Belt tensioner for Rostock Max

A place to talk about user-made mods and upgrades to their machines
Post Reply
gabrielk
Printmaster!
Posts: 49
Joined: Tue Feb 05, 2013 10:05 am

Belt tensioner for Rostock Max

Post by gabrielk » Tue Feb 19, 2013 8:14 pm

Since I don't know anything about pulleys, timming belts and stuff (rostock is my first project of this kind) I want to have better control over belt tension, So I managed to made my own belt tensioners which uses orginal not used holes of rostock. This gives me two things:
1. more accurate tensioning
2. leveling the pulley which helps keepping belt in the center. This helps to smooth moves, it changes when belt hits the wall.
Here are the pictures. As you can see I also stick teflon tape to reduce friction if belt try to hit the wall.
tensioner.jpg
tensioner-1.jpg
tensioner2.jpg

By using tensioners i can keep belts in the center on the top pulleys. The position in bottom ones and on the shaft is another story. There is more factors (position of the belt clamps, angles of two bottom pulleys, angle of the shaft ).

I hope this can help somebody. (STILL DON'T KNOW HOW MUCH TENSION BELTS SHOULD HAVE :) )

User avatar
daftscience
Printmaster!
Posts: 205
Joined: Sun Jan 13, 2013 12:37 pm

Re: Belt tensioner for Rostock Max

Post by daftscience » Wed Feb 20, 2013 5:31 am

I might give that a try today. I wish I could help with how much tension to set, but I'm not too sure either. I have it tight because i'm afraid of slipping.

User avatar
mhackney
ULTIMATE 3D JEDDI
Posts: 5412
Joined: Mon Mar 26, 2012 4:15 pm
Location: MA, USA
Contact:

Re: Belt tensioner for Rostock Max

Post by mhackney » Wed Feb 20, 2013 8:34 am

I've been using timing belts on CNC equipment and printers for awhile. I get my belts at sdp-si.com and they have a great reference library. Belt Tensioning is item #8. The MAX has GT2 2mm belts 6mm wide. You can get the details on pages 51 and 52. These are registration drive belts for positioning (bottom of page 51). That means you do want them on the tighter side to minimize backlash. Even the experts say "Tension values for these applications should bedetermined experimentally to confirm that desired performance characteristics have been achieved." But here is some guidance using this information:

Since the belt is confined in the extrusion slot, you won't be able to do a traditional deflection test by pushing on the belt. So I home the carriages and locate the mid point of the belt. Use something to reach in under the belt and pull it out - I use a big paper clip. Then I pull on the belt. Now, you have to use a little judgement. If you can pull the belt out 1/2" or more using a fair amount of force (roughly 6 pounds), it is too loose. If you can barely move it 1/8" it is way too tight. This is a loooong span so you should expect some deflection.

Sublime Layers - my blog on Musings and Experiments in 3D Printing Technology and Art

Start Here:
A Strategy for Successful (and Great) Prints

Strategies for Resolving Print Artifacts

The Eclectic Angler

User avatar
theverant
Printmaster!
Posts: 188
Joined: Sun Dec 30, 2012 1:55 pm
Location: Halifax, NS, Canada

Re: Belt tensioner for Rostock Max

Post by theverant » Wed Feb 20, 2013 6:33 pm

I've been thinking about this same thing, since I've been having issues getting things right regarding tension and centring. Looks good.

User avatar
cambo3d
ULTIMATE 3D JEDDI
Posts: 1058
Joined: Thu Feb 07, 2013 10:03 pm
Location: Florida

Re: Belt tensioner for Rostock Max

Post by cambo3d » Tue Mar 19, 2013 7:13 pm

can you tell me what you used to make these? parts numbers?

User avatar
Eaglezsoar
ULTIMATE 3D JEDDI
Posts: 7185
Joined: Sun Apr 01, 2012 5:26 pm

Re: Belt tensioner for Rostock Max

Post by Eaglezsoar » Tue Apr 09, 2013 5:24 pm

mhackney wrote:I've been using timing belts on CNC equipment and printers for awhile. I get my belts at sdp-si.com and they have a great reference library. Belt Tensioning is item #8. The MAX has GT2 2mm belts 6mm wide. You can get the details on pages 51 and 52. These are registration drive belts for positioning (bottom of page 51). That means you do want them on the tighter side to minimize backlash. Even the experts say "Tension values for these applications should bedetermined experimentally to confirm that desired performance characteristics have been achieved." But here is some guidance using this information:

Since the belt is confined in the extrusion slot, you won't be able to do a traditional deflection test by pushing on the belt. So I home the carriages and locate the mid point of the belt. Use something to reach in under the belt and pull it out - I use a big paper clip. Then I pull on the belt. Now, you have to use a little judgement. If you can pull the belt out 1/2" or more using a fair amount of force (roughly 6 pounds), it is too loose. If you can barely move it 1/8" it is way too tight. This is a loooong span so you should expect some deflection.

Do you have the part number for the belts on SDP-SI? I searched this board using Google like you taught me and could not find the part number. SDP-SI.com is the worlds worst web site for finding something if you don't have the
the exact part number you are screwed. Search for GT2 - nope. Search for 6mm belt - nope. Silly me, I actually thought a could find it on that site. Thanks for reading my rants.

Carl

Polygonhell
ULTIMATE 3D JEDDI
Posts: 2430
Joined: Mon Mar 26, 2012 1:44 pm
Location: Redmond WA

Re: Belt tensioner for Rostock Max

Post by Polygonhell » Tue Apr 09, 2013 5:40 pm

https://sdp-si.com/eStore/PartDetail.as ... roupID=343

You need about 6M for all 3 belts.
The secret on SDP-SI's site is to select Metric before searching for anything even vaguely metric

User avatar
Eaglezsoar
ULTIMATE 3D JEDDI
Posts: 7185
Joined: Sun Apr 01, 2012 5:26 pm

Re: Belt tensioner for Rostock Max

Post by Eaglezsoar » Tue Apr 09, 2013 5:44 pm

Thanks for the part number.

Carl

designfactore
Prints-a-lot
Posts: 26
Joined: Thu May 23, 2013 2:58 pm

Re: Belt tensioner for Rostock Max

Post by designfactore » Sun Jun 09, 2013 11:03 pm

Hey guys, they changed that part number on the belts, will this one work?

A 6Z16MC060 at
https://sdp-si.com/eStore/Catalog

User avatar
JohnStack
Printmaster!
Posts: 852
Joined: Thu Jan 03, 2013 7:07 pm
Location: Carlsbad, CA
Contact:

Re: Belt tensioner for Rostock Max

Post by JohnStack » Mon Jun 10, 2013 2:31 pm

I would buy this assembly (I'm not a machinist) if there was a 3rd party source. I just adjusted mine this morning. First time in about 50 prints.
Technologist, Maker, Willing to question conventional logic
http://dropc.am/p/KhiI1a

User avatar
dpmacri
Printmaster!
Posts: 319
Joined: Sat Aug 17, 2013 1:01 am
Location: Beaverton, OR, USA

Re: Belt tensioner for Rostock Max

Post by dpmacri » Thu Sep 05, 2013 2:56 pm

mhackney wrote:Since the belt is confined in the extrusion slot, you won't be able to do a traditional deflection test by pushing on the belt. So I home the carriages and locate the mid point of the belt. Use something to reach in under the belt and pull it out - I use a big paper clip. Then I pull on the belt. Now, you have to use a little judgement. If you can pull the belt out 1/2" or more using a fair amount of force (roughly 6 pounds), it is too loose. If you can barely move it 1/8" it is way too tight. This is a loooong span so you should expect some deflection.


I was trying to set the Z-height on my MAX last night (just got to that point in the manual) and after setting things in the EEPROM, when I homed again and then brought down to Z0, the head hit the bed. I had to take another .4mm off the height. So my thinking was that perhaps there's too much play in the belts (having never adjusted a belt before I wasn't sure how tight they should be. Searching found this thread. I followed the instruction above and realized that I can *easily* pull out 1/2" and without much force can get to 1 1/2". So obviously my belts are too loose :D

Does anyone agree that that would cause my Z Max Height calculation to change, due to slop/backlash?

User avatar
Jimustanguitar
ULTIMATE 3D JEDDI
Posts: 2631
Joined: Sun Mar 31, 2013 1:35 am
Location: Notre Dame area
Contact:

Re: Belt tensioner for Rostock Max

Post by Jimustanguitar » Thu Sep 05, 2013 3:11 pm

mhackney wrote:If you can pull the belt out 1/2" or more using a fair amount of force (roughly 6 pounds), it is too loose. If you can barely move it 1/8" it is way too tight. This is a loooong span so you should expect some deflection.


I usually get one belt exactly where I want it, and then I pluck it like a guitar string and just tension the other 2 belts until they play the same note :)

User avatar
dsnettleton
Printmaster!
Posts: 102
Joined: Fri Mar 22, 2013 11:09 am

Re: Belt tensioner for Rostock Max

Post by dsnettleton » Fri Sep 06, 2013 4:50 pm

Found this on Thingiverse.
http://www.thingiverse.com/thing:146815
I haven't tried it yet (though I plan to), but it looks like it would need a whole lot less hardware. :)
Trust me, sir. I'm a wizard.

edward
Printmaster!
Posts: 207
Joined: Mon Jun 03, 2013 8:55 am
Location: Fort Wayne, IN
Contact:

Re: Belt tensioner for Rostock Max

Post by edward » Fri Sep 06, 2013 5:20 pm

That's me :D

I modified barnett's design, found in this older thread here: viewtopic.php?f=54&t=1860

After taking some slack out of my belts by pulling them through a bit more, these really helped get them tight - and centered.
My Thingiverse profile: http://www.thingiverse.com/edwardh

Post Reply

Return to “Mods and Upgrades”