base - £650 - https://www.aliexpress.com/item/6040...308.0.0.4cDNN7
2.2kW spindle/driver - £200 - http://www.ebay.co.uk/itm/252593036650
Steppers - ~£230 - https://www.aliexpress.com/store/pro...612.0.0.NtqLm6
Stepper mounts - ~£15 - Trying to find some EU stock. Only China atm :/ https://www.aliexpress.com/item/3Pcs...999.268.f7AXAm
Cables, Water pump, Tube, cable bendy thing etc - ~75-100
Sounds like a better deal to me...
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
The problem with "kits" of parts, especially electronics is that they are not well matched. The stepper motors will probably be high inductance ones, the switch mode PSU will be underated and so it wont run as well as it should. You'd be far better off getting your motors from Zapp or somewhere like that where they'll be good ones.
As. You're electrically minded building a custom P S U should be a breeze...
Sent from my HUAWEI VNS-L31 using Tapatalk
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Quote:
Originally Posted by
njhussey
The problem with "kits" of parts, especially electronics is that they are not well matched. The stepper motors will probably be high inductance ones, the switch mode PSU will be underated and so it wont run as well as it should. You'd be far better off getting your motors from Zapp or somewhere like that where they'll be good ones.
As. You're electrically minded building a custom P S U should be a breeze...
Sent from my HUAWEI VNS-L31 using Tapatalk
Ill take a look at the Zapp stuff, thanks.
As for the power supply, if I get my motors from Zapp I can get an OP supply.
Those Chinese switch modes are pretty good though. I have a 12v one powering a lot of stuff in my workshop 24/7 as well as my 3D printer and CCTV system.
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
The switch mode ones don't take back EMF from the drivers when the machine is decelerating. If you make a linear PSU with some nice big caps then this is best, and you can make it to the ideal voltage. You really want some nice 80V drivers and a 72V PSU...then it'll fly which is what you need to cut plastic. I cut UHMWPE at 8000mm/min, your matched set wont get near that.
Sent from my HUAWEI VNS-L31 using Tapatalk
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Quote:
Originally Posted by
njhussey
The switch mode ones don't take back EMF from the drivers when the machine is decelerating. If you make a linear PSU with some nice big caps then this is best, and you can make it to the ideal voltage. You really want some nice 80V drivers and a 72V PSU...then it'll fly which is what you need to cut plastic. I cut UHMWPE at 8000mm/min, your matched set wont get near that.
Sent from my HUAWEI VNS-L31 using Tapatalk
Hmm good point.
I am not too good with power supplies. As in making them. I typically just get off the shelf.
Have you made your own?
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Yes, have a read through the build logs...plenty have done them.
Sent from my HUAWEI VNS-L31 using Tapatalk
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Quote:
Originally Posted by
JOGARA
Hmm good point.
I am not too good with power supplies. As in making them. I typically just get off the shelf.
Have you made your own?
There are only 3 main components (toroidal transformer, rectifier & a couple of caps) or you could buy one from Zapp
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Isn't there a way to dump excess power coming back from steppers?
Like resistors or something.
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Quote:
Originally Posted by
JOGARA
Isn't there a way to dump excess power coming back from steppers?
Like resistors or something.
Unfortunately not. There are two main problems with the switch-mode PSUs in this application, although they are great and very cost-effective elsewhere. One is the back emf issue as mentioned, while linear power supplies dump excess power into the smoothing caps (one way to look at it, anyway). The other is that linear supplies are much more tolerant of peak overload. A switch-mode supply tends to hard-limit, maybe even shut down temporarily, if you try to draw more than rated current where a linear supply output will tend to just sag a bit which is not usually a problem. If you are now looking at Mach3, you might also consider something like a UC100 or UC300 with UCCNC which is looking like an attractive option these days. Still need a break-out board but it's a better option than using Mach3 and parallel port.
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Okay, so I looked into toroidal based supplies and they are easy to make. So should be no time to spin a board for one of those.
Do cost a bit to get them off the self, though I know of a place that do them for like 50 euros each at any spec you want.
So might be able to get a decent high amp one for not that much more.
The problem is, the high voltage stepper controllers are not Chinese cheap :p
Looking at £110 per axis :/
I have only looked on Zapp though so far.
Steppers themselves are around £30 each. Makes it around double the cost.
But I guess it is worth it because of needing that extra speed and power?
Regarding the steppers, they state a "Rated Voltage" of around 2-4v.
Do the drivers lower to voltage or because they pulse the stepper they are able to use upwards of 80v?
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Ignore stepper voltage ratings. As you say, the stepper driver effectively pulses the drive voltage; the driver manages the current rather than voltage but the higher voltage allows higher current pulses which helps develop torque. Confused me at first but the stepper driver will have an adjustable current setting which is more useful. That's also why you use a linear power supply - better current pulse capability.
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Quote:
Originally Posted by
Neale
Ignore stepper voltage ratings. As you say, the stepper driver effectively pulses the drive voltage; the driver manages the current rather than voltage but the higher voltage allows higher current pulses which helps develop torque. Confused me at first but the stepper driver will have an adjustable current setting which is more useful. That's also why you use a linear power supply - better current pulse capability.
Thought it was along that line.
As for picking what steppers to get.
Higher amp rating, higher holding torque are what to look out for?
Looking at Zapp, http://www.zappautomation.co.uk/elec...per-motor.html
The drivers; http://www.zappautomation.co.uk/elec...ion/em806.html
Looks to be the best at the £100-120 option.
80V and 8.2A.
Wondering what controller to get too..
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Quote:
Originally Posted by
Clive S
Didn't think to look elsewhere.
Thanks
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
One important thing to look for (and the cheaper stepper motors available online often fail this criterion) is inductance. High inductance may give high torque, but it slows the rate of rise of current through the motor coils which means that the rate of torque increase is also slower. That means that they are OK at slower speeds but with higher speeds/faster pulse rates, the torque drops off. The motors I'm using are 8-wire so that the coils can be wired in series or parallel. Series means lower current but poorer high-speed performance; parallel means higher current draw but better high-speed performance. This is all a bit of a simplification but it's broadly true and why you don't want high-inductance motors if you want to run fast. Does mean bigger PSU and drivers to suit the higher current.
I'm using the Zapp 3Nm NEMA23 motors on a 1500x750 cutting area router. Fairly heavy gantry (maybe 75kg?) driven by two motors and 5mm pitch ballscrews. I'm limited to about 5000mm/min by whip in the ballscrews (I should have used 10mm pitch) but those motors seem to drive that load without problem. I'm also using EM806 drives (from Zapp). I wanted newer digital drives, even though I had some appropriate rating older analogue drives from the Mk1 router, because, apart from generally better performance, they have stall detection. With a dual-motor master/slave axis drive on X, you really, really, don't want one motor to stall while the other keeps running. That could get very messy. I have wired the fault detect signal from the drives back to my motion controller so that if one drive trips, the machine stops very quickly. While setting up and tuning, this happened a couple of times which gives me some reassurance that the system works. I run on about 68V and have wound the motor max current setting to a point that it seems to run reliably on load without overheating the motors. The EM806s are well within their ratings although I have a couple of fans blowing a gentle draught across them.
For motion control, I went for Mach3 and a CSMIO IP/M ethernet controller. It's probably about the best controller around (based on general feedback and reputation) unless you go for its big brother the IP/S which costs about twice as much. The IP/M is not the cheapest option, although once you add in the fact that with "lesser" motion controllers you also need a breakout board, and a decent one that includes spindle speed control is not cheap, it's not that bad. It also uses 24V for signalling which gives better noise and interference rejection compared with 5V systems, and has differential outputs to drive the stepper drivers - again, this is an unusual feature but gives better interference rejection. I fitted mine, wired it all up, and it just worked first time, no messing about. The down side is that the IP/M can drive a master-and-slave axis machine like mine, but it cannot properly home the two axes. In practice, I am finding that this is not a problem and I have a simple manual workaround for this. If I were starting again today (I bought the electronics a couple of years ago), I might consider the UCCNC UC300ETH instead which is a cheaper option and getting a fairly good write-up in forums like this one. Haven't played with one myself though. You can save money by not needing Mach3 and using the UCCNC software which is also getting good feedback. All the same, I'm pretty happy with what I have.
But there are as many opinions in this area as there are CNC builders, so take all my comments as one man's view!
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Quote:
Originally Posted by
JOGARA
Didn't think to look elsewhere.
Thanks
As Neale has pointed out he is using the EM806. Both the AM882 and EM806 have stall detection which is a must when using two motors on one axis. I use the AM882 on my router and not had any trouble with them.
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Quote:
Originally Posted by
Neale
One important thing to look for (and the cheaper stepper motors available online often fail this criterion) is inductance. High inductance may give high torque, but it slows the rate of rise of current through the motor coils which means that the rate of torque increase is also slower. That means that they are OK at slower speeds but with higher speeds/faster pulse rates, the torque drops off. The motors I'm using are 8-wire so that the coils can be wired in series or parallel. Series means lower current but poorer high-speed performance; parallel means higher current draw but better high-speed performance. This is all a bit of a simplification but it's broadly true and why you don't want high-inductance motors if you want to run fast. Does mean bigger PSU and drivers to suit the higher current.
I'm using the Zapp 3Nm NEMA23 motors on a 1500x750 cutting area router. Fairly heavy gantry (maybe 75kg?) driven by two motors and 5mm pitch ballscrews. I'm limited to about 5000mm/min by whip in the ballscrews (I should have used 10mm pitch) but those motors seem to drive that load without problem. I'm also using EM806 drives (from Zapp). I wanted newer digital drives, even though I had some appropriate rating older analogue drives from the Mk1 router, because, apart from generally better performance, they have stall detection. With a dual-motor master/slave axis drive on X, you really, really, don't want one motor to stall while the other keeps running. That could get very messy. I have wired the fault detect signal from the drives back to my motion controller so that if one drive trips, the machine stops very quickly. While setting up and tuning, this happened a couple of times which gives me some reassurance that the system works. I run on about 68V and have wound the motor max current setting to a point that it seems to run reliably on load without overheating the motors. The EM806s are well within their ratings although I have a couple of fans blowing a gentle draught across them.
For motion control, I went for Mach3 and a CSMIO IP/M ethernet controller. It's probably about the best controller around (based on general feedback and reputation) unless you go for its big brother the IP/S which costs about twice as much. The IP/M is not the cheapest option, although once you add in the fact that with "lesser" motion controllers you also need a breakout board, and a decent one that includes spindle speed control is not cheap, it's not that bad. It also uses 24V for signalling which gives better noise and interference rejection compared with 5V systems, and has differential outputs to drive the stepper drivers - again, this is an unusual feature but gives better interference rejection. I fitted mine, wired it all up, and it just worked first time, no messing about. The down side is that the IP/M can drive a master-and-slave axis machine like mine, but it cannot properly home the two axes. In practice, I am finding that this is not a problem and I have a simple manual workaround for this. If I were starting again today (I bought the electronics a couple of years ago), I might consider the UCCNC UC300ETH instead which is a cheaper option and getting a fairly good write-up in forums like this one. Haven't played with one myself though. You can save money by not needing Mach3 and using the UCCNC software which is also getting good feedback. All the same, I'm pretty happy with what I have.
But there are as many opinions in this area as there are CNC builders, so take all my comments as one man's view!
Thanks for all the info.
Looking at the steppers on Zapp, http://www.zappautomation.co.uk/elec...ription_tabbed
These ones are (what I believe) you are talking about?
Parallel with 3.2 inductance and 3Nm holding torque at 4.2A.
Can I ask what power solution you are using to get 68v?
I took a look at those controllers but they are way out of my price range.
Currently the steppers and drivers are costing me £300.
With the added power draw this is another big wedge and means ill have to forfeit the controller with the £30 one off eBay.
I get that it is better to spend more on a CNC router but at a point it starts to run over budget :p
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
I'm guessing something like this http://www.zappautomation.co.uk/elec...er-supply.html
Yeah these things can snowball, one more expensive item leads to another and so on... reality is most of us are working to a budget so you need to figure out what you are willing to spend and what will be sufficient for your needs.
If budget is starting to pinch, I would also take a look at what areas it's best to put your money into initially. Might be an idea to go for the better controller (e.g. the CSMIO IP/M mentioned above) and just make do with the cheaper steppers until you feel the need to upgrade.
Ultimately of course you end up spending more by buying cheap then replacing, but reality is it gets you up and running in the mean time.
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Quote:
Originally Posted by
JOGARA
That is the thing. I am not expecting more than 100. Probably not even 50. But at least 25 to make it worth doing the production run.
I have always wanted a CNC table/mill. I want to do a few personal wood projects and some 5-10mm aluminium plate and I think now is a good time to get one.
That rail is a concern. There have been a few videos demonstration this but for what I am doing I don't think it will be that bad?
Most said it was okay though larger jobs it started to cause problems.
I really do like the idea of putting a kit together rather than buying a premade one.
http://www.ebay.co.uk/itm/EU-Stock-4...QAAOSwDFNWFJQE
This one looks the the standard 6040 and is around ~£1,500
But I could put together this kit together for around £1,200. But I get the upgraded 2.2kW spindle, controller and beefer steppers.
Base - £650 -
https://www.aliexpress.com/item/6040...308.0.0.4cDNN7
2.2kW spindle/driver - £200 -
http://www.ebay.co.uk/itm/252593036650
Steppers - ~£230 -
https://www.aliexpress.com/store/pro...612.0.0.NtqLm6
Stepper mounts - ~£15 - Trying to find some EU stock. Only China atm :/
https://www.aliexpress.com/item/3Pcs...999.268.f7AXAm
Cables, Water pump, Tube, cable bendy thing etc - ~75-100
Sounds like a better deal to me...
I would really just avoid those unsupported gantries like the plague... yes they may be ok with plastics and wood but they still limit how fast you can push it and will limit you in the future as well if you look to do some harder materials. It is not an area to cut costs imo as it's extremely difficult to upgrade or improve it later without just buying a new machine (which is what I ended up doing).
What is your time scale? I'm probably building myself a new bigger CNC over the next couple of months and the barebones X6-2200L mechanics would be up for grabs once I've done the machining I need to do for you to go to town on with your own electronics. That's like your generic 6040 but with proper profile HG20 type linear rails.
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Quote:
Originally Posted by
Zeeflyboy
I'm guessing something like this
http://www.zappautomation.co.uk/elec...er-supply.html
Yeah these things can snowball, one more expensive item leads to another and so on... reality is most of us are working to a budget so you need to figure out what you are willing to spend and what will be sufficient for your needs.
If budget is starting to pinch, I would also take a look at what areas it's best to put your money into initially. Might be an idea to go for the better controller (e.g. the CSMIO IP/M mentioned above) and just make do with the cheaper steppers until you feel the need to upgrade.
Ultimately of course you end up spending more by buying cheap then replacing, but reality is it gets you up and running in the mean time.
Yea, I am thinking around £1,500 max.
Probably will go for these switching power supplies at first and upgrade later to the better power.
Would allow me to then have the nice steppers and drivers.
But I would also be using the cheap Chinese controller.
That will probably get me started for now. If I then need to upgrade in a few months at least I have done this project and hopefully have another one where I can spend a few more quid on nicer things if they are needed.
Quote:
Originally Posted by
Zeeflyboy
I would really just avoid those unsupported gantries like the plague... yes they may be ok with plastics and wood but they still limit how fast you can push it and will limit you in the future as well if you look to do some harder materials. It is not an area to cut costs imo as it's extremely difficult to upgrade or improve it later without just buying a new machine (which is what I ended up doing).
What is your time scale? I'm probably building myself a new bigger CNC over the next couple of months and the barebones X6-2200L mechanics would be up for grabs once I've done the machining I need to do for you to go to town on with your own electronics. That's like your generic 6040 but with proper profile HG20 type linear rails.
Looking at the parts on the one I listed; https://www.aliexpress.com/item/6040...999.277.umjtYe
Isn't the Y rail supported underneath?
I know it is not linear rails but should be better than the rods just floating?
The X axis ones are floating by the looks of it.
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Quote:
Can I ask what power solution you are using to get 68v?
A toroidal transformer 24-0-24v in series with one rectifier and two caps
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Quote:
Originally Posted by
Clive S
A toroidal transformer 24-0-24v in series with one rectifier and two caps
Actually, I'm using a 2x45V toroidal with both windings strapped in parallel to give a single 650W supply. Same thing, really!
My first router used LinuxCNC (cheap - nothing cheaper, in fact) and a parallel port to a cheap breakout board. No spindle (speed or start/stop) control. Old analogue drivers. It worked. Not ideal in many ways, but you don't always need "the best". But you do need something that works for you, and it does need to be reasonably reliable. Best thing, I guess, is to try to understand what compromises you are making by going cheaper and deciding if you can accept that for the time being. The other thing to keep in mind is, "Can I easily upgrade it later?" For example, changing a motion controller or stepper drivers is not too invasive. But changing ballscrews for leadscrews, or supported rails for profile rails, might be more difficult later.
I have probable spent around £2500 on my steel-framed, ballscrewed, profile railed, motion-controlled, 1500x750 router. That's probably typical.
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Would something like one of this work?
http://www.airlinktransformers.com/c...Filter+Results
They have 70+70V so would mean 2 sets of 70V?
From what I know, you can connect these in parallel though you have to be careful to get the phases the correct way round?
As for the rating, thinking 2000VA?
As for caps, 110v and as big as i'd like?
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Quote:
Originally Posted by
JOGARA
Would something like one of this work?
http://www.airlinktransformers.com/c...Filter+Results
They have 70+70V so would mean 2 sets of 70V?
From what I know, you can connect these in parallel though you have to be careful to get the phases the correct way round?
As for the rating, thinking 2000VA?
As for caps, 110v and as big as i'd like?
Ok what DC voltage to you want to end up with. What steppers are you using and how many.
Read #31 again 650VA should be more than enough try and get caps that are 100V
http://www.airlinktransformers.com/c...Filter+Results
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Quote:
Originally Posted by
Clive S
Going off what people said, higher voltage the better? So close to the max of the drivers.
As for the drivers, http://www.zappautomation.co.uk/elec...ion/em806.html (buying direct from manufacturer in China)
Steppers, http://www.zappautomation.co.uk/elec...ion/em806.html
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Quote:
Originally Posted by
JOGARA
Going off what people said, higher voltage the better? So close to the max of the drivers.
...which is what you will get if you use a lower voltage transformer. Yes, I know it doesn't sound right, but in practice a 45V or so transformer will end up giving you around 68V DC across the smoothing capacitor(s). This also gives a bit of allowance for the fact that the mains input voltage will vary, and the transformer will probably give you about 5% over the rated voltage under light load to allow for a drop when on full load.
EM806 are good drivers.
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Quote:
Originally Posted by
JOGARA
Those are 80V drives so run them at about 68V to allow for the back emf. 24-24 v in series = 48 = about 68V dc when rectified.
AM882 drives would be less dosh and just as good.
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Quote:
Originally Posted by
Clive S
Those are 80V drives so run them at about 68V to allow for the back emf. 24-24 v in series = 48 = about 68V dc when rectified.
AM882 drives would be less dosh and just as good.
Ohhh
I thought it was 1:1 from transform through rectification.
That makes sense why so many are doing 24-24v.
These are the drivers I am getting https://www.aliexpress.com/store/pro...615.0.0.9rnD8Q
Forgot I changed to them.
Am I right in saying that when the steppers start up or change direction, they require a lot of amps, but when they are going it is pretty low.
Which is why you are able to get away with lower wattage transformers?
Thanks
-
Re: Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet
Quote:
Am I right in saying that when the steppers start up or change direction, they require a lot of amps, but when they are going it is pretty low.
Which is why you are able to get away with lower wattage transformers?
A 625 va trans former will be fine good choice on the AM882