X, Y step calibration object with holes

thingiverse

This object serves a crucial purpose - calculating the X and Y motor steps to perfection with horizontal expansion settings. Its dimensions are carefully designed: the longer side measures 45mm, while the shorter side spans 30mm. The holes come in two sizes, measuring 20x20mm and 10x10mm respectively. When utilizing horizontal expansion, it's essential that both hole and outer dimensions align. If the hole dimension is A, its expanded size becomes A2 = A-2He. Similarly, if the outer dimension is B, its size will be B2 = B + 2He. Consequently, A2+B2 = A -2He + B -2He = A+B. To calculate expansion, simply use He = (B2-B-A2+A)/4. Therefore, to calibrate X and Y steps accurately, you should ensure that the sum of one hole dimension and one outer dimension in each direction is correct. For instance, if printing with the longer side aligned along X, you would want to calibrate it so that Xout + Xbighole = 45+20=65mm, and Yout +Ybighole =30+20 = 50mm. New steps are calculated as follows: Xnew=Xold*(Xout + Xbighole)/(Xoutreal + Xbigholereal) and Ynew=Yold*(Yout + Ybighole)/(Youtreal + Ybigholereal). Expansion values, Hx=(Xout - Xbighole -Xoutreal + Xbigholereal)/4 and Hy=(Yout - Ybighole -Youtreal + Ybigholereal)/4, must be adjusted by multiplying them with Xold/Xnew and Yold/Ynew to yield accurate results. Since these expansion values are close to 1 and usually low, old steps remain usable. However, the slicer I'm using (Cura 4.2.0) only offers one expansion value; therefore, a mean value He= (Hx+Hy) / 2 should be calculated. This is a starting point for your prints, but you may need to tweak the expansion values for someone else's files to achieve the desired gap between components. For optimal results with this object, use calculated expansion and new steps to print it again; your outer dimensions should be correct if properly calibrated. You can also use this cube: http://www.thingiverse.com/thing:1278865 as a reference point for tight fits. Alternatively, you may consider using this larger object (https://www.thingiverse.com/thing:3882150) to measure XY steps more accurately in bigger objects; however, it will take longer to print due to its size of 150mmx150mm.