Accessory products of driving recorder are shown in Figure 1. Maximum dimensions of product are 97.80 mm * 37.80 mm * 74.00 mm; average thickness of plastic part is 1.50 mm, material of plastic part is ABS, shrinkage rate is 1.005, and weight of plastic part is 40.60 grams. Technical requirements for plastic parts are that there should be no defects such as peaking, underfilling, flow lines, pores, warping deformation, silver streaks, cold material, and jetting lines, and meet ROSH environmental protection requirements.
Tag: plastic part
There are still many injection molded parts for automobile lights. The more representative ones include headlight masks, headlight decorative frames (transition plates), taillight masks, ellipsoid lenses, light guide strips (plates), etc. Each product has its own processing technology characteristics. Today we will briefly explain headlight mask.
End cover of electric meter is shown in Figure 1. It has a thin-walled structure as a whole, with dense pores on one side to facilitate heat dissipation of device below and serve as a decoration. Appearance size of plastic part is 110 mm * 115 mm * 55 mm, average wall thickness is 2.2 mm, and wall thickness at pores is 3.2 mm. End cap material is PC + 10% glass fiber, with a density of about 1.19 g/cm3 and a shrinkage rate of 0.376%. Material processing parameters are shown in Table 1. This material is a reinforced plastic with a heat deformation temperature of over 120℃. It has high mechanical properties and excellent UV resistance, and is suitable for outer surface of outdoor devices. According to three-dimensional model, volume of plastic part was measured to be approximately 43.4 cm3, and weight was approximately 51.7 g.
See Figure 1 for face shell products of medical therapeutic instruments. Maximum dimensions of product are 198.00 mm * 156.00 mm * 48.00 mm; average thickness of plastic part is 2.00 mm, material of plastic part is ABS, shrinkage rate is 1.005, and weight of plastic part is 172.60 grams. Technical requirements for plastic parts are that there should be no defects such as peaking, underfilled injection molding, flow lines, pores, warping deformation, silver streaks, cold material, and jetting lines, and meet ROSH environmental protection requirements.
Car door panel is an important part of car interior parts. It is located on the inside of car door. It is divided into front, rear, left and right. It varies according to car series, usually two-door and four-door. These parts are collectively called door panel series. This article takes left rear door panel of a car as an example to explain key points and experience in designing injection molds for car door panels.
As saying goes: "No one is perfect, no gold is pure, no one is a sage, no one can make mistakes!" Now, what we want to talk about is that this small ideological mistake has brought immeasurable losses to our work, our company, our department, and even ourselves.
Base is similar to a semi-enclosed box-shaped piece. Coil is installed inside box surrounded by vertical ribs. Outer side where vertical ribs are located and B and C surfaces are exterior surfaces. No push rod marks or obvious parting lines are allowed. End surface where height of vertical rib is located is mating surface with upper shell. Try to avoid setting flat push rods. Side A is installation surface. Bottom surface must be horizontal, a push rod or parting surface can be set. In order to realize two functions of contactor rail installation and screw installation, this plastic part is designed with 2 dovetail grooves and 4*φ5.2mm through holes. In order to be consistent with installation dimensions of other models of contactors, distance and position of 4*φ5.2mm holes cannot be changed, resulting in 2*φ5.2mm holes penetrating dovetail groove that needs to be formed by side core pulling. This is a difficulty in mold design. Material of plastic part is reinforced flame-retardant nylon. Vertical ribs have a large area, a high height, and a thin wall thickness of only 1.2 mm. Allowable draft angle is small, plastic part is easy to stick to mold and trap air during molding. φ14mm hole and fan-shaped side hole are heat dissipation holes, which are located on appearance surface and need to be formed by side core pulling. How to ensure smooth forming and demoulding of vertical ribs and side holes, while ensuring that there are no push rod marks or obvious parting lines on appearance, is also a difficult point in mold design. 3.0, 9.3, and 12.8mm slots are clamp installation slots and require side core-pulling molding.
Structure of plastic part is shown in Figure 1. It is 43mm high and has 4 nozzles. One of nozzles has threads on inner surface (M28mm, length 11mm). Outer diameter of nozzle where internal thread is located is φ34mm. Material of plastic part is ABS, which is relatively hard, so internal thread cannot be forcedly demoulded and needs to be demoulded by rotating thread core. Four ribs are provided on outer cylindrical surface of plastic part. Four ribs are formed in cavity to prevent plastic part from rotating together with internal thread core.
Gutter is drainage system of car. Its mesh structure has function of guiding rainwater and blocking debris. The overall dimensions of this plastic part are 1430mm * 429mm * 125mm. It is a two-color plastic part, as shown in Figure 1. Main material Use PP+TD22, and mesh material uses PP+EP-DM+TD22. Compared with main material, material added to mesh, EPDM ethylene propylene diene rubber, is a copolymer of ethylene, propylene and a small amount of non-conjugated diene. Main chain is composed of chemically stable saturated hydrocarbons, so it has excellent ozone resistance, heat resistance, weather resistance, aging resistance and other properties, is widely used in automotive seals and other fields. If this sink gutter is formed using a traditional flat rotating two-color mold, mold volume will reach 2150mm*2200mm*1074mm, and a 3.3×104kN rotating two-color injection molding machine will be used. However, customer company's ordinary injection molding machine with a maximum capacity of 1.3*104kN was transformed into a double-barrel injection molding machine with a rotating mold plate in the middle. In order to adapt to customer's machine production, a three-dimensional rotating laminated two-color injection mold structure scheme was selected, which consists of 2 pairs of molds. Volume of a single pair of molds is 1230mm*2200mm*1074mm. The two molds are stacked vertically on injection molding machine, and intermediate code mold plate can be rotated 180° to exchange cavity, as shown in Figure 2. Difficulty of mold design in this scheme is low. One mold injects main body of plastic part, and the other mold injects mesh of plastic part. Fixed mold cavities of two molds are different, and movable mold is exactly same. Cavity conversion is realized by rotating movable mold through intermediate code mold plate of injection molding machine. Mold structure is designed to be compact to control mold size within applicable range of selected injection molding machine.
Printer drain product is shown in Figure 1. Maximum dimensions of product are 226.59 mm * 44.58 mm * 67.80 mm; average thickness of plastic part is 1.00 mm, material of plastic part is ABS, shrinkage rate is 1.005, and weight of plastic part is 23.53 grams. Technical requirements for plastic parts are that there should be no defects such as peaking, underfilled injection molding, flow lines, pores, warping deformation, silver streaks, cold material, and jetting lines, and meet ROSH environmental protection requirements.
Gud Mould 