第1个回答 2011-02-26
Abstract: This paper analyzes thin tube slender tube-type plastic pieces of the structural characteristics of the process. And in accordance with the characteristics described in detail tube plastic parts injection mold structure and its working process, to determine a reasonable way of injection and mold release.
Key words: Process; gating system; ribbed tube; Injection Mold
1 Introduction
In the mold design process, often encountered in long thin tube-type injection parts, such parts of the larger aspect ratio, and shape permit must have the taper. Injection molding of such parts, there are often non-uniform tube wall thickness, surface with flow defects such as marks and charred. Therefore in the design of injection molds need to consider the casting mold system, exhaust system, cooling system, the introduction of the system. At the same time should also be considered loaded mold mold mold height and open itinerary. Mold structure as far as possible, compact, open-mode trip short.
2, process analysis
Shown in Figure 1 for the plastic tube size chart. Materials for the PS (polystyrene). We can see from the parts belong to the shape of thin elongated tube-type injection parts, die design and die in the process to determine the structure needed to be considered. Fig know by the size, wall thickness 1.5mm, the outer diameter size! 24mm, length 150mm, there is at the bottom of tube M24 × 30mm outer thread of the ordinary. Product requirements of uniform wall thickness, internal and external cavity surface smooth, burr-free edge fly.
Because of long thin tube-type injection parts, such parts of the larger aspect ratio, it focuses on mold design and injection molding Demoulding selection on the way. Because of thin-walled tube, and筒身longer, it had not yet reached the molten plastic in the entire cavity is likely to occur before condensation and should not make a complete injection molding parts. In addition such slender parts by injection mold machine and therefore can not be away from the conventional way of Demoulding Demoulding.
Injection molding machine according to the selection of production conditions in the SCZ-125-type injection machine. Their specific parameters are: a high degree of loading mode: 150 ~ 300mm. Open-mode distance: 300mm. The level of column spacing: 400mm. Vertical column spacing: 400mm. A maximum injection capacity: 125g.
3, mold design
Three die structure using one mold plate structure 4.
Plastic parts to determine the shrinkage rate of 1.3%. Demoulding gradient plastic parts in accordance with the molding process characteristics and the characteristics of plastic parts selection Demoulding cavity gradient 0.6 °, angle core Demoulding identified as 0.5 °, Figure 2 shows Demoulding add gradient plastic parts after various parts of the material thick-size map.
Because of plastic parts at the bottom there is the outer M24 × 30mm thread, it must die structure using fractal lateral agencies. Injection Mold through the spring and the role of lock block to complete block of lateral Hough fractal core-pulling action.
Injection Mold Design Demoulding manner shown in figure 3. Push the board to adopt the way the introduction of plastic parts. And to reduce the top of the distance from the injection molding machine using a direct role in the top bar at the push plate. Greatly reduces the loading height mode.