Skills are techniques that accumulate experience in production and then refine it. The skill of assembly comes from production,
It is the accumulation and summary of experience, so one must have a certain amount of experience, and it is impossible to have good skills without knowledge of assembly principles.
The assembly principle is simply to make the electrodes of the LCD screen correspond one-to-one with the corresponding control electrodes on the circuit board. Therefore, based on experience
On the basis of principles, fully utilize assembly skills to promote production. Assembly techniques are extremely useful in overcoming the alignment difficulties caused by raw materials. Due to the unqualified raw materials such as shells, screens, and circuit boards, their alignment methods have become ineffective, making it impossible to assemble according to the original procedures and process documents. In other words, the assembly at this time is blind. For the alignment difficulties caused by these reasons, two main techniques are adopted to solve them. One is to search for the alignment benchmark again; The second is visual alignment. Additionally, there is the use of tooling for alignment.
Sometimes, due to raw material reasons or accumulated tolerances, the alignment reference between the screen and the shell or between the shell and the plate specified in the original process documents fails, and it is necessary to search for a new alignment reference in production to achieve assembly positioning. Before searching for the alignment benchmark again, it is necessary to analyze the reasons for the failure of the alignment benchmark and find solutions in order to achieve targeted and smooth production. The main reasons for the failure of the alignment benchmark are the three basic assembly materials of the shell, screen, and circuit board.
The most common type of alignment benchmark failure is caused by the shell, which is mainly manifested by the excessive positive tolerance of the long side of the shell, exceeding the width of one electrode, resulting in edge alignment failure. The pinhole position is incorrect and cannot be aligned. The wide edge is too long, which creates a certain angle on the screen and causes electrode misalignment. The long side of the shell is too long, resulting in an increase in positive tolerance. Since the electrode width of the screen and board is constant, if edge alignment is used, it will cause excessive displacement of the screen electrode beyond the design. When the displacement exceeds one electrode, assembling according to edge alignment will inevitably result in misalignment of the screen and board electrodes, leading to assembly failure. At this point, it is necessary to reconfirm its alignment benchmark. There are two benchmarks for assembly alignment, one is the alignment between the screen and the shell; Another is the alignment between the shell and the circuit board. Due to the fact that the alignment reference between the shell and the circuit board is often based on the shell foot for edge alignment, edge alignment can still be used to ensure that one side of the screen is tightly attached to the shell; But when changing the alignment benchmark between the shell and the circuit board, the selection of shell legs should be determined based on experiments.
If the difficulty in alignment is caused by inaccurate pinholes in the shell, due to the failure of the alignment reference between the screen and the shell, the alignment reference between the shell and the circuit board needs to be changed accordingly for the same edge alignment. Instead of aligning the pinholes between the circuit board and the shell on the same axis, the circuit board should be moved in the same direction relative to the shell with a positive tolerance to compensate for the electrode gap caused by the tolerance and achieve alignment.
Overall, finding a new alignment benchmark requires practical experience and actual assembly. Sometimes, the tolerance is too large and the electrode spacing is small, making it extremely difficult to find an alignment benchmark. Some experienced people make full use of assembly principles to overcome errors and perform assembly, which is visual alignment.
