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Fine tuning my machine, please help

Discussion in 'CNC Mills/Routers' started by Elijah Anderson, Sep 19, 2017.

  1. Elijah Anderson

    Elijah Anderson Well-Known
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    Thank you guys for reading this thread, I have a budget build CNC router that I built and before I show the complete build I need to get everything fine tuned and calibrated. This being my first EVER build I have no idea what I am doing.

    So I have a DB25-1205 Break our Board comtrolling my DQ542MA stepper drivers. All of this is being controlled via MACH3.

    So, everything moves, just not in the right increments. So I need someone that has a similar setup, or someone that knows exactly what I need to do to calibrate the machine.

    MACH3 is set for inches, and this is the measurements that I would like to use throughout the system.

    my drivers are set to the proper amperage, and set to 2000 steps
    My MACH3 is also set to 2000 steps, but beyond that I am clueless of where to begin, I use the drivers that you can purchase here, so the DIP settings should be what ever you have on yours, and I use the high torque nema23 motors from this store too, so if anyone has the settings that will work for me, or that can guide me through the process that would be great. This is the last thing I have to do before I can get things going.
     
  2. Jonathon Duerig

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    There are two kinds of calibration you need to do. First, you want to make sure that your machine is square. If it is not square, then you will be cutting ovals and diamonds regardless of anything else. There are a number of tests for squareness that you can use. If you buy a laser square, that is the most accurate way to do it in my experience.

    Second, your goal is to be able to tell the machine to move X distance and have it actually move that distance. And you will adjust your steps/inch or steps/mm setting accordingly. There is a setting on Mach for just this operation. You click the setting and Mach moves a known distance and you measure the actual distance measured and type it in. How you measure that distance is up to you. The easiest way I found is to clamp a piece of scrap on the rail snug against the gantry, tell the program to move the distance, then measure from the scrap piece to the new gantry location with a digital caliper.

    Best of luck.

    -D
     
  3. Elijah Anderson

    Elijah Anderson Well-Known
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    My machine is square, I know that for a fact. Lets say that I do the calibration in MACH3, and it changes its settings to 4000 steps per inch, do I then reflect the changes on my stepper drivers as well? or do I just leave them at 2000.

    I have not done it before, that is why this is so confusing.
     
  4. Jonathon Duerig

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    The DIP switches or jumpers on your stepper driver determine the amount of micro-stepping that happens. If you change the settings on the stepper drivers, you will then have to change your settings in MACH 3 as well. Changing this setting on the driver is just the same as making any other change to your machine, like changing the gearing or drive belt, etc.

    But the MACH 3 (or GRBL or whatever software) number is in a sense derived from the whole setup of your machine. You usually start out with some abstract number that you come up with that gets you close to the answer. Then you have to empirically measure how much actual distance each step really moves the gantry. And once the MACH 3 software knows that conversion value, it can present everything to you in nice human-readable numbers like inches or mm and translate gcode files which are inches or mm back into steps.

    -D
     
  5. Gary Caruso

    Gary Caruso Veteran
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    yeah so the 2000 on the driver is steps per 360deg of rotation.. so at 2000 you are at 1/10 micro step. the setting in the machine setup on the computer is the steps per inch or per mm (if using mm, i find the calcualtions easier in mm, and i'm an American too!). The steps per mm (or inch) will depend on whats driving your machine, belts (and the tooth count of the pulley) or screws (the lead).

    Looking at your build (very little info on it!) i think you are using TR8*8 screws from openbuilds?
    of so then i would set your drivers to 1600 (1/8 microstep) instead of 2000, then you can set your machine settings to 200 steps per mm the math is real easy that way, because the lead on a TR8*8 is 8mm per turn..
     
  6. Elijah Anderson

    Elijah Anderson Well-Known
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    Well thank you very much, I'll start from here this weekend, and report back if I have more issues.
     
  7. Giarc

    Giarc Master
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    Once you get he correct steps/inch (or mm - I made the metric leap, It is so much easier when designing things) you can fine tune it even more with a tape measure. This is how I did it and I included the formulas in the video. There are many other video tutorials out there as well. This whole fine tuning took about 10 minutes, but most of that time was spent documenting it.
     
  8. Elijah Anderson

    Elijah Anderson Well-Known
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    Got done last night, calibrated it at 30 inches on the X and the Y. 8 inches on the Z, and it all works great.

    And I snapped my first bit because I didn't understand the way the Z axis worked.....plunged into my work so hard. But, inverted y and Z fiaed it all

    Today I'll work in videos and posts for my build progress
     

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