Do you have a link to the part you used as a replacement?
I used these from mcmaster carr. http://www.mcmaster.com/#standard-linear-bearings/=nnimgb
but at $20 each they are not cheap.
There are several seller of cheap ones out there. just search for LM10UU bearings. I ordered these: http://www.ebay.com/itm/12pcs-LM10UU-10mm-Linear-Ball-Bearing-Bush-Bushing-/111015105791?pt=BI_Heavy_Equipment_Parts&hash=item19d90414ff for the machine I am building for home. $12.50 for 12 is super cheap…hopefully they are OK.
Aren’t those LM10UU bearings a lot noisier than the IGUS ones? I remember seeing a video comparison. Considering how much the IGUS sell, I’m guessing the Lulzbot guys went with them to reduce the noise.
Some people are also printing them in PLA with apparently good results.
Is there a link somewhere that explains what hysteresis is, in layman terms? I have no machine design background, and the Wikipedia page about it may as well be written in Mandarin.
Ya, we went with the igus LM10UU bushings primarily because of noise.
Hysteresis is the type of motion you get when you have backlash and friction…basically, hysteresis is caused by a combination of backlash and other things, though backlash is usually the main cause.
lets say you command the X axis to move from 10mm to 100mm and you put an indicator on it and zero it out. Now you command the X axis to move to 190mm. and then you command it back to 100mm. The indicator will no longer be at exactly Zero, and the number you get (lets say you get 1mm) is the actual hysteresis. Backlash is one of the main causes of Hysteresis, but it is not the only one. Loose bearings, and high friction in the linear guides can also contribute to it.
another way to visualize hysterysis is to go out to your car, near the front wheel and push down on it to cmpress the spring and then slowly let it come back up. Measure the distance from the bottom of the car to the ground. Now pull up on the car and then slowly let it settle back down and re-measure. the difference in the measurement is the hysteresis.
Hysteresis is a general term that can apply to MANY things, not just mechanical systems. There is magnetic hysteresis, and electrical, as well as others I am sure.
there is more noise with the ball bearings, but I find the noise of the stepper motors to be louder…especially during rapid moves, so it seems to be a non-issue overall.
I hope lulzbot re-looks at the ball bearings, or at least gets some tighter IGUS style bearings in the future.
Thanks for the hysteresis explanation!
I’m printing with a wrench on my bed to solve loose bearings on the y-axis. Adjusting them didn’t help
Have you tested those cheap LM10UU bearings? I don’t want to drop $50 on these bearings from the lulzbot store if I can pay $20 for something that works. Thanks.
McMastercarr sells ball bearing that work well for about 20$ a piece (xaxis you will need 3) they are a necessity if you are going to attempt dual extrusion
What’s the Rockwell on the 10mm shafts that Lulzbot supplies on the TAZ?
I have created a new bearing holder for the Taz that might solve this issue. I am still testing it but seems good so far. Check it out and let me know if i need to make any modifications to it.
It uses the Misumi part SHBZ10-25 for the bushing.
Better late than never…
There’s no Rockwell, apparently they’re Misumi SSFHR10-500 stainless steel rotary shafts - that is, according to the TAZ BOM available here: http://downloads.lulzbot.com/lulzbot/TAZ/hardware/
Misumi product page: http://us.misumi-ec.com/vona2/detail/110300086920/
Yeah there is. The 4137 alloy shafting is 30-35Rc, the 1045 shafting could be similar depending on how it was heat treated.
The 304 CRES is dead soft. Most likely fine with plastic bearings but with hard bearings you would be better off with shafting that is 55-58 Rc.
As I said already, the Misumi part number shown in the BOM is SSFHR10-500.
If you look again at that Misumi page, SSFR stands for 304 Stainless Steel. The table lists “-” as surface treatment. Can we assume “-” means none?
To which I answered, if we are to believe the TAZ BOM, there is none.
I have not found any hardness (Rc or otherwise) information for the smooth rods.
Well the ones that lulzbot uses (Misumi part number: SSFHR10-500) on there printers has like no documented HRC however. I just bought these rods and replaced the stock ones with these…
The Rc may not be listed but there is a hardness for 304. Typically depending on the alloy it will be 25-37 HRC. With plastic bushings the stock rods would be fine. With ball bearings maybe not so good.
Well I got the answer.
Subject: Re: FWD:Inquiry via website [About products]
can you tell me what the HRC is for product SSFHR10-500? It is not documented on the site that I can see/tell.
The material on this shaft will be standard non-hardened 304 stainless steel, its hardness is found in Metals Handbook. According to literature, its hardness is 88 HRB, which is substantially less than hardness ratings in the HRC scale.
FA Standard Components Engineer
MISUMI USA, INC.
88HRB converts to an Rc of 9.