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1. Selection of the main parameters of the equipment (l) Productivity: The productivity of a piece of equipment is generally expressed as the amount of products it can produce per unit of time (minutes, hours, shifts, years). For example, a boiler is measured in tons of steam evaporated per hour ； The air compressor is measured by the volume of compressed air it outputs per hour ； Refrigeration equipment is rated by its cooling capacity per hour ； The engine in terms of power ； The pipeline is based on the production rhythm (the time interval between two consecutive products) ； Pumps are specified by head and flow rate. However, for some equipment for which it is not possible to directly estimate output, it can be measured using key parameters such as the center height of the lathe, the spindle speed, and the maximum pressure of the press. Equipment productivity must be in line with the company’s business policies, factory planning, production schedules, transportation capabilities, technical expertise, labor force, power supply, and raw material availability. It is not advisable to pursue higher productivity at all costs, as this can lead to production imbalances and inadequate service delivery; instead of achieving optimal results, it will result in losses. Equipment with high productivity generally features a high degree of automation, requires significant investment, consumes a lot of energy, and is complex to maintain. If it fails to meet the planned production volume, the average cost per unit of product will increase. (2) Processability: The most fundamental requirement for machinery and equipment is that it must meet the technical requirements of the product’s manufacturing process. The ability of a device to satisfy these process requirements is referred to as processability. For example: Metal cutting machines should be able to meet the requirements regarding the dimensional accuracy, geometric shape accuracy, and surface quality of the parts being processed ； Milling machines are difficult to use as a substitute for coordinate boring machines in situations where they are required ； Heating equipment must meet the highest and lowest temperature requirements of the product’s manufacturing process, as well as requirements regarding temperature uniformity and temperature control accuracy. In addition to the above basic requirements, the requirements for device operation and control are also important; generally, it is required that devices be easy to operate and allow for flexible control. Equipment with high production volumes should have a high degree of automation, while equipment used for hazardous and toxic tasks requires automatic control or remote monitoring and control. 2. Reliability and maintainability of equipment (l) Equipment reliability Reliability is a prerequisite for maintaining and improving equipment productivity. When people invest in purchasing equipment, they expect it to operate without failures in order to achieve the desired outcomes; this is the concept of equipment reliability. Reliability depends to a large extent on the design and manufacturing of the equipment. Therefore, the design and manufacturing quality of the equipment must be taken into consideration when selecting it. When selecting equipment reliability, it is desirable to have as long an average time between failures for its main components. This can be analyzed from various aspects such as the safety factor chosen in the equipment design, redundancy design, environmental considerations, stability of components, safety features, and the interaction between humans and machines. As products are continuously updated, the requirements for the reliability of equipment also increase. Equipment designers and manufacturers should provide reliability metrics for product design to help users make choices when selecting equipment. (2) Repairability of equipment: Similarly, people expect that the equipment purchased with investment can be easily repaired in case of a malfunction; in other words, the equipment should have good repairability. When selecting a device, its maintainability can be evaluated from the following aspects. ①The technical drawings and documents for the equipment are complete. It enables maintenance personnel to understand the equipment’s structure, making it easy to disassemble, assemble, and inspect. ②The structural design is reasonable. The overall layout of the equipment’s structure should comply with the principle of accessibility, ensuring that all components and parts are easily accessible for inspection and maintenance. ③The simplicity of the structure. As long as the usage requirements are met, the design of the equipment should be kept as simple as possible; the fewer components that need repair, the better. It should also be easy to disassemble, allowing for quick replacement of wear-prone parts. ④Principles of standardization and modularization. The equipment should use standard parts and components as much as possible, be able to be divided into several separate parts, units, and assemblies, and be able to be assembled into a complete unit without the need for special methods. ⑤Advanced structure. The equipment should be designed with automatic parameter adjustment, automatic wear compensation, and automated preventive measures as guiding principles. ⑥Capacity for condition monitoring and fault diagnosis. The instruments, meters, sensors, and associated equipment available on the device can be used to measure parameters such as temperature, pressure, voltage, current, vibration frequency, power consumption, efficiency, as well as the dynamic characteristics of the output parameters of the finished products and the device itself. This enables determination of the technical condition of the device and identification of the locations where faults may exist. In the future, more and more efficient, precise, and complex devices will come equipped with diagnostic capabilities. Fault diagnosis will become one of the key aspects of device design, and detection and diagnosis software will also become an essential part of such devices. ⑦Provide special tools and instruments, an appropriate amount of spare parts, or convenient supply channels. Furthermore, good after-sales service quality is necessary, and the repair techniques should be as suitable as possible for the conditions in the area where the equipment is located. 3. Safety and operability of the equipment (1) Safety of the equipment: Safety refers to the equipment’s ability to ensure production safety; in other words, the equipment should have the necessary safety protections and mechanisms in place to prevent accidents involving people or machinery, as well as economic losses. When selecting equipment, if new safety components are introduced, it is necessary to require them to provide documents such as test and operation reports. (2) Operability of the equipment The operability of equipment falls under the scope of ergonomics; the general requirements are convenience, reliability, and safety, in line with ergonomic principles. The main considerations usually include the following: ① The operating mechanism and its installation location must meet the requirements of labor protection regulations and be suitable for operators of average build. ②The physiological limits of the operator must be fully taken into account; they should not be forced to endure operational forces, activity rhythms, movement speeds, endurance levels, etc. that exceed their physical capabilities within the prescribed operating time. For example, the position and operating force of the control handles and wheels must be appropriate, while the control points and rhythm of the foot pedals, along with their operating force, must comply with labor regulations. ③The design of the equipment and its control room must meet the requirements for reducing mental fatigue among workers. For example, the noise in the equipment and its control room must be below specified values ； Device control signals, paint colors, hazard warnings, and so on must all meet the physiological and psychological requirements of the vast majority of operators as much as possible. 4. Environmental protection and energy efficiency of equipment: The environmental friendliness of equipment used in industries such as manufacturing, transportation, and construction refers to the extent to which factors such as noise, vibration, and emissions of harmful substances affect the surrounding environment. When selecting equipment, it is necessary to ensure that its noise levels, vibration frequencies, and emissions of harmful substances are within the limits specified by ** and regional standards. The energy consumption of a device refers to its consumption of primary or secondary energy. It is usually expressed as the energy consumption per unit of operating time of the equipment ； In the chemical, metallurgical, and transportation industries, equipment energy consumption is also evaluated based on the energy consumption per unit of output. When making a selection, regardless of the type of enterprise, the equipment purchased must meet all the standard requirements stipulated in the **Energy Conservation Law**. 5. Economic efficiency of equipment: The scope of definition for the economic efficiency aspect in equipment selection is quite broad; each company can, based on its own characteristics and needs, select the key factors that affect equipment economic efficiency for analysis and evaluation. The main economic factors to consider when selecting equipment include: ① Initial investment ； ②Adaptability to products ； ③Production efficiency ； ④Durability ； ⑤Energy and raw material consumption ； ⑥Maintenance and repair costs, etc. The initial investment in equipment mainly includes purchase costs, transportation and insurance fees, installation costs, costs for auxiliary facilities, training expenses, customs duties, etc. When purchasing equipment, one should not simply seek the lowest price at the expense of considering other relevant factors; special attention must be paid to costs such as downtime losses, maintenance, spare parts, and energy consumption, as well as various administrative expenses. In summary, equipment economics is measured based on its life-cycle costs, with the goal of achieving the highest economic efficiency in equipment investment on the premise that these life-cycle costs are reasonable.