JPS61154756A - Production of multi-hole cylinder for plastic molding machine - Google Patents

Abstract

PURPOSE:To obtain economically a defectless multi-hole cylinder made of a bimetal by providing a vacant hole having the same central axis as the central axis of a rough material for a cylinder barrel and a vacant hole which is eccentric and communicates with said vacant hole to said rough material, setting a core within the axis of eccentricity, pouring a molten alloy into each vacant hole and rotating the blank material for the barrel at a high speed. CONSTITUTION:The two vacant holes 12, 12a as mentioned above are provided to the blank material 11 for the cylinder barrel and the core 13 having the diameter smaller than the diameter of the hole 12a having a center in the position off the central axis 17 of the material 11 is set concentrically at the central axis of said material A blind plate 14 is attached to the bottom end of the material 11 and a top cap 15 having a pouring part 16 to the top end. The material 11 in this state is heated to 1,050-1,200 deg.C in a non-oxidative atmosphere and thereafter the self-fluxing Ni alloy consisting of the prescribed compsn. is poured 16 into the hole 12. The molten alloy is immediately cooled to solidify while the material 11 is rotated at a high speed around the axis 17 by which the rough material for the multi-pore cylinder formed with the desposited alloy layer 5 is obtd. The plate 14 and the cap 15 of the rough material are thereafter removed and the intended multi-pore cylinder for a plastic molding machine is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates primarily to a method for manufacturing a porous cylinder used in a plastic extrusion molding machine.

[Conventional technology]

The cylinders for extrusion molding machines are subject to wear and corrosion due to the synthetic resin. For example, when molding reinforced plastics or resin, hard materials such as gas lRm may cause wear and tear.
When molding flame-retardant plastics, halogens cause corrosion.

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

As cylinders for plastic extrusion molding machines, there are two types of cylinders in practical use: a single-screw cylinder with one screw hole and a twin-screw cylinder with two screw holes.

Single-shaft bimetallic cylinders can be easily manufactured by centrifugal casting of wear- or corrosion-resistant alloys;
Since a twin-screw cylinder has two screw holes, it is not possible to apply alloy to the inner wall surface of the hole by centrifugal casting.

For this reason, the twin-shaft cylinders are manufactured with a lot of innovation.

FIG. 2 shows an example of a conventional biaxial cylinder in which a bimetallic liner 2 is inserted into a steel biaxial cylinder body l cut out from a solid steel bar and having parallel perforations. The liner 2 is made by welding together two liners obtained by cutting out a part of a uniaxial bimetallic liner so as to have a figure-eight cross section. However, this cylinder is made of a very large amount of machined metal, which makes it less 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 3 shows another conventional bimetallic cylinder 3 formed by cutting out a part of a single-shaft bimetallic cylinder 3 in its axial direction and joining the remaining notched cylinders to each other by welding. This is an example of a cylinder.

This cylinder 3 compensates for the drawbacks of the liner insertion type cylinder described above. However, this requires a process of cutting out parts of the two uniaxial cylinders and a process of welding them together, resulting in a heavy economic burden during manufacturing. In addition, when welding and joining, the adhered alloy layer is eroded and destroyed, making it impossible to weld and join the alloy layer and its vicinity.The cylinder corrodes due to the intrusion of resin and generated gas into the unwelded joint surfaces. Therefore, there are also functional problems.

As a solution to these problems, patent application No. 1773
No. 2 introduces a bimetallic porous cylinder in which a wear-resistant or corrosion-resistant adherent alloy layer 5 is formed on the inner wall surface of a screw hole formed in a cylinder body 4 made of an integral steel material, as shown in Fig. 4. .

FIG. 5 is a cross-sectional view illustrating a method for manufacturing a bimetallic porous cylinder proposed in Japanese Patent Application No. 17732/1985, in which the beaked structure shown in FIG. 5 is heated in a non-oxidizing atmosphere furnace;
Next, in the space 9 formed between the cylinder body 4 and a pair of cores 6 and 6 set in one screw hole, a perforated cylinder made of a corrosion-resistant alloy or a bimetal made by this manufacturing method is placed.
Although it is less economical and functional than those shown in FIG. Furthermore, as the cylinder becomes longer, it is necessary to increase the number of feeders in order to ensure the health of the layer used. This means a lack of economy due to an increase in the amount of expensive alloys used and an increase in the number of processing steps.

[Problem that the invention seeks to solve]

As mentioned above, single-axis bimetal cylinders have traditionally been manufactured mainly by centrifugal casting, but it has been thought that multi-hole cylinders cannot be manufactured by centrifugal casting due to the basic principles of centrifugal casting. . In fact, there are no known reports on the manufacture of perforated cylinders by centrifugal casting.

Figure 6 shows the results when a two-wheeled cylinder was manufactured using the same centrifugal casting method as that used for a single-shaft cylinder. It is not possible to cover the entire inner wall of the screw hole.

The present invention aims to eliminate the above-mentioned conventional drawbacks and to provide a manufacturing method that can economically produce an intact bimetallic porous cylinder by centrifugal casting.

[Means for solving problems]

Figure 1 is a cross-sectional view for explaining the manufacturing method of the cylinder of the present invention, where (a) is a cross section perpendicular to the cylinder axis, and (1)) is a cross section taken along line A-A in figure (a). FIG.

As shown in FIG. 1, two holes 12.12a are provided in the cylinder body material 11. One of the two holes 12 is provided so as to be concentric with the center axis 17 of the cylinder body material 11, and the other hole 12m is provided so as to be concentric with the center axis 17 of the cylinder body material 11. It is provided eccentrically so as to have its center at a position nine off the shaft 17, and communicates with the hole at the central axis position. The distance from the center axis 17 of this cylinder body rough material 11 is 1 tK.
A core 13 with a smaller diameter than the hole 12& is placed in the hole 12& having a center so that it is concentric with the hole 12a. Attach the top lid 15 with the inlet 16.

The cylinder body rough material 11 formed as described above is heated to 1050 to 1200°C in a non-oxidizing atmosphere.

Next, the Si 2.5 to 4.0 To
%Co5-40%, Cr5-10%, Mn0.2-2
Consisting of L remainder Ni and unavoidably present impurities,
A predetermined amount of molten Ni-based self-fluxing alloy, which has corrosion resistance and wear resistance, is injected from the injection port 16 into the central cavity 12, and immediately casted at high speed around the central axis 17 of the cylinder body rough material 11 on a centrifugal casting machine. The material is cooled and solidified while being rotated to obtain a porous cylinder rough material on which the deposited alloy layer 5 is formed.

The blind lid 14 and jacket 15 of this raw material are removed by machining, and the core 13f is also removed. Next, the outer diameter of the cylinder body rough material 11 is machined so that the midpoint between the holes 12 and 12m becomes the central axis.After this, predetermined machining such as hole machining and end face machining is performed by a normal machining method. Then, a bimetallic multi-shaft cylinder with a cross section as shown in Figure 4 is completed (Figure 4 shows a bi-shaft cylinder).
Effect] A predetermined amount of the molten alloy injected into the center hole 12 is pumped into the center hole 12 by centrifugal force caused by high-speed rotation around the center shaft 17 of the cylinder body rough material 11. Holes 12m and core 1 are coated with uniform thickness on the circumferential surface and are eccentric by 1.
3, the deposited alloy layer 5 is formed and solidified.

The porous cylinder rough material with the deposited alloy layer 5 formed in the two holes 12, 12a of the cylinder body is machined as described above in the subsequent steps to be finished into a porous cylinder.

[Example 1] After processing the outer diameter of the steel material so that the outer diameter of the cylinder body rough material having a length of 25011 mm becomes 160 φ, a pair of holes with a distance between windows of 34 mm and an inner diameter of 42 mm each were formed in the manner described above. and one of the holes located away from the central axis of the cylinder body material has a 35 mm diameter hole.
A steel core of φ was attached to the top and bottom, and upper and lower plates made of steel plates were attached to the upper and lower ends, and the core was heated to 1100° C. in an electric resistance furnace. This was melted in a high frequency melting furnace to give Si2.7% by weight.

Mn1. OS, Cr10.0%, Co15.0%
, B3.2%% A self-fluxing alloy with the balance mainly consisting of N1
The molten metal was injected at 350℃, immediately transferred to a centrifugal casting machine, and the rotation speed was set so that the gravity multiplier was 90 at the 38φ position of the hole provided concentrically with the center axis of the cylinder body rough material. was adhered to the inner wall of the hole in the cylinder body material by centrifugal force.

When the centrifugal casting machine started rotating, forced cooling was performed from the outer surface of the cylinder body rough material using mist, and the outer surface temperature reached 70.
When the temperature reached 0 to 750°C, forced cooling and rotation were stopped to allow gradual cooling.

After cooling, the upper and lower plates were removed, and the outer diameter of the cylinder body material was machined to 110φ so that the pair of holes were axially symmetrical.Then, the alloy coating was removed to the specified size, and final finishing was performed. As a result, the cylinder was honed to a diameter of 38φ, and a healthy bimetallic biaxial cylinder with no defects was obtained.

[Example 2] In the same manner as in Example 1, an alloy was applied to a steel material having a cylinder body size of 250φ and a length of 500t so that the distance between the windows was 55m and a pair of holes with an inner diameter of 64φ had a thickness of 60mm. , Example 1
Using the same method as above, the inner diameter of each screw hole was finished to 60φ, and we were able to obtain a bimetallic two-shaft cylinder that was defect-free and sound over its entire length.

〔Effect of the invention〕

The present invention has great industrial value because it is configured as described above, and a bimetallic porous cylinder that is sound and has excellent corrosion resistance and wear resistance can be manufactured economically.

Although the present invention has been described with reference to two pores, other pore shapes may be used.

In addition, a wear-resistant or corrosion-resistant alloy may be used instead of the alloy described in the examples, and in this case, the heating temperature of the cylinder body material, the alloy injection temperature, etc. may be changed depending on the characteristics of the alloy. Of course.

[Brief explanation of the drawing]

Fig. 1 is a sectional view explaining the process of manufacturing a perforated cylinder according to the present invention, Figs. 2, 3, and 4 are sectional views of a conventional bimetal biaxial cylinder, and Fig. 5 is the same. A cross-sectional diagram illustrating the manufacturing process of a conventional bimetallic twin-shaft cylinder,
FIG. 6 is a cross-sectional view illustrating the corrosion resistance and the deposition of wear-resistant alloy when attempting to manufacture a bimetallic twin-shaft cylinder by the usual centrifugal casting method. 5: Adhering alloy layer, lll Niji Linda body material 12: Hole in central axis 12a: Eccentric hole, 13: Core,
14: Blind lid, 15: Top lid, 16: Inlet, 1
7: Central Axis Patent Attorney Takashi Honma Procedural Amendment (Voluntary) This month ↓, 1985

Claims (1)

[Claims] 1 at the center axis of the cylinder body material made of cylindrical steel material.
holes are provided in the axial direction, and 1 hole is provided at an eccentric position.
one or more holes are provided in the axial direction in communication with the hole in the central shaft, a core is installed in the eccentric hole concentrically with the hole, and the cylinder body material is One end is closed with a blind lid and the other end is closed with a lid having an injection port, which is heated, and a predetermined amount of molten alloy is injected into the hole in the central shaft through the injection port, and the centrifugal casting machine Attach it to the machine and rotate it at high speed.
After forming a deposited alloy layer in each hole and cooling it, the lids at both ends of the cylinder body material and the core in the eccentric hole are removed, and then the center axis is set at the midpoint of each hole. 1. A method for manufacturing a porous cylinder for a plastic molding machine, which comprises processing the outer diameter of a cylinder body blank material, and further performing other predetermined processing such as drilling each hole in which the deposited alloy layer is formed.