2.2 Mold Design and Manufacturing
When producing a plastic part, the molds must be designed and manufactured using various machines. In this study, the steps applied for manufacturing the plastic product of the DVD-ROM cover are described and shown in Fig. 1. In the plastic injection molding, the CAD model of the plastic product of the DVD-ROM cover was designed in the Pro/Engineer Wildfire CAD/CAM program. Also, the mold designed for the DVD-ROM cover consisted of two clamping plates, a core plates, and pins.
In fabricating the mold components, some machines such as CNC milling, EDM machining, drilling, and grinding were employed. The material utilized for the mold components was selected as DIN 1.2738 (IMPAX) steel. This material’s hardness was measured to be 31 HRC with a Wolpert Instron Instrument and its chemical composition is presented in Table 3.
2.3 Finite Element (FE) Analysis and Molding Cycle
2.3.1 FE Pre-Processing of the DVD-ROM Cover. The 3D model of the DVD-ROM cover part was imported into the Moldflow Plastic Insight 5.0 (MPI 5.0) (Ref 18). The DVD-ROM
Fig. 1 The steps applied for producing the plastic product of the DVD-ROM cover
Table 3 DIN 1.2738 (IMPAX) material’s chemical composition (%)
Table 4 The material properties of ABS polymer
Commercial product name LG Chemical (HI-121)
Melt density, g/cm3 0.91459
Solid density, g/cm3 1.0175
Material structure Amorphous
Moldflow viscosity index VI (240) 142
Thermal conductivity, W/m °C 0.1960
Specific heat, J/kg °C 2449
Modulus of elasticity, MPa 2240
Shear modulus, MPa 805
Poisson ratio 0.392
cover part has dimensions of 153, 45.17, and 7 mm. The polymer material (ABS) for the DVD-ROM cover part was composed of CMOLD generic estimates, and its material properties are listed in Table 4. The ABS polymer material was also dried for 4 h using a drier before the molding cycle. The FE model of the DVD-ROM part was created by discretizing the geometry into the smaller simple elements. The FE fusion mesh model, as shown in Fig. 2, consisted of 2726 nodes, 69 beam elements, and 5318 triangular elements.
2.3.2 Molding Cycle of the DVD-ROM Cover. The mold components were designed and manufactured to inject the plastic material of the DVD-ROM cover part, which is mounted
Fig. 2 The FE mesh model of the DVD-ROM cover product
on the front of a computer body to fix a DVD within a DVD-ROM. The plastic injection machine which is used in this study was a NETSTAL (600 H-110 60 tons 1.66 oz (25 mm)) made in Switzerland. This plastic injection machine has the technical specifications of a maximum clamp force of 543 tons,
a maximum injection pressure of 243 MPa, a maximum injection rate of 491 cm3/s, a screw diameter of 25 mm, and machine hydraulic response of 0.2 s.
3. Statistical Methodology
yi ¼ b0 þ b1xi1 þ b2xi2 þ ··· þ bk xik þ ei ðEq 8Þ
The least square method selects the b coefficients for minimizing the sum of the squared of the errors, ei. The final least square function can be written as follows: 塑料注射成型收缩值英文文献和中文翻译(5):http://www.751com.cn/fanyi/lunwen_79121.html