Workpiece punctual production management method

Abstract

The invention discloses a workpiece punctualization production management method, which is realized through the following steps: step 1, collecting production data, and calculating target time of each process; step 2, inputting all numerical values involved in the step 1 and the calculated target time of each process into a monitoring data center for storage; 3, a workpiece code scanning station is arranged at each work station, each batch of materials to be fed into the work stations to be machined are packaged together, two-dimensional code labels for the workpiece code scanning stations to scan codes are pasted on the materials, the two-dimensional code labels are scanned during machining and after machining is completed, the code scanning time is sent to a monitoring data center, and the monitoring data center is used for monitoring the materials to be machined. And the monitoring data center obtains the actual processing time, and the actual processing time and all the data stored in the second step are displayed. Compared with the prior art, the management personnel can timely supervise the processing of each batch of materials by utilizing the target time independently researched and developed by the inventor, timely delivery can be ensured, and the problems of excessive stock and excessive production cannot be caused.

Description

Technical Field

[0001] The present invention relates to the field of production management, and in particular to a just-in-time production management method for workpieces. Background Art

[0002] Mass production refers to a production method that uses machines instead of manpower, special and efficient equipment and process equipment, and has a high degree of mechanization and automation in the production process, a high equipment utilization rate, a short production cycle, and easy protection of parts processing quality. For example, the existing mobile phone back cover needs to go through injection molding, sintering, shaping, post-processing and packaging inspection during production. Among them, the injection molding process has an injection molding station and a green embryo sandblasting station, the sintering process has a sintering plate station, a degreasing sintering station and a sintering blanking station, and the shaping process has a shaping station, a tapping station and a silver embryo sandblasting station. It can be seen that a workpiece needs to go through multiple process workshops during actual production, and each process workshop also has multiple stations with different processes. In this way, during production, each process workshop needs to be circulated, and each Turnover is also required between workstations, and during the turnover process, workers do not count the number of turnovers and the number of processes in progress. As a result, manufacturers purchase a large amount of materials after receiving an order, and then start production after purchasing the materials. The completion volume is counted based on the number of materials completed during the final inspection every day. After the actual production volume is completed, it is possible that other process workshops before the inspection will still have a certain amount of production, which will cause problems such as excessive inventory and overproduction. At the same time, the turnover time between each process and each workstation cannot be controlled, which makes it easy for delivery to be delayed during the production process.

[0003] In view of this, the inventor conducted in-depth research on the above-mentioned issues, which resulted in the present case. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a just-in-time production management method for workpieces to solve the existing problems of being unable to grasp the actual production status in time during the production of workpieces, resulting in excessive inventory, overproduction, and delayed delivery.

[0005] To achieve the above objectives, the present invention provides a method for managing just-in-time production of workpieces, which is implemented by the following steps:

[0006] Step 1: Collect production data and calculate the target time T for each process based on the customer's shipment requirements. The target time T is calculated as follows:

[0007] Step 1. Calculate the required takt time Ttak. The formula for calculating the required takt time Ttak is: Ttak = Twork1 / Pneed, where Twork1 refers to the actual working time of the equipment per day in seconds, and Pneed is the customer's actual shipment volume.

[0008] Step 2: Calculate the target hourly output Y_target. The formula for the target hourly output is: Y_target = P_required / T_working2, where T_working2 refers to the actual daily working hours of the equipment in hours.

[0009] Step 3: Calculate the total in-process quantity P_total_worker for each workstation. P_total_worker = P_in_process + P_between_processes, P_in_process = P_worker + P_waiting.

[0010] If the number of cavities in the current workstation is greater than 50, P_worker = M * P_theoretical_resource.

[0011] If the number of cavities in the current workstation is less than 50, P_worker = M * P_actual_resource. <000002**6>P_theoretical_resource = P_current_required * (1 + R) / P_single, P_current_required = P_next_required / Y_current, P_single = (3600 / CT) * η * T_working2, P_waiting = P_actual_resource * P_waiting_factor, P_between_processes = 3600 / (CT / P_actual_resource) / η / Y_once / (1 - R) * {(T_cycle + T_single_transfer) / 60} * (1 + TR), T_cycle = T_shift * N * 60;

[0013] Among them, P_in_process is the total quantity of in-process products within the process, P_between_processes is the total quantity of in-process products between processes, P_worker is the total quantity of in-process products in the current workstation, M refers to the number of cavities in all equipment within each workstation that can produce the same product, P_theoretical_resource refers to the theoretical resource value within the workstation, P_actual_resource refers to the actual resource value within the workstation. The resources within the workstation include human resources and equipment resources. When the equipment resources are not shared, and the human resources are shared or not shared, the actual resource value within the workstation is the ceiling of the theoretical resource value within the workstation. When the equipment resources are shared, and the human resources are shared or not shared, P_actual_resource = P_theoretical_resource. P_current_required refers to the production capacity quantity required by the current process, R refers to the re-inspection rate of the current workstation, P_next_required refers to the production capacity quantity required by the next process, Y_current refers to the production yield of the equipment in the current process, P_single refers to the production capacity quantity of a single person and a single machine, CT refers to the production time required for a single workpiece, η refers to the production efficiency of the equipment, P_waiting refers to the quantity of materials waiting in the workstation, P_waiting_factor refers to the quantity of products ready to be produced in the current workstation, Y_once refers to the one-time production yield of the equipment in the current workstation, T_cycle refers to the turnover interval time of the workpiece, T_shift refers to the working time of each shift, N refers to the number of turnovers occurring in each shift, T_single_transfer refers to the one-way turnover minutes of the workpiece from the previous process to the next process, and TR refers to the relaxation rate.

[0014] Step 4. Calculate the target time Tgo, Tgo = Tadditional time + Tsingle turn, Tadditional time = Pweek / Ystandard, Pweek = Ptotal1 + Ptotal2 + ... + Ptotaln, Tadditional time refers to the processing target of a process, Pweek refers to the total number of work-in-progress (WIP) of each station in a process, Ptotal1 refers to the total WIP of the first station in a process, Ptotal2 refers to the total WIP of the second station in a process, and so on. Ptotaln refers to the total WIP of the Nth station in a process;

[0015] Step 2: Input all the values ​​involved in step 1 and the calculated target time of each process into the monitoring data center for storage;

[0016] Step three, set up a workpiece scanning station at each workstation, which has a workpiece input scanning gun and a workpiece output scanning gun. The workpiece scanning station packs the quantity of each batch of materials to be sent to the workstation for processing together and affixes a QR code label for the workpiece scanning station to scan. During processing, the workpiece input scanning gun scans the QR code label and sends the scanning time to the monitoring data center. After processing, the workpiece output scanning gun scans the QR code label again and sends the scanning time to the monitoring data center. The monitoring data center calculates the difference between the two scanning times to obtain the time difference, which is the actual processing time. The monitoring data center displays this actual processing time and all the data stored in step two, and the specific data of the quantity of each batch of materials to be sent to the workstation for processing is the lowest common denominator of the quantity of materials to be processed in the current workstation.

[0017] The allowance rate for the above step 1 is 8%-10%.

[0018] In the above step 3, the monitoring data center displays all the data stored in step 2 in the form of a table, showing the target time of the same process and the actual processing time of each batch of materials in several batches of materials, the quantity of each batch of materials, the scanning time of the workpiece input into the scanner of each batch of materials, and the scanning time of the workpiece output from the scanner of each batch of materials in the same table.

[0019] After adopting the above technical solution, the invention provides a just-in-time production management method for workpieces. By utilizing the target time independently developed by the inventor, management personnel can timely supervise the processing of each batch of materials, timely adjust the turnover time between each process and each workstation, and ensure timely delivery. At the same time, the monitoring center can view the production capacity required for the current process in each process in real time. In this way, during processing, the current production quantity can be compared with the production capacity required for the current process to know how much production is needed for each process, which will not cause problems such as excessive inventory and overproduction. DETAILED DESCRIPTION

[0020] In order to further explain the technical solution of the present invention, the present invention is described in detail below through specific embodiments.

[0021] A just-in-time production management method for workpieces of the present invention is implemented by the following steps:

[0022] Step 1: Collect production data and calculate the target time T for each process based on the customer's shipment requirements. The target time T is calculated as follows:

[0023] Step 1. Calculate the demand takt time, Ttak. The formula for calculating the demand takt time, Ttak, is: Ttak = Twork1 / Prequired, where Twork1 refers to the actual daily working time of the equipment in seconds, Prequired is the customer's actual shipments, and Tactual = Twork1 / Pactual, where Pactual is the actual daily production volume. For example, if the customer's actual shipments are 65,000 units, and there are two shifts per day, each working 10 hours, the takt time is 1.1 seconds. This demand takt time is an important concept in lean production; it is the rhythm (output per unit time) that production must achieve to meet customer needs. It provides key insights into the calculation and management of work-in-process (WIP). It balances production cadence and WIP quantity. The demand tact defines the upper limit of production rate (e.g., one product must be completed every two minutes). By comparing the actual production tact with the demand tact, it can be used to determine whether there is an excess of WIP. When the actual tact is greater than the demand tact, production is too slow, potentially leading to a buildup of WIP (waiting downstream). When the actual tact is less than the demand tact, production is too fast, potentially causing excess inventory or waste. The demand tact can be used to adjust process balance, bringing the tact of each link closer to the demand tact and reducing WIP backlogs. The demand tact is the core basis for calculating and optimizing WIP. By comparing it with the actual production tact, it can be used to quantitatively analyze the rationality of WIP and guide waste elimination and flow balancing. The ultimate goal is to achieve efficient flow with "minimized WIP."

[0024] Step 2. Calculate the target hourly output (Ybold). The formula for calculating the target hourly output is: Ybold = Pneed / Twork2, where Twork2 refers to the actual daily working hours of the equipment in hours. That is, Ybold = 65,000 / 20 = 3,250. Therefore, the target hourly output of the workpiece is 3,250.

[0025] Step 3: Calculate the total number of work-in-progress at each workstation, Ptotal, where Ptotal = Pin + Pwait, Pin = Pwork + Pwait.

[0026] If the current number of workstations is greater than 50, Pwork = M*Pmanagement,

[0027] If the current number of workstations is less than 50, Pwork = M*Pactual Capital,

[0028] P handling capital = P current demand * (1 + R) / P order, P current demand = P later demand / Y current, P order = (3600 / CT) * η * T work 2, P waiting = P actual capital * P waiting, P time = 3600 / (CT / P actual capital) / η / Y one time / (1-R) ​​* {(T week + T order transfer) / 60} * (1 + TR), T week = T shift * N * 60;

[0029] Among them, Pin is the total number of work-in-progress in the process, Pinter is the total number of work-in-progress between processes, Pwork is the total number of work-in-progress in the current station, M refers to the number of holes in each station that can produce the same product by all equipment, Preal capital refers to the theoretical resource value in the station, and Pactual capital refers to the actual resource value in the station. The resources in the station include human resources and equipment resources. When equipment resources are not shared, human resources are shared, and not shared, the actual resource value in the station is equal to the theoretical resource value in the station rounded up. When equipment resources are shared, human resources are shared, and not shared, Pactual capital is equal to the theoretical resource value in the station rounded up. Capital = P management capital, P refers to the production capacity required by the current process, R refers to the retest rate of the current workstation, P refers to the production capacity required for the next process, Y refers to the equipment production yield of the current process, P refers to the production capacity of a single person and a single machine, CT refers to the time required to produce a single workpiece, η refers to the production efficiency of the equipment, P refers to the number of materials waiting in the workstation, P refers to the number of materials ready for production at the current workstation, Y refers to the one-time production yield of the equipment at the current workstation, T is the turnover interval of the workpiece, and T refers to the working time of each shift. , N refers to the number of turnovers in each shift, T single turn refers to the number of minutes of one-way turnover of the workpiece from the previous process to the next process, TR refers to the allowance rate; the allowance rate is 8%-10%, and the best one is 10%. The value of T single turn is timed by the worker using a stopwatch. The retest rate is actually determined according to the process, generally in the range of 0-0.3. The production efficiency of the equipment is the value of the equipment itself. The number of holes is the number of holes that all equipment in each workstation can produce the same product. For example, a workstation has 50 machines, and each machine has 10 molding chambers, that is, holes The number is 500. In the inspection process, the number of inspection stations on an inspection line is the number of holes. When calculating the production capacity required for the current process, the production capacity required for the next process must be calculated first. In this way, the production capacity of the last process (such as the inspection and packaging process) is calculated after P, which is the customer's actual shipment volume. For example, if the yield rate of the inspection and packaging process is 97%, the production capacity required for the inspection and packaging process is 65000 / 0.97=67010. By continuing to calculate upwards, the production capacity required for each process can be calculated.

[0030] Step 4. Calculate the target time T target, T target = T added target + T single turn, T added target = P week / Y standard, P week = P total 1 + P total 2 + ... + P total n, T added target refers to the processing target of a process, P week refers to the total WIP of each station in a process, P total 1 refers to the total WIP of the first station in a process, P total 2 refers to the total WIP of the second station in a process, and so on. P total n refers to the total WIP of the Nth station in a process. In the calculation of the total WIP of each station in a process, if a process has three stations, the sum of the total WIP of the three stations is used. If a process has only one station, the total WIP of that station is equal to the total WIP of the process;

[0031] Step 2: All the values ​​involved in step 1 and the calculated target time of each process are input into the monitoring data center for storage; Here, all the values ​​calculated in step 1 and the values ​​required for the calculation are input into the monitoring data center;

[0032] In step three, a workpiece scanning station is set up at each workstation. The workpiece scanning station has a workpiece input scanning gun and a workpiece output scanning gun. The quantity of each batch of materials to be sent to the workstation for processing is packaged together and affixed with a QR code label for the workpiece scanning station to scan. During processing, the workpiece input scanning gun scans the QR code label and sends the scanning time to the monitoring data center. After processing is completed, the workpiece output scanning gun scans the QR code label again and sends the scanning time to the monitoring data center. The monitoring data center calculates the difference between the two scanning times to obtain the time difference, which is the actual processing time. The monitoring data center displays this actual processing time and all the data stored in step two. The specific data of the quantity of each batch of materials to be sent to the workstation for processing is the lowest common denominator of the quantity of materials to be waited for in the current workstation. That is, if the quantity of materials to be waited for in the current workstation is 1260, then the quantity of each batch of materials to be sent to the workstation for processing can be 1260, 2520, etc.

[0033] At the same time, the data display of the monitoring data center in step three preferably displays all the data stored in step two in the form of a table, that is, the values ​​calculated in step one and the values ​​required for the calculation are all displayed in a table, and the data of all processes are displayed in a table, with the table as the parameter table, and then the target time of the same process and the actual processing time of each batch of materials in several batches of materials, the quantity of each batch of materials, the scanning time of the workpiece input of each batch of materials into the scanning gun, and the scanning time of the workpiece output of each batch of materials are all displayed in the same table, using this table as the monitoring table. In this way, the monitoring personnel can know the working time of each batch of materials and the processing data of all batches of materials in each process from the monitoring table, and then combine with the parameter table to immediately calculate the delivery time of the actual shipment required by the customer and the actual shipment and required shipment of each process in the actual shipment required by the customer, without causing problems of overcapacity and excessive inventory.

[0034] The present invention provides a just-in-time production management method for workpieces. By utilizing the target time independently developed by the inventor, management personnel can timely supervise the processing of each batch of materials, timely adjust the turnover time between each process and each workstation, and ensure timely delivery. At the same time, the monitoring center can view the production capacity required for the current process in each process in real time. In this way, during processing, the current production quantity can be compared with the production capacity required for the current process to know how much production is needed for each process, without causing problems such as excessive inventory and overproduction.

[0035] In the present invention, in order to facilitate management and viewing, data viewing in the monitoring data center can be viewed according to different processes and start times, and in the monitoring table, each batch of materials that exceeds the target time can be marked in red, those that are greater than 80% of the target time can be marked in green, and those that are less than 30% of the target time can be marked in blue. In this way, the monitoring personnel can see the current process processing at a glance.

[0036] The above embodiments do not limit the solutions of the present invention. Any appropriate changes or modifications made by ordinary technicians in the relevant technical field should be deemed to be within the patent scope of the present invention.

Claims

1. A just-in-time production management method for workpieces, characterized in that: It is achieved through the following steps: Step 1: Collect production data and calculate the target time T_target for each process according to the customer's shipping requirements. The calculation method of the target time T_target is as follows: Step 1: Calculate the required cycle time T_beat. The calculation formula for the required cycle time T_beat is: T_beat = T_working1 / P_required, where T_working1 is the actual daily working time of the equipment in seconds, and P_required is the actual shipping volume of the customer; Step 2: Calculate the target hourly output Y_target. The calculation formula for the target hourly output is: Y_target = P_required / T_working2, where T_working2 is the actual daily working time of the equipment in hours; Step 3: Calculate the total in-process inventory quantity P_total_worker for each workstation. P_total_worker = P_in_process + P_between_processes, P_in_process = P_worker + P_waiting, If the number of cavities in the current workstation is greater than 50, P_worker = M * P_theoretical_resource; If the number of cavities in the current workstation is less than 50, P_worker = M * P_actual_resource; P_theoretical_resource = P_current_requirement * (1 + R) / P_single, P_current_requirement = P_next_requirement / Y_current, P_single = (3600 / CT) * η * T_working2, P_waiting = P_actual_resource * P_waiting_factor, P_between_processes = 3600 / (CT / P_actual_resource) / η / Y_once / (1 - R) * {(T_cycle + T_single_transfer) / 60} * (1 + TR), T_cycle = T_shift * N * 60; Among them, P_in_process is the total in-process inventory quantity within the process, P_between_processes is the total in-process inventory quantity between processes, P_worker is the total in-process inventory quantity in the current workstation, M is the number of cavities of all equipment in each workstation that can produce the same product, P_theoretical_resource is the theoretical resource value in the workstation, P_actual_resource is the actual resource value in the workstation. The resources in the workstation include human resources and equipment resources. When the equipment resources are not shared and the human resources are shared or not shared, the actual resource value in the workstation is the ceiling of the theoretical resource value in the workstation. When the equipment resources are shared and the human resources are shared or not shared, P_actual_resource = P_theoretical_resource. P_current_requirement is the production capacity quantity required for the current process, R is the re-inspection rate of the current workstation, P_next_requirement is the production capacity quantity required for the next process, Y_current is the production yield of the equipment in the current process, P_single is the production capacity quantity of one person and one machine, CT is the production time required for a single workpiece, η is the production efficiency of the equipment, P_waiting is the material waiting quantity in the workstation, P_waiting_factor is the quantity prepared for production in the current workstation, Y_once is the one-time production yield of the equipment in the current workstation, T_cycle is the workpiece turnover interval time, T_shift is the working time of each shift, N is the number of turnovers occurring in each shift, T_single_transfer is the one-way turnover minutes of the workpiece from the previous process to the next process, and TR is the relaxation rate; Step 4: Calculate the target time T_target. T_target = T_processing_target + T_single_transfer, T_processing_target = P_cycle / Y_target, P_cycle = P_total_worker1 + P_total_worker2 +... + P_total_workern, T_processing_target is the processing target of a process, P_cycle is the total quantity of the total in-process inventory quantity of each workstation in a process, P_total_worker1 is the total in-process inventory quantity of the first workstation in a process, P_total_worker2 is the total in-process inventory quantity of the second workstation in a process, and so on. P_total_workern is the total in-process inventory quantity of the Nth workstation in a process; Step 2: Input all the values ​​involved in step 1 and the calculated target time of each process into the monitoring data center for storage; Step three, set up a workpiece scanning station at each workstation, which has a workpiece input scanning gun and a workpiece output scanning gun. The workpiece scanning station packs the quantity of each batch of materials to be sent to the workstation for processing together and affixes a QR code label for the workpiece scanning station to scan. During processing, the workpiece input scanning gun scans the QR code label and sends the scanning time to the monitoring data center. After processing, the workpiece output scanning gun scans the QR code label again and sends the scanning time to the monitoring data center. The monitoring data center calculates the difference between the two scanning times to obtain the time difference, which is the actual processing time. The monitoring data center displays this actual processing time and all the data stored in step two, and the specific data of the quantity of each batch of materials to be sent to the workstation for processing is the lowest common denominator of the quantity of materials to be processed in the current workstation.

2. A just-in-time production management method for workpieces according to claim 1, characterized in that: The allowance rate for the above step 1 is 8%-10%.

3. The just-in-time production management method of a workpiece according to claim 1, characterized in that: In the above step 3, the monitoring data center displays all the data stored in step 2 in the form of a table, showing the target time of the same process and the actual processing time of each batch of materials in several batches of materials, the quantity of each batch of materials, the scanning time of the workpiece input into the scanner of each batch of materials, and the scanning time of the workpiece output from the scanner of each batch of materials in the same table.