JP4042431B2 - Method for manufacturing ceramic laminate - Google Patents

Description

[0001]
【Technical field】
The present invention relates to a method for producing a ceramic laminate formed by laminating a plurality of ceramic layers.
[0002]
[Prior art]
In recent years, in order to obtain a high displacement at a low voltage, a piezoelectric actuator is provided with a thin piezoelectric ceramic having a thickness of generally 20 to 200 μm and a metal electrode (internal electrode) alternately, which is generally 50 to 700. It has a structure of stacking sheets.
As a method for producing such a laminate, in Japanese Translation of PCT International Publication No. 2000-5000925, the first laminate obtained by laminating and pre-pressing sheets is cut or punched and degreased, and then the laminate is further laminated and fired. It is stated.
[0003]
In the embodiment of the publication, a rectangular shape is described as the cutting shape. It was observed that, when actually punching with a square, the internal electrodes were extremely deformed at the corners and the distance between the internal electrodes became non-uniform.
The reason for this deformation is that the punching stress of the first laminate becomes non-uniform due to the fact that the first laminate as the punched body is simply thick and the viscoelastic properties of the internal electrode and the piezoelectric sheet are different. it is conceivable that.
[0004]
This deformation causes delamination (delamination) during degreasing and firing, and causes fluctuations in product characteristics because a uniform voltage is not applied. Therefore, it is necessary to delete the deformed portion somewhere after punching, for example, after firing. To delete, a lot of man-hours are required, and the deleted material is wasted.
Moreover, since this deformation has a correlation with the warpage of the workpiece, it is considered that if the warpage can be reduced, the deformation can also be reduced.
[0005]
On the other hand, in JP-A-8-162364, a first laminate is formed by cutting in a sheet state, laminating a plurality of sheets, and pressing. It is described that a plurality of sheets are further laminated and pressure-bonded on the first laminated body a plurality of times and laminated to the final number.
However, in the method according to this publication, since the sheet is already cut into small pieces, it is necessary to handle the sheets one by one when transporting the sheets for subsequent lamination, which requires a lot of time and the production efficiency is poor.
[0006]
[Problems to be solved]
The present invention has been made in view of such conventional problems, and suppresses deformation of the internal electrode layer without lowering the production efficiency when producing a ceramic laminate having a large number of laminations. An object of the present invention is to provide a manufacturing method capable of obtaining a highly reliable ceramic laminate.
[0007]
[Means for solving problems]
  The first invention is a method for producing a ceramic laminate comprising alternately laminated ceramic layers and internal electrode layers.
  A crimping step of laminating a wide ceramic sheet including a plurality of ceramic layers in the width direction, heating and pressing in the laminating direction to form a pre-laminated body;
  In the pre-laminated body, the inner angles of all the corners exceed 90 °Polygon shape or barrel shapeA unit cutting step of forming a unit body having a width dimension including one ceramic layer in the width direction by punching so as to have,
  A degreasing step of removing by heating 90% or more of the binder resin contained in the ceramic layer of the unit body;
  And a firing step of firing the unit body. (Claim 1)
[0008]
In the present invention, after preparing the pre-laminated body in the crimping step, it is cut into the plurality of unit bodies in the unit cutting step. At this time, the outer peripheral shape of the unit body is punched so as to have a polygonal shape in which the inner angles of all the corners exceed 90 ° or a smooth curved surface shape.
Therefore, there is almost no concentration of punching stress when punching in this unit cutting process. Therefore, a large deformation of the internal electrode layer can be prevented in the cut unit body. Therefore, even after the subsequent degreasing step and firing step, the occurrence of delamination and cracks due to the deformation of the internal electrode layer can be suppressed.
[0009]
In the unit cutting step, a pre-laminated body formed by previously laminating a plurality of ceramic sheets is cut. For this reason, the unit body can be handled in the unit of the number of laminated layers of the preliminary laminated body, and the production efficiency is not lowered as in the case of handling the ceramic layers one by one.
[0010]
Therefore, according to the present invention, it is possible to provide a manufacturing method capable of obtaining a highly reliable ceramic laminate by suppressing the deformation of the internal electrode layer without reducing the manufacturing efficiency.
As described above, the present invention is a method for producing a ceramic laminate in which ceramic layers and internal electrode layers are alternately laminated. This ceramic laminate has a portion in which ceramic layers are laminated. Needless to say, it is a concept including a case of being composed of parts.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
  In the first invention (invention 1), when punching out the preliminary laminate in the unit cutting step, as described above, a polygonal shape in which the inner angles of all the corners exceed 90 °, orBarrel shapePunched to have Here, the polygonal shape in which the inner angles of all the above-mentioned angles exceed 90 ° is a concept including a polygon that is a pentagon or more. Of these, octagons or more are particularly preferable..
[0014]
Moreover, between the said unit cutting process and the said degreasing | defatting process, the said unit body can be laminated | stacked two or more, and the secondary crimping | compression-bonding process which pressurizes in the lamination direction can be performed. In this case, by stacking a plurality of the unit bodies, a ceramic laminate having a relatively long laminate length can be obtained.
In the first aspect of the invention, it is of course possible to form a ceramic laminate with one unit body.
[0015]
  The punching shape in the unit cutting process is,An octagonal shape is preferred (claim 3). In this case, stress concentration at the time of punching in the unit cutting process can be more reliably suppressed.
[0016]
The thickness of the internal electrode layer is preferably in the range of 1/100 to 1/10 of the thickness of the ceramic layer. The thinner the internal electrode layer, the less influence on delamination and cracking. Therefore, the internal electrode layer is preferably 1/10 or less of the thickness of the ceramic layer. On the other hand, in order to stably secure the electrical characteristics of the internal electrode layer, the thickness is preferably 1/100 or more of the thickness of the ceramic layer.
[0017]
Further, the cutting in the unit cutting step may be performed within a range of −70 (° C.) to G (° C.), where G (° C.) is the glass transition point of the resin component contained in the ceramic layer. Preferred (claim 5). In the unit cutting step, a preliminary laminate formed by laminating a plurality of ceramic sheets as described above is punched out. In order to improve the punchability, it is effective to increase the elastic modulus of the ceramic sheet. For this purpose, it is effective to lower the temperature of the preliminary laminated body. Therefore, it is preferable to set the temperature to be equal to or lower than the glass transition point G (° C.) of the resin component contained in the ceramic layer, that is, the ceramic sheet. On the other hand, if the temperature of the preliminary laminate is too low, frost easily forms on the surface depending on the atmosphere. The presence of frost has an adverse effect such as the generation of bubbles in the subsequent degreasing process, firing process and the like. Therefore, the temperature of the preliminary laminate is preferably −70 ° C. or higher, and more preferably −30 ° C. or higher.
[0018]
The ceramic laminate is preferably a ceramic laminate for a piezoelectric actuator. When used in a piezo actuator, the ceramic layer is made thinner, the number of layers is increased, and a shape with a large aspect ratio is adopted. Therefore, in this case, since the delamination and cracks are particularly likely to occur, it is effective to employ the above manufacturing method.
[0019]
  The unit cutting step includes a die having a punch having a tip surface having a desired shape, and a punching hole that can be inserted into the punch while maintaining a predetermined clearance.BecauseIn addition, at least one of the punch and the die has a protrusion along the cut shape.Before the shearing by the punch and the die, the notch by the protrusion is provided.(Claim 7). In this case, before performing the shearing by the punch and the die, it is possible to provide the notch by the protruding portion, and the shearing by the punch and the die can be smoothly performed. Therefore, deformation of the ceramic layer and the internal electrode layer due to shear stress can be further suppressed.
[0020]
  Also, the aboveUnit cutting processIs provided with a punch having a tip surface of a desired shape, a die having a punching hole that can be inserted into the punch while maintaining a predetermined clearance, and arranged on the outer periphery of the punch so as to be movable forward and backward. A stripper having a protrusion at the tip is used, and the stripper is advanced with respect to the preliminary laminate placed on the die to pierce the protrusion halfway through the preliminary laminate. It is also possible to form the unit body by providing a notch and then punching out the preliminary laminated body by advancing the punch. Also in this case, before the shearing by the punch and the die, it is possible to provide the notch by the protruding portion, and the shearing by the punch and the die can be smoothly performed. Therefore, deformation of the ceramic layer and the internal electrode layer due to shear stress can be further suppressed.
[0021]
Further, the punching hole of the die is provided with a cradle for receiving the punched unit body, and the unit bodies generated by the continuous punching process are sequentially stacked on the cradle. (Claim 9). In this case, a plurality of unit bodies stacked on the cradle can be handled integrally, and further rationalization at the time of manufacture can be achieved. Further, the unit body immediately after punching can be supported by the cradle, and the effect of reducing warpage or deformation can be enhanced.
[0022]
Furthermore, it is preferable that the unit bodies are sequentially stacked on the cradle and are sequentially crimped. In this case, a plurality of unit bodies can be handled in a pressure-bonded state, and rationalization at the time of manufacturing can be achieved.
[0023]
【Example】
Example 1
A method for manufacturing a ceramic laminate according to an embodiment of the present invention will be described with reference to FIGS.
In this example, as shown in FIG. 9, a method for manufacturing a ceramic laminate 1 in which ceramic layers 11 and internal electrode layers 2 are alternately laminated is manufactured.
In this manufacturing method, as shown in FIG. 1, at least the following primary pressure bonding step S4, unit cutting step S5, secondary pressure bonding step S6, degreasing step S7, and firing step S8 are performed.
[0024]
In the primary pressure-bonding step S4, as shown in FIGS. 2A to 2C, a wide ceramic sheet 110 including a plurality of ceramic layers 11 in the width direction is stacked and heated by a number smaller than the final number of layers. At the same time, the pre-laminated body 111 is formed by pressing in the laminating direction.
In the unit cutting step S5, as shown in FIG. 2 (d), a single ceramic layer is formed by punching the preliminary laminated body 111 so that the outer peripheral portion has a smooth curved surface (in this example, circular). This is a step of forming the unit body 115 having a width dimension included in the width direction and having a smaller number of layers than the final number of layers.
[0025]
In the secondary crimping step S6, as shown in FIGS. 2 (e), 4 and 5, a plurality of unit bodies 115 are laminated, heated and pressed in the laminating direction to form the ceramic laminate 1. It is a process.
The degreasing step S7 is a step of heating and removing the binder resin contained in the ceramic layer 11 of the ceramic laminate 1 by 90% or more.
The firing step S8 is a step of firing the ceramic laminate 1.
This will be described in detail below.
[0026]
In this example, in manufacturing the ceramic laminate 1, first, as shown in FIG. 1, a sheet forming step S 1 for forming a long ceramic sheet serving as a base of the ceramic layer 11, and a predetermined length from the long ceramic sheet. A sheet punching step S2 is performed to punch out a ceramic sheet 110 (FIG. 2) having a size of.
[0027]
The sheet forming step S1 may employ a doctor blade method, an extrusion method, or other various methods. In this example, a long ceramic sheet wound up in a roll shape by the doctor blade method is produced. As this raw material, one prepared so as to become a desired piezoelectric ceramic after firing is used. Specifically, various raw materials can be used. In this example, a raw material that becomes PZT (lead zirconate titanate) was used.
In the sheet punching step S2, a ceramic sheet 110 having a size capable of collecting 16 ceramic layers 11 is cut out from the long ceramic sheet.
[0028]
Next, as shown in FIGS. 1 and 2A, an internal electrode printing step S3 is performed. In this step, the internal electrode layer 2 is pattern printed on each ceramic sheet 110. At this time, the printing position of the internal electrode layer 2 is set so that the holding portion 15 (FIG. 6) is finally formed on the ceramic layer 11.
[0029]
In this example, the thickness of the ceramic sheet 110, that is, the ceramic layer 11, is set to 80 μm after firing, and the thickness of the internal electrode layer 2 is set to 2 μm after firing. That is, in this example, the final thickness of the internal electrode layer 2 is set to be 1/40 of the thickness of the ceramic layer 11.
[0030]
Next, as shown in FIGS. 1, 2B and 2C, a primary pressure bonding step S4 is performed. In this primary pressure bonding step S4, ten ceramic sheets 110 on which the internal electrode layer 2 has been printed are laminated and thermocompression bonded. In FIG. 2, the number and the like are simplified. The thermocompression bonding conditions at this time are performed under conditions of a lower temperature and a lower pressure than the secondary pressure bonding step S6 described later. Specific conditions were such that the heating temperature was 80 ° C., the applied pressure was 5 MPa, and pressing was performed for 3 minutes with a jig (not shown) only from above and below.
Further, the ceramic sheets 110 are stacked such that the positions of the holding portions 15 where the internal electrodes 2 do not exist are alternately shifted left and right in the stacked state. Thereby, the wide preliminary | backup laminated body 111 is obtained.
[0031]
Next, as shown in FIGS. 1, 2 (d), and 3, a unit cutting step S5 is performed. In this unit cutting step S5, the preliminary laminated body 111 formed by laminating 10 ceramic sheets 110 is cut into a plurality in the width direction. At this time, the preliminary laminated body 111 has a width dimension including the single ceramic layer 11 in the width direction by punching in a circular shape so that the outer peripheral portion has a smooth curved surface shape. A disk-shaped unit body 111 is obtained.
In this example, as shown in FIG. 3, in order to perform the punching, a die 61 having a punch 61 having a circular cross-sectional front end surface and a punching hole 620 that can be inserted into the punch 61 while maintaining a predetermined clearance. And performed. As the punch 61 and the die 62, ordinary ones were used without providing projections or the like.
[0032]
Further, in this example, the temperature at which this unit cutting step S5 is performed, that is, the temperature of the preliminary laminated body 111 at the time of cutting is 25 ° C. This is a temperature lower than the glass transition point 75 (° C.) of the resin binder included in the ceramic layer 11 and higher than −70 ° C. By performing punching at this temperature, punching with less deformation can be performed.
[0033]
Next, as shown in FIGS. 1, 2 (e), 2 (f), FIG. 4, and FIG. 5, 20 unit bodies 115 are stacked and the secondary crimping step S <b> 6 is performed.
Specifically, as shown in FIG. 4, as the side jig 71, a first side jig 711 having a semicircular cross section and a second side jig 712 having a semicircular cross section covering the first side jig 712 are used. Further, as the end surface jig 72, a pair of cylindrical members is used.
[0034]
Then, as shown in the figure, 20 unit bodies 115 are inserted into the recesses 713 of the first side surface jig 711 while being laminated. Next, the second side surface jig 712 is put on the first side surface jig 712. In this state, the end surface jig 72 is inserted into the concave portion 713 of the first side surface jig 711 from both ends of the side surface jig 71, and the thermocompression bonding process is performed.
[0035]
In this example, the laminate and the jig are heated to 120 ° C. for 30 minutes in a thermostatic bath. After that, it is moved to the press machine and crimped. Moreover, in this example, the applied pressure from the end surface jig 72 in the stacking direction was set to 34 MPa. In addition, heating temperature can be changed in 80-190 degreeC. Furthermore, the applied pressure can be changed in the range of 5 to 100 MPa. The pressurization and heating time can be changed depending on the size of the ceramic layer 11 and the number of laminated layers.
[0036]
Further, in this example, the heating and pressurization in the secondary pressure bonding step S6 was performed for a predetermined time, the applied pressure was removed, the end face jig 72 was removed, and the side face jig 71 was disassembled. Thereby, as shown in FIG.2 (f), the ceramic laminated body 1 which has a column shape was obtained.
[0037]
A development view of the ceramic laminate 1 is shown in FIG. As shown in the figure, each ceramic layer 11 and the internal electrode layer 2 constituting the ceramic laminate 1 have a circular shape. Moreover, the ceramic laminated body 1 has the holding | maintenance part 15 by which the internal electrode layer 2 does not exist between the adjacent ceramic layers 11 by turns.
[0038]
Next, as shown in FIG. 1, a degreasing step S7 is performed in which the binder resin contained in the ceramic layer 11 of the ceramic laminate 1 is removed by heating by 90% or more. Specifically, the ceramic laminate 1 is heated in an air atmosphere at a temperature of 350 ° C. and a holding time of 5 hours to remove the binder resin.
[0039]
Next, as shown in FIG. 1, a firing step S8 for firing the ceramic laminate 1 after degreasing is performed. In this example, the heating temperature was 1100 ° C. and the holding time was 2 hours.
[0040]
Next, in this example, as shown in FIGS. 1 and 7, a side grinding step S9 is performed.
As shown in FIG. 7, centerless grinding is performed using a pair of drum-shaped grindstones 5. Specifically, the cylindrical ceramic laminated body 1 is positioned between the grindstones 5 that rotate with each other, and this is gradually moved continuously in the axial direction without fixing its center. As a result, the side surfaces of the ceramic laminates 1 are uniformly polished.
[0041]
Next, as shown in FIG. 8, the two opposing surfaces having the holding portion 12 are ground flat to provide the side flat portions 101 and 102. The other side surfaces 103 and 104 remain arcuate. Thereby, as shown in FIG. 9, the ceramic laminated body 1 whose cross-sectional shape is a barrel shape is obtained.
[0042]
Next, the effect of this example will be described.
In this example, after producing the preliminary | backup laminated body 11 in the said primary crimping | compression-bonding process S4, this is cut | disconnected to the several unit body 115 in the said unit cutting process S5. At this time, the outer peripheral shape of the unit body is punched into a circular shape.
Therefore, there is almost no concentration of punching stress when punching in the unit cutting step S5. Therefore, in the cut unit body 115, the internal electrode layer 2 can be prevented from being greatly deformed. Therefore, even after the subsequent degreasing step S7 and firing step S8, the occurrence of delamination and cracks due to the deformation of the internal electrode layer 2 can be suppressed.
[0043]
Further, in the unit cutting step S5, the preliminary laminated body 11 formed by previously laminating a plurality of ceramic sheets 110 is cut. Therefore, the unit body 115 can be handled in the unit of the number of layers of the preliminary laminated body 11, and the production efficiency is not lowered as in the case of handling the ceramic layers 11 one by one.
[0044]
Furthermore, in this example, as described above, the cylindrical ceramic laminate 1 can be centerless ground at the beginning of the grinding step. Therefore, the plurality of ceramic laminates 1 can be continuously ground (polished). This process is not possible in the case of a quadrangular prism ceramic laminate. Therefore, also in this respect, the production efficiency can be improved as compared with the case of using a rectangular unit body.
[0045]
Further, in this example, as described above, in the unit cutting step S5, since it is punched into a circular shape, an excess portion is generated as waste. However, since this debris has not been subjected to a degreasing process, it can be reused as a raw material for the ceramic sheet, and the material yield can be improved.
[0046]
In this example, the thickness of the internal electrode layer 2 is set to 1/40 of the thickness of the ceramic layer 11 as described above. Thereby, the influence on the occurrence of delamination and cracks due to the presence of the internal electrode layer 2 can be reduced, and sufficient electrical characteristics can be maintained.
[0047]
In addition, the ceramic laminated body 1 of this example uses piezoelectric ceramics as the ceramic layer 11, and can be used as a piezoelectric actuator. In addition, as described above, generation of delamination and cracks is suppressed in the ceramic laminate 1. Therefore, excellent durability can be achieved even when it is built in an injector, which is used very severely.
[0048]
(Example 2)
In this example, another example of the punching method applicable to the unit cutting step S5 of Example 1 is shown.
As shown in FIG. 10, in this example, in addition to the punch 61 and the die 62, an apparatus having a stripper 63 disposed separately from the punch 61 so as to be able to advance and retract is used. The punch 61 has a circular tip surface. The die 62 has a punched hole 620 that can be inserted into the punch 61 with a predetermined clearance. The stripper 63 has a protrusion 631 at its tip.
[0049]
In this example, the punching hole 620 of the die 62 is provided with a receiving base 625 for receiving the punched unit body 115. The cradle 625 is provided with a suction port on the surface thereof, and is configured to adsorb the punched unit body 115 by applying a negative pressure thereto.
[0050]
When the unit cutting step S5 is performed using this apparatus, the stripper 63 is first moved forward with respect to the preliminary laminated body 111 placed on the die 62, and the protrusion 631 is formed in the thickness of the preliminary laminated body 111. Make a cut in the middle. Thereafter, the punch 61 is advanced to punch out the preliminary laminated body 111 to form a disk-shaped unit body 115.
[0051]
Thereby, before performing the shearing by the punch 61 and the die 62, it is possible to provide the notch by the protruding portion 631, and the shearing by the punch 61 and the die 62 can be smoothly performed. Therefore, deformation of the ceramic layer 11 and the internal electrode layer 2 due to shear stress can be further suppressed.
[0052]
In this example, since the cradle 625 is provided, the unit bodies 115 are sequentially stacked on the cradle 625 by moving the preliminary laminated body 111 and continuously cutting the next unit body 115. The Therefore, a plurality of obtained unit bodies 115 can be handled together in a stacked state, and the manufacturing efficiency can be improved.
In other respects, the same effects as those of the first embodiment can be obtained.
[0053]
(Example 3)
In this example, another example of the punching method applicable to the unit cutting step S5 of the first embodiment is further shown.
As shown in FIG. 11, the apparatus used in the present example is the one in which the vertical relationship is reversed from that in the second embodiment.
That is, in this example, the die 62 and the cradle 64 are disposed above, and the punch 61 and the stripper 63 are disposed below.
Further, the stripper 63 is provided with a protrusion 631 at the tip thereof.
[0054]
In this example, the punching hole 620 of the die 62 is provided with a receiving base 625 for receiving the punched unit body 115. The cradle 625 is provided with a suction port on the surface thereof, and is configured to adsorb the punched unit body 115 by applying a negative pressure thereto.
[0055]
When the unit cutting step S5 is performed using this apparatus, the preliminary laminated body 111 placed on the stripper 63 is raised along with the rising of the stripper 63 and brought into contact with the die 62, and the stripper 63 is further moved. The protrusion 631 is pierced to the middle of the thickness of the preliminary laminated body 111 by moving forward, and a cut is provided. Thereafter, the punch 61 is advanced (raised) to punch out the preliminary laminated body 111 to form a disk-shaped unit body 115.
[0056]
In this example, since the receiving table 625 is provided, the punched unit body 115 is sucked and held by the receiving table 625. Next, when the second and subsequent unit bodies 115 are punched out, the unit bodies 115 are preliminarily pressure-bonded sequentially to the previously punched unit bodies 115 by the press pressure at the time of punching. Therefore, all the punched unit bodies 115 are held by the suction force. Thereby, handling of the subsequent unit body 115 becomes still easier.
In other respects, the same effects as those of the first and second embodiments can be obtained.
[0057]
Example 4
In this example, in the unit cutting step S5 of Example 1, the effect of reducing warpage by punching so that the outer peripheral portion has a smooth curved surface shape was quantitatively determined. Specifically, an experiment was performed comparing the case of punching the unit body 115 into a circular shape as a representative shape having a smooth curved surface at the outer peripheral portion and the case of punching the unit body into a square shape.
[0058]
Four types of punching methods were performed.
The first method is a method using only the punch 61 and the die 62 as shown in FIG.
In the second method, as shown in FIG. 10, a stripper 63 is provided around the punch 61 as in the second embodiment, and the stripper 63 is provided with a projection 631 similar to the above. A device that was not used was used.
In the third method, an apparatus in which a protrusion (not shown) protruding toward the punch side is provided around the punching hole 620 of the die 62 in the first embodiment.
The fourth method is an example in which the cradle 64 is provided in the apparatus of the second method and is exactly the same as the second embodiment.
In either method, the shape of the punch and the punched hole was switched to a circle or a rectangle according to the desired shape.
[0059]
The result of the experiment is shown in FIG. In this figure, the horizontal axis represents the punching method, and the vertical axis represents the warpage (mm) measured after cutting. As shown in FIG. 13, the amount of warpage is obtained by ba (mm) where a is the height in the state (a) without warp and b is the maximum height in the state (b) with warp. It was.
[0060]
As can be seen from the figure, the round shape with a smooth curve without corners has less warpage than the square with corners, regardless of which punching method is used. In addition, it was found that the use of a stripper having protrusions, the arrangement of protrusions on the die, the arrangement of the cradle, etc. are more effective in improving warpage than the case of using only a combination of a normal punch and die.
[0061]
(Example 5)
In this example, the correlation between the temperature, warpage, and delamination failure of the preliminary laminated body 111 in the unit cutting step S5 of Example 1 was obtained.
Specifically, using the same cutting method as in Example 1, only the temperature of the preliminary laminated body 111 was changed, and unit bodies were respectively produced. The amount of warpage was measured. Moreover, the final-shaped ceramic laminate 1 was produced using each unit body in the same manner as in Example 1, and the occurrence rate of delamination defects was examined.
[0062]
The result is shown in FIG. In this figure, the horizontal axis represents the punching temperature (temperature of the preliminary laminate), the left vertical axis represents warpage (mm), and the right vertical axis represents the delamination defect rate (%).
As can be seen from the figure, the warp is better when the punching temperature is lower, but the delamination defect tends to increase when the temperature is too low or too high. From the result of this example, the delamination increases rapidly when the temperature is lower than -70 ° C, and the delamination gradually increases when the temperature is higher than the glass transition point G of the binder resin of the ceramic layer. It can be seen that the unit cutting step S5 is preferably punched at a temperature in the range of (° C.).
[0063]
In each of the above embodiments, the unit body is punched so as to be circular. However, the present invention is not limited to the circular shape, and the barrel-shaped unit body 115 as shown in FIG. 15 or as shown in FIG. However, the other portion may have a substantially circular shape having a substantially circular shape. Moreover, an octagon shape may be sufficient as it mentions later. In particular, by providing the above-described potch portion 118, rotation around the axis of the laminated body during crimping can be suppressed, and a uniform product can be obtained.
[0064]
(Example 6)
In this example, as shown in FIGS. 17 and 18, the ceramic laminated body 1 is manufactured with one unit body 115.
In this manufacturing method, as shown in FIG. 17, a sheet forming step S201, a sheet punching step S202, and an internal electrode printing step S203 are performed as in the first embodiment. Thereafter, as shown in FIGS. 17 and 18A to 18C, the crimping step S204 is performed.
[0065]
The conditions of this crimping step S204 were a heating temperature of 120 ° C., a pressure of 15 MPa, and a holding time of 3 minutes. Next, a unit cutting step S205 for cutting the unit body 115 from the obtained preliminary laminated body 111 is performed.
In this example, as shown in FIG. 18D, an octagonal unit body 115 in which four corners of a square are dropped is obtained. That is, in this example, as the cut shape of the unit body, a polygonal shape in which the inner angles of all the corners exceed 90 ° is adopted.
[0066]
Next, in this example, degreasing process S206 and baking process S207 were performed on the same conditions as Example 1. FIG.
Thereafter, a side grinding step S208 is performed. In the side grinding step S208 of this example, the entire shape was maintained to be an octagonal column.
[0067]
As described above, in this example, the ceramic laminate 1 is manufactured by using one unit body 115. In this case, the same effects as those of the first embodiment can be obtained.
That is, in this example, in the unit cutting step S205, all corners are punched into octagons having a polygonal shape exceeding 90 °. Thereby, there is almost no concentration of punching stress at the time of punching in the unit cutting step S205. Therefore, in the cut unit body 115, the internal electrode layer 2 can be prevented from being greatly deformed. Therefore, even after the subsequent degreasing step S207 and firing step S208, the occurrence of delamination and cracks due to the deformation of the internal electrode layer 2 can be suppressed.
Other effects similar to those of the first embodiment can be obtained.
[0068]
(Example 7)
As shown in FIGS. 20 and 21, this example is an example in which a ceramic laminate 1 having the same shape as that of Example 6 and having a large dimension in the lamination direction is produced.
In this example, as shown in FIG. 20, the same sheet forming step S401, sheet punching step S402, internal electrode printing step S403, pressure bonding step S404, unit cutting step S405, degreasing step S406, and firing step S407 as in Example 6 are performed. Thus, a plurality of fired unit bodies 115 are obtained.
[0069]
Next, as shown in FIG. 20 and FIG. 21, the unit bodies 115 were stacked via the adhesive layer 4 (adhesion step S408). Thereby, a ceramic laminate having a large dimension in the lamination direction can be obtained.
In this example as well, the side grinding step S409 was performed last.
Further, the side grinding step S409 can be performed before the bonding step S408.
In the case of this example, the same effect as that of the sixth embodiment can be obtained.
[0070]
(Example 8)
In this example, as shown in FIGS. 22 and 23, in order to increase the dimension in the stacking direction of the ceramic laminated body having the same shape as that of the sixth embodiment, the second press bonding similar to that of the first embodiment is performed in the manufacturing process of the sixth embodiment. In this example, step S306 is added.
That is, in this example, as shown in FIG. 22, the sheet forming step S301, the sheet punching step S302, the internal electrode printing step S303, the primary pressure bonding step S304, and the unit cutting step S305 are performed as in the first embodiment. This unit cutting step S305 has an octagonal shape as in Example 6.
[0071]
Next, as shown in FIGS. 23D to 23F, the secondary pressure bonding step S306 is performed. This condition was the same as in Example 1.
Thereafter, a degreasing step S307, a firing step S308, and a side grinding step S309 are performed to obtain a ceramic laminate 1 having a high lamination height as shown in FIG.
In this case, the same effects as those of the first and sixth embodiments can be obtained.
In addition, in this example, the ceramic laminated body of the lamination | stacking height at the time of secondary pressure bonding was obtained, but this was laminated | stacked through the contact bonding layer similarly to Example 7, and the ceramic laminated body with a higher lamination | stacking height was further obtained. Of course it is also possible to obtain.
[0072]
Example 9
Next, in this example, as shown in FIG. 25, an example of the shape of the internal electrode layer 2 that can be employed in the ceramic laminates in Examples 6 to 9 is shown.
As the internal electrode layer 2 in this example, two types of shapes were alternately arranged as shown in FIGS.
[0073]
Each internal electrode layer 2 has holding portions 151 and 152, respectively. As shown in FIG. 25 (a), the shape of one holding portion 151 is one long side and two short sides surrounding it, out of a substantially octagon in which four long sides and four short sides are alternately connected. Is provided only on the outer peripheral side. As shown in FIG. 5B, the other holding portion 152 is provided on the outer peripheral side of seven sides excluding one long side.
[0074]
In the stacked state, the internal electrode layer regions 251 in contact with the sides H1 to H5 and the internal electrode layer regions 252 in contact with the side H7 in FIG. The internal electrode layer 2 always exists in the octagonal region 250. Thereby, when arranging the pair of side electrodes, one side electrode can be arranged at a position in contact with any one of the regions 251 and the other side electrode can be arranged at a position in contact with the region 252. .
In addition, the shape of the internal electrode layer 2 of this example is an example, and can be changed to other shapes.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a manufacturing process in Example 1. FIG.
2 is an explanatory view showing a manufacturing process in Example 1. FIG.
FIG. 3 is an explanatory view showing an apparatus used for a unit cutting step in the first embodiment.
4 is an explanatory view showing a jig used in a thermocompression bonding process in Example 1. FIG.
5 is an explanatory view showing a state in which a thermocompression bonding process is performed in Example 1. FIG.
6 is a development explanatory view showing a laminated state of ceramic layers in Example 1. FIG.
7 is an explanatory view showing a state in which centerless grinding is performed in the side grinding process in Embodiment 1. FIG.
FIG. 8 is an explanatory view showing a state in which a side flat portion is formed in the side grinding step in the first embodiment.
9 is a perspective view showing a ceramic laminated body having a barrel shape in cross section in Example 1. FIG.
10 is an explanatory view showing an apparatus used for a unit cutting step in Embodiment 2. FIG.
FIG. 11 is an explanatory view showing an apparatus used for a unit cutting step in Example 3.
12 is an explanatory diagram showing a relationship between a punching method and a warpage amount in Embodiment 4. FIG.
13 is an explanatory diagram showing the definition of the amount of warpage in Embodiment 4. FIG.
14 is an explanatory diagram showing the relationship between the punching temperature, the delamination defect, and the amount of warpage in Example 5. FIG.
FIG. 15 is an explanatory diagram showing an example in which the punching shape of the unit body is a barrel shape.
FIG. 16 is an explanatory diagram showing an example in which the punching shape of the unit body is a substantially circular shape.
17 is a process chart showing a manufacturing process in Example 6. FIG.
18 is an explanatory diagram showing a manufacturing process in Example 6. FIG.
19 is a perspective view of a ceramic laminate in Example 6. FIG.
20 is a process diagram showing a manufacturing process in Example 7. FIG.
21 is a perspective view of a ceramic laminate in Example 7. FIG.
22 is a process chart showing a production process in Example 8. FIG.
23 is an explanatory diagram showing a manufacturing process in Example 8. FIG.
24 is a perspective view of a ceramic laminate in Example 8. FIG.
25 is an explanatory diagram showing the shape of the internal electrode layer in Example 9. FIG.
[Explanation of symbols]
1. . . Ceramic laminate,
11. . . Ceramic layer,
110. . . Ceramic sheet,
111. . . Preliminary laminate,
115. . . Unit body,
15. . . Memorandum,
2. . . Internal electrode layer,
71. . . Side jig,
711. . . First side jig,
712. . . Second side jig,
72. . . End face jig,

Claims (21)

In a method of manufacturing a ceramic laminate in which ceramic layers and internal electrode layers are alternately laminated,
A crimping step of laminating a wide ceramic sheet including a plurality of ceramic layers in the width direction, heating and pressing in the laminating direction to form a pre-laminated body;
A unit body having a width dimension including one ceramic layer in the width direction is punched out from the pre-laminated body so as to have a polygonal shape or a barrel shape in which the inner angles of all corners exceed 90 °. A unit cutting process to be formed;
A degreasing step of removing by heating 90% or more of the binder resin contained in the ceramic layer of the unit body;
And a firing process for firing the unit body.   2. The ceramic laminate according to claim 1, wherein a secondary press-bonding step is performed between the unit cutting step and the degreasing step by laminating a plurality of the unit bodies and heating and pressing in the laminating direction. Body manufacturing method.   3. The method of manufacturing a ceramic laminate according to claim 1, wherein the punching shape in the unit cutting step is an octagonal shape.   4. The method for manufacturing a ceramic laminate according to claim 1, wherein the thickness of the internal electrode layer is in a range of 1/100 to 1/10 of the thickness of the ceramic layer.   5. The cutting in the unit cutting step according to claim 1, wherein the cutting in the unit cutting step is −70 (° C.) to G when the glass transition point of the resin component contained in the ceramic layer is G (° C.). A method for producing a ceramic laminate, which is performed within a range of (° C.).   6. The method of manufacturing a ceramic laminate according to claim 1, wherein the ceramic laminate is a ceramic laminate for a piezoelectric actuator.   The unit cutting step according to any one of claims 1 to 6, wherein the unit cutting step includes a punch having a tip surface having a desired shape, and a die having a punched hole that can be inserted into the punch while maintaining a predetermined clearance. The at least one of the punch and the die is formed using a protrusion having a cut shape along the cutting shape, and the cut by the protrusion is provided before shearing by the punch and the die. A method for producing a ceramic laminate. The unit cutting step according to any one of claims 1 to 6 , wherein the unit cutting step includes a punch having a tip surface having a desired shape, a die having a punched hole that can be inserted into the punch while maintaining a predetermined clearance, and the punch. The outer periphery of the punch is disposed separately from the punch so as to be able to advance and retreat, and a tip having a protrusion at the tip thereof is used.
The stripper is advanced with respect to the preliminary laminated body placed on the die, and the protrusion is pierced to the middle of the thickness of the preliminary laminated body to provide a cut, and then the punch is advanced to advance the preliminary laminated body. A method for producing a ceramic laminate, comprising punching out the laminate to form the unit body.   9. The punching hole of the die according to claim 7, wherein a receiving base for receiving the punched unit body is provided in the punching hole, and the unit body generated by a continuous punching process is received by the receiving body. A method for producing a ceramic laminate, comprising sequentially laminating on a table.   10. The method for manufacturing a ceramic laminate according to claim 9, wherein the unit bodies are sequentially laminated on the cradle and sequentially pressed.   3. The method for manufacturing a ceramic laminate according to claim 2, wherein the crimping step is performed under conditions of lower temperature and lower pressure than the secondary crimping step.   12. The secondary press-bonding step according to claim 2, wherein the secondary press-bonding step is inserted in a concave portion of a side jig covering the side surface of the unit body, and heated in the stacking direction by inserting end face jigs from both ends of the side jig. A method for producing a ceramic laminate, comprising: In a method of manufacturing a ceramic laminate in which ceramic layers and internal electrode layers are alternately laminated,
A crimping step of laminating a wide ceramic sheet including a plurality of ceramic layers in the width direction, heating and pressing in the laminating direction to form a pre-laminated body;
By punching out the pre-laminated body so that all corners have a polygonal shape in which the inner angle exceeds 90 ° or the outer peripheral portion has a smooth curved surface shape, the preliminary laminated body has a width dimension including one ceramic layer in the width direction. A unit cutting step for forming a unit body,
A degreasing step of removing by heating 90% or more of the binder resin contained in the ceramic layer of the unit body;
A firing step of firing the unit body,
The unit cutting step includes a punch having a tip surface having a desired shape, and a die having a punched hole that can be inserted into the punch while maintaining a predetermined clearance, and at least one of the punch and the die includes: A method for producing a ceramic laminate, wherein the method comprises using a projection having a protruding portion along the cut shape, and providing a cut by the protruding portion before shearing by the punch and the die. In a method of manufacturing a ceramic laminate in which ceramic layers and internal electrode layers are alternately laminated,
A crimping step of laminating a wide ceramic sheet including a plurality of ceramic layers in the width direction, heating and pressing in the laminating direction to form a pre-laminated body;
By punching out the pre-laminated body so that all corners have a polygonal shape in which the inner angle exceeds 90 ° or the outer peripheral portion has a smooth curved surface shape, the preliminary laminated body has a width dimension including one ceramic layer in the width direction. A unit cutting step for forming a unit body,
A degreasing step of removing by heating 90% or more of the binder resin contained in the ceramic layer of the unit body;
A firing step of firing the unit body,
The unit cutting step includes a punch having a tip surface having a desired shape, a die having a punching hole that can be inserted into the punch while maintaining a predetermined clearance, and an outer periphery of the punch that can be moved forward and backward. And using a stripper with a protrusion at the tip,
The stripper is advanced with respect to the preliminary laminated body placed on the die, and the protrusion is pierced to the middle of the thickness of the preliminary laminated body to provide a cut, and then the punch is advanced to advance the preliminary laminated body. A method for producing a ceramic laminate, comprising punching out the laminate to form the unit body.   15. The punching hole of the die according to claim 13, wherein a receiving base for receiving the punched unit body is provided in the punching hole, and the unit body generated by a continuous punching process is received by the receiving body. A method for producing a ceramic laminate, comprising sequentially laminating on a table.   16. The method of manufacturing a ceramic laminate according to claim 15, wherein the unit bodies are sequentially laminated on the cradle and sequentially pressed.   17. The secondary pressure bonding step of stacking a plurality of the unit bodies and heating and pressurizing in the stacking direction is performed between the unit cutting step and the degreasing step. A method for producing a ceramic laminate, comprising:   The method for manufacturing a ceramic laminate according to any one of claims 13 to 17, wherein the punching shape in the unit cutting step is a circular shape, a barrel shape, or an octagonal shape.   19. The method for manufacturing a ceramic laminate according to claim 13, wherein the thickness of the internal electrode layer is in a range of 1/100 to 1/10 of the thickness of the ceramic layer.   20. The cutting in the unit cutting step according to claim 13, wherein the cutting in the unit cutting step is −70 (° C.) to G when the glass transition point of the resin component contained in the ceramic layer is G (° C.). A method for producing a ceramic laminate, which is performed within a range of (° C.).   21. The method for manufacturing a ceramic laminate according to claim 13, wherein the ceramic laminate is a ceramic laminate for a piezoelectric actuator.

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