1. Introduction
In rolling mill operations, continuous and stable material handling is essential to ensure production efficiency and product quality.
The roller table is a fundamental piece of equipment used throughout the rolling process, connecting individual machines into a continuous production line.
Roller tables are widely applied in billet handling, rolling operations, cooling, cutting, finishing sections like, collecting and bundling, of a rolling mill.
2. Functions of Roller Tables
A roller table is used to transport rolling piece longitudinally along the production line.
Its main functions include:
- Charging and discharging billets from reheating furnaces
- Feeding rolling piece into rolling stands and receiving rolled products
- Transferring products to cooling beds and downstream finishing equipment
In a typical rolling workshop, roller tables account for a significant portion of the total equipment weight.
Therefore, their design, operation, and maintenance have a direct impact on:
- Production efficiency
- Product quality
- Operational stability of the rolling line
3. Classification of Roller Tables
3.1 Classification by Function
3.1.1 Charging and Discharge Roller Tables
Installed upstream of the rough rolling mills to receive billets transported by crane, or installed downstream of the billet heating furnace to receive heated billets sliding out of the furnace. These tables are subject to heavy loads and frequently withstand impact forces.
3.1.2 Working Roller Tables
Working roller tables are installed before and after rolling stands and operate under high load and high frequency.
They include:
- Main working roller tables: continuously active during rolling cycles
- Auxiliary (extension) roller tables: used when rolling long products that exceed the length of main roller table
- Mill rollers (stand rollers): installed within the mill stand to guide rolling pieces as close as possible to the rolls
3.1.3 Transport Roller Tables
Transport roller tables are used exclusively for conveying materials with relatively light loads.
They are divided into:
- Input roller tables: transport rolling pieces to rolling mills
- Output roller tables: transfer rolled products to subsequent processes
3.1.4 Special Roller Tables
Special roller tables are designed for specific process requirements, including:
- Collecting (inclined) roller tables
- Lifting roller tables
- Moving roller tables
- Flipping roller tables
- Double-layer roller tables
- Furnace roller tables (with cooling structures)
3.2 Classification by Drive Type
3.2.1 Centralized Drive Roller Tables
- Multiple rollers driven by a single motor
- Power transmitted via gear reducers and gear systems
- Lower investment cost
Typical application:
Input and working roller tables in heavy rolling mills
3.2.2 Individual Drive Roller Tables
- Each roller driven by an independent motor
- Simple structure and convenient maintenance
- Failure of one unit does not affect the entire system
Typical application:
Long product conveying systems
3.2.3 Non-powered (Gravity) Roller Tables
- No drive system
- Material moves by gravity along an inclined plane
Characteristics:
Energy-saving but limited controllability
4. Application in Bar Rolling Mill Projects (Engineering Example)
The following configuration illustrates the practical application of roller tables in a bar rolling mill project.
4.1 Delivery Roller Table
Function:
To receive billets from the continuous casting machine and transport them to the roughing mill entry.
Example specifications:
- Length: approx. 13 m
- Roller spacing: approx. 1000 mm
- Number of rollers: 12
- Speed: 0.1–1.5 m/s (variable frequency control)
Design consideration:
Adaptation to high-temperature conditions and stable conveying
4.2 Cooling Bed Output Roller Table
Function:
To transport cooled products from the cooling bed to downstream processes.
Example specifications:
- Multiple groups (e.g., 5 groups)
- Total length up to approx. 58 m
- AC centralized drive system
- Reversible operation near the shear area
Design focus:
Coordination with cutting operations
4.3 Shear Area Roller Tables
Includes roller tables before and after the shear.
Functions:
- Transport rolling stock
- Coordinate with cutting operations
Example specification:
- Speed: approx. 2 m/s
- Reversible operation
- Fast braking capability
- Drive type: Centralized driving roller table, reversible operation and quick application of the brake.
Design focus:
Ensuring cutting accuracy and synchronization
4.4 Swing Roller Table
Function:
To swing downward during cutting in coordination with the shear blade, ensuring cutting quality.
Example specification:
- Synchronized with shear operation
- Dynamic positional adjustment
- AC centralized driving roller table, quick brake
4.5 Finished Product Handling and Bundling Roller Tables
Includes:
- Roller tables before and after shifting stands
- Bundling roller tables
Functions:
- Transport cut-to-length products
- Support product collection and bundling
Drive types:
- Centralized or individual drive depending on location and function
