Coffee pot handle gas-assisted injection mold design

 

Abstract: The coffee pot hand tenon, because there is a very big difference in the thickness and shape of the structure is a complex process using ordinary dregs hard plastic molding, gas-assisted injection molding must process. Based on the structural characteristics of the product, the use of gas-assisted injection molding j two arts and design their own mold, in the actual production applications, and achieved good results.

 

Keywords: coffee pot hand tenon; gas-assisted injection molding; mold structure

 

CLC: TC76 Document code: A Article ID :1009 -9492 (2005) 03-0042-02

 

1 Introduction

 

    Compared with conventional injection molding, gas-assisted injection molding process increases a gas N,) injection phase. Its advantages are manifold: ① can produce t hollow "plastic products, weight, save material; ② increase human freedom in product design, wall thickness unrestricted; ③ products rigidity, surface quality; (D shorten the production cycle, improve die life, etc. "11, but due to the introduction of new gas-assisted molding process process parameters, such as: the amount of initial melt injection, gas injection time and the gas pressure, making the mold design and practical application of the more traditional injection forming complex, we must consider the location of the gas injection point and the intake structure of the mold | 21.

 

Two plastic parts process analysis

 

    Coffee pot handle shown in Figure 1, the handle is made of modified PP, handle streamlined, thinner than people, the whole plastic parts uneven thickness, ordinary injection molding process is difficult, you must use gas-assisted injection molding a molding. For the plastic parts of the structure and appearance of the playing characteristics of demand, the use of the United States around MOLDFLOW MPI software module dedicated gas-assisted molding Gas-Assisted injection molding) simulation analysis, taking into account the overall structure of the mold, and finally determine the use of two latent water poured LJ ¨ Figure 1A, B two) and two gas injection point in Figure 1C, D two) of the mold structure is more reasonable | 31.

 

3 Principles and structure of the mold cooling

 

    Ⅱ) Structural analysis did not count

 

    From the analysis of plastic parts process has identified coffee pot handle molding process is the use of gas-assisted injection molding. Considering coffee pot neck as a ring, neck near the top of the inside of the handle assembly with a profiled bore, forming the core must be used within the pumping structure; same time as the overall shape of the ends, but the middle is small, the cavity must be lobe clamping structure.

 

    Figure 2 shows the structure of the mold: mold on both sides of the ramp flap slider 6 7 dovetail rail to guide through and under the action of the spring 18 oblique parting; inserts from the fixed mold 10 and the movable mold insert 30 docking constitute a complete mold core; nitrogen cylinder block 32 mounted on the movable mold base plate, two active intake manifold 37 through the movable mold insert 30; gas injection, the gas inlet pipe 37 by the active gas needle through the slider 23 26 into the interior plastic parts to achieve gas-assisted injection molding process, in order to prevent I}: In the mold opening into the trachea with the movement of the slider 23 to interfere, intake manifold using the activity structure, mold forward trachea start to exit slide 23 ; internal oblique and curved by the pulling mechanism 22 and the slide pin 23 formed of pieces 15, 16 formed Sha by positioning the slider 23 is set, security for oblique and curved pin 22 into the mold when the slider 23 can be accurately inclined holes the slider is reset; since two latent poured L ", sprue and runner in the cold material using Z-pull rod 33 so prolapse, sliders 23 and pulling rod 33 will cause interference, you must slide 23 , I asked to open an avoidance 7L.

 

Q) works

 

    Mold works as follows: when the mold, the slider 6 and the slider 23 is inclined in the clamping force of the accurate reduction, active inlet pipe 37 in a nitrogen gas cylinder 32 drives the slider 23 F inlet into and through the sealing ring 38 for sealing; when the plastic injection adjusted by a certain amount), the entry delay time f scraping; delay time f scraping after a certain pressure nitrogen gas spring 24 overcomes the action, open the gas needle valve 25 into the plastic Internal parts, realized gas injection molding; mold prior activity in a nitrogen inlet pipe 37 is driven by the air cylinder 32 to start block 23 qJ exit from the mold parting surface open, inclined slider 6 under the action of the spring 18 along the dovetail generate oblique parting rails 7, through artificial remove products, the push plate 35 and the push plate plate 36 in the injection machine ejector structure under the effect of pulling rod 33 through the gating system.

 

B) mold cooling

 

From the structure of the mold can be seen that, by the products of the human part of the surface shape inclined slider, and the fixed mold insert block 10 and the movable mold insert block 30 is also in contact with the oblique slide, mold cooling mainly for the oblique slide sufficient, without the need for cooling the mold core. Each diagonal pass into the slider are two U-shaped cooling water, the effect is very satisfactory.

 

4 Conclusion

 

    Figure 2 shows the coffee pot handle gas-assisted injection molding tool has been used in actual production, processing of the products shown in Figure 3, the product surface quality, the appearance of integrity, no welding marks, while the intake manifold through the activities to resolve the Note gas system and the structure of the inner core pulling interference problems. Practice has proved that this production is feasible.