PrntDGW

thingiverse

I started from AndyCart's PrntQB V2 nine months ago and have been making incremental upgrades to reach this point. Key features include: The offset pulleys at the front eliminate string friction, a factor that doesn't impact corexy geometry. Aluminium carriages are used; I initially tried a printer for the first set but found it struggled with straight holes, so I switched to a milling machine. The X and Y carriages are 75mm wide, significantly wider than the initial 25mm models, which resulted in considerable slop at the print head. Bushes are simply turned on a lathe from nylon rod with an 8.1mm hole. I'm currently experimenting with dry lubricant to protect silver steel rods from corrosion. The small 623 bearings exhibit significant looseness; the 625 ones perform much better. After trial and error with the Z drive, I found the best configuration involves butting the threaded rod against the motor shaft inside the flexible coupler. A bearing at the bottom prevents the rod from descending when lifting the carriage. Separate brackets for the Z axis allow spacing to be determined solely by the carriage. I've switched from a straight drive pulley to an eight-shaped idler, which stops string movement on the pulley and accuracy issues caused by changing angles. However, this has been problematic; the drive string shows signs of creep on the pulley, causing subsequent layers to become misaligned. I have since reverted to the old system with a plain pulley and no idler, which works better but still suffers from some inaccuracy (about 0.3%). Video: https://youtu.be/n_YZ6EtYQfY Edit: Thingiverse isn't allowing me to post comments; in response to mbthor: Thanks for the feedback. I've uploaded a video showing the printer before reverting to the old drive system. The grooves were made using a tool with an insert featuring a 0.5mm radius, resulting in rounded edges. My idler bearings and supports are suboptimal and not entirely vertical, which might contribute to the issue; alternatively, it could be due to the increased length of line between the input and output of the drive system.