Plastic parts of heavy vehicles abroad

From the sheet molding compound (SMC) parts production

Sheet Molding Compound (SMC) is a manufacturer of dry glass fiber reinforced unsaturated polyester molding products. 20th century, early 60s, the plastic for the first time in Europe appeared after the United States and Japan have developed the processing technology of the plastic material. About the late 60s in the 20th century, the global demand for SMC had begun to take shape, then 20% annual growth rate of 25%. SMC's main advantages are:

● Compared with the metal, its electrical performance is superior, with corrosion resistant properties of the medium, and the price is lower, engineering design flexibility.

● Compared with reinforced thermoplastics, the material has a product is not easy deformation, mechanical properties and high heat distortion temperature resistance, chemical corrosion.

● hand lay and spray with glass compared to the material in the molding cycle, working environment, product appearance and other aspects of performance is a plus.

At present, SMC is widely used in transport vehicles, construction, electronics, appliances and other industries. In order to promote SMC and other composite materials in automotive applications, the foreign establishment of the "Alliance of Automotive Composite Materials (ACA)". The Alliance has 25, including mold, tool manufacturing and raw materials, including suppliers, they are able to offer composite products for the automotive industry. Table 1 is the development of the Union in 2000, the use in heavy vehicles on the SMC components. Currently, VOLVOF12 cab left and right side wind guide mask and hood are made of SMC as its material.

Plastic expansion tank

Expansion tank is a demanding functional parts, it is necessary to meet the temperature requirements of the engine cooling system, but also withstand the test of the external climate, it requirement in -40 ℃ ~ 120 ℃ between the performance and stability, should also bear the cabinets overpressure of 100kPa, the test voltage of 4kPa.

VOLVO heavy trucks in Sweden, Germany and Japan, Hino bus MAN trucks are equipped with plastic expansion tank. Which, VOLVO As a result of the expansion tank translucent polypropylene (PP) manufacturing, making the green antifreeze level at a glance. The cabinet is made by the upper and lower flange of the injection molded parts welded together, there are some divisions within the cabinet, thereby increasing the overall strength of the cabinet to improve their applications. The plastic expansion tank is installed in the cab on the lower bracket, with screws.

MAN expansion tank with black plastic manufacturing, material is 20% glass fiber reinforced PP (VESTOLENP9503). Blow molding of the tank through the middle of the expansion tank used to strengthen tendons divided into eight water chamber, so that the improved strength of the tank, but also allows for heat dissipation. The average wall thickness of the water tank 3 ~ 4mm, the minimum wall thickness of 2.5mm. To save space, the expansion tank is made of flat, its length, width and thickness are 94cm, 38cm, 8cm.

Hino expansion tank also use black plastic, which consists of two injection molded parts with a flange welded. Tank liquid level sight glass for the upper and lower, respectively, are allowed at the highest level and lowest level. Observation hole is to use it with transparent plastic box welded together, with red floating bead hole, the use of the ball float and fall to determine the liquid level. The installation of the tank is then bound by metal bands first be installed in the cab on the rear of the bracket.

And VOLVO, MAN and Hino compared to the expansion tank, expansion tank made the main problems are: products, rough, uneven surface, there are irregular thin. Of the problem is mainly due to the rough surface of the mold; the interface, welding parts are misplaced, unfair phenomenon, there is sealing off problems, the main reason is improper welding; material texture and transparency and also significantly less compared to foreign parts; wall thickness uniformity, plus liquid outlet and cover the machining accuracy to be further improved.

Usually, the use of blow molding technology, the expansion tank usually requires welding accessories. Information can be found in the weld strength requirements, such as: When welding in the Annex vertical plane force 980N applied should not cracking; when the direction of the welding surface 9.8N • m of torque applied should not be generated when the cracking.