CN106363884A

CN106363884A - Injection molding method for commercial vehicle sun shade

Info

Publication number: CN106363884A
Application number: CN201610798710.2A
Authority: CN
Inventors: 梁磊; 刘超; 李秀玲
Original assignee: JIANGSU XINQUAN AUTOMOBILE ACCESSORIES CO Ltd
Current assignee: JIANGSU XINQUAN AUTOMOBILE ACCESSORIES CO Ltd
Priority date: 2016-08-31
Filing date: 2016-08-31
Publication date: 2017-02-01

Abstract

The invention relates to a manufacturing process of vehicle decoration pieces, in particular to a molding process for a commercial vehicle sun shade product. The process aims at solving the problem that the shearing rate in a traditional injection mold gating system is too high, and the product quality can be effectively improved through an injection molding method for a commercial vehicle sun shade. The injection molding method for the commercial vehicle sun shade particularly comprises the following steps that (1) melted plastic passes through a middle position hot runner main spraying nozzle, passes through two-point hot runners and then passes through a middle-position cold runner sprue to enter a product cavity; (2) a second cold runner sprue, a third cold runner sprue, a fourth cold runner sprue and a fifth cold runner sprue which are symmetrically arranged on the two sides of the middle-position cold runner sprue are opened in sequence, and the melted plastic is injected into the product cavity; and (3) the injection pressure at all sprues is kept until the product cavity is filled with the melted plastic.

Description

A kind of injection molding forming method of commercial car sky shade

Technical field

The present invention relates to a kind of manufacturing process of automobile decoration piece, in particular to commercial car sky shade product forming technique.

Background technology

With growth in the living standard, the requirement also more and more higher to driving safety and comfort level for the people, in commercial car side Face, has a higher visual field, roomy front windshield, brings stronger light, at the angle just to the sun or night simultaneously Accent light, the potential safety hazards such as visual dizziness can be produced, so in the design of passenger car, design above front windshield One width exceedes the sky shade product of windshield, and product belongs to the exterior trim of automobile, and Weatherproof ageing-resistant performance requirement is higher, and And require impact strength >=16kj/m², tensile strength >=40mpa, product is commonly defined as translucent, light transmittance≤24%, with This come to ensure in-car light intensity.

Generally using the moulding process of injection, traditional is injection molded with three below defect to sky shade product: 1. adopt , entering glue, briquetting pressure is big for the generous material of whole one, and injection speed is slow, low production efficiency；2. when entering glue, shear rate is high, Shearing leads to material to decompose, and produces the filamentary silver of product appearance, produces unstable, conforming product rate is low；3. enter the material handle of glue position Weight, product material wastes seriously, and the pruning needs polishing of material handle produces dust etc. and pollutes, and production needs manually to become in a large number This.

Sky shade product length, width and height size is about 2363*360*430mm, product wall thickness 5mm, and product weight about 6kg is Ensure that product appearance does not have weld bond, the running gate system of product enters glue using sequence valve, maximum the cutting of hot flow path order valve system Cut generation and enter glue point position in first hot flow path, it is too high to enter glue process medium shear rate, produce substantial amounts of shear heat and lead to product The decomposition of material, the appearance of product is the defect of filamentary silver or referred to as high temperature silk.

Content of the invention

Present invention aim to address the too high problem of shear rate in traditional System of Injection Moulding, provide one kind The injection molding forming method of the commercial car sky shade of product quality can be effectively improved.

The technical scheme realizing the object of the invention is as follows: a kind of injection molding forming method of commercial car sky shade, specifically includes Following steps:

1) plastics of melting are passed through interposition hot runner main nozzle, through 2 points of hot flow paths again through interposition cold runner Cast gate, enters product die cavity；

2) the symmetrically arranged second cold runner cast gate in interposition cold runner cast gate both sides, the 3rd cold flow are then opened in order Road cast gate, the 4th cold runner cast gate, the 5th cold runner cast gate, incorporate plastics to the injection of product die cavity；

3) keep each cast gate injection pressure, until product mold filling is full.

Above-mentioned steps 1) in the internal needles of 2 points of hot flow paths and melt chamber through increasing polishing.

The pressure time curve parabolically shape of each cold runner cast gate above-mentioned, pressure peak scope is 60～70mpa Between, pressing time is maintained between 30～35s.

Injection moulding process of the present invention passes through moldflow software analysis shear rate, enters glue using 2 points of hot flow paths, compares list Click through gluing method, former shear rate is 46917 [1/s], and the shear rate of the running gate system of optimization is 26009 [1/s], shearing speed Rate decrease beyond 40%, being greatly reduced it can be avoided that product material produces decomposition the defects such as filamentary silver of shear rate, thus It is effectively guaranteed the appearance of product, and avoid the fall producing mechanical property in the ageing process in the future using Low, the defects such as product cracking occur；This method by the design of 2 points of hot flow paths interposition cold runner cast gate material on it is ensured that two The melten gel of point hot flow path merges at interposition cold runner cast gate, and the needle within 2 points of hot flow paths and melt chamber are passed through and increased, Polishing, reduces shear rate.

Brief description

Fig. 1 is this method mould schematic diagram.

Fig. 2 is this method injection pressure time plot.

Specific embodiment

See Fig. 1 and Fig. 2, a kind of injection molding forming method of commercial car sky shade, specifically include following steps:

1) plastics of melting are passed through interposition hot runner main nozzle 1, through 2 points of hot flow paths 2 again through interposition cold flow Road cast gate 3, enters product die cavity 8；

2) then open the symmetrically arranged second cold runner cast gate the 4, the 3rd in interposition cold runner cast gate both sides in order cold Runner cast gate 5, the 4th cold runner cast gate 6, the 5th cold runner cast gate 7, incorporate plastics to the injection of product die cavity；

3) keep each cast gate injection pressure, until product mold filling is full.

Above-mentioned steps 1) in the internal needles of 2 points of hot flow paths 2 and melt chamber through increasing polishing.

By the running gate system of optimization it is ensured that first shear rate entering glue point is minimum, remaining enters glue point order and enters Glue avoids weld bond, and in the pressure maintaining period of product, can effectively ensure that the large scale demand of product.

Whole set of die passes through the Design of Runner System of innovation, and during molding, filling balances product, the shearing of product Speed is less, and the internal stress of product is little, and deflection is little, produces stable, efficient, the light transmittance of product is guaranteed.

The above invention embodiment, simply list the parameters optimization of part, not detailed illustrate all of can be excellent Change scope, but, it should think on the premise of without departing from theory of the present invention, similar modification and optimization deformation broadly fall into this The protection domain of invention.

Claims

1. a kind of injection molding forming method of commercial car sky shade it is characterised in that: specifically include following steps:

1) plastics of melting are passed through interposition hot runner main nozzle (1), through 2 points of hot flow paths (2) again through interposition cold flow Road cast gate (3), enters product die cavity (8)；

2) the symmetrically arranged second cold runner cast gate (4) in interposition cold runner cast gate both sides, the 3rd cold flow are then opened in order Road cast gate (5), the 4th cold runner cast gate (6), the 5th cold runner cast gate (7), incorporate plastics to the injection of product die cavity；

3) keep each cast gate injection pressure, until product mold filling is full.

2. a kind of commercial car sky shade according to claim 1 injection molding forming method it is characterised in that: above-mentioned steps 1) In the internal needles of 2 points of hot flow paths (2) and melt chamber through increasing polishing.

3. a kind of commercial car sky shade according to claim 1 injection molding forming method it is characterised in that: it is above-mentioned that each is cold The pressure time curve of runner cast gate parabolically shape, pressure peak scope is that between 60～70mpa, pressing time is maintained at Between 30～35s.