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Thread: CNC Optimum DM45 Milling Machine - Need advice

  1. #21
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    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    Some of the hardware Linuxcnc can manage include simple parallel port breakout boards, a range of solutions from Mesa, Pico systems and General Mechatronics as well as ethercat systems. The Mesa ecosystem is particularly interesting as it can be extended to an almost infinite number of motors, encoders and Input and output cards. With a parallel port, linuxcnc generates the step pulses but with Mesa the stepgens are on the hardware board. Linuxcnc tells the stepgen to run art a given frequency which it does until told otherwise. But LinuxCNC can change that commanded frequency 1000 times a second! I use stepper motors and settled on a Mesa 7i76e ethernet card which has 5 step gens, spindle encoder 2 MPG inputs for jog wheels, 32 inputs, 16 outputs, a smart serial RS422 interface for additional IO plus 2 x 25 pinconnectors that can add two more cards so a 7i76e and 2 x 7i76 cards would give you 15 stepgens and over 100 inputs......
    Good day rodw,
    Can you show me a link or an example of full Linux cnc wiring diagram consist of such as motion controller, BOB, stepper/servo driver, linux boards, etc. ? So I can see clearly. I read a lot of your explanation, it looks like interesting ...

    - - - Updated - - -



  2. #22
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    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    Quote Originally Posted by asuratman View Post
    Good day rodw,
    Can you show me a link or an example of full Linux cnc wiring diagram consist of such as motion controller, BOB, stepper/servo driver, linux boards, etc. ? So I can see clearly. I read a lot of your explanation, it looks like interesting ...

    - - - Updated - - -
    I've never been one for wiring diagrams, I just built a table of the pins as I connected them which is a few pages now. See the attached screen dump.

    But Norbert on the Linuxcnc forum shared a connection sheet for the Mesa 7i76e which I am sure you will find pretty amazing if you are used to the limited pins on a ESS board. PDF file is attached. Norbert is the author of the gmoccappy touch screen GUI for Linuxcnc which I use.

    Take the time to study how many different types of hardware that can be connected. as well as the additional expansion builtin.

    Attached Thumbnails Attached Thumbnails CNC Optimum DM45 Milling Machine - Need advice-screenshot-2019-07-08-9-04-17-a  
    Attached Files Attached Files
    Rod Webster
    www.vmn.com.au


  3. #23

    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    Hi Guys, just wondering which of these if any would be ideal for the mill conversion. Your opinion matters. I've had a few sellers contact me today. These two seem to have good feedback and they were priced well.

    https://www.alibaba.com/product-deta...fb5e3e5fRd0ht1

    https://www.alibaba.com/product-deta...fb5e3e5frt2qbb



  4. #24
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    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    I agree with Rod, instead of saying and with No experience in CNC your going to "design" your own machine. Then ask a million questions you need to learn about CNC (perhaps a book or two) and study the equipment already on the market or at least successfully built.

    1000x750 Workbee CNC - Mach4 - PMDX USB - Windows 10 Pro


  5. #25

    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    Hi George, I don't recall saying I was going to "design" my own CNC machine. I thought this forum was about getting advice and help from people who have gone through this with their own machines. I must have joined the wrong forum. As a matter of fact, I've watched a lot of videos and have read a lot of forums. Unfortunately, the electrical side is the one side I don't understand and the reason I'm asking questions. I haven't asked any questions about the mechanical side, because I know what I have to do there. If by asking questions about something I don't understand makes me out to be a pain in the ass, I'm wasting my time here. What are you referring to about Rod? Agree with what? He didn't say anything to me



  6. #26
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    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    You said: I'm in the process of building my first CNC mill. Rods advice : Take the time to study how many different types of hardware that can be connected. as well as the additional expansion builtin. I agreed with Rod, take time to learn.

    1000x750 Workbee CNC - Mach4 - PMDX USB - Windows 10 Pro


  7. #27

    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    I thought part of the process of learning was to ask question about things you're not sure of? I must of misunderstood that. I came on here to learn about the process of CNC. I don't need any advice on things I'm already aware of. I won't waste anymore of the forums time. If you're gonna make comments, you might wanna keep other people's names out of it. It suggests they're making arrogant comments too. And yes, your comment was arrogant. It's pretty sad that you feel the need to put people down for asking questions about things they don't understand, you must have a sad life. I'm done.



  8. #28
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    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    Quote Originally Posted by Bob_ski View Post
    Hey Bob,

    Just wondering how you setup your limit switches? I couldn't open the pics.
    Limit switches. Oh fun. Actually mine are setup very simply. For the X axis I used the existing stops that are on the front of the table to trigger a mechanical switch. It replaced the existing center stop that is mounted to the saddle with a bracket that holds the mechanical switch. Then I put a 3D printed plastic cover over the switch to keep the chips out. The other Y and Z are done the same way except there was no existing stop, I had to fabricate them.

    If I had it to do again, I would use capacitive proximity sensors instead of mechanical switches. But the mechanical one's work just fine when you keep the chips out of them.

    X Axis limit switch.
    CNC Optimum DM45 Milling Machine - Need advice-2019-07-08-11-09-11-jpg

    X Axis limit switch with the cover off.
    CNC Optimum DM45 Milling Machine - Need advice-2019-07-08-11-10-51-jpg

    Y Axis. Way down under the table.
    CNC Optimum DM45 Milling Machine - Need advice-2019-07-08-11-11-08-jpg

    Z Axis on the side of the column/head.
    CNC Optimum DM45 Milling Machine - Need advice-2019-07-08-11-11-49-jpg

    Here is the detail of the X Axis switch cover.
    CNC Optimum DM45 Milling Machine - Need advice-2019-07-08-11-12-47-jpg

    Attached Thumbnails Attached Thumbnails CNC Optimum DM45 Milling Machine - Need advice-2019-07-08-11-12-47-jpg   CNC Optimum DM45 Milling Machine - Need advice-2019-07-08-11-09-11-jpg   CNC Optimum DM45 Milling Machine - Need advice-2019-07-08-11-10-51-jpg   CNC Optimum DM45 Milling Machine - Need advice-2019-07-08-11-11-08-jpg  

    CNC Optimum DM45 Milling Machine - Need advice-2019-07-08-11-11-49-jpg   CNC Optimum DM45 Milling Machine - Need advice-2019-07-08-11-11-49-jpg  


  9. #29
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    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    I am sorry Bob, I might of over reacted to your question. But we get So Many new folks on here, that have never before seen a CNC machine but are going to Design one??? They ask a million questions and when the answers come they do not understand what was posted.

    As far as LinuxCNC a lot of folks are using it. I have Mach4 and I love it, but I will never have a Windows 10 computer running in my shop. All mine is on Windows7 Pro.

    1000x750 Workbee CNC - Mach4 - PMDX USB - Windows 10 Pro


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    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    On the subject of limit switches, Lets look at proximity switches. I came up with the following activator for proximity switches

    With Linuxcnc requires the home switch to remain triggered until the machine reaches the limits so it knows which side of the limit switch trigger it is on when powered up. and it needs time to coast to a stop for accuracy.
    So I use two proximity sensors one for home and one for min limit mounted at different heights.

    One significant advantage of my Mesa hardware is there are plenty of inputs so there is no need to share inputs (which is still supported by linuxcnc) So I use seperate min limit, max limit and home switches everywhere (except on the Z axis max limit due to space considerations). Thats a total of 11 inputs. All Prox sensors are PNP to suit the Mesa 7i76e. In this pic, (on the moving gantry) the third sensor on the right is for the max limit striker. Note that if the machine was powered up in this position, the home switch is triggered so Linuxcnc knows to move to the right until the home sensor is no longer triggered before commencing the homing sequence. The other advantage of seperate home and limit switches is that I can home the machine to its current position. With shared home/limits this would not be possible as when the machine come sout of homing, a limit switch is actiated and it would fault. SO with shared switches you would need to move the blue sensor off the sensing plate to the right and loose a lot of travel (unless you substantially slowed the homing velocity to limit the overtravel when coasting.

    In my design, all my wiring is contained on the gantry so it can be removed and there is no wiring on the table.

    I have to say there were many hours of thinking and experimentation to get to my design.

    So now you have it, choose a platform, get your motors and a interface card and build something!

    Rod Webster
    www.vmn.com.au


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    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    Rod, On my Mach4 machine, a 4x4ft router I only use 4 proximity switches total to do the Homing and the Limits. Mach treats the switches as Homing until that routine is done.

    Nice job on 3D printing the limit switch covers!

    1000x750 Workbee CNC - Mach4 - PMDX USB - Windows 10 Pro


  12. #32

    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    Thanks George. It's all good, no hard feelings mate. I can understand where you're coming from now. I joined this forum a couple of months ago, but wasn't going to post anything until I started the build, and could share my build. Unfortunately receiving dodgy motors prompted me to ask about their integrity. I really appreciated you comment of contacting Ebay and opening a dispute. I did that, so now I am waiting for for the seller to organise shipping back to them. This has now put me back at square one where I am searching for motors again, but won't be buying them through Ebay again.

    I purchased my mill last week and paid 3k for it. It's sitting in my workshop in pieces. Most of my friends would think I have lost my marbles paying so much for a machine and then pulling it apart. I'm dedicating all of my free time in building this machine. To a point where I finish my work at about 6pm and then jump on the computer researching what others are doing with their machines. We're all learning new things everyday and it's amazing that you think of a way of doing something, and then seeing what the other person has done and thinking, wow, that is so much simpler and very effective. My method of building something is to over engineer it. It's probably better to be over engineered than under, but also puts unnecessary time on the job.

    My old PC that i'll be using is a Windows 7 Pro, so it's good to know that it will be suitable for the CNC. These are the sort of things I'm learning everyday, and I didn't have to ask the question.



  13. #33

    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    Hi Bob, thanks for taking the time to post the pics, much appreciated. It's simple but very effective and does the job. Also easy to get to if they need to be replaced.

    I have noticed that a few people are using NPN inductive proximity sensors on builds. I like the idea of them but wouldn't purchase something like that from Ebay and risk having the machine crash from using cheap quality sensors. I have looked at some decent quality ones at about 40 bucks a pop. Well worth the money in protecting my machine from failure. I like the idea of the mechanical switches too, less that can go wrong with them. Just have to protect them from crap getting into them. Great job with the covers. I bet they do the job well. I've also been contemplating using both mechanical and inductive. Too overkill? I'm thinking that If one fails, you have the other as back up. Thanks again for taking the time to post the pics and info.



  14. #34

    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    Hi Rod, thanks for the info and the pics. What is the likelihood of the machine losing the plot and going past it's limits and crashing by only using a homing switch? I was contemplating doing the same thing you've done, except I was only thinking of using 2 switches. I was wondering how it would do the homing. You've cleared that up by having a third switch. Definitely need to do more research when at this stage.

    I'm probably getting a little carried away and getting too far ahead of myself. I'm only at the stage of making and assembling the parts to make the machine move. I need to concentrate on that at the moment, it's getting to overwhelming thinking too far ahead about things I don't understand properly yet. As I get through stages, I'll be doing my homework on that particular thing and having a better understanding of it. I'm sure once I get through the build, I'll have a better understanding of the whole thing.

    I appreciate all of your input, it clearly shows you have a lot of knowledge on this. I hope I get to that point one day. I'm really glad you have shared this with me. I'm sure I'm going to read back at this and the info is going to come in handy.

    I'll start posting pics soon on the build and share my journey through it.



  15. #35
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    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    Quote Originally Posted by Bob_ski View Post
    Hi Bob, thanks for taking the time to post the pics, much appreciated. It's simple but very effective and does the job. Also easy to get to if they need to be replaced.

    I have noticed that a few people are using NPN inductive proximity sensors on builds. I like the idea of them but wouldn't purchase something like that from Ebay and risk having the machine crash from using cheap quality sensors. I have looked at some decent quality ones at about 40 bucks a pop. Well worth the money in protecting my machine from failure. I like the idea of the mechanical switches too, less that can go wrong with them. Just have to protect them from crap getting into them. Great job with the covers. I bet they do the job well. I've also been contemplating using both mechanical and inductive. Too overkill? I'm thinking that If one fails, you have the other as back up. Thanks again for taking the time to post the pics and info.
    Like I said I use Mach 4. It uses soft limits. My limit switches on the mill are used only once when the system is turned on. I reference the axis at startup and after that the switches are never used. Soft limits take over. So in that sense, I guess, the limit switch is itself the redundancy. So, i think, redundant hardware is not necessary.

    There are several types of proximity switches. Capacitive switches sense ferrous metals, Hall Effect sensors detect a magnetic field, so with those you have to mount a magnet on the machine. Those are the 2 basic types.


    -Proximity sensors are cheap. Should be less than $10 US.
    -Hall Sensors have a longer detection distance than capacitive one's. The distance is based on strength of the magnetic field they are given. Those tiny pancake magnets usually trigger a sensor at 8-16mm.
    -If you use Hall Sensors, with magnets, beware. Magnets attract iron/steel chips. You want to make sure that your magnets have a cover that keeps them from loading up with chips and causing problems.
    -Hall sensors are a bit smaller than capacitive detectors. Either one can fit in a 8mm package. Some are longer than others.
    -Capacitive sensors can tell the difference between iron/steel and aluminum. Both will trigger the sensor, but the iron/steel will trigger at a greater distance. I use a 5mm pan head screw to trigger my X axis lathe sensors. The top of the screw is about 2mm from the sensor.
    -Both proximity sensors require power. Since they require power, if you don't power the sensor, it wont sense anything. If you use mechanical switches that are normally closed, your system will stop if a cable is disconnected. If the cable comes off the sensor, depending on what sensor you are using, it may not trigger an error.
    -Since the sensors need power, you will have to provide it to every one. usually 6-36 volts 3 wires / sensor instead of 2.
    -I always try to design electronics so that un-fused power is not in a cable. If the cable is cut and the power is shorted, the whole thing goes down. Or if it's an electronically noisy system, the RF noise will couple onto your power supply.

    Mechanical switches definitely have some advantages.

    On my lathe X axis uses capacitive sensors. The sensor is under the red cover. It detects the 2 panhead screws on the aluminum bar as it moves back and fourth.
    CNC Optimum DM45 Milling Machine - Need advice-2019-07-08-22-13-49-jpg

    The Z axis uses Hall Sensors. The sensor is the blue circle on the right, the magnet is in the red plastic thing on the left.

    CNC Optimum DM45 Milling Machine - Need advice-2019-07-08-22-14-36-jpg

    Attached Thumbnails Attached Thumbnails CNC Optimum DM45 Milling Machine - Need advice-2019-07-08-22-13-49-jpg   CNC Optimum DM45 Milling Machine - Need advice-2019-07-08-22-14-36-jpg  
    Last edited by maxspongebob; 07-08-2019 at 11:00 PM.


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    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    Quote Originally Posted by wmgeorge View Post
    File a complaint with eBay and the vender. Since he is in China he will try to stall and delay as long as he can until your Return/Refund time expires.
    Yep, that's their game. But ebay has your back. As long as you file a complaint before the expiration time, they give the seller 2 days to respond. If no response, ebay will refund your $$ and NOT advise you to send the item back. China is great at sending stuff to the US, but woefully incapable of facilitating a return. BTW, per ebay guidelines, the seller is supposed to pay return shipping. I just went through this with a 5 axis controller, and ended up accepting a 50% refund. Had I played it right, I could have gotten a full refund. I made the mistake of filing a complaint with both ebay and Paypal.

    <a href="http://www.cnczone.com/forums/mini-lathe/82871-7-x-10-project-started.html" target="_blank">7X10 Lathe conversion</a>
    <a href="http://www.cnczone.com/forums/open-source-cnc-machine-designs/335846-cnc.html" target="_blank">Custom X-Carve router</a>
    <a href="http://www.linkedin.com/in/tooldesign" target="_blank">LinkedIn</a>


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    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    Quote Originally Posted by wmgeorge View Post
    Rod, On my Mach4 machine, a 4x4ft router I only use 4 proximity switches total to do the Homing and the Limits. Mach treats the switches as Homing until that routine is done.!
    Every platform is different and of course Mach4 normally does not have enough inputs to do what I did. You can set Linuxcnc up that way but on my 4x4 plasma cutter, I decided to make it a complete build and not cut corners. Thats how I thought most commercial machines were set up so thats what I did!

    Quote Originally Posted by Bob_ski View Post
    Hi Rod, thanks for the info and the pics. What is the likelihood of the machine losing the plot and going past it's limits and crashing by only using a homing switch? I was contemplating doing the same thing you've done, except I was only thinking of using 2 switches. I was wondering how it would do the homing. You've cleared that up by having a third switch. Definitely need to do more research when at this stage.
    The main thing to understand is that limit switches should never be triggered becasue they sit outside your soft limits (yes Linuxcnc has them too) and outside the limit switches I have hard limit stops.
    The scenario you mention is not likely becasue with a shared home/limit switch it is a limit switch all the time unless you are homing and then its a homing switch during the homing sequence..

    Rod Webster
    www.vmn.com.au


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    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    Quote Originally Posted by rodw View Post
    Every platform is different and of course Mach4 normally does not have enough inputs to do what I did. You can set Linuxcnc up that way but on my 4x4 plasma cutter, I decided to make it a complete build and not cut corners. Thats how I thought most commercial machines were set up so thats what I did!

    The main thing to understand is that limit switches should never be triggered becasue they sit outside your soft limits (yes Linuxcnc has them too) and outside the limit switches I have hard limit stops.
    The scenario you mention is not likely becasue with a shared home/limit switch it is a limit switch all the time unless you are homing and then its a homing switch during the homing sequence..
    Mach4 can have as many inputs as how many it's motion controller has. For example with this card it has 49 digital and 2 analog inputs: CNCdrive - motion controls



  19. #39

    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    Thanks for the input Bob, all of the info you provided is much appreciated. I will definitely be referring back to all of this information provided. Thank you for taking the time to post.

    I totally agree with you there Blades, it's a game to them. I don't understand why they feel the need to play these games. I purchased the motors from a Chinese seller in Australia. They are a Chinese company with a shipping centre In Sydney. They could have just took it on the chin and replaced the motors with new ones. After all the crap I'm going through to get a refund now, I won't be buying from them again.

    Definitively a lot of learning still to do Rod. I will be doing my research on the specific job I'm doing at the time. I'll be making sure I fully understand what I have to do before I do it. Good to see so many people willing to help you when you need it. I might have said this a couple of times now, but it's really appreciated.



  20. #40
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    Default Re: CNC Optimum DM45 Milling Machine - Need advice

    Quote Originally Posted by OlfCNC View Post
    Mach4 can have as many inputs as how many it's motion controller has. For example with this card it has 49 digital and 2 analog inputs: CNCdrive - motion controls
    That is correct, I use the CNCRP/Avid controller panel with Warp9 ESS. . Mach4 is a huge leap from 3. My machine works just fine using the Limits as a Homing switch, also it just a lot simpler. My proximity switches can never be damaged as the trigger block is totally out of the path. The rubber stops act as a snubber.

    WinCNC is a good program, but I really need a Windows system to run a lot of my programs. Yes I have used Linux in the past so I know about it.

    Last edited by wmgeorge; 07-09-2019 at 08:17 AM.
    1000x750 Workbee CNC - Mach4 - PMDX USB - Windows 10 Pro


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CNC Optimum DM45 Milling Machine - Need advice

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