JPS60181208A - Manufacture of multi-shaft cylinder for plastic molding machine - Google Patents

Abstract

PURPOSE:To simplify the manufacturing stages by sintering and bonding an alloy filled into screw holes in a cylinder barrel along the insides of the holes with a hot hydrostatic press. CONSTITUTION:A pair of parallel and adjacent screw holes are pierced in a cylinder barrel 4 made of a monolithic steel material, and hollow cores 10, 10a are concentrically placed in the holes. A wear or corrosion resistant alloy is filled into the gap 9 between the cores 10, 10a and the barrel 4, and it is sintered with a hot hydrostatic press. An alloy layer 5 of a uniform thickness is bonded to the barrel 4 to obtain a rough body for a multi-shaft cylinder. By this method, the manufacturing stages are simplified, and the corrosion or wear resistance is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for manufacturing a multi-shaft cylinder mainly used in a plastic extrusion molding machine.

[Prior art]

Cylinders for plastic extrusion molding machines are subject to wear and corrosion due to synthetic resin. For example, when molding reinforced plastics, hard materials such as glass fibers cause wear and tear, and l
Molding of it-Ma plastics is subject to corrosive effects due to free halogens.

Conventionally, nitrided cylinders have been used for cylinders for plastic extrusion molding machines, but they do not have sufficient wear resistance or corrosion resistance, and cannot withstand the molding of reinforced plastics or flame-retardant plastics. Ta. Therefore, in the molding of such plastics, a bimetallic cylinder is used, in which the inner wall surface of the cylinder is coated with a wear-resistant or corrosion-resistant alloy by centrifugal casting.

As cylinders for plastic extrusion molding machines, there are two types of cylinders in practical use: an axle cylinder with one screw hole and a two-shaft cylinder with two screw holes. Single-shaft bimetallic cylinders can be easily manufactured using wear-resistant or corrosion-resistant alloys by centrifugal casting, but bimetallic cylinders have two screw holes, so centrifugal casting can produce alloys inside the screw holes. It cannot be attached to the wall. For this reason, two-wheel cylinders are manufactured using various techniques.

FIG. 1 shows two examples of conventional biaxial cylinders in which a bimetallic liner (2) is inserted into a steel biaxial cylinder body (1) cut out from a solid steel bar and having parallel perforations. This liner (2) is made by welding together two liners obtained by cutting out a portion of a uniaxial bimetallic liner so as to have a figure-eight cross section. However, this cylinder requires a very large amount of machining and is not economical, and the outer circumferential surface of the liner (2) does not necessarily come into close contact with the inner circumferential surface of the cylinder body (1), so the heat transfer effect is poor. There are some disadvantages. Figure 2 is an example of another conventional biaxial cylinder formed by cutting out a part of the bimetallic cylinder of the axle in the axial direction and joining two notched cylinders together by welding. be. This cylinder (3) compensates for the drawbacks of the liner insertion type cylinder described above. However, since it requires a process of cutting out parts of the two axle cylinders and a process of welding them together, the economical burden during manufacturing is heavy. Furthermore, when welding and joining, the adhered alloy layer is eroded and destroyed, making it impossible to weld and join the alloy layer and its surroundings, and the resin and generated gas entering the unwelded joint surfaces can damage the cylinder. There is also a functional problem because it corrodes.

To solve these problems, JP-A-57-3-131532 discloses that a wear-resistant or corrosion-resistant material is installed on the inner wall surface of the screw hole formed in the cylinder body (4) made of an integral steel material, as shown in Fig. 3. A bimetallic multi-shaft cylinder coated with an alloy layer (5) is introduced.

Figures 4a and 4b are diagrams illustrating an example of a method for manufacturing a bimetallic multi-shaft cylinder disclosed in Japanese Patent Application Laid-Open No. 57-131532, in which the structure shown in the figure is placed in a non-oxidizing atmosphere furnace. The cylinder body (4) and a pair of cores (6) are then heated.
1. Into the space (9) formed between
8a) and fills the space (9) to obtain a cylinder rough material. The bimetallic multi-shaft cylinder manufactured by this manufacturing method is superior in terms of economy and functionality to the cylinders shown in Figs. ) will need to be increased. This means an increase in the amount of expensive alloy used and an increase in the number of processing steps.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a multi-axis cylinder for a plastic molding machine, which can reduce the amount of expensive alloy used and the number of processing steps.

[Structure of the invention]

The method for manufacturing a multi-axis cylinder for a plastic molding machine of the present invention is to provide wear-resistant or This process includes the steps of filling a corrosion-resistant alloy, molding it using a hot isostatic press machine (hereinafter abbreviated as HIP machine), and sintering and depositing it. The multi-axis cylinder rough material obtained by the HIP device is processed by a normal processing method to have a screw hole of a predetermined size.

In the HIP device, the space between the cylinder body and the core is filled with alloy powder.
The alloy layer is sintered and adhered to the inner wall surface of the screw hole formed in the cylinder body by heating and pressurizing it to around kg/Ca ~ 1400 kg/cA, so a strong alloy layer with a constant thickness can be formed. As a result, the thickness of the alloy layer can be made thinner than conventional ones, less powder alloy is used, and fewer steps are required for finishing the alloy layer.

5- Next, the present invention will be explained in detail by way of embodiments and with reference to the drawings.

〔Example〕

Figures 5a and 5b show the alloy layer (5) of the cylinder of the present invention.
Fig. 5a shows a cross section perpendicular to the cylinder axis, and Fig. 5b shows the VB-VB in Fig. 5a.
A cross section is shown. As shown in Figures 5a and 5b, first, the respective axes of a pair of holes are formed in a cylinder body (4) having a pair of parallel and adjacent screw holes in an integral steel bar. Holes (14) and (1
4a) with hollow core 001. (10a) is installed, the lower plate (12) is joined to the end face of the cylinder body, and the gap (
9), for example, B2-4. Si 2.5~1
0%, 005~40%, Cr 5~10%, Mn
A Ni-based self-melting alloy powder (11) having corrosion resistance and wear resistance, consisting of 2 to 2.0% O, the balance being Ni and unavoidably present impurities, is filled, and then the cylinder body (4
) was joined to the end of the upper plate (13), deaerated and sealed, and heated to 980°C with a HIP device, 1100kg/cJ.
It was sintered under pressure and attached to the cylinder body (4).

Next, this structure was cooled to room temperature at a cooling rate of 20 to 100° C./hr, and then a multiaxial cylinder rough material having a sound and uniformly thick alloy layer deposited thereon was obtained.

The lower plate (12) and upper plate (13) of this rough material were removed by machining, and holes were machined using normal processing methods until the specified dimensions were reached, completing the bimetal biaxial cylinder as shown in Figure 3. did. The bimetallic multi-shaft cylinder manufactured in this way exhibits sufficient corrosion resistance and wear resistance, and can be manufactured economically as it uses a small amount of alloy and requires few cutting processes. The value is extremely large.

In the embodiments of the present invention, the outer periphery of the cylinder body is circular and there are two inner holes, but other porous shapes are also possible. Alternatively, a corrosion-resistant alloy may be used, and in that case, it is natural that the processing conditions such as pressure and temperature will change depending on the characteristics of the alloy.

17= [Effects of the Invention] According to the present invention, the space between the inner wall surface of the screw hole of the cylinder body and the hollow core to be inserted can be made small, so a small amount of alloy is required, and a bimetal multi-shaft can be manufactured with less machining. This has the effect of allowing cylinders to be manufactured efficiently through a simple process.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a two-shaft cylinder using a conventional bimetal liner assembly system, Figure 2 is a cross-sectional view of a two-shaft cylinder using a conventional bimetal joining system, and Figure 3 is a cross-sectional view of a bimetallic liner assembly method.
No. 1532 and the cross-sectional view of the bimetallic cylinder according to the method of the present invention, FIG.
4b is a cross-sectional view for explaining the manufacturing process of the bimetallic cylinder for a twin-screw extruder according to Publication No. 2.
Figure a is a longitudinal sectional view taken along the line IVB-TVB, Figure 5a is a cross sectional view for explaining the manufacturing process of a biaxial cylinder for a plastic molding machine according to the method of the present invention, and Figure 5b is a vertical sectional view taken along the line IVB-TVB.
It is a longitudinal cross-sectional view taken along the line VB-VB in Figure a. 8- (■) Biaxial cylinder body (2) Niliner (3): High metal cylinder (4) Niji cylinder body (5): Alloy layer f6), (6a): Core (7): Lower plate (8) : Upper plate (8a) : Alloy injection hole (9) : Space (10), (10a) : Hollow core (11) : Alloy powder (]2) : Lower plate (13) :
Upper plate (14), (14a): Hole 9-

Claims (1)

[Claims] 1. It is characterized by including the step of filling the inner wall surface of the screw hole formed in the cylinder body made of one piece of material with a wear-resistant or corrosion-resistant alloy, and forming and sintering it using a hot isostatic press machine. A manufacturing method for multi-axis cylinders for plastic molding machines.