JP5525671B2 - Molding machine surface modified by electron beam irradiation, screw for molding machine and plunger for molding machine - Google Patents

Description

  The present invention relates to various molding machines such as injection molding machines, extrusion molding machines, and compression molding machines that use plastics and other resins or metals as molding materials, such as locations such as screws and flow paths that are in contact with the molding material. The present invention relates to a molding machine, a molding machine screw, and a molding machine plunger that are modified by irradiating the surface with an electron beam to improve the corrosion resistance and wear resistance.

In various molding machines such as injection molding machines, extrusion molding machines and compression molding machines that use plastics and other resins or metals as molding materials (herein simply referred to as “molding machines”), contact surfaces with molding materials ( For example, on the surface of a screw or molten resin flow path), as a result of physical wear or chemical corrosion due to the decomposition gas of the resin, metal powder is mixed into the molded product, or black spots, burns, contamination, yellowing in the molded product There has been a problem that various molding defects such as the above occur.
Therefore, for example, Patent Document 1 discloses an injection molding in which a thin film made of at least one of wear-resistant metal, metal oxide, metal nitride, and metal oxide is formed on a contact surface with a molding material by a dry plating method. A machine has been proposed. Further, coating by a CVD (chemical vapor deposition) method or a PVD (physical vapor deposition) method is also known.
Further, for example, in Patent Document 2, the surface of the contact with the molding material is subjected to dimple processing (sand blasting, shot peening, etc.), so that the screw surface bites into the molding material and the molding is performed on the flow path surface. There has been proposed an injection molding machine that prevents material adsorption and has improved physical and chemical characteristics with respect to wear and corrosion of the flow path surface.

JP 60-34821 A Japanese Patent No. 2577672

However, the conventional technique has the following problems.
That is, in the method of forming a thin film such as plating or coating on the contact surface with the molding material, there is a problem that pinholes are present in the thin film or the wear resistance and corrosion resistance are drastically reduced when the thin film is peeled off. There is.
In addition, there is a problem that only the dimple processing on the contact surface with the molding material cannot ensure sufficient corrosion resistance and wear resistance of the contact surface depending on the characteristics of the molding material.

  In view of such problems, the present invention modifies the surface by irradiating the contact surface with the molding material with an electron beam, and in particular, for a molding machine and a molding machine with improved corrosion resistance and wear resistance. It is an object to provide a screw and a plunger for a molding machine.

The molding machine of the present invention is a molding machine in which a molding material is plasticized, melted, kneaded, or mixed by a screw, extruded by the screw or plunger, filled in a mold, or supplied to a mold, and molded . a at least one of the surface of the surface or molding material flow path surface or a plunger of the screw, a part of or the entire part of the contact surface between the molding material, grinding or polishing, or The surface modification is performed by irradiating a large area irradiation type electron beam after performing at least one of polishing processes by buffing .
The molding machine of the present invention is a molding machine in which a molding material is plasticized, melted, kneaded, or mixed by a screw, extruded by the screw or plunger, filled in a mold, or supplied to a mold . there are, a at least one of the surface or surface or surfaces of the molding material flow path of the plunger of the screw, a part of or the entire part of the contact surface between the molding material, facilities a dimpled by irradiating an electron beam having a large area irradiation method on the in, or, a part or the whole thereof contact surface between the molding material, at least one of polishing by grinding or polishing, or buff by irradiating an electron beam having a large area irradiation method after applying the dimples on the contact surface after subjected to one, the including recesses dimpled, and wherein the surface-modified

A screw for a molding machine according to the present invention is a screw used in a molding machine for extruding a molding material, filling a mold, or supplying the mold to a mold, and forming a part of a contact surface with the molding material or The entire surface is subjected to at least one of grinding, polishing, or buffing, and the surface is modified by irradiation with an electron beam of a large area irradiation method .
A screw for a molding machine according to the present invention is a screw used in a molding machine for extruding a molding material, filling a mold, or supplying the mold to a mold, and forming a part of a contact surface with the molding material or in its entirety, the electron beam of a large area irradiation method after applying a dimple in the child irradiation, or a part or the whole thereof contact surface between the molding material, according to grinding or polishing or buff polishing the contact surface after subjected to at least one of machining by irradiating an electron beam having a large area irradiation method after applying a dimpled, said including recesses dimpled, surface modified Features.
Further, in an atmosphere of noble gas in the vacuum chamber, a voltage pulse between the cathode electrode and the irradiated body causes by applying a predetermined voltage pulse to the anode over cathode electrode to form a magnetic field with a solenoid to generate a plasma When the surface of the screw, which is the object to be irradiated, is irradiated with the electron beam generated by applying an electron beam to modify the surface, as now overlap on the front surface is partly of the screw in which the electron beam is irradiated, and wherein the shifting the range to irradiate the electron beam by a predetermined pitch.
The plunger for a molding machine according to the present invention is a plunger used in a molding machine for extruding a molding material, filling a mold, or supplying the mold to a mold, and forming a part of a contact surface with the molding material or The entire surface is subjected to at least one of grinding, polishing, or buffing, and the surface is modified by irradiation with an electron beam of a large area irradiation method .
The plunger for a molding machine according to the present invention is a plunger used in a molding machine for extruding a molding material, filling a mold , or supplying the mold to a mold, and forming a part of a contact surface with the molding material or All of them are subjected to dimple processing and then irradiated with an electron beam of a large area irradiation method , or a part or all of the contact surface with the molding material is ground or polished or polished by buffing. after the contact surface subjected to at least one of machining by irradiating an electron beam having a large area irradiation method after applying a dimpled, characterized in that said including recesses dimpled, surface modified And

Molding machine of the present invention, after applying at least one of the abrasive machining by grinding or polishing or buff the contact surface between the molding material, by irradiating an electron beam having a large area irradiation method, or by irradiation with electron beam of a large area irradiation method after applying the dimpling the contact surface between the molding material or the polishing by grinding or polishing or buff the contact surface between the molding material by irradiating an electron beam having a large area irradiation method in the contact surface after subjected to at least one of out after applying the dimples pressurized Engineering, is to modify the contact surfaces.
The contact surface for surface modification is particularly preferably a screw surface, a plunger surface, or a molding material flow path surface.
When the contact surface with the molding material is irradiated with an electron beam, a metal element (for example, chromium, molybdenum, cobalt, etc.) having high corrosion resistance and wear resistance among the materials constituting the surface is deposited on the surface layer. Corrosion resistance and wear resistance can be improved. As a result, the maintenance period and the service life of the molding machine and the parts used in the molding machine can be extended, and the cost required for these can be suppressed.

  Here, since the metal element deposited on the surface layer differs depending on the material of the contact surface, the effect of electron beam irradiation is also different. For example, in some hot tool steels, chromium contained in the material is deposited on the surface layer, so that an effect of improving heat resistance and wear resistance may be obtained. Further, in some cemented carbides, the crystal binder cobalt contained in the material is precipitated, so that an effect of improving corrosion resistance and wear resistance may be obtained. In addition, there is a case where the effect of improving the corrosion resistance and the wear resistance can be obtained with a material from which molybdenum which is a member of the chromium group element is deposited.

In addition, the surface after the modification is smoothed with a slight unevenness caused by polishing during the manufacture of the parts. That is, although the surface of the component is usually a polished surface by polishing, it is extremely finely formed with irregularities so that a plurality of grooves are aligned in the same direction, and irradiated with an electron beam of a large area irradiation system As a result, the surface of the component, in particular, the convex portion is melted and the surface is smoothed, so that heat resistance and wear resistance can be improved.

Further, the surface after the modification becomes a modified layer. Unlike the plating layer by plating, etc., the modified layer does not cover the entire surface evenly, so the peeled metal powder is mixed into the molded product, or black spots, burns, contamination, and yellowing occur in the molded product. It is possible to prevent the occurrence of various molding defects such as.
In addition, depending on the type of the molding material, the molding material that has been smoothed and melted is more slippery, and the molding material is not adsorbed on the surface, thereby improving the fluidity of the molding material.
Also, only the surface of the contact surface is modified, that is, only the surface is modified, not the material of the entire part such as screw, plunger, molding material flow path, etc. The cost required for this can be suppressed.

Note that the molding material flow path refers to a portion through which the molding material passes regardless of the mode of the molding material (solid, liquid). When a part of the molding material is vaporized, the gas contacts The part to be processed is also included in the molding material flow path.
Examples of the molding material include thermoplastic and thermosetting resins in general, metals, a mixture of metal powder and a binder (binder), and the like.

In addition, the term “screw” in the present specification refers to a member used for plasticizing, kneading or mixing at least a molding material.
Here, among the molding machines, the injection molding machine performs in-line screw injection apparatus that performs both plasticization and injection filling with a single in-line screw, and performs plasticizing with a plasticizing screw and injection filling with an injection plunger. It is roughly divided into screw prep plastic type injection devices. Therefore, when the molding machine is an injection molding machine, the “screw” includes the in-line screw and the plasticized screw.

In addition, if the surface of the contact surface is dimpled and then irradiated with an electron beam to modify the surface, including the dimpled recesses, the screw surface will bite into the molding material and the molten molding material will flow into the flow path. It is possible to obtain a synergistic effect by dimple processing that can prevent adsorption to the surface.
As a dimple processing method, a well-known method can be used as appropriate according to the property of the surface to be surface modified, such as sand blasting or shot peening.
The electron beam irradiation method is either one in which a metal element having corrosion resistance or wear resistance can be deposited on the surface of the irradiated object, or one in which slight unevenness caused by polishing or the like can be made uniform and smooth. or both not limited in particular as long as it can, but can be appropriately selected depending on the nature of the irradiated object, hereinafter, among although illustrated for a typical two schemes, the present invention large area irradiation method Is adopted.

One is represented by a technique disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-1086 and Japanese Patent Application Laid-Open No. 2006-344387, and is referred to as a “large area irradiation method” for convenience of explanation. The other is represented by a technique disclosed in, for example, Japanese Patent Application Laid-Open No. 2008-91230, and is referred to as a “scanning line method” for convenience of explanation. Here, in this specification, a case where the cross-sectional area of the electron beam to be irradiated is 10 mm 2 or more is defined as a large area irradiation method. The large-area irradiation method irradiates an electron beam with a large current at a relatively low energy density with a large cross-sectional area of the particle beam bundle. In the large area irradiation method, since the electron beam has a low energy density, the irradiated object is not eroded more than several μm from the surface. Therefore, there is an advantage that the entire surface of the irradiated body can be uniformly modified. The modified layer is uniformly formed on the surface layer of the irradiated body with a thickness of about several μm. Moreover, although the characteristic of a modified layer changes with materials of to-be-irradiated body, the durability of a metal product is improved fundamentally. Further, sharp irregularities due to grinding or polishing are substantially absent on the surface of the irradiated body.

For example, in an experiment by the present applicant, in the large area irradiation method, when the screw surface was modified, a modified layer having a thickness of about 3 μm was formed on the surface layer of the irradiated object.
In the large area irradiation method, irradiation is performed while shifting the electron beam irradiation range by a predetermined pitch. At this time, the surface that has already been modified and the surface to be irradiated with the electron beam are partially overlapped. In other words, it is preferable to perform more uniform modification by superimposing an electron beam so that a surface that is not modified or a surface that is not sufficiently modified cannot be formed.

  In the scanning line method, the particle beam bundle is focused and irradiated with an electron beam having a small cross-sectional area and a high energy density. The scanning line method has an advantage that the irradiation direction of the electron beam can be manipulated. However, since it erodes from the surface of the irradiated body to a depth of 20 μm to 30 μm, traces of scanning lines remain on the surface, and it is difficult to obtain a uniform modified surface over a wide range. In addition, it takes a long time to modify a wide area.

The figure which shows the injection mechanism of the screw prep plastic type Diagram showing inline screw type injection mechanism

  The molding machine of the present invention can be obtained by surface modification by irradiating the contact surface with the molding material with an electron beam. Therefore, the main mechanism of the molding machine is a conventional injection molding machine (for example, the injection mechanism of FIGS. 1 and 2), an extrusion molding machine (not shown), or a compression molding machine (not shown). It does not change the machine. Hereinafter, an outline of a typical molding machine will be described by taking a case of handling a thermoplastic resin material as an example.

  For example, an injection molding machine generally includes a mold clamping mechanism and an injection mechanism. The injection mechanism is roughly divided into a screw pre-plastic injection mechanism (for example, FIG. 1) and an inline screw type injection mechanism (for example, FIG. 2).

  The screw preplar type injection mechanism 10 is divided into a plasticizing unit 20 and an injection unit 30, which are connected by a connecting member 40. The plasticizing unit 20 heats the molding material supplied from the hopper 21 into the plasticizing cylinder 22 by the heater 23 wound around the outer periphery of the cylinder 22 and the plasticizing screw 24 that rotates in the cylinder 22. It is plasticized and melted by shearing heat generation and sent to the injection cylinder 33 of the injection unit 30 through the communication path 41 in the connecting member 40. In the injection unit 30, the molten molding material that has been sent is weighed at a distance that the injection plunger 31 in the injection cylinder 33 has retracted, and then the injection plunger 31 is closed with the communication path 41 closed by the backflow prevention means 42. It is advanced and injected and filled into a mold (not shown) through the injection nozzle 32. The backflow prevention means 42 is not limited to the rotary valve shown in FIG.

  The in-line screw type injection mechanism 50 is configured to heat the molding material supplied from the hopper 51 into the cylinder 52 by the heater 53 wound around the outer periphery of the cylinder 52 and to rotate in the cylinder 52. The molten molding material is plasticized and melted by the heat generated by the above process, and the molding material in a molten state is sent to the front of the in-line screw 54. Then, injection filling is performed in a mold not shown. A check ring 56 for opening and closing the flow path of the molding material at that portion is provided at the tip of the inline screw 54.

  The extrusion molding machine plasticizes and melts the molding material supplied into the cylinder by heating with a heater wound around the outer periphery of the cylinder and shearing heat generated by at least one screw provided in the cylinder. While kneading, the steel is fed forward of the screw and extruded from a die called a die at the tip of the cylinder to continuously form a molded product having a constant cross section.

  The compression molding machine includes a mold clamping mechanism and a material supply mechanism. As the material supply mechanism, for example, the injection mechanism or the extrusion molding machine of the above-described injection molding machine can be used. Therefore, the compression molding machine opens the upper mold and the lower mold by the mold clamping mechanism, advances the nozzle portion of the material supply mechanism between them, and plasticizes and melts from the upper side to the predetermined position of the lower mold. Then, the nozzle part is retracted, the mold is closed, and the molding material is compressed and molded.

  In addition, for example, a metal injection molding machine that supplies a molten metal from a melting unit that melts a metal material to an injection cylinder of an injection unit and injects it with an injection plunger in the injection cylinder, or a plurality of liquid thermosetting properties There are also liquid resin injection molding machines that mix resin with a static mixer, then supply it to the injection cylinder of the injection unit and inject it with an injection plunger in the injection cylinder, and there are various other molding machines.

The molding machine of the present invention can be obtained, for example, by surface modification by irradiating at least a part or all of the contact surface with which the supplied molding material contacts in the molding machine as described above.
The contact surface is preferably a location where wear and corrosion due to contact with the molding material can occur remarkably. For example, when the molding machine is an injection molding machine having a screw preplar type injection mechanism as shown in FIG. The surface of the screw, the surface of the injection plunger and the surface of the molding material flow path are particularly preferred.

  In the case of an injection molding machine having an inline screw type injection mechanism as shown in FIG. 2, the surfaces of the inline screw and the molding material flow path are particularly preferable.

  Further, it is preferable to modify the entire contact surface including the dimple processed concave portion by irradiating the contact surface with dimple processing and then irradiating an electron beam. At this time, the dimensions of the dimple processed recesses are formed in advance so that the recesses are not filled even when the electron beam is irradiated. Further, when dimple processing is performed on the contact surface, for example, a dimple processing is performed by colliding a projection material such as a hard sphere, so that the portion where the projection material collides is recessed and the periphery of the recessed portion is raised. The raised portion can be smoothed by electron beam irradiation performed after dimple processing. Also, for example, when dimple processing with a dimple opening dimension of about several μm (for example, a diameter dimension for a circular opening) is performed by a large area irradiation method that erodes only about a few μm of the surface layer of the contact surface. By irradiating the electron beam, it is possible to modify the surface without burying the recessed portion due to the dimple processing. Of course, the surface in the recessed portion is made uniform with slight unevenness caused by polishing or the like, and a smooth surface is formed. The opening size of the dimples may be appropriately determined depending on the molding material or the like. For example, the dimple opening size is preferably about several μm, more preferably about 2 μm.

  Here, the contact surface that comes into contact with the molding material in the molding machine is usually subjected to grinding or polishing, and in some cases, polishing by buffing according to circumstances. This is done for the purpose of improving the flowability of the molding material by preventing the molding material from adhering to the contact surface, and also for the purpose of preventing the operation of at least the rotating screw and the reciprocating plunger in the cylinder. It is often broken. Therefore, in the present invention, the electron beam is irradiated on the contact surface that has been subjected to the grinding process or the polishing process, or the dimple process is performed on the grinding process or the polishing process contact surface. It is even better if irradiation is applied. Furthermore, in the present invention, the contact surface subjected to the polishing process by the buff is irradiated with an electron beam, or the contact surface subjected to the polishing process by the buff is subjected to dimple processing. It is better to irradiate with an electron beam.

Next, a configuration example of a surface modification apparatus (not shown) when a large area irradiation method is adopted as the electron beam irradiation method will be described.
The surface modification device mainly includes a chamber, a moving device, a vacuum device, a rare gas supply device, and an electron beam generating device including a power supply device.
The chamber is a vacuum-resistant container for accommodating the irradiated object inside, and is installed on the base.

The moving device is provided for moving the irradiated body, and is schematically configured from a first moving body and a second moving body.
The first moving body moves in the X-axis direction by a known driving device such as a motor. A table (described later) is placed on the first movable body via an elevating device, and the irradiated body is fixed to the table by attaching the irradiated body directly or with a jig.
The second moving body is disposed below the first moving body, and moves in the Y-axis direction orthogonal to the X-axis direction in a horizontal plane by a known driving device such as a motor. The driving of the first moving body, the second moving body, and the lifting device is controlled by the control device.

A vacuum device is a means for bringing the inside of a sealed chamber into a state close to a vacuum. The vacuum device evacuates the air in the chamber by a vacuum pump, and decompresses the inside of the chamber by so-called evacuation. The vacuum pump evacuates the chamber while irradiating the irradiated body with the electron beam, and maintains a state close to vacuum.
The rare gas supply device is means for supplying a rare gas into the chamber. As the rare gas (inert gas), helium, neon, argon, krypton, xenon, and radon, which are Group 18 elements of the long periodic table, can be cited, but argon gas is often used in the surface modification method using an electron beam. .

The electron beam generator includes a cathode electrode that is an electron gun, an annular anode electrode, a table (collector) for energizing the irradiated object, and a solenoid for forming a magnetic field.
The table is grounded to the chamber by a ground line. In addition, an electron beam generating power supply device is provided between the electrode of the table and the object to be energized and the cathode electrode, and an electron beam is generated by applying a voltage pulse between the electrodes using a high voltage power source.
The anode electrode has a function of generating plasma for converging the electrons so that the irradiated electrons are not scattered, and a plasma generating power supply device is provided between the anode electrode and the table.

Next, an electron beam irradiation method using the surface modification apparatus will be described.
First, the inside of a clean chamber is evacuated to supply a rare gas. Next, a magnetic field is formed by a solenoid, and a predetermined voltage pulse is applied to the anode electrode to generate plasma. A voltage pulse is applied between the cathode electrode and the collector (object to be irradiated) to generate an electron beam. The soot remaining in the chamber is removed after several electron beam irradiations.

  The surface modification apparatus described above and the electron beam irradiation method using the apparatus are only examples, and are not limited thereto. Other than the above examples, depending on the nature and shape of the irradiated object to be irradiated with the electron beams. The structure of the surface modification apparatus in the large area irradiation method and the electron beam irradiation method may be applied. Further, the surface modification device and the electron beam irradiation method by the device are not limited to the large area irradiation method, and can deposit a metal element having corrosion resistance and wear resistance on the surface of the irradiated object, or There is no particular limitation as long as one or both of the slight unevenness caused by polishing or the like can be made uniform and smooth.

  The present invention modifies the surface by irradiating the contact surface with the molding material with an electron beam, in particular, a molding machine with improved corrosion resistance and wear resistance, a screw for the molding machine, and a molding machine. And has industrial applicability.

DESCRIPTION OF SYMBOLS 10 Screw preparation type injection mechanism 20 Plasticizing unit 21 Hopper 22 Plasticizing cylinder 23 Heater 24 Plasticizing screw 30 Injection unit 31 Injection plunger 32 Injection nozzle 33 Injection cylinder 40 Connecting member 41 Communication path 42 Backflow prevention means 50 In-line screw type Injection mechanism 51 Hopper 52 Cylinder 53 Heater 54 In-line screw 55 Injection nozzle 56 Check ring

Claims (7)

In a molding machine in which a molding material is plasticized, melted, kneaded, or mixed by a screw, extruded by the screw or plunger, filled into a mold, or supplied to a mold, and molded .
A at least one of the surface or surface or surfaces of the molding material flow path of the plunger of the screw, a part or the whole thereof contact surface between the molding material, grinding or polishing, or A molding machine characterized by performing surface modification by irradiating a large area irradiation type electron beam after performing at least one of polishing processes by buffing . Oite molding material plasticized molten or kneaded or mixed by the screw, to a molding machine for molding by supplying the filling with or mold extrusion or mold by the screw or plunger,
At least one of the surface of the screw, the surface of the plunger, or the surface of the molding material flow path , and dimple processing is performed on a part or all of the contact surface with the molding material. by irradiating an electron beam having a large area irradiation method, or a part or the whole thereof contact surface between the molding materials were subjected to at least one polishing sac Chino by grinding or polishing, or buff by irradiating an electron beam having a large area illumination scheme after applying the dimple after said contact surface, forming machine, wherein the including recesses dimpled, surface modified. In a screw used in a molding machine for extruding a molding material or filling a mold or supplying a mold to a mold,
Surface modification by irradiating a part or all of the contact surface with the molding material with at least one of grinding, polishing, or buffing and then irradiating a large area irradiation electron beam. A screw for a molding machine characterized by the above. In a screw used in a molding machine for extruding a molding material or filling a mold or supplying a mold to a mold,
Some or all its contact surface with the molding material, by irradiating an electron beam having a large area irradiation morphism scheme after applying the dimple, or part of the contact surface between the molding material or its all in, by irradiating an electron beam having a large area irradiation method after applying the dimples on the contact surface after subjected to at least one of polishing by grinding or polishing or buffing, the dimpled A screw for a molding machine, which is surface-modified including the concave portion of the molding machine. In a rare gas atmosphere in a vacuum chamber, a magnetic field is formed by a solenoid to produce anode current. A predetermined voltage pulse is applied to the poles to generate plasma and the cathode electrode and irradiated object The electron beam generated by applying a voltage pulse between the When surface modification is performed by irradiating the surface of the screw, the surface modification is already performed by irradiating the electron beam. The surface of the screw and the surface of the screw to be irradiated with the electron beam The range in which the electron beam is irradiated is shifted by a predetermined pitch so as to partially overlap A screw for a molding machine according to claim 3 or 4. In a plunger used in a molding machine for extruding a molding material or filling a mold or supplying a mold to a mold,
Surface modification by irradiating a part or all of the contact surface with the molding material with at least one of grinding, polishing, or buffing and then irradiating a large area irradiation electron beam. A plunger for a molding machine. In the plunger it is found using a molding machine for molding is supplied to and filled in extruding the molding material or mold or mold,
Some or all its contact surface with the molding material, by irradiating an electron beam having a large area irradiation morphism scheme after applying the dimple, or part of the contact surface between the molding material or its of the total, by irradiating an electron beam having a large area irradiation method after applying the dimples on the contact surface after subjected to at least one of polishing by grinding or polishing or buffing, the dimples A plunger for a molding machine, characterized by surface modification including a concave portion for processing.

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