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jleichne

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  1. I'm in need of such fine precision since I am working towards tissue & organ printing. I was hoping instead to use this section of the forum to discuss the advantages of each of your individual setups, in repeatable mathematical ways so as to truly test if, for example, direct drive will improve my variability enough to warrant setup. J
  2. Oops - can a mod please delete the other topic, it seems to have duplicated after I went in for an edit and added a few numbers that I had left off the first post.
  3. Hey there guys, I was here a while ago asking around to find some hard numbers on the printers accuracy, precision and backlash. Nobody really had much, so I picked up a gauge dial and did a series of measurements on the three axes. I was hoping to begin a trend here where people can measure and post the qualities of their machine, in order to begin devising a database of average assembled machine quality. In addition, this can really help give some true figures on the advantage of the direct drive design, the GT belts and pulleys, or any other combination of parts. So I guess I should
  4. Hey! So I want to remove the Bowden tube from the hot head so I can attach it to a new mount for a syringe-extrusion setup. How do I go about pulling it out? Do I need heat? Do I need to hold down a little white thing like when you remove the bowden from the back extruder? Thanks! I'm cautious about pulling too hard before asking the community. Jared
  5. Hey yall' Two things: (1) I'm wondering if there is a good online resource for understanding the numerous commands in GCode. I know there is a list of all the commands but I haven't found any simple tutorial (although if there isn't I'm ready and willing to dissect the GCode of basic circles and squares for starters) (2) I also want to update the firmware for Marlin, I've used Arduino environments before but before I start wading through the source code blind I would like to find a good resource. I plan to add additional printheads and I want to be able to add in the functionality of mo
  6. Based on my calculations, 78.74 steps per mm is equivalent to 12.7 micron steps. Is this with or without microstepping? In addition, the largest source of error is probably the backlash (which I wouldn't be surprised if it was anywhere between 15 and 50 um. I want to switch out the pulley system too and use ballscrews with minimal-backlash nuts. I'm okay with near-perfect positioning at the cost of speed.
  7. To make sure I understand you correctly, you are suggesting removing all the belts and making the two axes parallel to the two ball screws driven by the sheer force of the ball screw on the opposite side (meaning I will need to replace the opposite wooden blocks with something on a super frictionless bearing). I feel that while this will better level the printhead, it will probably cause strange torque beyond a particular load I am applying at the printhead. (Still need to run simulations) This is more or less my current plan already - although since I'm going to be reworking the frame
  8. True - I've needed to adjust those, but the grinding sound was happening only during the initial motion towards the center of the bed after homing. (but its now gone away as mysteriously as it came)
  9. How low can it go? I've seen the difference between the 0.2 and 0.1 setting, but how low can it be put? At some thinness I presume the error in filament regularity overpowers the resolution - but where is this limit? J
  10. Alaris: I didn't plan to add any extra axes. I will add a photo later when I have more time. My plan is to simply replace the particular X and Y axis that is timing-belt driven with a long ball screw. A similar belt system will pull the block on the opposing two axes. This will combine direct drive with a ball screw and I believe the two axes driven by belts will have much less of an impact on error than the ball screw. Snowygrouch: I'm happy to see that you've also considered this. I agree that its definitely not a speed-friendly approach, but for my purposes (small-diameter arteri
  11. Hey yall' My printer used to be perfect and quiet. Real quiet. I've only had it assembled for a week and everything has been great. Two things have happened recently: (1) I set my printer to the bottom for the first time and the bottom Z switch didn't activate perfectly, creating an ugly grind sound for the half second it took me to turn off the machine. (2) The timing belt pulley on the Y axis became so loose earlier that it messed up a print. I retightened it with amazing results at first. I just found it slidable again only a few hours later! So here's the problem: Running Cura,
  12. (3) Keeping the timing belts and replacing the pulleys on the main XY axes with ones that are twice as large in order to double the theoretical precision of the device.
  13. I agree that direct drive is a crucial step in removing an unnecessary source of error. How do you feel about the following two adjustments as well (in tandem with direct drive): (1) Using Ground Ball Screws to drive two primary axes and the belts and pulleys to respectively drive the parallel two axes. This may drastically raise print times but do you believe it will achieve a more reliable, consistent accuracy over solely direct drive. (2) Adding two more vertical beams like those to the sides of the main vertical leadscrew at the front of the device to better stabilize the pla
  14. Thanks for the quick and thorough reply, however a few things: (1) "The bed moves around about half a mm at the front under severe jerk forces during printing" Is the jerk force in the direction of the Z-axis twist? If it was possible to add two more rods and linear bearings to the front could this be accounted for and removed? There's definitely room for it, that's for sure. (2) "the frame is made of wood, which will be expanding and contracting with humidity all year round" I will be recasting all of it into acrylic so I can do cellular printing. I will also be changing the printhead
  15. In another post, I tried to describe a mathematical model to describe my error: Final Position (along one axis) = (Xo) + Etiming + Elong Xo = what software considers the initial position Etiming = Positional Error due to (1) Slip of timing belts and (2) Improper Orthogonality of Timing Belt to Long Belt Elong = Positional Error due to (1) Slip of long belt, (2) Improper orthogonality of both long belts (Also errors due to parts not being screwed in tight but is removed due to simplicity) Would you agree with this simplistic description? I also came up with what I consider to be a reliab
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