JPH0449959A - Pressing apparatus for molding artificial dental base - Google Patents

Abstract

PURPOSE:To shorten molding time with a compression molding while achieving a smaller size of the apparatus by using an air cylinder for driving made up of a hydraulic cylinder section and a pneumatic booster section when forming an artificial dental base. CONSTITUTION:Compressed air is supplied at a first port 13 to lift a mobile disc 7 on which is mounted a lower gypsum die 3 connected to a hydraulic piston 5 of a hydraulic cylinder 11 and a piston rod 9 through an air-hydraulic converter 14 in a direction of an upper gypsum die 5 at a high speed and in a short time. Then the mobile disc 7 is detected at a specified position when it approaches the upper gypsum die 5 and a compressed air is supplied at a second port 16 of a pneumatic booster 12 to drive the hydraulic piston 15 at a low speed by a high thrusting force with a switch over to a pressure intensifier by an air pressure so that the lower gypsum die 3 is pressed onto the upper gypsum die 5. With the use of an air cylinder 10 for driving combining a high speed driving and a low speed and high thrust driving for molding an artificial dental base, an efficient compression molding is accomplished with a shortening of molding time and, furthermore, a smaller size of the apparatus as a whole is achieved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a press device for producing a denture base using a thermoplastic resin, and is capable of compressing and molding a heat-softened thermoplastic resin preform to produce a denture base. The present invention relates to a press device for forming a denture base, which enables extremely efficient molding by shortening the molding time, and which can downsize the device.

[Prior Art] In recent years, methods have been developed that use engineered plastics, which have excellent mechanical strength and safety, as denture base materials. Examples include polycarbonate denture bases made by injection molding, polysulfone denture bases, and the like. However, the injection molding method requires an expensive injection molding machine to form the denture base.

On the other hand, as a method of easily molding a thermoplastic resin denture base using an inexpensive compression molding machine, a preform similar to the denture base to be manufactured is heated and softened on a plaster mold, and then compression molded. There are known methods to do this.

As an apparatus for such a compression molding method, for example, Japanese Utility Model Application Publication No. 59-57919 discloses a thermostatic chamber for heating and softening a thermoplastic resin, a guide and a guide for moving a plaster lower mold to below a plaster upper mold. A denture base manufacturing device combined with a compression molding machine is shown.

[Problem to be solved by the invention] However, in recent years, compression molding has been performed in a shorter time,
There has been a demand for more efficient production of denture bases. In this case, the apparatus described in the above-mentioned Japanese Utility Model Publication No. 59-57919 does not disclose any particular measures to shorten the compression molding time or to reduce the size of the apparatus.

[Means for Solving the Problems] Therefore, an object of the present invention is to provide a press device that can efficiently perform compression molding in denture base manufacturing, shorten molding time, and downsize the device. be.

According to the present invention, an upper fixed plate on which a plaster upper mold holding an artificial tooth is attached, a plaster lower mold on which a pre-softened thermoplastic resin preform is mounted, and the above-mentioned It mainly consists of a movable plate located below the upper fixed plate, and a driving air cylinder whose main body is attached to the lower fixed plate so as to hang down and whose piston rod tip is fixed to the movable plate, and as the driving air cylinder, This can be achieved by a press device for forming a denture base that uses an integrated hydraulic drive cylinder and pneumatic booster.

[Operation] The denture base molding press device of the present invention lifts a lower plaster mold on which a heat-softened thermoplastic resin preform is placed in the direction of a fixed upper plaster mold through a movable platen, and places it on a plaster upper mold. The method is characterized in that a driving air cylinder with a specific structure is used when crimping and forming a denture base.

That is, this driving air cylinder basically consists of a hydraulic cylinder section and a pneumatic booster section,
The effect will be briefly explained below.

First, at the beginning, compressed air was supplied from the first port to move the movable platen (attached to the plaster mold) connected to the hydraulic piston and piston rod of the hydraulic cylinder section through the air-hydraulic conversion mechanism at high speed. and raise it toward the top of the plaster mold in a short time. Next, the movable platen detects this at a predetermined position close to the plaster mold, and then supplies compressed air from the second boat of the pneumatic booster section, switches to the pneumatic pressure booster cylinder, and moves the hydraulic piston at a low speed. - Press the lower plaster mold to the upper plaster mold with high thrust.

By using a driving air cylinder that combines high-speed drive and low-speed/high-thrust drive for denture base molding, it is possible to shorten the molding time and achieve efficient compression molding of denture bases. Furthermore, it is possible to achieve miniaturization of the press apparatus as a whole. In order to obtain high thrust, a hydraulic cylinder operated by a hydraulic pump is generally used, but in this case, a hydraulic cylinder that is operated by a hydraulic pump, tank, strainer, switching valve, relief valve, and other necessary equipment is used. A unit is required, and the molding equipment becomes large-scale.

[Examples] Next, the present invention will be described in more detail based on illustrated examples, but the present invention is not limited to these examples.

FIG. 1 is a schematic side view showing an embodiment of a press device for forming a denture base according to the present invention.

In FIG. 1, ■ is a press zone in which a lower plaster mold 3 on which a thermoplastic resin preform 2 is placed and an upper plaster mold 5 containing an artificial tooth 4 are accommodated. In addition, the upper plaster mold 5 is installed on an upper fixed platen 6, and the lower plaster mold 3 is installed on a movable platen 7, and the movable platen 7 is a piston of a driving air cylinder lO that is attached to the lower fixed platen 8 to hang down. It is fixed to the tip of the rod 9 and moves up and down in the direction of the plaster mold 5. In addition, the driving air cylinder lO is
Basically, it is integrally composed of a hydraulic cylinder 11 and a pneumatic booster 12.

The pneumatic booster 12 includes a pressure increasing piston 17 and a pressure increasing ram 17a integrally fixed thereto. The hydraulic cylinder 11 is composed of a hydraulic piston 15 and its piston rod 9. Inside the piston rod 9, a hole 9a is formed which extends in the axial direction to the end and into which the pressure increasing ram 17a of the pneumatic booster 12 can be inserted. has been done. ll
a, 11b, and 12a are oil seals.

An oil inlet/outlet 26 is provided in the through hole 25 of the pressure booster ram 17a at the joint portion of the hydraulic cylinder 11 and the pneumatic booster 12, and this and the lower part of the pneumatic-hydraulic converter 14 are connected to the oil pipe 1.
4a.

The outer diameter of the pressure booster ram 17a of the pneumatic booster 12 and the inner diameter d of the through hole 25 are smaller than the outer diameter of the pressure booster piston 17 by a predetermined value. The area ratio (pressure increase ratio) of the pressure increase piston 17 is l:30
It is said that

In addition, 30 is a molding device (
Casters 30a that movably support the entire molding device 30 are attached to the lower part. Fixed at the bottom! Reference numeral 118 is fixedly attached to a horizontal member constituting a template frame (not shown) which is the framework of the molding device 30. 31 is an opening/closing door for taking the lower plaster mold 3 and the upper plaster mold 5 in and out of the press zone 1, and 32 is a control panel.

The lower fixing l118 and the upper fixing fi6 are connected with a distance maintained by two tie rods on the left and right in the front view direction (not shown), and the movable platen 7 is slidably held by these tie rods and can be raised and lowered. It is provided.

The operation of this press device will be explained below.

First, compressed air is supplied from the first boat 13 to the pneumatic-hydraulic converter 14 to apply pressure, and from this pneumatic-hydraulic converter 14 it is passed through the oil pipe 14a and the oil inlet/outlet 26 into the head chamber of the hydraulic cylinder 11 and into the hole 9a. Pressure oil into the hydraulic piston 15 (
and the movable platen 7 connected to the piston rod 9) is raised toward the plaster upper mold 5 at high speed. In addition, FIG. 1 shows the state immediately before the movable platen 7 is raised with oil. In addition, this movable platen 7 also includes a thermoplastic resin preform 2.
A lower plaster mold 3 is installed. movable fi7
When it reaches a predetermined position before contacting the plaster mold 5, this is detected by a position detection device such as a limit switch (not shown), and the pressure increase operation is then performed. In addition, in the case of no load (low pressure), the rising speed (high speed) of the movable platen 7 is normally 15 to 45 mm/sec, and the operating pressure of air is 3 to 7 kg/cm2.

For the pressure increase operation, compressed air is supplied from the second boat 16 of the pneumatic booster 12. Then, the pressure increasing ram 17a of the pneumatic booster 12 rises within the through hole 25, the oil inlet/outlet 26 is closed, and its tip enters the head chamber of the hydraulic cylinder 11.

When there is no load, when the preform 2 of the lower mold 3 is not yet in contact with the upper mold 5, the piston rod 9 (lower mold 3) rises by the volume by which the pressure increasing ram 17a rises. When the preform 2 comes into contact with the upper die 5 and a load is applied, the pressure booster ram 17a compresses the oil stored in the hydraulic cylinder 11, and the piston rod 9 of the hydraulic cylinder 11 is Press. Note that at the time when the pressure-increasing press operation is completed, a portion of the tip of the pressure-increasing ram 17a is inserted into the hole 9a of the piston rod 9. In this way, the head side area of the pressure booster piston 17 of the pneumatic booster 12 is equal to the pressure booster ram 17a.
Since the cross-sectional area of the piston rod 9 is made larger, for example, by 30 times, than the cross-sectional area of Thermoplastic resin preform 2
Compression molding is performed.

In this case, the speed (low speed) of the movable platen 7 is usually 15 to 30
ays/sec, and the press thrust is normally 2
．． Compression molding is performed as 5 to 4 tons.

After the above compression molding is completed, compressed air is supplied from the third boat 27 to the rod chamber of the pneumatic booster 12 and from the fourth boat 28 to the rod chamber of the hydraulic cylinder 11.
7a and the piston rod 9 are lowered, the movable platen 7 is lowered, the upper mold 5 and the lower mold 3 are opened, and each is taken out from the door 31. Then, the compression-molded denture base remaining on the lower mold 3 is removed from the lower mold 3 to obtain a desired denture base.

In this way, the press device of this example uses an air cylinder configured to operate with compressed air, which is easy to handle and does not require large-scale equipment, and which can obtain a high pressure increase ratio. It does not need to be large-sized, and therefore the press device is miniaturized and compactly constructed.

Therefore, the area occupied by the press device in a dental laboratory can be small, and handling operations can be performed easily.

In addition, in the apparatus of the above embodiment, as shown in FIG. A safety plate 18 is arranged as a part of the fixture 19.

In addition, when molding the denture base of the present invention, the upper plaster mold 5 and the lower plaster mold 3 are heated in advance to soften the thermoplastic resin preform 2 placed on the lower plaster mold 3.
As shown in the figure, a heating box 20 consisting of two upper and lower units each having a far-infrared heater (not shown) is inserted into the press zone l via a connecting mechanism 22 by a driving device 21 consisting of an air cylinder. In this way, the thermoplastic resin preform 2 is usually softened at about 380°C, the plaster mold 5 is kept at about 130°C, and then the heating box 2
0 will retreat from press zone l.

[Effects of the Invention] As explained above, according to the denture base molding press device according to the present invention, a driving air cylinder having a specific structure is used when molding a denture base, so that the compression molding time is reduced. It is possible to shorten the length and also to downsize the device.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of a press apparatus for forming a denture base according to the present invention. l... Press zone, 2... Thermoplastic resin preform, 3... Lower plaster mold, 4... Artificial tooth, 5... Upper plaster mold 6... Upper fixing plate, 7-.・Movable plate, 8...
Lower fixed plate 9... Piston rod, 10... Driving air cylinder, l 1-... Hydraulic cylinder, 12...
Pneumatic booster, 13--first boat, 14-- pneumatic hydraulic converter, 15-- hydraulic piston, 16-- second boat, 17-- pressure increasing piston, 17 a-- pressure increasing ram ,
18- Safety plate, 19 Fixture, 20 Heating box, 21- Drive device 22 Connection mechanism, 3
0... Molding device, 30a... Caster, 31...
Opening/closing door, 32-...control panel.

Claims (1)

[Claims] (1) An upper fixed plate to which the upper plaster mold holding the artificial tooth is attached, and a lower plaster mold on which the pre-softened thermoplastic resin preform is placed are attached, and are located below the upper fixed plate. a movable plate, a driving air cylinder whose main body is attached to a lower fixed plate hanging down, and whose piston rod tip is fixed to the movable plate;
1. A press device for forming a denture base, which is mainly comprised of: The driving air cylinder is a combination of a hydraulic driving cylinder and a pneumatic booster.