belt tensioner

[ppope357 0]

Hi

I'm building my machine and the x and y axis pulleys are loose, even after tightening the belt tensioning screws. I need to get the pulleys to the right tension, but am unable to do so. Does anyone have any suggestions as to how I can sort this out, get the proper tension on the pulley belts and get on with my build?

I've seen a few designs for printed belt tensioners on thingiverse, but they all require a 3d printer to make, which I am in the process of building - so that option is out. I also saw a really cunning fix with a clothes peg spring, but having tried this, my build envelope will be significantly reduced - so I don't want to go down that route either.

Anyway, I'm getting a bit frustrated now because I have a printer kit, but I can't complete it because I cant move past this stage and get the thing finished - so any help or suggestions would be much appreciated.

Thanks!

[IRobertI 517]

Your build envelope will not be affected if you install the spring in the correct location. For example, to tension the belt closest to you when facing the machine; move the head to the left or right end stop and then install the tensioner on the opposite side as close as possible to the pulley. With the tensioner installed in this location you will be able to move the print head as normal and it wont affect your build envelope at all.

Personally I used piano/music wire to create tensioners which worked quite nicely but I ended up replacing them with these:

http://www.thingiverse.com/thing:17058

 

[ppope357 0]

hi

many thanks for the quick reply. I've tried the method you mentioned, using the metal spring from a clothes peg. It seems to be working - I think I'll need to tinker a bit to get the tension levels just right, but that will have to wait for tomorrow. also I feel a bit stupid for not realising I could fit the tensioner to the longer section of pulley

Anyway, once the printer is up and running I will print the part you have linked to. many thanks!

[hedis 0]

I'm also using thing:17058. They are great!

[tjeb 0]

For other people having the same problems; loose belts still allow you to print, but at a lesser quality (print a small circle and keep it to compare with when you do have your tension right ). Adding them later is not really hard.

I tried

http://www.thingiverse.com/thing:19818

and they work great; I needed 1 on each of my X-axes, and 2 on my Y's (...). Fitting two with the normal screws is a tight match, so I'm thinking of getting longer ones, but it does work with the standard screws.

[approx 0]

 

http://www.thingiverse.com/thing:17058

has been working great for me as well..

[futurejames 0]

but I now have

http://www.thingiverse.com/thing:19818

and they work great; I needed 1 on each of my X-axes, and 2 on my Y's (...). Fitting two with the normal screws is a tight match, so I'm thinking of getting longer ones, but it does work with the standard screws.

Wow, 2 on your Y's? Did you put one on each side? I didn't have enough tension in my X's and added a small piece of wood between the tensioner and the belt. But I'd like to know how you did it, it sounds like a much cleaner solution.

[tjeb 0]

but I now have

http://www.thingiverse.com/thing:19818

and they work great; I needed 1 on each of my X-axes, and 2 on my Y's (...). Fitting two with the normal screws is a tight match, so I'm thinking of getting longer ones, but it does work with the standard screws.

Wow, 2 on your Y's? Did you put one on each side? I didn't have enough tension in my X's and added a small piece of wood between the tensioner and the belt. But I'd like to know how you did it, it sounds like a much cleaner solution.

Yeah, one on each side; it requires that you do completely pull out the 3 screws, and fitting the nuts back on is tricky since the screws are just barely long enough to make it (and they only go half way into the nuts now). Next time i'm at the shop I'm gonna see if I can find slightly longer screws, but for now it seems to hang on just fine.

In effect this does the same as thing:17058 I guess, with the slight advantage of being adjustable while mounted and being held by the screws (but, again, I have not tried 17058, i found these earlier and they did the trick for me). The disadvantage of course is that you'll lose your tension if the screws get loose, so for important prints you might want to check and tighten them

[IRobertI 517]

You could use one of those washers that I've forgotten the name of right now... These guys:

http://image.made-in-china.com/4f0j00zv ... 798-V-.jpg

That should bite in nicely into the plastic and make it stay in place.

[cgp 0]

I made some simple E shaped tensioners that help some but are too small. The belts are still not tight enough and still getting oblong holes. Has anyone tried the wave tensioners by Gijs? I just printed some in PLA but a little worried about strength. I actually modified by adding a bracing element along the length of the concave side. We'll see if they hold.