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EP-4741133-A1 - SCREW FOR INJECTION MOLDING APPARATUS AND INJECTION MOLDING APPARATUS

EP4741133A1EP 4741133 A1EP4741133 A1EP 4741133A1EP-4741133-A1

Abstract

A screw (30) for an injection molding apparatus is for use in an injection molding apparatus. The screw (30) has: a shaft (31) that extends from a supply part to a measurement part; a groove (32) that is continuously formed in a spiral shape on the shaft (31); and a rib-like flight (33) that is formed between the grooves (32) adjacent to each other in the extension direction of the shaft (31). In the screw (30), the width of the flight (33) in the supply part is greater than the width of the flight (33) in the measurement part, the pitch of the flight (33) in the supply part is smaller than the pitch of the flight (33) in the measurement part, and the depth of the groove (32) in the supply part is greater than the depth of the groove (32) in the measurement part.

Inventors

  • KUNIHIRO, DAISUKE
  • CHIBA, HIDEKI

Assignees

  • The Japan Steel Works, Ltd.

Dates

Publication Date
20260513
Application Date
20240214

Claims (9)

  1. A screw for use in an injection molding apparatus configured to receive a raw material in a supply unit on an upstream side of the screw, convey the raw material to a measurement unit while applying heat to the raw material, and inject the melted raw material into a mold disposed on a downstream side of the measurement unit, the screw comprising: a shaft extending from the supply unit across to the measurement unit; grooves formed continuously and spirally in the shaft; and a flight having a rib-shape formed between the grooves that are adjacent to each other in an extension direction of the shaft, wherein a width of the flight in the supply unit is wider than a width of the flight in the measurement unit, a pitch of the flight in the supply unit is smaller than a pitch of the flight in the measurement unit, and a depth of the grooves in the supply unit is deeper than a depth of the grooves in the measurement unit.
  2. The screw for the injection molding apparatus according to claim 1, wherein the width of the flight in the measurement unit is 40% of the width of the flight in the supply unit.
  3. The screw for the injection molding apparatus according to claim 1, wherein the pitch of the flight in the measurement unit is 140% of the pitch of the flight in the supply unit.
  4. The screw for the injection molding apparatus according to any one of claims 1 to 3, wherein a cross-sectional area of the grooves in the supply unit parallel to the extension direction is 100 to 150% of a cross-sectional area of the grooves in the measurement unit.
  5. The screw for the injection molding apparatus according to claim 1, further comprising a compression unit disposed between the supply unit and the measurement unit, wherein the grooves in the compression unit are formed such that the grooves gradually shallow from the supply unit toward the measurement unit.
  6. The screw for the injection molding apparatus according to claim 5, wherein the flight in the compression unit is formed such that a width thereof gradually narrows from the upstream side toward the downstream side.
  7. The screw for the injection molding apparatus according to claim 5 or 6, wherein the flight in the compression unit is formed such that the pitch thereof gradually widens from the upstream side toward the downstream side.
  8. The screw for the injection molding apparatus according to claim 7, wherein an angle between the flight from the supply unit to the measurement unit and a screw shaft orthogonal cross-section is set within a range of 16 to 26 degrees.
  9. An injection molding apparatus, comprising: a heated cylinder; and a screw rotatably and protrudably-and-retractably housed in the heated cylinder, wherein the screw is rotated to knead and plasticize a raw material received in a supply unit, and the screw is caused to protrude-and-retract to thereby inject the plasticized raw material from a measurement unit toward a mold, wherein the screw comprises: a shaft extending from the supply unit across to the measurement unit; grooves formed continuously and spirally in the shaft; and a flight having a rib-shape formed between the grooves that are adjacent to each other in an extension direction of the shaft, wherein a width of the flight in the supply unit is wider than a width of the flight in the measurement unit, a pitch of the flight in the supply unit is smaller than a pitch of the flight in the measurement unit, and a depth of the grooves in the supply unit is deeper than a depth of the grooves in the measurement unit.

Description

Technical Field The present disclosure relates to a screw for injection molding apparatus and an injection molding apparatus. Background Art Various proposals have been disclosed regarding the shape of a screw in an in-line screw type injection molding apparatus. For example, an injection molding apparatus including a screw defined by a first region having a constant flight pitch, a constant groove width, and a constant groove depth and a second region having a constant flight pitch, a groove depth that becomes shallower, and a groove width that becomes wider is disclosed (Patent Literature 1). Citation List Patent Literature Patent Literature 1: Japanese Unexamined Patent Application Publication No. Publication No. 2011-224801 Summary of Invention However, in the above-described technique, the flight pitch in the tip part is determined by the shape of the screw in the region where the raw material resin is received. Therefore, in the case where a high pressure is applied to the resin at the tip of the screw, it is difficult to perform well-balanced control the backflow of the resin due to this pressure. The present disclosure has been made in order to solve such a problem, and an object of the present disclosure is to provide a screw for injection molding apparatus or the like adapted to perform desired molding optimally. A screw for an injection molding apparatus according to the present disclosure is a screw for use in an injection molding apparatus configured to receive a raw material in a supply unit on an upstream side of the screw, convey the raw material to a measurement unit while applying heat to the raw material, and inject the melted raw material into a mold disposed on a downstream side of the measurement unit. The screw for an injection molding apparatus includes: a shaft extending from the supply unit across to the measurement unit; grooves formed continuously and spirally in the shaft; and a flight having a rib-shape formed between the grooves that are adjacent to each other in an extension direction of the shaft. Regarding the screw, a width of the flight in the supply unit is wider than a width of the flight in the measurement unit, a pitch of the flight in the supply unit is smaller than a pitch of the flight in the measurement unit, and a depth of the grooves in the supply unit is deeper than a depth of the grooves in the measurement unit. An injection molding apparatus according to the present disclosure includes: a heated cylinder; and a screw rotatably and protrudably-and-retractably housed in the heated cylinder. The injection molding apparatus is configured such that the screw is rotated to knead and plasticize a raw material received in a supply unit, and the screw is caused to protrude-and-retract to thereby inject the plasticized raw material from a measurement unit toward a mold. The screw includes: a shaft extending from the supply unit across to the measurement unit; grooves formed continuously and spirally in the shaft; and a flight having a rib-shape formed between the grooves that are adjacent to each other in an extension direction of the shaft. In the screw, a width of the flight in the supply unit is wider than a width of the flight in the measurement unit, a pitch of the flight in the supply unit is smaller than a pitch of the flight in the measurement unit, and a depth of the grooves in the supply unit is deeper than a depth of the grooves in the measurement unit. According to the present disclosure, it is possible to provide a screw for an injection molding apparatus and an injection molding apparatus adapted to perform desired molding optimally. Brief Description of Drawings Fig. 1 is an overall structural view of an injection molding apparatus according to an embodiment;Fig. 2 is a partially enlarged view of a screw according to an embodiment; andFig. 3 is an external view for describing the shape of a screw. Description of Embodiments Hereinafter, the present disclosure will be described through embodiments of the disclosure, but the disclosure as claimed is not limited to the following embodiments. In addition, all of the configurations described in the embodiments are not necessarily indispensable as means for solving the problem. For clarity of explanation, the following descriptions and drawings are omitted and simplified as appropriate. In each of the drawings, the same reference symbols are assigned to the same elements, and duplicate descriptions are omitted as necessary. < Embodiment > Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is an overall structural view of an injection molding apparatus 1 according to the embodiment. A part of the injection molding apparatus 1 shown in Fig. 1 is shown as a cross-sectional view for ease of understanding. Fig. 1 shows a right-handed rectangular coordinate system for the sake of convenience in describing the positional relationship of the structural element