Equipment capacity refers to the number of product units produced per unit time. It is one of the main parameters of equipment, a key indicator for evaluating equipment production capacity and efficiency, an important basis for evaluating the benefits of equipment investment, and a key indicator that customers pay the most attention to when accepting equipment.
When communicating with clients and signing contracts, special attention should be paid to equipment capacity data. Client requirements should be carefully evaluated, and a basis for evaluation must be provided; otherwise, it will cause problems for subsequent delivery and acceptance. The unit for equipment capacity is generally: pieces per hour, also written as: PCS/H.
1) Theoretical productivity
Theoretical capacity refers to the capacity value calculated through equipment operation timing analysis. The capacity mentioned in a proposal usually refers to theoretical capacity. The formula for calculating theoretical capacity is: Theoretical Capacity = Unit Working Time / (C/T).
Unit working time is the unit of time used to calculate equipment capacity, usually in hours; C/T is an abbreviation for Cycle Time, which is the time required for the equipment to complete one full operation cycle, usually in seconds. For example, if the equipment's C/T is 6 seconds, then the theoretical capacity = 3600/6 = 600 units/hour. Cycle time is commonly used in production to describe and calculate the theoretical capacity of equipment.
Cycle time refers to the time required to produce one unit of product, or the time interval between production runs (simply put, how long it takes to produce one product), usually measured in seconds. Cycle time and C/T (Consumer/Time) are different expressions but have the same concept. The difference lies in the emphasis: cycle time focuses on the product, while C/T focuses on the equipment. In everyday speech, however, the distinction is minimal and they are often used interchangeably.
The concept of theoretical capacity discussed on the production floor differs slightly from that of theoretical capacity as explained by equipment manufacturers. On the production floor, theoretical capacity emphasizes the actual production capacity of the equipment under ideal conditions; we call this ideal capacity to distinguish it. If the timing estimates for each mechanism are too lenient during timing diagram analysis, the theoretical capacity will be less than the ideal capacity. Conversely, if the timing estimates are too tight, the actions are not fully considered, or abnormal situations are not taken into account, the theoretical capacity will be greater than the ideal capacity.
Cycle time is typically obtained through two methods: measurement and statistics. Measurement method: Use a stopwatch to measure the time it takes for the equipment to continuously produce a certain number of products. Divide the number of products by the measured time to get the cycle time. For example, if the equipment continuously produces 20 products and the measured time is 120 seconds, then the cycle time = 120/20 = 6 seconds. When using the measurement method, the more products produced, the more accurate the measurement result. Statistical method: Count the number of products produced by the equipment continuously for a period of time. Divide the number of products by the length of the statistical period to get the cycle time.
For example, if the equipment operates continuously and stably for 8 hours, producing 4800 units, then the production cycle time is 3600 * 8 / 4800 = 6 seconds. When using statistical methods, the longer the statistical period, the more accurate the measurement results. Measurement methods yield results closer to the equipment's theoretical production capacity, while statistical methods yield results closer to the equipment's actual production capacity. Measurement methods are relatively quick and simple, while statistical methods generally take longer and include more factors. Measurement methods are beneficial for equipment acceptance, while statistical methods are beneficial for production planning.
2) Actual production capacity
Actual (effective) capacity is the number of good products produced by the equipment per unit of time in actual production. Generally, when calculating actual capacity, the number of good products produced within a certain period is divided by the effective production time. For example, if the equipment produces 1800 products in one shift (8 hours), of which 1600 are good products, then the actual capacity of the equipment during this period is: Actual capacity = 1600/8 = 200 units/hour.
Methods to increase actual production capacity
(1) The actual production capacity is calculated based on the number of good products, which is the total number of products actually produced during the statistical period minus the number of defective products produced during that period. To improve the actual production capacity of the equipment, in addition to increasing the operating speed and efficiency of the equipment, it is also necessary to improve the product yield.
(2) Effective production time is the normal operating time of the equipment after deducting downtime. Equipment downtime (standby) includes equipment failure, waiting for materials, material replacement, etc. Therefore, to improve the actual production capacity of the equipment, it is also necessary to: improve the operating stability of the equipment, reduce the failure rate of the equipment, shorten the repair time of failure, and replenish materials in a timely manner to reduce downtime waiting for materials.
Methods to improve equipment operational stability
(1) From the perspective of equipment suppliers: a. Improve the reliability of the design in terms of structural design; b. Select reliable purchased parts; c. Improve the intelligence level of the equipment and monitor the material supply status and equipment operation status through sensors.
(2) From the perspective of the equipment user: a. Strengthen production management, and ensure production line capacity balance, timely material supply, and avoidance of defective products by means of lean management; b. Strengthen equipment management, and identify and eliminate potential equipment hazards in advance and replace vulnerable parts in a timely manner through equipment inspection and maintenance; c. Standardize operation, formulate detailed operating procedures (SOPs), and reduce equipment downtime caused by unfamiliarity with operation and improper operation. Usually, the capacity mentioned in the scheme specification and specifications refers to the theoretical capacity. The capacity required by the customer and the capacity accepted generally refers to the actual capacity. Therefore, attention should be paid when communicating with customers and signing contracts, and misunderstandings of customer requirements should be avoided. The actual capacity is generally lower than the theoretical capacity (ideal capacity), mainly depending on the stability of the equipment, the equipment yield, and is also affected by factors such as the proficiency of manual operation, the saturation of capacity allocation, and the material supply status of the previous process. Considering the factors of various downtime and defect rate, the theoretical capacity is generally 10-20% higher than the target capacity proposed by the customer during the design.
