LR 2.5 is the evolved LabRat 3D Printer . Printing volume 180 x 180 x 180 mm3.
In this new configuration the quality and speed of printing has increased over LR. I have printed at 0.05 layer height (Marvin), at 150mm/s (box lid) and Benchy at 100mm/s.
I did use all component from LR (except 2x150 profiles) and extended the printer to I3 configuration. There are three iteration :
A. Y carriage from LR (single 2020 V slot profile);
B. Y axis 2040 or 2x2020 V-slot, Y carriage 3 wheels .
C. Y axis 2040 V-slot profile and Y carriage with bed support, 4 wheels. Remix of Tevo Tarantula Bed Support_V2.
Also Y motor mount is modified and added a new X carriage with wheel spacers and belt holders integrated and wheel tensioner with eccentric.
I used the same 180x180 bed from LR printer. Extruder Pitan and hotend V5 clone.
For assembling, the profiles being stacked, doesn't need to be cut precisely, but it is necessary to measure very precise every join position to obtain the desired perpendicularity between axis.
Only for Z axis I used metallic corner brackets, the rest of them are printed. As T-nuts I used M5 nuts filed to fit in profile channel.
In actual configuration could accommodate up to 200 x 200 bed (with a single 2020 profile for right z axis). 214 x 214 bed doesn't fit but the configuration can be easily expanded.
All stl files are in zip archive.
Added a 3mf file for 3d view of assembly
Some other photos and videos

11.05.2020 added Y carriage for 214x214 (220x220) bed (untested)