Safety improvement of manual operation stamping production line for body panels

With the rapid development of China's automobile industry, the level of industrial technology and automation related to automobile production has been continuously improved. At present, domestic independent automobile manufacturers such as Great Wall, Chery, BYD, Jianghuai, Geely and Lifan have introduced advanced production technology and technology. As far as the first stamping production line of the four major processes of automobile manufacturing is concerned, some domestic manufacturers have been upgraded and established an automated stamping production line operated by robots, but the price is not high, and millions of yuan has been invested. There are still some automobile OEMs in China. Retain or build a manually operated press line.

In recent years, people's awareness of personal safety protection has been continuously strengthened. The state has also emphasized the safety of production. Although there are many safety measures for stamping production, the stamping workers are still high-risk occupations. In all kinds of mechanical equipment injury accidents, the proportion of injuries caused by stamping equipment is the largest. According to Wang Weizhen’s "Discussion on Safety Technology of Mechanical Presses", serious accidents caused by stamping operations generally account for the total number of serious accidents. About 50%, of which about 38% occurred due to the feeding, about 20% due to the correction of the processing parts, due to cleaning of the scrap or other foreign matter of about 14%, multi-person operation is not coordinated or the mold installation adjustment is improper Accounted for 21%, the rest is caused by mechanical failure. Therefore, ensuring personal safety in manual operation makes the manager's responsibility pressure very high. It can be seen that the safety protection measures of the stamping manual operation line are extremely important.

1. Basic situation and defect analysis

(1) Status of safety measures China Chongqing Lifan Passenger Vehicle Co., Ltd. currently has three body covering stamping production lines, two of which are presses for hydraulic presses that are forged and forged, and one for hydraulic presses for day forging. The safety standard of the manual press line of the hydraulic press is equipped with four emergency stop buttons for each of the four columns (for emergency situations), two emergency stop buttons for the two consoles (for emergency situations), and a set of safety for the opposite corners of the slider Bolt (used when needed to enter the mold and the middle of the workbench), install a set of on-beam photoelectric protection device (for delineating the safety red line) and four slider locking pin devices (for loading and unloading molds, repairing molds, etc.).

(2) Defect analysis From the analysis of a series of safety accidents in the stamping industry and the safety defects exposed during our use, the possible safety defects are as follows: 1 The number of emergency stop buttons is insufficient, and the machine maintenance is not considered. In the state, the personal safety of the maintenance personnel. 2 "Vertical fixed" installation photoelectric protection device has a limited protection range, and the protection area is a vertical line, and no horizontal protection surface or three-dimensional protection is formed. 3 In the case of the machine tool pressing small mold, some parts of the workbench are used to protect the vacuum zone. When there is a person entering and no one is found, the operation machine will go down, which will cause a major accident. 4 There is no clear signal to confirm that the personnel have exited the dangerous area. Only relying on the operator to observe, when the observation is not complete, it is prone to misuse and threaten personal safety.

2. Improvement measures

In view of the defects and shortcomings of the safety protection measures for the above-mentioned stamping production manual operation line, we have made some improvements and proposed the following measures.

(1) For the shortage of emergency stop button, we install an emergency stop button in the maintenance platform area, which is mainly used to press the button in the maintenance state of the equipment, and the machine cannot be started to protect the personal safety of the maintenance personnel, as shown in Figure 1. Shown.

(2) According to the employee's operation of the walking route, the original photoelectric protection device is installed from the vertical installation to the horizontal installation to form a “horizontal” protection surface, which constitutes the three-dimensional protection belt in the area. In this protection zone, as long as there are people or foreign objects in this area, the photoelectric protection device will start, limiting the machine tool to descend, as shown in Figure 2.

(3) For the installation of small molds with dimensions much smaller than the working surface of the hydraulic machine, we install a set of photoelectric protection devices that can be adjusted back and forth, as shown in Figure 3.

(4) In order to facilitate the confirmation of the feedback signal when there is no personnel or foreign objects in the work area, a button is added to each of the four columns of the machine tool for feedback that the operator has exited the mold and the dangerous working area of ​​the machine tool, so that only the employees After pressing the 4 buttons, the machine can operate the downward pressing of the workpiece, as shown in Figure 4.

3. Conclusion

Through the analysis and improvement of the company's current stamping manual operation line safety measures, it reduces the safety hazards in production, reduces the occurrence of safety accidents, and realizes the comprehensive three-dimensional protection for maintenance personnel and operators. The above improvement measures have been successfully applied to Lifan. In the safety protection of the manual operation production line of the stamping workshop of Passenger Vehicle Co., Ltd., and achieved good results, it was affirmed by the company's leaders and employees, which brought great significance and guarantee for the company's profitable production.

The technical reform won the “Creative Kung Fu Award” and “Equipment Technology Improvement Award” within Lifan Group in 2013, and was promoted and used in the stamping production line of other business units within the Group.

About the author: Li Xiaoming, Ren Guoqiang, Sichuan Vocational and Technical College. Longhui, Chongqing Lifan Passenger Vehicle Co., Ltd., stamping workshop.