Linear Bearing Help

Hi. I recently purchased a used Monopricer Maker Select and I am starting the standard upgrades. I purchased a new Y carriage plate and starting searching for some quality LM8LUU bearings. Misumi's are a bit more than I want spend and after that most bearings I have seen for sale seem to be generic chinese bearings. I found Vxb sells them for 9.99 a piece. I have had good luck Vxb bearing in the past, I use them in my wood working machines. The only thing that has me curious is that the Vxb LM8LUU bearings say that they have 4 ball circuits. I assume this means that there will be four points of contact with the smooth rod. Is this adequate for 3d printers or do I need to keep looking. Also if anybody has a recommendation for a quality bearing that would be a great help.

I think 4 rows of ball bearings is pretty standard.
I guess you dould go down to three for really cheap bearings, but never used many or taken any apart.

But yeah 4 is fine.

The other thing to bear in mind is that you probably do not need to do any of the 'standard' upgrades.

Before changing any original hardware - actually use the machine - fairly extensively - ad see if there are any areas that actually NEED changing.

In my experinece most printers run fine with original parts and the upgardes make little or no difference.

You need to bear in mind that people on facebook groups and youtube - tend to be people who will tinker and change things - regardless of whether they need to or not.

Hey thanks for replying, I had kinda of given up hope and was getting ready to tear into the printer. The printer has been turning out some good prints except for some horrible ringing. I wanted to do these upgrades to tighten up the machine and hopefully get some high quality prints. My first printer is a davinci duo which is all brass bushings so I have had no experience with linear bearings. I thought 4 rows of balls to be too little and would cause excessive wear and unwanted motion. To my mind 6 or 8 rows seemed to be more precise, but if 4 rows is standard I will go ahead and order the Vxb's.

For ringing you need to tune acceleration and junction deviation / jerk settings. But that is only gonna get you so far. You need bearings with a light preload that are still smooth and real precision bearings like that cost money. Loose bearings contribute heavily to ringing because when the stepper motor stops the carriage just wants to keep going. Sure it is a little more efficient on the power bill absolutely no load on the steppers but at the cost of salmon skin on the surface of your prints. If you don't like the price of your Misumi lm8luu bearings you would absolutely hate the correct solution for your problem from Motion Constrained. But on the cheaper end maybe you should give the polymer bushings a try. They have light preload on them and cant be any worse than the loose 4 point of contact or less Chinese bearings out there. no? https://www.vxb.com/Low-noise-Linear...BoCnAMQAvD_BwE

Oh wait, did you say Monoprice? Well then you wont be tuning acceleration and junction deviation or jerk or enabling lin_advance. For that you will first need an open source mainboard that will run Marlin firmware so you can tune those things. I think with the monoprice stuff you are limited to settings in the slicer. But it is all good, tech has come a long way in a short time as it always does and the boards of the day that support the marlin firmware all come with fast n spiffy 32 bit processors, they all support silent drivers so you aren't tortured by the sounds of your robot. And they come with wifi options and some even with direct support for a raspberry pi. The newer boards all feature inputs for filament runout detection, power off after print finishes relays, and outputs for neopixel. And what's better is some of these companies are making these boards to be a drop in solution for the cheap printers that nobody would put money into. And so you can get a 32 bit mainboard complete with 4 inbuilt tmc2209 UART drivers for under $40. And it can run the latest version of Marlin. Which is currently 2.0.6.1. And then you can just search Youtube for tutorials on how to tune and in order, E-steps, speed, acceleration, extrusion multiplier, LIN_ADVANCE, and junction deviation/ jerk setting from Chris Riley or Teaching Tech or Tom Salanderer. The little powerhouse is right here: https://www.biqu.equipment/collectio...rt-for-ender-3

I have been using prusa slicer through repetier on my davinci for a year and half so I have some experience slicer tuning. I started using cura for this new printer and it may take a bit to get used to it. In the future I will probably upgrade the board but right now I want to try flashing a new firmware on stock board though from what I understand once you flash a bootloader there isnt enough room left for a full repetier install. So I might try a custom build, I at least want thermal overun protection. As for bearings its tough to decide half of the articles I have read say that drylin are the way to go and half say say they are garbage stick with ball type. I suppose I should try both.

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Originally Posted by AutoWiz

Oh wait, did you say Monoprice? Well then you wont be tuning acceleration and junction deviation or jerk or enabling lin_advance. For that you will first need an open source mainboard that will run Marlin firmware so you can tune those things. I think with the monoprice stuff you are limited to settings in the slicer. But it is all good, tech has come a long way in a short time as it always does and the boards of the day that support the marlin firmware all come with fast n spiffy 32 bit processors, they all support silent drivers so you aren't tortured by the sounds of your robot. And they come with wifi options and some even with direct support for a raspberry pi. The newer boards all feature inputs for filament runout detection, power off after print finishes relays, and outputs for neopixel. And what's better is some of these companies are making these boards to be a drop in solution for the cheap printers that nobody would put money into. And so you can get a 32 bit mainboard complete with 4 inbuilt tmc2209 UART drivers for under $40. And it can run the latest version of Marlin. Which is currently 2.0.6.1. And then you can just search Youtube for tutorials on how to tune and in order, E-steps, speed, acceleration, extrusion multiplier, LIN_ADVANCE, and junction deviation/ jerk setting from Chris Riley or Teaching Tech or Tom Salanderer.

The little powerhouse is right here: https://www.biqu.equipment/collectio...rt-for-ender-3

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It's NOT a monoprice printer - rthe maker select is actually a wanhao i3 duplicator with a different badge. NOT a malayan.
So should have decent board and open source parts.
Wanhao are a quality company.
I'm presuming that these days they mostly make printers for other people - you don't seem to see their machines on amazon any more.

Even still the Melzi boards have been around since 2012 or earlier. They are not exactly better.