JPH07256718A - Lining cylinder for injection molding machine and production thereof - Google Patents

Abstract

PURPOSE:To enhance the abrasion resistance and corrosion resistance of the resin contact parts such as the inner surface or end part of the cylinder, the port of the hopper or the like of an injection molding machine. CONSTITUTION:In the lining cylinder for an injection molding machine, a corrosion and abrasion-resistant lining layer is formed to the inner surface of a cylinder and a corrosion-resistant material is applied and bonded to the resin affecting part of the cylinder. The corrosion-resistant material is closely bonded and arranged to the surface of the resin affecting part of the cylinder and corrosion and abrasion-resistant lining is applied to the inner surface of the cylinder by a hot static pressure press to diffuse and bond the corrosion-resistant material to the surface of the resin affecting part. By this constitution, corrosion and abrasionresistant coatings 6, 7, 8 good in durability can be inexpensively applied to the inner surface of the cylinder 1, the end part 2 of the cylinder and the hopper port 2 of the injection molding machine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding machine in which a corrosion- and abrasion-resistant lining layer is formed on the inner surface of a cylinder, and the other resin-affected zone surfaces are covered and joined with a corrosion-resistant material such as stainless steel. The present invention relates to a lining cylinder and a method for manufacturing the cylinder.

[0002]

2. Description of the Related Art High-performance plastics, so-called engineering plastics, are often those in which resin is filled with glass fiber or carbon as a filler, or a compound having a halogen group such as chlorine or bromine is added as a flame retardant. Injection molding machines are widely used to mold such plastics as final products, and the injection molding machines remelt the plastics that have already been pelletized by the kneading extruder and press them into the mold. It has the function of being injection-filled and molded into a molded product. The re-melting and high-pressure filling process of the plastics is mainly performed in the cylinder of the injection molding machine, but as described above, the plastic raw material contains components that are highly abrasive and corrosive (fillers and additives). ) Is included, the cylinder may be worn and corroded by this plastic material, shortening its life. For this reason, a means for lining a wear-resistant and corrosion-resistant alloy on the inner surface of the cylinder of the injection molding machine is provided, and the centrifugal casting method has been used for a long time as a method therefor. However, since it was difficult to form a lining layer with sufficiently high performance by the centrifugal casting method, recently, a powder sintering method in which a high performance alloy is lined by a hot isostatic press has come into wide use. There is.

However, in the above-mentioned centrifugal casting method and powder sintering method, the inner surface of the cylinder is mainly lined, and it is difficult to line all the resin contact parts such as the cylinder end surface, the hopper port, and the vent port at the same time. . Therefore, when abrasion resistance and corrosion resistance are required for the resin contact part,
A method of lining the inner surface of the cylinder with a wear-resistant and corrosion-resistant alloy and applying electroplating, chemical plating, or vapor deposition thin film coating to necessary or all resin contact parts after completion of machining is adopted. In rare cases, stainless steel, which is excellent in corrosion resistance, is used as a cylinder base material, and a wear-resistant / corrosion-resistant alloy is lined on the inner surface of the cylinder to secure the corrosion resistance of the resin-contacting portion.

[0004]

However, the durability of the plating and vapor deposition thin film coating applied to the hopper port and vent port is not sufficient, and it is consumed by abrasion from the filler and corroded by the additive. It is feared that it will be peeled off and become a contaminant in the resin. Furthermore, although the end surface on the cylinder nozzle side is not the resin contact portion directly, it is a sealing surface that receives the injection pressure, so a corrosive atmosphere is created and corrodes like other resin contact portions, causing a contaminant.

Further, when stainless steel is used as the cylinder base material, there is a problem that the material used is restricted. Specifically, when martensitic stainless steel is used, there is a risk that the lining layer will crack due to transformation stress during the cooling process after lining the cylinder inner surface.
As stainless steel, it is necessary to use expensive austenitic stainless steel or precipitation hardening stainless steel. Moreover, since these materials are difficult to machine, the machining cost becomes high. Further, since the boundary between the lining layer and the base material appears clearly at the hopper mouth, there is also a problem that this boundary is subjected to abrasive wear from the filler, which deteriorates the stability of the resin pellet feed. The present invention has been made in view of the above circumstances, in which a corrosion-resistant and wear-resistant lining layer is formed on the inner surface of a cylinder, while a resin-affected portion such as a cylinder end surface, a hopper port, and a vent port is coated and bonded with a food-resistant material. The present invention provides a long-life cylinder having excellent wear resistance and corrosion resistance, and a manufacturing method thereof.

[0006]

That is, in the lining cylinder for an injection molding machine of the present invention, a corrosion-resistant and wear-resistant lining layer is formed on the inner surface of the cylinder, and the resin-affected portion of the cylinder other than the inner surface, It is characterized in that the food materials are covered and joined. A second aspect of the invention is characterized in that the resin-affected zone to which the food material is coated and joined is at one or more locations of the cylinder end face, the hopper port, and the vent port. The third invention is characterized in that the food material is made of one or both of austenitic stainless steel and precipitation hardening stainless steel. Furthermore, in the method of manufacturing a lining cylinder for an injection molding machine according to the fourth aspect of the present invention, the food-resistant material is placed in close contact with the required resin-affected surface of the cylinder,
The corrosion resistant and wear resistant material is coated on the inner surface of the cylinder by the hot isostatic pressing method, and the corrosion resistant material is diffusion bonded to the surface of the resin-affected portion.

The material for the lining layer in the present invention is selected in consideration of corrosion resistance and wear resistance, but the type of the material is not limited to a particular one.
Further, the manufacturing method thereof is not particularly limited, and a centrifugal casting method, a hot isostatic pressing method or the like is appropriately selected.
Further, as the resin-affected zone referred to in the present invention, all the resin-contacted portions are applicable, and further, although not a direct resin-contacted portion,
It includes a portion such as a cylinder end surface that is subject to corrosion due to the influence of resin. The coating and joining of the corrosion resistant material to the resin-affected zone is not necessarily required to be performed for all the resin-affected zones, and for example, the coating and joining is performed only at a desired portion where durability is particularly required. The other resin-affected zones may be plated as in the conventional case.

A fixed product is used as the above-mentioned food material, and stainless steel having excellent corrosion resistance is desirable as the material. Among them, as shown in the third invention, austenitic stainless steel (particularly preferably SUS304) is used. And SUS316L stainless steel) and precipitation hardening stainless steel (particularly preferably SUS630 stainless steel) are more desirable. This is because martensitic stainless steel may cause cracking due to transformation stress, as in the case of using it as a cylinder base material. Further, the method of coating and joining the corrosion resistant material is not particularly limited, and a welding method, a brazing method, or the like can be adopted. However, in view of the joining strength, workability, and economical efficiency, it is shown in the fourth invention. It is most desirable to use the diffusion bonding method.

In the fourth invention, the hot isostatic pressure is preferably set at a heating temperature of 950 to 1200 ° C., more preferably at a heating temperature of 1000 to 1150 ° C. This is to suppress the decrease in the strength of the cylinder base material, to secure the bonding strength, and to bring the lining material characteristics into the optimum state. Further, in the fourth invention, as the resin-affected part for coating and joining the food resistant material, one or more positions of the cylinder end face, the hopper port and the vent port can be exemplified as in the second invention. It is preferable to use austenitic stainless steel or precipitation hardening stainless steel.

[0010]

In other words, according to the cylinder for an injection molding machine of the present invention, the inner surface of the cylinder is protected from corrosion and wear by the corrosion-resistant and wear-resistant lining layer, and the resin-affected zone is reliably corroded by the food material which is a fixed product. Is prevented. And, unlike the conventional plating and the like, the corrosion resistant material has excellent durability because it is bonded to the resin-affected zone as a fixed product, and partial peeling due to corrosion or wear does not occur, and therefore, It also does not cause contamination. Also, by covering and joining the above-mentioned resistant material to the hopper mouth,
Wear at the hopper mouth is prevented, and problems with unstable feed are eliminated. Further, the joining of the cylinder end surface prevents the corrosion of the sealing surface, and eliminates problems such as molded product burn and resin leakage. Also, it is not necessary to use a special material for the cylinder base material, and the cylinder for an injection molding machine having the most economical corrosion resistance and abrasion resistance can be obtained.

Further, according to the method for manufacturing a cylinder for an injection molding machine of the present invention, since the food materials are diffusion-bonded by the heating at the time of forming the lining layer, it is not necessary to separately perform the operation of bonding the food materials. Work efficiency is greatly improved and manufacturing cost is reduced. In addition, in the obtained cylinder, the inner surface has excellent corrosion resistance and wear resistance due to the lining layer formed by hot hydrostatic pressure, while on the other hand, the food material, which is a standard product, is not affected by the resin-affected part of the cylinder. It is firmly bonded and has a corrosion resistant coating with excellent durability.

[0012]

EXAMPLE An example of the lining cylinder for an injection molding machine of the present invention will be described below with reference to FIG. The cylindrical cylinder 1 uses SCM440 alloy steel as a cylinder base material, and one end thereof serves as the nozzle side end portion 2, while the cylindrical portion has a vent hole 3 and a hopper port 4 formed in a round hole shape. ing. The vent port 3 and the hopper port 4 are opened perpendicularly to the cylinder axis. However, in the present invention, in addition to this, the vent port 3 and the hopper port 4 are inclined at an angle as used in a vertical injection molding machine. It goes without saying that the present invention is also applied to those having an opening. And the cylinder 1
The inner surface of the is lined with a corrosion-resistant and wear-resistant alloy 5 in which a hard carbide is dispersed in a Ni-based Cr-B-Si alloy, and the lower inner peripheral walls of the vent port 3 and the hopper port 4 are similarly subjected to the above-mentioned corrosion resistance. Abrasive alloy 5 is lined.

Further, on the end face of the nozzle side end portion 2, the SU
A ring-shaped food material 6 made of S316L austenitic stainless steel is joined by diffusion joining at the contact surface with the cylinder 1. Also, from the upper part of the vent port 3 and the hopper port 4 to the central part, the same stainless steel cylindrical food materials 7 and 8 are fitted, and the outer peripheral wall of the vent material 3 and the hopper port 4 are diffusion-bonded. It is joined to the inner wall of the. The inner peripheral surfaces of the food materials 7, 8 are flush with the inner peripheral surface of the lower corrosion-resistant and wear-resistant alloy 5. According to this lining cylinder, a conventional material can be used as it is as the cylinder base material, and the inner surface of the cylinder, the cylinder end, the vent port, and the hopper port are coated with excellent corrosion resistance and wear resistance. Further, since the cylinder end, the vent port, and the hopper port are covered with stainless steel, which is a regular product, there is no partial peeling and the durability is excellent.

Next, an embodiment of a method of manufacturing the above lining cylinder will be described. First, as shown in FIG. 2, the nozzle 1 has an end portion 2 and a vent hole 3 which have substantially the same shape as the cylinder 1.
A cylinder rough material 1a having a and a hopper mouth hole 4a is prepared. Next, as a corrosion-resistant and wear-resistant material for lining the inner surface of the cylinder by hot isostatic pressure, Ni-based C
A powder alloy is prepared in which r, Si, and B are alloy elements, and hard carbide and necessary additives are mixed. Further, the nozzle side end portion 2 of the cylinder rough material 1a, the vent hole 3a
A blind lid 9 and blind stoppers 10 and 11 made of SUS316L austenitic stainless steel are prepared as the food materials to be placed in the hopper mouth hole 4a.

The blind lid 9 is made of a thick disc.
A hole through which a metal pipe 13 for hot hydrostatic pressure, which will be described later, penetrates is formed in the center, and a circular hole-shaped recess 9a having the same diameter as the hollow part of the cylinder rough material 1 is formed in the center part. Also,
The blind plug 10 and the blind plug 11 have a cylindrical shape that fits into the vent hole 3a and the hopper hole 4a, respectively.
At its tip, a vent hole 3a and a hopper hole 4a are provided.
The cylindrical projections 10a and 11a having a small diameter are formed so that a predetermined gap is formed with the inner peripheral wall surface of the. The blind lid 9 described above is applied to the end portion 2 of the cylinder rough material 1a with the recess 9a side facing inward, the peripheral edge of the contact portion with the cylinder rough material 1a is welded and fixed, and the blind plug 10 and the blind plug 11 are Cylindrical projection 10a,
The blind plug 10 and the blind plug 1 are fitted into the vent hole 3a and the hopper hole 4a so that 11a is on the lower side.
The corners of the outer peripheral wall of No. 1 and the outer wall of the cylinder of the cylinder rough material 1a are circumferentially welded.

On the other end side of the cylinder rough material 1a,
A ring-plate-shaped metal blind cover 12 on the hopper side is fixed by welding, and a metal pipe 13 for canning, which is a core, is passed through the center holes of the metal blind cover 12 on the hopper side and the blind cover 9 without any gap. The metal pipe 13 is welded and fixed to the blind lid 9 and the hopper-side metal blind lid 12. Next, the pipe 14 is penetrated from the outside of the blind lid 9 to the inside of the cylinder rough material 1, and the tip thereof is attached to the outer peripheral wall of the metal tube 13 and the cylinder rough material 1.
Face the space between the inner peripheral walls of a. Through the pipe 14, the powder alloy 15 prepared previously is supplied into the cylinder rough material 1a from the outside. The powder alloy 15 is filled in the space between the outer peripheral wall of the metal tube 13 and the inner peripheral wall of the cylinder rough material 1a, and the same applies to the outer peripheral spaces of the cylindrical protrusions 10a and 11a and the recess 9a of the blind lid 9. To be filled. Powder alloy 1
After filling 5, the inside of the cylinder rough material 1a is evacuated through the pipe 14, and then the pipe 14 is hermetically welded.

The cylinder rough material 1 assembled as described above is subjected to hot isostatic pressing at a heating temperature of 1000 ° C. and a pressure of about 100 MPa, and the alloy powder 15 is integrated by a sintering reaction. A corrosion- and wear-resistant lining layer is formed on the inner surface of 1a. On the other hand, by the heating at this time, the blind lid 9, the blind plug 10, and the blind plug 11 are firmly diffusion-bonded to the contact surface with the cylinder rough material 1a. The pressure-fired joint, the inner surface of the cylinder rough material 1a, the metal pipe 13 for canning is scraped off, leaving the corrosion-resistant and wear-resistant alloy lining layer of a predetermined thickness, and the blind lid 9, blind plug 10 and blind plug 11 are machined. After processing, the blind plug 10 and the blind plug 11 are perforated to finish the cylinder end surface 2, the vent port 3, and the hopper port 4 while leaving the stainless steel as shown in FIG. In the above lining cylinder, the lining layer is formed on the inner peripheral surface of the blind lid 9 and the lower portion of the vent port 3 and the hopper port 4 by the recess 9a and the columnar protrusions 10a and 11a. The boundary between the and the lining layer becomes smooth, and the abrasion at the boundary is prevented as much as possible. Then, a test piece including a diffusion bonding surface was cut out from the lining cylinder of FIG. 1 obtained by the above method, and a tensile test was performed. The result is 0.2% proof stress: 27.4kgf / mm ² Tensile strength: 60.7kgf / m
m ² Elongation: 33.4% Drawing: 70.5%. However, the breaking point of the test piece was on the stainless steel side, not on the joint interface, and it was confirmed that a sufficiently high joint strength was obtained on the joint interface.

[0018]

As described above, according to the lining cylinder for an injection molding machine of the present invention, excellent corrosion resistance and wear resistance is obtained not only on the inner surface of the cylinder but also on the end surface on the nozzle side and the resin-affected areas such as the hopper port and the vent port. Since a protective coating is obtained and these coatings have excellent durability, corrosion wear on the inner surface of the cylinder and the end surface of the hopper can be reduced, and the life limit can be extended due to burns of the molded product and unstable weight. Furthermore, it can be used stably even for strongly corrosive resins such as fluororesins and bromine-containing resins such as flame retardants. Even in a high-pressure injection molding machine whose injection pressure exceeds 200 MPa, corrosion of the cylinder nozzle side end surface which is the injection pressure sealing surface is effectively prevented. Furthermore, according to the method for manufacturing a lining cylinder of the present invention, it becomes possible to efficiently provide a corrosion- and wear-resistant coating having excellent durability on the resin-affected zone.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a lining cylinder according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a state of a rough material before being treated with a hot isostatic press in the manufacturing method of the embodiment.

[Explanation of symbols]

1 Cylinder 2 Nozzle Side End 3 Vent Port 4 Hopper Port 5 Corrosion-Resistant and Wear-Resistant Alloy 6 Material Resistant 7 Material Resistant 8 Material Resistant 9 Blind Cap 10 Blind Plug 11 Blind Plug 15 Powder Alloy

Claims (4)

[Claims] 1. An injection molding machine characterized in that a corrosion- and wear-resistant lining layer is formed on the inner surface of a cylinder, and a resin-affected portion of the cylinder other than the inner surface is covered and bonded with a food material. Lining cylinder 2. The resin-affected zone to which the food-resistant material is covered and joined,
The lining cylinder for an injection molding machine according to claim 1, wherein the cylinder end surface, the hopper port, and the vent port are provided at one or more locations. 3. The lining cylinder for an injection molding machine according to claim 1, wherein the corrosion resistant material is made of one or both of austenitic stainless steel and precipitation hardening stainless steel. 4. A corrosion resistant and abrasion resistant material is lined on the inner surface of the cylinder by a hot isostatic pressing method so that the corrosion resistant and abrasion resistant material is lined on the inner surface of the cylinder. A method for manufacturing a lining cylinder for an injection molding machine, characterized by performing diffusion bonding to the surface of the resin-affected zone.