Re: 1st Build, will this be a decent Design?
You have gotten a lot of good advice here but the one point that has to be stressed is that you need to know and understand how your expectations impact the machines design!!! It isn't enough to say it is a hobby machine. The best way to avoid grief thatbuilding the wrong machine causes is to think long and hard about what you want the machine to do. Then educate yourself about what is required to get there.
Being hobby or DIY, often the real challenge is balancing a budget against what is required to get the results you want.
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Originally Posted by
BigFellaPhil
Hi Olf, I didn't check the manual, no, just what I've read on here and I've seen a few YouTube videos, but I will check it now thanks for the info...
Peet - I like a challenge and although the BuildBotics looks great,
When it comes to electronics there are many suppliers, some of which are hard to find on the web. You have the likes of PMDX on one end and Centroid on the other. There are many vendors competing with these guys.
If your electrical / electronics build abilities are weak, or for that matter time is a problem, I’d suggest buying hardware that is either a complete product or at least a partially built subsystem. The PMDX 340 is an example of a box that greatly reduces wiring effort. The problem here is that it is likely too small (driver capacity wise) for a CNC of your size. Do consider similar solutions from other vendors like Gecko. I’m suggesting these sorts of prefab solutions because you don’t appear to be ready to do a CNC controller build at a high level of detail. You still need to do a DIY controller but your effort is minimized.
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I had really wanted to learn a bit more about the Electronics side of CNC as that's what I know least about so using this would take the challenge away somewhat.
Well this is where you need to decide if you want to build a CNC or learn the electronics. Both are possible but do realize that learning the electronics side of the tech will take time. If you want to learn about the electronics side of things it would be far cheaper to buy an Arduino, a shield and steppers and drives. If you really want to learn the electronics I’d suggest that it makes sense to spend some time with an Arduino and learn about the electronics there. There are a couple of reasons beyond cost too. For one the whole point of the Arduino is to educate people with respect to embedded electronics and software. It is a good learning platform. Another reason is the breadth of knowledge you can obtain that will make understanding CNC electronics easier.
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Cheers again Ger, for your help.
I find myself agreeing with Ger most of the time he offers good advice.
This post though has me wondering which is the higher priority here, learning electronics or building the CNC? In the end either is a worthwhile pursuit I’m just not sure learning the electronics while building a CNC makes sense. At least not the basic concepts that drive the electronics world. There is enough stuff online that you can cover basic electronics in a month or two of study and experimentation. Look for the old Navy training manuals for electronic techs. That series combined with the Arduino info online can really beef up your electronics knowledge.
Re: 1st Build, will this be a decent Design?
Hi Wizard, the main Priority is definitely the CNC Machine, I love learning, so if I can also learn other skills whilst doing something else then that's a double bonus!
I've decided on the UCCNC route so my understanding from the info on here, I need 2 x DC Power Supplies (one 5v and one 24v) and do I also need another Power Supply for the motors, does anyone have recommendations or would any Power Supply work fine? I've got my Stepper Drivers (RTELLIGENT R86) and all my 5 core + Earth CY Cable. I'm thinking of an AXBB-E Controler - what BOB would be best are they all relatively the same... I wanted a water-cooled Spindle as i've heard theses are quieter than air-cooled ones is there a specific VFD for water-cooled spindles or are they all the same..?
Re: 1st Build, will this be a decent Design?
The AXBB-E does not require a breakout board, unless you need to use it's expansion port.
Yes, you need a power supply for the motors. What are the specs of the motors and drives? The higher the voltage, the better the performance.
The VFD is sized to the spindle motor. There's no difference between an air or water cooled spindle as far as the VFD goes. Most people buy a kit with both spindle and VFD.
Re: 1st Build, will this be a decent Design?
A quick look at the product page indicates that the AXBB-E has enough I/O for your machine by itself; I doubt that you will need to make use of it's expansion port. Although I personally have no experience with it; the product page looks OK; and I will trust Gerry that it's good stuff. :)
So... just FYI... yes, breakout boards do vary extensively; some are literally just a DB25 connector and some screw terminals on a PCB, with no electronic components on them whatsoever. All they do is bridge from the DB25 cable to your discreet wiring. Others have buffer chips, opto-isolators, op-amps & integrators, and/or power transistor drivers on them as well as the DB25 and screw terminals. Quality and documentation vary as well; I was just looking at one for $5 on Aliexpress; there was no setup information that I could find for it; and if it breaks, well... you will probably have to buy a new one (on the other hand... it's five bucks; so I guess I'd probably buy several ahead of time, were I to choose those).
And then there's the integrated solutions like the AXBB-E which contain both the motion control engine as well as the breakout board functionality with buffers, opto-isolators, power transistors, and signal conditioning electronics; one-stop-shopping, as it were.
:)
Re: 1st Build, will this be a decent Design?
Morning Ger - The drives are - 2.4a-7.2a, 24-100vdc and the Motors are - 5.6a (Bipolar Parallel) 400oz/inc 24-48v, 8 wire Nema23's
Thanks for the info Britt, The AXBB-E sounds like the one for me then, I'll crack on and get it ordered! :)
Re: 1st Build, will this be a decent Design?
I'd use a minimum 48V power supply, or even a 60V supply. For four of those motors, I'd get a 15amp supply. Something like this.
PS-10N56 - 1000W 56V Power Supply - AnTek Products Corp
Re: 1st Build, will this be a decent Design?
Thanks for the link, I know you generally get what you pay for but I've seen this and wondered if it would be suitable/worth it - https://www.amazon.co.uk/MEISHILE-22...6MKF5WW3X&th=1 - it's £90 cheaper and has more Volts and Watts so thought it could do the job, what are your thoughts??
Cheers,
Phil
Re: 1st Build, will this be a decent Design?
That's a Chinese switching power supply... generally less reliable than the Antek. The Antek is a much simpler design; to the point that it's end-user repairable if anything other than the transformer itself gets damaged.
I'd pick the Antek; for two reasons.
First; I doubt that you will have a major problem with it necessitating a replacement; but if something goes wrong with the Chinese unit you will probably need to buy a whole new unit. Antek is a US company with a good reputation.
Second, switch mode power supplies can fail in a manner that puts high voltage on the outputs; although possible with a transformer based unit like the Antek, it's less likely (this would involve a breakdown of several layers on insulation - transformers usually fail because the one of coils went open).
:)
Re: 1st Build, will this be a decent Design?
When powering stepper drives simple power supplies are OFTEN better but not always. The reality is you just need a transformer, rectifier and filter cap for most drivers. Just make sure the supplies output voltage is below the drivers max voltage by a good deal, considering your local conditions.
You can buy switch mode power supplies that will power stepper drivers but they need to be designed to work in an environment with motors. The problem with SMPS is that many have current limit or over voltage protection that can interact with the driver/motors in weird ways. This especially if the motor puts an excessively high voltage on the bus. So if you are going to buy a switch mode supply for powering motor drives you have to make sure the supply is designed to work properly in that situation.
The Antek mentioned shouldn’t have any problems at all.
Re: 1st Build, will this be a decent Design?
A lot of drives do NOT like SMPSs, for a very good reason. The remaining high frequency noise on the supply can send the driver mad. That is the main reason you are recommended to use a very simple transformer/diode/capacitor PS for the motors.
Cheers
Roger
Re: 1st Build, will this be a decent Design?
Great advice again everyone, thanks very much for the info, I will get the PS mentioned by Ger, it sounds like a good choice.
Re: 1st Build, will this be a decent Design?
You can put in a diode and a buffer capacitor. That is how the SMPSs are connected in my machines. The diode protects the PSU from the spikes and the capacitor buffers the voltage. And you can parallel the SMPSs this way, one diode per PSU and common buffer capacitor.
The diode can be one diode connected in a bridge rectifier, those are cheap and can work with high currents.