JP2010005869A - Compression molding apparatus for ceramic granulated body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compression molding apparatus for ceramic granulated bodies which can control product fluctuation every molding shot even in the case where humidity and temperature of the installation site are not manageable. <P>SOLUTION: This compression molding apparatus for ceramic granulated bodies is equipped with a compression molding machine body 10 for compressing ceramic granulated bodies 100 filling a molding die 2 by way of a first plunger 3 and a second plunger 4 inserted from the both ends of the molding die 2, a filling device 20 for filling the ceramic granulated bodies 100 into the molding die 2 of the compression molding machine body 10, and a feeding hopper 30; where a moisture content sensor 21 for measuring moisture content W<SB>x</SB>of the ceramic granulated bodies 100 and a temperature sensor 22 for measuring temperature T<SB>x</SB>are provided in the filling device 20; a pressure sensor 5 for measuring pressure Px generated at the time of compression molding is provided to the compression molding machine body 10; and a controlling means 40 is provided for correcting compression peak pressure and/or compression interval based on the moisture content W<SB>x</SB>and/or temperature T<SB>x</SB>. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a compression molding apparatus for a ceramic granule for compressing and molding a ceramic granule obtained by granulating a mixture containing ceramic powder and a resin binder.

  A compression molding method is known as a method for molding a ceramic molded body. As a molding material used in such a compression molding method, for example, a ceramic granule obtained by granulating a mixture containing ceramic powder and a resin binder as described in Patent Document 1 is used. It has been. By solidifying the ceramic powder with a resin binder, powder feeding fluidity and press adhesiveness can be imparted to the ceramic molding material.

When a ceramic granule is compression-molded by a compression molding apparatus, when the compression end point of compression molding is controlled by a pressure peak, there is a problem that length variation occurs for each shot when a rod-shaped ingot is formed. . Further, when the compression end point is controlled by the interval between the upper punch and the lower punch, there is a problem in that the density of the obtained ingot varies.
JP 2000-327431 A

  The present inventors consider that the cause of variations in length and density for each molding shot as described above is due to the viscoelasticity of the resin binder. Specifically, since the viscoelasticity of the resin binder changes due to changes in the moisture content and temperature, the fluidity and temperature of the material supplied for each molding shot vary, so that the filling fluidity of the ceramic granule can be reduced. We believe that the compressibility varies from molding shot to molding shot. For example, when the compression end point of molding is controlled by pressure, even if compression is performed until the same pressure is reached, if the ceramic granulated body has high rigidity, it is not compressed sufficiently, as shown in FIG. 9 (a). When the ceramic ingot 80a is formed with a relatively long ingot 80a and the rigidity of the ceramic granule is low, the ingot 80b is compressed so that a relatively short ingot 80b is obtained as shown in FIG. 9B. In addition, for example, when controlling by the distance between punches of the mold at the end point of molding, an ingot having a low molded body density is difficult to compress when the ceramic granulated body has high rigidity even when compressed at the same interval. When the ceramic granulated body is low in rigidity, it becomes easy to be compressed, so that an ingot having a high compact density is formed.

  In order to suppress product variations due to variations in the moisture content and temperature of the material supplied for each molding shot, it is also possible to perform compression molding by installing a compression molding machine in a place where temperature and humidity are controlled. Conceivable. However, in the case of factory production in which a large number of compression molding machines are juxtaposed to perform mass production, providing a sufficiently environmentally controlled place may adversely affect production costs.

  The present invention provides a compression molding apparatus for a ceramic granule that can suppress variations in product length and density for each molding shot even when the humidity and temperature of the place where the compression molding machine is installed cannot be precisely controlled. The purpose is to provide.

In order to solve the above-mentioned problems, the compression molding apparatus for a ceramic granule according to the present invention is a ceramic granulation filled in a die by a first punch and a second punch inserted from both ends of the die. A compression molding machine main body for compressing the body, a filler for filling the ceramic granule in a mold die of the compression molding machine main body, and for supplying the ceramic granulation body to the filler comprising a supply hopper, the said the filling instrument, for measuring the temperature T _X of the moisture content sensor and the storage ceramic granulated body for measuring the water content W _X storage ceramic granulate A temperature sensor is provided, and the compression molding machine main body is further provided with a pressure sensor for measuring the pressure Px generated in the first punch and the second punch during the compression molding, and the measured moisture content Based on the W _X and / or the temperature T _X, the compression peak pressure of the first punch and the second punch and / or, in which comprises a control means so as to correct the compression interval. A ceramic granule obtained by granulating a mixture containing ceramic powder and a resin binder (hereinafter also simply referred to as a ceramic granule) contains a resin binder, and therefore has an elastic modulus depending on the water content and temperature. Is easy to change. According to the present invention, the moisture content W _X and / or the temperature T _X immediately before compression is measured _, and the molding conditions for each shot are finely determined based on the obtained moisture content W _X and / or the temperature T _X. In order to adjust, when pressure control is performed on the compression end point, variation in length can be suppressed for each shot, and when the compression end point is controlled by an interval between the upper punch and the lower punch, Density variation can be suppressed. That is, by measuring the moisture content W _X and / or the temperature T _X of the ceramic granulated body in advance and using the values for correction of the compression conditions, it is used for feedforward control to obtain a compact with less variation. Can do.

In the compression molding apparatus for a ceramic granule, the compression end point of the ceramic granule by the first punch and the second punch in the main body of the compression molding machine is a reference compression peak pressure P ₀ applied to the first punch and the second punch. Is corrected to reduce the reference compression peak pressure P ₀ by a predetermined pressure when the moisture content W _X is higher than a predetermined optimum moisture content W _0. It is preferable to provide a control means for correcting the reference compression peak pressure P ₀ by a predetermined pressure when it is lower than the predetermined optimum water content W ₀ .

Further, in the above-described ceramic granulated-body compression molding apparatus, the compression end point of the compression molding machine granulated ceramic by the first punch and second punch of the body is a reference interval L ₀ of the first punch and second punch When the position is controlled, when the moisture content W _X is lower than the predetermined optimum moisture content W ₀ , the reference interval L ₀ is corrected to be narrowed by a predetermined amount, and the preset optimum moisture content is determined. When the rate is higher than the rate W _0, it is preferable to provide a control unit that corrects the reference interval L ₀ by a predetermined amount.

  According to the present invention, it is possible to suppress variations in length and density between shots when a plurality of shots of ceramic granulates are continuously compression-molded.

  The compression molding apparatus for ceramic granules according to the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram schematically showing the configuration of a compression molding apparatus for a ceramic granule according to this embodiment.

  In FIG. 1, reference numeral 10 denotes a compression molding machine body for compressing a ceramic granulated body having a die 2, a first punch 3, and a second punch 4, and 20 denotes a mold for the compression molding machine body 10. It is a filling machine which is a powder box which fills the die 2 with the ceramic granulated body 100, 30 is a supply hopper for supplying the ceramic granulated body to the filler 20, 40 is a control unit, 41 is a storage unit, 42 is It is a molding condition setting unit. The first punch 3 and the second punch 4 are further provided with a pressure sensor 5 for measuring the pressure Px generated in the first punch 3 and the second punch 4 during compression molding. The filler 20 and the supply hopper 30 are connected by a supply path 31.

FIG. 2 is an enlarged schematic view of the filling device 20. The filler 20 is a device that fills the die 2 by moving the ceramic granule 100 supplied from the supply hopper 30 in the direction of the white arrow. The filler 20, moisture content sensors 21 for measuring housed moisture content W _X ceramic Zotsubutai 100, a temperature sensor 22 for measuring the temperature T _X storage ceramic granulate comprising And is connected to the control unit 40 through the storage unit 41.

The storage unit 41 functionally has a general setting condition of the compression molding apparatus, a moisture content W _X measured by the moisture sensor 21, a temperature T _X measured by the temperature sensor 22, and a pressure measured by the pressure sensor 5. A device that stores Px and the like, and includes a volatile storage element such as a RAM (Random Access Memory). Further, the control unit 40 includes, for example, a microprocessor, a storage element, its peripheral circuit, and the like, and functionally sets the general moisture content W _X stored in the storage unit 41 and the general setting conditions of the compression molding apparatus. An arithmetic processing unit (not shown) performs arithmetic processing based on the temperature T _X and pressure Px data, and controls the compression molding process according to set conditions. Note that specific modes of the control unit 40 and the storage unit 41 are not particularly limited in the present invention. In the present embodiment, in particular, the moisture content measured by the water content sensor 21 W _X, the temperature T _X measured by the temperature sensor 22 is stored, the stored water content W _X, based on the temperature T _X, As will be described in detail later, a correction value for correcting fine adjustment of the reference compression peak pressure P ₀ and the reference interval L ₀ between the first punch and the second punch is calculated, and the compression peak corrected by the correction value is calculated. in pressure P _a and the press distance L _a, respectively control according to each part of the ceramic granulated-body compression molding apparatus to the function in accordance with prestored control program in the storage device.

  As the control of the compression molding process, for example, the supply amount of the ceramic granulated body 100 from the supply hopper 30 to the filler 20 is adjusted by comparing the set supply amount and the actual supply amount by a supply amount control unit (not shown). Or the filling timing of the ceramic granule 100 into the die 2 by the filling device 20, the movable timing of the first punch 3 and the second punch 4 in the compression molding machine main body 10, the die 2 and the second punch 4 Control of the filling amount specified in is performed.

In the compression molding apparatus for a ceramic granule having such a configuration, first, the operator of the compression molding apparatus uses the reference pressure peak P ₀ or the first punch for specifying the end point of the compression molding from the molding condition setting unit 42 and the first punch. The reference interval L ₀ of the second punch, the filling amount M of the ceramic granule per shot, the mold temperature, etc. are set together with the allowable variation range and the like. At this time, if a specific set value exceeds an allowable range, a command for issuing an alarm or issuing a movable stop command can also be set.

  And the compression molding apparatus for ceramic granulation bodies is operated. At the beginning of the operation of the compression molding apparatus for ceramic granules, the ceramic granules 100 are supplied from the supply hopper 30 to the filler 20. On the other hand, after the ceramic granulated body 100 is supplied to the filler 20 or before and after the supply, in the compression molding machine main body 10, the second punch 4 is moved by a predetermined distance, and the die 2 and the second punch 4 are moved. Thus, a mold cavity for filling the ceramic granule 100 having a set filling amount composed of the space formed by the above is formed. Then, a signal for transmitting that the mold cavity is formed from the compression molding machine main body 10 is transmitted to the control unit 40. After detecting the signal, the control unit 40 issues a command for filling the mold granule 100 with the ceramic granulated body 100 to the filler 20, and as shown in FIGS. 3 (a) and 3 (b), The filler 20 is moved to fill the mold die 2 with the ceramic granulated body 100. Then, after filling, as shown in FIG. 3C, a command to perform compression molding is issued to the first punch 3 and the second punch 4 of the compression molding machine body 10.

FIG. 4 is a flowchart showing a series of compression molding processes in the ceramic granule compression molding apparatus of the present embodiment. In FIG. 4, when various setting conditions are input from the molding condition setting unit 42 (S 1) and a molding process start command is input (S 2), first, the ceramic granule is supplied from the supply hopper 30 to the filler 20. 100 is supplied (S3). Then, the moisture content W _X of the ceramic granule 100 supplied to the filler 20 is measured by the moisture sensor 21 and the temperature T _X is measured by the temperature sensor 22 (S4). Then, the storage unit 41 stores the measured moisture content W _X and temperature T _X and transmits the stored data to the control unit 40. Next, an unillustrated arithmetic means provided in the control unit 40, based on the measured moisture content W and the temperature T _X, corrected compression peak pressure P _A, or, according to the first punch 3 and the second punch 4 _A correction interval LA that corrects the compression interval of the ceramic granulated body 100 is calculated (S5). Then, based on the obtained correction value, the end point setting for generating the compression end point signal is corrected (S6). At almost the same time, the ceramic granule 100 is filled from the filler 20 into the mold cavity formed by the mold die 2 and the second punch 4 (S7). Then, after temporary compression by the first punch 3, it is confirmed that a predetermined amount of the ceramic granulated body 100 is filled, and then the first punch 3 and the second punch 4 are moved to move the ceramic granulated body 100. Is compressed (S8). Then, the pressure sensor provided in the mold compression progresses reaches the corrected compression peak pressure P _A, or that the position sensor first punch 3 and the second punch 4 reaches the correct distance L _A Is confirmed, a compression end point signal is transmitted to the control unit 40. Then, at the same time when the control unit 40 receives the compression end point signal, a mold opening command is issued to the first punch 3 and the second punch 4 to complete the compression (S9). Then, the obtained compression molded body is ejected and released (S10). This is the one-shot cycle of compression molding. Then, steps S3 to S10 are repeated for a predetermined number of shots.

  Next, a correction method used in the above process will be described.

The compression molding end point in the compression molding is generally (i) pressure control with a reference compression peak pressure P ₀ applied to the first punch and the second punch as a set value, or (ii) the first punch and the second punch. Is controlled by position control using the reference interval L ₀ as a set value.

(I) The pressure control using the reference compression peak pressure P ₀ applied to the first punch and the second punch as a set value is performed after the ceramic granule 100 is filled in the die 2 and then the first punch 3 and the second punch. 4, the ceramic granulated body 100 is compressed, and when the pressure applied to the first punch 3 and the second punch 4 reaches a predetermined reference compression peak pressure P ₀ , the compression is stopped, or the compression is performed by switching to the holding pressure. Is to end.

In this case, the water content W _X of the measured granulated ceramic just before compression, low correction compression peak pressure than the basic compression peak pressure P ₀ in the case higher than the optimum water content W ₀ predetermined by compressing until P _A1, it is possible to prevent the ingot becomes too short by too compressed. On the other hand, when the moisture content is lower than the predetermined optimum water content W ₀ , the compression is performed until the compression peak pressure P _A1 is higher than the reference compression peak pressure P ₀ , thereby suppressing the ingot from becoming too long due to insufficient compression. can do.

  Examples of the correction value that can be adopted at this time include a correction value using a coefficient obtained as follows.

Previously measures a plurality of points pressing pressure P _X relative to the water content W _X when the compression molding ceramic Zotsubutai 100, the horizontal axis the moisture content W of the granulated ceramic, compression molding the ceramic granular material The press pressure P with respect to the moisture content W is plotted on the vertical axis, and an approximate curve connecting them is obtained. An example of the approximate curve obtained at this time is shown in FIG.

In FIG. 5, the slope of the tangent to the approximate curve when the reference moisture content W ₀ is set in advance is A1. On the other hand, when the moisture content measured in a certain shot is W _X1 (<W ₀ ), the slope of the tangent to the approximate curve when the moisture content is W _X1 is B1 ₊ . Then, α ₊ = A1 / B1 ₊ is calculated. Or, if the water content measured at certain shot of W _{X2 (>} W _0), the tangent slope for the approximate curve when the water content W _X2 B1 _- to. Then, α ₋ = A1 / B1 ₋ is calculated. This coefficient α ₊ or α ₋ (hereinafter collectively referred to as α) is based on the reference compression peak pressure P ₀ set as the optimum value at the reference moisture content W ₀ when the moisture content is W _X. is for calculating an optimum press pressure _{P A1} of, specifically, on the basis of the reference compressed peak pressure _{P 0} at the time of the reference water content _{W 0 P A1 = P 0 /} α ··· (1 ) To calculate the corrected compression peak pressure P _A1 , the press pressure can be corrected to the optimum press pressure at the granule moisture content during press molding. According to the corrected compression peak pressure P _A1 calculated in this way, an appropriate pressure for suppressing length variation between shots can be obtained.

Similarly, in advance, the pressing pressure P _X relative to the temperature T _X when the compression molding of ceramic granular material was measured a plurality of points, on the horizontal axis the temperature T of the granulated ceramic, compression molding the ceramic granular material The press pressure P with respect to the temperature T is plotted on the vertical axis, and an approximate curve connecting them is obtained. An example of the approximate curve obtained at this time is shown in FIG.

In FIG. 6, the slope of the tangent to the approximate curve at a preset reference temperature T ₀ is A2. On the other hand, when the temperature measured in a certain shot is T _X1 (<T ₀ ), the slope of the tangent to the approximate curve when the temperature is T _X1 is B2 ₊ . Then, β ₊ = A2 / B2 ₊ is calculated. Alternatively, when the temperature measured in a certain shot is T _X2 (> T ₀ ), the slope of the tangent to the approximate curve when the temperature is T _X2 is B2 ₋ . Then, β ₋ = A2 / B2 ₋ is calculated. This coefficient β ₊ or β ₋ (hereinafter collectively referred to as β) is the optimum at the temperature T _X based on the reference compression peak pressure P ₀ set as the optimum value at the reference temperature T _0. is intended to calculate the press-pressure _{P A1,} specifically, on the basis of the reference compressed peak pressure _{P 0} at a reference temperature _{T 0,} the _{P A1 = P 0 / α ···} (1) Further, the pressure pressure is press-molded by calculating the corrected compression peak pressure P _A2 by the formula of P _A2 = P ₀ / α · β (2) further incorporating the temperature coefficient β It is possible to correct to the optimum pressing pressure at the granule moisture content and granule temperature. According to the corrected compression peak pressure _PA2 calculated in this way, a more appropriate pressure for suppressing length variation between shots can be obtained.

(Ii) Position control using the reference interval L ₀ of the first punch 3 and the second punch 4 as a set value is performed by the first punch 3 and the second punch 4 after the ceramic granule 100 is filled in the die 2. compressing the ceramic Zotsubutai 100, if the distance between the first punch 3 and the second punch 4 reaches a predetermined reference distance L _0, to stop the compression, or is that switched to the holding pressure.

In this case, when the moisture content W _X of the ceramic granule 100 measured immediately before compression is lower than the predetermined optimum moisture content W _{0, the} correction interval is narrower by a predetermined amount than the reference interval L _0. By compressing until L _A1 , it is possible to suppress a decrease in ingot density due to insufficient compression. On the other hand, if the moisture content is higher than the predetermined optimum water content W _{0, the} ingot density becomes too high due to over-compression by compressing until a correction interval LA ₁ wider than the reference interval L ₀ by a predetermined amount. This can be suppressed.

  Examples of the correction value that can be adopted at this time include a correction value using a coefficient obtained as follows.

Previously, in a manner similar to that described above (i), the pressing pressure P _X measures a plurality of points for moisture content W _X when the compression molding of ceramic granular material, the water content W of the granulated ceramic On the horizontal axis, the press pressure P against the water content W when the ceramic granule is compression-molded is plotted on the vertical axis, and an approximate curve as shown in FIG. 5 is obtained. In the same manner as described in (i) above, the tangent slope A1 and the tangential slope B1 are obtained from the approximate curve in FIG. 5, and α ₊ = A1 / B1 ₊ or α ₋ = A1 / B1 ₋ is obtained. calculate. And
L _A1 = L ₀ · α (3) (α is α ₊ or α ₋ )
By calculating the corrected correction interval L _{A1 according} to the formula, the interval between the first punch and the second punch can be corrected to an interval at which the optimum compression peak pressure can be obtained in the granule moisture content during press molding. it can. According to the corrected correction interval L _A1 calculated in this way, an appropriate compression interval for suppressing variation in density between shots can be obtained.

Similarly, in advance, in a manner similar to that described above (i), the pressing pressure P _X relative to the temperature T _X when the compression molding ceramic Zotsubutai 100 multiple point measurement, the temperature of the granulated ceramic The horizontal axis is plotted on the horizontal axis, and the press pressure P against the temperature T when the ceramic granule is compression molded is plotted on the vertical axis, and an approximate curve as shown in FIG. 6 is obtained. Then, in the same manner as described in (i) above, the tangential slope A2 and the tangential slope B2 are obtained from the approximate curve in FIG. 6, and β ₊ = A2 / B2 ₊ or β ₋ = A2 / B2 ₋ Is calculated. Then, a temperature coefficient β (β is B2 ₊ or β ₋ ) is further incorporated into the formula of L _A1 = L ₀ · α (3).
L _A2 = L ₀ · α · β (4)
By calculating the correction interval L _A2 by the following equation, the correction interval L can be corrected to an interval at which the optimum compression peak pressure can be obtained at the granule moisture content and granule temperature during press molding. According to the correction interval L _A2 calculated in this way, a more appropriate pressure for suppressing variation in density between shots can be obtained.

  Moreover, as other embodiment of the compression molding apparatus for ceramic granulation bodies of this embodiment, as shown in FIG. 7, the moisture content of the ceramic granulation body accommodated in the filler 20 and the supply hopper 30 is shown. A humidity control device 50 having a humidifying and dehumidifying function for adjusting the humidity may be provided. In FIG. 7, 51 is an air passage for blowing air conditioned in order to condition the filling device 20, and 52 is an air flow for blowing air conditioned in order to condition the supply hopper 30. A path, 53 and 54 are meshes, and 55 is a ceramic granule supply port. A ventilation path 51 and a ventilation path 52 are connected to the humidity control apparatus 50, and air conditioned by the humidity control apparatus 50 is blown from the ventilation paths 51 and 52 to the filling device 20 and the supply hopper 30. Thus, the humidity of the ceramic granule can be adjusted. According to such a humidity control apparatus 50, the moisture content of the ceramic granulated body 100 supplied to the compression molding machine main body 10 can be controlled. As the humidity control device 50, an air conditioner device that blows air with controlled humidity is used.

Further, when the ceramic granulated-body compression molding apparatus of the present invention, a particular n shot pressure peaks P _x which is Keigawa during compression molding is deviated from the setting pressure P _S aim, By increasing / decreasing the amount of the ceramic granule filled in the next shot (n + 1) shot, the maximum pressure value in the compression molding of the (n + 1) shot is the target set pressure. it is preferred to control such approaches P _S is, specifically when, Keigawa pressure peak P _x during compression molding of the n shot is, the predetermined set lower than the pressure P _S to increase the amount of granulated ceramic filled in the next cycle (n + 1) shot compression molding cycle, the predetermined set pressure P _S next cycle is higher than the (n + 1) Sera filled in the compression molding cycle of the shot It is preferable to provide a control means for performing correction so as to reduce the amount of the mic granulated body. According to this control unit, before based on the actual pressure peak P _x which is measured in cycles, to the filling amount of granulated ceramic of the next cycle can be finely adjusted, the compression molding in the next cycle The peak pressure can be adjusted, thereby suppressing variations in the density of the molded body between shots.

As the filling amount M _{n + 1} of the ceramic granule filled in the compression molding cycle of the (n + 1) th shot (n is an integer of 1 or more), Equation (5): M _{n + 1} = M _n ± R ₀ · α · β. (5)
(In the formula (5), M _n is the filling amount of the ceramic granule of the nth shot, R ₀ is the reference powder filling correction amount, α is the water content of the ceramic granule on the horizontal axis, When the pressing pressure P against the water content W when the ceramic granule is compression-molded is plotted on the vertical axis, the slope of the tangent at the reference water content W ₀ is A1 and the water content W _X from the approximate curve connecting them. Is a coefficient calculated using α = A1 / B1, where β is the temperature when the ceramic granule is compression molded with the temperature T of the ceramic granule as the horizontal axis. When the pressing pressure P with respect to the temperature T is plotted on the vertical axis, the slope of the tangent at the reference temperature T ₀ is A2 and the slope of the tangent at the temperature T _X is B2 from the approximate curve connecting them. (The coefficient is calculated using A2 / B2) Method is exemplified.

As shown in FIG. 8, the correction formula (5) is an optimum standard when the moisture content W _X of the ceramic granule measured immediately before compression is higher than a predetermined optimum moisture content W _0. By increasing the correction filling amount by a predetermined amount larger than the filling correction amount _R0, it is possible to reach the target press pressure with a smaller number of shots. On the other hand, when it is lower than the predetermined optimum water content W _{0, the} possibility of passing the target press pressure is reduced by reducing the correction filling amount by a predetermined amount less than the reference filling correction amount R _0. Can do. Furthermore, when the temperature T _X when the ceramic granule is compression-molded is higher than a predetermined reference temperature T _{0, the} correction filling amount is larger by a predetermined amount than the reference filling correction amount R _0. By increasing, the target press pressure can be reached with a smaller number of shots. On the other hand, when the temperature is lower than a predetermined reference temperature T _{0, the} possibility of passing the target press pressure is reduced by reducing the filling correction amount by a predetermined amount less than the reference filling correction amount R _0. Can do.

The filling amount M _{n + 1} of the (n + 1) -th shot ceramic granule calculated in this way provides an appropriate filling amount for suppressing variation in length and variation in density between shots.

  The above-described compression molding apparatus for a ceramic granulated body according to the present invention can be used without particular limitation as long as it is an application that requires compression molding of the ceramic granulated body. It is preferably used as a compression molding apparatus for pre-forming for obtaining.

  The ceramic granulated body is obtained by granulating a mixture containing ceramic powder and a resin binder by a known granulation method.

  Specific examples of the ceramic powder include metal oxide ceramic powders such as alumina, zirconia, and ferrite, non-oxide ceramic powders such as silicon carbide and silicon nitride, barium titanate, titanium / zirconate, and these. And ceramic powders such as these composite compounds. These ceramic powders may be used alone or in combination of two or more. The particle size of the ceramic powder is preferably in the range of about 0.5 to 5 μm, preferably about 0.7 to 3 μm.

  On the other hand, specific examples of the resin binder include, for example, partially saponified products of polyvinyl alcohol and polyvinyl acetate, and homopolymers such as poly (meth) acrylic acid, methylcellulose, and acrylamides. These may be used alone or in combination of two or more.

  Specific examples of the blending ratio of the binder include, for example, 0.2 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, particularly 0.7 to 3 parts by weight with respect to 100 parts by weight of the ceramic powder. It is preferable that

  In addition, you may add additives, such as a dispersing agent, a plasticizer, a mold release agent, to a ceramic granule further as needed according to the objective. Moreover, as a ceramic granulation body, what combined 2 or more types of ceramic granulation bodies which consist of a different ceramic powder may be sufficient.

  The particle size of the ceramic granule suitable for compression molding is preferably in the range of about 20 to 300 μm, preferably about 30 to 100 μm. The moisture content is preferably in the range of 0.5 to 0.8%. If the moisture content is too low, the strength of the resulting molded product tends to decrease and the occurrence rate of cracks tends to increase, and if it is too high, the material adherence to the mold increases and the molded product There is a risk of unevenness in the surface and an increase in the occurrence rate of cracks.

FIG. 1 is a schematic configuration diagram schematically showing the configuration of a compression molding apparatus for a ceramic granule according to this embodiment. FIG. 2 is an enlarged schematic view of the filling device 20 in FIG. 3A to 3C are explanatory diagrams for explaining the compression molding process. FIG. 4 is a flowchart for explaining a series of compression molding processes in the ceramic granule compression molding apparatus of the present embodiment. The water content W _X of granulated ceramic on the horizontal axis, is plotted on the vertical axis the press pressure P _X for the hydrous ratio W _X when the compression molding the ceramic granular material, by subtracting the approximate curve connecting it A graph of when. The temperature T _X when the compression molding of ceramic granular material on the horizontal axis, is plotted on the vertical axis the press pressure P _X for the temperature T _X when the compression molding the ceramic granular material, the approximation curve connecting it The graph when subtracting is shown. FIG. 7 is a schematic configuration diagram for explaining a humidity control apparatus provided in the ceramic granule compression molding apparatus of the present embodiment. FIG. 8 is a graph when the horizontal axis represents the difference between the set pressing pressure and the actual pressure, and the vertical axis represents the filling correction amount of the ceramic granule for correcting the difference in the pressing pressure. FIG. 9 is an explanatory diagram for explaining variations in the length of an ingot obtained when the compression end point of molding is controlled by pressure in a conventional compression molding machine.

Explanation of symbols

2 Mold Dies 3 First Punch 4 Second Punch 5 Pressure Sensor 10 Compression Molding Machine Main Body 20 Filler 21 Moisture Sensor 22 Temperature Sensor 30 Supply Hopper 31 Supply Channel 40 Control Unit 40a Calculation Unit 41 Storage Unit 42 Molding Condition Setting Unit DESCRIPTION OF SYMBOLS 50 Humidity control apparatus 51,52 Air flow path 53,54 Mesh 55 Ceramic granule supply port 80a, 80b Ingot 100 Ceramic granule

Claims (13)

A ceramic granule compression molding apparatus for compression molding a ceramic granule obtained by granulating a mixture containing a ceramic powder and a resin binder,
A compression molding machine main body for compressing the ceramic granule filled in the mold die by the first punch and the second punch inserted from both ends of the mold die;
A filler for filling a ceramic granule in a die of the compression molding machine main body;
A supply hopper for supplying a ceramic granulated body to the filler,
Wherein the filler has a temperature sensor provided for measuring the temperature T _X of the moisture content sensor and the storage ceramic granulated body for measuring the water content W _X storage ceramic granulate ,
The compression molding machine main body further includes a pressure sensor for measuring the pressure Px generated in the first punch and the second punch during compression molding,
Control means for correcting the compression peak pressure and / or the compression interval of the first punch and the second punch based on the measured water content W _X and / or temperature T _X is provided. A compression molding apparatus for ceramic granules. The compression end point of the ceramic granulated body by the first punch and the second punch in the compression molding machine main body is subjected to pressure control with a reference compression peak pressure P ₀ applied to the first punch and the second punch as a set value,
When the water content W _X is higher than the predetermined optimum water content W ₀ , the reference compression peak pressure P ₀ is corrected to be reduced by a predetermined pressure, and is lower than the predetermined optimum water content W _0. ceramic granulated-body compression molding apparatus according to claim 1, further comprising a control means such that the correction to increase the reference compressed peak pressure P ₀ by a predetermined pressure in the case. The corrected compression peak pressure _PA1 is expressed by the following formula (1):
P _A1 = P ₀ / α (1)
(In the formula (1), α plots the water content W of the ceramic granule on the horizontal axis and the press pressure P against the water content W when the ceramic granule is compression-molded on the vertical axis, From the approximate curve connecting them, when the slope of the tangent at the reference moisture content W ₀ is A1, and the slope of the tangent at the moisture content W _X is B1, this is a coefficient calculated using α = A1 / B1. )
The compression molding apparatus for a ceramic granulated body according to claim 2, which is obtained by: When the temperature T _X is higher than the predetermined optimum temperature T _0, correction is made to lower the reference compression peak pressure P ₀ by a predetermined pressure, and the temperature T _X is higher than the predetermined optimum temperature T _0. ceramic granulated-body compression molding apparatus according to claim 2, further comprising a control means such that the correction to increase the reference compressed peak pressure P ₀ by a predetermined pressure if it is lower. The corrected compression peak pressure _PA2 is expressed by the following formula (2):
P _A2 = P ₀ / α · β (2)
(In the formula (2), α plots the water content W of the ceramic granule on the horizontal axis and the press pressure P against the water content W when the ceramic granule is compression-molded on the vertical axis, A coefficient calculated using α = A1 / B1 when the slope of the tangent at the reference moisture content W ₀ is A1, and the slope of the tangent at the moisture content W _X is B1, Plots the temperature T of the ceramic granulated body on the horizontal axis and the press pressure P against the temperature T when the ceramic granulated body is compression-molded on the vertical axis, and from the approximate curve connecting them, the reference temperature T ₀ the inclination of a tangent line at A2, when the tangent slope at the temperature T _X was B2, a coefficient calculated using β = A2 / B2)
The compression molding apparatus for a ceramic granulated body according to claim 4, which is obtained by: The compression end point of the ceramic granulated body by the first punch and the second punch in the compression molding machine main body is position-controlled using a reference interval L ₀ between the first punch and the second punch as a set value,
When the water content W _X is lower than the predetermined optimum water content W ₀ , the reference interval L ₀ is corrected to be narrowed by a predetermined amount, and when the water content W _X is higher than the predetermined optimum water content W _0. ceramic granulated-body compression molding apparatus according to claim 1, further comprising a control means such that the correction to widen the reference interval L ₀ by a predetermined amount is. The corrected interval L _A1 is expressed by the following formula (3):
L _A1 = L ₀ · α (3)
(In the formula (3), α plots the water content W of the ceramic granule on the horizontal axis and the press pressure P against the water content W when the ceramic granule is compression-molded on the vertical axis, From the approximate curve connecting them, when the slope of the tangent at the reference moisture content W ₀ is A1, and the slope of the tangent at the moisture content W _X is B1, this is a coefficient calculated using α = A1 / B1. )
The compression molding apparatus for a ceramic granulated body according to claim 6, which is obtained by: When the temperature T _X is lower than the predetermined optimum temperature T _0, correction is made to narrow the reference interval L ₀ by a predetermined amount, and the temperature T _X is higher than the predetermined optimum temperature T ₀ ceramic granulated-body compression molding apparatus according to claim 6, further comprising a control means such that the correction to widen the reference interval L ₀ by a predetermined amount to. The corrected distance L _A2 is expressed by the following formula (4):
L _A2 = L ₀ · α · β (4)
(In the formula (4), α plots the water content W of the ceramic granule on the horizontal axis and the press pressure P against the water content W when the ceramic granule is compression-molded on the vertical axis, A coefficient calculated using α = A1 / B1 when the slope of the tangent at the reference moisture content W ₀ is A1, and the slope of the tangent at the moisture content W _X is B1, Plots the temperature T of the ceramic granulated body on the horizontal axis and the press pressure P against the temperature T when the ceramic granulated body is compression-molded on the vertical axis, and from the approximate curve connecting them, the reference temperature T ₀ the inclination of a tangent line at A2, when the tangent slope at the temperature T _X was B2, a coefficient calculated using β = A2 / B2)
The compression molding apparatus for a ceramic granulated body according to claim 8, which is obtained by: Based on the measured temperature T _X and the water content W _X, the feed hopper interior and / or the filler inside of the humidity control means for adjusting humidity so as to approach the reference temperature T ₀ and the reference water content W ₀ a is provided The compression molding apparatus for a ceramic granule according to any one of claims 1 to 9. The temperature T _X and the water content W _X is, when outside the predetermined range set in advance, the ceramic granulated-body compression molding according to any one of claims 1 to 10, comprising means for alarm alarm apparatus. Keigawa pressure peaks Px during the compression of granulated ceramic is lower than the predetermined set pressure P _S increases the amount of granulated ceramic filled in the compression molding cycle for the next cycle, the any one of claims 1 to 11 comprising a control means for the corrected as to reduce the amount of granulated ceramic are filled in a compression molding cycle for the next cycle is higher than the predetermined set pressure P _S The compression molding apparatus for ceramic granules as described in 1. The filling amount M _{n + 1 of the} ceramic granule filled in the compression molding cycle of the (n + 1) th shot (n is an integer of 1 or more) is expressed by the following formula (5):
M _{n + 1} = M _n ± R ₀ · α · β (5)
(In the formula (5), M _n is the filling amount of the ceramic granule of the nth shot, R ₀ is a reference powder filling correction amount, α is the water content W of the ceramic granule on the horizontal axis, The press pressure P against the moisture content W when the ceramic granule is compression-molded is plotted on the vertical axis, and from the approximate curve connecting them, the slope of the tangent at the reference moisture content W ₀ is A1, and the moisture content W _X is tangent slope when the B1 of time, coefficient calculated using alpha = A1 / B1, beta is the horizontal axis the temperature T _X of the ceramic granules were compression molded the ceramic granular material plotted on the ordinate the press pressure P _X for the temperature T _X when, from the approximate curve connecting it, the inclination of a tangent line at the reference temperature T ₀ A2, if the tangent slope at the temperature T _X was B2 Is a coefficient calculated using β = A2 / B2.)
The compression molding apparatus for a ceramic granule according to claim 12, which is controlled so as to become.

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