The main characteristics of foundry management in developed countries are: many process control items, standard and detailed process management, and strict and quantitative control scope; Implement the process without compromise; Pay attention to development and creativity, and continue to develop high-tech castings with higher intangible value.
1. There are many process management control items, the process management is standardized and detailed, and the scope is strictly quantified
The goal of casting production is to produce qualified and consistent castings with the highest efficiency and lowest cost. Qualified quality means that the casting size is qualified, without surface and internal defects, and the material properties meet the requirements. Consistent quality means that the performance and quality of each batch of castings and different batches of castings are the same and consistent.
1.1 Process management control
In order to achieve this goal, we need a complete set of processes and equipment. All equipment serves the process, and the process required for any process of production must be controlled. Foundries in developed countries have established strict control scope for all projects that have been proved to be controlled in terms of science and technology and where they can be controlled. The raw materials are subject to strict inspection and control, including the composition and specification of various metal materials and non-metallic materials. The parameters in the process are also strictly controlled, such as the compaction rate, wet strength, dry strength, moisture, crushing index, permeability, effective clay content, volatile matter, burning loss, dead clay content, temperature, sand hardness, etc. Many domestic foundries do not detect the effective clay content. The content of dead clay in molding sand is high, so the moisture content is high. For example, for the chemical composition of nodular cast iron, the general control range (mass fraction, the same below) of foundries in developed countries is ± 0.05% C, ± 0.1% Si.
The author has inspected the foundries of other non-ferrous metals and superalloys in Europe, and their control process and parameter requirements are also strict. It is not allowed to change the detection and control parameters without the consent of the competent department. In addition, the execution of each process has original document records, which cannot be changed at will.
1.2 Selection and matching of instruments and equipment
In order to achieve the control goal, there must be corresponding equipment and instruments. Electric furnace smelting or duplex smelting shall be adopted, and carbon content shall be detected by carbon analyzer, and the remaining ten components shall be detected by spectrometer. If there is no electric furnace smelting and spectrometer rapid analysis, foreign customers will not buy your products. The spheroidization rate test uses diamond polishing paste to prepare samples, and the sample quality is close to the photographic level; Check the depth of the white mouth with a sample plate; The mechanical properties can be accurately measured by the equipment configured by computer; The casting sample shall be inspected by a three-coordinate inspection bench; The cleaned castings shall be inspected with special measuring tools and special clamps. Each process has original document records. Spheroidization rate and internal defects shall be inspected by ultrasonic, and surface cracks shall be inspected by X-ray. The coupling agent used for inspection is the coupling agent specially used for inspection of castings.
In short, all equipment required to ensure the process must be purchased.
In order to realize the production with high efficiency and low energy consumption, the production shift shall be arranged so that the production can be carried out continuously and the consumption of materials and energy can be reduced. For example, enterprises with cupola and electric furnace are arranged to work 12 hours a shift and 4 days a week. The process should also consider the convenience, safety and efficiency of workers. For example, the wax pattern for producing superalloy precision castings is light green, which protects vision and is conducive to production; Select the most suitable height for the workbench of the cleaning department.
1.3 Quality management
Due to the complexity of the production process, no matter how advanced the quality certification, good management and strict implementation are, it is also inevitable to produce waste products. The problem is the attitude towards waste products. A good quality system means that everyone is a quality controller. Never let a waste product pass through his own network, never let a waste product leave the factory, let alone the phenomenon of shoddy goods. International quality certification (IS09000) and all kinds of special certification are very strict, and fraud is not allowed. The inspection of quality certification does not depend on whether there are problems, but on whether there is credibility. Problems can be solved through efforts and improvement to meet the requirements of certification. If you cheat, you will lose your credibility and will not be certified. In developed countries, it is rare for foundries to give any special treatment to certification units and personnel, and there are few cases of fraud. Even so, some customers also stipulate that a third party must be present to witness the mechanical property inspection and jointly fill in the mechanical property inspection report, which shows the strict requirements.
All places that can be controlled by instruments and tools are controlled by instruments and tools. All instruments and meters are regularly inspected, calibrated and recorded.
In order to achieve high productivity, the allocation and management of equipment should be systematic and complete. The author visited many enterprises in Europe and the United States, and found that the equipment of the enterprise is not advanced, but has good matching and high reliability. This will reduce the time lost due to the shutdown of the whole line due to the failure of one equipment, and also enable the entire equipment system to meet the requirements of producing high-quality castings. There are many manufacturers in China, many of which are very advanced and world-class, but some of them are poor, unreliable and have poor equipment matching. For example, many famous foundries in China do not have a three-coordinate inspection bench and other advanced inspection equipment, resulting in that even if good castings are produced, there is not enough inspection equipment and data to support their product quality. European and American enterprises also have strong maintenance teams.
Some peers in the technology and management departments of domestic casting enterprises worry about whether such strict process procedures and their strict implementation will cause production stoppage, affect production rhythm and productivity due to a problem in a certain link. In developed countries, there is no production halt due to strict process procedures and their strict implementation, which affects productivity.
In fact, loose process procedures and not strict process procedures can not improve productivity, but are harmful to the improvement of productivity and product quality. On the contrary, it is precisely because of such strict and meticulous process procedures and their strict implementation that the energy consumption of castings in developed countries is far less than that in China, while the labor productivity and total output value are far higher than that of Chinese foundries.
A German foundry, through strict process management system, produces as-cast low temperature high impact ductile iron without heat treatment. The attached test bar and casting body can meet all the mechanical properties requirements of low temperature and high toughness ductile iron. It is no exaggeration to say that the optimized process procedures and their strict implementation are actually the fundamental reason, or know-how, for the whole industrial system of developed countries to continuously produce high-quality products.
1.4 Personnel training and post setting
The training of personnel should focus on practical results and what needs to be trained. The main methods include training classes (industry training classes, university training classes), and mentoring between old and new employees. The training is very targeted and practical. Training is not a diploma, not a certificate, but only for the needs of work.
If you can use machinery to complete the process, you will never use people; One post needs one person, and never two. For example, one worker in a foundry is responsible for the sand treatment system of two green sand production lines, responsible for all feeding, pulverized coal, new sand, water, etc., checking and controlling the performance of molding sand, recording data, and also responsible for sample sorting; A specially-assigned person in the cleaning workshop is responsible for inspection, including scribing inspection of samples, casting size inspection, ultrasonic inspection of spheroidization rate, internal defects, X-ray inspection of surface cracks, management of inspection tool library, etc.
2. Strictly implement the process
Process is regarded as the production law of enterprises. Once the process is formulated, everyone from workers to management and technical personnel is responsible for implementing the process. Although the workers' education level is not high, the quality of implementing the process is not low, and the implementation of the process regulations is absolutely uncompromising. If the process conditions are not met, the workers will never operate. For example, if the temperature and composition of molten metal are unqualified, the furnace workers will never come out of the furnace; If the temperature of molten metal in the ladle exceeds the specified pouring temperature range, the pouring worker will never pour; Would rather be cast into ingots; If the molding sand temperature exceeds the specified temperature, the molding worker will not conduct molding; Products with unqualified hardness, size and surface quality will not be released.
The equipment and raw materials are all for the process. In order to implement the process without compromise, no cost will be spared. For example, the spheroidization rate of ductile iron is tested by polishing with diamond polishing paste, and the sample quality is close to the photographic level; Three-coordinate inspection platform is used for dimensional inspection of casting samples. Other advanced inspection equipment for internal defects, such as X-ray and ultrasonic flaw detection, are necessary for samples.
3. Pay attention to development and creativity, and develop high-tech castings with higher intangible value
In recent years, foundries in developed countries have made efforts to improve customer service, actively participated in the development, design and production of high-tech castings and high-margin castings with higher added value. In recent years, due to the continuous improvement of the properties of cast metal materials, the improvement of casting methods and the emergence of new casting methods, it has provided a new development space for new castings and casting design. Some metal castings even replace plastic shells.
The famous Intemational Waukesha foundry in Portland, Oregon, the United States, which produces automobile castings, redesigned the assembly consisting of four steel castings from its competitors to produce one ADI casting. From 1991 to 2003, it has produced more than 40000 tons of ADI castings. In 2003, the truck rear spring seat was redesigned as ADI casting, and its weight was reduced from 34 pounds to 27 pounds.
Smith Foundry in Minneapolis in the United States changed the originally designed track drive wheel assembled from 84 steel parts into an integral ADI drive wheel casting, reducing weight by 15% and cost by 55%. Users can save $190000 per year. Compared with the original assembly, it saves 30 minutes of assembly time, improves wear resistance and looks more beautiful. It can be seen that the design potential of castings is huge, and the design, innovation and improvement of castings are endless.
According to the author, many foundries in Europe and America are cooperating with users to design, innovate and improve castings. Some companies have more than ten such projects every year. As the above examples show, at present, the main work of developing new castings by using new processes and new alloy materials is realized by combining the foundry and users. However, companies with casting design as their business have emerged in developed countries. These emerging companies adopt computer solidification simulation technology, computer casting design technology, and combine with casting users and casting manufacturers to develop new castings at the fastest speed. It can be said that the future castings will have more functions, better performance and cheaper price. China's foundry industry should understand the development of the international foundry industry, grasp the opportunity, and further develop and improve the level of China's foundry industry.
