JP2937802B2 - Die for granulation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a granulating die used in combination with an underwater cutting device or an aerial cutting device in a plastics granulator.

[0002]

2. Description of the Related Art FIG. 3 is a longitudinal sectional view showing the shape of a conventional granulating die in a plastic granulator, FIG. 4 is a longitudinal sectional view of a cutting device provided in the granulator, and FIG. 5) is a longitudinal sectional view showing a relationship between a conventional granulating die and a cutter blade, and FIG. 5 (B) is a plan view showing a configuration of the cutter blade.

[0003] As shown in Figs. 3 and 4,
A circulation box 106 circulating warm water (or air) at 50 to 80 ° C. is provided.
Die 10 having annular die hardened layer surface 103 on the surface
2 is comprised. This die 102 is a die holder 1
01 is connected and held by bolts or the like.

[0004] A large number of φ2.
A nozzle 104 of 3 to 3.5 mm is provided, and the molten resin passes through the die holder 101 and the inside of the die, and is extruded from the nozzle 104 into the circulation box 106.

[0005] A plurality of cutter blades 112 are arranged so as to contact the die hardened layer surface 103. The plurality of cutter blades 112 rotate at a high speed (600 to 1200 rpm).
m) cutter holder 111 at the shaft end of possible cutter shaft 110
It is fixed using.

That is, the cutter blade 112 is provided on the nozzle 104 provided on the die hardened layer surface 103 by the cutter shaft 11.
In this configuration, the molten resin extruded from the nozzle 104 into the circulation box 106 by passing through the rotation of 0 is cut.

In such an apparatus, the cutter blade 112 wears over time (0.01 to 0.03 mm /
Sun), so the cutter blade 112 and the die hardened layer surface 1 during operation
There is a gap between the first and the third. In this case, granulation is impossible, and in order to prevent the granulation, a pressing force is constantly applied to the hydraulic cylinder built in the cutting device 109 during the operation, so that the clearance between the cutter blade 112 and the die hardened layer surface 103 is increased. Is configured to always disappear. This type of cutter is called an automatic pressing cutter.

Further, at the center of the surface of the die 102 facing the inside of the circulation box 106, bolts for connecting the die 102, a gasket 107 for maintaining the airtightness of the gap between the bolt holes, and a retainer for holding the gasket 107 are provided. This is a structure having a plate 108 and the like. Also, cutter blade 1
Since the die hardened layer is worn together with the wear of 12, the annular hardened layer portion is somewhat protruded. for that reason,
A depression 105 is formed.

In the granulating apparatus having the above-described configuration, as shown in FIG. 3, the molten resin that has passed through the die holder 101 flows into the die 102, and the nozzle 1 on the surface 103 of the die hardened layer.
04 is pushed out to the circulation box 106.

At the same time, as shown in FIG. 4, the cutter blade 1 continuously rotating at a high speed on the surface 103 of the die hardened layer.
By 12, the extruded molten resin is cut in the warm water circulating in the circulation box 106. This cut resin is called a pellet.

The pellets are usually in the form of a column or a stone having a diameter of about 3 to 5 mm.
３０30 tons.

[0012]

However, in the above-mentioned granulating apparatus, a large amount of pellets produced (granulated) sometimes enter the gap between the cutter blade and the hollow at the center of the die surface and remain as it is. Yes (Fig. 5 (A)
reference).

This residual pellet refuses the cutter shaft to advance. Further, as shown in FIG. 5, the pellets stuck in the gap between the hollow at the center of the die surface and the root of the cutter blade lose their escape and stay there.

The small lumps of the pellets are successively granulated, pressed by new pellets discharged from the nozzle, adhere to the pellets, and grow larger.

In this case, even if the automatic pressing mechanism works to make up for the wear (gap) of the cutter blade, the cutter blade is obstructed by the residual pellet soul and cannot move forward. At the same time, the circulation box is filled with the solidified molten resin. This is because cutting cannot be performed unless the cutter blade is in close contact with the surface of the die hardened layer, and the resin flows out of the die nozzle into the circulation box as if it were raging. As a result, the operation becomes an emergency stop. Some users perform production with an emergency stop at a rate of once / 8 hours. In worse cases, it takes a week to recover. In particular, in the case of a resin having a low viscosity or a low melting point, poor cutting frequently occurs due to a minute gap (gap) between the surface of the die hardened layer and the cutter blade, thereby deteriorating productivity.

In view of the above-mentioned problems, the present invention can prevent granules from remaining in the gap between the hollow at the center of the die surface and the root of the cutter blade during the granulation operation. It is intended to provide a die for use.

[0017]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention comprises a part of a side wall of a circulation box through which hot water or air is circulated, and a part of a surface facing the inside of the circulation box. The part is a ring-shaped hardened layer surface to which a plurality of blade-shaped cutter blades rotating at high speed around an axis are in close contact, and the hardened layer surface has a large number of discharging molten resin into the circulation box. In a granulating die of a granulating apparatus provided with a nozzle, a portion surrounded by the hardened layer surface is flush with the hardened layer surface.

In the granulating die configured as described above, a peripheral groove centering on the shaft is formed at a portion where the root of the cutter blade abuts.

[0019]

In the granulating die of the present invention configured as described above, the molten resin is discharged from a number of nozzles provided on the surface of the annular hardened layer into the circulation box in which hot water or the like circulates. The resin pellets are cut by a plurality of blade-shaped cutter blades rotating at a high speed around a shaft into resin pellets, which are sent to a predetermined position by a flow of warm water or the like in a circulation box and collected.

At this time, if there is a recess in a portion surrounded by the surface of the annular hardened layer, including a portion in which the vicinity of the root of the cutter blade is in close contact, the resin pellets enter the recess and remain, and the cutter is left. This has hindered the close contact between the blade and the surface of the hardened layer, resulting in poor cutting and inoperability.

However, in the present invention, since the depression is eliminated and the surface of the hardened layer is flush with the surface of the hardened layer, the hardened surface of the die and the cutter blade are always in close contact with each other, so that production failure and defective cutting do not occur.

Further, in the granulating die of the present invention, a circumferential groove centered on the axis is formed in a portion where the root of the cutter blade abuts. The displacement of the set position at the time of replacement due to the variation in assembly accuracy is absorbed, and the blade contact with the die hardened layer surface is always flush.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing a shape of an embodiment of a granulating die of the present invention in a plastics granulating apparatus.

The granulating die of this embodiment eliminates the depression in the central portion surrounded by the annular die hardened layer surface shown in FIG. 3, and is flush with the die hardened layer surface 3 as shown in FIG. It is the structure which did.

On the die hardened layer surface 3, several hundred pieces to 200 pieces
Zero nozzles 4 (φ2.3 to 3.5 mm) are provided, and the molten resin is pushed through the die holder 1 and the die 2 into the circulation box 6 from the nozzles 4. The circulation box 6 is filled with warm water circulating at 130 to 390 m ³ / h.

On the surface 3 of the hardened die layer, 16 to 2
The four blade-shaped cutter blades 7 are arranged so as to be in contact with each other. Such a cutter blade 7 is attached to an end face of a cutter holder 8. The cutter holder 8 is connected to the tip of a cutter shaft 9 capable of rotating at a high speed of 600 to 1200 rpm by an electric motor (not shown) with a bolt or the like. While hydraulic pressure is constantly applied to the cutter shaft 9,
Since the cutter blade 7 also generates a propulsive force (propeller effect) due to the rotation of the cutter shaft, the cutter blade 7 is constantly pressed against the die 2.

In such a granulating die of this embodiment,
Since there is no dent like the conventional die shown in FIG. 3,
After the granulation, the pellets stay and the cutter blade 7 is prevented from advancing toward the die 2, and the surface 3 of the hardened die layer and the cutter blade 7 are always in close contact with each other. As a result, non-production or poor cutting does not occur.

In the above-described apparatus for performing granulation in a state where the cutter blade 7 rotating at a high speed is constantly pressed against the surface 3 of the die hardened layer, the surface of the die hardened layer 3 and the cutter blade 7 are formed. Wear is inevitable, and it is necessary to replace the worn cutter blade with a new one.

In such replacement of the cutter blade, since the surface 3 of the hardened die layer to which the cutter blade 7 has adhered is reduced due to abrasion and a step is formed at the center of the die 2, the surface of the hardened dice layer is removed. It is difficult to match a new cutter blade with the production accuracy and the assembly accuracy of the cutter blade, since there is usually a variation.

FIG. 2 shows the relationship between the new blade and the surface of the die hardened layer at the time of replacement.

As shown in FIG. 2, when the setting position of the cutter blade is deviated due to the influence of the manufacturing accuracy and the assembling accuracy of the cutter blade, the cutter blade 7a is brought into close contact with the worn die hardened layer surface 3a. It turns out that granulation cannot be performed.

For this reason, in the present embodiment, a peripheral groove 5 centering on the axis of the cutter shaft 9 is formed in a portion of the die 2 where the root of the cutter blade 7 abuts.

Accordingly, the cutter blade 7 is set within the width of the circumferential groove 5.
The displacement of the set position due to the influence of the manufacturing accuracy and the assembly accuracy of the die can be absorbed, and the blade contact with the surface of the die hardened layer can always be flush (uniform) each time the cutter blade is replaced.

[0035]

Since the present invention is configured as described above, the following effects can be obtained.

According to the first aspect of the present invention, at least a part of the surface facing the inside of the circulation box forms part of the side wall of the circulation box through which hot water or air circulates.
An annular hardened layer surface to which a plurality of blade-like cutter blades rotating at a high speed around an axis are closely attached, and a number of nozzles for discharging molten resin into the circulation box are arranged on the hardened layer surface. The granulated dies are provided, and the portion surrounded by the hardened layer surface is made to be the same as the hardened layer surface, so that the hardened layer surface and the cutter blade are always in close contact during the granulation operation. And no production stoppage or defective cutting occurs.

[0037] In the invention described in claim 2, in the granulating die according to claim 1, a peripheral groove centering on the shaft is formed in a portion where the root of the cutter blade abuts, so that the die hardening. When the surface of the layer is reduced due to abrasion by the cutter blade, it is possible to prevent a problem caused by a step difference from the center of the die.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a shape of an embodiment of a granulating die of the present invention in a plastics granulating apparatus.

FIG. 2 is a diagram showing a relationship between a new blade and a die hardened layer surface at the time of replacement.

FIG. 3 is a longitudinal sectional view showing a shape of a conventional granulation die in a plastics granulator.

FIG. 4 is a longitudinal sectional view of a cutting device provided in the granulating device.

5A and 5B are diagrams for explaining a problem of a conventional granulating die, wherein FIG. 5A is a longitudinal sectional view showing a relationship between a conventional granulating die and a cutter blade, and FIG. FIG. 3 is a plan view showing a configuration.

[Explanation of symbols]

 Reference Signs List 1 die holder 2 dice 3 die hardened layer surface 3a worn die hardened layer surface 4 nozzle 5 circumferential groove 6 circulation box 7 cutter blade 7a new cutter blade 8 cutter holder 9 cutter shaft

Claims (2)

(57) [Claims] 1. A circulation box in which hot water or air is circulated
A part of the side wall of (6), and a part of the surface facing the inside of the circulation box is in close contact with a plurality of blade-shaped cutter blades (7) rotating at high speed around an axis. An annular hardened layer surface (3), on the hardened layer surface (3), a number of nozzles (4) for discharging the molten resin into the circulation box are provided, and a granulating die of a granulating device is provided. In the above, the portion surrounded by the hardened layer surface (3) is the hardened layer surface
A granulating die, which is flush with (3). 2. The granulating die according to claim 1, wherein a peripheral groove (5) centering on the shaft is formed at a portion where a root of the cutter blade (7) abuts. And a granulating die.