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  1. #11
    Just out of interest you don't state what version of mach you bought... If mach4 you need to be sure whatever motion controller you use will actually work with it.

    General Basic principles of the electronics are similar to 3D printer, but obviously beefed up due to the higher power requirements. Power supplies tend to be higher voltage (at least 48v) and motors have their own dedicated stand alone drivers. Due to VFD noise one needs to be a little stricter regarding good earthing practises. Most 3D printers are also stand alone, most CNC's require a computer running something like mach/ucnc etc so considerations about Ethernet/USB/parallel port and the various advantages and disadvantages of each need to be considered.
    Last edited by Zeeflyboy; 06-10-2017 at 04:39 PM.

  2. Sorry I hadn't appreciated there was more than one version, everywhere I read it stated Mach3, so that was what I looked for.

    Does anyone know of some plans that I can follow and save making an expensive mistake

    Thank you

  3. Well, the more I read, the greater my confusion gets.

    Is there anyone / where near Cambridge or surrounding area that I can see a CNC and ask questions?

    Ideas Please
    Last edited by cambridge_cnc_stuart; 06-10-2017 at 11:52 PM.

  4. #14
    Quote Originally Posted by cambridge_cnc_stuart View Post
    Thank you Guys for your replies and information. I am getting an idea on what I should and shouldn't do.

    How does this sound? I will make the frame from aluminium extrusion of say 30mmx60mm long sides y-axis and 30mmx30mm X-axis. I'm thinking of using two 23nema Steppers on the y-axis unless this is overkill for the length. A 23nema on the X-axis and a 17nema on the Z-axis
    It does not sound good at all to my ears. 30x60 and 30x30 is for 3D printers, not for a CNC. Rigidity and mass are important even if you give up on milling CF. My machine is mainly built using 45x90 extrusions and is definitely not overkill, not even for plastics which I mainly use it for. Wood is not different. I am also milling aluminium but would not start milling CF with it, I think that would be too painful. You should not use any NEMA17, again, they are good for 3D printers or other things where forces are considerably less. Even the Z requires a lot of force and pretty high mass to move up and down at a fast speed, so don't go for a weak solution. There is no advantage in using a small motor, the price difference is negligible.

    Quote Originally Posted by cambridge_cnc_stuart View Post
    I am leaning more towards a moving gantry design. What is the best design / way to allowing the gantry to move.?
    A Spindal of around 2.3kw That's as far as I have gotten so far.
    Good luck. That's what most people chose because it is the sexiest design. The only advantage it has over a fixed beam type is that it looks more impressive when you show it to your friends and that it takes a bit less space. Fixed beam is easier to build, easier to square and align in every angle, AND provides better rigidity. A 2.2kW spindle is pretty heavy, even the 1.5kW I am using is too heavy for NEMA17.

    Quote Originally Posted by cambridge_cnc_stuart View Post
    A few questions now that I wonder about!

    1, Do CNC routers use similar electronics to a 3D Printer?
    2, Do the need microswitches for end stops?
    3, I see a lot of electronics in boxes with fans?? Do they produce that much heat?

    Any opinions/ advice greatfully received

    Thanks once again
    To answer your three questions:

    1. Yes, the electronics in principle the same, but a CNC requires much more powerful motors and better drivers. Also, the 3D printers I looked at, are not driven directly from any software, you generate an STL file and transfer that to the printer using a memory card or some other means and print that specific file. A CNC uses a PC which generates G-code and sends that code to the motion controller. The software can be Mach3, Mach4, UCCNC and so on, some are more expensive than others, but they all communicate with the CNC using the parallel port or through a motion controller using USB or Ethernet, like the UC300USB or UC300ETH or others. Those motion controllers require a driver utility, a plugin, which the software you are using uses to communicate with them. As an example, all the UCx00 from CNC Drive have a Mach3 plugin but no Mach4 plugin. Of course, all can be used with the UCCNC software, since it is made by the same company.

    2. Yes. It is a very bad idea to leave those out from the design because they are actually protecting your machine. I don't think there is anyone on this earth who never hit the limit switches. My machine runs at 9000mm/min and smashing into the sides at full speed is a pretty nasty thing. Even with limit switches it means a sudden stop and a loud bang, so it is scary, but it saves the machine from committing suicide.

    3. Yes and no. The heat depends on your drivers. Some drivers get very hot, others not at all. My drivers are never hot and I don't have a fan in my electronics box. I do have a large fan spinning at low RPM in my PSU box and that fan is temperature controlled, the sensor is on the rectifier. At normal temperature the fan can't be heard, at 35 degree Celsius the rpm is increased to 60% and then gradually if the temperature continues to rise. I don't think I ever had the fan at 100% rpm. The VFD has a fan as well, and that is also spinning at low RPM unless the heat is increased. I have never had the fan at 100%, so that is also pretty quiet. Steppers can get hot, up to 60 degrees, but that's normal. I have no cooling on those. Note that I have all those in three separate pretty large boxes. The VFD has it's own, delivered by the factory, but the PSU and the electronics is my own design, so those use the boxes of my choice. Many people build everything in a smallish box, which I think is a bad idea, but it is up to each to decide what they prefer. In those cases there is probably a need for fans because the air inside will be heated and the lack of natural air flow is prevented, so you must have a fan (at least one) to generate air flow and cool the contents. Also many people use cheap Chinese switching PSUs and all those have a small fan which is spinning all the time, generating high noise. Also, if you have a powerful machine you may need individual PSUs for each stepper, generating even more noise. So, in short, there are always fans involved somewhere, but the number of them and how much noise they generate depends on the design.

    A CNC is much more complicated than a 3D printer, so don't underestimate the challenge you are facing. While a 3D printer works in principal the same way, I don't think they are actually comparable in any other way than both apply synchronized axis motion on 3 axes.

  5. #15
    Quote Originally Posted by cambridge_cnc_stuart View Post
    Sorry I hadn't appreciated there was more than one version, everywhere I read it stated Mach3, so that was what I looked for.

    Does anyone know of some plans that I can follow and save making an expensive mistake

    Thank you
    Perhaps you can find some free of charge, but I think it may be difficult. Also, DIY means that you WILL make mistakes, so that should be added to the budget.

    Here is a link to a current build log:

    http://www.mycncuk.com/threads/11266-3-Axis-900x500mm

    The machine is about the same size you are planning for. Maybe he is ready to help you out, and maybe you can take a trip to him and have a look... Even if he is not in Cambridge, in your case I think it is worth to take a trip even if it might need a night in a hotel or B&B. He can definitely give you an idea about a realistic budget.
    Last edited by A_Camera; 07-10-2017 at 02:24 PM.

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  7. Quote Originally Posted by A_Camera View Post
    Perhaps you can find some free of charge, but I think it may be difficult. Also, DIY means that you WILL make mistakes, so that should be added to the budget.

    Here is a link to a current build log:

    http://www.mycncuk.com/threads/11266-3-Axis-900x500mm

    The machine is about the same size you are planning for. Maybe he is ready to help you out, and maybe you can take a trip to him and have a look... Even if he is not in Cambridge, in your case I think it is worth to take a trip even if it might need a night in a hotel or B&B. He can definitely give you an idea about a realistic budget.
    Thank you A_Camera for taking the time to send me an in depth reply, it really is appreciated. I'm quickly believing I am out of my depth. Drowning in my innocence. I was quite confident to begin with, but that as now evaporated.

    Having spent many hours watching videos, reading builds, searching the Internet. I am now totally lost, confused and despondent.

    Back to the drawing board.

    Thank you once again
    Last edited by cambridge_cnc_stuart; 07-10-2017 at 03:02 PM.

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  9. Clarification, all my 3D Printers have the option of printing from GCODE but I use them connected directly to a laptop or Desktop PC and can make changes on the fly. I have never used the SD card approach. The software I use if Simplify3d or Repetier Host.

    Respect

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  11. #18
    There is no need to spend more hours watching videos. Here on this forum 99% of the builds are exemplary plus the guys earlier have pointed you to all the details.

    Just to resume:
    nema23 3nm motors on all axis driven by AM822 at 70VDc
    1610 ball screws on all axis, 1605 on the Z, pulleys HDT5 15mm wide 20t from motor to ball screw
    2.2kw spindle is the typical compromise between power money and ability to cope with tasks
    20 size square rails Hiwin or chinese copy, don't use open builds or v rollers or skate rollers or other crap.
    buy all hardware from BST Automation Aliexpress or other reputable seller.
    Either use the recommended aluminum profile or make a structure from 80x80x3 or 100x100x3 box section.

    Just read the builds in forum, all is there detailed and with pictures. i don't know what is with all to imagine that they are engineers and design every single machine from scratch. Just copy a well known and successful build and spend your time using the machine, instead of designing it. if you are into welding use my first build as inspiration and there are free plans in Sketchup. If you are into aluminum even better, many good builds.

    You will need proper motion controller, not 3d printing solutions. Ethernet is what people use nowadays, not USB. CSMIO and Mach3, offline DDCSV1, UCCNC controller and software and so on.

    Also you will need a seriously big enclosure, Power supply ets.

    Once you start the build thread people will help you there so all will progress fast. But at the end of the day you will need to read some build logs,. Without that it will be too long to explain all. And dont read logs from the Zone as you will get too much useless information in your head.
    project 1 , 2, Dust Shoe ...

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  13. #19
    Very good post Boyan Have a look a joe's log http://www.mycncuk.com/threads/4755-...-head%21%21%21 all done without special tools
    ..Clive
    The more you know, The better you know, How little you know

  14. The Following User Says Thank You to Clive S For This Useful Post:


  15. #20
    Quote Originally Posted by Clive S View Post
    Very good post Boyan Have a look a joe's log http://www.mycncuk.com/threads/4755-...-head%21%21%21 all done without special tools
    Also some finished machines here:
    http://www.mycncuk.com/threads/10066...s-picture-menu
    Building a CNC machine to make a better one since 2010 . . .
    MK1 (1st photo), MK2, MK3, MK4

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