JPH0191852A - Dental baking furnace - Google Patents

Abstract

PURPOSE:To automate continuous operation from the completion of the baking of an article to be baked to the start of the next baking, by using one furnace body so as to combine the same with a plurality of respective baking stands by a moving apparatus. CONSTITUTION:When a ceramic tooth 29a coated with a ceramic material is placed on a baking stand 20a and a program is indicated to start operation, a furnace body 21 falls by a lift apparatus 33 and the ceramic tooth 29a is heated by a heater in the furnace body 21 to perform preheating, drying and baking processes. Before the baking of the ceramic tooth 29a is completed, a worker places a ceramic tooth 29b coated with a ceramic material on a baking stand 20b to take a stand-by state. When the baking of the ceramic tooth 29a is completed, the furnace body 21 rises to the uppermost part by the lift apparatus 33 and subsequently moved along with a support 35 by a horizontal moving apparatus 22 to be positioned directly above the baking stand 20b. Then, the furnace body 21 falls according to a program and the ceramic tooth 29b is baked. Since the ceramic tooth 29a receives no radiant heat from the furnace body 21 by the movement of the furnace body 21 to the part above the baking stand 20b, said ceramic tooth 29a is rapidly cooled to a room temp. region. Then, the mounting of the next ceramic tooth can be prepared.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a dental firing furnace for firing small needles to be fired, such as dentures, in steam or air.

<Prior Art> Conventional firing furnaces of this type include those shown in FIGS. 5 and 6. This firing furnace is composed of a firing table 2 provided at a fixed position on a base 1, and a furnace body 3 provided above the firing table 2 so as to be movable up and down. The firing table 2 is a table on which a porcelain tooth or a denture (hereinafter referred to as a porcelain tooth) such as an original cast body to become a porcelain tooth is placed. The furnace body 3 has an internal space 4 that opens downward, and a heater (
Not shown. ), and in the lowered position, the lower edge of the furnace body 3 is in close contact with the edge of the stage 5 on which the firing table 2 is placed via the seal rubber 6, and the outside air is cut off, making the interior airtight. It is designed to be preserved. In addition, in addition to the one shown in the figure, the furnace body is set in a fixed position and the firing table is moved up and down, and when the firing table is raised, the periphery of the stage touches the bottom periphery of the furnace body through the seal rubber. There are also structures that allow close contact to maintain airtightness.

Although detailed explanations will be omitted, such firing furnaces perform extremely labor-intensive firing processes such as discasing, firing of metal conditioners, firing of opaque porcelain, firing of crown-colored porcelain, and glazing. The firing process is a complex process that involves maintaining the material at a specified temperature for a specified period of time, slowly cooling it after heating, and pre-drying. For this purpose, although not shown in the drawings, a control unit is provided, and the firing is performed according to a predetermined program inputted to operate the electric heater in the furnace body 3, raise and lower the furnace body 3, supply and exhaust air to the internal space 4, etc. One firing process is automatically performed, from placing all the objects to be fired on the stand, firing them, and taking them out. Normally, a program allows you to enter a number of settings and select and use them for each firing.

Δ The following is an example of a series of steps until the completion of porcelain tooth firing.

(1) Call up the necessary programs that have been set and inputted in advance, place the porcelain tooth 7 coated with porcelain on the firing table 2, and turn on the start switch.

(2) The furnace body 3 is lowered to a drying position determined at an appropriate position above the baking table 2.

(3) Adjust the internal temperature of the furnace body to an appropriate temperature (-600~
700"C) and dry for 1 to several minutes. At this time, the temperature of the porcelain tooth 7 on the firing table 2 becomes 150 to 200°C.

(4) Next, a drying process is performed in which the furnace body 3 is gradually lowered while maintaining the temperature of the internal space 4 at 600 to 700°C, usually over a period of several minutes.

(5) After the furnace body 3 has completely cooled down, the temperature of the internal space 4 is increased at a rate of 30 to 100°C per minute, and the temperature of the porcelain tooth is increased to a temperature range of 950 to 1100°C over several minutes. Heat until.

(6) During the heating of the porcelain tooth in (5) above 950
When the temperature reaches ~1100'C, the internal space 4 kept in an airtight state is heated to -55~-76αHg (
Reduce the pressure to a vacuum (gauge pressure). 8 in the figure is an exhaust port. Note that in some cases, the vacuum may not be applied. In this vacuum state or in the atmosphere, porcelain tooth '7 'rl 2
It is heated for ~10 minutes. This heating is essentially firing. (7) Next, the furnace body 3 is raised rapidly, the porcelain tooth is taken out from the firing table, placed on another porcelain coating work table, and the porcelain tooth is again coated with porcelain. Apply. During this time, the furnace body 3 is at the highest position, heating the first firing table 2.

(8) After the firing in (6) and before the operation in (7), a step of slowly cooling the porcelain tooth may be inserted depending on the type of porcelain material and the difference in the firing process. In that case, the temperature of the internal space 4 is maintained at 500 to 700°C, and the furnace body 3 is
After raising the furnace body 3 to its highest position and exposing the porcelain teeth on the firing table to the atmosphere, the furnace body 3 is lowered again and completely closed, and a predetermined temperature (generally 500 to 700°C) is maintained. Cool slowly (9) After step (7) above, a preset and input program is called up using the input means, and the same process as above is usually repeated several times to complete the firing of the porcelain tooth.

Depending on the type of porcelain tooth and the difference in firing method, (in steps 11 to (9)), step (7) may be omitted, and after steps (6) and (8), the furnace body 3 may be raised and fired once. Sometimes it ends with just that.

In Figures 5 and 6, 9 is a viewing window, 10 is a column, 1
1 is a guide rail, 12 is a rail, and 13 is a cushion rubber.

<Problems to be Solved by the Invention> The above-mentioned conventional pre-firing furnace which is composed of one baking table and one corresponding furnace body has the following problems.

When firing dental porcelain, it is common knowledge to cool it down to room temperature immediately after firing. This is a necessary consideration to avoid leaving large strains due to expansion and contraction between the ceramic and metal. However, in conventional dental firing furnaces, after the completion of firing the dental porcelain and when taking out the fired product from the furnace body, the furnace body is fully opened directly above the firing table, and heat radiation from the residual heat of the furnace body is released into the furnace. Since it is added to the baked product directly under the body and the baking table, radiant heat cannot be avoided as it is. For this reason, workers had to manually transfer the fired products from the firing table to another work space immediately after the furnace body and firing table were opened. When fired, it is in a wet state, and as a step before firing, it is gradually dried on a firing table using the radiant heat of the furnace, but the built-up product may not break due to rapid heating. The firing platform required sufficient cooling to prevent cracking. That is, the firing table is in a high temperature state immediately after all the fired products are collected. It takes a lot of time to cool it down, and it is inconvenient that the next fired product cannot be dried immediately after the previous firing is completed.

Means for Solving the Problem> The means of the present invention includes a plurality of firing tables on which objects to be fired are placed;
A furnace body that opens downward and is formed in a size that can cover any of the firing tables, and any one of the plurality of firing tables that is provided for one or both of the plurality of firing tables and the furnace body. It is characterized by comprising a moving device configured to be able to change and move the selected firing table between a state where it is located directly below the furnace body and a state where the selected one firing table is covered by the furnace body. .

<Operation> The basic firing cycle of the dental firing furnace equipped with the above means is as follows. That is, the object to be fired is placed on one of the firing tables, and the firing table is moved by a moving device so that it is positioned directly below the furnace body. In order to move on to the actual firing process after the drying and preheating steps, the furnace body and firing table are appropriately moved by a moving device in a direction toward each other, so that the furnace body covers the firing table. Between this drying and preheating step and the firing step, the object to be fired next is placed on another firing table and kept in a standby state. When the firing of the object to be fired on the firing table covered with the furnace body is completed, the firing table and the furnace body are moved vertically away from each other using a moving device, and the firing table in standby state is moved to the furnace using the moving device. The firing table, on which the fired products are placed, is moved to a position away from directly under the furnace body. In this state, the object to be fired on the firing table located directly below the furnace body is dried and preheated by the radiant heat of the furnace body, and the firing object on the firing table located outside the furnace body is heated. This is a state in which the finished product is cooled at room temperature without receiving radiant heat from the furnace body. Therefore, the fired product should be immediately cooled as it is, and replaced with another fired product at an appropriate time after cooling to room temperature, or if the same fired product is to be coated with porcelain and refired, the coating should be changed. and leave it in standby mode. During this time, the object to be fired on the firing table located directly below the furnace body undergoes drying and preheating, and undergoes substantial firing.

In such a firing cycle, the handling of the objects to be fired can be automated, except for the work of placing the objects on standby on the firing table and the work of taking out the cooled fired products from the firing table. In addition, this manual work requires time.

<Example> A first example will be described using FIGS. 1 to 4. In the figure, 2oa and 2ob are firing tables, 21 is a furnace body, and 22
is a mobile device.

The two firing tables 20a and 20b are of the same size and are placed at regular positions on the base 24 with an interval between them. Each of the firing tables 20a and 20b is similar to the firing table 2 in the conventional firing furnace shown in FIGS. 5 and 6, and is provided on stages 25a and 25b. In the figure, 26 is seal rubber, 27 is cushion rubber, 28
is a tray, and z9a and z9b are porcelain teeth to be fired.

The furnace body 21 is formed in a size that can cover one of the firing tables 2oa and 2ob, and is open downward, and is similar to the conventional furnace body 3 described above. 30 in the figure is the furnace body 21
31 is an air supply/exhaust port, and 32 is a bundle of hoses, electric wires, etc.

In this embodiment, the moving device 22 is composed of a lifting device 33 and a horizontal moving device 34. Lifting movement device 33
The furnace body 21 is moved up and down, and the furnace body 21 is supported by a support column 35 so as to move up and down along a guide rail 36 provided on a support column 35 that stands up from a base 24. The screw is screwed into a nut provided on the furnace body 21 side, and the feed screw is rotated by an electric motor. The horizontal movement device 34 is provided at the lower part of the support 35 and moves the support 35 horizontally together with the furnace body 21.A guide for guiding the support 35 in the horizontal direction is provided on the base 24, and the support 35 is moved parallel to the guide. A feed screw is provided on the base 24, and the screw nut is connected to the support 35, and the feed screw is rotated by an electric motor. In the figure, 37 is a bellows provided as a dustproof cover.

In addition, although not shown in the figures, a control unit is built into the base 24, and as its operation unit, a numeric keypad, power switch, display, etc. are provided on the front portion 24a of the base 24, and setting input is provided. In addition to controlling temperature, air supply/exhaust, and operating times of various parts as in the past, the operation and operating times of the moving device 22 are also controlled according to the program.

In the dental firing furnace configured in this way, several programs for a series of steps are set and input in advance, and the necessary ones are called up and used. For example, the operation is as follows.

(a) When the porcelain tooth 29a coated with porcelain is placed on the firing table 2Oa and the program is specified and started from the state shown in FIG. The porcelain tooth 29a is heated by the heater inside, preheating,
Each process of drying and firing is performed. During this time, the height position of the furnace body 21 is sequentially changed by controlling the lifting device 33 according to the program. Until the firing of the porcelain tooth 29a is completed, the worker applies the porcelain tooth 29b on the firing table 2ob.
(Z is placed in the standby state and a necessary program is specified for the porcelain tooth 29b.

(b) When the firing of the porcelain tooth 29a is completed, the furnace body 21 is raised to the top by the lifting device 33, and then the furnace body 21 is moved together with the pillar 35 by the horizontal moving device, and the firing table 20 is moved.
1). Then, according to the program, the furnace body 21 is lowered to fire the porcelain tooth 29b. Furnace body 21
moved onto the firing table 201), causing the porcelain tooth 29a to
is in a state where it does not receive radiant heat from the furnace body 21, and is rapidly cooled to room temperature. Then, while the porcelain tooth 13 is being fired, the firing table 2Oa side is placed in a standby state and the program necessary for firing is specified. (0) When the firing of the porcelain tooth 29b is completed, the furnace body 21 The device moves to the stand 2Oa side and fires the object to be fired thereon according to the designated program.

The first embodiment above shows the one with two firing tables, but
Depending on the case, three or more furnace bodies may be provided and each furnace body may be appropriately combined to perform firing.

Further, in the first embodiment, the moving device was provided so that the furnace body moved up and down and moved horizontally, but the furnace body moved down and down in a fixed position, and each of the firing tables moved horizontally together with one base. The horizontal movement is not limited to being along a straight line, but may also be a configuration in which it turns in a horizontal plane. For example, by rotating one base supporting the firing table, the firing table below the furnace body can be replaced. Further, the furnace body may be fixed in a fixed position so that the base can also move up and down. Furthermore, both the firing table and the furnace body may be able to move up and down and horizontally.

<Effects of the Invention> Since the dental firing furnace of the present invention uses one furnace body in combination with each of a plurality of firing tables using a moving device, it is possible to use a firing table that is not used in combination with a furnace body. The object to be fired next can be placed on the table and placed in a standby state, and after completion of firing on one firing table, firing can be started on another firing table, thereby completing the firing. The firing table supporting the object is immediately removed from directly below the furnace body, and the fired object can be cooled well without the operator having to operate it immediately after completion of firing. Therefore,
This not only greatly improves firing efficiency, but also allows workers to take out the fired product from the firing table and replace it with another workpiece, allowing them to concentrate on other tasks such as applying porcelain. This has the great effect of automating the continuous operation from the completion of firing of the object to be fired to the start of the next firing, which was conventionally performed by an operator.

[Brief explanation of the drawing]

Fig. 1 is a front view of an embodiment of the invention, Fig. 2 is a plan view of the embodiment, Fig. 3 is a right side view of the embodiment, Fig. 4 is a rear view of the embodiment, and Fig. 5. 6 is a front view showing an example of a conventional dental firing furnace, and FIG. 6 is a right side view of the same conventional example. 20a120...e firing table, 21...furnace body, 22...
- Moving device, 29a, 291)...Object to be fired (porcelain tooth). Patent applicant Matsu Fudo Co., Ltd. Sansha Denki Seisakusho Representative Director Satoshi Shimizu and 2 others Iris 1 Figure 24a Figure 2 Iris 30 Toe 40 χ5 side Sono 6

Claims (1)

[Claims] (1) A plurality of firing tables on which objects to be fired are placed, a furnace body that opens downward and is formed in a size that can cover any of the firing tables, and one of the plurality of firing tables and the furnace body. Or, any one of the plurality of firing tables provided for both can be selected and moved between a state where it is located directly under the furnace body and a state where the selected one firing table is covered by the furnace body. 1. A dental kiln, comprising: a moving device configured as shown in FIG.