Research on the switching between the sealing and non sealing state of automobile panel die

Poor surface quality of window sealing parts
Fig. 3 suction cup shape of end effector
After the mold is switched from the normal part state to the window sealing part state, the inner part of the product window frame will have different degrees of crush defects, as shown in Fig. 4. This kind of crush defect is caused by the local bulge of the blank plate, which is used for pressing materials in the process of trimming and flanging under normal conditions. The window position of the window sealing parts belongs to area a, and the quality requirements are relatively high, and there are no problems such as crushing, concave convex and so on. Therefore, it is necessary to solve the crush problem of the parts in the sealed window state, so that the mold can take into account the production of the parts in the sealed window and the conventional state.
Figure 4 part crush problem
The method to solve this problem is: apply a layer of blue oil (the thickness is usually about 0.03mm) with a brush on the front and back sides of the parts, and conduct a pressure test on the die testing press according to the normal production parameters. By observing the blue oil coloring on the pressing plate of the parts and the die after the pressure test, we can judge whether the parts and the die surface are completely matched. After that, the white spots on the front and back sides of the parts are properly polished, and polished with oilstone and sandpaper. Then repeat the above steps again until the blue oil coloring is uniform without obvious whitening. In order to ensure the smoothness of the coloring surface, the color width of trimming and punching process is usually 20 mm, and that of flanging process is 30 mm. The shaping process needs to consider the deformation of the parts, the pressing force and the surface quality of the product, which usually has a larger coloring width than the blank side of trimming and flanging. The uniform blue oil coloring means that the gap between the blank plate and the parts is uniform, so that the pressing force can be evenly distributed on the whole coloring surface, and the parts in the production window sealing state will not be locally crushed by the pressing plate, and at the same time, it can play a good role in pressing materials for the parts in the conventional state.
Fig. 5 uniform color matching
It is easy for the operator to install the mould parts by mistake and miss
In the process of window sealing and normal state switching, it is necessary to disassemble and assemble the die structure and insert. There are many die inserts and screws which are similar, so it is easy to have problems such as wrong installation and missing installation. Once the mold is produced, if there is wrong assembly and missing assembly, the quality of the parts will be unqualified, and the mold may be crushed seriously. In order to ensure the correct disassembly and assembly of each mold, the following measures are taken.
(1) the best way is to set error proofing on the mold, which can be marked and numbered on the die insert, as shown in Figure 6. During installation, the personnel can install them according to the number by observing the marks and numbers. In addition, in the mold design and development stage, the error proofing of the mold insert installation should be implemented in the mold manufacturing process, so that this problem can be prevented from the early stage and the optimal design can be achieved.
(2) the standardized operation documents shall be prepared for the mold with state switching to prevent wrong and missing installation. The steps and process of mold state switching shall be clearly written, and the inserts which are easy to be installed incorrectly or missed shall be described as the key points of work. After the standardized documents are prepared, the operators will be trained to make each employee clear of the operation content, which is also a way to avoid the wrong installation of die inserts.
Mold parts position offset
Fig. 6 error proofing number on die insert
In the process of mold state switching, frequent disassembly and assembly of mold parts for a long time will aggravate the wear of parts. When the parts are reassembled, the position will shift, which also affects the product quality and die life. In order to ensure the stability of the mold, the positioning pin should be set on the mold insert, as shown in Figure 7. In some larger mold inserts, there are also positioning keys or guiding devices, as shown in Figure 8, to ensure the installation accuracy of the mold insert.
Every time the mold insert is removed, the removed screws and pins should be inspected and stored by category. If there are wear, cracks, sliding teeth and other problems, they should be replaced in time to ensure the accurate and reliable installation and positioning of the mold. At the same time, the removed mold insert should be well protected, and do not bump against the tool edge of the mold. When installing the die insert, first clean the upper and lower surfaces to prevent dust and debris from sticking on the insert, so as to avoid affecting the installation accuracy. Install the insert according to the error proof sign to prevent the wrong position. Then drive in the pin and finally tighten the screw to prevent the screw from loosening and falling off.
Unclear mold status
After the mold is in the window sealing state after production, it is necessary to install the removed inserts from the production line to the mold repair area. Sometimes, if the installation work is not finished in the shift, it will continue to be carried out across shifts. If the work handover is not done well, the mold inserts are not fully installed, and the mold status is not clear, resulting in the mold re production is still in the window sealing state, resulting in the production line shutdown risk. In order to solve this problem, the workshop developed the mold condition tracking software. After each mold disassembly and assembly, when the shift records the mold status on the software, the software will record the latest update time, who is the operator, the operator uses the password to log in, and others cannot change the data. In this way, the other shift personnel first check the mold status in the software, according to the software records, it is very clear that the latest mold status, to prevent the production mold change stop line caused by unclear mold status.
Figure 7 mold insert locating pin
Figure 8 positioning key of die insert
Through the research on the state switching problem of automobile panel die, the causes of the problem were analyzed, and the corresponding measures were taken to avoid the recurrence of the problem, prolong the service life of the die and reduce the maintenance cost of the die. Accumulation of experience in solving the problem of die state switching, to provide help for the follow-up development of automobile panel die, to avoid the problem of mold state switching caused by improper design.