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X2 Mill Cnc Conversion

Discussion in 'CNC IN THE HOME SHOP' started by shooter123456, Jan 10, 2017.

  1. shooter123456

    shooter123456 United States Active Member Active Member

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    I have been working for a few weeks now on a CNC conversion of my X2 mill. Originally, I was going to stick to manual for a while, but after making a power feed with a stepper motor, a full cnc conversion seemed inevitable.

    As with anything, budget was a concern, and any money I can save on the conversion is money I can spend on stock and upgrades. I know its a HF mill so my expectations of it aren't super high. I know I won't be making parts accurate to .0005". If I can hold .003" or better, I will be pleased.

    For the controller, I am running linux CNC on an oldish computer my boss and I built from spare parts when I was an intern at my company. It isn't a workhorse computer, but it seems to be good enough. I found an old mac keyboard tucked away in my parents attic and snagged an old 19" monitor from work. I also gutted a very old (Probably around 2000) computer to use the case to house the CNC electronics.

    For the motion, I am using 400 oz in Nema 23 motors on all 3 axes, TB6600 drivers, and a 7.3A 48V power supply. I got an el cheapo break out board for about $10 on ebay to interface the computer with the drivers. It is optoisolated, is powered by USB, and communicates with the parallel port.

    I ordered some 1605 ball screws on ebay for $160 for all 3 axes and got them installed. I haven't measured the backlash correctly yet, but when I use the DTI and order a .001" movement in the opposite direction, the DTI indicates .001" movement. At the very least, it should be close to 0 backlash. I am using thrust bearings in the X and Y axis, and 2 "angular contact" bearings for the Z axis. I have the X and Y mounted, wired, and moving, and I am working on fabricating the Z axis at the moment.

    The ball nut took away some movement in the Y axis. I am getting right around 3.9 inches now. I will break out the grinder and remove some material from the base to get that back. I should be able to get to 4.75 easily, maybe 5 if I really push it. The X is getting 9.75 without overtraveling the ways, and maybe 10.5" while overtraveling one direction safely. When I finish the Z, I should gain 1.5" of travel at the top.

    The X and Y have no trouble rapiding at 108 IPM, and when setting up, it was able to get to 5 inches/sec (300 IPM) before it started to stall, but it didn't seem to be going that fast. I may have been losing steps at some point. Though 100 IPM is plenty for me.

    I still have a good bit of work to do, and I will have a lot of questions. I am going to do the hoss pneumatic tool changer once I finish the Z axis and I got a 1.5"x36" piece of 4140 for christmas to make a bunch of tool holders.

    Here is what I have done so far.
    sc61T20.jpg

    Here are the parts I have made for the Z axis so far.
    MZWOpwe.jpg

    Here is the whole set up on the bench.
    KwQ82tA.jpg

    This video shows the X and Y axis motion.


    Here is a facing cut in 6061 aluminum at 60 IPM and .003" depth of cut.


    Here is another cut, roughly .5" deep at I think .01" wide. Please pardon the overlay and the vertical video.


    Im happy to answer and questions and I am open to tips and suggestions if anyone has them.
     
    jbolt, TomS and rdean like this.
  2. shooter123456

    shooter123456 United States Active Member Active Member

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    I got the Z axis stepper and ball screw mounted up and attached yesterday. The ball screw I got for it is oversized, but it doesn't look like it will get in the way of anything so I am not going to mess with it. I couldn't figure out how to remove the Z axis rack and pinion handle to make some measurements for a block to attach the nut and the head. I have a big block of scrap aluminum (the one seen in the test cuts) that I will probably square up and bolt to the side of the head, then take a piece of 3/8" aluminum bar, drill and tap to attach the nut, then bolt it to the protruding block. It will limit (or eliminate) the ability to adjust the Z axis gib screws so I will have to learn to live with that or come up with a better way.

    For the Z axis, all thats left is to wire it into the driver, make the coupler, and make the blocks to attach the head.

    Here is a picture of the stepper mounted up. I will need to make a small spacer to tighten down the ballscrew to the bearings.
    R2Biect.jpg

    Here is a wider view of what I have now.
    Jv2iMfM.jpg

    I plan to come up with a better way to cover the ways sometime soon, maybe something that will protect the motor and coupler as well. Since I have been working on the parts with the ways uncovered and Y ball screw exposed, its going to need to be removed and cleaned. I will grind the base when I do that to get my Y axis travel back and hopefully get a decent increase as well. I plan to make a few parts with it before I do the flood coolant and enclosure. Too excited to wait while I do those... I should probably think of the time as an investment since clean up will not take 15 minutes at the end of every day. I don't think the bench is going to cut it for these machines. When I built it, it had my 90 lb mini lathe and the manual mini mill that I ran pretty slow. When I make cuts quickly with the CNC, the whole table shakes and rattles. When the Y axis rapids, the entire table gets pulled back and forth. Then the 450ish lb PM1030 is too much as well.
     
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  3. Boswell

    Boswell United States Hobby Machinist since 2010 H-M Supporter-Premium

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    Shooter, It looks like your moving along quickly. Looks like a nice build.
     
  4. shooter123456

    shooter123456 United States Active Member Active Member

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    I appreciate that. I have all week while I am at school to think about what I want to do to and with the machine so by the time it comes around for me to head to my parents house to work on it, I have a specific plan worked out for what I need to do. It seems to make things go pretty quick.
     
  5. shooter123456

    shooter123456 United States Active Member Active Member

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    I am so close I can taste it... I have the Z axis mount done and mounted up, the Z axis stepper coupler machined and ready, the Z axis head block drilled, tapped, and in place, and the clearance hole for the ball screw drilled. Just need to drill and tap 6 holes for the ball nut, and make a small spacer for the lead screw and I should be in business!

    I had a bear of a time removing the rack and pinion feed and handle. Once I had removed all of the hardware I could see, I couldn't get the rear cover to budge. I hit it probably a dozen times with a dead blow hammer, I tried to smack a screw driver between the head and the cover and launched a screw driver to the other side of the garage, and spent a good 30 minutes trying to figure out what else was holding it on. Once I concluded after spending a good amount of time online looking at pictures that there was nothing else holding it in place, I got a 10 pound sledge hammer and get it 2 taps and it broke free. Im thinking they stuck in on there while the paint was still wet and that bonded it to the head. Well from there it was just lining up 2 holes then drilling and tapping the head for the mounting screws, and drilling the through hole. I will enlarge it on my lathe because it is slightly misaligned and the largest drill bit I have is .750. It may rub on one side if I don't correct it.

    Here are the pictures of the progress.

    HAj8fuB.jpg

    HAj8fuB.jpg

    I had the table off so I got started on grinding away the base with a dremel tool and thats going to take forever. Unfortunately, I can't think of a faster way to do it with the tools I have. I want to get that Y axis travel back.
     

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