JP2015101076A - Injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection molding machine in which a resin material is fed in a heating cylinder and in which feeding of unfavorable gas to the heating cylinder is suppressed when the injection molding machine produces a molded article.SOLUTION: The injection molding machine includes a heating cylinder 3 for melting a resin material, and a resin material feeding device 6 for feeding the resin material to the heating cylinder 3. The resin material feeding device 6 comprises: a pump 12 generating a suction force by being driven; a charge hopper 9 in which the resin material is charged by the suction force generated by the drive of the pump 12; an openable/closable airtight valve 10 provided at the lower part of the charge hopper 9; and a feeding hopper 11 to which the resin material charged in the charge hopper 9 through the airtight valve 10 is fed. The molding machine suppresses feeding of unfavorable gas together with the resin material into the heating cylinder 3 by feeding the resin material into the cylinder 3 in such a state that the inside of the feeding hopper 11 and that of the cylinder 3 communicating with the inside of the feeding hopper 11 are put into a vacuum state by the drive of a vacuum pump 20.

Description

  The present invention relates to an injection molding machine in which a resin material that can be a raw material of a molded body is supplied into a heating cylinder, and in particular, when a molded body is manufactured by an injection molding machine, a defective gas is generated in the resin material supplied to the heating cylinder. The present invention relates to an injection molding machine capable of suppressing inclusion.

  In a general injection molding machine that has been used in the past, a granular thermoplastic resin (pellet) as a raw material is fed into a heating cylinder, and the resin is melted by a reciprocating screw provided in the heating cylinder. Sending out to the nozzle side of the screw tip, injecting molten resin from the injection nozzle provided on the screw tip side into the cavity of the mold apparatus, cooling the molten resin in the cavity and solidifying, then opening the mold apparatus, A molded product is molded by removing a molded product attached to the mold with a protruding pin or the like from the mold.

  In an injection molding machine that molds a molded body such as plastic, when the thermoplastic resin put into the hopper is heated and melted in a heating cylinder, defects such as water vapor and volatile gas contained in the thermoplastic resin Gas is generated. And it is known that resin burns etc. will arise in the manufactured molded article and it will produce a defective article.

  Those related to the above technique are disclosed in Patent Documents 1 and 2. Patent Document 1 has the following description of a melt molding machine 1 such as an injection molding machine or an extrusion molding machine. A cylindrical supply cylinder port 15 is provided at the lower end of the supply hopper 10 for charging the resin into the cylinder 4. The lower end portion of the supply tube port portion 15 is connected in close contact with the inner peripheral surface of the receiving port 7 of the cylinder 4. At the upper end portion of the supply cylinder port portion 15, a connection pipe 11 connected in close contact with the lower portion of the supply hopper 10 is provided. The connecting pipe 11 is provided as a double cylinder structure so as to cover the outer periphery of the supply cylinder port 15 at a predetermined interval. Thereby, it is possible to reliably remove the defective gas from between the connecting pipe 11 and the supply cylinder port portion 15 while stably supplying the resin from the supply tube port portion 15.

  In addition, Patent Document 2 discloses a resin raw material supply device for a synthetic resin molding machine for the purpose of removing gas generated in a casing of a heating cylinder during a weighing process by using a rinsing effect by the atmosphere or the like. It is disclosed. In order to achieve the above object, the resin raw material supply device for the synthetic resin molding machine is connected to the raw material inlet of the heating cylinder composed of a screw and a casing and the raw material inlet, and the raw material is supplied to the heating cylinder. A raw material charging inner cylinder part, a damper provided above the raw material charging inner cylinder part, and the raw material charging inner cylinder part between the raw material charging inner cylinder part and the damper, An atmosphere introduction port communicated with, an atmosphere release valve connected to the atmosphere introduction port, and a material suction inner cylinder portion are disposed so as to surround the gas introduction port, and a lower end opening portion is provided with the material introduction port. It is described that it includes an exhaust outer cylinder portion that is communicated with, and a control means that receives a predetermined control signal and controls the opening of the air release valve.

JP 2003-103522 A Japanese Patent No. 412995

  The present invention has been made in view of the above problems, and in an injection molding machine in which a resin material that can be a raw material of a molded body is supplied into a heating cylinder, a defective gas is produced when the injection molding machine manufactures the molded body. An object of the present invention is to provide an injection molding machine that can prevent the resin material supplied to the heating cylinder from being included in the resin material.

Invention of defective gas removal method in this injection molding machine,
A heating cylinder that melts the resin material, a resin material supply device that supplies the resin material to the heating cylinder, and the resin material that is attached to the tip of the heating cylinder and is melted by the heating cylinder into the cavity of the mold In an injection molding machine comprising: an injection nozzle that injects, and a screw that is provided inside the heating cylinder and that sends the molten resin material to the injection nozzle side,
The resin material supply device includes a pump that generates a suction force by driving, a charging hopper that is charged with a resin material by the suction force generated by driving the pump, and an openable and closable seal provided at a lower portion of the charging hopper A proximity switch for detecting whether or not the resin material supplied to the supply hopper is in a predetermined amount, a supply hopper supplied with the resin material supplied to the input hopper via the sealing valve, A vacuum pump that evacuates the inside of the supply hopper,
In order from top to bottom, the charging hopper, the opening / closing valve, the supply hopper, and the heating cylinder are disposed,
By supplying the resin material into the heating cylinder in a state where the inside of the supply hopper and the inside of the heating cylinder communicating with the inside of the supply hopper are in a vacuum state by driving the vacuum pump, It is characterized by suppressing supply of defective gas.

  Furthermore, the defective gas removal method of the present injection molding machine is characterized in that a glass tube is provided below the supply hopper, and the proximity switch is provided on the glass tube.

  Furthermore, the invention of a defective gas removal method in the present injection molding machine is provided with a material dropping port at a lower portion of the glass tube, and an inclined notch is formed at a rear portion of the material dropping port, whereby the supply hopper, The resin material supplied into the heating cylinder from the material dropping port via a glass tube can be supplied smoothly.

  According to the present invention, the resin material is supplied from the supply hopper to the heating cylinder in a state where the supply hopper and the heating cylinder communicating with the supply hopper are in a vacuum state. When the gas is supplied to the heating cylinder, it is possible to prevent the defective gas from being supplied into the heating cylinder together with the resin material. Therefore, it is possible to prevent defects such as resin burning from occurring in the manufactured molded product, and a high-quality molded product can be obtained.

It is a block diagram which shows the injection unit comprised in the injection molding machine of Example 1. It is sectional drawing which shows the principal part of the injection unit comprised in the injection molding machine of Example 1. It is sectional drawing which shows the principal part of the injection unit comprised in the injection molding machine of Example 2.

  Embodiments of the present invention will be described below with reference to FIGS. Needless to say, the present invention can be easily applied to configurations other than those described in the embodiments without departing from the spirit of the invention.

  An injection unit 1 configured in the injection molding machine of Example 1 shown in FIG. 1 includes a cylindrical heating cylinder 3 fixed to a hopper block 2, an injection nozzle 4 attached to the tip of the heating cylinder 3, and a heating cylinder 3. A screw 5 provided rotatably inside, and a resin material supply device 6 for supplying a resin material such as a thermoplastic resin as a raw material of a molded body to be manufactured to the heating cylinder 3 are provided.

  The resin material supply device 6 includes, in order from the top to the bottom, a pipe 7 for transporting the resin material, a charging hopper 9 provided with an air suction port 8 on the side, an openable / closable sealing valve 10, a supply hopper 11, and a glass tube 13. The material dropping port 23 is disposed, and a pump 12 is connected to the air suction port 8 of the charging hopper 9.

  The cylindrical glass tube 13 provided below the supply hopper 11 is disposed so as to face the cylindrical sleeve 15 fitted to the peripheral edge of the hole 14 formed in the hopper block 2. ing. The material dropping port 23 provided in the lower part of the glass tube 13 is inserted into a hole 16 formed in the upper part of the heating cylinder 3. The resin material charged into the charging hopper 9 from the pipe 7 is supplied from the charging hopper 9 into the heating cylinder 3 through the sealable valve 10 that can be opened and closed, the supply hopper 11, the glass tube 13, and the material dropping port 23. The The glass tube 13 below the supply hopper 11 is made of glass in order to prevent adverse effects due to static electricity.

  A proximity switch 17 as a sensor is provided on the side of the glass tube 13. The proximity switch 17 detects whether or not a predetermined amount of resin material is present in the glass tube 13. By this detection, it is possible to detect whether or not a predetermined amount of the resin material is in the supply hopper 11.

  At the upper part of the hopper block 2, a flange portion 18 is provided for holding a glass tube 13 in which the supply hopper 11 is integrally provided. A suction port 19 that communicates with the inside of the glass tube 13 is formed in the flange portion 18. Then, the vacuum pump 20 connected to the suction port 19 is driven in a state where the sealing valve 10 is closed, so that the inside of the glass tube 13 and the supply hopper 11 communicating with the inside of the glass tube 13, the material dropping port The inside of 23 becomes a vacuum state. On the other hand, when releasing the vacuum state, the atmosphere release valve 21 provided on the side of the sealing valve 10 is opened, so that the atmosphere release valve 21 can supply the inside of the supply hopper 11, the glass tube 13, the material drop port. Air is flowed into 23.

  Further, as shown in FIG. 2, an inclined notch 22 is formed at the rear of the material dropping port 23 arranged so as to be inserted through the hole 16 of the heating cylinder 3. The notch portion 22 of the material dropping port 23 will be described as being based on the front side of the screw 5 as the front side and the opposite side as the rear side. It is formed obliquely upward. The inclination angle of the notch 22 is 40 degrees in the first embodiment, but may be appropriately selected within a range of 12.5 degrees to 45 degrees. Further, the material dropping port 23 is near the upper part of the screw 5. Further, since the material dropping port 23 is provided with the notch 22 so that the material dropping port 23 can be spread rearward, the resin is smoothly supplied to the heating cylinder 3. It becomes possible.

  Next, an operation when the resin material is supplied into the heating cylinder 3 will be described. When the vacuum pump 20 is driven in a state in which the hermetic valve 10 is closed, the proximity switch when the inside of the supply hopper 11, the inside of the glass tube 13 communicating therewith, the inside of the material dropping port 23, etc. is in a vacuum state. 17 detects that the resin material is not present in the glass tube 13, the air release valve 21 is opened and the sealing valve 10 is opened based on the detection, and air is supplied from the atmosphere release valve 21 through the sealing valve 10. In addition to the inside of the charging hopper 9, it flows into the supply hopper 11, the glass tube 13 communicating therewith, the material dropping port 23, and the like.

  Next, when the pump 12 is driven, as the air in the charging hopper 9 is exhausted to the outside from the air suction port 8, the resin material is externally connected to the pipe 7, the charging hopper 9, the sealing valve 10, It is conveyed into the heating cylinder 3 through the supply hopper 11, the glass tube 13, and the material dropping port 23.

  When the proximity switch 17 detects that there is a predetermined amount of resin material in the glass tube 13, both the air release valve 21 and the sealing valve 10 are closed, and then the vacuum pump 20 is driven, and the inside of the supply hopper 11, The inside of the glass tube 13, the material dropping port 23, and the inside of the heating cylinder 3 communicating with these are evacuated.

  Then, in the state where the inside of the supply hopper 11, the inside of the glass tube 13, the inside of the material dropping port 23, and the inside of the heating cylinder 3 communicating with these are evacuated, the resin material included in the material dropping port 23 is heated by the heating cylinder being heated. 3, the resin material is conveyed to the injection nozzle 4 side at the tip end side of the screw 5 according to the rotation of the screw 5, and after a predetermined amount of the resin material is measured, the injection nozzle 4 Then, the molten resin material is injected and filled into the cavity of the clamped mold, and the molded body is molded.

  According to the injection molding machine of the present embodiment as described above, resin is supplied from the supply hopper 11 to the heating cylinder 3 with the inside of the supply hopper 11 and the inside of the heating cylinder 3 communicating with the inside of the supply hopper 11 being in a vacuum state. Since the material is supplied, when the resin material is supplied from the resin material supply device 6 to the heating cylinder 3, it is possible to prevent the defective gas from being supplied into the heating cylinder 3 together with the resin material. Therefore, it is possible to prevent defects such as resin burning from occurring in the manufactured molded product, and a high-quality molded product can be obtained.

  FIG. 3 shows a main part of an injection unit configured in the injection molding machine according to the second embodiment. The flange portion 18 in Example 2 is formed with a nitrogen inlet 24 communicating with the inside of the glass tube 13, and other than that has the same configuration as the injection molding machine of Example 1, so that The same parts as those in Example 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the first embodiment, the vacuum pump 20 is driven to evacuate the inside of the supply hopper 11, the glass tube 13, the material dropping port 23, and the heating cylinder 3 communicating with them. Instead, when the vacuum pump 20 is driven, the feed hopper 11, the glass tube 13, the material dropping port 23, and the heating cylinder 3 communicating with these are supplied from the outside through the nitrogen inlet 23. Nitrogen is supplied. Even in such a method, it is possible to prevent the resin material from containing a defective gas, and a high-quality molded article can be obtained.

DESCRIPTION OF SYMBOLS 1 Injection unit 2 Hopper block 3 Heating cylinder 4 Injection nozzle 5 Screw 6 Resin material supply apparatus 7 Piping 8 Air suction port 9 Feeding hopper 10 Sealing valve 11 Supply hopper 12 Pump 13 Glass tube 14 Hole 15 Sleeve 16 Hole 17 Proximity switch 18 Flange portion 19 Suction port 20 Vacuum pump 21 Atmospheric release valve 22 Notch portion 23 Material drop port 24 Nitrogen inlet

Claims (3)

A heating cylinder that melts the resin material, a resin material supply device that supplies the resin material to the heating cylinder, and the resin material that is attached to the tip of the heating cylinder and is melted by the heating cylinder into the cavity of the mold In an injection molding machine comprising: an injection nozzle that injects, and a screw that is provided inside the heating cylinder and that sends the molten resin material to the injection nozzle side,
The resin material supply device includes a pump that generates a suction force by driving, a charging hopper that is charged with a resin material by the suction force generated by driving the pump, and an openable and closable seal provided at a lower portion of the charging hopper A proximity switch for detecting whether or not the resin material supplied to the supply hopper is in a predetermined amount, a supply hopper supplied with the resin material supplied to the input hopper via the sealing valve, A vacuum pump that evacuates the inside of the supply hopper,
In order from top to bottom, the charging hopper, the opening / closing valve, the supply hopper, and the heating cylinder are disposed,
By supplying the resin material into the heating cylinder in a state where the inside of the supply hopper and the inside of the heating cylinder communicating with the inside of the supply hopper are in a vacuum state by driving the vacuum pump, A method for removing a defective gas in an injection molding machine, wherein the supply of the defective gas is suppressed.   2. The method for removing a defective gas in an injection molding machine according to claim 1, wherein a glass tube is provided below the supply hopper, and the proximity switch is provided on the glass tube.   A material drop port is provided at the lower part of the glass tube, and an inclined notch is formed at the rear part of the material drop port, so that the material drop port is inserted into the heating cylinder through the supply hopper and the glass tube. The method for removing a defective gas in an injection molding machine according to claim 2, wherein the resin material to be supplied can be supplied smoothly.

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