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jkarnacki's MKIII

Discussion in 'General Phlatprinter 3 Chat' started by jkarnacki, Nov 6, 2010.

  1. jkarnacki

    jkarnacki Member

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    Thank you, Flash. I'll have to try that if I continue to have problems. In fact I should probably do that right now with the right handle as it's still sticky. I actually cracked the right handle where the handle goes into the two laminated pieces. It's still intact so I'll wick some CA into it and spread some epoxy over the top. This is exactly why I wanted to wait until I completed my build to PM Mark the part numbers I needed replaced. I knew I would break something else :D. This has been pretty frustrating, but each time I fix one problem it feels pretty good - one step closer! My x axis stepper motor just stalls as soon as I lower the rollers onto the foam. I tried different tensions on the belt, lining up the pulleys better between the grip rollers and the stepper motors, and lubing up the brass (?) collars that the rollers slide through. Was that graphite that came in the inside of the collars? I didn't hear it mentioned in the build videos but maybe that's what it was. I scraped it out, though, because I thought it was some loose magnet fragments. What I ended up doing was getting the rollers to spin as freely as possible (not the rollers with the grip tape, but the top rollers), as well as increasing the voltage to the x axis stepper motor by less than an 1/8 th turn on the pot. Maybe the rollers will wear in over time and I can drop the voltage again.

    I swapped the pulleys on the Y axis and it jogs freely now, albeit slowly. I still haven't taken the gantry off to inspect it (as per Mark's suggestions) but I need to do that to see if I can get it to work properly (and faster!). I've noticed the grub screws on the pulleys are already starting to strip, so I'm going to home depot tomorrow to get replacements with a larger head.

    I think I'm not too far from my first cut...hopefully a successful one. I need to get back to flying! :D

    Hmmm this forum is strange. I hit the submit button (not preview) last night before I went to bed but it didn't go through. I always seem to have to hit submit twice before it actually posts...
    - Jeff
     
  2. Anonymous

    Anonymous New Member

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    Jeff, How close are you to another PP owner? Are you on the PhlatMap?
     
  3. jkarnacki

    jkarnacki Member

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    I'm about a 90 minute drive to your house. S.F. Bay Area. I thought about having you drive over hear to help me, lol. But I think I'm well on my way, now :D

    - Jeff
     
  4. Anonymous

    Anonymous New Member

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    90 minutes eh? Are you north of San Francisco?
    There is at least one other in the south Bay area (AlphaGeek) who is (or will be) building a pp , and a few of us PP1, PP1.5 and PP2 owners nearby also. In other words, you are not alone, just ask for help if you need it. :)
     
  5. Gefahren

    Gefahren Member

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    I was having problems getting my X axis to drive with the pressure rollers lowered also, plus my Y was stalling out. I thought the Easy-CNC board was preset for what was needed since the current pots were turned all the same way. But when I checked it after scratching my head a bit I found them set to 1 Volt instead of 4 volts, so I was only pushing a half amp of current in the steppers. After changing that, all three axis are running fine (even without switching the Z pulleys around).
     
  6. jkarnacki

    jkarnacki Member

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    WOOT! I made my first cut a few minutes ago. Tomorrow I'll upload the video to share with you guyz. The foam came too far out of the machine and came off the rollers, not quite sure why, but I'll figure it out :D

    Where is the setting in Mach 3 to make the spindle come to a complete stop so that it does not round corners? Or is this impossible with an 1/8th in bit...

    - Jeff
     
  7. jkarnacki

    jkarnacki Member

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    Tried the cut again and this time it went through the entire sheet, no problems. The bit ended almost 1/2" from where it started in the y direction and 1/4" in the x direction. The sheet ended up skewed by about a 1/4 inch on one end. Do I just need to double check my calibration or could there be something else going on? I also noticed that the stepper motors on my X and Y axis were almost too hot to touch for more than a couple of seconds. I have the voltage on the driver card set at 3.3 V on all axis, which should translate to about 1.6 amps. What do you guyz suggest I check?
     
  8. Flashsolutions

    Flashsolutions Active Member

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    Gefahren and jkarnacki, 4 volts is way too much for those steppers. I seem to remember something more like 2.6 volts. Those steppers should run cool to warm at most. NEVER hot!

    IT IS ABSOLUTELY CRITICAL THAT YOU GET THE VFD SETTING ADJUSTED PROPERLY. YOU WILL DAMAGE THE STEPPER IF YOU RUN IT HOT AND NO AMOUNT OF ADJUSTMENT AFTERWARDS WILL HELP.

    Also, do not leave the power on in idle mode for extended periods. The Mecktronic boards have no current limiting and the steppers can overheat just sitting there doing nothing.

    Since I use a Gecko controller rather than the Mecktronic controller, my current adjustment is via a fixed resister. I don't remember the specs for the vectra steppers but it should be documented in one of DVD's that shipped with your kit.

    There are many many things that can cause problems such as you are having. Binding, Calibration, too little stepper current (not in your case), alignment issues, etc.

    The forum has many posts from past MK1 and MKII builds which cover most of the typical problems.

    The best advice is to go thru every step which deals with an area you are experiencing problems. Watch the video again and check to be sure you did your initial build correctly. Pay particular attention to those steps which deal with an axis you are having issues with.

    In the case of the Y axis, you are dealing with the gantry build, the mounting to the I-Beam, calibration, and controller setup.

    Concentrate on one area at a time. If you were having problems during the build and just continued on, you will undoubtedly have more problems at the end.

    The good thing about the Phlatprinter is that you can disassemble everything, so it is possible to resolve most any build problems you may have.
     
  9. Flashsolutions

    Flashsolutions Active Member

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    When you are bringing up a new machine, you want to start out slowly. Walk before you run as they say.

    Go into Sketchup and make yourself a simple 2" square. Try cutting that out first. Then move up to a square and a circle. Then do some stairsteps. Then recalibrate using longer runs, fine tuning till you get an accurately cutting machine.

    Start out slow at 20 IPM and work up to higher rates as you get your machine tuned up.

    There are calibration settings to control ramp up speed and acceleration, steps per inch, etc that all need to be fine tuned to establish a working CNC machine.

    It is all too tempting to just start cutting out foam planes without going thru the basics first. Then when you have wasted a full sheet of foam and your cuts don't line up, etc, you have no reference as to where to start looking for problems.
     
  10. rcav8r

    rcav8r Moderator Staff Member

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    I have mine set at 2.6V. and the machine runs fine. Well the Z has the pulleys reversed, but that is a separate issue with mine. The steppers are 1.4Amp the way we are using them, so that would be 2.8V at TP1, but I backed mine down a bit to help the board and steppers run a little cooler. I don't have my fan hooked up yet, and the heat sinks on my board and steppers were barely warm to the touch.
    When I built my MK1 I was having a problem getting past 20ipm ( yea the good old days when we were shooting for 30ipm :) ) I though I could sneak the voltage up a bit to help the speed a long. In short order the stepper froze solid. I took it apart and one of the winding was a crispy critter. So head Flash's warnings.

    One of the DVDs has the configuration file for Mach3. I used that, and my x and Y axis were spot on. I did have to change the settings for the Z as I reversed the pulleys, but I set up the curve to mimic the X and Y, and it's working great.

    The skewed X axis could be un-even heights of he X rollers left/right.

    With any sized bit you will have rounded corners. Just the nature of the beast when cutting with a round tool.
     
  11. Gefahren

    Gefahren Member

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    Ok, I got the two amp setting (4.0V) from the specs listed for the stepper in the phlatboyZ store. The documentation said set the voltage to twice the desired current, so that's what I did. I did't find the part on the DVD's that gave any more details on setting up that board besides it's simple manual, or stepper specs. I do agree that they were running hot.

    As far as adjusting the PFD, any suggestions for a procedure to do that? I have some Gecko drives for another project (same as inside the 540) and have tuned them out, is the procedure about the same for the Mechatronics?
     
  12. rcav8r

    rcav8r Moderator Staff Member

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    Those specs are for Unipolar configuration, we are using them in Bipolar configuration ( 2 wires not used), so the current is 1.4Amps. Attached is a spec sheet for the stepper. See current Spec for (b) , not voltage spec.

    As far as PFD, I did what the manual for the Mechatronics board said..I forget what that was now. Attached files PK266-02A.pdf (339.4 KB)Â
     
  13. jkarnacki

    jkarnacki Member

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    Thanks guyz, I'll lower the voltage on all motors (hopefully they're not ruined) and then work on one axis at a time trying to isolate the problem on smaller cuts. Less wasted foam...I like that.

    - Jeff
     
  14. Gefahren

    Gefahren Member

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    Ahh, I wasn't paying attention when I looked at the specs listed, I SHOULD be smarter than that. I changed all mine down to 2.6V and they all seem to be running fine, even the Z which seemed abit tight at fist but seems to be getting better.

    I used a ruler to measure how far the foam, or the Y or Z carriages had moved, that way I wouldn't waste foam until I was sure it was close.

    As far as what the manual says about adjusting the PFD, it basicly just says that you can. Should I adjust it while the motor is sitting idle and just listen for a "resonance" or should I do like the gecko's and have the motor turning at 1 RPM and listen to it?
     
  15. jkarnacki

    jkarnacki Member

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    All axis are now at 2.4 V. My Y and Z axis are calibrated and return to home after multiple jogs. My X axis, however, will skew the foam after just 20 inches of movement. After a run to the end of the foam and back on a full sheet of FFF, the right end (facing the machine) is off by 1/4" of an inch. It always seems to be the right side that is off. I used two stacked washers under each roller per the build videos to adjust the height. I had my dad help me hold the rollers up to just barely touch the rollers while I tightened them down. Sitting the machine back up, with the washers still in place, the grip rollers still appear to be in perfect position, but I'm still getting skewing even over relatively short X runs.

    - Jeff
     
  16. 3DMON

    3DMON Moderator Staff Member

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    Try raising the rollers up a little more.
     
  17. kram242

    kram242 Administrator Staff Member

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    Jeff you have to be sure that the rollers are above the height of the cutting surface through out their rotation cycle. In testing I tried to get them just even with the cutting surface and had a skew problem but with the 2 washers on there it will raise the dive rollers up above it and it will eliminate this problem. If two washers are not enough try going a little higher and then try the x and you should be fine.
    Mark and Trish
     
  18. Flashsolutions

    Flashsolutions Active Member

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    You are missing two lock collars which were sent out yesterday. Without them, your rollers can slip side to side. This could be one source of problems.

    Another thing to check is how you applied the non-skid tape. Did you spiral it or put it on in straight strips?

    I am not exactly sure what you mean when you say the X is off by a quarter inch on the right side since you say the Y and Z return home fine.

    Can you explain your problem a bit more.

    It is hard to determine skew without some reference points. For starters, I would mark up a sheet of foam with a line drawn 90 degrees from the short edge using a builders square, place it in the machine and make sure the front edge is exactly parallel with the front of the table. Then lower the pivot arms, and run the gantry down to where the bit is just above the line you drew. You can now move the foam along the X axis and observe if the bit tracks the line drawn on the foam. Then if it does skew, is it off at the end of the run or is it off when the X axis returns back to home position.





     
  19. jkarnacki

    jkarnacki Member

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    "Another thing to check is how you applied the non-skid tape. Did you spiral it or put it on in straight strips?"

    Mark mentioned putting on the grip tape in a spiral rather than straight strips, so I tried that but I didn't think I would be able to get it on perfectly without overlapping, so I ended up putting them on in straight straights with no overlap, but I will definitely double check that to rule that out.

    "I am not exactly sure what you mean when you say the X is off by a quarter inch on the right side since you say the Y and Z return home fine."

    What I have been doing is placing a sheet of FFF in the machine and lining it up perfectly with the edge of the machine, i.e., the small lip that hangs off the end, so the edge of the foam is parallel to it. Then I jog the x axis until the foam is at it's limits (even shorter runs produce the same problem), then jog it back to it's starting position. Here is where I notice the skewing. From the front of the machine, the foam is no longer parallel with the edge as it was before I jogged it. The right side of the foam has been pushed towards the machine, and the left side has been pulled off the edge of the lip.

    It seems like I would be missing four lock collars, though. Shouldn't there be four collars for each roller? I'll have to check, maybe I am only missing two. I don't remember :roll:

    - Jeff
     
  20. jkarnacki

    jkarnacki Member

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    I tried raising the rollers to three washers high (they were two) but it didn't help. Should I go even higher, or do you think the side to side movement of the rollers is the problem? Right now they are free to move side to side as they wish, which, at least intuitively (is that a word?) would make sense why I'm getting skewed movement.

    - Jeff
     
  21. Flashsolutions

    Flashsolutions Active Member

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    Putting the tape on straight rather than spiral would be my preferred method. That more or less eliminates the spiral of causing skew issues.

    My best guess is the missing lock collars assuming your rollers are flush against the pivot arms and the pivot arms are straight.

    Double check that the pivot arms are parallel with the top and that the rollers are the same height on both left and right ends.

    If all that is correct, wait for the lock collars and then install them or you can go down the hardware store and pick up some 1/2" flat washers to fill the space on the left side of the rollers between them and the MDF support. Eight should do it, four per roller.

    I think this is a better way to do it anyway as the lock collar is a bit too wide and leaves the roller pulley pushed over to the right a bit far.

    With the washers providing the spacing for the left side, you can eliminate the two missing lock collars and it actually aligns the right pulley with the stepper pulley much better.



    Attached files [​IMG] [​IMG]
     
  22. jkarnacki

    jkarnacki Member

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    Thanks for taking the time to post those pictures, they really help me see what's going on. I'll try the washers tonight and a sheet of foam with a line perpendicular to the edge and report back.

    - Jeff
     
  23. jkarnacki

    jkarnacki Member

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    So far I've cut out a Lil' Ripper and a 22" Skyray. The Lil' Ripper came out with the two fuse sides slightly off, one a little bigger than the other but still flyable. The Skyray is nearly perfect. I did notice, though, that the tab width for tab-n-slots should probably be a little less than .25 in, otherwise they hang out of the the opposite end of the foam a bit much. These tabs-n0slots sure help with building straight!

    Now that my excitement has calmed down, I need to finish up with the fine tuning. I still need to adjust the roller heights a little more to get rid of the slight remaining skew as well as put the new Z axis parts on that Mark sent me. I'll let you guyz know how I make out.

    - Jeff
     
  24. jkarnacki

    jkarnacki Member

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    I out the new Z axis parts on and the alignment is still a little bit off but the rod is much easier to turn by hand now.

    I'm still having skew problems, though. I've adjusted the rollers countless times now, and they are PERFECTLY even. I'm still getting skew! I've even tried a nice flat sheet of depron to rule out the inconsistencies in the foam, but it didn't help at all. No matter how I adjust the rollers (I've tried adjusted either side slightly higher than the other) the foam always skews in the same direction. The edge of the foam near the x stepper motor always moves IN towards the machine, and the left side of the foam always gets pulled OUT.

    What oh what do I do?

    :x

    - Jeff

    <EDIT>
    Forgot to mention - I did trim a little bit of the grip tape where it might have been overlapping, so now there's a tiny (~1/8" gap) between the sheets of grip tape...that didn't help either.
     
  25. jkarnacki

    jkarnacki Member

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    I tried raising the rollers to three washers thick, but the machine won't allow me - the x stepper motor belt is only long enough to raise the rollers to two washers thick.

    - Jeff
     

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