OTC DAIHEN FD-B4L Extended-Arm External Cable Robot Mechanical Structure & Core Parts Analysis
In the OTC DAIHEN automated welding product line, the FD-B4L is a special industrial robot featuring a 2.0-meter ultra-long reach and external cable routing architecture. Unlike through-arm models, external routing allows the welding torch a greater range of postural movement, making it highly suitable for deep cavity or long seam welding of large boxes and construction machinery structural components. Due to the extremely long lever arm, its lower base (J1-J3 axes) utilizes high-rigidity, large-capacity cycloidal gearboxes to withstand massive leverage gravity overturning moments; the wrist (J4-J6 axes) integrates compact harmonic gearboxes and crossed roller bearings.
An extended reach means the physical torque borne by the gearboxes is extremely severe. When performing routine robot overhauls (such as replacing cycloidal gearbox grease, tensioning belts, or extracting/replacing internal highly flexible cables), please strictly follow the official factory exploded view and the parts list for each axis below. Do not mix different models of motors and grease:
📷 Figure 1: OTC DAIHEN FD-B4L Extended-Arm Industrial Robot Complete Mechanical Exploded View
2. FD-B4L Core Parts Reference Table by Axis
For the convenience of the workshop equipment department, we have consolidated the power units, reduction units, and cable accessories of the J1 to J6 axes into a comprehensive global matrix table. Please carefully cross-reference the circled numbers (1-20) in Figure 1:
| Axis / Location | Image Ref. | Official Part Number | Standard Part Name | Function & Maintenance Notes |
|---|---|---|---|---|
| J1 Axis (Rotating Base) |
① | W-L02641 | AC Servomotor | Provides main power for wide-range horizontal base rotation. |
| ② | W-L02116 | Cycloidal Gearbox | High-rigidity, large-capacity base main reducer. | |
| ③ | 100-0624 | Lubricating Grease | Liquid anti-friction grease dedicated for cycloidal gearboxes. | |
| J2 Axis (Lower Arm Pitch) |
④ | W-L02152 | AC Servomotor | Provides main power for extended lower arm forward/backward pitch. |
| ⑤ | W-L02117 | Cycloidal Gearbox | Core reducer bearing the extreme gravity overturning moment of the 2.0m extended arm. | |
| ③ | 100-0624 | Lubricating Grease | Liquid anti-friction grease dedicated for cycloidal gearboxes. | |
| J3 Axis (Upper Arm Pitch) |
① | W-L02641 | AC Servomotor | Provides main power for upper arm up/down pitch. |
| ⑥ | L10725F00 | Cycloidal Gearbox | Heavy-duty reducer driving the extension of the upper arm. | |
| ③ | 100-0624 | Lubricating Grease | Liquid anti-friction grease dedicated for cycloidal gearboxes. | |
| J4 Axis (Arm Rotation) |
⑦ | W-L02148 | AC Servomotor | Provides main power for upper arm axial rotation. |
| ⑧ | W-L02034 | Harmonic Gearbox | Compact flexspline harmonic reducer. | |
| ⑨ | W-L02551 | Crossed Roller Bearing | Precision rotary bearing carrying lateral turnover and torque. | |
| ⑩ | 2670-052 | Lubricating Grease | Flexible high-viscosity lubricating grease dedicated for harmonic gearboxes. | |
| ⑪ | 2670-017 | Lubricating Grease | Supplemental grease for crossed roller bearing and gear cavity. | |
| ⑫ | 100-1491 | Lubricating Grease | Dedicated anti-friction grease for local mating contact surfaces. | |
| J5 Axis (Wrist Pitch) |
⑦ | W-L02148 | AC Servomotor | Controls the up/down pitch angle of the welding torch. |
| ⑬ | L10725H00 | Harmonic Gearbox | High-precision harmonic reducer for the wrist. | |
| ⑭ | W-L01945 | Timing Belt (J5) | Toothed transmission synchronous belt connecting motor and gearbox. | |
| ⑮ | 100-1516 | Sealant | Original factory high-temperature anaerobic sealant for leakage prevention. | |
| ⑩ | 2670-052 | Lubricating Grease | Dedicated flexspline lubricating grease for harmonic gearboxes. | |
| J6 Axis (Flange Rotation) |
⑯ | W-L02147 | AC Servomotor | Controls the rotation of the welding torch end flange. |
| ⑰ | W-L02036 | Harmonic Gearbox | Zero-backlash harmonic drive for end flange. | |
| ⑱ | W-L02551 | Crossed Roller Bearing | Heavy-load crossed roller bearing for end flange. | |
| ⑮ | 100-1516 | Sealant | Anti-oil leakage sealant for end cover. | |
| ⑲ | 2670-053 | Lubricating Grease | Dedicated anti-friction grease for end high-frequency friction pair. | |
| ⑪ | 2670-017 | Lubricating Grease | Supplemental grease for gear cavities or bearings. | |
| ⑫ | 100-1491 | Lubricating Grease | Dedicated anti-friction grease for local contact surfaces. | |
| Cables & Accessories (Global) |
— | L10525C00 | Cable Assembly (1) | Highly flexible main axis cable from the rear of the rack to the upper arm. |
| — | L10525D00 | Cable Assembly (2) | J5 and J6 axis motor communication flying leads inside the upper arm. | |
| — | L10525E00 | Cable Assembly (3) | J5 and J6 axis auxiliary cables inside the upper arm. | |
| — | L10470H00 | Cable Assembly (4) | Dedicated J6 axis cable inside the upper arm. | |
| — | L10470C00 | J5 Axis Unit Assembly | J5 axis mechanical housing assembly for the wrist. | |
| — | L11140B00 | J6 Axis Unit Assembly | J6 axis mechanical housing assembly for the wrist. | |
| — | L10485Q00 | Power Cable Assembly 1 | High-voltage servo power supply line inside J1 axis. | |
| — | L10485S00 | Power Cable Assembly 2 | Servo power supply line from J2 axis to the upper arm. | |
| ⑳ | W-L01399 | Battery (Absolute) | Backup lithium battery pack maintaining the mechanical zero coordinates of the encoders. |
* Note: Items with an “Image Ref.” of “—” in the table represent wiring harness components hidden inside the main body, which cannot be visually indicated in the external skeleton exploded view. Please perform disassembly and replacement according to the original factory manual.
💡 FD-B4L Extended-Arm Robot Overhaul & Maintenance Red Card Warnings:
- Extended-Arm Model Gearbox Grease Replacement (Forced Pressure Release to Prevent Oil Burst): Because the B4L model has a lever arm of up to 2.0 meters, the cycloidal gearboxes of its base and lower arm endure physical stresses far exceeding standard models, easily accumulating high temperature and high pressure inside the cavity. When injecting new grease (e.g., 100-0624) into the J1-J3 axes, you must absolutely open both the inlet and outlet ports simultaneously, and let each axis of the robot run continuously at 30% low speed for 20-30 minutes after injection to thoroughly “release pressure”. If the oil plug is forcibly sealed without fully exhausting the high-pressure air inside the cavity, the rapidly expanding air during operation will instantly burst the servo motor’s internal skeleton oil seal, causing massive grease backflow and completely burning out the AC servo motor.
- External Cable Interference & J5/J6 Axis Belt Abnormal Fatigue: The FD-B4L is a typical external cable routing robot. If an unreasonable allowance is left when bundling the wire feed hose and water cooling tube at the front end, it will cause the external cable package to interfere and pull on the wrist during large-angle robot rotations. This massive external force will react directly on the timing belts of the J5/J6 axes (
W-L01945/W-L01496), causing the belts to be severely stretched or even experience tooth jumping. When replacing belts, a professional sonic tension meter must be used to accurately adjust them to the Hz frequency baseline specified in the official maintenance manual. - Absolute Battery (W-L01399) Live Hot-Swap Rule: The No. ⑳ backup battery located inside the base maintains the spatial absolute position memory of the robot’s 6 axes. Never unplug the old battery connector while the main power to the control cabinet is disconnected! Once unplugged during a power outage, all encoder origin coordinate parameters will instantly clear to zero. When replacing the
W-L01399battery, the control system must remain powered on, and the new battery must be plugged in immediately after removing the old one.
🛠️ Get Real-Time Quotes for FD-B4L Robot Motors, Gearboxes & Cables
The health of a large extended-arm industrial robot’s “skeleton and muscles” directly determines the trajectory repeatability in space. Simply provide the required official part numbers (e.g., W-L02641 Motor, W-L02116 Cycloidal Gearbox, W-L01399 Battery), and our automated spare parts system will quickly match and output an accurate, ready-to-ship quote for you. Whether you need original Cycloidal/Harmonic grease for routine maintenance or internal highly flexible cable assemblies for a complete overhaul, feel free to contact us directly: