README.md

Bear X axis and Extruder

BearMera for E3D Hemera extruder

Table of contents

1. Introduction
2. Compatibility
3. Bill Of materials
4. Printed parts
5. Print settings
6. Assembly guide
7. Optional parts
8. Source
9. Thank you
10. Credit and inspiration

Introduction

This page contains all the files and information to use the Bear X axis with the original E3D Hemera.

The Hemera needs a dedicated mount to be used with the Bear X axis. All hardware and printed parts needed are available in the Bill of Materials section below.

Note: The BearMera reduces a little the print surface to 205x240mm (compared to 210x250mm for Original Prusa).

Compatibility

The BearMera has a smaller print surface compared to the Original Prusa, Bear and Bondtech extruders: 205x240mm for BearMera, 210x250mm for Bear extruder.

The BearMera is compatible with Original Prusa as well as Bear frame. You must use the Bear X axis in both cases.

This BearMera is only compatible with the Bear X axis.

This BearMera is NOT compatible with the original Prusa X axis.

You will need to replace all printed parts if you are already using the Bear X axis (with another extruder) of version equal or smaller than 0.7.0-beta.

Bill Of materials

Hardware BOM for Original Prusa printers

This is the list of extra material you will need from original Prusa extruder and X axis.

Part	Quantity (pce)	Detail	Example Link
E3D Hemera Direct Kit	1	24V for MK3(S)(S+) 12V for MK2(S) and MK2.5(S)(S+)	E3D-Online store
Hotend fan	1	Stock Hemera fan or higher specifications (yet unknown)
M3x8mm socket head screw (ISO 4762)	3	Check your Hemera package	McMaster-Carr
M3x10mm socket head screw (ISO 4762)	12		McMaster-Carr
M3x18mm socket head screw (ISO 4762)	16		McMaster-Carr
M3x25mm socket head screw (ISO 4762)	2		McMaster-Carr
M3x40mm socket head screw (ISO 4762)	3		McMaster-Carr
M2x12mm socket head screw (ISO 4762)	2	⚠️ MK2(S) or MK2.5(S) only	McMaster-Carr
M3 Hex nylock nuts (DIN 985)	3
M3 Hex nuts (DIN 934)	15
M3 Square nuts (DIN 562)	6	1.8mm thick and 5.5mm wide
M3 Steel washer (DIN 125), 0.5mm thick	1
Zip ties 2.5x100mm	5
Dowel pin diameter: 3mm, length: 15mm to 15.8mm	1	Must fit the 2GT idler bearing. 📌 Cut a M3 screw if you can't find one

Additional BOM for scratch build

Part	Quantity (pce)	Detail	Example Link
Nema 17 stepper for X axis LDO 42STH38-1004A100CM	1	Datasheet	Prusa
Nema 17 stepper for Z axis integrated Lead screw Tr8x8 (P2x4) and nut LDO-42STH34-1004L321E100CM	2	Datasheet	Prusa
Nozzle Fan	1	Minimal specifications: - CFM: 3.8 - Static Pressure: 11.3 mmH2O - Bearing type: ball bearing	Prusa
Inductive Sensor	1	Diameter of 8mm, length around 35mm
Filament sensor with magnets, steel ball and cables	1	1x IR Sensor: GitHub Prusa 1x Steel ball 7mm diameter 1x Magnet 20x6x2 1x Magnet 10x6x2	Prusa
2GT 16T pulley	1	3mm bore	E3D-Online store
2GT 20T idler	1	3mm bore smooth or toothed Check this optional part for E3D idler
Smooth rods	2	8mm diameter H6 370mm long	Prusa
LM8UU bearings	3	Prusa
Gates LL-2GT RF belt	1	6mm width 880mm long	E3D-Online store
Nylon cable 2.85-3.00mm diameter 500mm long	1	You can use 2.85mm sample or cleaning filaments

Printed parts

Download links for the BearMera and X axis:

• BearMera and X axis for MK2(S) and MK2.5(S): bearmera_mk2_mk2s_mk2.5_mk2.5s.zip
• BearMera and X axis for MK3(S) and MK3(S): bearmera_mk3_mk3s.zip

Print settings

⚠️ Warning: The parts have been designed and tested with the parameters below and it is important to follow them to avoid issues like part cracking, bad bridging, not enough stiffness or wrong tolerances. Be sure to have a well calibrated machine and extruder. Check our guide here for calibrating extrusion multiplier

• Slicer : PrusaSlicer recommended
• Infill type : Gyroid recommended
• Support : No
• Brim : No
• Detect thin walls : No
• Perimeters width (internal and external) : 0.45mm

Part	Quantity	Layer Height	Infill	Perimeters	Top/Bottom Layers	Filament Type
body_back	1	0.20mm	20%	4	5	PETG
body_front1	1	0.20mm	20%	4	5	PETG
cable_cover	1	0.20mm	20%	4	5	PETG
nozzle_fan_duct	1	0.20mm	20%	3	5	Read note2 below
nozzle_fan_spacer	1	0.20mm	20%	4	5	PETG
pinda_mount	1	0.20mm	20%	4	5	PETG
ptfe_collet_clip	1	0.20mm	20%	3	5	PETG
y_axis_end_stop	1	0.20mm	20%	3	5	PETG
x_carriage	1	0.20mm	20%	4	5	PETG
x_carriage_back	1	0.20mm	20%	3	5	PETG
x_end_idler	1	0.20mm	20%	4	5	PETG
x_end_idler_tensioner	1	0.20mm	20%	4	5	PETG
x_end_motor	1	0.20mm	20%	4	5	PETG
cable_guide_back_a	1	0.20mm	20%	4	5	PETG
cable_guide_back_b	1	0.20mm	20%	4	5	PETG

Note¹: If you intend to use the E3D Volcano hotend with BearMera, this STL should be replaced with the modified volcano body_front listed below among official Optional parts

Note²: The nozzle_fan_duct needs to be printed with a heat resistant filament like ABS, Extrudr GreenTec Pro, annealed HTPLA, PC and probably much more. Don't forget to compensate for shrinkage accordingly to the filament type you are using.

You can find more details about recommended filaments in on our FAQ.

Assembly guide

The assembly guide is available on guides.bear-lab.com.

Optional parts

Here is a list official optional parts for your BearMera.

Name	Description	Link
E3D Volcano	A body_front to support E3D Volcano	optional_parts/e3d_volcano
Fan washer	Allow a stronger tightening of the E3D fan by avoiding it to twist	optional_parts/fan_washer

Source

All source files in Fusion 360 and STEP format can be download here.

Thank you

Thank you to E3D-Online for their warm encouragement and for having sponsor this development with a free Hemera.

Credit and inspiration

• E3D Hemera Prusa i3 MK2(S) upgrade: https://e3d-online.dozuki.com/Guide/Hemera+Prusa+i3+MK2-2s+upgrade/138?lang=en