Fixing Pulley Innacuracy

[foehnsturm 969]

Hi Calum,

did you have a closer look at the z-axis coupler already?

I did today, after some hours of test printing and adjusting as recommended without much success. All higher parts more or less showed the z-screw pitch.

I have to admit, at least my z-axis coupler is Toys"R"us quality: nice surface, nice chamfers, 4 grub screws - but a 5 mm bore beyond good and evil.

Even with my shaky Chinese hobby lathe it took only a few minutes to make a better part. Well, I had the 5 mm and 8 mm reamers, which I originally bought for the pulleys.

Please Ultimaker, don't spoil such a clever machine design with crappy parts!

Markus

Before - after (corn canons for the kids)

 

[snowygrouch 1]

I just bought a big box of flexible 5to8mm couplers.

They are not quite as good as the last ones I got, but I will replace the Z coupler

with one and see what happens.

I think also stiffer Bedplate springs will help. My table just flies around like those play toys in the park

which consist of a seat and handes on a big spring...

But I have a horrible suspicion that this will all lead to the inevitable...complete replacement of the Z stage.

 

[lars86 42]

I just bought a big box of flexible 5to8mm couplers.

They are not quite as good as the last ones I got, but I will replace the Z coupler

with one and see what happens.

I think also stiffer Bedplate springs will help. My table just flies around like those play toys in the park

which consist of a seat and handes on a big spring...

But I have a horrible suspicion that this will all lead to the inevitable...complete replacement of the Z stage.

 

What needs to happen to stabilize the bed (cantilevered design aside), is to take out the XY lash, while still allowing some give in Z. I'm thinking about mounting Oilite bushings (like the 8mm ones) vertically in the bed itself. Then bolting stubby shafts on the platform to ride in those bushings, with springs placed on each shaft pushing the bed away. The shafts would be drilled and tapped on the top surface to allow a flanged bolt from the top to set height.

I'm almost done with a complete top end rebuild tonight. I completely redesigned the hot end, and print head. The head is printed and includes an integrated 40mm fan shroud, which ducts air though a custom made heat sink on the stainless steel up-tube. Also, added MoonCactus' XY blocks.

 

[snowygrouch 1]

I found that initially I had horrible friction with the "mooncactus" XY blocks. Which drove me nuts,

which was eventually traced to there being too much clamping on the XY bushes. Such that even three

little M3 screws were able to squash it enough to deform the bronze to clamp right onto the 8mm steel rods.

So had to spend some time reworking the 11mm bore on the XY blocks. Its much better now, but I think

that a clamp design is not ideal for these bushes. So will probably redesign the XY blocks to reuse

excellent belt tension concept but have original push fit design for bronze bushes.

I think we are wandering somewhat off track on this thread now...I suppose we ought to start a "New XY blocks" thread

in modifications and hacks...

C.

 

[lars86 42]

I found that initially I had horrible friction with the "mooncactus" XY blocks. Which drove me nuts,

which was eventually traced to there being too much clamping on the XY bushes. Such that even three

little M3 screws were able to squash it enough to deform the bronze to clamp right onto the 8mm steel rods.

So had to spend some time reworking the 11mm bore on the XY blocks. Its much better now, but I think

that a clamp design is not ideal for these bushes. So will probably redesign the XY blocks to reuse

excellent belt tension concept but have original push fit design for bronze bushes.

I think we are wandering somewhat off track on this thread now...I suppose we ought to start a "New XY blocks" thread

in modifications and hacks...

C.

Thank you for that insight! I was wondering where all that friction came from, but hadn't started tracking it down yet. Running the single clamp bolts totally loose, and the front 2 just snug seems much better. Time for a redesign!

 

[reprogue 0]

Hi @foehnsturm,

I'd also like to order a set, if a second batch is going to be made.

Thanks.

 

[antiklesys 3]

Hi I would be interested in ordering a set of pulleys too.

 

[foehnsturm 969]

Hi guys,

I will order another batch in the second half of July.

Prices are only slightly changed (mainly due to PayPal's inscrutable fee policy).

In detail:

 

• [*]20 teeth, effective circular diameter same as original pulleys

[*]dimensions: 17 mm (outer diameter) x 16.7 mm

[*]8H7 or 5H7 center bore

[*]two m4 threads with grub screws

[*]vibratory deburred

 

Prices:

 

• [*]Set for Standard Ultimakers (10 x 8 mm, 2 x 5 mm): 70 € / 94 US$

[*]Set for direct drive Ultimakers (8 x 8mm) 47 € / 63 US$

 

VAT and customs duty not included.

Payment via bank transfer or Paypal

 

Shipping:

Deutsche Post, insured letter

within Germany: 7 €

anywhere else: 12 € / 16 US$

 

Binding orders:

MakingZone (Elbozo), TZ Advantage, mpoint, Take 1, JonnyBischof, Urban (2), hreedijk, Piranha, Sserpent, Reprogue, scottvader, amano, mr_clark, Nicolinux

Pre-orders so far from:

Antiklesys

Please send me a message with your detailed order, address and email.

 

Order-DEADLINE: July 15th

 

Markus

 

[snowygrouch 1]

Sounds great, I think I have enough now so will not order any more for myself.

Only point to just mention is that a small letter on the tolerance prefix denotes a tolerance on

a shaft...not a bore. Its a capital letter for a bore tolerance...(difference is that if you

order some more on a h7 shaft tolerance they will all come out -15>0 micron instead of 0>+15micron which

would be written H7).

Just checking !

C.

 

[foehnsturm 969]

Thanks Calum! I corrected it. (recently learned the logik behind tolerances but still mixing up the upper/lower case)

 

[makingzone 2]

Is the 2nd batch still available ?

 

[jonnybischof 60]

Hi Markus

I'd like to order a full set for standard ultimaker, too!

Don't have my UM yet but I want to already incorporate as many improvements as possible from the beginning...

Greetings from Switzerland

Jonny

[urban 0]

Hi Markus

I also would like to order 2 full sets for my standart ultimaker and my larger one (which is in cad stage)

Best Urban

 

[foehnsturm 969]

I placed the order yesterday.

 

[joergen 2]

I finally got around to install my new pulleys 3 days ago, and parts are looking much nicer now. I believe the print dimensional accuracy has improved a great deal for me, parts are fitting now a bit better together than before.

so, thank you for making those amazing new pulleys. (anybody need a set of used, slightly wobbly pulleys?)

 

[nick-foley 5]

I just built up a machine using GT2 belts and pulleys (sourced from SDP-SI and adafruit) and am seeing some big improvements too. The print quality is definitely higher, though some of that is likely due to the improved hotend and not just the pulleys. Regardless, moving the head by hand is much smoother, and the entire machine is much quieter in operation. I don't think this is too much a factor of MXL vs. GT2 - I think it's mostly just that the GT2 pulleys are higher quality and not crazy eccentric like the standard UM pulleys.

I do like the firmware elegance of GT2 pulleys requiring exactly 80 steps per MM though, vs 79.XXXXXXXXX or whatever it was for MXL. With no adjustments, parts were coming off within .1mm of accuracy.

 

[amano 0]

foehnsturm, hope you've received my message!?

 

[foehnsturm 969]

@amano,

yes, I will send messages when I know the delivery date, but I keep the list of orders on page 7 up to date ( easy to overlook, I know).

Markus

 

[Nicolinux 288]

Hi Markus,

I know I am too late for the second batch - I just received my Ultimaker a few days ago. But if for any reason you have a full set left (standard) - I am in.

I am still building my printer and got stuck while aligning the x/y axis. I refused to accept that the cause for my problem (variable resistance while moving in one direction) could be those pulleys. For the y axis it is so bad that I have to use much force to reach the edge. I guess I installed the worst pulley from my set on the same rod :/

Here is my original thread - thanks to Nick for pointing me here

http://umforum.ultimaker.com/index.php?/topic/2589-axis-alignment-problem

Stefan

[joergen 2]

Hi Markus,

I know I am too late for the second batch - I just received my Ultimaker a few days ago. But if for any reason you have a full set left (standard) - I am in.

I am still building my printer and got stuck while aligning the x/y axis. I refused to accept that the cause for my problem (variable resistance while moving in one direction) could be those pulleys. For the y axis it is so bad that I have to use much force to reach the edge. I guess I installed the worst pulley from my set on the same rod :/

Here is my original thread - thanks to Nick for pointing me here

http://umforum.ultimaker.com/index.php?/topic/2589-axis-alignment-problem

Stefan

 

This is somewhat off topic in this thread, feel free to open a new thread.

If you cant push the gantry across, your axis are not square, or (very rarely) your rods are bend (you can test this by rolling them across a flat surface), other than that, properly square your system, and it will move nicely.

[Nicolinux 288]

Thanks for the hints Joergen. I updated my initial post.

http://umforum.ultimaker.com/index.php?/topic/2589-axis-alignment-problem/?p=18566&do=findComment&comment=18566

[foehnsturm 969]

Hi all,

The pulleys will arrive next week - but we are on holidays from August 10 to 24.

I will send the paying information and do the shipping immediately afterwards.

Markus

 

[makingzone 2]

Hi all,

The pulleys will arrive next week - but we are on holidays from August 10 to 24.

I will send the paying information and do the shipping immediately afterwards.

Markus

 

Yeahhhh !!!!

 

[LePaul 321]

I just ordered my kit and I am wondering if the kit will include better pulleys?

Whom should I contact to replace them with the improved ones? At what cost?

Thanks!

 

[snowygrouch 1]

You will not get better pullies in the standard kit (yet).

The other info you want can be found by reading the thread from the beginning.