Re: 3D Printer (Prusa Bear Mod) Build
Posted: Tue Apr 26, 2022 11:13 am
So, a couple posts back I mentioned maybe working on the extruder unit next, which is a different mod than the bear frame, even though they were both designed by the same guy. The Bear Exxa (extruder/x-axis) can be installed on a standard Prusa, and conversely a Bear frame modded Prusa can use the bog standard Prusa extruder and X axis. Really the main reason I am going with the Bear Exxa is it lets me use the 10mm Z rods, which will stiffen up the 100mm taller Z axis a little. This has me jumping back and forth between the assembly guides for the Bear frame and the Bear Exxa, and in the end it made more sense to assemble the Z and X axes first. At least it got some of the parts onto the machine and off the workbench.
In the meantime, here is a preview of the printed parts that go into the extruder. These are all black PETG with the exception of the part cooling fan shroud (upper left), which is printed from ASA (an ABS variant that prints a little better) for additional heat resistance. I printed up an extra of these since it is the printed part that is most vulnerable to heat damage.
These are all printed in black instead of the blue, because the extruder uses an IR filament sensor that lets the controller board know if the filament runs out. Only some of the parts need to be black, but I figured having pieces of both colors in the same assembly would look silly.
Printer as it sits now. Same deal with the X motor as the Y; I ordered the wrong parts, so I am going to have to wait a few days for the new drive pulleys I need to install the belts. The extruder will ride on the 3 bearings you can see on the X rods. The orientation is marked on the back with sharpie marker so I can turn them the correct way. The idea is to have them turned 45 degrees from straight up and down, so the weight of the extruder will be supported by 2 rows of balls at 1:30 and 10:30 for better wear characteristics than having all of the weight on a single row at 12:00.
In the meantime, here is a preview of the printed parts that go into the extruder. These are all black PETG with the exception of the part cooling fan shroud (upper left), which is printed from ASA (an ABS variant that prints a little better) for additional heat resistance. I printed up an extra of these since it is the printed part that is most vulnerable to heat damage.
These are all printed in black instead of the blue, because the extruder uses an IR filament sensor that lets the controller board know if the filament runs out. Only some of the parts need to be black, but I figured having pieces of both colors in the same assembly would look silly.
Printer as it sits now. Same deal with the X motor as the Y; I ordered the wrong parts, so I am going to have to wait a few days for the new drive pulleys I need to install the belts. The extruder will ride on the 3 bearings you can see on the X rods. The orientation is marked on the back with sharpie marker so I can turn them the correct way. The idea is to have them turned 45 degrees from straight up and down, so the weight of the extruder will be supported by 2 rows of balls at 1:30 and 10:30 for better wear characteristics than having all of the weight on a single row at 12:00.