On Tuesday 04 August 2020 21:11:56 Bruce Layne wrote: > I agree with Chris. I want the CAD model to represent the actual part > and not some fudge factor version of the part. If you don't want to > tweak the dimensions of the CAD model and you don't want to try to > tweak the printer settings which can be tedious and difficult, you can > easily adjust the scaling factors in the slicer, independently for X, > Y and Z. For a complicated part with many features, that may have you > chasing your tail, fixing one feature and wrecking another, but if you > have a simple part with only one precision feature, such as a bearing > block with loose clearance holes for mounting screws and a precision > hole where a bearing is pressed in place, you can print a copy, > measure the bearing pocket, and adjust the scaling factor for each of > the three axes and slice another part to print, all without altering > the CAD file. > > I don't think tramming is a thing with FDM 3D printers. The tool > length and tool diameter are on the order of the nozzle diameter so > tramming errors should be fairly insignificant. The extruded filament > may slip a bit to the side if dispensed along a vector that's slightly > misaligned to the Z axis but I think most of those small errors would > cancel, with only a very slight distortion to the circumference of a > vertical hole. If you level the bed to the nozzle with three or more > points, the bed will be perpendicular to the Z axis so you should see > no large scale errors across the part's surface as you'd have if, for > example, you were fly cutting on a milling machine that wasn't > trammed.
This is a tilt to left or right, of the x axis travel bar. Enough error there equals the floors of the leaning tower of Pizza not leaning the same amount as the tower is. In other words the walls can be vertical and likely are, but the floors are leveled to the tilt of that x bar by compensating adjustments to the bed level screws. > > On 8/4/20 7:52 PM, Gene Heskett wrote: > > On Tuesday 04 August 2020 16:13:52 Bari wrote: > > > > I finally got around to measureing the 5x5 cube I did this morning. > > X=5.31mm,10.40,15.45,20.58,25.55 > > Y=5.25,10.35,15.40,20.4925.62 > > Z=brim 0.70,5,61,10.54,15.57,20.43,25.39 > > > > The top 5x5 has a fat spot near its bottom that reads almost 5.9. > > Only in X. I was not in the room at the time. brim is too thick. > > Raise glass. And scale. > > > > So I need to subtract a bias from xy to even get in the ball park. > > And add a teeny bit to Z. > > > > And this was after I had taken it apart to see in I could improve > > the tramming which I did a considerable bit of, Z moves a lot easier > > both ways now. MUCH less binding between the 3 point trolleys now. > > But I can't find anything that could be miss-construed as bias. > > Home offsets, yes but no fixed subtraction to compensate for bias. > > Cura post processor job? Is there such a critter? > > > > Thanks all; > > > > Cheers, Gene Heskett > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
