Design of Automated Rockwool Production Line Stacking System

Due to the serious dust generated by rockwool products, long-term inhalation causes significant harm to the body, and the labor intensity of manual stacking is high, resulting in harsh working conditions. Therefore, it is urgent to automate the rock wool stacking process. Currently, the development of control systems has already made considerable achievements, with simple PLC control systems or DCS control systems based on PLC, as well as control systems based on PLC and FCS being maturely used in real production, and widely applied. Based on this, this article mainly analyzes and discusses the design of the automated stacking system for the rockwool production line.

Rockwool Production Line: Stacking Process Flow

Taking two side-by-side rock wool boards as an example, the stacking process is as follows: Upper fork extends → Rock wool board enters the upper fork → Upper fork retracts → Rock wool board stacks to the lower fork → Lower fork descends a certain distance → Rock wool board stacks to a designated thickness → Lower fork descends to the lowest position → Rock wool board enters the conveyor belt → Rock wool board leaves the lower fork area → Lower fork rises → Rock wool board initially separates and turns → Rock wool board further separates → First rock wool board enters the lifting area → Conveyor belt 3 stops, lifting rises → First stack of rock wool enters the packaging machine → Lifting descends, conveyor belt 3 starts → Second rock wool board enters the lifting area → Lifting rises → Second stack of rock wool enters the packaging machine.

Structure Scheme of the Automated Stacking System

The main production process of rock wool boards is as follows: Natural rocks are melted into fibers at high temperatures, becoming inorganic fibrous material (rock wool), then an appropriate amount of binder is added to solidify and press it into shape, and then cut into rock wool boards of specified sizes. The cut rock wool boards are usually single-layered, side-by-side 2-3 pieces continuously conveyed on the conveyor belt. After passing through the stacking unit, they become single-row multiple layers and are fed into the heat shrink packaging system for packaging, and finally loaded onto trucks for shipment. Therefore, the main function of the stacking unit is to quickly stack 2-3 side-by-side rock wool boards into multiple layers and convert them into a single row for conveying. The automated stacking system, in addition to meeting the aforementioned functional requirements, also needs adjustable stacking speed to match the speed of the entire rockwool production line. Additionally, it should be able to adjust for different specifications and sizes of rock wool boards and the number of stacking layers.

The mechanical structure of the system is mainly divided into stacking and conveying parts. The stacking part is composed of a frame and upper and lower forks. The frame is a supporting structure, with the upper part equipped with horizontal guides and cylinders for the horizontal reciprocating motion of the upper fork, and the lower part equipped with vertical guides, a servo motor, and rack-and-pinion mechanisms for driving the vertical up-and-down movement of the lower fork. The upper fork is used to receive the rock wool boards conveyed from the previous process and stack them onto the lower fork. Every time a layer is stacked, the lower fork automatically descends a certain height. After reaching the predetermined layers and thickness, the lower fork places the rock wool boards onto the conveyor belt. The conveying part consists of 3 sections of conveyor belts and a lifting device. The speeds of the 3 conveyor belts increase sequentially to separate the stacked rock wool boards by a certain distance and use the second curved conveyor belt to change the direction of the rock wool boards. Conveyor belt 3 sequentially sends the separated and redirected rock wool boards into the lifting area, where the lifting device then sends them into the heat shrink packaging machine.

Composition of the Control System

The automated rock wool stacking system is a subsystem of the rockwool production line control system. It can operate independently or respond to commands from the main system.

To meet the automation stacking needs of the rockwool production line, the designed automated stacking system based on PLC and the touch screen can communicate with the main control system of the rockwool production line through fieldbus. After on-site commissioning and improvement, issues such as uneven dropping, impacts during stacking and delivering, and inconsistency between the overall stacking time and production pace have been resolved. The entire system is stable and meets production requirements. This system will promote the full automation of rock wool production, effectively improve production efficiency, and improve working conditions.