Foreword :
Eleven years have passed since China joined the WTO (December 11, 2001). The opening of the market, information networking, global competition, and rising labor costs have brought unprecedented opportunities and enormous challenges to China's manufacturing industry. How can it survive, develop, and thrive in such a fiercely competitive environment? Rapid response to market changes, comprehensive information technology infrastructure, improved production efficiency and yield rates, reduced inventory backlog, a sound supply chain system, and a complete quality management system are crucial. Currently, most of my country's automobile manufacturers (hereinafter referred to as OEMs) already have a complete information system, including ERP (Enterprise Resource Planning) systems, MES (Manufacturing Execution System) systems, SCM (Supply Chain Management) systems, and underlying production control systems. OEMs require auto parts companies to integrate with their production, logistics, and quality systems. How can companies meet the requirements of OEMs, improve their management level, and enhance their core competitiveness? The implementation of an MES system for auto parts is imperative!
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The following is a detailed introduction to the component MES system :
1. Functional architecture of the component MES system :
Figure 1 Functional Architecture of Component MES System
The component manufacturing execution system (MES) serves as a bridge connecting the upper-level ERP system and the lower-level execution system. It covers production management, material management, quality management, equipment management, and system management, comprehensively building a production system platform to achieve transparent production and intelligent manufacturing goals. The system's functions are described below:
2. Production Management :
2.1 Order Management
Orders are crucial to the entire MES system, spanning the entire process from planning to execution. For component suppliers, orders fall into two main categories: Just-In-Time (JIT) orders and Inventory-Ordered (IOE) orders. Vehicle manufacturers send production plans and order sequences to component suppliers in advance, and the suppliers produce and ship according to the order. Inventory-oriented orders specify the required delivery time and quantity. Component suppliers arrange production, warehousing, and delivery based on their production cycle time, equipment status, bottleneck processes, and other factors. Both types of orders can be imported into the system via ERP interfaces or file transfers, and order management can be implemented.
2.2 Order Scheduling
Adopting different order scheduling methods for different order types is an important function of the MES system. The key to MES system order scheduling lies in how to schedule orders and respond to unexpected production events to ensure production continuity and feasibility.
JIT order scheduling: JIT orders are for orders that already have production sequence instructions. Component companies mainly combine the orders with BOM information to refine them into their own component planning orders and assembly orders.
Scheduling for Inventory-Based Orders: For inventory-based orders, there are only corresponding time points and quantities. Component companies need to comprehensively consider their own processing and production capabilities, processes, bottleneck processes, equipment conditions, and other factors to schedule production. They can use a reverse scheduling production method to schedule finished product orders and semi-finished product orders.
JIT order scheduling diagram :
Figure 2 JIT Order Scheduling
Diagram of scheduling for inventory orders :
Figure 3. Inventory-Order-Order Scheduling
2.3 Order Broadcast
The order scheduling results are sent to the corresponding production lines for processing, and a material requirements plan is generated and broadcast.
The order scheduling results include :
- Production date
- Train schedule
- Production sequence
- Production order details
2.4 Production Tracking
Production tracking is crucial for the execution of the entire MES system. Through production tracking, we can understand the execution status, completion status, and corresponding completion quality information of the production plan.
Production tracking employs different methods depending on the specific process requirements, primarily including :
- Paper barcode
- RFID
- Process flow card
- Kanban method
2.5 Process Management
Process management involves collecting data on production processes, making process judgments based on process standards, and improving processes through trend analysis of process reports to increase production efficiency and reduce defect rates. Process management is crucial for component manufacturers, and effective process optimization is the driving force for their sustainable development.
Process management example: Through process management tracking and process data collection, the entire production process can be tracked and analyzed.
Figure 4 Process Flow Management
3. Materials Management :
3.1 Batch Management
For auto parts manufacturers, production is mainly based on batch production, and batch management is carried out throughout the entire process from raw materials to semi-finished products to finished products.
Batch management enables the tracking of raw materials, semi-finished products, finished products, processing, and testing. Key batch information includes:
- Incoming material batches
- Casting batch
- Machining batch
- Test batch
- Semi-finished product batches
- Finished product batch
- ...
Batch management can be carried out through methods such as barcodes, laser engraving, and CNC engraving to manage batch information.
3.2 Formula Management
Recipe management is a unique feature in automotive parts MES systems.
The formula is directly related to the success or failure and quality of the product. By combining formula management with rigorous on-site process management and operational requirements, product quality can be guaranteed.
Formula management is mainly used in industries such as automotive parts casting and tires.
3.3 Material Pulling
The production method of the MES system for automotive parts differs from the push production of the ERP system. The push production method involves preparing materials in advance according to a plan, placing them in their corresponding storage areas, and then delivering them to the production line in advance for production use. The MES system promotes a pull production method, aiming to drive production through material pull, ensuring timely material replenishment, maintaining production continuity, and effectively reducing material stockpiles at the production line.
There are several main material pulling methods, which can be optimized and combined according to the requirements of different component manufacturers.
Figure 5 Material Pulling Method
3.4 Electronic Picking
Electronic picking primarily targets assembly-type automotive parts manufacturers. It combines the product BOM (Bill of Materials) to select the required parts and quantities for assembly, and binds them to containers to achieve a product-to-part binding.
Electronic picking is linked to material pulling. It can reduce the requirements for warehouse staff to identify products and improve overall efficiency.
Electronic picking process :
Scan order number → Pick materials according to BOM prompts → Picking complete → Container delivery
Electronic sorting lines, aiming to save space and improve space utilization, often adopt a U-shaped line structure. See the diagram below:
Figure 6. Distribution of Electronic Picking Shelves
Figure 7. Electronic picking image
3.5 Shipment Management
Shipments are made in accordance with order requirements, and JIT orders are shipped according to the JIT order sequence.
4. Quality Management :
4.1 Incoming material quality inspection
Incoming materials are inspected according to batch number. Depending on the quality requirements, methods such as sampling and 100% inspection are adopted. The inspection results, along with the batch number and supplier information, are used as the basis for quality traceability and supplier evaluation.
4.2 Initial inspection, random inspection, and patrol inspection during production.
For component manufacturers that produce in batches, initial inspection, random inspection, and routine inspection are essential for ensuring product quality.
First inspection: Produce 1-3 products first, conduct a comprehensive inspection of the products, and record the quality information and quality judgment results as the basis for mass production.
Sampling inspection: Conduct random inspections of products before they are put into storage according to the sampling principle, and record the quality information of the random inspection.
Inspection: On-site quality personnel conduct regular inspections of products processed online and record inspection quality information.
4.3 Quality Data Collection
Quality data is collected and stored during the production, processing, and testing processes through data acquisition methods to form product quality archives, which serve as the data basis for quality SPC analysis and allow for the traceability of quality information through quality traceability functions.
4.4 Prevent omissions and errors.
Quality control measures to prevent omissions and errors are primarily aimed at assembly-type component manufacturers. By inspecting the components assembled in the previous process through the next process, it is possible to determine if any components were missing or if the assembled components match the product. Through layer-by-layer quality control, the goal of "not creating defects, not passing on defects, and not accepting defects" can be achieved.
4.5 Quality SPC
By collecting quality data and analyzing product quality factors according to quality analysis and standards, quality reports are generated. Graphical displays are used to determine quality trends, supporting product quality improvement. (See figure:)
Figure 8. Example of SPC analysis
4.6 Quality Traceability
Quality traceability is a national requirement for product quality and also a requirement for vehicle manufacturers for component quality. It requires forward and reverse traceability of product usage information, production and processing information, actual process data, material batch barcodes, quality test data, personnel information, etc., through product barcodes or raw material batch barcodes.
5. Equipment Management :
5.1 Equipment Ledger Management
Equipment ledger management mainly focuses on managing basic equipment information, including equipment name, equipment model, purchase time, maintenance cycle, usage cycle, depreciation cycle, equipment manufacturer, warranty period, etc. Equipment ledgers are used to effectively count and manage equipment, forming equipment files.
5.2 Equipment maintenance and repair management
Based on equipment maintenance cycles, such as daily, weekly, or monthly inspections, perform regular maintenance on the equipment, including recording the maintenance details.
Record equipment malfunctions and abnormal repair information during the production process, analyze the causes of equipment malfunctions and abnormalities, and promptly replace and maintain equipment parts.
5.3 Equipment Data Acquisition
Device data is collected via Ethernet, bus networks, databases, files, etc., and displayed in conjunction with the device monitoring interface.
The main methods of data collection are :
- OPC method;
- PLC data acquisition method: Data is acquired from the device via bus or intermediate relay.
- Intermediate table in the database;
- File transfer;
- SOCKET communication, message queue;
- ...
5.4 Equipment Monitoring (PMC)
The Equipment Monitoring and Control (PMC) system is used to monitor production status in real time, measuring and tracking the operating conditions of production equipment. When production problems occur, the PMC system will alert workshop personnel. The system monitors production cycle time, equipment uptime, downtime due to malfunctions, and equipment failures. The PMC system communicates with field devices (PLCs, thiamine equipment, crude benzene equipment, and other control systems) via TCP/IP or OPC Ethernet protocols. The PMC system also records production and alarm information in the PMC database for future report generation.
The monitoring screen is shown in the picture :
Figure 9 Equipment Monitoring
5.5 Equipment OEE Analysis
OEE is an advanced analytical method widely used by many world-class companies to evaluate the overall utilization rate of equipment.
OEE is composed of three elements: availability, performance ratio, and quality rate. The operation of a single piece of equipment or even the entire plant is affected by the cumulative effect of these three elements. OEE is the product of the percentages of these three elements, and the result can be used for production analysis and benchmark design.
That is: OEE = Availability × Performance Ratio × Quality Rate
Availability – the percentage of products that are in normal use within the production plan (used to assess reliability) or the percentage of available time out of calendar time (days/weeks/years) (used to measure equipment utilization), i.e., the probability that equipment can work.
Performance ratio—the percentage of actual production speed to maximum rated production speed per unit time. Performance ratio can measure speed loss (e.g., inefficient metering, mechanical failure).
Quality rate – the percentage of marketable products produced per unit of time out of the total products.
Through OEE analysis, users can gain a clear understanding of equipment efficiency and identify production bottlenecks.
Figure 10 Equipment OEE Analysis
5. 6ANDON System
The ANDON system is a system that uses audible and visual alarms to prompt relevant personnel to respond promptly.
The main hardware components are :
- PLC;
- Call button box, pull the cord;
- ANDON alarm light;
- Music player;
- LED large screen/LED TV;
- ...
Based on the functions of the ANDON system, it can be divided into the following categories.
- The ANDON device is used to prompt on-site maintenance personnel to respond promptly to equipment malfunctions and for repairs.
- ANDON material is used to replenish materials at the line in a timely manner.
- ANDON Quality is used for quality control to prevent the spread of quality problems.
6. Supplier Platform :
Automotive parts companies use the MES system supplier platform to publish information such as procurement information, production plans, inventory information, invoicing information, return information, raw material price inquiries, supplier evaluation, and message notifications to suppliers via Internet Explorer, and receive feedback from suppliers, thus establishing a two-way communication channel.
Figure 11 Supplier Platform
