Design of Core⁃Pulling Mechanism of Variable Cross⁃Section Bend of Sprinkler Based on Mathematical Model of Demolding Force

doi:10.19491/j.issn.1001-9278.2020.10.011

Abstract

Abstract:

According to the characteristics of the inner wall of curved pipe with variable cross-section and the inner wall of straight pipe， the mathematical model was established for the demolding force of the inner wall of curved pipe by using a calculus method， and the demolding force of the core of connecting pipe was calculated. Based on the obtained results， the demolding mechanism of the inner wall of curved pipe was optimized and designed for the plastic part， and this mechanism was driven by a single oil cylinder to rotate and pull out the core of the two-sector gear bent pipes. On the basis of the demolding mechanism set in this work， the mold structure of plastic part was composed of a mold with two cavities and a single opening and two-plate mold. In this mold， there are two groups of external thread demolding mechanisms with a Haver slider and a sector gear bent pin core-pulling mechanism driven by a linkage oil cylinder. The die structure is simple and practical， and the action of mechanism is reliable. This design can offer a good reference for design of other similar molds.

Key words: wariable section elbow, mechanism design, core pulling of elbow, injection mold, calculation of demolding force, mathematical model

CLC Number:

TQ 320.66⁺2

PENG Guorong, SUI Lili, LU Longfu. Design of Core⁃Pulling Mechanism of Variable Cross⁃Section Bend of Sprinkler Based on Mathematical Model of Demolding Force[J]. China Plastics, 2020, 34(10): 63-68.

Figures/Tables 7

Fig.1. Shower shell plastic part

Fig.2. Setting of parting and forming parts

Fig.3. Analysis of the enveloping force of the straight cylinder core

Fig.4. Stress analysis of bend core

Fig.5. Calculation of tight force of bend core

Fig.6. Design of demoulding mechanism

Fig.7. Mould structure

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