JPS63176122A - Runnerless injection molding equipment - Google Patents

Abstract

PURPOSE:To reduce a cost and injection pressure remarkably by simplifying constitution, by enabling heating of a gate heating device through heat transfer of heat energy from a runner heating device by forming the gate heating device of an annular material of high heat transfer properties. CONSTITUTION:A heat pipe 6a of a runner heating device 6 is held at a necessary temperature and necessary heat energy is fed also to a gate heating device 11 of a separate member coming into contact with the runner heating device 6. The gate heating device 11 is formed of copper or an metal such as copper/ beryllium or the other material whose heat conduction is favorable. Molten raw material resin is injected through an injection molding device 2 after arrival of the same at a preset temperature of the gate heating device 11. When the inside of a sprue 3 bored within a mold 4 is filled with the molten resin, the inside of a cavity 7 is filled with the resin of predetermined capacity by passing a necessary quantity through a gate 16a of a gate part 12 from a runner part 10 of the sprue 3 by an action of the injection molding device 2. Then after the filled up resin on the inside of the cavity 7 has been solidified after the lapse of a fixed period of time, a molded product is taken out by breaking a movable mold 27.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] This invention relates to a runnerless injection molding apparatus using external heating.

[Conventional technology]

Conventionally, this type of runnerless injection molding equipment, which is called a hot runner method, heats the raw material resin that accumulates or flows within the runner by placing a sharp heating element in the runner part formed in the mold. Alternatively, a heater is provided in the outer peripheral mold constituting the runner part to heat the raw resin in the runner part.

[Problem that the invention seeks to solve]

By the way, in the above-mentioned conventional example, the runner is formed integrally with the gate portion communicating with the cavity, so it is extremely difficult to control the temperature of the sharp heating element and the heater around the runner portion.

In other words, if we consider thermal energy for the sole purpose of keeping the raw material resin in the runner warm and melting it, we will not be able to properly control the solidification or semi-solidification of the minute amount of resin that is exposed to the gate, and the molded product will not be able to be opened during the mold opening operation. When taking it out, the molten resin flows out from the gate part and deteriorates the moldability.
The inconvenience of causing a runny nose is unnecessary.

To this end, the inventor has developed a special configuration called Spear System, which heats the gate section partially from the inside or outside, allowing runnerless injection molding to be performed with high precision and efficiency. Technology is in the spotlight.

However, in the case of high-speed, high-precision molding processing, a controller is required to control the temperature, and the former two have no choice but to be extremely low in cost. Although the cost is low, there is a problem in that the installation of a controller cannot be avoided.

Moreover, at present, with the development of IC technology and computer technology, there is a high dependence on using high-end and expensive computers as controllers.

(Means for Solving the Problems) This invention has been made by focusing on the above-mentioned points, and it is possible to use conventionally known raw material plasticizing means, injection molding means, and mold configurations as they are. A runner portion in the mold and a gate portion communicating with the cavity are disposed so as to penetrate on the same line, and a runner heating means for heating the runner portion and a gate heating means for heating the gate portion are formed as separate members. In addition, the gate heating means is formed of an annular material with high thermal conductivity so that the gate heating means can be heated by thermal conduction of thermal energy from the runner heating means, thereby solving the above problems.

This makes it possible to simplify temperature control by simplifying or omitting temperature control by a controller using a computer, etc., and obtain a highly accurate molded product.It also simplifies the configuration, reduces costs, and significantly lowers injection pressure. The purpose of the present invention is to provide a runnerless injection molding device that can perform the following steps.

(Operation) The thermally molten raw material obtained by the raw material plasticizing means and supplied to the runner part is subjected to a thermal action acting from the outside to the inside by the runner heating means, and the gate part is also subjected to a heat action acting from the outside to the inside by the gate heating means. Inwardly there is a vagina, which maintains a semicircular shape due to heat.

- The temperature setting of the runner heating means is determined in advance before the molding operation in consideration of heat conduction to the gate heating means, and a fixed amount of raw material is intermittently added to the runner by normal injection molding means. Runner club.

It is supplied into the cavity through the gate section.

In particular, the raw material in the gate part is not in a molten state but in a kind of semicircular state because the thermal energy supplied by heat conduction from the runner heating means is indirectly applied to the raw material in the gate part by the annular gate part heating means. The so-called gate section is always kept either open or quiet.

Therefore, each time an injection molding operation is performed, the molten resin can be smoothly injected and filled into the cavity, and even when the molded product in the cavity is taken out, the unnatural dripping phenomenon from the gate part can be avoided. Prevented.

In addition, since the runner part and the gate part are disposed so as to pass through each other on the same straight line, the injection pressure can be reduced and the injection molding operation can be carried out efficiently.

(Example) The present invention will be explained in detail below.

In Fig. 1, l denotes a means for thermoplasticizing the raw material, 2 means for injection molding the molten resin, 3 denotes a mold, especially a runner formed in a fixed mold 4, and 5 denotes two or more injection channels. The required number of heating sources such as cartridge heaters (
(not shown) are provided where necessary.

6 is an intermediate mold 8 that communicates with the manifold 5 and the cavity 7
A runner heating means disposed between the control housing section 9
It will be housed inside.

By the way, the runner heating means 6 does not need to be particularly specified, but it is possible to select a self-heating type such as a heater or a high-frequency electromagnetic induction coil, or a heat-dependent type such as a beat pipe filled with heat transfer fluid. Can be used. Self-heating types may require a controller, but heat-dependent types almost never require a controller.

In both Figures 1 and 2, a heat-dependent beat vibro a is used, and the entire body filled with thermally conductive fluid is formed in the shape of a double vibrator, and serves as the - section of the runner 3. A runner portion 10 corresponding to a straight hole with a desired diameter R1 is formed.

Reference numeral 11 denotes a gate heating means equipped with a gate part 12 that is connected to the inner heating stage F 6 and communicates with the cavity 7, and the annular collar 13 is provided at the base of the gate heating means 11, and the heat pipe roller a is It is engaged with the tip step part 14, and the narrow taper part 1
5, a gate 16a of the cavity 7 is opened through a gate hole 16 having a diameter R2 smaller than the diameter R1, and further through a tapered portion 17. The runner portion lO of the heating means 6 and the gate portion 12 of the gate heating means 11 are arranged on the same axis F, that is, on the same straight line. The gate heating means 11 is preferably made of copper, a metal such as copper, beryllium, or other material having good thermal conductivity.

Reference numeral 18 denotes a tubular support holder that firmly supports the runner heating means 6 and gate heating means 11 at the outer peripheral position, one end of which is brought into contact with the manifold 4 by a flange 19, and the other end is a tapered tip. 20 and an inner step 21 to engage with the annular collar 13 of the gate heating means 11;
And the heat pipe roller a that contacts via this annular collar 19
The structure is such that one end of the manifold 4 can be fixed by colliding with the end face portion of the manifold 4.

Reference numeral 22 denotes a positioning ring that can be engaged with the collar 19 of the support holder 18, and is used to close the minute air gap 2 in the intermediate mold 8.
3 is engaged with the stepped portion 25 of the insertion hole 24, which has substantially the same shape as the support holder 18. Reference numeral 26 denotes a temperature sensor formed of a thermocouple or the like, and is provided near the gate heating means 11.

Reference numeral 27 indicates a movable mold that can form the cavity 7 and can be opened and closed.

The operation will be explained based on the above configuration.

First, the raw material to be used is melted by thermoplasticizing means 1 to make it possible to be injection molded, and a mold, especially a stationary mold 4
The heat source provided inside the manifold 5
Thermal energy is transferred to the support holder 18 that collides with the runner heating means
A heat pipe pro-a is maintained at the required temperature.

At the same time, necessary thermal energy is also supplied to the gate heating means 11, which is a separate member, and is in contact with the runner heating means 6.

After reaching the preset temperature of the gate heating means 11, the molten raw material resin is injected by the injection molding means 2. If the runner 3 bored in the mold 4 is filled with molten resin, the injection molding means 2 will cause the necessary resin to flow from the runner section 10 of the runner 3 into the cavity 7 through the gate 16a of the gate section 12. A predetermined volume of resin is filled.

Then, after a certain period of time has elapsed and the resin filled in the cavity 7 has cooled and solidified, the movable mold 27 is opened and the molded product is taken out.

Since the above is a molding cycle of - times, the necessary number of molded products can be obtained by repeating the operation.

By the way, in this embodiment, since the heat pipe roller a is used as the runner heating means 6, the heat source for heating the heat pipe roller a is a cartridge heater or the like installed inside the mold 4, especially the manifold 5. When the necessary thermal energy is absorbed by the heating source by means of thermal conduction, this absorbed thermal energy can also be thermally conducted to the gate heating means 11 connected in contact with the tip.

Therefore, the heating temperature of the molten resin in the gate portion 12 by the gate heating means 11 becomes slightly lower, so that the molten resin exhibits a so-called semi-solid state, and the molten resin flows out from the gate 16a after taking out the molded product, causing a dripping phenomenon. can be prevented, and there is no risk of any problems occurring in subsequent repeated molding operations.

Moreover, since the runner part 10 and the gate part 12 of the runner 3 are formed in a straight line, there is an advantage that the injection pressure can be low, and since the air gap 23 is not formed,
Since dissipation of temperature and loss of thermal energy are prevented, the molding operation can be performed smoothly.

Although not shown, the gate heating means 11 is not simply brought into contact with one end surface of the runner heating means 6, but is further extended into the runner portion 10 of the runner heating means 6, so that the runner heating means 6 is connected to the gate. The runner heating means 6 may be reinforced and protected by being arranged in an annular manner around the outer periphery of the heating means 11.

Next, another embodiment of the present invention will be described based on FIG.

In this embodiment, the gate heating means 11 and the runner heating means 6 are not brought into direct contact with each other, and a coupling 28 having excellent thermal conductivity is screwed onto the open end of the support holder 18b and interposed therebetween. A reinforcing gate heating means 11 is provided on the inner side of the runner heating means 6 forming the gate 0.
There is a major difference in construction from the previous embodiment in that a hollow vibrator 29 is used which collides with the previous embodiment.

Further, the support holder 18b that collides with the manifold 5 is provided with a ring 30 and a support cylinder 31 made of a material with excellent thermal conductivity and supporting the manifold side of the runner heating means 11.

However, in this embodiment and the previous embodiment, the runner part 1 is heated using a heat pipe roller a and a heat source inside the mold 4.
0 and the gate portion 12 are heated from the outside toward the center, but the basic thermal action is the same.

Therefore, among the configurations of this embodiment, those that are substantially the same as those of the previous embodiment are given the same reference numerals, and since the functions are also the same as those of the previous embodiment, the details thereof will be omitted.

Hereinafter, two embodiments have been described for this explanation.
If the gate heating means 11 that heats the runner are each constructed from separate members, and the thermal energy of the gate heating means 11 is configured to utilize the thermal energy of the runner heating means 6, the configuration of each part will be exceptional. There is no need to be limited.1. It can be applied to anything that has the technical content described above.

(Effects of the Invention) According to the present invention, the runner part and the gate part are connected on the same straight line, and the thermal energy of the runner heating means for heating the runner part is applied directly or through another coupling to the gate part of the gate part. Since the heat is transmitted to the heating means, heat conduction and distribution are reasonable, and heat is supplied according to the diameter.

In addition, since the gate part does not have a self-heating type gate heating means and is supplied with heat from the adjacent runner heating means, it is a so-called heat-dependent type and can be provided with a simple structure, and the runner heating means Alternatively, heat energy can be obtained from a heat source within the mold by using a heat-dependent structure such as a beat vibrator, making the overall structure simple and inexpensive.

Furthermore, according to the present invention, super steel metal material can be used for the heat-dependent gate heating means, so even if other fibers such as glass fiber are mixed into the molten resin, the wear resistance can be partially improved. Since the heat conduction from the runner heating means can be improved and the heat conduction from the runner heating means can be formed using a small-volume member, the molten resin in the gate portion can be maintained in a semi-solidified state and a highly accurate injection molding operation can be performed.

Furthermore, according to the present invention, a small, small-volume gate heating means is designed and stocked in advance, and a runner heating means is prepared each time according to the size of the forming machine. Therefore, the current uneconomical situation of stocking more expensive runner heating means than necessary can be significantly improved and waste can be eliminated.

Moreover, the runner heating means has the advantage that it is possible to use not only a heat dependent type heat source such as a heat pipe, but also a self-heating type heat source of your choice such as a heater, a cartridge heater, or a high frequency electromagnetic induction heating coil.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, and FIG. 2 is a vertical sectional view showing the other side of the same. 1...Means for thermoplasticizing raw materials 2...
...Injection molding means 3 ...... Runway 4 ...... Fixed mold 5 ...... Manifold 6 ------ ...Runner heating means 7...
... Cavity 10 ... Runner section 11 ... Gate heating means 12 ... Gate section 28 ... Coupling

Claims (3)

[Claims] (1) A runnerless injection molding device that allows thermoplasticized raw materials to be injected into a desired cavity through a runner section and a gate section through a runner provided in a mold using an injection means such as a piston. The runner heating means for heating the runner part and the gate heating means for heating the gate part are formed as separate members, and the gate heating means is arranged so as to penetrate the runner part and the gate part on the same straight line. A runnerless injection molding apparatus characterized in that it is made of a highly conductive annular material and can be heated by thermal energy transmitted from the runner heating means. (2) The runnerless injection molding apparatus according to claim 1, characterized in that the runner heating means and the gate heating means are brought into direct contact to enable heat conduction. (3) The runner heating means is formed by a cylindrical heat pipe that can increase the temperature by absorbing thermal energy of a heat source that heats the mold through thermal conduction. The runnerless injection molding apparatus according to item 1.