JP6484777B2 - Ceramic black nozzle - Google Patents

Description

Detailed Description of the Invention

  The present invention relates to a ceramic black nozzle for adsorbing components, which is preferably used in an electronic component mounting machine for mounting electronic chip components such as a capacitor chip and a resistor chip on a circuit board.

  In recent years, in the field of circuit board mounting, development of electronic component mounting machines capable of mounting fine chip components at high speed and with high accuracy is progressing along with high integration and high accuracy of substrates. In this electronic component mounting machine, a nozzle that sucks and holds a chip component is attached to the tip of a vacuum suction head that sucks outside air, and the head portion reciprocates between a feeder portion and a circuit board. At this time, the chip component vacuum-sucked by the nozzle is mounted on the circuit board after determining the suction state of the chip part and the position of mounting the component by image analysis while the head unit moves between the feeder unit and the circuit board. Therefore, this image analysis is performed by irradiating light in the direction of the chip component and the suction surface from the front of the nozzle, and analyzing the shape of the chip component, the electrode position, and the like from the difference in the amount of reflected light.

  FIG. 2 is a schematic view showing an example of a mounting process of a chip component on a circuit board using the electronic component mounting machine.

  The electronic component mounting machine 10 shown in FIG. 2 includes a component suction nozzle 1 mounted at the tip of the head portion, a feeder tray 12 in which chip components 11 are arranged, and a chip component 11 sucked by the nozzle 1. A light 13 for irradiating light, a CCD camera 14 for receiving reflected light from the chip component 11, and an image analysis device 15 for processing the reflected light received by the CCD camera 14. Yes. Here, the component suction nozzle 1 has a suction surface 2 for sucking and holding an electronic component by vacuum suction as illustrated in FIG. 1, and communicates from the rear end to the suction surface. The suction hole 3 is formed in a portion including the cylindrical portion 4 from the nozzle rear end toward the tip, and a conical portion 5 having an inverted conical shape on the tip end side of the cylinder portion 4. The chip component 11 is sucked and held on the suction surface 2 by sucking outside air from the front end to the rear end.

  In the electronic component mounting machine 10, when the nozzle 1 moves to the tray 12 and sucks the chip components 11 arranged on the tray 12, the light 13 emits light toward the chip components 11 sucked by the nozzle 1. The reflected light that is irradiated and reflected when the light hits the main body of the chip component 11 is received by the CCD camera 14, and the deviation and position of the chip component 11 are measured by the image analysis device 15 based on the image received by the CCD camera 14. Based on the data, the nozzle 1 that adsorbs the chip component 11 is moved to a predetermined position on a circuit board (not shown), and the chip component 11 is mounted on the circuit board.

  By the way, in recent years, the miniaturization of chip parts has progressed with the high integration and high precision of circuit boards, but chip parts are blown away by static electricity because the chip parts are small and lightweight at this mounting site, Even if the chip part is released from suction, there are many troubles that it can be taken home without separation or malfunctions in image analysis. As countermeasures, the nozzle is made semiconductive to remove static electricity and the reflected light from the nozzle is removed as much as possible to increase the blackness of the nozzle or specify the surface roughness of the nozzle suction surface to obtain brightness ( A method of reducing the reflectance is taken.

  For example, as a semiconductive ceramic black nozzle, zirconia or alumina added with a conductivity-imparting material such as iron oxide or chromium oxide (Patent Document 1), and the surface roughness of the adsorption surface of the nozzle tip are specified. In addition, a device with reduced brightness (reflectance) (Patent Documents 2 to 5) has been proposed.

Japanese Patent No. 3261665 JP 2011-151306 A JP 2011-49551 A Japanese Patent Laid-Open No. 11-99426 JP-A-10-117099

  Among these, when iron oxide is used as the black conductivity imparting material, in addition to the essential problem of iron oxide that it is easily magnetized, a part of iron oxide at a low temperature of about 150 ° C. There are many problems such as thermal stability problem of oxidation to redness, and a large amount of addition required to obtain the desired blackness due to low blackness, resulting in reduced strength of the molded product Have a problem. In addition, chromium oxide is dark green and far from true black, and part of chromium oxide (trivalent) may change to extremely harmful hexavalent chromium oxide in the firing process, which may cause process contamination. At present, there are fatal problems in health and safety.

  On the other hand, in the method of specifying the average surface roughness (Ra) by a method such as polishing finishing on the suction surface at the tip of the nozzle, the average surface roughness (Ra) is a three-dimensional numerical representation of the irregularities on the surface of the object. Therefore, even if the average surface roughness (Ra) is the same, the reflected light flux varies depending on the color and material. Therefore, it is not always practical to judge the quality of image analysis based on the surface roughness. Also, with respect to luminance (reflectance), when light is irradiated from a specific direction on the nozzle, the reflected light flux is reflected by the luminance (reflectance) regardless of the light receiving direction in the case of perfect diffuse reflection where the nozzle surface is a standard white plate. ) Is constant, but since the luminance (reflectance) differs depending on the angle of light received by the black nozzle, management by luminance (reflectance) is practically difficult at the mounting site.

  In view of these circumstances, the present invention is suitable for an electronic component mounting machine that is less likely to cause troubles at the time of image analysis, such as blow-off and take-out of chip components, high mounting accuracy, and no risk of process contamination due to harmful substances. An object is to provide a ceramic black nozzle for adsorbing components used in manufacturing.

  In order to solve the above-mentioned problems, the present inventors have intensively studied an adsorption nozzle for chip parts by an image analysis method. As a result, a nozzle molded body obtained by adding titanium dioxide to partially stabilized zirconia is reduced and fired in the firing process. For example, the structural oxygen in titanium dioxide causes oxygen deficiency and changes from white to gray and blue-black to true black, and from insulating to conductive. By controlling the crystal grain size, oxygen deficiency, etc. of zirconia, it can be formed into a molded product that combines specific conductivity and deep blackness with less gloss, and this molded product can be used very favorably as a mounting nozzle. The present inventors have found out what can be done and have completed the present invention.

That is, the present invention relates to a ceramic black nozzle having an adsorption surface for adsorbing and holding an object to be adsorbed at the tip, and the zirconia having an average crystal particle diameter of 0.5 to 2.0 μm, wherein the ceramic black nozzle is partially stabilized. It contains 5 to 30 wt% of low-order titanium oxide having an average crystal particle size of 0.03 to 0.15 μm represented by TiOx (1.50 ≦ X ≦ 1.95) as a conductivity imparting material, and the nozzle A ceramic having a resistance value between 10 ^{3 and} 10 ¹⁰ Ω between the front end and the rear end of the glass and an L * value determined by a spectrocolorimeter based on JIS Z 8729 is 50 or less It relates to a black nozzle.

  According to the ceramic black nozzle of the present invention, a specific low-order titanium oxide is produced in partially stabilized zirconia, so that it has no magnetism, excellent strength and durability, and low gloss and deep blackness. Because it combines conductivity, when used as a chip component mounting nozzle, there are few problems such as blowout and take-out of chip components, troubles during image analysis, etc., high mounting accuracy, and processes due to harmful substances It has many excellent effects such as no fear of contamination.

(A) is a perspective view which shows one Embodiment of the ceramic black nozzles of this invention, (B) is the side surface sectional drawing. These are the schematic diagrams which show the structural example of the electronic component mounting apparatus which mounts a chip component on a circuit board using the electronic component mounting machine provided with the ceramic black nozzles of this invention.

  The present invention will be described in detail below.

In the ceramic black nozzle of the present invention, 5-30 wt% of TiO ₂ (titanium dioxide) is added as a conductivity-imparting material to zirconia having a partially stabilized average crystal particle diameter of 0.5 to 2.0 μm, and a binder is added thereto. And kneading by adding a molding aid and the like, and drying by a known method such as a spray dryer to produce a powder or granular raw material, which is then injection-molded to form a nozzle shape, removing the solvent, and reducing and firing. Thus, the TiO ₂ in the molded body was reduced in order, and TiOx (1.50 ≦ X ≦ 1.95) having an average crystal particle diameter of 0.03 to 0.15 μm was generated. A ceramic black nozzle having an electric resistance value between 10 ^{3 and} 10 ¹⁰ Ω and an L * value determined by a spectrocolorimeter based on JIS Z 8729 of 50 or less.

In the present invention, the zirconia partial stabilizer is preferably one of yttrium oxide (Y ₂ O ₃ ), magnesium oxide (MgO), calcium oxide (CaO), cerium oxide (CeO ₂ ), etc., among which yttrium oxide is preferable. preferable. The amount of yttrium oxide added is preferably 1 to 5 mol%. If the amount is less than 1 mol%, the amount of monoclinic zirconia increases, cracks occur frequently inside the sintered body, and the mechanical strength decreases. On the other hand, the addition of yttrium oxide If the amount exceeds 5 mol%, the amount of tetragonal zirconia will decrease, and in this case as well, excellent mechanical strength cannot be obtained.

  The crystal state of the partially stabilized zirconia, which is the main component of the ceramic black nozzle of the present invention, is preferably such that the amount of zirconia other than monoclinic crystals is 80% or more with respect to the total amount of zirconia obtained from X-ray diffraction. When the amount of zirconia other than oblique crystals is less than 80%, a stress-induced phase transformation function peculiar to zirconia cannot be expected, and excellent bending strength and fracture toughness cannot be obtained.

  Here, the stress-induced phase transformation of partially stabilized zirconia refers to the property that tetragonal zirconia in the crystalline state of zirconia undergoes stress-induced transformation due to external stress and undergoes phase transformation to monoclinic zirconia. Due to the volume expansion that occurs during the phase transformation from tetragonal to monoclinic crystals, minute microcracks are generated around the zirconia and the progress of external stress is prevented, so the bending strength and fracture toughness of the zirconia sintered body increase. It is.

  The zirconia used in the present invention has an average crystal particle size of 0.5 to 2.0 μm, preferably 0.5 to 1.5 μm. When the average crystal particle size is less than 0.5 μm, the above-described stress-induced phase transformation function is not sufficiently exhibited, so that excellent strength and fracture toughness cannot be obtained, and due to surface unevenness interaction with lower-order titanium oxide particles described later. Whereas excellent component adsorbing power and low gloss cannot be obtained, if the average crystal particle size is larger than 2.0 μm, mechanical properties such as wear resistance, impact resistance and bending strength are deteriorated.

  In the present invention, the average crystal particle diameter of zirconia and low-order titanium oxide is measured by mirror-finishing the sintered body, performing thermal etching, observing with a scanning electron microscope, and measuring from the average of 10 points by the intercept method. Ask. As a calculation formula, D = 1.5 × L / n [D: average crystal grain size (μm), L: measurement length (μm), n: number of crystals per length L] was used.

In the ceramic black nozzle of the present invention, low-order titanium oxide represented by TiOx (1.50 ≦ X ≦ 1.95) in which titanium dioxide is reduced as a conductivity-imparting material is added to the partially stabilized zirconia. 30 wt% is contained. The titanium dioxide used in the present invention may be in any of the rutile type, anatase type, or brookite type. These are inexpensive, non-magnetic, and are widely used as color pigments because they are excellent in safety and dispersibility. The average particle size of the low-order titanium oxide after firing can be appropriately adjusted so that the average crystal particle size is 0.03 to 0.15 μm.

  This titanium dioxide is white and insulating at room temperature, but when it is reduced and fired at high temperature, oxygen deficiency occurs, and the color becomes gray, blue-black, and true black, and the electrical conductivity increases. is there.

  As a reducing gas at the time of firing, one kind of hydrogen, nitrogen, argon, helium, or a mixed gas thereof is suitable, and in particular, a mixture of an inert gas such as nitrogen or argon and hydrogen of about 2 to 10 vol%. Reduction in gas is preferable in that the lowering of titanium dioxide proceeds efficiently. Moreover, you may bake in the reducing gas which coexists reducing agents, such as carbon and a hydrocarbon. The firing conditions are preferably 1200 to 1500 ° C. for 1 to 5 hours. If the firing temperature is less than 1200 ° C., the reduction efficiency of titanium oxide is poor, and the structural change to blackening or conductivity is difficult to proceed. A certain zirconia is insufficiently sintered, resulting in insufficient strength. On the other hand, when the firing temperature exceeds 1500 ° C., the grain growth of zirconia increases, and in this case as well, the strength must be reduced.

  In the ceramic black nozzle of the present invention, the low-order titanium oxide contained in the partially stabilized zirconia has an X value represented by TiOx of 1.50 to 1.95. That is, it is generally known that low-order titanium oxide has a maximum blackness with an X value of 0.2 to 1.95 and a conductivity with an X value of 1.75. However, in the present invention, the X value is 1.50 to 1.95, and when the X value is less than 1.50, the crystal is likely to change to a NaCl type structure, causing volume shrinkage and decreasing strength. Cause. On the other hand, if the X value exceeds 1.95, the blackness and conductivity are insufficient, and the target black semiconductive nozzle cannot be obtained.

  In the present invention, the amount of oxygen in the low-order titanium oxide, that is, the X value of TiOx is usually oxidized at a temperature of 500 to 600 ° C. to form titanium dioxide, and changes from black to white. Therefore, the black nozzle made of ceramic after reduction firing was subjected to thermal analysis (TG-DTA) at room temperature to 1000 ° C. in the atmosphere at a temperature rising rate of 20 ° C./min, and the weight increase during that time was oxygen accompanying oxidation The X value was calculated as the amount of increase.

The ceramic black nozzle of the present invention also has an average crystal particle size of the partially stabilized zirconia of 0.5 to 2.0 μm, whereas low-order titanium oxide is used in the raw material kneading, forming and firing steps. In consideration of secondary aggregation, particle growth, etc., it is necessary to set the average crystal particle size of 0.03 to 0.15 μm. If the average crystal particle size of the low-order titanium oxide is larger than 0.15 μm , the particle size difference from the partially stabilized zirconia crystal particles is small, the surface smoothness is high, and the separation property of the adsorbed chip parts deteriorates. In addition to the inconvenience that the frequency of taking home parts increases, it becomes difficult to cause irregular reflection of incident light, so that the glossiness of the nozzle surface is increased, and malfunction is easily caused in image analysis when chip parts are mounted. On the other hand, if the average crystal particle size of the low-order titanium oxide is less than 0.03 μm, the particle size difference from the crystal particles of the partially stabilized zirconia becomes large, air leaks during vacuum suction, and the adsorptive power decreases. There arises a problem that the mounting accuracy deteriorates due to frequent displacement and dropping of the chip parts.

The low-order titanium oxide of the present invention includes low-order titanium oxides such as Ti ₂ O ₃ , Ti ₃ O ₅ , Ti ₄ O ₇ , Ti ₅ O _9, etc. Those composed of sub-titanium oxide, those in which low-order titanium oxide and titanium dioxide are mixed, or those in which the degree of oxygen deficiency is different between the inside of the particle and the surface of the particle or in the vicinity thereof can be used. When the component composition is represented by the general formula TiOx, it is important that the X value is 1.50 to 1.95.

  In the present invention, the content of the low-order titanium oxide with respect to the partially stabilized zirconia is 5 to 30 wt%, preferably 8 to 25 wt%. When the content of the low-order titanium oxide is less than 5 wt%, the blackness and conductivity are low. On the other hand, when the content of low-order titanium oxide exceeds 30 wt%, the bending strength, fracture toughness, wear resistance, etc. of the nozzle deteriorate.

The ceramic black nozzle of the present invention contains a specific amount of the low-order titanium oxide, so that the electrical resistance value between the tip and the rear end of the nozzle is 10 ³ to 10 ¹⁰ Ω, preferably 10 ⁴ to 10 ^8. The L * value obtained with a spectrocolorimeter based on JIS Z 8729 is 50 or less, preferably 45 or less.

If the electrical resistance value between the front and rear ends of the nozzle is 10 ³ to 10 ¹⁰ Ω, even if static electricity is charged on the nozzle, this static electricity can be moderated through a nozzle holding component or electronic component mounting machine that conducts. Since the charge can be removed at a high speed, troubles such as blowout of chip parts due to charging of the nozzle and discharge breakdown can be prevented. That is, if the electrical resistance value between the tip and the rear end of the nozzle is less than 10 ³ Ω, the electrical conductivity is too high and the static electricity is removed at once. On the other hand, if the electrical resistance exceeds 10 ¹⁰ Ω, the static electricity generated in the nozzle will be charged, so that dust or the like will adhere to the electronic components, or if the nozzle approaches the chip components, The problem arises that the chip parts are blown away by the force.

  Further, the ceramic black nozzle of the present invention has an L * value of 50 or less measured by a spectrocolorimeter based on JIS Z 8729 as an index of blackness.

  The reason why the black nozzle is used in the electronic component mounting machine is that when the chip component adsorbed by the nozzle is irradiated with light and photographed with a CCD camera, the background of the chip component becomes dark when the nozzle is black. This is because the shape of the chip component adsorbed by the nozzle can be accurately recognized, and the positional accuracy when the chip component is mounted on the circuit board is increased. Therefore, in the present invention, when the L * value of the ceramic black nozzle exceeds 50, the brightness of the nozzle becomes high, and it becomes difficult to distinguish the nozzle from the chip component due to the reflected light, causing a recognition error or malfunction. In addition, this problem tends to become conspicuous as the chip is miniaturized or the mounting speed is increased.

  As described above, the ceramic black nozzle of the present invention specifies the crystal particle diameters of partially stabilized zirconia and low-order titanium oxide, and forms fine irregularities on the nozzle surface, so that the adsorbing power of an appropriate chip component can be increased. The surface glossiness is maintained, but as the number of times of mounting in the component mounting process increases to hundreds of thousands and millions of times, the nozzle suction surface wears out, and the resin component of the chip component is deposited on the suction surface. In order to reduce the frequency of these troubles, such as adhesion, resulting in a decrease in the component adsorption force and a reduction in mounting efficiency due to an increase in surface glossiness, at least the adsorption surface of the nozzle is preliminarily used by a well-known method as necessary. Needless to say, polishing or pretreatment such as blast treatment, DLC treatment, or silicate coating may be performed.

  In addition, the ceramic black nozzle of the present invention may contain known additives such as alumina, titanium nitride, and silicon carbide in addition to the partially stabilized zirconia and low-order titanium oxide, as long as the nozzle performance is not impaired. Processing may be performed.

  Hereinafter, in order to make the present invention easier to understand, description will be made based on examples, but the present invention is not limited to these examples.

(Examples 1-9, Comparative Examples 1-4)
Titanium dioxide with an average particle size of 0.07 μm was added in various proportions to partially stabilized zirconia with an average crystal particle size of 1.0 μm containing 3 mol% of yttrium oxide, and an acrylic or ethylene vinyl acetate binder and A compound material was prepared by adding waxes and kneading and drying. The compound material was injection molded under the conditions of a mold temperature of 40 ° C. and an extrusion temperature of 150 ° C. to obtain a nozzle-shaped molded product shown in FIG. The molded product is desorbed in the atmosphere at 450 to 900 ° C., and then fired in an inert gas containing argon as a main component at a temperature of 1100 ° C. to 1600 ° C. for 1 hour. Nozzle samples with different X values were prepared.

  About the obtained nozzle sample, bending strength, electroconductivity, blackness, a mounting defect rate, an electrostatic breakdown rate, a blow-off rate, etc. were evaluated and it put together in Table 1 with comprehensive evaluation.

  In this example, the X value, bending strength, conductivity, blackness, mounting failure rate, electrostatic breakdown rate, blow-off rate, and overall evaluation of TiOx were evaluated by the following methods.

  As described above, the X value of the low-order titanium oxide TiOx was determined by performing thermal analysis (TG-DTA) at normal temperature to 1000 ° C. with the nozzle after reduction firing in the atmosphere at a heating rate of 20 ° C./min. The X value was calculated with the increase in weight as the amount of oxygen increase accompanying oxidation.

  The bending strength is a four-point bending strength in accordance with JIS R1601 (2008) by grinding a sintered body produced with the same composition and manufacturing conditions as each sample to a test piece of 3 mm × 4 mm × 40 mm. Measured by the method.

  For conductivity, an electrode was brought into contact with the suction surface and the rear end surface of the nozzle tip, a voltage was applied by connecting a surface resistance measuring device between these electrodes, and the resistance value between the nozzle tip and the rear end was measured.

  For the blackness, the L * value of the nozzle surface was measured with a spectrocolorimeter based on JIS Z 8729, and the numerical value was used to determine the blackness. This L * value represents the brightness of the color, and the lower the value, the higher the blackness.

  For the mounting failure rate, each nozzle sample was attached to an electronic component mounting machine, and a chip component having a size of 0.6 mm × 0.3 mm (0603 type) was subjected to a mounting test. Counting the number of misalignment due to suction failure, part dropping, mispositioning due to image analysis failure, etc. at the time of 10,000 mounting, and the total mounting failure rate divided by 10,000 What was less than 0.05% was (◯), what was 0.05 to 0.5% was (Δ), and what was higher than 0.5% was (x).

  In addition, the electrostatic breakdown rate was obtained by mounting 100,000 chip parts on a substrate by the same method as described above and counting the number of electrostatic breakdowns by evaluation using a continuity tester. As a result, less than three chip parts that were electrostatically destroyed were indicated by (◯), 3-10 pieces were (Δ), and more than 10 pieces were electrostatically broken (×).

  The blow-off rate is similar to the above, when 100,000 chip parts are mounted on the substrate, the number of blown-out chip parts is less than 3 (◯), 3 to 10 (△), 10 A large number of electrostatic breakdowns were taken as (x).

  Comprehensive evaluation is based on a comprehensive judgment of bending strength, mounting failure rate, electrostatic breakdown rate, blow-off rate, etc. (○), which is extremely suitable as a component suction nozzle for electronic component mounting machines ( (△) and the unsuitable thing was set as (x).

  From the results of Table 1, the ceramic black nozzle of the present invention in which the content of low-order titanium oxide TiOx and its X value are within the scope of the present invention, and the conductivity and blackness (L * value) satisfy specific conditions. It is found that this is suitable as a component suction nozzle for an electronic component mounting machine because it has excellent mechanical strength, high mounting accuracy, and extremely low electrostatic breakdown rate and blow-off rate of components.

(Examples 10-16, Comparative Examples 5-8)
The same method as in Example 5 except that the average crystal particle size of partially stabilized zirconia was changed to 0.3 to 2.5 μm and the average crystal particle size of low-order titanium oxide was changed in the range of 0.02 to 0.35 μm. A nozzle sample was prepared. The low-order titanium oxide in these nozzle samples had an X value of 1.85 to 1.90, an electrical conductivity of 10 ⁵ Ω, and a blackness (L * value) of 30 to 35, respectively.

  The obtained nozzle samples were evaluated for bending strength, mounting failure rate, take-out rate, etc., and are summarized in Table 2 together with comprehensive evaluation.

  In Table 2, the take-out rate is the same as in the evaluation of the mounting failure rate, the mounting test is performed, the number of chip parts taken at the time of 10,000 mounting is counted, and the number is 10,000 (○) indicates that the take-out rate divided by 0.05 was less than 0.05%, (△) indicates that it was 0.05-0.5%, and (×) indicates that it was higher than 0.5%. did.

  The bending strength, mounting failure rate, and comprehensive evaluation in Table 2 were evaluated in the same manner as in Table 1.

  From the results of Table 2 above, those in which the average crystal particle sizes of partially stabilized zirconia and low-order titanium oxide are within the scope of the present invention are good in mechanical strength, mounting accuracy, and take-out rate, and are components of an electronic component mounting machine. It turns out that it is suitable as a nozzle for adsorption.

  The ceramic black nozzle of the present invention has excellent mechanical strength and high mounting accuracy, while chip components are being downsized and mounting speeds are increasing. Because of the advantage that mounting trouble is extremely small, it can be used in the field of chip component mounting where electronic chip components are sucked and held and mounted on a substrate.

DESCRIPTION OF SYMBOLS 1; Ceramics black nozzle 2; Suction surface 3; Suction port 4; Cylindrical part 5; Conical part 10; Electronic component mounting apparatus 11; Chip component 12; Tray 13;

Claims (1)

In a ceramic black nozzle having an adsorption surface for adsorbing and holding an object to be adsorbed at the tip, conductivity is imparted to zirconia having an average crystal particle diameter of 0.5 to 2.0 μm, in which the ceramic black nozzle is partially stabilized. The material contains 5 to 30 wt% of low-order titanium oxide having an average crystal particle size of 0.03 to 0.15 μm represented by TiOx (1.50 ≦ X ≦ 1.95), and the tip and rear ends of the nozzle A ceramic black nozzle characterized by having an electrical resistance value between 10 ^{3 and} 10 ¹⁰ Ω and an L * value determined by a spectrocolorimeter based on JIS Z 8729 of 50 or less.

Images