Remanufacturing
Remanufacturing of a worm gear reducer for heavy industry
Industrial site in Canada, constraints of an aluminum smelter: MERGER responds to the technical challenges of remanufacturing
Remanufacture a worm wheel and screw speed reducer identically
The ALCOA group (Aluminum Company of America), global aluminum player, requested MERGER for remanufacture a worm gear reducer. This reducer was used on screws of preheating in his Canadian subsidiary of Bécancour. In conjunction with its trusted distributor, APPLIED, already familiar with MERGER expertise, the project was launched in a demanding industrial context : corrosive environment, aging equipment (dating from 1997), and inability to modify the drivetrain existing.
A new replacement was therefore necessary, Alike, to ensure continuity of operation without altering the mechanical architecture in place.
Custom-made remanufacturing is inevitable
This key equipment displayed a wear internal gear advancement: pitting corrosion destructive, oxidation widespread, and progressive loss of performance. Given the impossibility of modifying the customer's drivetrain, the custom remanufacturing was necessary.
The wheel and worm system: precision and non-reversibility
A specific mechanical principle
The reducer to remanufacture was based on a specific mechanical principle: the gear wheel and worm screw. This system offers a sought-after advantage in steel industry and in aluminum smelters : non-reversibility. The screw, driven by a coupled motor, allows the wheel (made of bronze) to turn, but the reverse is not possible. This unidirectional operation secures movements and guarantees the stability of the preheating equipment.
This type of reducer is often chosen for its ability to deliver a high torque in a reduced footprint, with a significant reduction in speed.
Better motion control and quiet operation
In wheel and worm transmission, the rotation is therefore transmitted only in one direction: the screw drives the wheel, but the wheel cannot drive the screw. This non-reversibility is an undeniable advantage in aluminum smelters, particularly for equipment of lifting, adjustment or dosage (e.g. preheating screws or translation devices), because it prevents accidental rollback or any fall of load by gravity.
The sliding between the screw threads and the wheel teeth provides a damping effect that reduces vibrations and shocks. This feature contributes to the longevity of installations, noise reduction in the production halls, and at a more gradual wear, even in the presence of repeated operating cycles.
High torque transmission in a small and demanding footprint
Aluminum smelters use often imposing equipment in often constrained environments. The wheel/screw system makes it possible to drastically reduce speed while increasing torque output, with a more compact design than other types of reducers. This is particularly suitable for production lines where space is limited and where significant force is required to move or operate heavy components.
In aluminum smelters, ambient heat, alumina dust and humidity require high strength of materials. Reducers to wheel and worm screw can be made with a bronze wheel, particularly resistant to corrosion and wear, and surface treatments adapted to these extreme environments.
The technical and logistical constraints of this remanufacturing
Mechanical constraints: the imperative of precision and reliability
In a worm wheel system, the mesh quality is vital because the fluidity and lifespan of the transmission depend on it. This is why MERGER was particularly vigilant on these points during the operation:
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Perfect alignment of the axes to avoid excessive friction.
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Mastered games between the screw and the wheel to prevent functional play or blocking.
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Impeccable quality of the surfaces and finishes for slow and even wear.
Indeed, the consequences of a imperfect meshing, can be detrimental to the customer who is exposed to premature overheating by friction, a accelerated wear of the teeth, until the breakage, a loss of yield of the reducer or even costly production shutdowns for unplanned replacement.
In an aluminum smelter, where the lines are continuous and massive, the stopping of a single link (such as a preheat screw) can slow down or immobilize a furnace or complete unit, with significant economic losses.
Maintain smooth and transparent communication with project stakeholders
The reducer remanufactured by MERGER is intended for a aluminum smelter located in Quebec, while manufacturing is carried out in France. This situation requires a technical communication copy: the precise transmission of dimensions, plans or functional expectations is crucial. Distance requires a documentary rigor, with regular and transparent exchanges between stakeholders (distributor, customer and manufacturer).
Remanufacturing made easier by the history preserved at MERGER
With these strengths more than 75 years of experience, MERGER owns the the original data (plans, materials, tolerances, conditions of use) which facilitate the identical remanufacturing and ensure perfect integration into the existing chain.
Usage history allows you to know the charge cycles, past failures, replacements made, which helps identify critical components and anticipate recurring weak points.
The aluminum smelter, a unique industrial environment
The worm wheel speed reducer is used here as part of the preheating screw operation within an aluminum production site. This type of equipment is essential in the thermal transformation stages, before the MERGER or the extrusion of aluminum.
The environment imposes several mechanical and environmental constraints :
– High temperatures : The reducer operates near ovens or thermal devices. This induces significant thermal stresses on mechanical components (expansion, material fatigue, need for regular lubrication).
– Corrosive atmosphere : Aluminum is produced from bauxite by electrolysis, a process that generates corrosive vapors (fluorine, alumina dust), which can attack the materials of the reducer, in particular the bronze wheel.
– Continuous operating cycle : These devices often run 24 hours a day in a continuous production rhythm. This requires a robustness first-rate and controlled wear over time.
– Frozen footprint : The old reducers, like that oforigin of 1997, are integrated into existing kinematic chains, often not modifiable. Perfect mechanical and geometric compatibility is required during a remanufacturing.
Un unexpected stop of the speed reducer can cause a production line blockage upstream of the furnace or the casting line, but also major economic losses because an aluminum smelter operates on continuous cycles. Each unplanned shutdown generates costs in energy, wasted raw materials and missed delivery times. In addition, a shutdown can cause a risk of overheating or thermal imbalance in the facilities, which may damage other adjacent equipment.
Anticipating the need for maintenance or remanufacturing is therefore a major strategic issue for managers in the steel industry and in particular aluminum smelters.
Our service: identical remanufacturing
MERGER took charge of the entire remanufacturing of the reducer – a unit weighing approximately 200 kg – drawing on its expertise in mechanical gear transmissions. The intervention focused on the manufacture of the complete reducer to guarantee durability, performance and a perfect fit with the existing installation.
Each step was carried out in compliance with MERGER quality standards:
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On-site measurement with photo documentation,
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Integration of corrosion-resistant materials,
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Assembly controlled according to the rules of the art with the aim of reliability over time.
MERGER's intervention was not limited to the simple duplication of components. Each part was subject to rigorous controls such as:
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Careful preparation and deburring of the worm screw to prepare a perfect mesh between the rooms.
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Machining and processing of gears, to guarantee the corrosion resistance and longevity equivalent to, or even superior to, the original equipment.
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The final piece with various controls to ensure full compatibility with the rest of the drivetrain.
- On trials for validate the proper functioning of the device before sending it to Quebec.
MERGER, specialist in the remanufacturing and maintenance of industrial mechanical transmission systems, is at your disposal for your projects, whether it concerns wheels and worm screws, cylindrical, bevel or planetary gears.
