Injection mould for left and right armrest inserts
The left and right armrests are important parts of a treatment chair. The product diagram is shown in Figure 1. The maximum size of the product is 201.34 mm x 81.78 mm x 60.61 mm, the average thickness of the plastic part is 12.00 mm, the material of the plastic part is PA6+50% GF, the shrinkage rate is 1.004, and the quality of the plastic part is 124.20 gram. The technical requirements for plastic parts are that there must be no defects such as peaks, dissatisfaction with injection molding, flow lines, pores, warpage deformation, silver streaks, cold materials, jet lines, etc.
It can be seen from Figure 1 that the structure of the plastic part is L-shaped, one end of the cylinder has an inner hole, which needs to be inserted into the hardware, and its circumference has a uniform tooth shape, which can play a stable role after being embedded in the plastic.
The purpose of inserts in plastic parts is to increase the local strength, hardness, wear resistance, conductivity or magnetic permeability of the plastic parts; or to increase the stability of the shape and size of the plastic parts, reduce deformation, and improve accuracy; Or to reduce plastic
The trumpet and meet many other requirements. The materials of the inserts include various non-ferrous or ferrous metals, as well as glass, wood, and molded plastic parts, among which metal inserts are most commonly used.
The use of inserts generally increases the cost of the plastic parts and complicates the mold structure. In addition, the installation of the inserts in the mold during the molding of the plastic parts will reduce the productivity of the plastic parts, and it is difficult to realize automation. Use the already formed plastic part as a mold for inserts,
We generally call it an insert mold. The overmolding mold can achieve the same effect as the two-color mold, and it is also a good choice when the two-color molding machine is lacking.
After the metal insert is inserted into the plastic, there will be various problems, the common precautions are as follows;
1) After the metal insert is inserted into the plastic, in order to ensure that it is firm and reliable, does not loosen, and does not slip off, it is necessary to make steps, undercuts, patterns or knurling in the embedded part of the metal insert to prevent it from falling off.
2) The shape and size design of the metal inserts need to pay attention to the craftsmanship, the inserts are easy to process, can be reliably positioned during injection molding, and can be easily ejected and demolded after injection.
3) Due to the different properties of the two materials, especially the different coefficients of thermal expansion, the metal insert may cause the plastic parts around the insert to crack. If a copper nut is inserted into the PC material during injection molding, it is prone to cracking. Need to be The preheating of the insert can avoid cracking.
4) It is not suitable to design a multi-cavity mold with a mold for placing the insert, because it takes time to place the insert and delays the injection cycle. Therefore, a comprehensive evaluation is required during mold design.
The material of the plastic part is PA6+50%GF, and the shrinkage rate is 1.004. Nylon and glass fiber can play a reinforcing role. After glass fiber is added to plastic, the shrinkage rate is significantly reduced, and the decline is getting bigger and bigger with the increase of glass fiber content. In the design When using a mold with a high proportion of glass fiber plastics, it is necessary to pay attention to the small shrinkage rate of large or complex products, while the shrinkage rate is anisotropic.
The plastic part is symmetrical, the mold design cavity ranks 1+1, and the mold base is the CI3540 standard mold base. The gate is designed for submersible thimble to feed glue. The side of the elbow of the plastic part with the insert is designed on the ground side of the mold, and the slider core needs to be designed. The sky side of the mold embryo
The fixed mold and movable mold blanks also have positioning pins to increase rigidity.
In order to facilitate the fixing of the inserts, the slider is driven by an oil cylinder. The bottom of the slider is designed with a wear-resistant plate 17, made of 9CrWMn, heat-treated HRC60-62, and an oil groove is opened on the surface. When the oil cylinder is core-pulled, it is necessary to design the inclined wedge 19 in order to lock the oil cylinder. Dynamic model
For core-pulling molds, the cylinder can be easily locked with a wedge. In fixed mold core pulling or some hot runner molds, sometimes it is difficult to lock the oil cylinder, and it is necessary to design the oil cylinder to lock the oil cylinder or other mechanisms to lock it. The slider needs to be reset before closing the mold, Easy to put in the insert. A guide post is designed at the bottom of the cylinder mounting plate to provide guidance for the movement of the cylinder piston rod and increase rigidity. When designing the mold of the cylinder core pulling, it is necessary to pay attention to the design of a connecting block on the head of the cylinder piston rod. One side of the connecting block is made with a screw hole, and the thread of the cylinder piston rod is screwed into this screw hole. The other end of the connecting block is designed with a T-shaped block. The T-slot should be designed to connect with the connecting block. Do not screw the thread of the piston rod directly into the slider, so as not to cause the slider to move unsmoothly.
ABIS MOLD TECHNOLOGY CO.,LTD
Daisy Wang (Sales Engineering)
M: +86-150 1652 6799
E: daisy@abismold.com
A: Building B#,YingKeli Industrial Part, LongDong Community, LongGang District, Shenzhen, China 518116
WhatsApp: +86 136 8261 9739
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