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Fixing Pulley Innacuracy


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Posted · Fixing Pulley Innacuracy

Hi folks,

All paid orders have been shipped today via Deutsche Post "Wertbrief" (insured letter). This includes the Aussie shipment. The US shipment is currently waiting for the last two payments to arrive.

I would like to send out things until this Friday, as we are on holidays next week. Any pending orders have to be handled thereafter.

Markus

 

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    Posted · Fixing Pulley Innacuracy

     

    Hello,

    If it is still possible, I also would like to pre-order a set of pulleys for the Ultimaker.

    I would like to order a full set : 8 x 8mmm and 2 x 5mm.

    I have Paypal, so please let me know when it's time to make the payment for the order.

    Thanks for your efforts !

     

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    Posted · Fixing Pulley Innacuracy

    Out of interest, what sort of configuration involves 8x 8mm and 2x 5mm pulleys? I can understand direct drive using 8x 8mm pulleys or the stock configuration using 10x 8mm and 2x 5mm pulleys, am I missing something?

     

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    Posted · Fixing Pulley Innacuracy

    Actually, sign me in for 10 x 8 and 2 x 5 mm pulleys.

    A full set pulleys : 10 x 8 and 2 x 5 mm !! :)

     

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    Posted · Fixing Pulley Innacuracy

    Hi Rob,

    You are absolutely right. I mixed up numbers when I was writing that post (and converting to direct drive at the same time). Fixed it now.

    Markus

     

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    Posted · Fixing Pulley Innacuracy

    US shipping complete.

    UltiFan, Nick,

    I'm sorry. I will put you down for the next batch if you like.

     

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    Posted · Fixing Pulley Innacuracy

    Yes, please let me know if you do a second batch. Thanks anyway!

     

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    Posted · Fixing Pulley Innacuracy

    Same for me.

    Thanks !

     

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    Posted · Fixing Pulley Innacuracy

    I've received my new pulleys today. Thank you, foehn! Still have to install them but they make a very nice and professional appearance already.

     

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    Posted · Fixing Pulley Innacuracy

    All paid orders, including the US shipping are on the way.

     

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    Posted · Fixing Pulley Innacuracy

    Count me in for the next batch!

    Currently rebuilding my UM within a aluminium frame, one of the missing parts are the pulley's!.

    I'd like a full set (10x8, 2x5).

    Regards,

    Harold

     

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    Posted · Fixing Pulley Innacuracy

    Just found this post, if it is not too late - I need complete set of pulleys please!

    Best rgards, Dmitry

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    Posted · Fixing Pulley Innacuracy

    This is slightly off topic (or back to the original topic of this thread), but has anyone tried and successfully implemented the GT2 belts and pulleys from SDS/SI? This seems to be the correct part for the 8mm bore pulleys:

    https://sdp-si.com/eStore/Catalog/PartNumber/A%206Z51M036DF0608

    My concern is that the overall diameter of the pulley is too large to fit without colliding with the other pulleys, since it appears very close with the original design.

     

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    Posted · Fixing Pulley Innacuracy

    Installed my pulleys today. Man, what an incredible improvement in accuracy. Great stuff!

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    Posted · Fixing Pulley Innacuracy

    Pulleys arrived today, and they will go out tomorrow via USPS (simple padded envelope)

     

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    Posted · Fixing Pulley Innacuracy

    Excellent news! Thanks for facilitating this, Joergen. Let me know how to pay you for the postage etc.

     

    Pulleys arrived today, and they will go out tomorrow via USPS (simple padded envelope)

     

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    Posted · Fixing Pulley Innacuracy

    Argh, so bummed I missed this order! Every time I hear the vvvvVVVVVvvvvVVVVVVvvvvvVVVVVVvvvvvvVVVVVvvvv of my Ultimaker I think about these.

    Very curious to hear how these things improve operation. It would be amazing to get a before/after print comparison photo.

     

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    Posted · Fixing Pulley Innacuracy

    I received my pulleys earlier this week and will try to install them today together with fresh belts (they are spare parts from UM; my current ones are two years old and a bit worn) and a new Thermocouple board also from UM (my old one is a bit off in temperature).

    My question to those of you who has already upgraded to the new pulleys:

    - How long time did it take and exactly whats steps are needed to do this?

    I would guess that parts of the steps on the Ultimaker wiki assembly pages would need to be followed in reverse, but I also suspect that it might not be as simple as that?

    I have an older (about two years) Ultimaker with the 8mm rods for the XY head cross, but I guess that doesn't really affect the pulley upgrade?

    I'm also thinking about making (with my lathe) a small centering hole on the end of each steel rods, so that you could mount a modified screw in through the rod caps like described in the comments to this:

    http://www.thingiverse.com/thing:54075

    This way it would act like "turning between centers" in a metal lathe setup.

    However, I'm not sure if it's worth all the work that this would entail, what do you think??

     

    Cheers,

    Daniel

     

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    Posted · Fixing Pulley Innacuracy

    I would not use the cap screws in an attempt to locate the rods. That's great on a lathe, when the live centers are perfectly coaxial, and supported by bearings. In this case, the screws are located by the end caps which can shift relative to the rod axis, and are fixed from turning. The rod bearings are located nicely by the laser cut frame. You stand to gain nothing, but could induce extra friction/bind.

    On mine, I have printed end caps, with pointed screws. I run them set for just a slight bit of lash (no preload), and it is a great combo of low friction and good location.

     

    I received my pulleys earlier this week and will try to install them today together with fresh belts (they are spare parts from UM; my current ones are two years old and a bit worn) and a new Thermocouple board also from UM (my old one is a bit off in temperature).

    My question to those of you who has already upgraded to the new pulleys:

    - How long time did it take and exactly whats steps are needed to do this?

    I would guess that parts of the steps on the Ultimaker wiki assembly pages would need to be followed in reverse, but I also suspect that it might not be as simple as that?

    I have an older (about two years) Ultimaker with the 8mm rods for the XY head cross, but I guess that doesn't really affect the pulley upgrade?

    I'm also thinking about making (with my lathe) a small centering hole on the end of each steel rods, so that you could mount a modified screw in through the rod caps like described in the comments to this:

    http://www.thingiverse.com/thing:54075

    This way it would act like "turning between centers" in a metal lathe setup.

    However, I'm not sure if it's worth all the work that this would entail, what do you think??

     

    Cheers,

    Daniel

     

     

     

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    Posted · Fixing Pulley Innacuracy

    I would not use the cap screws in an attempt to locate the rods. That's great on a lathe, when the live centers are perfectly coaxial, and supported by bearings. In this case, the screws are located by the end caps which can shift relative to the rod axis, and are fixed from turning. The rod bearings are located nicely by the laser cut frame. You stand to gain nothing, but could induce extra friction/bind.

     

    I'm not convinced by this argument - 1) though not as great as a live center, a dead center works fine on a lathe for most operations and I see no reason it wouldn't improve things here, and 2) If the bearings are adequately aligned by the laser-cut frame, I see no reason that the endcaps couldn't also be adequately aligned, particularly if they are a 3D printed part with a tighter fit than the laser cut caps.

    This is definitely something I would do if I had easy access to a metal lathe. It's unclear if Daniel meant drilling an actual hole, or just an V- shaped indentation with the tip of a drillbit. Obviously a full hole won't work so well, but I think a V-profiled cut with an angle wider than the bevel angle of the pointed cap screw could only be an improvement.

     

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    Posted · Fixing Pulley Innacuracy

    I would only add 2 comments:

    1) If you use direct drive setup, the flexible couplers align 2 of the 8mm axis for you anyway.

    2) The other 2 can be fixed axially with these:

    http://www.conrad.de/ce/de/product/223735/Stellring-Sortiment

    I do not think there is enough room for these lockrings if you dont have direct drive setup.

     

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    Posted · Fixing Pulley Innacuracy

    I'm not convinced by this argument - 1) though not as great as a live center, a dead center works fine on a lathe for most operations and I see no reason it wouldn't improve things here, and 2) If the bearings are adequately aligned by the laser-cut frame, I see no reason that the endcaps couldn't also be adequately aligned, particularly if they are a 3D printed part with a tighter fit than the laser cut caps.

    This is definitely something I would do if I had easy access to a metal lathe. It's unclear if Daniel meant drilling an actual hole, or just an V- shaped indentation with the tip of a drillbit. Obviously a full hole won't work so well, but I think a V-profiled cut with an angle wider than the bevel angle of the pointed cap screw could only be an improvement.

     

    Your argument doesn't make sense to me.

     

    You claim "a dead center works fine on a lathe for most operations", like it proves that a dead center is better in this specific case we are looking at. The reason a dead center "works fine", is because a lathe has a torquey drive motor that can overcome the dead center's parasitic friction. We are trying to remove all possible friction throughout the carriage drive assembly, in search of better quality of motion. The bearings that the shafts ride on are not only low friction, but locate the rods well in the normal plane. Adding a dead center on top of them adds unnecessary friction, and can offer no help in the already located rods. At best, it can mirror the location, and at worst it could try to constrain the rods with a slight shift, inducing bind. Yes the cap mounting holes are laser cut, but an M3 bolt's fit in these holes is nowhere near the fit between the bearing and case (by design).

     

    Take it as you will. I'm just a mechanical engineer that designs and programs machining strategies for a high-tech manufacturing firm (big CNC mill-turn rigs)... what do I know, hahaha

     

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