Tramming cylinder printer test

thingiverse

Tramming is usually done on milling machines, but on printers it can be quite extreme. Every print we make is like a leaning tower of Pisa, and this test lets you measure how much that is. Honestly, this only matters if you print threads or gears or parts that bolt together. The idea behind tramming is to make the three motion axes perpendicular to each other. Inexpensive printers often do this with software, which can create print artifacts. With this test, you can verify how well the software's tramming functions or go the extra mile and correct the printer's mechanical inaccuracies. This test is for a well-functioning printer. Your first printer test should be X-Y calibration, which is all about printing round cylinders or right angle squares, then an extrusion calibration test. Configure your slicer to NOT support threads and 30 degree overhanging surfaces, or just turn off supports! Print the cylinder on a raft, marking its orientation to the table with a felt pen before removing it from the build surface. Print four nuts. Print the base but don't remove it from the build surface for the remainder of this test. Bolt the cylinder to the base, positioning and locating it only by the tapered surfaces and not the flat bottom so you can sand the cylinder bottom if needed. Use a dial gauge - China quality is more than adequate for a printer, with prices starting at $15 to $20 on eBay. Make a reference measurement near the top edge of the cylinder at layer height where there are no printing artifacts or surface bumps. Twist the gauge face and make this the measurement point zero. Next, unbolt and rotate the cylinder 180 degrees, then re-bolt it carefully without bumping the gauge or any axis. If you do mess up, just repeat both measurements. The measurement rotated and not rotated should be the same if the printer is well-trammed either by software or mechanical adjustment. Repeat the measurements for the other horizontal axis. The difference measurement you make is twice the leaning inaccuracy - so if you want to adjust the axis, correct only half of this difference. It's not actually that straightforward an adjustment because the vertical axis pivot point isn't at the base of the print. When done correctly, the Z-axis will be perpendicular to the horizontal extruding layer plane. Then, you can run the Z-axis up and down with the dial gauge measuring changes in the cylinder distance - but if adjusted correctly, the readings on the dial gauge should be constant. Rotating the cylinder in 90 degree steps also produces a constant measurement if the printed cylinder is round. Lastly, to verify mechanical adjustments, reprint everything except the nuts. If all goes well, keep the final cylinder and nuts as a master reference and only print the bolt base to tramm other printers. If you happen to own a gauge block set, that's what I use now - https://www.thingiverse.com/thing:3843188 Printed using a 0.1 mm layer with a 0.4 line width, designed in Fusion 360 and printed to adjust a Cetus mk2 extended. Have fun, Peter