JP2001225359A - Nozzle for injection molding and method for injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that in an injection molding, a molten molding material, when pulled, is extended in the shape of a string and stuck to a sprue through a cold slug to cause stringing, when the string of the molding material is cut and held in a mold to make demolding difficult, the mold is dented, and when the string is not cut and a molding is not demolded easily, the molding is caught by the mold to make continuous molding and stable molding impossible to cause the deterioration of the quality of the molding. SOLUTION: The length of the land part of a nozzle attached to the tip of the cylinder of an injection molding machine is 5 mm or below, and the land part is expanded toward the inside of the nozzle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding nozzle in an injection molding machine which does not cause a defective phenomenon such as stringing, and an injection molding method using the injection molding nozzle.

[0002]

2. Description of the Related Art Conventionally, injection molding machines have been used for molding thermoplastic and thermosetting plastic molded articles due to their mass productivity. Such an injection molding machine generally includes a mold clamping section, an injection section, and the like, and the injection section is provided with a cylinder for kneading, measuring, and injecting a molding material.

FIG. 2 is a longitudinal sectional view of a nozzle of a conventional injection molding machine, taken along a longitudinal axis. As shown in the figure, the conventional injection molding machine includes a cylinder (not shown) having a band heater 113 for melting the molding material and adjusting the temperature of the nozzle 101. Also, in the figure, the weighing and suckback are completed, the nozzle 101 separates from the fixed-side mold 108 (a cylinder (not shown) including the nozzle 101 moves away from the fixed-side mold 108), and the fixed-side mold 108 is moved. When the mold is opened between the movable mold 108 and the movable mold (not shown), the sprue 106 is attached to the movable mold and moves in the direction of the arrow, and the sprue 106 is moved to the fixed mold 1.
08 when the sprue 106 moves away from the nozzle 101 (the sprue 106 moves away from the nozzle 101).

The nozzle 101 has an opening 102, and the opening 102 has a diameter of usually φ1.5 to φ3 mm.
Land part 10 having a length of about 10 mm.
Three. The land 103 has a taper 104
, And extends from the inside toward the outside toward the opening 102 of the nozzle 101.
The angle 109 of the taper 104 is usually 2 to 3 degrees. With such a taper 104, the cooled resin, that is, the cold slag 110 at the land 103 adheres to the sprue 106 at the end 112, and does not remain in the nozzle 101.
If such a cold slag 110
When the molding material is injected in the case of a direct gate mold, the cold slag 110 flows into the cavity and mixes with the molded product to deteriorate the accuracy and quality of the molded product if it remains in the first land portion 103. there is a possibility. 105
Reference numeral 107 denotes a molten molding material in the nozzle 101, and reference numeral 107 denotes a state of stringing attached to the sprue 106.

FIG. 2 shows a case in which a thermoplastic molding material is molded. A band heater 113 is provided in a cylinder having a nozzle 101. However, when a thermosetting molding material is used, the band heater 113 is used. Is unnecessary and can be omitted.

[0006]

In the conventional injection molding shown in FIG. 2, when a molding material in a molten (flowing) state is pulled, the molding material is extended in a thread shape. A state in which the thread-like material is attached to the sprue 106 via the cold slug 110 and pulled is referred to as a thread puller 107. When the stringing 107 occurs, if the thread of the pulled long molding material is cut and caught in the mold, the mold may be dented, or the molded article may be released from the mold without the thread breaking. If not, the molded product is sandwiched between the molds, so that continuous molding cannot be performed and stable molding cannot be performed, thereby causing a problem of deteriorating the quality of the molded product.

There are several methods for preventing such stringing from occurring.

First, a method for molding a thermoplastic molding material will be described. First, during injection molding, the tip of the nozzle 101 is kept in contact with the fixed side mold 108 all the time. Cool the tip side,
The molding material in the inside 111 of the tip of the nozzle 101 is
This is a method of cooling down from the opening 102 of the “01” considerably deeply.

In general molding, the nozzle is in contact with the mold at the time of injection holding pressure measurement, but after the injection holding pressure is finished, the nozzle is separated from the mold after measurement and suck back (the nozzle is attached). Moving the cylinder away from the mold). The reason for separating the nozzle from the mold is that, for example, when molding a thermoplastic molding material, the nozzle is temperature-controlled to a temperature at which the molding material melts (eg, 200 ° C. to 300 ° C.), whereas the mold is Since the temperature is much lower (for example, 40 ° C. to 120 ° C.), if it is kept in contact with the mold, the tip side of the nozzle becomes too cold, the temperature of the entire nozzle becomes unstable, and the molding material This is because the viscosity becomes unstable.

However, when stringing occurs, continuous molding cannot be performed.
It is necessary to keep the nozzle in contact with the fixed mold so that the tip of the nozzle is cooled so that it is too cold, so that the molding material contained in the tip of the nozzle is cooled to make it easier to cut.
Therefore, in such a method, although the yarn is cut, there is a problem that the accuracy of the molded product is deteriorated.

The second is a method which has the same purpose as the above-mentioned method, but sets a lower control temperature at the nozzle. However, in this method, since the temperature of the molding material in the whole inside of the nozzle is lowered, there is a problem that the transferability is reduced and the molding accuracy is reduced.

Another method is to adopt a large suck back. With suck back, after measuring the molding material,
The operation of forcibly moving the screw to the opposite side to the nozzle opening by a length of several mm (usually 2 to 3 mm). Thus, the cold slag at the land portion of the nozzle and the molten molding material deeper in the nozzle than the cold slag are separated, and the molten slag that has adhered to the cold slag by that much When the molding material is stretched and thinned, it is easy to cut.

However, in order to eliminate stringing, 5
mm, and sometimes 20 mm. When the suck back amount is increased, the cold slug can be removed from the nozzle land when the nozzle is separated from the mold, or when the mold is opened and the sprue moves to the movable mold and moves out of the fixed mold. However, at the time, the amount of air entering through the nozzle opening increases, causing the air to be trapped during injection, resulting in many appearance defects such as voids (bubbles) and silver. Will happen. In addition, in the case of a molding material that is easily oxidized, there is a problem that the molten molding material in the nozzle is oxidized by air entering from the nozzle opening, thereby causing appearance defects such as burns. Become.

[0014] Accordingly, an object of the present invention is to solve such problems in the prior art by stringing, voids, and the like.
An object of the present invention is to provide an injection molding nozzle capable of obtaining a molded product having excellent quality and accuracy without causing a defect phenomenon such as silver or burnt.

Another object of the present invention is to provide a molded article having excellent quality and precision by using the above-mentioned injection molding nozzle without causing stringing, defective phenomena such as voids, silver, and burns. To provide an injection molding method capable of obtaining the following.

[0016]

According to the present invention, in order to achieve the above-mentioned object, the length of a land portion of a nozzle attached to the tip of a cylinder of an injection molding machine is 5 mm. In the following, the land portion extends toward the inside of the nozzle.

Further, the injection molding nozzle of the present invention is characterized in that the angle at which the land extends toward the inside of the nozzle is 1 ° or more and 5 ° or less.

Furthermore, the injection molding nozzle of the present invention is characterized in that the nozzle is provided so as to extend along the longitudinal axis of the cylinder of the injection molding machine.

According to the injection molding method of the present invention, the length of the land portion of the nozzle attached to the tip of the cylinder of the injection molding machine is 5
mm or less, and the molding is performed using an injection molding machine provided with a nozzle whose land portion extends toward the inside of the nozzle.

Further, in the injection molding method of the present invention, the angle at which the land portion extends toward the inside of the nozzle is 1 ° or more and 5 ° or less.

Further, the injection molding method of the present invention is characterized in that the nozzle is provided so as to extend along a longitudinal axis of a cylinder of the injection molding machine.

Furthermore, the injection molding method of the present invention is characterized in that injection molding is performed using either a thermoplastic olefin-based or norbornene-based material as a molding material.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the injection molding nozzle according to the present invention, the length of the land portion of the nozzle is as short as 5 mm or less, and the land portion extends toward the inside of the nozzle. By using, the cold slag is removed from the land of the nozzle and remains on the nozzle side, and the molding material is cut off between the cold slag and the sprue. Since it is small and good, it hardly entraps air, it does not cause defects such as voids, silver, burns, etc., it can reduce the amount of cold slag, and the cold slag does not clog at the land part ,
Stable continuous molding becomes possible.

In the injection molding nozzle of the present invention, when the taper angle is 1 ° or more, when the nozzle is separated from the mold,
Or, when the mold is opened and the sprue sticks to the movable mold and moves, and the sprue moves in the direction away from the nozzle, cold slag comes off from the nozzle land and sticks to the sprue. No cold slag remains on the nozzle side. Since both the cold slag and the sprue are cold molding materials, there is an effect that the resin of the molding material is cut between the cold slag and the sprue, and defects such as stringing do not occur. In addition, since the suck-back amount is small, the air hardly gets caught, so that defects such as voids, silver, and burns do not occur.

Further, in the injection molding nozzle of the present invention, if the taper angle of the land portion toward the inside of the nozzle is 5 ° or less, the cold slag may cause
This has the effect of entering into the mold together with the reliably injected molten molding material and preventing clogging at the land portion, thereby enabling stable continuous molding.

Further, in the injection molding nozzle of the present invention, since the nozzle is provided so as to extend along the longitudinal axis of the injection molding machine, the injection molding can be performed smoothly, and the mold is opened and the sprue is opened. When moved with the mold,
The cold slag does not come off from the nozzle land and stick to the sprue, the cold slag remains securely on the nozzle side, and the molding material is cut between the cold slag and the sprue, causing stringing. Does not wake up.

In the injection molding method of the present invention, the length of the land portion of the nozzle attached to the tip of the cylinder of the injection molding machine is 5 mm or less, and the land portion extends toward the inside of the nozzle. Since the molding is performed using the attached injection molding machine, the cold slag remains on the nozzle side, and the molding material is cut off between the cold slag and the sprue, so that stringing does not occur.
Accordingly, the suck-back amount is small and good, and almost no air is entrapped, so that defects such as voids, silver, and burns do not occur. In addition, since the length of the land portion is short, the amount of cold slag can be reduced, and when the molten slag is injected together with the molding material, the cold slag may be clogged at the land portion having a taper angle. There is also the effect of not being present, and stable molding is possible.

In the injection molding method of the present invention, when the taper angle is 1 ° or more, the sprue moves from the nozzle when the nozzle is separated from the mold or when the mold is opened and the sprue is attached to the movable mold. When moving away, the cold slag is securely removed from the nozzle lands and remains on the nozzle without being attached to the sprue. Since both the cold slag and the sprue are cold molding materials, there is an effect that the resin of the molding material is cut between the cold slag and the sprue, and defects such as stringing do not occur.
In addition, since the amount of suckback is small, the air hardly gets caught, and the void,
There are no defects such as silver and burns.

Further, in the injection molding method of the present invention,
The taper angle toward the inside of the land nozzle is 5
゜ If it is below, the cold slag will enter the mold together with the molten molding material that is reliably injected at the time of injection, and will have the effect of not clogging at the land.
Stable continuous molding becomes possible.

Further, in the injection molding method of the present invention, since the nozzle to be used is provided so as to extend along the longitudinal axis of the injection molding machine, the injection molding is performed smoothly, and the mold is opened. When the sprue moves with the mold, the cold slag is removed from the nozzle land and does not stick to the sprue, the cold slag remains securely on the nozzle side, and the cold slag and sprue The molding material is cut in between and no stringing occurs.

Furthermore, in the injection molding method of the present invention, since injection molding is performed using a thermoplastic olefin-based or norbornene-based molding material as a plastic molding material, stringing, voids, silver, burnt, etc. Even in the case of thermoplastic olefin or norbornene-based molding materials, which have the characteristic that many defects occur, by using the above-described injection molding method, defects such as stringing, voids, silver, and burns are generated. Without this, a high-precision, high-quality molded product can be obtained.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments of the present invention with reference to the accompanying drawings.

(Embodiment 1) An embodiment which best shows the features of the injection molding nozzle of the present invention will be described in detail with reference to FIG. Although the description of the present embodiment is made for the case where a thermoplastic molding material is injection-molded, the present invention can be similarly applied to the case of a thermosetting molding material.

FIG. 1 shows the vicinity of an injection molding nozzle according to the present invention. As shown, an injection molding machine comprises a nozzle 1 for injecting a molten molding material, and A cylinder (not shown) having a band heater 13 for adjustment is provided. In the same figure, as in FIG. 2, the weighing and suckback are completed, and the nozzle 1 separates from the fixed mold 8 (a cylinder including the nozzle 1 (not shown)).
Move away from the fixed mold 8) and the fixed mold 8
The mold is opened between the movable mold (not shown) and the sprue 6 is attached to the movable mold, moves in the direction of the arrow, and the sprue 6 comes out of the fixed mold 8. .

The members having the same functions as those in FIG. 2 are denoted by the same reference numerals. FIG. 1 differs from FIG. 2 in that the length of the land portion 3 is shortened, and the taper 4 of the land portion 3 has a taper angle 9, and the nozzle 1
(The direction is opposite to the direction of the taper 104 in FIG. 2).

Since the land 3 has a taper angle 9 and is open toward the inside of the nozzle 1, as shown in FIG. It will remain within 1.

The stringing occurs when the molten molding material 5 adhered to the cold slag 10 is stretched. That is, in other words, stringing occurs between the cold slag 10 and the molten molding material 5.

Therefore, as in the conventional example shown in FIG.
When the taper 104 has a shape that opens toward the opening 102 of the nozzle 101, the cold slug 110
Will adhere to the sprue 106 and the molten molding material 105 adhered to the cold slag 110
However, when the cylinder (not shown) including the nozzle 101 is retracted, or when the mold opens between the fixed mold and the movable mold, the sprue 106 sticks to the movable mold and moves in a direction away from the nozzle 101. When it is pulled, it takes the form of a stringer 107 that is pulled and stretched. Therefore, a large suck back was used to eliminate the stringing 107. However, a large amount of air entered the inside of the tip portion 111 of the nozzle 101 as described above,
Entrapment of the air at the time of injection causes defects such as voids, silver, and burns in the molded product.

However, if the cold slag 10 is left in the nozzle 1 as in the present invention, since both the cold slag 10 and the sprue 6 are cold molding materials, the cold slag 10 and the sprue 6 are separated from each other. No stringing occurs between the cold slug 10 and the sprue 6, and the tip of the sprue 6 has a shape without stringing like the end 12.

Further, the amount of suck-back is slightly (0.5 to
2 mm) is sufficient, and the volume of the portion inside the tip end portion 11 of the nozzle 1 is small, so that the amount of air is small and defects such as voids, silver, and burns do not occur.

Further, since the length of the land portion 3 is as short as 5 mm or less, the amount of the cold slag 10 can be reduced, and when the molten slag 10 is injected together with the molten molding material 5, the cold slag 10 is tapered. There is an effect that the land portion 3 having 9 has no clogging, and stable continuous molding can be performed. If the length of the land 3 is 5
If it exceeds mm, depending on the contact time between the nozzle 1 and the fixed mold 8 and the temperature control conditions of the nozzle 1 and the fixed mold 8, the cold slug 10 is formed at the land 3 having the taper angle 9. The possibility of clogging comes out.

Here, the present inventors have examined the taper angle 9 in detail, and found that the taper angle 9 should be in the range of 1 ° or more and 5 ° or less, that is, in the range of 1 ° to 5 °.
It has been found that the conditions are more desirable such that continuous stable molding can be performed without occurrence of defects such as voids, silver, and burns.

If the taper angle 9 of the land 3 is 1 ° or more, when the cylinder (not shown) including the nozzle 1 is retracted, or when the mold is opened between the fixed mold 8 and the movable mold, the sprue is opened. When the cylinder 6 moves in the direction away from the nozzle 1 by sticking to the movable side mold, the cold slug 10 is removed from the land 3 of the nozzle 1 and sticks to the sprue 6 without being said to be cold slug. 10 surely remains on the land portion 3 of the nozzle 1. Also, since both the cold slag 10 and the land 3 are cold molding materials,
It is cut off between the cold slag 10 and the land portion 3, so that a defect such as stringing does not occur. Further, since stringing does not occur, there is no need to use a large suckback amount, so that defects such as voids, silver, and burns do not occur.

Conversely, if the taper angle 9 is smaller than 1 °,
Although it depends on the temperature conditions of the nozzle 1, the cold slag 10
Is removed from the land 3 of the nozzle 1 and sticks to the sprue 6, whereby the molten molding material 5 attached to the cold slag 10 is pulled and stretched, and stringing may occur.

If the taper angle 9 of the land 3 is not more than 5 °, the cold slag 10 surely enters the mold together with the molten molding material 5 to be injected at the time of injection. There is no clogging of the cold slag 10 at this point. Therefore, continuous stable molding can be performed.

Conversely, if the taper angle 9 exceeds 5 °, depending on the temperature conditions at the nozzle 1 and the like, a problem such as the clogging of the cold slag 10 at the land portion 3 occurs and an excessive pressure during the injection occurs. , And stable continuous molding may not be performed.

During the injection, when the cold slag 10 enters the mold together with the molten molding material 5 to be injected, the cold slag 10 enters the cavity and adversely affects the precision and quality of the molded product. Although the possibility may be a concern, if there is no direct gate structure where the sprue is directly connected to the cavity, there is no problem. No problem. It is even more preferable to take a slightly larger sprue lock or to make a discarded tab at the branch point of the runner.

The injection molding method of the present invention can be applied to any thermoplastic and thermosetting molding materials.
It is particularly useful for thermoplastic olefin or norbornene molding materials.

The thermoplastic olefin-based or norbornene-based molding material has toughness due to its molecular structure, and has properties such that it is hard to be cut even in the form of a thin thread. In particular, stringing is likely to occur.
Similarly, a thermosetting olefin-based or norbornene-based molding material hardly absorbs moisture, but has a property of absorbing air. Therefore, there is a property that defects such as voids and silver are more likely to occur as compared with general molding materials. In addition, it has a tertiary carbon structure due to its molecular structure, and has a property that it is easily oxidized (burn easily occurs). Therefore, it is particularly effective to apply the injection molding method of the present invention, and it is possible to obtain a molded article having excellent precision and quality free from defects such as stringing, voids and silver.

The thermoplastic olefin-based or norbornene-based molding materials include, specifically, "Zonex" (trade name) of Zeon Corporation, "Apel" (trade name) of Mitsui Chemicals, Inc. "Arton" (trade name) of Japan Synthetic Rubber Co., Ltd. and the like. Further, other polyethylene, polypropylene, and the like also fall into this category, and there is an effect that defects such as stringing, voids, silver, and burns do not occur, and stable continuous molding can be further achieved.

As described above, in the injection molding nozzle of the present invention, a nozzle is used in which the length of the land portion of the nozzle is 5 mm or less and the land portion extends toward the inside of the nozzle. This has the effect that defects such as stringing, voids, silver, and burns do not occur.

Further, since the land portion of the nozzle is widened toward the inside of the nozzle, the sprue moves when the nozzle is separated from the mold or when the mold is opened and the sprue is attached to the movable mold. When moving away from the nozzle, the cold slag comes off the land of the nozzle,
There is nothing to say that it sticks to the sprue and cold slag remains on the nozzle side. Also, cold slag and sprue are both cold molding materials,
Between the cold slag and the sprue, there is an effect that the molding material is divided, and no stringing occurs. Accordingly, the suck-back amount is small and good, and almost no air is entrapped, so that defects such as voids, silver, and burns do not occur.

Also, since the length of the land portion is short, the amount of cold slag can be reduced. When the cold slag and the molten molding material are injected together, the cold slag has a land having a taper angle. There is an effect of preventing clogging at the part, and stable continuous molding can be performed.

Furthermore, since it is not necessary to keep the tip of the nozzle in contact with the fixed mold during molding, there is an effect that the temperature of the entire nozzle is stabilized and a molded product with excellent accuracy can be obtained. Also, since it is not necessary to set the temperature for adjusting the nozzle to a lower temperature, the temperature of the molding material in the entire interior of the nozzle does not drop, and a molded product with good transferability and high accuracy is selected. effective.

In the injection molding nozzle of the present invention, when the taper angle is 1 ° or more, when the nozzle is separated from the mold,
Or, when the mold is opened and the sprue sticks to the movable mold and moves and the sprue moves away from the nozzle,
The cold slag can be reliably removed from the nozzle without removing the cold slag from the land of the nozzle and sticking to the sprue. Since both the cold slag and the sprue are cold molding materials, there is an effect that the resin of the molding material is cut between the cold slag and the sprue, so that threading failure does not occur. Furthermore, because of this, the amount of suckback is small, so
Since almost no air is involved, voids,
There are no defects such as silver and burns.

In the injection molding nozzle of the present invention, if the taper angle of the land portion toward the inside of the nozzle is 5 ° or less, the cold slag can be used for injection.
This has the effect of entering into the mold together with the reliably injected molten molding material and preventing clogging at the land portion, thereby enabling stable continuous molding.

Further, in the injection molding nozzle of the present invention, since the nozzle is provided so as to extend along the longitudinal axis of the injection molding machine, the opening of the nozzle is straightened with the injection port of the fixed mold. Communication, injection molding is performed smoothly, when the mold opens and the sprue moves with the mold,
The cold slag does not come off the nozzle land and sticks to the sprue, leaving the cold slag reliably on the nozzle side. There is an effect that the resin of the molding material is cut off between the sprue and the sprue, and stringing does not occur.

In the injection molding method of the present invention, the length of the land portion of the nozzle attached to the tip of the cylinder of the injection molding machine is 5 mm or less, and the land portion extends toward the inside of the nozzle. Since the molding is performed using the attached injection molding machine, the cold slag remains on the nozzle side, and the molding material is cut off between the cold slag and the sprue, so that stringing does not occur.
Accordingly, the suck-back amount is small and good, and almost no air is entrapped, so that defects such as voids, silver, and burns do not occur. In addition, since the length of the land portion is short, the amount of cold slag can be reduced, and when the molten slag is injected together with the molding material, the cold slag may be clogged at the land portion having a taper angle. There is also the effect of not being present, and stable molding is possible.

Further, in the injection molding method of the present invention, if the nozzle used has a taper angle of 1 ° or more,
When the nozzle is released from the mold, or when the mold is opened and the sprue is attached to the movable mold and moves to move the sprue away from the nozzle, the cold slug is removed from the nozzle land and adheres to the sprue. Cold slag is surely left on the nozzle side without being said to follow. Since both the cold slag and the sprue are cold molding materials, there is an effect that the resin of the molding material is cut between the cold slag and the sprue, so that threading failure does not occur. In addition, since the suck-back amount is small, the air hardly gets caught, so that defects such as voids, silver, and burns do not occur.

Further, in the injection molding method of the present invention, if the taper angle of the land portion of the nozzle attached to the injection molding machine toward the inside of the nozzle is 5 ° or less, the cold slug is reduced. In addition, at the time of injection, there is an effect that the molten molding material is surely injected into the mold together with the molten molding material and does not become clogged at the land portion, thereby enabling stable continuous molding.

In the injection molding method of the present invention, since the nozzle to be used is provided so as to extend along the longitudinal axis of the injection molding machine, the opening of the nozzle is straightened to the injection port of the fixed mold. When the mold is opened and the sprue moves together with the mold, the cold slag is removed from the land of the nozzle and does not stick to the sprue. Since the slag remains on the nozzle side and the cold slag and the sprue are both cold molding materials, the resin of the molding material is cut between the cold slag and the sprue. Absent.

Further, in the injection molding method of the present invention,
Since injection molding is performed using either thermoplastic olefin-based or norbornene-based molding materials as plastic molding materials, it has the characteristic that many defects such as stringing, voids, silver, and burns occur. Even in the case of thermoplastic olefin or norbornene molding materials, high-precision, high-quality molded products can be produced by using the above-mentioned injection molding method without causing defects such as stringing, voids, silver, and burns. Obtainable.

[0063]

According to the present invention, there is provided a nozzle for an injection molding machine according to claim 1, wherein the length of the land portion of the nozzle attached to the tip of the cylinder of the injection molding machine is 5 mm or less, and Since the portion extends toward the inside of the nozzle, there is an effect that defects such as stringing, voids, silver, and burns do not occur.

In the injection molding nozzle according to the second aspect of the present invention, since the angle at which the land portion spreads toward the inside of the nozzle is 1 ° or more and 5 ° or less, stringing or voiding may occur. , Silver, burns and other defects did not occur,
There is an effect that stable continuous molding can be further achieved.

In the injection molding nozzle according to the third aspect of the present invention, since the nozzle is provided so as to extend along the longitudinal axis of the cylinder of the injection molding machine, the opening of the nozzle is fixed. Injection molding is performed smoothly, and when the mold opens and the sprue moves with the mold, the cold slag can be removed from the land of the nozzle and stick to the sprue. Thus, the cold slag remains reliably on the nozzle side, and the molding material is cut between the cold slag and the sprue, which has an effect that stringing does not occur.

In the injection molding method according to a fourth aspect of the present invention, the length of the land portion of the nozzle attached to the tip of the cylinder of the injection molding machine is 5 mm or less, and the land portion is provided inside the nozzle. Since molding is performed using an injection molding machine equipped with a nozzle that is spreading toward the head, defects such as stringing, voids, silver, and burns do not occur,
There is an effect that stable continuous molding can be further achieved.

In the injection molding method according to the fifth aspect of the present invention, since the angle at which the land portion extends toward the inside of the nozzle is 1 ° or more and 5 ° or less, stringing, voids, No defects such as silver and burns occurred,
There is an effect that stable continuous molding can be further achieved.

In the injection molding method according to a sixth aspect of the present invention, since the nozzle is provided so as to extend along the longitudinal axis of the cylinder of the injection molding machine, the opening of the nozzle is of a fixed side type. It communicates directly with the injection port, injection molding is performed smoothly smoothly, and when the mold opens and the sprue moves together with the mold, the cold slag comes off from the land of the nozzle and sticks to the sprue. The cold slag remains reliably on the nozzle side, and since both the cold slag and the sprue are cold molding materials, the effect is that the resin of the molding material is cut between the cold slag and the sprue. There is an effect that stringing does not occur.

In the injection molding method according to the seventh aspect of the present invention, since injection molding is performed using either a thermoplastic olefin-based material or a norbornene-based material as a molding material, stringing, voids, Even when using a thermoplastic olefin or norbornene-based molding material, which has a characteristic that defects such as silver and burnt are particularly likely to occur,
There is an effect that an excellent molded product with high accuracy and high quality can be obtained without generating these defects.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view around an injection molding nozzle according to the present invention.

FIG. 2 is a longitudinal sectional view around a conventional injection molding nozzle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nozzle 2 Opening part 3 Land part 4 Taper 5 Melted molding material 6 Sprue 7 Threading 8 Fixed side mold 9 Taper angle 10 Cold slag 11 Inside of tip of nozzle 12 End of sprue 13 Band heater

Claims (7)

[Claims] 1. The injection molding, wherein a length of a land portion of a nozzle attached to a tip of a cylinder of the injection molding machine is 5 mm or less, and the land portion extends toward the inside of the nozzle. Nozzle. 2. The injection molding nozzle according to claim 1, wherein the angle at which the land portion extends toward the inside of the nozzle is 1 ° or more and 5 ° or less. 3. The injection molding nozzle according to claim 1, wherein the nozzle is provided so as to extend along a longitudinal axis of a cylinder of the injection molding machine. 4. Injection wherein a nozzle provided at the tip of a cylinder of an injection molding machine has a land portion having a length of 5 mm or less, and a nozzle whose land portion extends toward the inside of the nozzle. An injection molding method, wherein molding is performed using a molding machine. 5. The injection molding method according to claim 4, wherein the angle at which the land portion extends toward the inside of the nozzle is 1 ° or more and 5 ° or less. 6. The injection molding method according to claim 4, wherein the nozzle is provided so as to extend along a longitudinal axis of a cylinder of the injection molding machine. 7. The injection molding method according to claim 4, wherein the injection molding is performed using one of a thermoplastic olefin-based material and a norbornene-based material as a molding material.