Design of monitoring system for the hottest tighte

Design of monitoring system for tightening assembly line

at present, several key processes in engine assembly in major domestic automobile factories, such as the assembly of oil pan and upper cover, have generally adopted fully automatic multi shaft tightening machines. The tightening machine is installed on the slide. A PLC controls the start and stop of the conveyor belt, the positioning of the workpiece, the expansion and contraction of the slide and the start of the tightening machine. The whole tightening process is independently controlled by the computer in the tightening machine according to the preset process parameters. The main problem of this system is that it is difficult to adjust the process parameters, cannot carry out fast and accurate quality analysis, and is difficult to carry out comprehensive and effective production management and statistical management. In view of the above problems, the author designed a tightening machine monitoring and management system for the second engine plant of FAW Group. With the help of the multi task ability of Windows operating system, an industrial computer was used to monitor and manage the two tightening assembly lines of oil pan and upper cover, which better solved the above problems. The system has been in normal operation since 1997

1 system hardware composition

this system takes a 486 industrial computer as the core, and is connected with two tightening machines through two photoelectric isolation RS232 current ring serial ports. The basic configuration of hardware is as follows:

industrial computer:

① 486dx100cpu

② 8m ram

③ 850m HD

④ 3 FD

open the electromechanical start tension experiment ⑤ 2 Series 1 parallel communication ports

⑥ keyboard and mouse

⑦ VGA color CRT

a 500W UPS power supply

a Chinese and English graphic printer

the system composition block diagram is shown in Figure 1

Figure 1 system composition block diagram

2 system functions

the design objectives of this system are:

(1) tightening process parameter setting

(2) dynamic tracking of tightening torque curve

(3) storage of tightening results of all workpieces

(4) analyze the quality distribution and quality trend of the workpiece within the optional range

(5) statistical analysis of annual and monthly output and qualification rate

(6) query the operation records of any workpiece and any team

the system software has powerful functions and is an effective tool for the factory to carry out all-round quality management. Its core is the workpiece database management system

in order to achieve the above design goals, the system sets up several groups of functional menus, such as system management, parameter management, curve management, quality management, statistical management and team management. The main screen of the software system is shown in Figure 2

Figure 2 Schematic diagram of the main window of the system

the system software adopts the windows multi window design technology. The main window provides the system function menu, and several sub windows display the tightening operation of each equipment. In the lower part, a status window displays the on duty output, qualification rate and time of each equipment. The tightening result window of each equipment is overlapped. The system function menu is common to all devices, and the operation object is the device corresponding to the top-level window. To operate a device, just turn its corresponding window into the top-level window. This system has many functions. There are usually multi-level submenus under the top-level menu. After selecting each menu, the corresponding dialog box will generally appear to instruct the user to make necessary selections or inputs. After confirmation, the system will perform the response function

2.1 system management

under this menu, there are only two functions: system password modification and operator list modification

this system implements password protection for the tightening parameter modification and tightening result modification (for repaired parts) functions to be introduced later. The password modification function provides a means to modify the password when necessary. This function is the same as the old password approval and new password input dialog boxes in general systems

the function of modifying the operator list is set for team management. With this function, the system administrator can set and modify the operator list of each shift of each equipment for the operator to choose his own name when taking over the shift. The list of operators is stored in a separate file

2.2 parameter management

the process parameters of each tightening machine in this system can be modified on site and on the management machine respectively. If the operator modifies parameters on site, the administrator will receive a notification message and automatically send the modified parameters to the management machine for storage. The administrator can also modify the process parameters of each equipment on this machine and send them down to the tightening machine to make it work immediately. Due to the importance of process parameters, whether modifying parameters on site or on the management machine, password verification is required. The process parameters are updated synchronously on the tightening machine and the management machine, and the rationality of the parameters is checked. The process parameters of each equipment are stored on the disk in the form of documents and serve as the standard for the manager to judge whether the tightening result is qualified

2.3 curve management

this system provides the function of continuously tracking, displaying, storing and printing the torque/time curve and torque/angle curve (for the system with angle control) of any axis of each tightening machine, and sets the functions of displaying, printing and deleting the stored curve. This function is a powerful tool for adjusting process parameters and analyzing the quality of screw holes and bolts

to track the curve, first select the equipment number and shaft number. After confirmation, the torque/time curve and torque/angle curve (for systems with angle control) display window as shown in Figure 3 will appear, which is equipped with a storage and print menu. For the storage curve display function, there is a print and delete function menu

Figure 3 torque/time curve display window

as the tightening process proceeds, the window will draw the tracking curve in real time. After tightening, the final torque value and angle value will be displayed above the curve. At this time, if you want to view the torque value at any time during the tightening process, just move the mouse horizontally on the torque/time curve window, and the torque value and time value corresponding to the time of the mouse can be displayed on the window. If you want to view the torque value corresponding to a certain angle (for systems with angle control), just move the mouse horizontally on the torque/angle curve window to view the torque value at any angle

typical curves can be stored on disk or printed out

2.4 quality management

the quality management function menu includes four items: quality distribution histogram, quality trend chart, workpiece information query and workpiece data modification. The realization of these functions depends on the workpiece database system of this system

the system establishes its own workpiece database for each tightening machine, each workpiece corresponds to a record, and each database has a main index file and several sub index files. The structure of the workpiece database system of this system is specially designed, so that the database only contains the torque value and angle value of the workpiece, while the accessory information of the workpiece such as processing time, operator and whether it is qualified are included in the index file. In this way, the database occupies less disk, and the hard disk can store the workpieces that can be processed by two devices for ten years. For the statistical function, you only need to query the index file, so that the statistical work is very fast

this database system provides two query methods based on workpiece number and time/team, which support quality management, statistical management and team operation information query respectively

the mass distribution histogram adopts the torque range method to analyze the torque value distribution of several groups of continuous samples within the specified workpiece serial number range according to the statistical theory and express it in the form of histogram. Statistical data such as UCL, LCL, CP, Cpk, mean value and range are also displayed at the bottom of the figure for users' reference. It should be pointed out that the quality analysis is carried out for the single axis, while the statistical analysis (output and qualification rate) is carried out for the workpiece

to analyze the quality distribution, first select the equipment number and axis number, and then enter the starting workpiece number, group number and sample number of each group. After confirmation, the system will display the quality distribution histogram window as shown in Figure 4 after query and calculation

Figure 4 quality distribution histogram window

the system provides the group number of 7 to 25 and the sample number of each family of 7 to 25 according to the conventional statistical theory. The quality distribution analysis is carried out according to the torque range method. This figure can help the technician make an accurate judgment on the repetition accuracy of the equipment and the quality of the workpiece

quality trend is to use the torque range method to analyze the torque value trend of several groups of continuous samples within the specified workpiece serial number range according to the statistical theory and show it in the form of trend graph. Statistical data such as UCL, LCL, CP, Cpk, mean value and range are also displayed at the bottom of the graph for users' reference

to analyze the quality distribution, first select the equipment number and shaft number, and then enter the starting workpiece number, group number and sample number of each group. After confirmation, the system will display the quality trend chart window as shown in Figure 5 after inquiry and calculation

Figure 5 quality trend chart window

this figure shows the change of the average torque of each group of samples. The technologist can adjust the parameters of the tightening machine in time according to the possible abnormal conditions such as continuous rise, continuous fall, and average overrun in the figure, so as to avoid quality accidents

the workpiece information query function provides the query of all the information of any workpiece. After specifying the equipment number and workpiece number, the system will display the workpiece information query dialog box as shown in Figure 6

Figure 6 workpiece information query dialog box

workpiece data saving and low-carbon Qinghai waste asphalt pavement materials significantly improve the benefits of geothermal regeneration technology. The appearance of the dialog box is the same as Figure 6, but after password verification, it is allowed to modify torque and angle values. This function is set for the repair of unqualified parts

2.5 statistical management

statistical management is mainly to count the annual, quarterly and monthly output and qualification rate of each equipment and shift, and display and print them in the form of statements and histograms. Since these tables are large, we will skip them here

2.6 team management

the team management function menu includes three functions: new shift handover, current shift handover and team operation information query

in order to ensure the data integrity of the database information, the system stipulates that the shift must be taken over on the management machine before the operation, and the shift must be handed over on the management machine after the operation, and the new shift cannot take over before the previous shift. Shift succession mainly refers to the selection of equipment, shifts and operators, and shift handover mainly refers to the confirmation of the operation record information of the shift

in order to carry out all-round quality and production management, the system has set up the function of team operation information query. After selecting the equipment number, operation time and shift, the system will display the shift operation information dialog box as shown in Figure 7

Figure 7 team operation information query dialog box

Jinan new era Gold Testing Instrument Co., Ltd. is a nationally renowned enterprise. This system integrates the functions of process preparation, production process monitoring, quality control and statistical reports. It is a powerful tool for the factory to carry out all-round quality management. After practical application in FAW No. 2 engine plant, the effect is very good