A Calculation Method for Batch Production Process Capability

Abstract

The present invention provides a method for investigating the process capability of mass production, which is based on the established production line and production program, based on the results of technological transformation, and aimed at the whole machine assembly test and parts manufacturing. According to the production mode of the production line and parts, relevant data collection, questionnaire design, actual production cycle calculation, equipment load rate measurement, process capability analysis, capacity short board analysis, etc. are carried out. By measuring and analyzing the specifications, the process capability short boards such as equipment and the lack of production resources such as tooling are supplemented, the lean manufacturing process is improved, and the purpose of improving the process capability and meeting the mass production requirements is achieved.

Description

Technical Field

[0001] The invention relates to a production process of a machinery manufacturing enterprise, and in particular to a method for investigating batch production process capability. Background Art

[0002] The calculation of production process capacity of machinery manufacturing enterprises is relatively complicated. The main reason is that there are many processing links for products, a large number of equipment involved in processing, and the equipment capacity does not change continuously, but develops in a step-by-step manner, so the processing capacity of each link is inconsistent. The calculation work usually starts from the bottom and proceeds from bottom to top. First, the capacity of a single device is calculated, and then the production capacity of the production line, workshop, and factory is calculated step by step. The calculation of production process capacity mainly includes two types: assembly line production type and batch processing production type. The main technical defects of the original technical solution are: first, the data collected by the survey is incomplete and inaccurate; second, the production process capacity of the mixed line production mode cannot be calculated; third, the supply capacity of outsourced products has not been analyzed, and the process capacity of the entire production line cannot be reflected. The above defects have caused the shortcomings of production capacity to be unclear, and it cannot be effectively used for capacity planning and production line construction for mass production of all products. Summary of the invention

[0003] In view of this, the present invention aims to propose a method for investigating the process capability of mass production, which is based on the established production lines and production guidelines, based on the achievements of technological transformation, and aimed at the whole machine assembly test and parts manufacturing. According to the production mode of the production lines and parts, relevant data collection, questionnaire design, actual production cycle calculation, equipment load rate calculation, process capability analysis, capacity shortcoming analysis, etc. are carried out. Through measurement and analysis, the process capability shortcomings of equipment and other equipment and the lack of production resources such as tooling are supplemented, the lean manufacturing process is improved, and the purpose of improving process capability and meeting mass production is achieved.

[0004] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0005] A method for investigating batch production process capability, the method comprising the following steps:

[0006] 1) For the products to be investigated, investigate and count the names, drawing numbers, materials, production lines or production units, cooperative units, number of units / batches and single-piece production cycles of multiple varieties of self-made parts, and draw a production process capability information table for special parts;

[0007] 2) Investigate and count the names, drawing numbers, materials, manufacturers, quantities of units / batches, and delivery cycles of multiple types of purchased standard parts, and draw up a production process capability information table for purchased standard parts;

[0008] 3) Investigate and count the names, drawing numbers, materials, outsourcing manufacturers, quantity of units / batches and delivery cycles of multiple types of outsourced parts, and draw up a production process capability information table for purchased parts;

[0009] 4) Investigate and count the names, material grades, manufacturers, unit / batch quantities, unit quotas and unit delivery cycles of raw materials such as round steel and plates required for various types of parts, and draw a production process capability information table for raw materials;

[0010] 5) Investigate and count the names, material grades, single-piece delivery cycles and yield rates of the forming blanks required for various types of parts, to analyze the process capability of blank forming and draw a production process capability information table for blank forming;

[0011] 6) Investigate and count the models, component assembly cycles, component test cycles, whole machine assembly cycles and whole machine test cycles of assembly tests of multiple products, and draw a production process capability information table for assembly tests;

[0012] 7) According to the existing manufacturing process regulations of the parts, investigate and count the process equipment required for the manufacturing process, collect the number of cutting tools, auxiliary tools, measuring tools, fixtures, tools, the accuracy and cost of tooling, and the manufacturing source of the process equipment, so as to analyze the rationality and completeness of the configuration of the process equipment, improve the correctness of the manufacturing process, enhance the manufacturing process capability, and draw a process equipment information table;

[0013] 8) Calculate the production cycle, including single-piece production cycle or supply cycle, batch production cycle or supply cycle;

[0014] 9) Calculate equipment load rate;

[0015] Using a three-shift workday, taking into account the rest and preparation time of production personnel, it is calculated as 23 hours. Excluding rest days and equipment maintenance and overhaul days, the annual working days are calculated as 251 days. Generally, the load rate of a piece of equipment is ≤85%;

[0016] In order to reflect the equipment conditions under the bad production conditions, the equipment load rate is calculated on a monthly basis. The calculation formula is: Equipment load rate = [monthly workbench hours / (251×23)÷12]×100%;

[0017] 10) Analyze production process capabilities, identify shortcomings in production capacity and manufacturing resources, and form a comprehensive survey information table on production process capabilities of a certain model of product;

[0018] 11) Find out the existing problems in the comprehensive survey information table obtained in step 10), formulate measures such as supplementing equipment, optimizing process equipment, improving process flow, etc. according to the problems, prepare a production line construction plan, report it to relevant departments for implementation, and ultimately achieve the purpose of reducing cycle time, improving quality, and improving efficiency;

[0019] 12) According to the improved production line and supplementary process resources, the production process capability shall be verified. The verification method may be first article inspection or process verification;

[0020] 13) After verification and effectiveness are achieved, improve the on-site process procedures.

[0021] Furthermore, the single-piece production cycle or supply cycle of the parts is calculated based on the statistical data in the table obtained from steps 1)-4) and step 8), that is, the first-piece production or supply cycle, which is the number of production hours required for the first piece to be produced from the beginning to the final transfer out of the unit, to determine the tact time of single-piece manufacturing or supply. For the convenience of statistics, the collaborative processing time of the intermediate transfer out of the unit is not included here.

[0022] Furthermore, the batch production cycle or supply cycle is calculated based on the statistical data in the table obtained in steps 1)-4) and step 8). Since the balanced production organization mode is taken into account, the batch quantity is counted by month, and its batch quantity production cycle or supply cycle is the monthly production quantity (i.e. the total number of annual batches divided by 12), and the number of production hours required from the start of production to the final transfer in this unit;

[0023] The calculation formula is: first piece production cycle or supply cycle + (monthly production quantity - 1) × cycle time, where the cycle time is defined as the number of hours of the longest process in the processing of the first piece.

[0024] Furthermore, step 10) analyzes the production process capability by calculating and analyzing the number of single-unit wearing parts and the number of batch wearing parts required by product design, and determines the spare part rate of the annual batch products required for wearing parts; determines the scrap rate of the blank forming, machining, heat treatment and other links by calculating and analyzing the data of the actual output cycle of parts; and determines the equipment's machine-hour loss rate by calculating and analyzing the equipment load rate and machine-hours.

[0025] Further, step 11) is specifically as follows: according to the actual production quantity and the actual output qualified product quantity of the scrap rate calculation process obtained in the table of step 10), the production cycle of the product is obtained, and according to the non-conformity of the production cycle, the problems in the self-made parts, purchased parts, outsourced parts, blank forming, raw materials, process equipment, assembly testing and other links are found out.

[0026] Compared with the prior art, the method for investigating batch production process capability of the present invention has the following advantages:

[0027] The method for investigating the batch production process capability described in the present invention is a method for investigating the process capability of mixed-line batch production of multiple varieties and models of engines. The method investigates the product manufacturing conditions undertaken by different production lines and different production units, draws a survey information table, and then calculates the production cycle, equipment load rate, etc., analyzes the calculated data, finds out the shortcomings and problems that restrict batch production, forms a survey report and feeds back to the relevant departments. The relevant departments have planned improvement methods for the problems, and achieved the purpose of improving process capability and meeting batch production on the basis of process verification. By applying this survey method to the survey of batch production of all models of engines, the effect is very good, forming an engine batch production process capability survey method based on lean management, optimizing the process flow and process equipment, and formulating process design standards and specifications suitable for batch production, laying a solid foundation for the company's batch production and future product development. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0029] Figure 1 The present invention is a flowchart of a method for investigating batch production process capability according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0031] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0032] According to the various types of tank and armored vehicle engines and the fact that the original engines are not well serialized and have low versatility, we collect data on the process capabilities of each component, calculate data, analyze capabilities, identify shortcomings, supplement shortcomings, build capabilities, verify capabilities, and improve processes.

[0033] The research method includes the following steps:

[0034] 1. According to the annual production program, investigate and count the names, drawing numbers, materials, production lines or production units, cooperative units, number of units / batches and single-piece production cycles of various self-made parts, and draw a production process capability information table for special parts. See Table 1.

[0035] 2. According to the annual production program, investigate and count the names, drawing numbers, materials, manufacturers, quantities of units / batches, and delivery cycles of multiple types of purchased standard parts, and draw a production process capability information table for purchased standard parts. See Table 2.

[0036] 3. According to the annual production program, investigate and count the names, drawing numbers, materials, outsourcing manufacturers, quantity of units / batches and single-piece delivery cycles of various outsourced parts, and draw a production process capability information table for outsourced parts. See Table 3.

[0037] 4. According to the annual production program, investigate and count the names, material grades, manufacturers, unit / batch quantities, unit quotas and unit delivery cycles of raw materials such as round steel and plates required for various types of parts, and draw a table of production process capacity information for raw materials. See Table 4.

[0038] 5. According to the annual production program, investigate and count the names, material grades, single-piece delivery cycles and yield rates of the forming blanks required for various types of parts, so as to analyze the process capability of blank forming and draw a production process capability information table for blank forming. See Table 5.

[0039] 6. According to the annual production program, investigate and count the models, component assembly cycles, component test cycles, whole machine assembly cycles and whole machine test cycles of assembly tests of various products, and draw a production process capability information table for assembly tests. See Table 6.

[0040] 7. According to the existing manufacturing process regulations of the parts, investigate and count the process equipment required for the manufacturing process, collect the number of cutting tools, auxiliary tools, gauges, fixtures, tools, the accuracy and cost of tooling, and the manufacturing source of the process equipment, so as to analyze the rationality and completeness of the configuration of the process equipment, improve the correctness of the manufacturing process, enhance the manufacturing process capability, and draw a process equipment information table. See Table 7.

[0041] 8. Calculate production cycle

[0042] For special production lines, such as large-scale component bodies, cylinder heads, etc., the processes are rationally designed according to batch production to form assembly line operations; for mixed production lines, such as gears, special shaped parts, etc., the production plan fully considers the balanced organization of production mode, disperses the rough and fine processes, and calculates in order to open up the production line mode.

[0043] (1) Single piece production cycle or delivery cycle

[0044] According to the statistical data in Tables 1-4 and 8, calculate the single-piece production cycle or supply cycle of parts, that is, the first-piece production or supply cycle, which is the number of production hours required for the first piece from the beginning of production to the final transfer in this unit, and determine the tact time of single-piece manufacturing or supply. For the convenience of statistics, the collaborative processing time of the intermediate transfer in this unit is not included here.

[0045] (2) Mass production cycle or supply cycle

[0046] According to the statistical data in Tables 1-4 and 8, the batch production cycle or supply cycle of parts is calculated. Since the balanced production organization mode is taken into account, the batch quantity is counted by month, and the batch production cycle or supply cycle is the monthly production quantity (i.e. the total annual batch quantity ÷ 12), and the production hours required from the start of production to the final transfer in this unit. The calculation formula is:

[0047] First piece production cycle or supply cycle + (monthly production quantity - 1) × cycle time

[0048] The cycle time is defined as the number of hours it takes for the first piece to be processed in the longest process.

[0049] 9. Calculate equipment load rate

[0050] The three-shift workday is used, and the rest and preparation time of production personnel is taken into account, and the calculation is based on 23 hours. Excluding rest days and equipment maintenance and overhaul days, the annual working days are calculated as 251 days. Generally, the load rate of a piece of equipment is ≤85%. In order to reflect the equipment status under the harsh production conditions, the equipment load rate is calculated on a monthly basis, and the calculation formula is:

[0051] Equipment load rate = [monthly workbench hours / (251×23)÷12]×100%

[0052] 10. Analyze production process capabilities

[0053] By calculating and analyzing the number of single and batch wearing parts required by product design, the spare parts rate of wearing parts required for batch products throughout the year is determined; by calculating and analyzing the data of the actual output cycle of parts, the scrap rate of blank forming, mechanical processing, heat treatment and other links is determined; by calculating and analyzing the equipment load rate and machine hours, the machine hour loss rate of the equipment is determined. Through the above comprehensive analysis, the shortcomings of production capacity and manufacturing resources are found, and a comprehensive survey information table of production process capacity of a certain model of product is formed. See Table 8.

[0054] 11. According to the actual number of put into production and the actual number of qualified products output in the scrap rate calculation process in Table 8, the production cycle of the product is obtained. According to the non-conformity of the production cycle, the problems in self-made parts, purchased parts, outsourced parts, blank forming, raw materials, process equipment, assembly testing and other links are found out. According to the problems, measures such as supplementing equipment, optimizing process equipment, and improving process flow are formulated. A production line construction plan is prepared and reported to relevant departments for implementation, ultimately achieving the goal of reducing cycle time, improving quality and increasing efficiency.

[0055] 12. According to the improved production line and supplementary process resources, the production process capability shall be verified. The verification method can be first-article inspection or process verification.

[0056] 13. After verification and achieving the desired results, improve the on-site process procedures.

[0057] Table 1 Production process capability information for producing special parts

[0058]

[0059] Table 2 Production process capability information of purchased standard parts

[0060]

[0061] Table 3 Production process capability information table of purchased parts

[0062]

[0063] Table 4 Raw materials production process capability information

[0064]

[0065] Table 5 Production process capability information table for blank forming

[0066]

[0067]

[0068] Table 6 Production process capability information table for assembly test

[0069]

[0070] Table 7 Process equipment information

[0071]

[0072]

[0073] Table 8 Comprehensive information table of production process capability of a certain type of engine

[0074]

[0075] In addition, the following research principles need to be followed during the research process:

[0076] 1. Based on the performance parameters of existing equipment and equipment to be purchased, as well as the material of the processing object, efficient processing is the principle; the optimized cutting parameters of various tools on related equipment are used as a reference for processing measurement.

[0077] 2. Determine the batch production process plan and process equipment for self-made parts, follow the principles of high efficiency and high quality, separate the processing steps into rough and fine steps as much as possible, and form assembly line operations.

[0078] 3. For the clamping of parts, try to choose convenient and quick fixtures, mainly combined fixtures and supplemented by special fixtures. In particular, the fixtures on the machining center should fully consider the versatility and grouping.

[0079] 4. When selecting processing tools, on the premise of ensuring quality, they should be matched with existing equipment, fully consider processing efficiency, and try to use domestic standard tools as the main tool, supplemented by foreign purchases.

[0080] 5. For machining centers with long tool adjustment and measurement time, a "tool pre-adjustment station" has been established to reduce equipment load rate and improve production efficiency.

[0081] 6. Take corresponding solutions to the problems found during the research process. Feedback on the processability, "three transformations" and management issues of product design was given to the design department and relevant management departments, providing a reliable basis for improvement in model design finalization and mass production organization.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for calculating batch production process capability, characterized in that: The method comprises the following steps: 1) For the products to be investigated, investigate and count the names, drawing numbers, materials, production lines or production units, cooperative units, number of units / batches and single-piece production cycles of multiple varieties of self-made parts, and draw a production process capability information table for special parts; 2) Investigate and count the names, drawing numbers, materials, manufacturers, quantities of units / batches, and delivery cycles of multiple types of purchased standard parts, and draw up a production process capability information table for purchased standard parts; 3) Investigate and count the names, drawing numbers, materials, outsourcing manufacturers, quantity of units / batches and delivery cycles of multiple types of outsourced parts, and draw up a production process capability information table for purchased parts; 4) Investigate and count the names, material grades, manufacturers, unit / batch quantities, unit quotas and unit delivery cycles of round steel and plate raw materials required for various types of parts, and draw up a production process capability information table for raw materials; 5) Investigate and count the names, material grades, single-piece delivery cycles and yield rates of the forming blanks required for various types of parts, to analyze the process capability of blank forming and draw a production process capability information table for blank forming; 6) Investigate and count the models, component assembly cycles, component test cycles, whole machine assembly cycles and whole machine test cycles of assembly tests of multiple products, and draw a production process capability information table for assembly tests; 7) According to the existing manufacturing process regulations of the parts, investigate and count the process equipment required for the manufacturing process, collect the number of cutting tools, auxiliary tools, gauges, fixtures, tools, the accuracy and cost of tooling, and the manufacturing source of the process equipment, so as to analyze the rationality and completeness of the configuration of the process equipment, improve the correctness of the manufacturing process, enhance the manufacturing process capability, and draw a process equipment information table; 8) Calculate the production cycle, including single-piece production cycle or supply cycle, batch production cycle or supply cycle; 9) Calculate equipment load rate; The three-shift workday is adopted. Taking into account the rest and preparation time of production personnel, it is calculated as 23 hours. The annual working days are calculated as 251 days excluding rest days and equipment maintenance and overhaul days. The load rate of a piece of equipment is stipulated to be ≤85%; In order to reflect the equipment conditions under the bad production conditions, the equipment load rate is calculated on a monthly basis. The calculation formula is: Equipment load rate = [monthly workbench hours / (251×23)÷12]×100%; 10) Analyze production process capabilities, identify shortcomings in production capacity and manufacturing resources, and form a comprehensive survey information table on production process capabilities of a certain model of product; 11) Find out the existing problems in the comprehensive survey information table obtained in step 10), formulate measures to supplement equipment, optimize process equipment, improve process flow according to the problems, prepare production line construction plan, report to relevant departments for implementation, and ultimately achieve the goal of reducing cycle time, improving quality and increasing efficiency; 12) Carry out production process capability verification according to the improved production line and supplementary process resources, and the verification method shall be first article inspection or process verification; 13) After verification and achieving the desired results, improve the on-site process procedures; The single-piece production cycle or supply cycle is calculated based on the statistical data in the table obtained in steps 1)-4) and step 8), that is, the first-piece production or supply cycle, which is the number of production hours required for the first piece from the start of production to the final transfer in this unit, to determine the tact time of single-piece manufacturing or supply. For the convenience of statistics, the collaborative processing time of the intermediate transfer in this unit is not included here; The batch production cycle or supply cycle is calculated based on the statistical data in the table obtained in steps 1)-4) and step 8). Since the balanced production organization mode is taken into account, the batch quantity is counted by month, and the batch quantity production cycle or supply cycle is the monthly production quantity, that is, the total annual batch quantity divided by 12, and the number of production hours required from the start of production to the final transfer in this unit; The calculation formula is: first piece production cycle or supply cycle + (monthly production quantity - 1) × cycle time, where the cycle time is defined as the number of hours of the longest process in the processing of the first piece; Step 10) Analyze production process capabilities. Determine the spare parts rate of the annual batch products required for wearing parts by calculating and analyzing the number of wearing parts per unit and the number of wearing parts in batches required by product design; determine the scrap rate of blank forming, machining and heat treatment by calculating and analyzing the data of the actual output cycle of parts; determine the equipment's hourly loss rate by calculating and analyzing the equipment load rate and hourly hours.

2. The method for calculating the batch production process capability according to claim 1, characterized in that: Step 11) is specifically as follows: According to the actual production quantity and the actual output qualified product quantity of the scrap rate calculation process obtained in the table of step 10), the production cycle of the product is obtained; according to the non-conformity of the production cycle, the problems in the self-made parts, purchased parts, outsourced parts, blank forming, raw materials, process equipment, and assembly test links are found out.

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