Cylinder for injection molding apparatus, and injection molding apparatus

Abstract

To provide a cylinder for an injection molding apparatus that enhances heater efficiency by contriving structure of the injection molding apparatus, particularly structure of the cylinder.SOLUTION: A cylinder is used in an injection molding apparatus in which a raw material is introduced to the inside, and conveyed while the raw material is heated by a screw installed inside, and the molten raw material is injected into a mold provided on the downstream side. The cylinder is provided with a heater having a cylindrical shape concentric with the screw, and covering an outer surface of the cylinder to heat the cylinder. A ratio of a surface roughness Ra (μm) of the cylinder to the outer diameter (mm) of the cylinder is 0.002 to 0.050.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a cylinder for an injection molding apparatus and an injection molding apparatus. [Background technology]

[0002] An injection molding device with improved thermal efficiency of the heater has been developed. Patent Document 1 describes that the converter of the electric injection molding machine is composed of a PWM converter equipped with a reactor. This PWM converter rectifies and boosts an external three-phase AC voltage to convert it into a predetermined primary DC voltage. This primary DC voltage is supplied to a servo amplifier that drives a servo motor. A chopper circuit is connected to the voltage line of the primary DC voltage, and the primary DC voltage is boosted to obtain a secondary DC voltage. Power from this secondary DC voltage is supplied to the heater of the electric injection molding machine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-223975 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the method of improving the thermal efficiency of the heater in Patent Document 1 involves changing the power supply method, and does not improve efficiency due to the structure of the injection molding device. Therefore, the object of the present disclosure is to provide a cylinder for an injection molding device that improves the thermal efficiency of the heater by improving the structure of the injection molding device, particularly the structure of the cylinder.

[0005] Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. [Means for solving the problem]

[0006] According to one embodiment, by adjusting the surface roughness of the cylinder, it is possible to improve the adhesion with the heater and increase the efficiency of heat conduction from the heater. Effect of the Invention

[0007] According to the embodiment, it is possible to provide a cylinder for an injection molding device that improves the thermal efficiency of the heater by improving the structure of the injection molding device, particularly the structure of the cylinder. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of an injection molding apparatus according to an embodiment. [Diagram 2] FIG. 2 is a schematic diagram of a cylinder and a heater of the injection molding device according to the embodiment. [Diagram 3] FIG. 2 is a cross-sectional view of a cylinder of the injection molding device according to the embodiment. [Figure 4] FIG. 13 is a diagram showing an example of average power of the heater and motor of a related injection molding machine. [Diagram 5] FIG. 11 is a diagram showing the relationship between the surface roughness and the temperature rise time of a cylinder of the injection molding device according to the embodiment. [Figure 6] FIG. 4 is a diagram showing the relationship between the surface roughness and the surface area of ​​a cylinder according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the invention according to the claims is not limited to the following embodiment. Furthermore, not all of the configurations described in the embodiment are necessarily essential as means for solving the problem. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. In each drawing, the same elements are given the same reference numerals, and repeated explanations are omitted as necessary.

[0010] (Description of Injection Molding Apparatus According to an Embodiment) FIG. 1 is a schematic diagram of an injection molding apparatus according to an embodiment. FIG. 2 is a schematic diagram of a cylinder and a heater of the injection molding apparatus according to an embodiment. FIG. 3 is a cross-sectional view of the cylinder of the injection molding apparatus according to an embodiment. The injection molding apparatus according to an embodiment will be described with reference to FIG. 1 to FIG. 3. The injection molding apparatus according to an embodiment is a machine that heats and melts raw materials such as unmolded objects containing resin, and injects the melted raw materials into a mold to form a molded object.

[0011] 1 to 3, an injection molding apparatus 100 includes a cylinder 101 and a heater 102. The injection molding apparatus 100 feeds and injects a raw material into a tip 104 of the cylinder 101. The injected raw material is poured into a mold to form a molded product.

[0012] As shown in FIG. 3, the cylinder 101 has a hollow cylindrical shape and is provided with a screw (not shown) disposed inside coaxially with the outer surface of the cylinder. Raw material is introduced into the cylinder 101 from a hopper 103 and transported by the rotation of the screw. The raw material is heated and melted in the cylinder 101. The raw material is kneaded and plasticized by the rotation of the screw, and is pushed out from the rear where the hopper 103 is located toward the tip 104. The raw material is accumulated downstream of the screw as it rotates and retreats, and is injected from the tip 104 of the cylinder by the injection action of the screw. In other words, the plasticized raw material is injected toward the mold by moving the screw back and forth.

[0013] 2, the heater 102 is attached in a manner of being wound around the cylinder 101 in a number of turns to cover the circumference of the cylinder 101, and is a heater for heating the cylinder 101. The heater 102 can heat the cylinder 101 up to 650° C. The raw material in the cylinder 101 is heated and melted by the heat generated by the heater 102. The heater 102 is preferably a band heater, but is not limited to this, and any heater that heats the cylinder 101 by contacting it can be used. For example, the heater 102 can be a cartridge heater, a cast heater, a space heater, or a silicon rubber heater.

[0014] (Explanation of Surface Roughness of Cylinder According to the Embodiment) Fig. 4 is a diagram showing an example of average power of a heater and a motor of a related injection molding device. Fig. 5 is a diagram showing the relationship between the surface roughness and the temperature rise time of a cylinder of an injection molding device according to an embodiment. Fig. 6 is a diagram showing the relationship between the surface roughness and the surface area of ​​a cylinder according to an embodiment. The surface roughness of a cylinder according to an embodiment will be described with reference to Figs. 4 to 6.

[0015] As shown in Figure 4, the power consumed by the heater and the motor in the related injection molding machine is almost equal. Therefore, if the power of the heater can be reduced, the power consumed by the injection molding machine can be significantly reduced.

[0016] As shown in Fig. 5, when the surface roughness Ra (μm) of the cylinder 101 is changed from 6.3 to 3.2 and 1.6, the temperature rise time is shortened from 1 to 0.98 and 0.95. In other words, the thermal efficiency of the heater is improved. Furthermore, by changing the surface roughness Ra (μm) to 0.8, the thermal efficiency of the heater is improved.

[0017] As shown in Fig. 6, the reason why the thermal efficiency of the heater improves when the surface roughness Ra is reduced is believed to be that the unevenness of the surface becomes smaller when Ra is reduced. This is because the surface area in contact with the heater 102 increases when the unevenness of the surface of the cylinder 101 is reduced. This improves the adhesion between the cylinder 101 and the heater 102, and improves the efficiency of heat conduction from the heater 102 to the cylinder 101.

[0018] The surface roughness Ra of the cylinder 101 can be set within a range depending on the outer diameter of the cylinder. When the outer diameter of the cylinder is 100 mm or less, the ratio of the surface roughness Ra (μm) to the outer diameter (mm) of the cylinder can be machined with an accuracy of 0.008 to 0.050. When the outer diameter of the cylinder is greater than 100 mm and less than 200 mm, the ratio of the surface roughness Ra (μm) to the outer diameter (mm) of the cylinder can be machined with an accuracy of 0.004 to 0.030. When the outer diameter of the cylinder is greater than 200 mm and less than 300 mm, the ratio of the surface roughness Ra (μm) to the outer diameter (mm) of the cylinder can be machined with an accuracy of 0.002 to 0.020. When the outer diameter of the cylinder is greater than 300 mm, the ratio of the surface roughness Ra (μm) to the outer diameter (mm) of the cylinder can be machined with an accuracy of 0.002 to 0.009. In this way, by changing the outside diameter of the cylinder 101 and machining the surface, the ratio of the surface roughness Ra (μm) of the cylinder to the outside diameter of the cylinder can be machined with an accuracy of 0.002 to 0.050.

[0019] In this way, the above-mentioned configuration provides a cylinder for an injection molding device, which improves the thermal efficiency of the heater by improving the structure of the injection molding device, particularly the structure of the cylinder. By improving the thermal efficiency of the heater, it is possible to reduce the power consumed by the injection molding device.

[0020] The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0021] 100 injection molding device, 101 cylinder, 102 heater, 103 hopper, 104 tip

Claims

1. A cylinder for use in an injection molding device in which a raw material is introduced into the cylinder, the raw material is heated and transported by a screw installed inside the cylinder, and the molten raw material is injected into a mold installed downstream, The cylinder has a cylindrical shape coaxial with the screw, a heater covering an outer surface of the cylinder and heating the cylinder; A cylinder for an injection molding apparatus, wherein the ratio of the surface roughness Ra (μm) of the cylinder to the outer diameter (mm) of the cylinder is 0.002 to 0.

050.

2. 2. The cylinder for an injection molding apparatus according to claim 1, wherein the surface roughness Ra (μm) of the cylinder is 0.8 to 3.

2.

3. 2. The cylinder for an injection molding apparatus according to claim 1, wherein the heater is a band heater, a cartridge heater, a cast-in heater, a space heater, or a silicon rubber heater.

4. 2. The cylinder for an injection molding apparatus according to claim 1, wherein the heater heats the cylinder up to 650°C.

5. 5. A cylinder for an injection molding apparatus according to claim 1, wherein when the outer diameter of the cylinder is 100 mm or less, the ratio of the surface roughness Ra (μm) of the cylinder to the outer diameter (mm) of the cylinder is 0.008 to 0.

050.

6. 5. A cylinder for an injection molding apparatus according to claim 1, wherein when the outer diameter of the cylinder is greater than 100 mm and not greater than 200 mm, the ratio of the surface roughness Ra (μm) of the cylinder to the outer diameter (mm) of the cylinder is 0.004 to 0.

030.

7. 5. A cylinder for an injection molding apparatus according to claim 1, wherein when the outer diameter of the cylinder is greater than 200 mm and not greater than 300 mm, the ratio of the surface roughness Ra (μm) of the cylinder to the outer diameter (mm) of the cylinder is 0.002 to 0.

020.

8. 5. A cylinder for an injection molding apparatus according to claim 1, wherein when the outer diameter of the cylinder is greater than 300 mm, the ratio of the surface roughness Ra (μm) of the cylinder to the outer diameter (mm) of the cylinder is 0.002 to 0.

009.

9. An injection molding apparatus having a cylinder with a heater attached to its outer surface, a screw installed inside the cylinder and coaxial with the outer surface of the cylinder, kneading and plasticizing a raw material by rotating the screw, and injecting the plasticized raw material into a mold by moving the screw back and forth, The cylinder of the injection molding apparatus has a ratio of the surface roughness Ra (μm) of the cylinder to the outer diameter (mm) of the cylinder of 0.002 to 0.050.

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