JPS606767B2 - Manufacturing method of ultra-hard resin products such as industrial prototype models - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for manufacturing resin products such as industrial prototype models and denture models.

Conventionally, all resin products such as industrial prototype models and denture models have been manufactured using molds. That is, a method has been adopted in which upper and lower molds are prepared that match the shape of the product to be manufactured, and a plastic material is poured between the molds and pressed into the desired shape.

However, manufacturing methods using these molds have drawbacks such as being expensive and difficult to modify.

Therefore, ``for a long time there has been a need for a simpler and more precise manufacturing method and apparatus in place of these known means.

The main object of the present invention is to provide an economical and highly precise method for manufacturing resin products for models.

Furthermore, a second object of the present invention is to provide a method for manufacturing a resin product that allows the shape to be modified very easily by using a wax model.

A third object is to provide an apparatus specially adapted for use in the manufacturing method of the invention. lastly,
It is an object of the present invention to provide a device that has resin injection speed, pressure, temperature, sprue runner diameter, etc. that are most common in the manufacturing process.

The method and apparatus of this invention can be used for a wide variety of purposes including industrial sampling models L dentures, trays, kitchen utensils, and the like.

The technical means to realize the idea of this invention are to put a wax model into a flask, to put plaster into the flask, to heat the wax model until it melts after the plaster has hardened, and to heat the wax model until it melts. It is formed by a special process that involves draining the wax model out of the flask, injecting resin into the space created by the wax model, and cooling the resin until it hardens. The structure of the present invention will be explained in detail with reference to the accompanying drawings as follows.

1 to 3 are drawings showing embodiments of the apparatus of the present invention.

First, a wax model 1 having the dimensions and shape of a resin product to be manufactured and a flask 2 divided into upper and lower parts 2a and 2b are prepared.

The flask 2 is divided into an upper and lower lid 11 and a side body 12.

These parts are typically fully joined by joining means 8, such as bolts 3 and nuts 14.

A hole 4 for press-fitting resin injection is formed in the side body 12 so that melted wax can flow out from the injection hole 4. The number of injection holes 4 is not limited.

However, when two or more holes 4 are formed, all holes 4 other than one hole 4 into which the resin is injected and press-fit must be tightly sealed with a plug 15 during the injection and press-fitting of the resin.

A gypsum injection port 9 is formed in the upper lid of the upper flask. The plug 16 is removably connected to the injection port 9.

The wax model 1 is placed on the inside of the bottom of the lower flask 2b.

The resin press-fitting gate 5 is formed by connecting the wax model 1 to the resin press-fitting hole 4 with wax.

The cooling pipe 6 is housed inside the lower flask 2b so that both ends thereof are connected to a closing part 7 formed on the side of the flask 2.

The upper flask 2a is placed on the upper surface of the lower flask 2b, and the upper and lower flasks 2a and 2b are joined together by a joining means 8 as shown in FIG.

As shown in FIG. 4, the wax model 1' is embedded and fixed in a superhard gypsum bed 3 formed on the inner bottom surface of the lower flask 2b. The wax prototype may be a composite of Kawama wax and a soft resin. The upper flask 2a of the flask 2 is mounted on the upper surface of the lower flask 2b, and the upper and lower parts of the flask 2 are tightly joined by a joining means so that the flasks 2 can be brought into close contact with each other as shown in FIG.

However, as shown in FIG. 3, the resin injection press-fit gate 5 is formed with the wax model 1 housed in the lower flask 2b. The resin is indirectly flowed to the injection press-fit hole 4.

The cooling pipe 6 is provided inside the flask 2, with both ends opening to the outside air through holes 7 provided at the upper end of the frame of the lower flask 2b.

It is desirable that this cooling pipe 6 has as much pressure resistance and heat resistance as possible. Of course, it is also possible for the flask 2 to have two or more cooling pipes.

Next, FIGS. 4 to 7 are explanatory diagrams of the method of the present invention, showing the steps used in this method.

First, the wax pattern 1 is placed in a flask 2 and the flask 2 is tightly joined by the means described above.

The gypsum is poured into the flask 2 through the entrance 7 until the inside of the flask 2 is filled, and the cooling pipe 6 and gate 5 are embedded in the gypsum 10 as shown in FIG. plaster 10
Waiting for the wax to harden, the flask 2 is heated until the wax inside is melted. This condition is shown in FIG. This melted wax is then allowed to flow out through the holes 4 and is flushed out of the flask 2 with hot water.
Note that the flask 2 may be heated by circulating hot water or steam through the cooling pipe 6.

The flask 2 is cooled by circulating cold water through the cooling pipe 6. Referring to FIG. 7, one of the two resin injection press-fit holes is tightly sealed and the flask 2 is turned over so that the injection hole 4 is on top. Then there's Acre 1 Knock Resin, polycarbonate, Polynaide Resin, and Stellene. A European resin material such as resin, porsentan resin, or polyester resin is injected and press-fitted through the injection press-fitting opening 4 using an injection molding machine. At this time, it is desirable to apply a resin mold release agent into the flask before injection press-fitting the European resin material.
This is because the process of removing the material from the plaster 10 can be quickly carried out. After the resin material is cured until it is molded into the resin product a, the flask 2 is separated and the plaster 10 is removed to obtain the product 1. The resulting product is polished and finished in the usual manner. 8th
The figures up to FIG. 10 show two examples of this invention, and show that a set of tooth rows is created based on the idea of this invention.

A wax model 21 of a tooth row is also housed in a lower flask 22 consisting of a bottom plate 22a and a lower collar 22b. As shown in FIG. 8, the wax pattern 21 includes an injection gate 26 connecting the injection port 24 and the wax pattern 21, and a pouring gate 27, both of which are made of wax. Furthermore, the upper flask 23 consists of an upper collar 23b and an upper plate 23a.
3 and the lower flask are placed so as to constitute a complete flask, and are tightly joined by joining means as shown in FIGS. 9 and 10.

Such flasks are preferably designed to have a pressure resistance of 1000 to 1500 k9'.

The upper and lower collars 23b and 22b are provided with a pouring port 25 on the opposite side to the filling port 24. sex exit 25
A stopper 31 is inserted into the flask to hold the resin material that is injected and press-fitted into the flask. It is preferable that this 100mm tube 31 is provided with an air vent 32 so that air can be removed if air remains in the flask. Once the flasks are connected together, gypsum is poured into the flask through the opening □29. This closure 29 is then sealed with a stopper 30.

The gypsum is filled into flasks using vacuum devesuring or vibration methods or commonly known injection methods. The plaster poured into the flask waits until it hardens, and once it hardens, it is heated until the wax model 21 melts. Then, in order to make it easier to take out the resin product made from the plaster mold, a resin molding agent is injected through the injection port 24 so as to evenly cover the inner surface of the plaster. Before injecting the resin liquid, the flask is turned over on its side so that the injection pressure port 24 is located at the top and the spout ports 25 each having a stopper 31 at the bottom.

Then, the resin liquid is injected into the flask. The conditions required for this injection molding are the injection speed of the resin liquid from 0.01 to 10/
seconds, injection pressure 30-1200k9' holding pressure time 0.05
~60/sec is desirable.

Furthermore, the diameter of the injection gate or the same circumferential diameter is 0.5-2
00 side, the diameter of the air deaeration hole or the same circumferential diameter is 0.1 to 5
◇It is desirable that the material is skin, and if the condition is below or above this condition, injection molding of the resin liquid will not be carried out sufficiently. The resin product can be removed from the plaster after the resin liquid has hardened.

Since this invention is composed of a method including the above-mentioned steps, in the case of the conventional manufacturing method of dental prosthesis, burrs are generated from the upper and lower mating parts because it is a simple pouring method or inner wax molding method. In addition, the dentition, which is temporarily fixed in the hardened plaster inside, tends to become misaligned, and the process of removing and polishing is not only time consuming but also poor in accuracy.

This problem was solved by injection molding a super hard resin liquid into the plaster cavity. Furthermore, if conventional industrial sampling is used, it becomes a simple plaster mold, which can be produced at a lower cost and with greater precision than when using a conventional real mold.

In addition, for medical purposes other than dentistry, for example, when creating a prosthetic joint due to a bone defect in the foot joint, it is possible to manufacture a resin prosthetic limb using the same method as this method. The uses are wide-ranging. Note that the term "soft resin" used in this text refers to a resin liquid that has become a soft liquid, and after hardening, it becomes a "super hard resin." Furthermore, Patent No. 1003
Specification No. 31 describes gypsum molding in which a female plaster mold is imprinted with a plastic material obtained by adding water to a mixture of gypsum starch and common salt, kneading it, and solidifying the female plaster mold by filling it with ordinary plaster. A method of manufacturing a user-type mold has been proposed.

However, the purpose of the above-mentioned product is to fill plaster with a stable cooling and solidification reaction, and because it is a plaster female mold formed by an impression, it cannot be used for manufacturing resin products that easily lose their properties and change their condition greatly. It is not durable, and it cannot be manufactured into a product with a shape that can be pulled out, so its uses are extremely limited.

Furthermore, since the plaster female mold formed by the impression has a large opening, the cooling and hardening reaction of the resin varies, resulting in unevenness of the product, and the surface becomes rough and burrs are likely to form.

Also, a mixture of gypsum starch and common salt that has been strained and softened by adding water will easily fracture, and the injection pressure of the resin will be limited to a very low level, and the resin will not be able to flow into the fine details, resulting in poor surface conditions. becomes. However, in the present invention, a model made of a material such as wax that can be melted and discharged is housed in a pressure flask, and the pressure flask is connected by a gate provided on the side of the pressure flask and a gate made of the same material as the model. The model and gate are injected into the interior and the model and gate are buried, and after the plaster hardens, the model and gate are melted and discharged to form a plaster mold that surrounds the cavity of the model space. When resin is injected into the mold through a narrow pent hole, the cooling and hardening reaction of the resin becomes stable, the resin spreads to every corner of the cavity, and the surface becomes delicate and highly accurate.

Since the resin product is obtained by crushing the plaster after the resin hardens, it is possible to obtain high-quality products of any shape or custom made dentures, rhomboid joints, prosthetic limbs, etc.Furthermore, in the present invention, the softened The synthetic resin is injected from the opening of the pressure flask through the plaster gate hole into the cavity of the model space, and after the resin hardens, the pressure flask is divided and the plaster is crushed to obtain the resin product, so it is called a plaster female mold. The mold matches the flask and can withstand high resin injection pressure.In this way, the resin is injected under high pressure through the narrow gate hole into the female plaster mold that surrounds the cavity of the model space, so the resin injection is difficult. The conditions are desirable and the resin is spread over even the smallest details, resulting in a highly accurate resin product with a delicate surface condition.In addition, in the present invention, the resin injection conditions are set to an injection speed of 0.01 to 0.01. Injection pressure 30 overnight
~1200k9 holding pressure time 0.05~6 current sand, diameter of injection gate or same circumference 0.5~20'' ribs, diameter of air deaeration hole or same circumference 0.1~5? ribs, flask Withstand pressure of 1000-1500 kg, the flow rate is set to 1000~1500 kg, so the injected resin liquid is injected into the plaster mold in a short time because it is injected through a narrow gate with a high injection pressure and air is vented through a narrow air evacuation hole. The resin product is molded at the same time as it is removed and has a delicate and clean surface.

In other words, with values other than the above values, it is difficult to manufacture resin products made from plaster molds due to the deterioration and loss of resin properties and fluctuations in the condition, and even if it is possible, it will be of extremely poor quality.

In the case of gypsum, it is difficult to apply high injection pressure to molds even if it is supported by a pressure flask, but the applicant found that by increasing the injection speed, gypsum molds can withstand high pressure for a very short period of time. was confirmed by experiment.

For example, if the injection speed is 1 to 5 seconds, the average to. It can withstand the pressure of 700 to 900 kg' crucian carp in less than 1 second. Therefore, ``increasing the injection speed has the effect of producing plaster-shaped resin products of even better quality.Also, a method for manufacturing dentures using the one-time investment method has been proposed in Tokokukan Sho 53-61194, It consists of a plunger that moves up and down by rotating the handle, and a rice cake-shaped resin housing cylinder member that allows the tip of the plunger to pass through.While rotating the handle, the resin is slowly poured into the plaster mold of the flask. After confirming that the resin is poured out from the pent during this pressurized injection process, the resin is heated and polymerized according to the proper method.

In other words, the vessel is moored at 60qC for 3 minutes and then at 100°C for 30 minutes. This is an attempt to manufacture dentures made of acrylic resin, which have been used for a long time in the dental industry, by one-time implantation. There is also a hygienic drawback as residual monomers are eluted and cause allergies.
Furthermore, it has many drawbacks such as rough surface texture (lack of beauty and sexiness) due to uneven polymerization which requires long-term heating polymerization, and is of low quality, with poor productivity and high cost.

The present invention completely eliminates the above-mentioned drawbacks that have not been overcome for many years, and uses an injection molding machine capable of super high-speed injection into a plaster mold to inject ultra-hard resin such as polycarbonate resin with a high viscosity of 0.01 to 0.0. A completely new method that allows ultra-high-speed injection in about 9 seconds, injection pressure 30-1200k9/ground, holding pressure time 0.05-6 sand, injection gate diameter 0.5-2
0? On the side, the flask was set to withstand pressure of 1000 to 1500 kg'c, and injection molding was carried out at an extremely high speed of about 0.01 to 0.5 seconds while removing air from the air deaeration hole of 0.1 to 10 mm. Therefore, there are no residual monomers, no variations in heat polymerization, high strength, and an ultra-high-quality resin product with excellent aesthetics.In addition, the surface is delicate and the interior is in a single layer state. Since it is molded, it is possible to efficiently obtain a very excellent product as a resin molded product using a plaster mold.

In this case, the plaster mold is brittle and will break immediately if the injection pressure is increased. In addition, the stone bone mold cannot be formed to a mirror surface like a mold, and the inner surface of the cavity is soft, and it has many disadvantages such as low thermal conductivity, so ultra-hard resins such as polycarbonate resin are used. It was believed that it was impossible to obtain high-quality resin products by molding with a plaster mold. This has been made possible by injection molding at an ultra-high speed of about 0.01 to 0.5 seconds, resulting in great effects.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a resin product made according to this invention;
FIG. 2 is a perspective view of a flask in an embodiment of the apparatus of this invention;
Fig. 3 is a cross-sectional view of the lower flask of the embodiment in which the wax pattern is stored, Figs. A plan view showing the wax pattern of the second embodiment stored in the lower flask, FIG. 9 a perspective view showing the assembled state of all the parts of the second embodiment, and FIG. 10 the second embodiment. FIG. 2 is an exploded view of the device. 1, 21... Wax prototype " 2... Flask, 2a,
23... Upper flask, 2b, 22... Lower flask 4, 24... Inlet, 5... Injection gate, 6... Cooling pipe, 10... Plaster , 22
a...Bottom plate, 22b...0 Lower collar, 23
a... Kamibishi, 23b...' upper collar,
25...Western outlet, 31...Bung. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10

Claims (1)

[Claims] 1. A model of the desired product shape made of a substance that can be melted and discharged, such as wax, is placed in a pressure-resistant flask, and the model and a plurality of holes provided on the side of the flask are horizontally connected by a gate formed of the substance that can be melted and discharged. Plaster is poured into a flask until the model and gate are buried, and after the plaster hardens, the model and gate are melted and discharged to form a plaster mold that surrounds the cavity of the model space. The other part is used as an air degassing hole.The softened resin is injected and press-fitted through the passage formed by the gate and the resin injection hole in the flask into the space previously formed by the model.After the resin hardens, the plaster is crushed to produce a resin product. In the method for manufacturing resin products, ultra-hard resin such as polycarbonate resin is injected into the plaster mold using an injection molding machine capable of ultra-high-speed injection at an injection pressure of 30~
Under the setting conditions of 1200 kg/cm^2, holding pressure time 0.05 to 60 seconds, injection gate diameter 0.5 to 20φmm, and flask pressure resistance 1000 to 1500 kg/cm^2, 0.
．． While removing air from the air degassing hole of 1 to 1φmm, 0.
A method for manufacturing ultra-hard resin products such as industrial prototype models, characterized by molding ultra-hard resin prototype models, prosthetic joints, prosthetic limbs, etc. by injection molding at an extremely high speed of about 0.01 to 0.5 seconds.