The design of the product structure is also very important. This is entirely a matter of experience. There is no shortcut. In this regard, each series has its own characteristics. Etc., shrinkage deformation caused by uneven wall thickness, etc., there are mainly the following types of screw prevention: three rib prevention, hoop prevention, neck prevention, stamping prevention, neck prevention due to the influence of technical process It is not used much, and most of them use the neck mouth to prevent it from falling. The realization of the above structure is based on the precondition that the plastic material is PA66. Here, it is necessary to explain the neck mouth prevention. Taking the screw as M3 as an example, the actual screw of M3 The outer diameter is φ2.90mm, so the size of the shell neck should be designed in: φ2.5～φ2.6, the thickness of the shell neck should be 0.4～0.5mm, and there should be a section under the screw head smaller than the shell neck. In order to ensure that the screw can be screwed into the thread smoothly, the production process should also be adjusted accordingly. The following is a statistical and solution plan for the structural problems of each series of products.
1. The main reason for the deformation of the long-digit number of spliced product combinations is that the unreasonable structure causes the two spliced falcons to be unbalanced in the front, back, up, down, left and right forces. It is shown that the force and deformation of the spliced falcons should be considered in the structural design. direction.
2. The problem of preventing the screw from falling off. In this regard, I recommend using the neck mouth to prevent it as much as possible, because it avoids the troubles caused by the tolerance accuracy of the screw rod and the hoop mouth compared with the hoop mouth prevention. And the structure is reliable and the tolerance is easy to control.
3. The problem of salt spray test of screws and threaded steel parts after electroplating is based on the company's thread electroplating standard in 2012 (the coating is limited, but I think the thickness of the thread corresponding to the coating needs to be further determined) to solve this problem. When the electroplating process is normal, there are two methods, selecting the correct sealing agent and using the plating layer to electroplate multiple times. Both methods are to cover the pores generated by the screw that are invisible to the naked eye. The cost of electroplating in multiple times is high, so it is recommended to use the first method, and the key to this method is the research on the formula of the sealing agent.
