CNCing a mini mill

Discussion in 'CNC Machines and Conversions' started by d65, Feb 6, 2020.

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  1. Feb 6, 2020 #1

    d65

    d65

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    What are the advantages and disadvantages of cncing a mini mill vs keeping t manual? I look foray to your responses

    d65
     
  2. Feb 6, 2020 #2

    vederstein

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    When I CNC"d my mini it cost more than the mill itself.
     
  3. Feb 6, 2020 #3

    kvom

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    I personally think you still need a manual mill even when you have a CNC mill.
     
  4. Feb 7, 2020 #4

    RM-MN

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    Some people have good hand/eye coordination and find that a manual mill works best for them, especially when doing a "one off" project as CNC takes plenty of time for setup and from then on saves time as it repeats exactly so you get multiple products that are the same. Some of us have difficulty with the hand/eye coordination and make so many mistakes in the milling that we create more scrap than true output. For us the time to make the CNC program and the troubleshooting the output is worth it. You have to decide what your purpose would be for making the mill CNC. In my case it is the combination of the hand/eye coordination and the desire to learn something new and making a mini-mill into a CNC and then learning to design in CAD and then going through the CAM fulfills that desire.
     
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  5. Feb 9, 2020 #5

    d65

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    I’m thing of going manual to start so I can learn basic milling skills. Almost all of my stuff willl be one off.

    D65
     
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  6. Feb 24, 2020 at 7:09 PM #6

    awake

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    D65, if you have not done any machining, there is value in starting out on the manual machines - you will gain a "feel" (literally) for things that way, e.g., how fast you can push things, how deep a cut, etc. Do keep in mind that some of those parameters may be significantly different on a larger machine vs. a smaller machine, but some things will be universal, e.g., RPMs and SFM and such.
     
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  7. Feb 25, 2020 at 5:56 PM #7

    Peter Twissell

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    Plus one re. Learning to use the machine manually first.
    It is quite practical to add ballscrews and servos to a mill and preserve the ability to use it in manual mode.
    Perhaps even better is to add 'virtual' handles, which are just pulse generators triggering the servos. A mill fitted with these is a pleasure to use, allowing climb milling without snatching and a nice smooth feed rate independent of cutting load.
     
  8. Feb 26, 2020 at 2:10 PM #8

    CFLBob

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    I've converted two mills to CNC, a micro mill (Sherline) and a 1 HP Grizzly G0704 mill.

    I have to agree with the idea that learning to make some parts by hand is a good way to start. One reason is that it forces you to think of making straight cuts in X and Y - and coming up with ways to hold the part in a fixture. Holding the parts is critically important. Say you need to cut a part with a tapered side - with CNC you just tell it the start and stop points and it figures how to do it. With manual milling, you need to figure out how to do it in a straight X or Y cut.

    The tradeoff is that if you're going to do a lot of parts manually, manual mills are much easier to use with Digital Read Outs - DROs - I get distracted very easily while counting rotations of the cranks. A good set of DROs will cost close to what it costs to convert to CNC.
     
  9. Feb 26, 2020 at 4:13 PM #9

    timo_gross

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    I do not agree that DROs are so expensive, entry level units cost as much as only a few ruined parts?
    Good DRO-s will cost a lot, yes.

    @d65: How about get started with manual.
    A lot of fantastic tips out there in the Internet, what can be done with clever setups and some additional tooling. ( dividing head, rotary table, dial indicator )
    I have an entry level 2nd hand hobby CNC machine. Often whish(ed) it was just a more heavy manual machine. ( weight / power wins.... )
    With the manual machine all hardware for conversion can be made. Get an idea how often a CNC would solve problems, how often repetitive work is done and how often CNC creates problems.
    ( reading forums and fighting some stupid Software cutting where the part should be and leaving stock where the chips should fly, Computer snapping cutters were a Human operator would slow down )

    Cheap CNC in doubt is not as accurate as a carefully manual operated machine. Backlash, accuracy of Electronics, Electric and Software, feedback system.

    Just thought from another beginner.....

    Greetings
     
    Last edited: Feb 26, 2020 at 5:18 PM
  10. Feb 26, 2020 at 4:40 PM #10

    Peter Twissell

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  11. Feb 26, 2020 at 4:45 PM #11

    Peter Twissell

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    Incidentally, I fitted 3 axis DRO's to my mill for less than £100 total. They are the cheap, magnetic strip type, but the repeatibility is plenty good enough for my application. I still use the handwheel scales for the last couple of thou, but the DRO's are very useful to check that i'm not one full turn out, or have the backlash the wrong way.
     

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