¶ BMCU Assembling
⚠️WARNING
Do not hot-plug or unplug the connection cable between the BMCU and the printer while the printer is powered on. -> Risk of damage to the BMCU motherboard
You may receive a different version of the BMCU motherboard, or download a different version of the stl model, please check before printing and assembling
¶ Version & author
- v1.1&v1.31
- 130 Improved shell version
- Editor: 山竹
¶ Step 1: Testing the PCB Hardware
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Ensure Successful Firmware Burning for the BMCU Main Board (Firmware V0.2)
- Use a USB-to-TTL burner to power the main board. The red indicator light should turn on.
- Connect the printer using an MX3.0 4-pin cable. The main board's blue indicator light should turn on.
-
Verify the Functionality of the Secondary Board
- Power the secondary board via USB. When connected to the main board:
- RGB Lights:
- The RGB light on the secondary board should show blue (port 1 is blue, ports 2, 3, 4 are off).
- The light flashing is considered normal.
- Photoelectric Indicators:
- The two photoelectric indicator lights should remain off under normal conditions.
- When the photoelectric sensors detect obstruction, the corresponding rear indicator light should turn on.
- For material detection:
- RGB Light Behavior:
- When feeding, the RGB light should turn blue.
- When a material jam occurs, the RGB light should turn red.
- RGB Light Behavior:
- When powered by a
Bambulabprinter:- The RGB lights on both the main and secondary boards should remain blue.
- The two photoelectric indicator lights should remain off unless obstruction is detected, in which case the corresponding rear indicator lights should turn on.
- The RGB lights should consistently remain blue.
- RGB Lights:
- Power the secondary board via USB. When connected to the main board:
-
Ensure Proper Communication Between the Main Board, Secondary Board, and Printer
- When the main board is connected to the printer, the printer's consumable menu should display the AMS option.
- When the photoelectric sensors are obstructed, the consumable status should update to reflect the material detected.
¶ Step 2: Mechanical Assembly part 1 - Feeder/extruder, needs to be repeated 4 times
-
Print the Complete Feeder Housing Set
- Print the feeder housing according to the provided model.
- This tutorial is based on the following model:
https://makerworld.com.cn/models/741793 (Modified by 青铜板子cn).
-
Attach the Pneumatic Fitting (PC4-M6)
- Screw the PC4-M6 pneumatic fitting into the buffer assembly.
- Caution: Ensure it is screwed in straight to avoid misalignment.
-
Assemble the Spring and the 62B Axle Sleeve
- Take one large spring (0.5 × 6 × 10mm) and a 62B axle sleeve.
- Assemble them as shown in the diagram below:
-
Compress the Spring and Snap it into the Base Housing
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Ensure the Components Move Freely
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Assemble the Gear Structure
- Take two small gears (Gear 182A) and one short axle (2 × 10mm).
- Assemble them as shown in the diagram.
- Ensure the protruding sections on both sides of the axle are of equal length for proper alignment.
-
Assemble the Large Gear and Long Axle
- Take a large gear (Gear 242A) and a long axle (2 × 20mm).
- Assemble them to match the diagram, ensuring one end of the axle is pressed to the width indicated by the arrow in the diagram.
-
Select Two Triangular Parts (Replaceable)
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Assemble the Large Gear with the Triangular Parts
- Attach the large gear to the triangular parts as shown in the diagram.
- Important: Pay close attention to the orientation of the gear to ensure correct assembly.
-
Assemble the Remaining Small Gears and Secure the Components
- Attach the remaining two small gears to the structure.
- Place the cover over the assembly and tighten it using M2 × 8 self-tapping screws.
- Ensure all screws are securely fastened to maintain stability.
-
Insert Axle Sleeves
- Insert 5 white 62B axle sleeves into the positions shown in the diagram.
- Ensure they are securely pressed into the base and top covers.
- Prepare BMG Extrusion Components
- Gather the following parts:
- Extrusion wheel with screw hole
- Black set screw
- One thick axle (5 × 22mm)
- Two bearings (MR85ZZ).
- Assemble the Extrusion Wheel
- Assemble as shown in the diagram, paying close attention to orientation.
- One end of the thick axle must be flush with the bearing (to allow a flat surface for the magnet).
- Don’t forget to install the black set screw.
- Place the Extrusion Structure
- Insert the extrusion structure into the base housing.
- Insert the Gear Group
- Place the gear group into the axle sleeves, ensuring the screw side faces downward, as shown in the diagram.
- Install Two Long Axles
- Prepare two long axles (2 × 20mm).
- Insert them into the 62B axle sleeves.
- Install two 20082B double-layer straight gears, starting from left to right.
Note in image :
The left-down arrow gear is placed first,
The right-up arrow gear is installed later
- Assemble the Motor and Worm Gear
- Combine the FF-130 motor with the 682A worm gear.
- Ensure the assembly is flush; misalignment can cause gear jamming.
- Insert Axle Sleeves into Cover Plate
- Snap the 62B axle sleeves (white parts) into the holes on the cover plate, as shown in the diagram.
- Attach Motor Cover Plate
- Fix the motor cover plate with two M2 × 4 flat-head screws.
- Solder Motor Wires
- Solder the connection wires to the motor.
- Red dot indicates the positive terminal.
- Red dot indicates the positive terminal.
- Install and Test the Motor
- Place the motor into the base housing and align it with the fixing slot.
- Power the motor with 3V-12V to test if all gears rotate smoothly.
Note in image :
Motor with sticker side down.
The positive terminal should face downward for easier soldering later.
- Apply Lubricant and Secure the Cover
- Apply lubricating grease to the gears if desired.
- Place the cover plate on top and secure it with M2 × 8 screws.
- Insert the Replaceable Optical Sensing Module
- Place the optical sensing module into its designated slot.
- Thread Motor Wires Through Top Cover
- Thread the motor wires through the slots on the top cover and secure the cover in place.
- Insert Radial Magnet
- Insert a radial magnet (6 × 2.5mm) into the red-circled hole on the top cover.
- Important: Ensure smooth rotation and use the correct magnet size (not replaceable by a standard magnet).
Note: This magnet is used to detect the angle of rotation of the extrusion gear to obtain the material feed length.
- Secure the Back Cover Screws
- Tighten the five screws (M2 × 8 self-tapping screws) on the back cover, as shown in the diagram.
- Install the Secondary Board
- Insert the secondary board and solder the motor wires (observe polarity).
- Secure the secondary board with two M2 × 8 self-tapping screws.
- Prepare Remaining Components
- Gather the following parts:
- Two needle roller bearings
- BMG-supplied axle
- Non-perforated extrusion gear
- Printed wrench.
- Assemble as shown in the diagram, ensuring the correct orientation.
- Place the Small Spring
- Place a small spring (0.6 × 4 × 10mm) in the position shown in the diagram.
- Snap the wrench into place, ensuring the spring is properly seated and compressed.
- Insert Short and Long Axles
- Use a short axle (D2 × 10mm) and a long axle (D2 × 20mm).
- Insert the short axle first, followed by the long axle, through the wrench holes into the axle sleeve.
- Verify smooth movement when pressed and rotated.
- Secure the Final Cover
- Adjust the motor wires, place the final cover, and secure it with four M2 × 8 self-tapping screws.
- The extrusion assembly is now complete.
- Insert Transparent Material
- Insert transparent material into the indicated holes, ensuring it reaches the bottom, then cut it off.
- This will guide the indicator light.
¶ Step 3: Mechanical Assembly part 2 - Base Installation and Connections
-
Connect the Feeders
- Insert the PH2.0 10-pin male-to-male reverse cable (80mm in length) into the feeder interface.
- Insert the PH2.0 10-pin male-to-male reverse cable (80mm in length) into the feeder interface.
-
Install Feeders onto the Top Cover
- Attach the feeder units to the top cover of the base, aligning them with the designated holes.
- Place the cables into the wire grooves to keep them organized.
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Secure Feeders
- From the underside of the top cover, tighten the screws (M2 × 8 self-tapping screws) at the red-circled positions.
- Repeat this process to secure all feeder units.
-
Mount the Mainboard
- Install the mainboard onto the base, aligning it with the red-circled screw holes.
- Secure it with M2 × 8 self-tapping screws.
-
Assemble the Base
- Combine the base parts as shown in the diagram.
- At the circled positions on the bottom of the base, secure it using M3 × 14 self-tapping screws.
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Connect Ribbon Cables and Finalize Assembly
- Insert the ribbon cables into their respective connectors.
- Place the wire cover over the cables and secure it at the circled positions with M3 × 14 self-tapping screws.
¶ Done! 
The BMCU complete system assembly is now finished.