Sectional variable pitch screw

A variable pitch and segmented technology, applied in the segmented variable pitch screw field, can solve the problems of easy back-overflow, decrease of the strength index of molded products, reduction of glass fiber reinforcement, etc., so as to avoid backflow and have a simple structure. , the effect of improving quality

Inactive Publication Date: 2012-12-05
MILIKUDO GLASS FIBER REINFORCED PLASTIC TAIZHOU
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When extruding BMC with a commercially available screw extruder, due to the fixed-pitch structure of the screw, it is easy to reverse the overflow during extrusion. The reverse overflow causes the glass fiber contained in it to be torn off, and the damaged glass fiber reduces the original reinforcement. function, so that the strength index of subsequent molded products will decrease
If the incremental glass fiber is reserved in the combination, the torn glass fiber can be compensated, but the production cost is increased, so this method is rarely used
In addition, there is still a big disadvantage when commercially available screw extruders extrude BMC, that is, the fixed-pitch screw has a zero compression ratio during extrusion, and the density of the extruded BMC paste material is not enough, which makes the subsequent molded products The quality index does not meet the design requirements

Method used

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  • Sectional variable pitch screw

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Embodiment Construction

[0012] The present invention will be further described below according to the accompanying drawings and in conjunction with the embodiments.

[0013] figure 1 The segmented variable-pitch screw shown is an externally threaded straight rod member with a pitch of 100mm to 140mm and a tooth height of 14mm to 23mm. To the end, it is successively divided into conveying section A, feeding section B, compression section C and extrusion section D. The conveying section A is provided with 5 to 7 teeth, the feeding section B is provided with 2 to 3 teeth, and the axial cross-sectional area of ​​each tooth in the feeding section B is 20% to 30% larger than the axial cross-sectional area of ​​each tooth in the conveying section A. %. The compression section C is provided with 2-3 teeth, and the axial cross-sectional area of ​​each tooth is 20%-30% smaller than that of the feed section B. The extrusion section D is equipped with 3 to 5 teeth, and the parameters of each tooth shaft are d...

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Abstract

The invention discloses a sectional variable pitch screw, which is an outer screw thread straight rod member with a pitch of 100-140 mm and a tooth height of 14-23 mm, and is sequentially divided into a conveying section A, a feeding section B, a compression section C and an extrusion section D from the root to the end of the screw. The conveying section A is provided with 5-7 teeth, and the feeding section B is provided with 2-3 teeth, wherein an axial section area of each tooth of the feeding section B is 20-30% larger than an axial section area of each tooth of the conveying section A. The compression section C is provided with 2-3 teeth, wherein an axial section area of each tooth of the compression section C is 20-30% smaller than an axial section area of each tooth of the feeding section B. The extrusion section D is provided with 3-5 teeth, wherein parameters of various teeth are different, pitches are sequentially increased, tooth heights are sequentially decreased, axial section areas of various teeth of the extrusion section D are maintained to the same, and the section area is equal to an axial section area of each tooth of the extrusion section D. With the screw having a differentiation structure design, pasty BMC produces a kneading effect during extrusion, such that BMC homogenization is promoted, the material can not overflow in a reverse direction, and glass fibers in the pasty BMC can not be broken without reason.

Description

technical field [0001] The invention relates to a screw of a screw extruder, in particular, the invention relates to a segmented variable-pitch screw of a screw extruder. Background technique [0002] In the production of plastic molded products, the raw materials are usually smelted first, and then the paste-like raw materials are injected into the mold through the screw extruder. BMC is a glass fiber-reinforced unsaturated polyester bulk molding compound. This type of plastic is a new type of contemporary engineering plastic. Compared with ordinary plastics, its physical properties are quite different. Product structural strength. The heat resistance of glass fiber is between 450°C and 500°C, and the melting temperature of BMC is only about 230°C, so the contained glass fiber will not be melted. When extruding BMC with a commercially available screw extruder, due to the fixed-pitch structure of the screw, it is easy to reverse the overflow during extrusion. The reverse o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B29C47/60B29C48/535B29C48/395
CPCB29C47/38B29C47/6025B29C48/395B29C48/535
Inventor 王学军
Owner MILIKUDO GLASS FIBER REINFORCED PLASTIC TAIZHOU
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