The standard X Axis idler pulley achived by a ordinary bearing was removed and replaced by a toothed pulley. Additional i decide to change the T5 belt to a precise GT2 belt system. By virtue of this modifications i had the need for a new device holder. I have two different version provided. One explicite for GT2 assembly, the other for any kind of pulley with variable mounting options.
You can download the parts here
Description for the GT2 solution only. You need:
2 x ball bearnings 625, or similar with 5mm inside, 16mm outside
2 x washers with 5mm diameter hole
1 x M5 Screw with nut, at least 30mm length
1 x GT2 Pulley, 20 Teeth and 5mm inside diameter
2 x M5 Screws with nuts 10mm for mounting on frame
For assembling see pictures above. Note to put the motor down for about 5-7 mm by rasping long holes in the aluminum angle or download a new holder from thingiverse.
ATTENTION: Keep in mind, that the intersection of the new GT2-X belt is very close to the T5-Y belt! You need to adjust both correctly so they do not touch.
I´m working on the second part of the GT2 solution for the Y-axis. Hope this will be ready as soon as possible, but caused by the original construction it is a little bit more tricky
Nice brackets, and the bearings are certainly a good idea. Have you thought about incorporating a belt tensioning mechanisim into your bearing hangers. Let me know if you want to pursue this idea. I can post some sketches.
some belt types tend to vibrate (at certain speeds) when combined with a smooth idler. The reason for this is the variation of the effective radius at the point where belt and idler surface “meet”: the bearing does not support the lower, i.e. gap portions of the belt, and the belt will therefore due to its pretension move a bit up and down with each tooth and gap. Some belt designs reduce this effect, but mostly it’s easier to use a pulley-like idler in the first place.
just like kuraasu said, that´s the reason why I’ve taken a pulley and not a bearing. And the effect is truly impressive.
I’m currently working on the improvement of the bracket with additional tensioner. At the same time I´m reconstructing the entire Y axis so that a GT2 can be used too.
Ah, thank you very much for the information, guys.
I already upgraded my printer to GT2 belts two weeks ago. Probably I will then replace the idler as well - at least as soon as you created a new idler mount with a tensioning mechanism
I have bought a piece of GT2 belt and some 16 teeth pulley’s.
But when i tryed to install it on the Y-axis , i noticed it won’t fit.
Because of the smaller diameter of the pully the belt hits the X-axis rod.
X-axis should be no problem but i don’t know if having 2 different belts and pully diameters is going to be a problem.
So i did not instal thet either.
as you can find in my description, i use a 20 tooth pulley. This is the smallest one you can use without complicated modifications.
The original T5 gearwheel has 15.9 mm diameter, the GT2(20) 12.7 mm diameter. Best fit should be a 25 tooth gear but i decide for the smaler one because the torque ratio and the resolution per steps are better. As i mentioned above the distance between x and y belt is very close
Theoretically you can use two different pulleys on one axis, the transmission pulley is always crucial. But is the difference between these two too big, you’ll get a problem due to the large angle. In this case, the belt side which is attached to the slide unit should be absolute aligned in horizontal position with the slide unit and it must be free to move in all directions at all times.
I had already designed the front site of the X feed unit with a tensionable pulley. However, I did not come around the X axis on the motor side. Thus, I was forced to modify the axles management, something like firefighter did (see german section RepRap forum):
The goal is to change the distance between the two axes so that the belts fit well. Hope i’ll be soon ready.
Hi guys,
I have just completed the modification to GT2 belts and pulleys with 16 teeth.
The printing quality has improved a lot, so I could recommend you to dare this too.
I choose the 16-teeth pulleys fort he reason of better torque. The usage of 16-teeth pulleys for the idlers as well makes the drives run smoother than using only bearings fort the idlers.
For this modification it is necessary to make some changes tot he locations aof motors and idlers. It is not complicated fort the x-axis; you just have to lower thex-motor position and the x-idler position for some millimeters. Solutions fort hat you find in different threads in this forum.
The best way to get the y-axis collison free with other parts ist o lift the complete y-axis drive up for an amount of 12 mm.
To check the situation and to be sure to have no collisions I made an OPEN SCAD file with all involved components, that lets you play with different parameters, so that you can check it all, before you disassemble your printer, after yo have printed the new components fort he modifications.
You will have to print the following parts:
1 y-motor holder
2 y-pulley holders
1 y-clip bottom (to fix the belt to the heatbbed adapter, ABS is to be preferred)
1 y-clip top (with GT2-profile)
1 x-motor holder
2 x-pulley holders (one hast o be mirrored
1 x-pulley holder base
I have made OPEN SCAD files for all those parts.
Sorry for the mistakes in text; my editor produced them due to auto correction, language setting “German”
I was not able to put the URL as well as pictures, wich you can watch in the Thingiverse post too.
Hey guys, i cant find where i configure my printer to the new steps/mm. When i try to do it in EEPROM configuration in Repetier-host the printer will move in SLOW MOTION, please help me, how do i configure the printer to the new GT2 20 tooth pulleys?
