With four autonomous rail transporters carrying finished coils, great achievements have been made in succession: the rail designed for loaded vehicles guarantees both velocity and stability, while that designed for empty vehicles further quickens the transportation speed; Shougang Cold Rolling's finished product warehouse runs efficiently; and the autonomous rail transporters shuttle back and forth busily and prosperously without any interference.

The digitalization of inventory dynamics management at Shougang Cold Rolling’s "Lighthouse Factory" has achieved positive results. In 2022, the total inventory decreased by 3,200 tons compared with the previous year, releasing the cash flow. The 100% fulfillment rate of contracts for accurate material preparation increased by 20 percentage points, marking a great improvement in customer satisfaction. Compared with the previous year, the cycle time of cold-rolling materials decreased by 1.8 days, while the management level and efficiency were greatly enhanced.

Program development

Breakthrough from "zero" to "one"

After a laser beam scans the front of the steel coil, the automatic robot arm completes the last labeling process with a "crack", and the finished steel coil is transferred to the finished product warehouse by crown block for delivery. "Since the test running of the inventory dynamics management model, the total inventory has decreased by 4.7% compared with the same period last year, which has also filled in gaps in business management such as inventory target segmentation and material turnover days," Tian Jing, product manager of the inventory dynamics analysis model and application cases, said proudly.

The inventory dynamics analysis model is a key application case in Phase I of the Shougang Cold-rolling Company's Digital Transformation Project, which was independently developed by the Stock Manufacturing Department, Cold-rolling Manufacturing Department and Beijing Shougang Automatic Information Technology Co., Ltd. In the past, inventory management lacked scientific means, the accuracy of target setting was not high, and material turnover depended solely on people's supervision. With the multidimensional display and analysis of each piece of inventory and all cold-rolled coil materials enabled by the model, users can access visual inventory-related information in order to identify problems, causes and improvement directions, which absolutely solves pain points such as inventory backlog, increased inventory age, superabundant material preparation and long disposal cycle.

On this basis, from project scope determination, objective definition and resource coordination to planning, task assignment, real-time tracking and regular review, Tian Jing and his team members repeatedly polished the "1+6+N" model framework; that is, "one calculation interface plus six display interfaces plus several backstage base tables". The application cases have become a "cockpit" model through which users can quickly obtain the related data of inventory materials and all-round application experience. Upon opening the model, you can access the display and analysis of inventory in various dimensions such as space, time, business type and responsible department. "With wider perspectives, finer granularity and more dimensions, I have a 'new understanding' of my job as an 'elder worker' with 18 years of experience. Therefore, this is a truly rare opportunity to develop ourselves," Tian Jing said modestly.

Business disposal

Upgrade from "static" to "dynamic"

With the sound of keyboards clacking, the staff of the finished product warehouse formulate the delivery plan on their computers. When the plan is uploaded to the intelligent warehousing system, the logistics plan enters circulation.

After the packaging machine automatically scans the steel coil's information, the offline steel coil is uploaded to the production execution system. The scheduling model optimizes the scheduling instructions according to the production line speed, stock and inventory location, and displays the scheduling instructions on the display screen of the crown block operator. The operator then puts the steel coil in storage, and the recorder on duty in the entry room summarizes all the data.

Before the implementation of the digital model of inventory dynamics management, relevant information was transmitted in the form of "static" tables. This system was inconvenient for quantifying the inventory target before and after the process, and could not reflect the influence of related factors such as material preparation cycle, manufacturing cycle, in-plant transportation and customer feedback in an objective, accurate and timely manner, which led to an unhealthy inventory structure and low logistics and turnover efficiency. "The digitalization of inventory management not only enables employees to predict problems, but also helps them identify directions for improvement and take measures quickly. In the "man-machine interaction" aspect, it has realized the "dynamic" upgrade of management logic from "people looking for data in the past" to "data waiting for people now," Jia Yanhe, Deputy Director of the joint-stock company’s Auto Sheet Manufacturing Department, said excitedly.

In the test running stage of the application cases, problems exposed in the production process need to be dealt with at any time. Application cases can only be examples when they are used accurately and well in the field. 

"When the system becomes 'dynamic', the business disposal should also remain 'dynamic'. Now the workload is two or three times more than usual, which is the most important period, so laptop computers should be carried at all times," said Ren Junru, a busy but joyous scientific research management engineer of the Manufacturing Department. "What we are doing now will undoubtedly benefit latecomers, because people's experience will now become a computer program. Man-made interference has been reduced and the efficiency of production lines has been improved. With instructions transferred to the scene directly and successively, it’s worthwhile no matter how tired we are. "

Post integration

Evolution from "several" to "zero"

An unmanned crown block moves up and down, and its wire rope and load hook operate accurately. This scene is clearly displayed on the LCD screen and console display in the centralized control room of the crown block, which realizes the regular sharing of physical logistics and information flow. "Tasks that could only be completed with several people's cooperation can now be completed by just one worker, two handles and three screens, which effectively alleviates the contradiction between the production line capacity and logistics transportation capacity," said Zheng Xiaoyong, a logistics management engineer of the finished product annealing operation area, confidently introducing the test results of a remote crown block with centralized control in the finished product warehouse.

With the function of intelligent charging and automatic operation on the track, the four steel coil transporters have replaced the original forklifts and other vehicles for carrying steel coils into the warehouse. Effectively reducing the operating pressure of existing crown blocks and the transshipment volume of forklifts and vehicles in the intermediate warehouses, these four transporters not only improve the transportation efficiency of steel coils, but also decrease the safety risks and increase the degree of environmental friendliness and energy conservation. “The crane drivers were once known as 'trapeze artists', but now they step into the 'cockpit' of the centralized control room. With the support of digital means, we can adjust posts such as crane driver, crane conductor and forklift driver easily, and post integration from 'several' to 'zero' is just around the corner," Zheng Xiaoyong said firmly.

In order to upgrade the system, besides the software, hardware and management mechanisms, the supporting resources also include the upgrading of people. Currently, the system boasts more powerful functions, and closely related posts have been integrated, which also puts forward higher requirements for the technology and skills levels of employees.

"In the past, the work required help from several posts, so the process and response time were very long. Now it's controlled by just one person who decides everything. The system is also equipped with alarm and emergency braking functions, which not only ensure safety, but also make the connection between the front and rear processes more compact," said Jiang Xuechuan, aa centralized control crown block operator. "The company has arranged unified skills training, and we can only resume work after passing the examination. This also requires us to 'make up for missed lessons' quickly in terms of business knowledge and operation skills. Only by reaching the standard of 'one specialty and multiple abilities' can we adapt to the new positions and new models after integration."

Shougang Cold rolling focuses on the digitalization of inventory dynamics management and control, and promotes "business, technology and organization" at the same time. With the inventory dynamics management model moving from "zero" to "one", process control from "static" to "dynamic" and some positions from "several" to "zero", Shougang Cold Rolling has formed a unique "new method" for refined inventory management which provides useful references for all bases to make good use of digital means and continuously consolidate their basic management work.