JP2000308926A - Manufacture of heating cylinder for molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacture method of a heating cylinder for a molding machine. SOLUTION: In a manufacture method of a heating cylinder with a coating layer 2 of resistance alloy formed in a cylinder inner surface, nests 3, 4 formed out of or coated with a material, to which a hot static pressure water press method can be applied in the same condition to the coating material, are manufactured, a hole is worked in a position serving as a hopper port 5 of the heating cylinder and/(or) a position serving as a tip end part, the nests 3, 4 are inserted in adhesion, a resistance alloy layer is formed by the hot static pressure water press method in a position in an internal periphery of the heating cylinder and serving as the hopper port and/(or) position serving as the tip end part, so as to position the nest in a location necessary for resistance in the hopper port and/(or) the tip end part, the hopper port and/(or) the tip end part is applied with cutting work.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a heating cylinder for a molding machine. In recent years, plastics have been diversified in use, and there is a tendency that various additives and reinforcing materials such as glass fibers are mixed and injected or extruded at high pressure. Therefore, the inner surface of a heating cylinder for a molding machine such as an extrusion molding machine or an injection molding machine is easily susceptible to abrasion due to these glass fibers and the like. Furthermore, when molding a resin that generates chlorine gas or other corrosive gas during kneading, the heating cylinder is also required to have corrosion resistance. Under these circumstances, in order to provide wear resistance and corrosion resistance to the molding machine heating cylinder, a heating cylinder having a structure in which an inner surface of the cylinder base material is coated with an alloy layer having wear resistance and corrosion resistance has been used. ing.

A heating cylinder for a molding machine has a hopper port for resin injection. This hopper mouth
Since it is pierced after the formation of the coating layer on the inner surface of the heating cylinder,
No abrasion resistant alloy layer is formed on the inner surface. For this reason, when injecting resin, there is a problem that the hopper opening is subject to wear or corrosion by the resin. If abrasion or corrosion occurs, poor biting or the like occurs, and stable molding cannot be performed. In addition, since the front end of the heating cylinder is also post-processed in the same manner, a portion that is easily worn or corroded remains. When the corrosive gas generated when the resin melts flows into the sealing surface of the heating cylinder and the nozzle that has been brought into mechanical contact, the base material (generally alloy steel) is exposed on the sealing surface of the heating cylinder. And the base material portion is corroded at an early stage because of the fact that it has high corrosion resistance and the like as compared with the resistant alloy coated on the inner surface. As a result, the resin leaks from the combined sealing surface, or the screwing pressure and injection pressure are locally applied to the protruding coating layer, causing cracks in the inner coating layer and damage to the heating cylinder. Leads to. The present invention relates to a technique for abrasion and corrosion resistance of a hopper port and a cylinder tip in a heating cylinder used in such an injection molding machine or an extrusion molding machine.

[0003]

2. Description of the Related Art As prior art, the following conventional examples I and I
There are I and III. (1) Conventional Example I (JP-A-4-147906, JP-A-4-147822, JP-B-3-4601,
JP-A-6-114914, JP-A-7-25671
In this conventional example I, a pilot hole is drilled in a main body serving as a hopper opening by machining, a core smaller than the pilot hole is loaded into the hole, powder is filled into a formed gap, and hot static is performed. A wear and corrosion resistant alloy layer is formed by a hydraulic pressing method. When processing the hopper opening, the front surface of the hopper or the whole is covered with an alloy layer. However, the conventional example I has the following problem. When the powder is filled, the gap between the pilot hole and the core shrinks due to the diffusion bonding (solidification) of the powder, so that the heating cylinder bends. If the coating layer on the inner surface of the cylinder is made of a brittle material, cracking will occur if bending is forced. As a countermeasure against bending, a solid core to be inserted into the hopper is replaced with a hollow core (Japanese Patent Application Laid-Open No. 4-147906,
No. 601), there is a method of reducing the bending by applying pressure from the inner surface of the core, but in this case, there is a problem that the core shape is complicated and the core processing cost is increased.

(2) Conventional Example II (Japanese Patent Laid-Open No. 6-114914) In this conventional example II, a pilot hole is drilled in a hopper opening, a separately formed hopper-shaped alloy steel or the like is inserted, and bolting is performed. Alternatively, they are fixed by shrink fitting or the like. However, the conventional example II has the following problem. Since the nest is separately formed, the processing cost of the nest becomes a cost increase factor. The shape of the nest may be complicated, and since it is a high-hardness member requiring abrasion resistance, the machining cost is high due to polishing, electric discharge machining, and the like. In the case of a complicated hopper opening, it is difficult to fit the hole into the main body hole. Since there is a gap between the nest and the cylinder body, there is a possibility that resin powder enters. Then, when the resin is changed to a resin of a different color, there is a problem that the previous color is mixed in the next molded product. If the pilot hole of the cylinder body is enlarged by the thickness of the nest, the strength is reduced due to the decrease in the cross-sectional area. When a bolt hole or the like is formed for fixing, a cross-sectional area is reduced, and a stress concentration portion is generated, resulting in a decrease in strength.

(3) Conventional example III (JP-A-7-256718)
This conventional example III relates to the corrosion resistance treatment of the tip of the heating cylinder. The contents and problems are as follows. It is conceivable to apply a sealing material to the sealing surface at the tip of the cylinder. However, since the molding temperature is about 400 ° C. or higher, sealing materials such as rubber and plastic may be deteriorated by heat. In addition, it is difficult to use because there is a possibility of being mixed as a foreign substance into a molded product. Although plating may be partially applied, plating may be difficult due to the shape of the tip of the heating cylinder. In addition, adhesion may also be a problem due to the compatibility between the material coated on the inner diameter portion and the plating material. The plating film cannot be said to have sufficient corrosion resistance against various corrosive gases generated from the resin, and the film thickness is too thin to take sufficient measures against corrosion of the heating cylinder end face. The inner surface is coated with a material different from the base material in order to impart corrosion resistance to strong corrosive gas generated when the resin melts and wear resistance to fillers such as glass and carbon contained in the resin. The alloy is mainly Ni
A base alloy, a Co base alloy, or a material obtained by adding a hard carbide or the like to them is used. There is also a method of joining an iron-based material such as stainless steel that has corrosion resistance to the cylinder end face, but this is because corrosion resistance is much lower than that of a Ni-based alloy or Co-based alloy that has corrosion resistance and wear resistance coated on the inner surface. The measures are not enough. The strong corrosive gas that corrodes the cylinder end surface is the same as the gas that corrodes the inner surface of the cylinder. Not be. In the method of forming a coating layer at the tip of the heating cylinder by diffusion bonding of powder and filling the powder with hot isostatic pressing, large deformation occurs due to shrinkage of the powder inserted in the gap. The lid and the like provided for sealing may be damaged.

[0006]

SUMMARY OF THE INVENTION In view of the foregoing, the present invention provides wear resistance and / or corrosion resistance to a hopper port of a heating cylinder for a molding machine and the tip of the cylinder, and the heating cylinder has a bend. It is an object of the present invention to provide a method of manufacturing a heating cylinder that has advantages such as no generation, easy processing, low cost, and no reduction in strength.

[0007]

According to a first aspect of the present invention, there is provided a method of manufacturing a heating cylinder for a molding machine, comprising the steps of: (a) manufacturing a heating cylinder having a coating layer made of a resistant alloy on an inner surface of the cylinder; A nest made or covered with a resistant alloy to which a hot isostatic pressing method can be applied under the same conditions as the covering layer is prepared, and (c) the nested hole is located at a position to be a hopper port and / or a tip portion of a heating cylinder. A hole is machined, and the nest is inserted into the prepared hole in close contact with the hole, and (d) a position serving as an inner periphery of the heating cylinder and a hopper port and / or
A coating layer made of the above-mentioned resistant alloy is formed by hot isostatic pressing at a position to be the tip, and (e) the nested resistant alloy portion is located at the hopper port and / or at a site where resistance is required at the tip. So that the hopper port and / or the tip is cut. The method for manufacturing a heating cylinder for a molding machine according to claim 2 is a method for manufacturing a heating cylinder in which a coating layer made of a resistant alloy is formed on the inner surface of the cylinder. (Or) drill a pilot hole in the position to be the tip,
(c) forming a resistant alloy layer in the prepared hole by a welding method or a thermal spraying method, (d) forming a coating layer made of a resistant alloy by a hot isostatic pressing method on the inner periphery of the heating cylinder, (e) The hopper port and / or the tip portion is cut so that the resistance alloy layer is located at a site where the hopper port and / or the tip portion requires resistance. In the present invention, the term “resistant alloy” is a concept including all alloys having only wear resistance, alloys having only corrosion resistance, and alloys having wear and corrosion resistance. In this specification, a hot isostatic press may be hereinafter referred to as HIP.

According to the first aspect of the present invention, since the coating layer on the inner surface of the cylinder and the nest are simultaneously HIPed, the process can be simplified and the cost can be reduced. Then, the nest is inserted into the pilot hole and HIP is performed together with the coating material on the inner surface of the cylinder.However, unlike the method of filling the gap provided in the hopper opening with powder, the cylinder does not bend, and the cylinder base metal and the coating layer are formed. Can be firmly diffusion bonded. According to the second aspect of the present invention, before the HIP is applied to the cylinder body serving as the base material of the heating cylinder, a resistance alloy layer is formed directly on the hopper port and at a location that becomes the cylinder tip by a welding method, and then the inner coating layer is formed. By sealing and HIPing after filling the powder to be formed, corrosion resistance and wear resistance can be imparted to the tip and the hopper. Moreover,
Unlike the method of filling the gap provided in the hopper opening with powder, the cylinder does not bend.

[0009]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram of a method for manufacturing a heating cylinder according to an embodiment of the present invention. FIG. 2 is an explanatory view of the nest 3 for the hopper mouth (FIGS. Ad) and the nest 4 for the tip end (FIG. E). 3A is a plan view of the state where the nest 3 is inserted into the cylinder body, and FIG. 3B is a sectional view taken along line BB of FIG. 4A is a plan view showing a state where a hole is formed in a hopper opening, and FIG. 4B is a cross-sectional view taken along a line BB of FIG. FIG. 5 is a cross-sectional view of the heating cylinder manufactured by the manufacturing method of claim 1. FIG. 6 is an explanatory view of a step of forming a resistant alloy in the manufacturing method according to the second aspect of the present invention. FIG.
FIG. 4 is an explanatory view of a cylinder inner surface coating forming step in the manufacturing method. FIG. 8 is a sectional view of a working cylinder manufactured by the manufacturing method of the second aspect.

I. Embodiment of the Invention of Claim 1 In FIG. 1, reference numeral 1 denotes a cylinder body of a heating cylinder. Reference numeral 2 denotes a coating layer formed of a resistant alloy formed on the inner periphery of the cylinder body 1. Reference numeral 2a denotes a powder for forming the coating layer 2, for example, having the following composition. (Specific composition) Si (silicon): 0.5 to 3% by weight B (boron): 0.5 to 3% by weight Cr (chromium): 1 to 40% by weight Remainder: Ni (nickel) and / or Co (cobalt) 3 is a hopper Nesting to form a resistant coating on the mouth,
Reference numeral 4 denotes a nest for forming a resistant coating layer at the tip of the cylinder, and serves as a lid for sealing the capsule. As shown in FIGS. 2A to 2D, the nest 3 is a pin 31 without a flange made of a resistant alloy (FIG. 2A), and a pin 31 with a flange made of a resistant alloy. (B), a pin body 30 with a flange coated with a resistant alloy (FIG. C), a pin body 30 without a flange coated with a resistant alloy 31 (d), and the like. be able to. The insert 4 is obtained by applying a coating 41 of a resistant alloy to a thick disk 40.

Next, the manufacturing method of the present embodiment will be described. (1) First, a method for forming a hopper port will be described. A nest 3 coated with a resistant alloy 31 capable of diffusion bonding under the same conditions as the coating material applied to the inner surface of the cylinder 3 ((C) in FIG. 2)
To (d)) or a nest 3 of a single molded body of a resistant alloy (FIG. 2 (a) to (b)). The application of the resistant alloy coating 31 of the nest 3 is not limited to the welding method, but also includes the thermal spraying method, the HIP method,
It may be performed by a sintering method, a casting method, or the like. A pilot hole 6 is drilled in a part of the cylinder body 1 which will eventually become the hopper port 5, a nest 3 is inserted into the pilot hole 6, and fixedly sealed by welding or the like (FIGS. 1 and 3). After assembling other parts, the coating layer 2
Is filled and powdered to form HIP. The resistant alloy coating portion 31 and the coating layer 2 of the cylinder body 1 and the insert 3 are firmly diffusion bonded by heat and pressure by HIP. When a hole is formed in the hopper port so that the resistant alloy-coated portion 31 of the nest 3 is located at a position where the abrasion resistance and corrosion resistance of the hopper port 5 are required (line X in FIGS. 1 and 3), the necessary portion of the hopper port is formed. A heating cylinder with abrasion and / or corrosion resistance can be manufactured (FIG. 5).

(2) The method of forming the tip of the cylinder is substantially the same. First, the nest 4 (FIG. 2 (e)) in which the lid 40 is coated 41 with a resistant alloy material capable of diffusion bonding under the same conditions as the inner surface coating layer 2 of the cylinder body 1 by welding or the like, or The nest 4 of the single molded body 41 is created (FIG. 2 (f)).
). The application of the resistant alloy covering portion 41 of the insert 4 may be performed not only by the overlay welding method but also by a thermal spraying method, a HIP method, a combustion method, a casting method, or the like. This nest 4 is installed in a portion that will eventually become the cylinder tip of the cylinder body 1 and fixedly sealed by welding or the like (FIG. 1). After assembling other components, the inner peripheral coating layer 2 is formed. After filling and sealing the powder 2a, HIP is performed. The resistant alloy coating portion 41 and the coating layer 2 of the cylinder body 1 and the insert 4 are firmly diffusion bonded by heat and pressure by HIP. When cutting is performed so that the resistant alloy-coated portion 41 of the nest 4 is located at a position where corrosion resistance is required at the tip (line y in FIG. 1), wear resistance and / or
A heating cylinder with corrosion resistance can be manufactured (FIG. 5).

The advantages of the above manufacturing method are as follows. A material that can be HIPed under the same conditions as the material to be coated on the inner surface of the cylinder is nested as a coating material, and is diffusion-bonded to the hopper port and the cylinder end surface as a single molded body of the material. Diffusion bonding can be performed. Unlike the method of filling the gap provided for covering the hopper port 5 with powder, the cylinder body 1
There is no fear of bending. The manufacturing cost can be reduced as compared with the conventional nesting method. Resin powder does not accumulate in gaps as compared with the conventional nesting method. There is no reduction in strength due to a decrease in the cross-sectional area of the screw hole and the hopper as compared with the conventional method of performing bottle tightening by the nesting method. A material having the same abrasion resistance and corrosion resistance as the material coated on the inner periphery of the cylinder is provided at the cylinder tip 7 or the hopper port 5.
Can be installed on It can be coated with a material having much higher corrosion resistance and wear resistance than stainless steel.

II FIG. 6 to FIG.
It will be described based on. Preliminary holes 11 and 12 are formed in advance at positions to be the hopper port 5 of the cylinder body 1 and the cylinder tip 7 before HIP (FIG. 6). Resistive alloy layers 13 and 14 are formed in the pilot holes 11 and 12 by welding or thermal spraying. The prepared hole 11 may be a hole having the same size as the resistant alloy layer 13 to be formed (FIG. A).
A larger hole (FIG. B) may be used. After assembling a lid, a core, and the like into the cylinder body 1 and filling the inner surface thereof with the powder 2a that forms the coating layer 2, the lids 15, 1
Then, the capsule is formed by sealing with 6 or the like (FIG. 7). By subjecting the capsule to HIP processing, the cylinder body 1 and
The resistant alloy layers 13 and 14 and the inner coating layer 2 constructed at the same time are strongly diffusion-bonded simultaneously by the temperature and pressure of the HIP. HIPed capsules are machined into target shape (Fig. 8
(Indicated by lines X and Y) of the cylinder body 1
A heating cylinder having corrosion resistance and abrasion resistance is formed at the tip 7 and the hopper port 5 (FIG. 8).

The advantages of the above manufacturing method are as follows. Unlike the method of filling the gap provided for covering the hopper port 5 with powder, there is no fear that the cylinder body is bent due to contraction of the gap. The manufacturing cost can be reduced as compared with the conventional nesting method. Resin powder does not accumulate in gaps as compared with the conventional nesting method. There is no reduction in strength due to a decrease in the cross-sectional area of the screw hole and the hopper, as compared with the conventional nesting method of bolting. When the wear-resistant or corrosion-resistant material is coated on the tip portion 7 and the hopper port 5 of the heating cylinder having the coating layer formed on the inner surface in advance by welding or the like, the coated alloy layer may be damaged. There is no fear of this since the welding is performed directly on the cylinder body 1 by the overlay welding method. A coating may be formed on the cylinder body 1 before the canning by a thermal spraying method, a lid, a core and the like may be assembled, filled with powder, sealed, and HIPed. In this case, the coating material is preferably a material that can be diffusion-bonded under the same HIP conditions as the coating material. The overlay is a material that can be welded or sprayed with the body,
It can be manufactured as long as it can be HIPed under the same conditions as the coating material on the inner surface of the cylinder. Materials with much higher corrosion resistance and abrasion resistance than stainless steel etc. can be constructed.

[0016]

According to the first aspect of the present invention, since the coating layer on the inner surface of the cylinder and the insert are simultaneously HIPed, the process can be simplified and the cost can be reduced. The nest is inserted into the pilot hole and HIP is performed together with the coating material on the inner surface of the cylinder.At this time, since there is no gap for filling the powder in the hopper opening, the cylinder does not bend, and the base metal and the coating layer are firmly bonded. Can be diffusion bonded. According to the invention of claim 2, before the HIP is applied to the cylinder main body serving as the base material of the heating cylinder, a resistant alloy layer is formed by a direct welding method at a location to be the hopper port and the tip of the cylinder, and then the inner coating layer is formed. By filling and forming a HIP after filling with the powder that forms the powder, corrosion resistance and wear resistance can be imparted to the tip and the hopper. Moreover, unlike the method of filling the gap in the hopper opening with powder, the cylinder does not bend.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a method for manufacturing a heating cylinder according to an embodiment of the present invention.

FIG. 2 is an explanatory view of a nest 3 for the hopper opening (FIGS. Ad) and a nest 4 for opening the tip end (FIGS. F).

FIG. 3A is a plan view of a state in which a nest is inserted into a cylinder body, and FIG. 3B is a cross-sectional view taken along line BB of FIG. 3A.

4A is a plan view showing a state where a hole is formed in a hopper opening, and FIG. 4B is a sectional view taken along line BB of FIG. 4A.

FIG. 5 is a sectional view of a heating cylinder manufactured by the manufacturing method of the first embodiment.

FIG. 6 is an explanatory view of a step of forming a resistant alloy in the manufacturing method according to the second aspect of the present invention.

FIG. 7 is an explanatory diagram of a heating cylinder manufacturing method according to an embodiment of the manufacturing method.

FIG. 8 is a sectional view of a working cylinder manufactured by the manufacturing method of the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder main body 2 Coating layer 3 Nesting 4 Nesting 5 Hopper port 13 Resistance alloy layer 14 Resistance alloy layer

Claims (2)

[Claims] 1. A method for manufacturing a heating cylinder, comprising: (a) a coating layer made of a resistant alloy formed on the inner surface of a cylinder; and (b) a resistant alloy to which a hot isostatic pressing method can be applied under the same conditions as the coating layer. Prepare a nest made or coated in the above, (c) processing a pilot hole at a position to be a hopper mouth and / or a tip part of a heating cylinder, and insert the nest closely into the pilot hole, (d) forming a coating layer made of the resistant alloy by hot isostatic pressing on the inner periphery of the heating cylinder and a position serving as a hopper port and / or a position serving as a tip, and (e) the nesting resistance. (F) cutting the hopper port and / or the tip so that the alloy part is located at a position where the hopper port and / or the tip requires resistance; Method. (2) A method for manufacturing a heating cylinder in which a coating layer made of a resistant alloy is formed on the inner surface of a cylinder, wherein (b) a position which becomes a hopper opening and / or a position which becomes a tip portion of the heating cylinder. The prepared hole is processed, (c) a resistant alloy layer is formed in the prepared hole by a welding method or a thermal spraying method, and (d) a coating layer made of a resistant alloy is formed on the inner periphery of the heating cylinder by a hot isostatic pressing method. And (f) cutting the hopper port and / or tip so that the resistant alloy layer is located at a site where resistance is required at the hopper port and / or tip (f). A method for manufacturing a heating cylinder for a molding machine.