Flender HB Gearbox Replacement in 75 Days: Cement Kiln Case Study
This case study documents a Flender HB gearbox replacement project for a cement kiln main drive in Southeast Asia. The replacement had to fit the existing installation interfaces and be completed within a 75-day project schedule.
Project Summary
| Existing gearbox | Flender HB series, parallel-shaft arrangement |
| Application | Rotary kiln main drive |
| Main constraint | Existing shaft layout, mounting pattern and installation dimensions |
| Project schedule | 75 days from confirmed order |
The Engineering Challenge
A replacement for an existing kiln-drive gearbox is not selected only by torque and ratio. The new unit also has to work with the installed foundation, shaft positions, couplings and surrounding equipment. In this project, the existing installation dimensions and interfaces became key design constraints.
Reverse Engineering and Interface Definition
Critical interfaces were reverse-engineered from the existing installation. The engineering stage included 3D modelling and technical drawing preparation so the dimensional arrangement could be reviewed before manufacturing.
For similar projects where original documentation is incomplete, see our Gearbox Reverse Engineering guide.
Gearbox Manufacturing Scope
- Custom helical gear set specified with carburized and ground alloy-steel gears
- Housing designed around the required mounting and shaft interfaces
- CNC machining of critical gearbox components
- Assembly, tooth-contact/marking checks and inspection
- Load testing according to the agreed project scope
The original project specification included 17CrNiMo6 for the carburized gear set and a ductile-iron housing. These material choices were project-specific rather than universal requirements for every replacement gearbox.
Delivery and Installation Compatibility
The completed gearbox was delivered within the 75-day schedule. The replacement was engineered to preserve the required installation geometry so the customer could use the existing machine interfaces without planned foundation or shaft-layout changes.
This is better described as a dimensionally compatible engineered replacement than as a generic “drop-in equivalent”: compatibility has to be verified against the actual machine and project data.
What Made the Schedule Possible?
- Early definition of the existing gearbox interfaces
- Rapid 2D/3D drawing review before manufacturing
- Coordinated gear, housing, shaft and bearing engineering
- Inspection checkpoints before shipment
- A project schedule built around the customer’s outage requirement
Independent Replacement Projects
KNGEAR develops replacement gearboxes for obsolete or unsupported industrial drives by engineering around the existing duty and interfaces. Each project is evaluated independently; suitability is based on the actual operating data, dimensions and application requirements.
See Gearbox Repair, Upgrade and Replacement Solutions for the broader lifecycle approach.
Need to Replace an Existing Industrial Gearbox?
Send the nameplate, drawings, operating data and installation dimensions for an engineering review.
Flender is a trademark of its respective owner. KNGEAR is an independent gearbox engineering and manufacturing company and is not affiliated with Flender.
A real 4.6 MW ball mill replacement gearbox project covering engineering review, case-hardened and ground gears, assembly inspection, running tests and final shipment.
Guide to reverse engineering obsolete industrial gearboxes, including inspection, dimensional recovery, gear geometry, materials, manufacturing and replacement evaluation.
Guide to evaluating an equivalent replacement gearbox using torque, ratio, shaft arrangement, mounting dimensions, loads, lubrication, cooling and retrofit constraints.