Bear from Scratch w/ 310mm Z
None of these prints are necessarily awesome individually but I think they become awesome when combined with some other parts. Bear upgraded Prusa Mk3S from scratch with 310mm Z axis, and Bear Exxa with 10mm Z rods. Had to modify the Bear firmware and compile from source to get the tall Z to pass calibration, but it's alive and printing now.
Printed parts are Overture PETG, starry blue except for the extruder parts which are all black, with the fan shroud being black ASA. All printed on my stock Mk3S+
RE: Bear from Scratch w/ 310mm Z
Looks great!
RE: Bear from Scratch w/ 310mm Z
Thanks. Currently working on getting a Raspberry Pi and Pi camera set up so I can run Octoprint on it, and once I get it working I will set up the stock 3S+ the same way.
RE: Bear from Scratch w/ 310mm Z
This is excellent project, an upgrade as well as good aesthetic. I really like the color. I always wanted to do something like this, but my knowledge about the BOM is very limited. I can theoretically analyze how things work but I have no idea what part to use and where to get them. Also I think a project like this is best to use CAD to layout the plan, I can competently model but I never used the import library from standard parts. Do you get those from extension or provided by the manufacture? Do you use CNC machine to make some of the pars, or any other tools related to metal processing?
RE: Bear from Scratch w/ 310mm Z
So, there is an official Bear Upgrade kit which is made by LDO Motors, and sold by distributors world wide. Greg S. (the designer of the Bear Upgrade) gets a cut from the sales of this kit as far as I know, so buying one is a good way to support his work. Being open source, there's also a bunch of unofficial kits of varying degrees of fidelity to Greg's design. You can take one of these kits, a Prusa printer or kit, and add the Bear printed parts to make a standard Bear Upgraded Prusa which will have the same print envelope as the standard Prusa. There's also the Bear Exxa, which is an entirely separate mod consisting of a redesigned extruder and X-axis that's mostly made using the same components as the equivalent Prusa X-axis and extruder. It has some slight advantages over the standard Prusa units, and again, it's a separate and distinct mod from the Bear frame upgrade although you often see them together. You can use the Bear Exxa with the Prusa frame, and the Prusa X-axis and extruder with the Bear frame. Whatever you do, you probably aren't going to see any real differences in print quality, although I have heard that near the top of the Z limit the Bear frame will exhibit some improvement over the Prusa frame due to better rigidity.
Being a scratch build, I didn't use any of the available kits; it's entirely self sourced. It probably wasn't worth doing from a purely financial perspective, but in terms of jump starting my learning curve with regard to 3D printers in general, building it was probably the best thing I could have possibly done. I haven't done any tall prints with it yet, but compared to buying something like a Caribou 320 I am definitely money ahead.
I didn't do anything super sophisticated in terms of planning the project out. I bought a pair of LDO Z steppers that are 100mm taller than standard Prusa, and then I literally just added 100mm to the length of the vertical extrusions and the Z smooth rods when I cut them out. I used a mod which is available on Printables, for 10mm diameter Z smooth rods (standard is 8mm), which should improve the rigidity (important since I raised the height by 50%). The downside of that mod was that it locked me into using the Bear Exxa which in hindsight was a good thing.
The only "CNC" involved in the project was the use of a bog standard MK3S+ to print out the Bear parts. I rough cut the extrusions slightly overlength using a bandsaw, and then I milled the ends square and to length on my milling machine. I set up a sacrificial aluminum end stop at one end of the table, made a light cut with a 1/2" end mill and zeroed the digital readout there. Then with the DRO set to metric I dialed the X over for the length of each extrusion, and milled to length in the vise with a previously squared end against the sacrificial end stop. There was a little bit of deburring required using this method (more than if using a chop saw and/or belt sander) but it resulted in exact repeatable lengths.
The rest was mostly just following a combination of the Bear and Prusa assembly manuals, depending on which part of the printer I was working on. Modifying and recompiling the firmware for the added 100mm height was non-trivial but I had help from some of the other users on the Bear discord.
RE: Bear from Scratch w/ 310mm Z
please.
I have a Prusa i3 bear mk3s mk3s 459 z tall-3D printerCannot print beyond 210mm.
How can I change and recompile the firmware to add 100mm of height?
thank you
RE: Bear from Scratch w/ 310mm Z
you will need to modify and recompile the firmware...
or
Try Zaribo Firmware
Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Bear from Scratch w/ 310mm Z
thank you
I'll try running it.
RE: Bear from Scratch w/ 310mm Z
Been almost 2 years but modifying the firmware is more complicated than just changing the Z-max value and compiling. I don't remember enough of it to be of much help, sorry. There was some trial and error involved, and as I said above, help on the Bear discord from people more knowledgeable than I.
What might be a better idea, and more upgradeable going forward, is to get a raspberry pi, and install Klipper instead of the Prusa firmware. I have been told Klipper will run fine with the existing Einsy mainboard although it was recommended to be to reflash the bootloader because the Prusa one is buggy. But I haven't done this yet; I am still running my modified firmware and Octoprint.
RE: Bear from Scratch w/ 310mm Z
JoanTabb thank you very much.
I was able to print 310mm.
Although the home position of y was opposite, I was able to use it.
RE: Bear from Scratch w/ 310mm Z
Netpackrat thank you very much.
I would like to try.
RE: Bear from Scratch w/ 310mm Z
The home position of the Y axis depends upon which side of the belt, the motor is on, if you can swap the motor to the other side of the belt, the home position will be correct.
Alternatively, if you can turn the motor connector around that will reverse the motor. (If the plug is polarised, you can use a needle to release the connectors inside the shell, and re arrange them.
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Bear from Scratch w/ 310mm Z
Thank you JoanTabb.
I solved the problem by reversing the left and right motors.