JP2006181902A - Manufacturing method of resin product and molding apparatus for resin product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the nozzle forming part of a molding die, which is used for fabricating a nozzle hole even smaller than the conventional one and correspondingly is thin and fragile, from causing the fall in durability and breakages, and to make the manufacturing apparatus less expensive compared with the conventional expensive injection molding machine or excimer laser apparatus. <P>SOLUTION: The resin product is manufactured by the press process and the electrical discharge process. In the press process the molding face of the die member, on which a (conductive) projection having a sharp tip is arranged, is brought into contact with and pressed against a substrate which is held on a conductive holding stand and consists of an insulating resin composition containing a thermoplastic resin, while the substrate is heated. In the electrical discharge process the substrate is bored by causing the electrical discharge to generate between the holding stand and the projection when the holding face holding the substrate on the holding stand and the tip of the projection of the die member reach a predetermined distance. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resin product manufacturing method and a resin product molding apparatus.

  In recent years, there has been an increasing demand for fine processing in all fields. Among them, there is a demand for a technique for providing fine holes in a film-like or thin-plate-like resin for the purpose of generating fine droplets. For example, an ink jet recording head generally includes a fine ink discharge port (orifice), an ink flow path, and a discharge energy generating element provided in a part of the ink flow path. The ink discharge port forms a nozzle with a taper portion communicating with the ink flow path, and a nozzle plate arranged on a plate is called a nozzle plate.

  As a method of forming this nozzle, a punch having a shape corresponding to the taper shape of the nozzle and a die having a chamfered portion in a hole slightly larger than the narrow diameter portion at the tip of the punch are combined to penetrate the nozzle plate. (See, for example, Patent Document 1).

  In addition, in an ink jet recording head in which a chamber plate having nozzles and ink chambers is manufactured by injecting resin into the mold, an abutting mold made of an elastic member is brought into contact with the nozzle hole forming portion of the mold. In addition, there is a method of injection molding (see, for example, Patent Document 2).

On the other hand, the conventional molding method is used to form a nozzle hole in a non-penetrated state where a thin film remains or a state where burrs remain, and the excimer laser processing apparatus removes the thin film, burrs, etc. There is also a method of performing construction.
Japanese Patent Laid-Open No. 5-229127 (page 3, FIG. 5-6) JP 2000-71459 A (3rd page, FIG. 5)

  However, the orifice of the ink jet recording head has a diameter of several hundreds μm or less, usually about 50 μm. However, there is a demand for smaller orifices for higher quality recording, and the diameter of each orifice is the same. In order to keep the liquid discharge direction constant, there is a strict requirement that there should be no burrs or notches at the outlet of the orifice. It was accompanied by the difficulty that the machines and technology were sophisticated and expensive.

  For example, the problem in Patent Document 1 is that if the accuracy of the position of the punch and the die is not strictly controlled, the narrow diameter portion at the tip of the punch breaks and is difficult for production. Further, for example, one of the problems in Patent Document 2 is that when the mold of the elastic member and the nozzle hole forming portion of the opposite mold are in contact with each other, a gap is not generated between the two molds. Since it is necessary to give pressure that elastically deforms where the nozzle hole formation part hits, the damage to the mold is early, and it is necessary to manufacture the mold each time it is damaged. It becomes complicated. Another problem is that even when the orifice is made smaller than 50 μm, for example, 10 μm, the abutting with the elastic member needs to be pressed with a certain pressure in the same manner as described above, and becomes thinner and more fragile than before. It is feared that the nozzle forming part is damaged. Furthermore, in general, an injection molding machine is large in size and complicated in operation. When the nozzle hole is about 10 μm, it becomes difficult for the resin to flow into the details. There is concern about damage.

  In addition, the excimer laser processing apparatus used for the additional work is expensive, and the production cost is high because the energy consumption is very large.

  The present invention has been made in view of the above circumstances, and its purpose is to prevent mold defects even when molding is repeated over a long period of time, and to provide an injection molding machine, an excimer laser processing apparatus, and the like. An object of the present invention is to provide a resin product manufacturing method and a resin product molding apparatus capable of providing a resin product in which fine holes are formed, such as an ink jet recording head nozzle, without involving large-scale equipment.

In order to solve the above-described problems, in the present invention, as described in claim 1, the insulating substrate made of a resin composition containing a thermoplastic resin, which is held on a conductive holding stand. A pressing step of pressing the molding surface of the mold member on which the conductive protrusion having a sharp tip is disposed while heating the substrate and the mold member;
When the substrate is press-contacted by the molding surface of the mold member, and the distance between the holding surface of the holding table that holds the substrate and the tip of the protrusion of the mold member is a predetermined distance, And a discharging step of perforating the substrate by discharging between the protrusions.

Moreover, in the present invention, as described in claim 2, an apparatus for molding an insulating resin product comprising a resin composition containing a thermoplastic resin,
A holding table having a conductive holding surface for holding an insulating substrate made of a resin composition containing a thermoplastic resin;
A mold member having a molding surface in which a conductive protrusion having a sharp tip is disposed on the side facing the holding surface;
Heating means for heating the substrate and the mold member held by the holding table;
A pressing means for pressing the molding surface of the mold member against the substrate held by the holding table;
Discharging means for discharging between the protrusion and the holding surface;
An apparatus for molding a resin product, comprising: a control unit that discharges the discharge unit to perforate the substrate when a distance between the holding surface and the tip of the projection reaches a predetermined distance. Constitute.

  Also, in the present invention, as described in claim 3, the control means is such that the distance between the holding surface and the tip of the protrusion is 1/10 or less of the thickness of the substrate, and the holding surface. 3. The resin product molding apparatus according to claim 2, wherein the discharge means discharges when the tip and the tip of the protrusion are not in contact with each other.

  According to the invention described in claim 1 or 2, when the distance between the holding surface for holding the substrate and the tip of the protrusion of the mold member becomes a predetermined distance, the discharge is generated between the holding base and the protrusion. Since the substrate is perforated and the holding surface does not touch the tip of the fine protrusion of the mold member, even if molding is repeated over a long period of time, the fine protrusion of the mold member may be damaged. Absent.

  In addition, since it is not necessary to press the mold member against the holding surface of the substrate, an imprint molding machine that does not require high pressure can be used as the molding apparatus. The use of the imprint molding machine is generally a mold transfer in the sense of a transfer technique using a mold, and there is no conventional use for the fine perforation processing to which the present invention is directed. Since the imprint molding machine is small, easy to operate, and inexpensive compared to an injection molding machine and an excimer laser processing apparatus, it is possible to reduce the manufacturing cost.

  According to the invention described in claim 3, since it is not necessary to make the insulation treatment of the discharge device used for perforation by discharge and the molding device attached thereto large, the molding device does not become large and expensive. Therefore, it becomes possible to perforate without return and burr.

  The present invention will be specifically described with reference to an example of manufacturing the nozzle plate 104 in the ink jet recording head as shown in FIG. A plurality of orifices 106 serving as ink discharge ports are provided in one inkjet recording head. An example of a cross section around one of the orifices is shown in FIG. In FIG. 2, a nozzle plate 104 having nozzles 103 each having a tapered portion 105 and an orifice portion 106 corresponding to the position of each ink flow channel 102 is provided on the end surface of the head base 101 forming the ink flow channel 102. Is glued. An ink discharge energy generating element such as a piezoelectric element not shown in FIG. 2 changes the volume inside the ink flow path 102 abruptly, on the paper surface facing the ink jet recording head through the nozzle 103 provided in the nozzle plate 104, etc. Ink droplets are ejected onto the surface.

  A schematic view of a molding apparatus for producing the nozzle plate 104 is shown in FIG. The board | substrate 5 is a member before the shaping | molding used as a nozzle plate. The substrate 5 is made of a resin composition containing a thermoplastic resin that is insulative and needs to be softened when the tapered portion of the nozzle is formed, and can be softened by heating. For example, PET (polyethylene terephthalate), PMMA (polymethyl methacrylate), PC (polycarbonate), PE (polyethylene), PVC (polyvinyl chloride), and the like. In addition, the substrate 5 is processed in advance into a film shape. In this example, the thickness of the substrate is assumed to be in a range of approximately 0.1 mm to 0.5 mm. The substrate 5 is mounted on the holding surface of the conductive holding table 6 by vacuum suction. The holding base 6 becomes a mold on the orifice part 106 side shown in FIG. 2 when the nozzle plate is formed, and the holding surface is preferably flat.

  The molding surface of the mold member 1 serving as the upper mold is provided with conductive protrusions for forming the tapered portion 105 of FIG. 2 on the plane. The planar portion other than the protrusions of the mold member 1 is preferably a mirror surface because it is a mold that forms a surface on the tapered portion 105 side of the nozzle plate 104 to be bonded to the end surface of the head base 101 in FIG. Further, the projection of the mold member 1 is preferably conical because it forms the shape of the tapered portion of the nozzle plate 104, but is not limited to the conical shape as long as it is easy to release. Further, the tip of the protrusion of the mold member 1 preferably has a shape in which an electric field is concentrated so that a discharge position for perforation described later becomes one point, for example, a sharp pointed shape. Further, since the protrusion becomes a discharge electrode, the base material is conductive.

  As an example of the protrusion, a rod-shaped blank (φ high-speed steel, JIS G 4403) with a diameter of 0.3 mm and a length of 5 mm is about 100 μm long using a fine wire electric discharge machine dedicated to shaft processing, and the tip angle is about 20 degrees. Created a conical shape. A hole having a diameter of φ0.3 mm and a depth of 5.5 mm perpendicular to the surface of the mold member 1 serving as a mold plane is provided, and this is used as a protrusion member mounting hole. Insert the projecting member until the conical part of the projecting part protrudes from the mold plane, screw the projecting member fixing screw into the screw hole that penetrates the projecting member insertion hole on the side of the mold, and insert the projection into the mold at the tip of this screw The mold member 1 is fixed vertically by tightening the member. In addition, although the mold member 1 and the holding stand 6 use carbon tool steel SK13 in this example, it is not limited to this.

  The 1st plate 7 is being fixed to the press stand 14, and the 2nd plate 2 is being fixed to the press mechanism 3 which moves up and down. The press mechanism 3 can be lowered, stopped, and raised by an external signal as well as manually. The first plate 7 is heated by the first heat source 10, and the substrate 5 is heated to a high temperature via the holding table 6. Simultaneously with the heating by the first heat source 10, the second plate 2 is heated by the second heat source 8 and the mold member 1 is heated to a high temperature. In order to efficiently heat the substrate 5 and the mold member 1, it is preferable to provide a heat insulating material such as ceramic at an appropriate portion of the molding apparatus.

  Moreover, the thermocouple which is a temperature sensor is provided in each of the holding stand 6 and the mold member 1, and the mold member 1 and the substrate 5 are combined by combining the first heat source 10 and the second heat source 8 and a temperature controller separately provided. This device has a temperature adjustment function that can set the temperature independently. This temperature adjustment function is not essential, but by setting the temperature of the mold member 1 and the substrate 5 with high accuracy, the molding condition can be easily set and molding can be performed more stably. Is preferred.

  The temperature of the substrate 5 is preferably set to be slightly lower than the glass transition temperature of the resin composition of the substrate 5 because it is preferable that the shape of the substrate 5 is maintained at the time of molding and the protrusion easily enters. For example, it is preferable to set the temperature to be about 5 ° C. to 20 ° C. lower than the glass transition temperature. The temperature of the mold member 1 is such that when the mold member 1 is lowered and touches the substrate 5, the tip of the projection having a small heat capacity is cooled to a temperature not lower than the glass transition temperature. It is preferable to set the temperature range so as not to be fused. When the substrate 5 has a clear melting temperature as a characteristic of the resin composition, the temperature at which the fusion is not performed is preferably about 50 ° C. to 100 ° C. lower than the melting temperature. When the substrate 5 does not have a clear melting temperature, the temperature of the mold member 1 may be determined by experiment.

  Next, molding is started by the press mechanism 3 while the substrate 5 and the mold member 1 are at the desired temperatures as described above. The press mechanism 3 is provided with a height detection sensor 4 that measures the height from the holding surface of the holding table 6 to the tip of the protrusion of the mold member 1, and this value is defined as a height Lo. Here, the height Lo is input to the discharge control unit 13, compared with a height Lp that is input in advance, and at which the discharge starts, a stop signal that causes the press mechanism 3 to stop the mold member 1 at the time of matching. And then a discharge start signal is output to the discharge device 12. The height Lp is the distance from the holding surface 6 to the tip of the projection of the mold member 1 when the substrate 5 is perforated by electric discharge. The height Lp is 1/10 or less of the thickness of the substrate 5 and the holding surface and the tip of the projection are It is a predetermined value within a range of 0 or more (not including 0) in a non-contact state.

  The press mechanism 3 that has received the stop signal from the discharge control unit 13 stops the lowering of the mold member 1, and the discharge device 12 that has received the discharge start signal has the preset voltage and the tip of the protrusion of the mold member 1. Then, the substrate 5 is interposed between the holder 6 and the discharge. The anode terminal which is the discharge electrode terminal of the discharge device 12 is originally connected to the protrusion, but is attached to the electrically conductive mold member 1 which is easily connected and electrically connected, and the ground terminal is the holding base. 6 is connected. The mold member 1 and the holding base 6 are insulated by using Teflon (registered trademark) or the like so that they are not electrically connected except for the electrodes of the anode terminal and the ground terminal of the discharge device 12. The theoretical value of the discharge voltage to be set can be easily obtained from the product of the dielectric breakdown strength of the substrate 5 and the height Lp. In actual setting, it is preferable to set a value about 20% higher than the obtained value in order to provide a margin for the drilling energy by electric discharge.

  By the way, the discharge voltage actually set has an upper limit naturally depending on the ability of the discharge device 12 to be used, and as the voltage is increased, the discharge device itself is larger and more expensive. For example, it is necessary to strengthen the withstand voltage in the molding apparatus, and the entire molding apparatus including the discharge apparatus is large and expensive. Therefore, it is preferable to determine the height Lp at the time of discharge so that the discharge voltage does not become excessively high.

  It is presumed that the substrate 5 is perforated by discharge under the above-described conditions as follows. First, the projection of the mold member 1 is pushed into the substrate 5 by the press mechanism 3, and the portion of the pushed substrate 5 is pushed out from the projection toward the periphery, so that the substrate 5 includes the projection of the mold member 1. The surface is transferred. Further, by applying this discharge energy, the portion of the substrate 5 existing between the tip of the projection of the mold member 1 and the holding surface starts to be perforated by sublimation or combustion from the vicinity of the discharge center, and the range expands outward. This completes the drilling. Since it is presumed that combustion is included in the perforation, the surrounding atmosphere is preferably air or an oxygen concentration equivalent to 20% or higher.

  In the substrate 5, the diameter of the hole is changed by changing the material, the discharge voltage, and the discharge distance at the height Lp. If the material and thickness of the substrate 5 are the same, the hole diameter that can be drilled increases when the discharge voltage is increased or the discharge start distance Lp is shortened. A desired hole diameter can be drilled by adjusting the discharge voltage and the discharge distance according to the material of the substrate 5 and its thickness.

  After the discharge is completed, the temperature of the substrate 5 is lower than the glass transition temperature and is not deformed when taken out, and the temperature of the mold member 1 is also lower than the glass transition temperature of the substrate 5. Raise and release. This temperature will be referred to as the mold release temperature. The mold release temperature may be lower than the glass transition temperature, but is preferably approximately 30 ° C. to 40 ° C. in consideration of handling. After completion of the mold release, the vacuum suction is stopped and the molded substrate 5 is taken out. At the time of mold release, the first heat source 10 and the second heat source 8 may be stopped and natural cooling may be performed according to the ambient temperature of the apparatus. However, the first cooling source 11 and the second cooling plate 2 are respectively provided on the first plate 7 and the second plate 2. It is preferable to provide a cooling source 9 to forcibly cool the mold member 1 and the holding table 6. By doing so, the mold member 1 and the substrate 5 can reach the mold release temperature more quickly, and the substrate 5 that has been molded can be taken out more quickly. In this example, the first plate 7 and the second plate 2 are forcibly cooled by water cooling.

  Thus, a resin product with desired perforations is manufactured. Specific examples are shown below.

(Example 1)
When PET having a glass transition temperature of 79 ° C. and a thickness of 0.1 mm was used for the substrate 5, the temperature of the substrate 5 was set to 70 ° C., and the temperature of the mold member 1 was set to 100 ° C. by experiment. The discharge height Lp is set to 10 μm, which is 1/10 of the thickness of the substrate, and the dielectric breakdown strength of PET is 40 to 60 kV / mm. Assuming 600V as a dielectric breakdown voltage, the set discharge voltage was set to 800V so that the perforation by discharge can be performed reliably. The mold release temperature was set to 40 ° C. in consideration of handling because the glass transition temperature was lower than 79 ° C.

  This PET was pressed and discharged by the mold member 1 to form a nozzle having an orifice portion and a taper portion. Then, this operation was repeated and molding was performed 100 times. At any time, about 10 μm perforation could be satisfactorily performed, and there was no damage in the mold member 1 and the holding table 6 as the mold.

(Example 2)
When PMMA having a glass transition temperature of 120 ° C. and a thickness of 0.5 m was used for the substrate 5, the temperature of the substrate 5 was set to 100 ° C., and the temperature of the mold member 1 was set to 150 ° C. by experiment. The discharge height Lp is set to 20 μm, which is 1/10 or less of the thickness of the substrate, and the dielectric breakdown strength of PET is 20 kV / mm, so the dielectric breakdown voltage is calculated to be 400V. The set discharge voltage was set to 500 V so that perforation by discharge can be surely performed. The mold release temperature was set to 40 ° C. in consideration of handling because the glass transition temperature was lower than 120 ° C.

  The PMMA was pressed and discharged by the mold member 1 to form a nozzle having an orifice portion and a taper portion. Then, this operation was repeated and molding was performed 100 times. At any time, about 20 μm perforation could be satisfactorily performed, and there was no damage in the mold member 1 and the holding table 6 that were the molds.

  The temperature mentioned above is the temperature of the mold member 1 and the substrate 5 itself. In an actual apparatus, a thermocouple that is a temperature sensor is often difficult to attach to a site to be originally measured for convenience of installation, and the same applies to this example. Therefore, in parallel with the temperature measurement by the thermocouple, the temperature at the original position is measured by another means, for example, a radiation thermometer, and the relationship between the temperature measured by the thermocouple and the originally desired temperature is obtained. The set temperature value for the temperature regulator was corrected so that the temperature would be the temperature to be adjusted.

  In the above example, the substrate 5 has one perforation. When a plurality of perforations are provided, the necessary number of protrusions may be arranged. In this case, since discharge is required, an insulating material is arranged between the protrusions to form the mold member 1, and the connection between the electrical connection terminal taken out from each protrusion and the anode terminal of the discharge device 12 is sequentially switched. What is necessary is just to discharge. In addition, when the number of protrusions is one, the holding table 6 may be moved as a moving table with a necessary pitch between holes, and the molding and the discharge may be sequentially repeated as many times as necessary.

  In addition, this invention is not limited to said Example, A deformation | transformation in the range which does not deviate from the main point is possible.

1 is a perspective view illustrating an example of an appearance of an ink jet recording head. It is a figure which shows an example of the cross section of the orifice part periphery of an inkjet recording head. It is a conceptual diagram explaining an example of the manufacturing apparatus of the resin product of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Head base 102 Ink flow path 103 Nozzle 104 Nozzle plate 105 Tapered part 106 Orifice part 107 Adhesive layer 1 Mold member 2 2nd plate 3 Press mechanism 4 Height detection sensor 5 Board | substrate 6 Holding stand 7 1st plate 8 2nd heat source 9 2nd cooling source 10 1st heat source 11 1st cooling source 12 Discharge device 13 Discharge control part 14 Press stand

Claims (3)

With respect to an insulating substrate made of a resin composition containing a thermoplastic resin, which is held on a conductive holding base, a molding surface of a mold member in which a conductive protrusion having a sharp tip is disposed is used as the substrate. And a pressing step for pressing the mold member while heating,
When the substrate is press-contacted by the molding surface of the mold member, and the distance between the holding surface of the holding table that holds the substrate and the tip of the protrusion of the mold member is a predetermined distance, And a discharging step of perforating the substrate by discharging between the protrusions. An apparatus for molding an insulating resin product comprising a resin composition containing a thermoplastic resin,
A holding table having a conductive holding surface for holding an insulating substrate made of a resin composition containing a thermoplastic resin;
A mold member having a molding surface in which a conductive protrusion having a sharp tip is disposed on the side facing the holding surface;
Heating means for heating the substrate and the mold member held by the holding table;
A pressing means for pressing the molding surface of the mold member against the substrate held by the holding table;
Discharging means for discharging between the protrusion and the holding surface;
An apparatus for molding a resin product, comprising: a control unit that discharges the discharge unit to perforate the substrate when a distance between the holding surface and the tip of the projection reaches a predetermined distance. The control means includes the discharge means when a distance between the holding surface and the tip of the protrusion is 1/10 or less of a thickness of the substrate, and the holding surface and the tip of the protrusion are not in contact with each other. The resin product molding apparatus according to claim 2, wherein the resin product is discharged.

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