On the MK3 the standard mounting is with M3x10mm bolts rather than 12mm, and no washers. This means while the rear of the motor makes good contact with the mount, the front furthest from the aluminium extrusions is far from flush.

It wasn't anything I had any problem figuring out, but towards the end of the build the manual gets a little bit rougher around the edges. The biggest thing is that it tells you to attach the Z-tops which then prevents you from being able to insert teenuts for mounting the PSU & Rambo case. Like I said, pretty minor as it's easy to figure out, but seemed worth noting. (I did a MK2.5 full upgrade).

1. Improve 96/116mm building guide :
   • add vslot tab to ease with alignment
   • make it thicker
   • improve manual to give a tip on how to improve the part (increasing extrusion multiplier to get part bigger and then file it)
2. Add a guide to align Y axis rods

In the parts list:
1x M3 bolt (from the original PSU lower mount)

and in in assembly steps:
Add M3 bolt into the psu_lower_mount (figure 15.3)

Figure 15.3 correctly calls it a nut.

This will improve stability when printed with difficult/high temp filament. Will also make the surface of the rod a bit better. The back will need to be thicker to help with print stability.

https://github.com/gregsaun/prusa_i3_bear_upgrade/blob/master/full_upgrade/for_mk2.5/manual/assembly_instructions/step18.md

Currently it says to follow the MK2S instructions for assembly, but there are some extra cables to connect as described in manual.prusa3d.com/Guide/6.+Electronics/573?lang=en

https://www.facebook.com/photo.php?fbid=1737186839633533&set=gm.828999217284561&type=3&theater&ifg=1

Issue from adam6666 :

Hello Greg
There is a slight issue which I am facing. My printer is complete but during calibration, it shows left front calibration point can't be reached. Although when I check it manually, the pinda probe is exactly in the center of it. Please advise

The extrusion of the z-axis is not covered by end caps.

Suggestion: add a pair of end caps

• BOM: Add 1x pair of end caps, add 4x set screws
• add instructions to step 12 (at least for MK3)

I printed with adobe acrobat reader with real size, which print the size of the paper (letter in my case) intead of the whole sketch, as the result of some of the distances doubled(center of the aluminum extrusion with the edge of the z frame, which measures 120mm instead of 60mm and 40 mm instead of 20mm). Any help on this?
Thanks

On the front y-rod mounts you cannot use zip ties as the ”head” hits the bed

Found in the comments here :
https://www.facebook.com/photo.php?fbid=1737186839633533&set=gm.828999217284561&type=3&theater&ifg=1

I always search for the link of the optional printed parts (/optional_parts.md) under: "half_upgrade/manual/bom.md" or "half_upgrade/manual/print_settings.md" . However it is first listed quite far back in step 4. "Preflight Check" . It appears intuitive and reasonable to me, to give the link also together with the standard printed parts in the manual steps mentioned above.

Update: I also noticed that in the half upgrade's BOM and list of printed parts, the quantitiy of the end caps is given with 2. However there are 4 corners and in the assembly instructions step 13 there are 4 end caps required. Maybe the intention was to print two times the stl containing 2 caps. However it is somewhat unclear. Maybe a stl with all 4 caps in it is better.

Cheers

I noticed an issues in the MK3 assembly instructions with regards to the y-motor mount:
Step 3.2: 2x tee nuts are inserted in the same slot. Later on the y-motor will be installed here, see step 8.2

However, the y-motor mount in the STL uses two nuts in two slots on the same side:

Option 1: instructions are outdated

• add 3rd tee nut
• modify fig 8.2 to depict current mount

Option 2: mount is outdated

• update STL

In step 4.1 it is instructed to put 4x black corners on.
However, the tee nuts on the 331 cm extrusions cannot be added without taking everything apart again.

Option 1:
The tee nuts have to be added before step 2.5

Option 2:
Add drop-in tee nuts to the BOM. Those can be added after the fact.

I've seen that you plan to cut everything yourself. Sometimes this and openbuilds (due to taxes) is not an option, so maybe it makes sense to list options where you can order the pieces pre-cut. For Germany good sources are:
http://www.motedis.com
http://kritec-gmbh.de

Hi his beautiful compliment project continue and I'm here better with her !!

I bought all the prices for assembling the Y axis ...

I have some questions:

the original MK2S pria fit the 100mm Y axis instead of its 110mm V-Slot design and 185mm later, its 195mm V-Slot design ever? Bearing Y bearings may have length problems

excuse my English to use the translator

The BOM https://github.com/gregsaun/prusa_i3_bear_upgrade/blob/master/full_upgrade/for_mk2.5/manual/bom.md
lists quantities and links for Tee-nuts and Low Profile M5 screws for (25pce pack) but it appears that the store now offers only (10pce pack).

For example, for the Tee-nuts: the link in the BOM is http://openbuildspartstore.com/tee-nuts-25-pack/
but this is redirected by the store to http://openbuildspartstore.com/tee-nuts-10-pack/
The quantity in the BOM is listed as 4, but should be 9.

Similar change needed for the screws.

I can make the changes and submit a PR if you like.

Add a belt tensioner for Y axis

Could be nice to have support on the Y motor, just like on the original design there's a part that goes behind the motor to make it lay flat to the rods

This will make sure motor will be 100% perpendicular and mount will not bend with higher temperature of the motor

Issue :
psu_lower_mount is off by 1mm (in height)

Why :
The PSU holes on official aluminum frame DXF file are not present. My measurement was 1mm off...

When will be fixed :
I will fix during the first build because I would like to see how it goes with cables. I would like to keep the PSU as close as the original one to ensure good compatibility with MK2 / MK2s /MK2.5 (and next updates if they will exists)

Hello! Is there a way to open those files? I can not open any file

Hi all,

I am working on v2.0 (check dev branch) and I need the dimensions of the MK3 PSU and PSU cover (assembled or not). The MK3 PSU cover looks a bit different than MK2s but dimensions seems to be very close.

Thanks for your help :)

This spool holder works great with the bear upgrade. https://www.thingiverse.com/thing:1832235

Cables clip sources file is missing. In the mean time, you can get them from here : https://www.thingiverse.com/thing:2676595

hello,

For step 14 on the mk3 full bear instructions, it says to put the end caps on, but the issue is the openbuilds angle connectors are on the outside extrusion instead of the inside per the instructions on the previous pages. Oddly enough the pictures on step 14 page show the corner connectors on the inside extrusion for some reason.

Either way there is a discrepancy here.

Add a DXF file with addition holes for the extrusions

The y-motor mount of the MK3 is different to the MK2s in one important way:
the MK2s mount uses 3 screws to fix the motor, the MK3 mount only uses 2. Is this intentional?

MK2s:

MK3:

Since both mounts are for NEMA 17, the holes should be same.

BTW: The after market EINSY board can be bought with an endstop! so even though Prusa Research does not ship the MK3 with one, it would not be a problem to reuse the MK2s mount design with endstop.

The openbuildstore links for the 20x40 are giving a 404 error inside the store page

My Z axis smooth rods are exactly 8mm. The openings for them in the z top pieces were around 7.6-7.7mm. I ended up having to use a mallet to get them flush with the top of the frame.

I ended up breaking them and reprinted several additional copies just in case. All had the same narrow holes, even when I dropped the perimeters from 3 to 2. All of my other pieces fit fine.

Alternatively, it may be easier to skip step 12.3 and just install the smooth rods in the z tops first. Once the rods are flush with the z top, it's easy to press them into place through the bearings and into the motor mounts.

To add the t-nut to hold the rambo cover on the side, you need to remove the top part t-nut to slide other down.

For the MK3, the "assembly helper" is 106mm, not 96mm. In the assembly instructions, Step 7 correctly refers to the distance as 106mm in item 3, but in item 4 incorrectly refers to this distance as 96mm. It appears this is a copy and paste error from the MK2/S or MK2.5 assembly instructions.

hi thank you for your reply...

you add print setting is for all parts or only psu and holder mount ? thanks

drill new holes print 3d for frame Z ?

https://d17kynu4zpq5hy.cloudfront.net/igi/prusa3d/cVb12VhTHbQq66UY.huge

I have quite many 2020 T-Slot extrusions left over from a previous build. From the documentation it is not clear to me if V-Slot is really required, or if I can use regular T-Slot extrusions?

I know that the build uses 4020 extrusions, but if V-Slot is not really required, I'd give it a shot with 2020 T-Slot extrusions and share my experience.

Is it just me or does step 6 in the full upgrade manual not show the required 4 tee nuts for the hinge and power supply mounts?

it seems like the download buttons for the STL files on the Full upgrade is missing?
they are present on the half upgrade btw

Minor thing as I assume you used the same settings as the other end caps, but still.

Also, if I could make a suggestion, having a separate table for quantity of printed parts on one page, and then a table for print settings on another page doesn't make much sense to me. Maybe just put a column for quantity in the print settings table and link from the BOM to it?

To be tested

This is a very interesting mod made by Mike Mayer. Cables will need protection such as heat shrink tube or printed part.

https://www.facebook.com/groups/prusabearupgrade/permalink/986032741557036/

Thank Mike for this very nice idea!

I just finished step 7 of the half upgrade assembly instruction. Even when carefully measured the y-carriage did not run perfectly smooth. I then aligned the rods perfectly with the following procedure. Perhaps this might be included into the tutorial.

1. After installing the y-carriage with the heat bed, unscrew the rod holders with only one bearing so it can be smoothly moved along the aluminium extrusion (lower rod in figure 7.4 https://github.com/gregsaun/prusa_i3_bear_upgrade/blob/master/half_upgrade/manual/assembly_instructions/img/fig7.4.png)

2. Pull the carriage to the front. Push at the front rod holder from the top (so it cannot move) and slide the carriage to the back. (this should push the back rod holder if it is not perfectly positioned)

3. Push on the back rod holder from the top and slide carriage to the front.

4. Repeat step 2 and 3 two to 5 times. After that, the carriage should be able to move freely back and forth without moving/wobbling the rod holders.

5. Fix the rod holders again by gently pushing from the top and tightening both screws

At least for my case, this resulted in an excellent movement of the carriage along the whole y axis. I also tested this method with completely offset rod holders. It consistently lead to the same result.

Cheers

It has been a long time since my last Prusa build, and I forgot that the left z motor has a shorter cable than the right z motor. I ended up having them reversed until it was time to connect the cables, and I ended up having to disassemble a lot of parts to get the motors in the right place.

A simple "Caution: Be sure the z motor with the shorter cable is on the left side. The z motor with the longer cable should be on the right" would save others the same grief. This could be added to step 12.1 and or fig 12.1.

From Jeepguy42 on Thingiverse :
https://www.thingiverse.com/thing:2562174/#comment-1551150
http://www.openbuilds.com/threads/prusa-i3-bear-edition.10274/#post-58904

1. Step 08 the instructions begin with installing the Y-axis rod holders on the right side of the frame, but the illustration shows what I would consider to be the left side
2. Step 13 (MK3 and MK2.5) should have an additional T-nut added in the left Z-vslot for the rambo base lower mount in step 16.
3. Add a step to test all t-nuts threads that are inserted.

In this drawing

https://github.com/gregsaun/prusa_i3_bear_upgrade/blob/dev/full_upgrade/for_mk3/doc/vslots_length.png

It has the side uprights at 334 mm, but doesn't appear to take into account the fact the bottom side extrusions are laying flat in the V2 model. Shouldn't they then be 354mm ?

prusa3d/Original-Prusa-i3#76

Current bearing mount cannot move in their holder, however holder might move a bit if not tighten enough and not a good idea to have this on a part that is such out of center and do not have a precise position.

Hi Grégoire

Could you please show your Slic3rPE settings for printing with PETG (post screenshots or config files) ?
You have a document https://github.com/gregsaun/prusa_i3_bear_upgrade/blob/master/manual/print_settings.md with some of the settings, but there are a lot of other, retraction parameters, cooling, speeds, etc.

I'm new to printing with PETG, just tried to print a rod_holder.stl with default settings (temp 230C/75C) - the result is fine but there is stringing in holes and "non-print" travels..

I'm new to GitHub too. So If it is not the right place to place a post - please feel free to delete it.

With this build you need a lot of different none standard length v-slots. (You can buy them here in 5cm steps pre cut). It would be nice to have more of them the same length and in 5cm steps of length e.g. 350mm instead of 331mm.
For the screws its quite the same. Try to use the same legth everywhere and standard length like 10mm/16mm/20mm (8mm and 12mm are also fine but are normally not included in a set - here).
Additionally tee nuts are not a good choice.
It would be handy to have a step file combining all the parts as a overview.
I did quite the same as your full upgrade with my own design with standard v-slot length and only 20x20. Your design is better in a lot of ways but you need to cut the v-slots to quite some strange sizes.