Automotive Design. Car rearview mirror design(1)
The car rearview mirror is an important part of the car exterior parts. It is located on both sides of the car and is one of the most important exterior parts of the car. The car rearview mirror is a device used to allow the driver to observe the condition of the road during driving. It can be said to be the driver's eyes. The car rearview mirror is generally composed of a mirror ring, a base, a mirror case, a bracket, a rotating shaft and the like.
1 Plastic parts appearance requirements and structural analysis
The picture above shows the parts of the Ford Mondeo rear-view mirror housing. The material is ABS. The shrinkage is generally 1.005. The plastic parts are left and right mirrors. The number of mold cavities is 1+1. Plastic parts are appearance parts and are one of the most important exterior parts of automobiles. The dimensions of the plastic parts are: 254.2*122.5*120.6mm. The characteristics of the plastic parts are as follows: (1) The plastic parts are external parts, the appearance of the plastic parts is high with fine-grained parts, and the low parts are painted parts, and the appearance requirements are extremely high. (2) The shape of the plastic parts is complex, the appearance of the clamping line is extremely high, the outer side of the plastic part has a large area of inverted buckle, the inner side has 6 inverted buckles, the inverted buckle is large and the area is large, which is typical of the automobile rear view mirror mold. structure.
2 mold structure analysis .Automotive Design.
According to the structural characteristics of the mirror shell plastic parts, the mold preferentially adopts the hot runner injection molding structure, adopting 1 point open type + cold flow channel + banana type gate (commonly known as horn). There are 7 inverted buckles on the inner and outer sides of the plastic parts. The mold has a large area of reverse buckle and many reverse buckles. The four inner buckles on the inner side of the mold adopt the structure of the oblique push block core pulling, the inverted buckle 5, and the inverted buckle 6 adopts the structure of the oblique push block + the straight push block combination for the reverse buckle block area, for the mirror shell mold After the plastic part is released from the mold, it can only be taken by hand. The premise is that there must be space for manual picking when picking up the piece. Since the outer side of the plastic part is inclined due to the direction of the die, the inclined slider core structure is adopted. The die has dimensions of 800*600*647(mm) and a total weight of about 0.9 tons. It is a medium-sized injection mold.
2.1 Molded part design
The mold fixed mold is inlaid and spelled, the commonly used material is: 2344. The fixed mold is the same material. When ordering the material, it should be noted that the hardness of the moving mold is about 2 degrees smaller than the fixed mold, so as to avoid the same hardness, because the constant hardness of the fixed mold makes the mold easy to wear and insert. The principle of molded part design is to minimize the size and life of the mold to reduce the manufacturing cost and production cost of the mold. The rear view mirror mold life of this model is 300,000 times, so the material is 2344.
2.2 Pouring system design
The mold pouring system adopts hot runner feeding, adopts a 1-point open hot runner + cold runner + banana gate, and the plastic material is ABS.
Since the plastic part is ABS material, the material has good fluidity. The design of the flow channel is wider when designing the flow channel, but the length of the flow path from the hot mouth to the edge of the plastic part is designed to be within 60mm. If it is not, try to control it at 100mm. Within, avoid cold runners too long and avoid pressure loss. Automotive rearview mirror housing injection mold hot runner gate location. Automotive Design.