JPH0435918A - Transfer device for molding and molding method - Google Patents

Abstract

PURPOSE:To prevent strong friction and twist among piston rings and pots from being caused by a method wherein a molding material is sent into chambers through flow passages, and the molding materials in the chambers are fed under pressure into cavities through nozzles by depressing free pistons. CONSTITUTION:After a transfer device 2 and a mold 1 are clamped with a small force by the high-speed cylinder of a mold clamping device, the fixed amount of a molding material is sent from a primary nozzle 3a into chambers 23 through a communication hole 21a, a communication hole 20a and flow passages 33. when the transfer device 2 and the mold 1 are then clamped with large force by the low-speed cylinder of the mold clamping device, piston rings 17 are inserted into pots 22, and the molding materials in the chambers 23 are fed under pressure into cavities 31 through nozzles 19b, 19b. Thereafter, the mold 1 is opened by the release of the mold clamping device, and molded products are taken out of the cavities 31. In this instance, since the piston rings 17 are in a free state, strong friction and twist are not caused among the piston rings 17 and the pots 22, so that damage and dragging can be prevented.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a molding transfer device used for molding various molding materials such as rubber materials such as synthetic rubber or natural rubber, and thermosetting or thermoplastic resin materials. This article relates to an apparatus and a molding method.

C. Prior Art] Conventionally, there are various methods for molding a molding material.

For example, transfer molding is used to mold rubber materials. In transfer molding, after a preheated block of molding material is put into a chamber, the molding material in the chamber is press-fitted into a cavity by a plunger, and is left in the cavity under pressure for a certain period of time. The cured molded product is removed by opening the mold.

[What the invention tries to solve! ! [However, in the conventional molding method described above, the plunger fits into the chamber when press-fitting the molding material, but the axis of the pot that forms the chamber and the axis of the plunger may not align accurately. As a result, strong friction and abrasion occur between the inner circumferential surface of the pot and the outer circumferential surface of the plunger, resulting in damage to the pot or plunger, as well as problems such as galling or seizure. .

Additionally, rubber materials generally have poor fluidity. Therefore, in the conventional molding method described above, when the molding material is simultaneously press-fitted into a plurality of cavities through a plurality of nozzles, the amount of press-fitting into each cavity is not uniform. In particular, cavities located in the periphery away from the chamber are likely to be short-circuited. Further, the sticky rubber material tends to accumulate near the inlet of the nozzle, resulting in the problem that the accumulated rubber material hardens and mixes into the molded product.

In view of the above-mentioned problems, an object of the present invention is to provide a molding transfer device and a molding method that prevent strong friction and strain from occurring between a plunger for press-fitting a molding material and a pot. ing.

The object of the present invention is to provide a molding transfer device in which the amount of press-fitting into a plurality of cavities becomes uniform.

[Means to solve the problem]

In order to solve the above-mentioned problem, the molding transfer device according to the invention of claim 1 includes a pot having a nozzle for pressure-feeding the molding material into the cavity, a chamber communicating with the nozzle, and a molding material in the chamber. a flow path for feeding a material; a free piston provided in the bond for changing the volume of the chamber and press-fitting the molding material in the chamber into the cavity through the nozzle; and the free piston. and a base plate for pressing.

In the molding transfer device according to the invention of claim 2, the chamber is provided in an annular shape so as to communicate with a plurality of nozzles, and the free piston is provided in an annular shape so as to fit into the chamber. The flow path is provided radially from the center of the pot to the chamber.

The molding method according to the invention of claim 3 includes a flow path for feeding molding material into a chamber communicating with a nozzle, and a free piston fitted into the chamber so as to be able to vary the volume of the chamber. A molding method in which a molding material is press-fitted into a cavity by a transfer method, comprising a step of sending the molding material into a chamber through the flow path, and a step of pressing the free piston to push the molding material in the chamber. and press-fitting into the cavity through the nozzle.

[Function] The free piston reduces the volume of the chamber by being pressed by the base plate, thereby forcing the molding material in the chamber into the cavity.

Since the free piston is not fixed to other members such as the ram of the hydraulic cylinder, no unbalanced load due to external force is applied between the free piston and the pot.

If the chamber is annular, the length of the flow path for the injected molding material to reach the chamber is constant,
The pressure balance of the molding material to each chamber is improved.

〔Example〕

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

FIG. 1 is a cross-sectional front view of a transfer device 2 according to the present invention, and FIG. 2 is a cross-sectional view of the transfer device 2 in FIG. 1 taken along the line -■.

The transfer device 2 is composed of a nozzle temperature control plate 14, a cylinder plate 15, a cylinder ring plate 16, a piston ring 17, a base 18, a secondary nozzle 19, etc. Below the transfer device 2, the molds 1, such as a lower mold 11, an upper mold 12, and a mold temperature control plate 13, are arranged.

The upper mold 12, the mold temperature control plate 13, the nozzle temperature control plate 14, the cylinder plate 15, and the cylinder ring plate 16 are integrally connected to each other by bolts (not shown). The base 18 is connected to the base 18 by bolts or the like (not shown) so as not to be separated by more than a certain distance in the vertical direction of FIG. 1, and to be able to move toward and away from within that distance.

The secondary nozzle 19 is fixed to the cylinder plate 15 by bolts (not shown).

The entire transfer device 2 and mold 1 are attached to a hydraulic mold clamping device (not shown), and the lower mold 11 is attached to a mold temperature control plate provided on the base plate below the mold clamping device. The base 18 is also attached to the upper board with bolts or the like.

A cavity 31 is formed between the lower mold 11 and the upper mold 12.

The mold temperature control plate 13 is provided with a heater (not shown), and the upper mold 12 is heated by passing a current through the heater.
and adjust the temperature to the appropriate temperature to harden the molding material.

The nozzle temperature control plate 14 is provided with an oil path (not shown) for circulating temperature control oil to an oil path (not shown) formed in the secondary nozzle 19, thereby adjusting the temperature of the secondary nozzle 19. do.

The cylinder plate 15 includes a plate portion 15a having a substantially square outer shape and a cylinder portion 15b having a circular outer shape.

The plate portion 15a has a nozzle hole 19 for the secondary nozzle 19.
A large number of nozzle holes 19b, 19b... communicate with
They are provided at equal intervals in the circumferential direction on the same circumference.

A tapered hole 32 is provided in the center of the cylinder portion 15b, and a cylinder nozzle 20, which has a cylindrical flow hole 20a in the center, is attached to the tapered hole 32 by a bolt (not shown). .

The cylinder nozzle 20 is provided with a pressure relief nozzle 21 that is slidable in the axial direction within the communication hole 2Oa.

The pressure relief nozzle 21 is provided with a communication hole 21a at the center and a tapered surface 21b at the upper end.

A tapered end portion of a primary nozzle 3a attached to the end of an injection head (not shown) can come into close contact with the tapered surface 21b of the pressure relief nozzle 21 from above in the axial direction.

Further, in the cylinder portion 15b, a large number of channels 33, 33, . These channels 33 are provided at equal angles to each other, and are provided to open approximately at the center of the upper end opening of the nozzle hole 19b provided in the plate portion 15a.

The cylinder ring plate 16 includes the plate portion 1 described above.
A cylinder hole 16a having an inner diameter larger than the outer diameter of the outer circumferential surface 15c of the cylinder 5a is provided concentrically with the outer circumferential surface 15C.

A pot 22 is formed by the outer circumferential surface 15c of the cylinder portion 15b, a part of the upper surface 15d of the plate portion 15a, and the cylinder hole 16a of the cylinder ring plate 16, and an annular chamber 23 is formed inside the pot 22. has been done. Note that the above-mentioned nozzle hole 19b is located on the top surface 1.
5d, that is, the nozzle hole 19b communicates with the chamber 23.

The piston ring 17 is attached to the outer peripheral surface 15 of the cylinder portion 15b.
c and the cylinder hole 16a of the cylinder ring plate 16 with a slight clearance,
It can be slid in the axial direction. The volume of the chamber 23 is varied by moving the piston ring 17 in the axial direction.

That is, the piston ring 17 is not fixed to other members, and the installation described later is performed by being pressed by the base 18 and fitting into the chamber 23.
3 constitutes a free piston for force-feeding the molding material in the cavity 31 and press-fitting it into the cavity 31.

For installation, a hole 18a is provided on the base 1 to prevent interference with the cylinder nozzle 20, pressure relief nozzle 21, primary nozzle 3a, etc. mentioned above.
8 moves in the direction of arrow M1 relative to the cylinder ring plate 16, the piston ring 17
Press.

In the state shown in FIG. 1, the mounting is performed on the lower surface 18.
Although the upper surfaces 15e and 16b of the cylinder plate 15 and the cylinder ring plate 16 are separated from each other, when the base 18 presses the piston ring 17 completely, these surfaces come into contact with each other. In this state, the piston ring 17 is completely fitted into the bot 22, but the piston ring 17
The opening of the flow path 33 to c is prevented from being completely blocked.

In addition, when installing the piston ring 17 to the bot 2, the base 18 and the cylinder plate 15 are at the farthest distance from each other.
It is designed so that it will not be removed from 2.

The secondary nozzle 19 is provided with a nozzle hole 19a that communicates with the above-mentioned nozzle hole 19b, and the nozzle hole 19a communicates with the above-mentioned cavity 31.

In addition, the communication hole 21a, the tapered hole 32, the chamber 23,
The nozzle holes 19a, 19b, etc. have tapered surfaces, rounded surfaces, etc. formed at appropriate locations so that the molding material flows smoothly.

The above-mentioned transfer device 2 is used in the field of molding rubber materials.
It is called RB (cold runner block), and in the field of synthetic resin molding it is called HRB (hot runner block). In addition, the transfer device 2 and the mold 1
Sometimes the whole is called a mold.

Next, a molding method using the transfer device 2 configured as described above will be explained.

First, the transfer device 2 and the mold 1 are closed with a weak force by the high-speed cylinder of the mold clamping device. At this time, the base 18, cylinder plate 15, and cylinder ring plate 16 are in contact with each other during installation.

The injection head (not shown) descends, and the primary nozzle 3a attached to its tip comes into contact with the pressure relief nozzle 21, and then from the primary nozzle 3a, the flow hole 21a,
A certain amount of molding material is fed into the chamber 23 through the communication hole 20a and the flow path 33.

As a result, the pressure inside the chamber 23 increases, and the
The pressure causes the piston ring 17 to move upward (arrow M2
As a result, the space between the base 18 and the cylinder plate 15 opens against the mold clamping force of the mold clamping device.

Next, the transfer device 2 is
And the mold 1 is clamped. As a result, the piston ring 17 is fitted into the bot 22, and the molding material in the chamber 23 is press-fitted into the cavity 31 through the nozzle holes 19b, 19b.

After the molding material is press-fitted into the cavity 31, it is left under pressure for a certain period of time, thereby hardening the molding material.

During this period, the pressure relief nozzle 21 and the primary nozzle 3a move upward against the gravity of the injection head to which the primary nozzle 3a is attached due to the increase in the pressure inside the cavity 31, and the internal volume increases due to this. The punching is performed, and the so-called drooping phenomenon that tends to occur when the mold 1 is opened is prevented.

The mold 1 is opened by opening the mold clamping device, and the cavity 3 is opened.
A molded product is taken out from 1.

According to the embodiment described above, since the piston ring 17 is free, strong friction or twisting does not occur between the piston ring 17 and the pot 22, and the outer circumferential surface 15c of the piston ring 17 and the pot 22 or the cylinder hole 16a is free. No damage or galling.

According to the embodiments described above, the cavity 31.secondary nozzle 1
9. Since the positional conditions of the nozzle holes 19a and 19b are equal to each other, and the annular chamber 23 is commonly communicated with each nozzle hole 19b, the water is supplied from the primary nozzle 3a. The fluidity of the molding material is extremely smooth, and the volume of the cavity 31 is, for example, 2cc.
Even if the degree of press-fitting is small, the press-fitting amount into each cavity 31 is well balanced and the amount of press-fitting is uniform. Therefore, short shots etc. are less likely to occur.

In addition, since the opening of the flow path 33 and the opening of the nozzle hole 19b in the chamber 23 are misaligned with each other, and the fluidity of the molding material in the chamber 23 is good, there is no stagnation of the molding material. The hardened molding material does not get mixed into the molded product.

Since the volume of the chamber 23 is varied by the movement of the piston ring 17, it is possible to accommodate cavities 31 of various volumes.

By increasing or decreasing the pressure receiving area of the piston ring 17, the pressing force of the molding material can be variously changed.

Since the piston ring 17 has an annular shape, its posture within the pot 22 is stable.

Since the flow path from the chamber 23 to the cavity 31 via the nozzle holes 19b and 19a is almost linear, pressure loss is small when the molding material is press-fitted by the piston ring 17, and the mold clamping force of the mold clamping device is effective. There is no unnecessary loss of power.

Furthermore, since stress concentration does not occur in these channels during press-fitting, damage to the transfer device 2 and the mold 1 does not occur, and the design of the transfer device 2 and the mold 1 is easy.

The pot 22 is attached to the plate portion 15 of the cylinder plate 15.
Since it is formed by the upper surface 15d1 of a, the outer circumferential surface 15c of the cylinder portion 15b, and the cylinder hole 16a of the cylinder ring plate 16, its structure is simple, easy to process, and strong. In particular, when machining the flow path 33, it can be easily machined from the outer circumferential surface 15c of the cylinder portion 15b using a drill.

Since the connection with the tip of the primary nozzle 3a is made by the tapered surface 21b of the pressure relief nozzle 21, there is no possibility of the primary nozzle 3a becoming stiff due to movement in the axial direction.
Moreover, the pressure is relieved by moving the pressure relief nozzle 21, and the nasal drip phenomenon is prevented.

In the above-described embodiment, the chamber 23 is provided in an annular shape, but it may be provided independently for each secondary nozzle 19. In that case, for example, the chamber is made cylindrical, and the free piston is attached to it. It can have a cylindrical shape that fits. The number of secondary nozzles 1.9, flow paths 33, etc. may be one or an arbitrary number.

In order to feed the molding material into the chamber 23, an injection head having a primary nozzle 3a was used.
Various other devices or methods may also be used.

In addition, the structure and shape of each part such as the transfer device 2 and the mold 1,
The dimensions, number, material, position, etc. can be changed in various ways other than those described above.

The present invention can be used for molding rubber materials, resin materials, and other various molding materials.

〔Effect of the invention〕

According to the present invention, it is possible to prevent the occurrence of severe friction or strain between the piston ring and the pot.

In particular, according to the second aspect of the invention, the fluidity of the molding material is good, and the amount of press-fitting into the plurality of cavities becomes uniform.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional front view of a transfer device according to the present invention, and FIG. 2 is a cross-sectional view of the transfer device of FIG. 1 taken along the line -■. 1...Mold, 2...Transfer device (transfer device for molding), 17...Piston ring (free piston) 18...Base (base plate) for installation, 19a, 19b...Nozzle hole (nozzle), 22...pot, 23...chamber 31...cavity, 33...channel. Applicant: R-Chick Co., Ltd.

Claims (3)

[Claims] (1) A pot having a nozzle for force-feeding molding material into the cavity, a chamber communicating with the nozzle, a flow path for feeding the molding material into the chamber, and a flow path provided in the pot and having a chamber communicating with the chamber. A molding device comprising: a free piston whose volume is variable and press-fits the molding material in the chamber into the cavity through the nozzle; and a base plate that presses the free piston. Transfer device. (2) The chamber is provided in an annular shape so as to communicate with a plurality of nozzles, the free piston is formed in an annular shape so as to fit into the chamber, and the flow path is The molding transfer device according to claim 1, wherein the molding transfer device is provided radially from the center of the pot to the chamber. (3) A method for transporting the molding material, comprising a flow path for feeding the molding material into a chamber communicating with the nozzle, and a free piston fitted into the chamber to be able to vary the volume of the chamber. A molding method in which the molding material is press-fitted into the cavity through the nozzle, comprising the steps of: feeding the molding material into the chamber through the flow path; and pressing the free piston to force the molding material in the chamber into the cavity through the nozzle. A molding method comprising a step of press-fitting.