KR19980070179A - Large flat sintered body having needle-aligned structure aligned in the same direction, manufacturing method and apparatus therefor - Google Patents

Abstract

As the sintered body having the structure in which the acicular crystal minerals are uniformly oriented in the same direction is proved that orientation is an important factor such as strength in the theory of polymers or metal materials, the problem of the present invention is that the acicular crystal minerals are formed by acicular crystal minerals. The task is to establish conditions for producing a large flat plate-shaped sintered body having a reinforced and uniform compounding structure.

In order to solve this problem, in the present invention, a wollastonite containing β-CaO.SiO ₂ , which is acicular crystal mineral, is used as a raw material to enhance the orientation of the acicular crystal mineral in the clay. As a manufacturing method, a method in which rigid force is not applied from the side when extruding the clay by a rolling mill is used. In addition, as an apparatus, the magnetic bearing of the extruder of the rolling mill was developed and used freely, and the orientation of the needle crystal was strengthened, and the torsional return roller was used as the best orientation. As a result, the bending strength has more than doubled the conventional one.

Description

Large flat sintered body having needle-aligned structure aligned in the same direction, manufacturing method and apparatus

TECHNICAL FIELD This invention improves the "soft property" which is the largest drawback of ceramic sintered compacts, and relates to the technique of manufacturing the large size building ceramic tile with elasticity. In addition, the present invention relates to an elastic ceramic tile which is a significant advance in the prior art in these technical fields.

The prior art related to the present invention is Japanese Patent No. 1366443, Japanese Patent No. 1576834, Japanese Patent No. 1584970, and US Patent No. 4,495,118, West Germany Patent No. 3,313,596, which were obtained by filing a domestic application abroad. , British Patent 2,317,552, Australian Patent 541,735 and are already widely industrially produced by their technology. An important point of the prior art is briefly described as follows.

1) First Prior Art

The contents of Japanese Patent No. 1326443 (Japanese Patent Application No. 54-129476, Japanese Special Application No. 61-30887) refer to a roller in which a soft clay-like plastic pottery raw material composition is removed from a clasp by a plate and molded. It is a shaping | molding method of the plate-shaped porcelain molded object which has the process of rolling a composition in between a pair or several pair of rollers which have a helical surface groove sent to mutually opposite directions toward a center part. In other words, when molding plate-shaped porcelain molded body from the raw material composition of soft earth-like plastic porcelain, the constant directionality due to the distribution of the internal density difference or the orientation of particles due to the ejection flow resistance from the clasp which becomes a big defect and obstacle It is a technique of forming a molded article having a homogeneous internal structure as a whole.

2) Second prior art

The contents of Japanese Patent No. 1576834 (Japanese Patent Application No. 56-174528, Japanese Patent Application Publication No. 1-60403) open the tubular dough where the cross section taken out from the molding machine is curved to make a plate-like dough. It is a manufacturing method of the ceramic plate characterized by rolling a dough in the same direction as the direction with which it removes from a said molding machine, and drying it, and baking it by a roller hasklen so that the said direction may be a conveyance direction. In other words, the manufacturing method of the porcelain plate is a technique of a method of efficiently producing a thin and thin porcelain plate in particular.

3) Third Prior Art

The content of Japanese Patent No. 1584970 (Japanese Special Application 59-39374, Japanese Special Publication 1-59231)

(1) At least 30 [% by weight] containing at least 30 [% by weight] of all the plate-shaped or lobe-shaped small pieces or crystals containing βCaO · SiO ₂ and natural mica-based minerals; the βCaO · SiO ₂ is also superior ceramic sintered body (the following βCaO · SiO ₂ a refers to the element 1, and a mica group mineral plate-like or yeoppyeon shape of small pieces, including the cutting workability, characterized in that the sintering below the Mohs hardness of 5 Or the decision is called factor 2). Also

(2) At least one of the raw materials containing urea 1 and having a Mohs hardness of 5 or less and the raw materials having MOS hardness of 5 or less, and the total of the elements 1 and 2 in the sintered body base is 60 [weight% Above, and at least 30% by weight of β-CaOSiO ₂ is mixed to adjust the crushing and mixing to the extent that the plate-shaped or leaf-shaped small pieces or crystals are roughly left. It is a method for producing a ceramic sintered body excellent in machinability, characterized by sintering at a Mohs hardness of 5 or less at 1200 [deg.] C. or less to an extent that substantially retains. That is, it is the technique of the ceramic sintered compact which is excellent in the workability which is completely different from the conventional ceramic sintered compact, and its manufacturing method.

These various prior arts are still insufficient to make the softness of the large-scale building ceramic tile, which is the object of the present invention, to be smaller and more elastic. Pointing them out for each prior art is as follows.

1) In the first conventional technology, a plastic ceramic raw material is taken out of a rolling mill and formed into a cylindrical shape, in which a core in the center of the clasp is rigidly supported by an inner bead support shaft fixed to the main screw shaft. Since it is supported, there is a problem that the orientation of the thin elongated pieces existing inside the raw material in the shape of a lead is rather disturbed. In addition, since the prior art targets only flat crystal grains generally present in the ceramic raw material composition, selection of the raw material itself is insufficient.

2) The second conventional technique is to spread the cylindrical dough removed from the rolling mill to form a plate-like dough, and to roll it in the same direction so that the ejected direction becomes the conveying direction, but the orientation is disturbed by the rigid middle axis. It is not enough because it tends to cause it. Moreover, since the raw material itself is not specifically selected, there exists a problem that it is still inadequate as a manufacturing method of a ceramic sinter of a large thickness.

3) The third conventional technique is a ceramic sintered body excellent in workability and a manufacturing method thereof for the purpose. In this method, a large flat ceramic sintered body which is extremely small in dimensional deformation is not necessarily manufactured. In addition, this conventional technique has a problem in that it is not sufficient for the production of the large plate-like sintered compact because no special measures are taken for the orientation of the elongated material in the soft soil raw material in the soft soil process.

The following will be described in detail. In Japanese Patent No. 1584970, the main element of the present invention, β-CaO · SiO _2, that is, wollastonite, which is a needle crystal mineral, is almost identical. In addition, it is used as a feature of hardness and also has the characteristic that a high enough strength can be obtained even if a glass phase is not generated like general ceramics, and the invention is not considered especially in the alignment orientation of wollastonite. In addition, Japanese Patent No. 1576834 is currently employed in industrial production, and is employed in the technology of manufacturing thin and large-sized ceramic tiles. Although foreign patents also form the basis of these manufacturing methods, the purpose of this invention is to characterize the orientation of kaolinite, which is a ribbon-like crystal mineral, which is a general ceramic material, and has a small effect of improving the strength as a sintered body, and reducing the defect rate. The purpose is to. As described above, an object of the present invention is to produce a product having a strength and elasticity as a sintered body having a structure in which crystals of wollastonite, which are acicular crystal minerals, are uniformly aligned in the same direction. As described in Japanese Patent No. 1576834, the crystal orientation of kaolinite is dried in the dough and the first roasting step up to about 700 [deg.] C. shows the effect of the orientation as a ribbon-shaped crystal, but when it exceeds 800 [deg.] C., it is dehydrated and amorphous. The form of needle-like βCaO · SiO ₂ in wollastonite is useful as a reinforcing structure of the sintered body maintained up to around 1200 [deg.] C. In addition, many experiments differed from soft ribbon-like crystals such as kaolinite, and wollastonite, which is a strong needle-like raw material, was easily oriented when pressed and flowed as a plastic clay composition. It was easy to deform. Here, the points of the conventional apparatus will be described. 3 is an explanatory view of the discharge half of the conventional vacuum mill. The clay 7 is extruded to the left by the screw 6 of the main screw shaft 5 provided in the outer body 1. Periphery of the inner bead 2 rigidly fixed to the inner bead shaft 3 rigidly fixed to the inner bead support frame 8 through between the inner bead support frames 8 rigidly fixed to the outer body 1. Passing between and the outer body 1, the clay (7) is extruded from the clasp (14). Since the inner bead shaft 3 and the inner bead 2 are rigidly fixed, the needle crystal 9 in the clay 7 causes the orientation to be disturbed in these.

Therefore, the present invention eliminates the problems and all the shortcomings of the prior arts, and develops new means to advance the technology. The present invention also expects a performance improvement effect such as strong strength and orients the wollastonite which is acicular crystal mineral. It is aimed at the large clasp sintered compact which has a structure made. Therefore, a key point for achieving the object of the present invention should be to solve how to achieve uniform alignment with low potential distortion under each condition of the manufacturing plant.

In other words, an object of the present invention is to make a super-thick plate-shaped ceramic sintered body which could not be manufactured in the first place and to provide the production method and the apparatus together.

The present invention has developed the following means to solve the above problems.

First, the characteristics of the large flat plate-like sintered body in which the acicular crystal mineral of the present invention has a structure aligned in the same direction are characterized by 30 to 70 [% by weight] of β-CaO · SiO ₂ , which is acicular crystal mineral, And 70-30 [% by weight] of the common porcelain containing talc in anhydrous terms in a homogeneous manner, and the acicular crystal minerals are uniformly aligned in the same direction to be molded into the required shape. It is sintered in the temperature range.

Secondly, the characteristic of the method for producing a large plate-shaped sintered compact in which the needle crystal mineral of the present invention has a structure aligned in the same direction is a raw material containing β-CaO.SiO ₂ needle crystal mineral. 30 to 70 [% by weight] of wollastonite having an aspect ratio of 20 or more in anhydrous ratio of 1 [mm] or more, 60 to 30 [% by weight] of plastic clay raw material in anhydrous conversion and hydrophobicity of the orientation improving material Talc as a lubricant is adjusted to 10 [20% by weight] and, if necessary, at least one of the raw materials for general ceramics selected from feldspar, pottery and chamotte to 0 [30% by weight]. Pour water into a cylindrical shape by vacuum-equipment apparatus by homogenizing and adjusting the content rate to 14-20 [weight%], and then cutting it out and developing it into a plate shape. To the desired thickness and the size of the plate-like dough by rolling the roller in the same direction as the direction, and then is baked at a temperature range of 1000-1250 [℃] After drying the plate-like dough.

Thirdly, the following features of the method for producing a large flat plate-shaped sintered compact in which the needle crystal minerals of the present invention have a structure aligned in the same direction are as follows. / Cm2], and the shaft and bearing supporting the inner bead of the clasp composed of the outer body and the inner bead in the vacuum mill are insulated from the rotation of the main screw shaft of the vacuum mill. By rotating and displacing freely, the orientation of the acicular crystal in the soil is improved, and the thickness of the cylindrical molded body is automatically adjusted, and then the cylindrical dough is cut out and developed into a flat plate, and the same direction as the extrusion direction. It is to roll the dough molded by using a rolling roller.

Fourth, another feature of the manufacturing method of the large flat plate-shaped sintered compact in which the acicular crystal mineral of the present invention has a structure aligned in the same direction is a method of rolling the molded dough as described above using a rolling roller. This first rolling roller was rolled by a pair of rollers having a spiral groove rolling while giving reverse twist to restore the curved alignment structure caused by the turning of the main screw of the vacuum mill, Rolling process is to roll the plate-shaped dough of the desired thickness and size.

Fifthly, the manufacturing method of the large plate-shaped sintered compact in which the acicular crystal mineral of the present invention has a structure aligned in the same direction is characterized in that the main screw is housed in a similar cylindrical outer body and conveys the clay; An electric motor rotating a shaft, a hopper provided at an upper end of the similar cylindrical outer body for feeding the clay into the main screw, a vacuum chamber provided in the similar cylindrical outer body, an inner bead supporting shaft and an inner bead And a vacuum mill having a clasp for extruding the clay which excludes air from the vacuum chamber, wherein an inner bead bearing case is provided at a junction between the main screw shaft and the inner bead supporting shaft to prevent the penetration of the clay. The inner bead bearing is provided with a thrust bearing insulated rigidly inside the inner bead bearing case, The inner bead shaft and the inner bead are flexibly operated in accordance with the flow of the clay, so that the needle crystals contained in the clay are oriented without resistance in the same direction.

The following describes in detail with respect to each feature of the present invention described above. Conventionally, when wet extrusion molding a general ceramic tile or vortex using a vacuum mill, the basic problem has been scientifically interpreted by the literature since ancient times. There are also numerous patents for these countermeasures, but in the process of the clay being pushed by the screw being pivoted and shaped through certain clasps, the potential by the pressing force when even crystals such as flexible kaolinite, such as clay, are oriented Distortion remains as shape memory and is restored during drying or firing to increase the defective rate. In addition, when the shape of the forming clasp is rectangular, a difference occurs in the extruding speed due to the difference in frictional resistance between the inner wall portion of the clasp and the center portion, and in particular, the overflow occurs in the mold inner wall portion, resulting in a remarkably disturbed alignment structure. Common sense is known by. Japanese Patent No. 1576834 mentioned above improves this point and improves it by using a cylindrical clasp, but after several years of manufacturing experience, if a difference in thickness occurs in cylindrical dough, it remains as a potential distortion and the defect rate increases. In the present invention, the invention has been invented by improving the molding clasp and peripheral equipment as shown in (Claim 3). However, since these are only the improvement of the clasp, the spiral orientation caused by the turning screw becomes a latent distortion and is restored after drying and firing, as shown in (claim 4). The invention invented the method of obtaining the dough which has uniformly correct orientation which provides and restores the groove | channel which twists and returns the "spiral orientation" which arose in rotation. The limit of the content rate of the raw material of the composition shown in claim 1 is limited as described above when the wollastonite is 30 [%] or less, sufficient orientation and reinforcing effect cannot be obtained. It is because it was difficult to satisfy the physical property of the plastic clay which becomes a condition.

In addition, the content of clay raw material is at least good in the case of high quality and high plasticity clay in the range of the condition of plastic clay, but raw materials satisfying the conditions can not be obtained below 30 [%]. It is because it requires a long time and lowers productivity. It is because talc needs the range of 10 [%]-20 [%]. In order for plastic clay to be pressurized by a rolling mill and easy to align needles, raw materials having a role of a lubricant are needed. Although hydrophobic materials such as graphite and mica have been studied, they have about 30 volume ratios for needle crystals. It is because sufficient effect cannot be acquired if it does not occupy [%]. In addition, feldspars, pottery stones, and chamottes added as needed are selected or substituted to meet the productive requirements of the product to adjust the composition. In addition, under all conditions for achieving these objects, the extrusion pressure of the vacuum mill was set to 15 to 30 [kg / cm 2] because the restoration of potential distortion was not sufficient when the pressure exceeded 30 [kg / cm 2]. In addition, it is because it cannot endure the shear stress which arises at the time of rolling of a molded object below 15 [kg / cm <2>].

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional explanatory view of a needle crystal orientation function increasing device in the clay of the present invention.

Fig. 2 is an explanatory view of the needle crystal alignment action in the clay of the present invention, where (a) is a plan view and (b) is a side view.

3 is an explanatory cross-sectional view of the excavation apparatus of the clay rolling machine in the prior art.

※ Explanation of symbols about main part of drawing ※

1: Outer Body of Vacuum Torch 2: Inner Bead

3: inner bead shaft 4: inner bead bearing case

4a: ball bearing 4b: thrust bearing

4c: seal cover 5: screw shaft

6: screw 7: topsoil

8: inner bead support frame 9: couch determination

10: dough before rolling 11: groove

12: rolling roller pair 13: rolling dough

14: clasp

Next, embodiments of the present invention will be described in detail with reference to the drawings. First, in FIG. 1, the outer body 1 is disposed at the tip of a vacuum machine (not shown), and the inner bead 2 is disposed at the site of the clasp 14. In addition, a gap is set between the outer circumference of the inner bead 2 and the inner circumference of the clasp 14 of the outer body 1. The inner bead 2 is made of a plastic material in order to reduce the slip resistance and is formed in a cone shape as shown. The inner bead shaft 3 supporting the inner bead 2 is held by the thrust bearing 4b at the same time as its proximal end is held by the ball bearing 4a provided in the inner bead bearing case 4. Is supported. In addition, the seal cover 4c of the inner bead bearing case 4 is attached to protect the ball bearing 4a and the thrust bearing 4b by preventing the soil from invading. In addition, the inner bead shaft 3 is made of spring steel having a diameter of 8 to 15 [mm] to enable elastic deformation easily. Meanwhile, the screw shaft 5 having the screw 6 is connected to the inner bead bearing case 4.

With the above structure, the plastic clay which is extruded by the screw 6 by the rotation of the screw shaft 5 is sent while turning in the outer body 1, and in the part of the inner bead bearing case 4, part of the overflow state is And the orientation is scattered and then oriented again in the portion of the clasp 14 but is essentially extruded from the portion of the clasp 14 in a spirally oriented orientation as a whole. In addition, when a difference occurs in the thickness of the dough in the part of the clasp 14, the narrow part becomes faster, the wide part becomes slower, and the flow is automatically adjusted between several seconds. This adjustment is performed by the elastic deformation of the inner bead shaft 3.

In Fig. 2, the dough 10 before rolling is a clasp which is extruded by the vacuum mill shown in Fig. 1 and is cut and developed by cutting the clay. 9) is formed. The dough 10 before rolling is rolled by the rolling roller pair 12 which has the groove | channel in a direction opposite to the said spiral. The groove 11 of the rolling roller 12 has a depth of about 2 [mm], and arrange | positions the thing of the width of 4-5 [mm] by the pitch of 20-30 [mm]. The flat plate 10 rolled by the rolling roller pair 12 is twisted and returned to the needle crystal 9 by the groove 11 of the rolling roller pair 12, and the rolling dough which forms an almost serially aligned orientation. (13). In addition, although the rolling roller pair 12 was made into one end in FIG. 2, you may roll with the grooved roller which has the 2nd and 3rd stage torsion return groove | channels.

(Example)

The following describes an embodiment in which the ultra-thick ceramic sintered plate of the present invention is manufactured and manufactured under the following conditions.

1) Raw material

Wollastonite: USA NYCO company G grade 60-40 (mesh)

Chinese wollastonite 60-40 (mesh)

Clay: Motoyama Wood Express Limited

Talc: Less than 250 talc made in China

Feldspar: Soda Feldspar 250 (mesh) or less

2) adjustment of clay

The dry powder improved at a predetermined compounding ratio was added to the mix mara, mixed for 10 minutes, and then 20 [%] was added at an extra-moisture ratio and kneaded again for 10 minutes to obtain plastic clay.

3) Cylindrical Production

Diameter 250 [mm] (outside) The thing of thickness 25 [mm] is cut out and developed, and it is set as the production board before rolling of width 720-730 [mm], thickness 25 [mm], length 300 [mm], and said rolling roller. Primary rolling was carried out with the pair 12, and also three-stage rolling with the flat roller was made into the flat plate of thickness 5 [mm], width 700 [mm], and length about 1500 [mm].

4) Drying and Roasting

After drying for 5 minutes by far-infrared irradiation, it dried for 50 minutes to 350 degreeC with the mesh belt dryer, and then baked by the roller house kiln to the temperature of 1150 degreeC. Table 1 shows characteristics such as the blending ratio, water absorption rate and strength of the green flat plate as described above.

Properties such as compounding rate, water absorption rate and strength sample Silica (stone)% talc% clay% feldspar% Absorption rate% Bend Rigidity ㎏ / ㎠ Modulus of elasticity kgf / ㎠ Invention No1 50 10 40 - 12.5 565 35 x 10 ⁴ Conventional No2 - 10 40 50 6.3 310 80 x 10 ⁴

As can be seen from the above results, the effect given to the strength and elastic properties of wollastonite, which is acicular crystal mineral, is extremely large, and the conventional general ceramic composition shown in No2 has a very sinterability of about 1/2 of the present invention. Even when compared with the product, the bending strength of the present invention No1 is 1.7 to 1.8 times larger than that of the conventional product No2, and in particular, it can be seen that the elastic modulus of the present invention is particularly small and has two times or more of conventional brecchibility. Moreover, the invention of No1 had no deformation | transformation by the nonuniformity of an orientation, etc., and was able to obtain the thin and large ceramic tile which is not existed conventionally. In addition, following these examples, super-large plates having a maximum width of 1200 [mm], a length of 3000 [mm], and a thickness of 4 [mm] are produced.

As described above, the effects of the present invention are remarkably remarkable and enormous as follows.

(1) In the field of ceramic tiles widely used throughout the world as building materials, problems such as modernization of construction methods, rationalization by large-scale panels such as curtain walls, pollution of complexes and molds, etc. As a countermeasure is demanded by each manufacturer, research for the purpose of increasing the size and weight of each manufacturer is being conducted in full swing. However, in order to reduce the weight and make the size thinner and larger, "softness", the biggest drawback of the "pottery", occurs. In view of these problems, the present invention has a high elasticity (equivalent to asbestos plates) far beyond the common sense of the conventional "pottery", and shows breakthrough physical properties. This is the width 1.2 [mm] and the length 3 [mm] which the tile makers of the world have not yet reached, and it is inertia of the practical use of the large ceramic tile of thickness 4 [mm]. Can be mentioned.

(2) The width 1.2 [mm] x length 3 [mm] above is a large thickness ceramic plate which almost completely eliminates the defects of the softening property, and thus the height direction of the first floor of a high-rise building is as follows. Since they can be glued together in one sheet, the economical effect that the construction cost of the wall is considerably cheaper can be obtained.

(3) The present invention is different from the conventional concrete panels, and since it is excellent in water resistance, it does not need to attach a waterproof layer and is light in weight with a thin thickness of 4 [mm]. Since the weight can be reduced to pillars, bridges, and foundations, the economic effect of the entire building is enormous.

Claims (5)

30-70 wt% of acicular crystal mineral β-CaOSiO ₂ in anhydrous conversion and 70-30 wt% of general porcelain containing clay and talc in anhydrous form Wherein the acicular crystal minerals are uniformly aligned in the same direction and shaped into a required shape, and the acicular crystal minerals are sintered in a temperature range of 1000 to 1250 [° C.]. It has a large flat plate sintered body. A raw material containing a needle crystal of β-CaO · SiO ₂ , having a needle crystal having a length of 1 mm or more and having an aspect ratio of 20 or more in anhydrous conversion of 30 to 70% by weight and a plastic clay material 60 to 30 [% by weight] in terms of anhydrous, 10 to 20 [% by weight] of talc as a hydrophobic lubricant of the orientation improving material, and 0 to 30 [ Weight percent] and add it to 100%, add water, pour water to make water content 14-20 [wt%], adjust to homogenize, and extrude the plasticized state into a cylindrical shape by a vacuum mill apparatus. Then, it is cut out and expanded to form a plate shape, and the plate-shaped dough of the desired thickness and size is made by using a rolling roller in the same direction as the extrusion direction. Needle-like, characterized in that the sintering in the temperature range of 1000~1250 ℃ crystal mineral method of producing a large plate-shaped sintered body having an ordered organization directed in the same direction and then viscous. The method of claim 2, The vacuum mill apparatus has an extrusion pressure of 15 to 30 [kg / cm &lt; 2 &gt; at the outlet, and the shaft and the bearing for supporting the inner bead of the clasp composed of the outer body and the inner bead in the vacuum mill are The inner bead is insulated from the rotation of the main screw shaft, and the inner bead is freely rotated and displaced by the flow resistance of the clay, thereby improving the orientation of the needle crystal in the clay and automatically adjusting the thickness of the cylindrical shaped body. A method for producing a large flat plate-shaped sintered compact in which needle-like minerals, which are cut and expanded in the form of a dough, are formed in a flat plate shape and rolled in the same direction as the extrusion direction, have a structure in which the needle crystal minerals are aligned in the same direction. The method of claim 3, Since the method of rolling the molded dough using a rolling roller restores the curved alignment structure caused by the rotation of the main screw of the vacuum mill, the spiral groove is rolled while applying reverse twisting. After being rolled by a pair of rollers having a large flat plate-shaped sintered body having a structure in which the acicular crystal minerals are oriented and aligned in the same direction, which are rolled on a plate-shaped dough having a desired thickness and size through several rolling steps. Manufacturing method. A main screw housed in a similar cylindrical outer body for conveying the clay, an electric motor for rotating the shaft of the main screw, and a hopper provided at the upper end of the similar cylindrical outer body for feeding the clay into the main screw; And a vacuum chamber provided on the similar cylindrical outer body, an inner bead supporting shaft and an inner bead, and a vacuum mill having a clasp for extruding the clay which excludes air from the vacuum chamber, wherein the main screw shaft and the inner are provided. An inner bead bearing case is provided at the junction of the bead supporting shaft to prevent the immersion of clay, and an inner bead bearing containing a thrust bearing with rigid insulation is provided inside the inner bead bearing case. The shaft and internal beads move flexibly along the flow of the clay so that the needle crystals contained in the clay are not resisted in the same direction. A device for producing a large flat plate-shaped sintered compact in which the needle-shaped crystal mineral having a structure aligned in the same direction is oriented.