JP2020006601A - Mold cleaning device, mold cleaning method, resin molding apparatus, and manufacturing method of resin molded article - Google Patents

Abstract

To provide a mold cleaning device capable of removing a deposit adhered to a mold while suppressing damage to coating of the mold.SOLUTION: A mold cleaning device 10 is a device removing a deposit A adhered to a surface of a mold 25 on at least a part of which coating CT is conducted. The mold cleaning device 10 has a laser beam irradiation part (laser beam irradiation mechanism) 11 irradiating the mold 25 with a pulse laser beam, and the laser beam irradiation mechanism 11 has a laser beam moving part 12 moving the mechanism to the mold so that scanning laser power density per 1 sec. becomes 2 to 15 W/cm. Alternatively a mold cleaning device 10 has a laser beam irradiation part 11 irradiating the mold 25 with a pulse laser beam with laser fluence per 1 pulse of 0.04 to 0.7 J/cm, and the laser irradiation mechanism 11 has laser beam moving part 12 moving the mechanism to the mold 25 so that overlap rate of neighboring pulse laser beams becomes 85% or more.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an apparatus for cleaning a mold of a resin molding apparatus, a method for cleaning a mold, a resin molding apparatus, and a method for manufacturing a resin molded article.

  When resin molding is performed using a molding die in a resin molding device, a small amount of resin or the like adheres to and remains on the surface of the molding die even after the molded product is taken out. Gradually increases. When resin molding is performed in a state where such attached matter is attached to the surface of the mold, the shape of the attached matter may be transferred to the resin molded product.

  Therefore, cleaning for removing the deposits is periodically performed on the mold. In Patent Document 1, by irradiating a pulsed laser beam to the mold, the resin is thermally decomposed at the interface between the resin-containing substance and the surface of the mold, which adhered in a film form to the surface of the mold, It is described that the deposit is peeled off from the surface of the mold.

JP 2004-230750 A

  The surface of the mold is usually provided with a coating made of chromium or the like, and it is necessary to prevent the coating from being damaged when removing deposits. In Patent Literature 1, the molding die is irradiated with the pulse laser beam on the condition that the adhered substance is a film covering almost the entire cavity surface of the molding die. If it becomes large until it becomes a film covering, the amount of transfer to the resin molded article increases. Therefore, it is required to perform cleaning at a stage before the deposit becomes a film covering almost the entire cavity surface. At this stage, it is assumed that the film-like deposit covering almost the entire cavity surface is removed. Irradiation of the pulsed laser beam on the mold under the conditions described above may damage the coating.

  The problem to be solved by the present invention is to provide a mold cleaning apparatus and a mold cleaning method capable of removing the deposits attached to the mold while suppressing damage to the coating of the mold, and the mold cleaning apparatus. And a method of manufacturing a resin molded product using the method of cleaning a molding die.

A mold cleaning apparatus according to the present invention made in order to solve the above-described problem is an apparatus that removes deposits attached to a surface of a mold that has been coated at least in part,
A laser beam irradiation mechanism for irradiating the molding die with a pulsed laser beam,
The laser beam irradiation mechanism includes a laser beam moving unit that moves the laser beam with respect to the mold so that a scanning laser power density per ^second is ² to 15 W / cm ² .

In the present invention, the “scanning laser power density per second” means the energy of a laser (unit: J (joule) = Wsec (unit: cm ² ) applied to a unit area (unit: cm ² ) for a unit time (unit: sec (second)). Watt seconds)), and the unit is J / (cm ² sec) = Wsec / (cm ² sec), that is, expressed in W / cm ² . The scanning laser power density per second is the average output of the irradiated laser beam, the area derived from the distance that the spot of the laser beam moves relative to the mold and the width of the spot per second. And the area of one spot (the part irradiated to the initial position before movement) can be calculated by dividing the area by the sum of the area and the area of the laser beam per second. Is the output per unit area in the portion irradiated while moving).

The mold cleaning method according to the present invention is a method for removing the deposits attached to the mold at least partially coated,
The method is characterized in that a pulsed laser beam is irradiated on the mold while moving it with respect to the mold so that the scanning laser power density per ^second is ² to 15 W / cm ² .

  A resin molding apparatus according to the present invention includes a molding die having at least a portion of which is coated, and the above-described molding die cleaning device.

  A method for manufacturing a resin molded product according to the present invention is characterized in that after performing the mold cleaning method, a resin molded product is manufactured using the molding die.

  ADVANTAGE OF THE INVENTION According to this invention, the attachment which adhered to the molding die can be removed, suppressing the damage given to the coating of a molding die.

Molding mold (a) after cleaning and resin molding has not yet been performed, and resin cleaning 200 times (b), 400 times (c), 600 times (d) and 800 times (e), respectively, after cleaning An electron micrograph of the surface of the mold after the molding. FIG. 1 is a schematic configuration diagram showing an embodiment of a mold cleaning device and a resin molding device having the same according to the present invention. FIG. 2 is an enlarged view of a molding die and its vicinity in the resin molding device of the present embodiment. FIG. 4 is a conceptual diagram showing that a laser beam reciprocates in an X direction and a Y direction by a laser beam moving unit. FIG. 3A is a diagram showing an operation during resin molding in the resin molding apparatus of the present embodiment, showing a state in which a lead frame is placed on a lower mold and a resin material is supplied to a lower mold pot, FIG. 4B shows a state in which the resin material is supplied to the cavity by being tightened. FIG. 2A is a diagram showing the overlap of rectangular spots temporally adjacent to each other with respect to a pulse laser beam, and FIG. 2B is a diagram showing how the spots move in the X direction. FIG. 5 is a diagram showing a state in which a spot of a pulsed laser beam moves in a zigzag manner. FIG. 7A is a diagram showing overlapping of circular spots temporally adjacent to each other with respect to a pulsed laser beam, and FIG. 7B is a diagram showing how the spot moves in the X direction. FIG. 3 is a diagram showing an example of a beam irradiation intensity distribution in a cross section perpendicular to a pulse laser beam, showing a Gaussian distribution (a) and a top-hat type distribution (b). FIG. 4 is a diagram showing a locus of a laser beam on the surface of a lower die or an upper die (thin solid line), and a boundary (thick broken line) of a region irradiated with the laser beam when the laser beam moves zigzag once. Schematic diagram (a) showing a state where plasma is generated near the surface of the mold by irradiating the mold with a pulsed laser beam, and the plasma is heated by repeatedly irradiating the pulsed laser beam to the plasma. FIG. 3B is a schematic diagram showing a state in which the deposit is vaporized. FIG. 3A is a top view and FIG. 3B is a longitudinal sectional view illustrating an example in which a shielding unit is used. Another example of the trajectory of the laser beam on the surface of the lower mold or the upper mold, an example of repeated one-way movement in the irradiation area (a), and an example of moving the entire surface of the lower mold or the upper mold in a zigzag shape ( FIG. FIG. 4 is a schematic diagram showing another example of a laser beam moving unit. The schematic block diagram which shows an example of the resin molding unit which consists of several modules, such as a molding module. FIG. 3 is a schematic configuration diagram showing a state in which a molding die cleaning device is carried into one of the molding modules in the resin molding unit. The schematic block diagram which shows the other example of the resin molding unit which consists of several modules.

In the mold cleaning apparatus and method according to the present invention, by irradiating the mold while moving the pulse laser beam so that the scanning laser power density per second is 2 W / cm ² or more, at least a part of the coating The plasma can be heated to a temperature equal to or higher than a temperature at which various types of deposits are vaporized, while generating plasma on the deposits attached to the surface of the molding die subjected to the treatment. Thereby, the deposit is heated to a temperature equal to or higher than the temperature at which the deposit is vaporized and vaporized, and is removed from the surface of the mold.

On the other hand, the present inventor examined the formation process of the deposit by observing the surface of the mold in order to obtain knowledge on the damage that the pulsed laser beam might give to the coating of the mold. Obviously, instead of adhering to the surface in the form of a film covering almost the entire surface of the cavity from the beginning, it adheres in a point-like manner at first, and then gradually approaches the shape of a film covering almost the entire surface of the cavity. (The letter A is attached to the electron micrograph of FIG. 1 to indicate the attached matter). Therefore, when the pulsed laser beam is irradiated under the condition that the attached matter is in the form of a film covering almost the entire surface of the cavity surface, the gap between the attached matter (point-like or insufficiently enlarged area) If there is an unattached portion), the pulsed laser beam is directly irradiated on the coating, which may damage the coating. Therefore, in the mold cleaning apparatus and method according to the present invention, by setting the scanning laser power density per second to 15 W / cm ² or less, a pulse laser beam is directly applied to a coating used in a normal mold. Even if it is done, the damage to the coating can be suppressed. In the mold cleaning apparatus and method according to the present invention, the material of the coating of the mold is not particularly limited.

  Since the coating of the mold is in direct contact with the mold, the heat received by the plasma from the plasma is immediately transmitted to the mold and the attached matter, or radiated (radiated) from the surface of the coating. Since the heat capacity of the mold is sufficiently larger than that of the coating, the rise in temperature can be suppressed. Further, the heat conducted from the coating to the deposit does not affect the coating because the deposit is vaporized. For the above reasons, the effect of heat from the plasma on the coating is small.

In the mold cleaning apparatus and method according to the present invention, it is desirable that the laser fluence per pulse of the pulsed laser beam be 0.04 J / cm ² or more. Further, in the mold cleaning apparatus and method according to the present invention, it is desirable that the overlap ratio (described later) of adjacent pulse laser beams is 85% or more. By taking one or both of these configurations, it is possible to generate plasma on the adhered matter adhered to the surface of the mold, and to heat the plasma to a temperature higher than the temperature at which various kinds of adhered matter are vaporized. Can be.

  Here, the “overlap rate” is defined as the ratio of the volume of a portion overlapping with a pulse laser beam generated adjacently to the volume occupied by one pulse laser beam in the space where plasma is generated. If two adjacent pulsed laser beams are parallel, the overlap rate is determined by the pulse lasers generated adjacent to each other in the cross section perpendicular to that of one pulsed laser beam at an arbitrary position in the space where the plasma is generated. It can be determined by the ratio of the area of the portion overlapping the cross section perpendicular to that of the beam. The reciprocal of the overlap rate corresponds to the number of times of the pulse laser beam applied to the same location. If the pulse laser beam is not moved, the overlap ratio is 100%. However, in the present invention, since the pulse laser beam is moved, the overlap ratio is less than 100%.

Further, the overlapping ratio of adjacent pulsed laser beam after having the the same manner as above 85%, by a laser fluence per pulse of the pulsed laser beam and 0.7 J / cm ² or less, used in a conventional mold Even if a pulsed laser beam is directly applied to the coating being applied, damage to the coating can be suppressed.

  In the case of using the pulse laser beam and the beam moving mechanism, in order to more reliably remove the resin from the surface of the mold, and to further suppress damage to the coating made of chromium nitride or hard chrome, the pulse width is set to 1 to Desirably, 200 nsec.

In the mold cleaning apparatus and method according to the present invention, in order to more reliably remove deposits from the surface of the mold and further suppress damage to a coating made of chromium nitride or hard chromium, a pulse laser beam 1 The laser fluence per pulse is 0.1 to 0.6 J / cm ² , the pulse width is 50 to 120 nsec, the overlap rate is 90% or more and less than 100%, and the scanning laser power density per ^second is 3 to 11 W / cm ² desirable.

Alternatively, in the mold cleaning apparatus and method according to the present invention, the laser fluence per pulse of the pulsed laser beam is 0.04 to 0.1 J / cm ² , the pulse width is 50 to 120 nsec, and the overlap ratio is 98% or more and less than 100%. , even when the scanning laser power density is per a 5~11W / cm ² 1 sec, and more reliably remove deposits from the surface of the mold, and, the damage experienced by the coating of chromium nitride or hard chrome More can be suppressed.

  In the case where the pulse laser beam and the beam moving mechanism are used, the spot shape of the laser beam is rectangular (rectangular, square), and the beam moving mechanism moves the spot in parallel to a side of the rectangle. Desirably. This makes it possible to irradiate the surface of the mold with the pulsed laser beam so as to be evenly close to each other, and it is possible to clean the surface of the mold under conditions close to the same conditions while suppressing variations due to positions. Alternatively, the spot shape of the laser beam may be circular or annular. In this case, it is not necessary to adjust the direction in which the spot is moved to the shape of the spot, and the surface of the mold can be cleaned in a state close to the same condition while suppressing variation due to the position. These laser beam spot shapes can be similarly applied to the mold cleaning method according to the present invention.

In the mold cleaning device having the laser beam moving unit, the laser beam moving unit,
Reciprocating the pulse laser beam in a first direction with respect to the molding die;
Each time the pulsed laser beam is moved one way in the first direction, the pulsed laser beam is moved in a second direction perpendicular to the first direction by one spot of the spot irradiated with the pulsed laser beam on the mold. Can only be moved. In this case, between the laser beam moving part and the mold, a shielding part for shielding one portion of the spot at both ends of the reciprocating movement in the first direction can be provided. With this shielding portion, when the pulse laser beam moves in the second direction at the both ends, the pulse laser beam that is excessively irradiated as compared with a position other than the both ends is shielded, whereby the surface of the molding die is shielded. Cleaning can be performed with higher uniformity. The same applies to the mold cleaning method according to the present invention.

  Hereinafter, more specific embodiments of the molding die cleaning device, the molding die cleaning method, the resin molding device, and the resin molded product manufacturing method according to the present invention will be described with reference to FIGS.

(1) Configuration of the Mold Cleaning Device and the Resin Molding Device of the Present Embodiment As shown in FIG. 2, the mold cleaning device 10 of the present embodiment is a part of the components of the resin molding device 1 of the present embodiment. is there. The resin molding device 1 has a resin molding unit 20 together with the mold cleaning device 10.

  First, the configuration of the resin molding section 20 will be described. In the present embodiment, the resin molding section 20 is an apparatus that performs transfer molding, and includes a base 211 and four (two shown in FIG. 2) tie bars 212 erected on the base 211. A movable platen 221 held by the tie bar 212 so as to be movable up and down, a fixed platen 222 fixed to the upper end of the tie bar 212, and a toggle link 213 provided on the base 211 for moving the movable platen 221 up and down. And Between the upper surface of the movable platen 221 and the lower surface of the fixed platen 222, a molding die 25 provided with an upper die (first die) 251 and a lower die (second die) 252 facing each other is arranged.

  FIG. 3 shows the molding die 25 and its vicinity in an enlarged manner. Two cavities C are formed side by side on the lower surface of the upper mold 251, and two cavities C are formed on the upper surface of the lower mold 252. The lower surface of the upper die 251, the upper surface of the lower die 252, and the surfaces of the upper die 251 and the lower die 252 surrounding each cavity C are coated with chromium nitride coating CT. Instead of chromium nitride, another material such as hard chromium may be used for the coating CT. In the present embodiment, the cavity has a rectangular parallelepiped shape, but may have a cylindrical shape or the like depending on the shape of the resin molded product to be manufactured.

  Each of the upper surfaces of the lower mold 252 around the two cavities C of the lower mold 252 can receive the lead frame L thereon. Note that a substrate or the like may be placed on the upper surface of the lower mold 252 instead of the lead frame L.

  Between the two cavities C of the lower mold 252, a pot 2521 for storing the resin material and a plunger 2522 for extruding the resin material from the pot 2521 are provided. The two cavities C of the lower mold 252 are connected to the pot 2521 by runners 2523, which are passages through which the softened or molten resin material passes, as described later. A cull block 2511 is provided between the two cavities C of the upper mold 251 and at a position facing the pot 2521. Each of the two cavities C of the upper mold 251 is connected to a space directly below the cull block 2511 by a runner 2513.

  In the upper mold 251 and the lower mold 252, a heater (not shown) for maintaining the lead frame L and the resin material at a predetermined temperature during resin molding is built.

  The molding die cleaning device 10 includes a pulse laser light source 111, a laser beam moving unit 12, and an optical fiber 13 as a laser beam irradiation unit (laser beam irradiation mechanism) 11. Further, the mold cleaning device 10 has an upside-down inversion mechanism (not shown) for inverting the laser beam moving unit 12 upside down. Further, the molding die cleaning device 10 disposes the laser beam moving unit 12 outside the use position disposed between the upper die 251 and the lower die 252 and the space between the upper die 251 and the lower die 252. And a mold cleaning device moving mechanism (not shown) for moving the cleaning device in the Y direction (horizontal direction in FIG. 2) between the standby positions. The pulse laser light source 111 is always arranged outside the space.

Pulsed laser light source 111 is in the range scanned laser power density per second of 2~15W / cm ^2, within the laser fluence is 0.04~0.7J / cm ² per pulse, the pulse width is 1~200nsec A pulse laser beam B having a pulse repetition frequency within a range of 300 kHz to 10 MHz is emitted. In this embodiment, the pulse laser beam B is shaped and emitted so that the shape (spot shape) in a cross section perpendicular to the pulse laser beam B becomes a square. The cross-sectional shape of the pulse laser beam B may be rectangular, circular, or annular. The range (size) of the spot is defined by the 1 / e ² method (86% method). The spot size can be measured with an Ophir or Coherent camera beam profiler. Further, using a power meter manufactured by Ophir or Coherent, the average output of the laser beam is obtained, and the scanning laser power density per second can be obtained from the spot size and the average output of the laser beam. The laser fluence per pulse is a value obtained by dividing the above average output of the laser beam by the pulse repetition frequency. The pulse width can be measured using an oscilloscope manufactured by Agilent Technologies. The average output of the laser beam can be obtained by the formula of “average output of laser beam [W] = pulse energy [J] × pulse repetition frequency [Hz]”.

  The laser beam moving unit 12 includes a galvano scan head 121 and a lens 122. The galvano scan head 121 emits the pulse laser beam B introduced from the pulse laser light source 111 so as to reciprocate repeatedly in the X direction (the direction perpendicular to the plane of FIG. 2) and the Y direction (FIG. 4). The lens 122 adjusts the direction of the pulse laser beam B so that the reciprocating pulse laser beam B is emitted in the same direction regardless of the position. The pulse laser beam B emitted from the laser beam moving unit 12 is incident on one of the upper mold 251 and the lower mold 252 according to the direction of the laser beam moving unit 12 determined by the upside down mechanism. In the examples shown in FIGS. 2 and 4, the lens 122 is disposed after the galvano scan head 121, but the lens 122 may be disposed before the galvano scan head 121.

  The optical fiber 13 connects the pulse laser light source 111 and the laser beam moving unit 12, and the pulse laser beam B is introduced into the laser beam moving unit 12 through the optical fiber 13. Thus, the pulsed laser light source 111 can be arranged outside the space between the upper mold 251 and the lower mold 252 irrespective of the position of the laser beam moving unit 12. Since the upper mold 251 and the lower mold 252 are heated by the heater in the resin molding process, the space between the upper mold 251 and the lower mold 252 is at a high temperature for a while after the resin molding process is completed. ing. By arranging the pulse laser light source 111 outside the space between the upper mold 251 and the lower mold 252 as described above, when the elapsed time from the end of the resin molding process is short, the components of the pulse laser light source 111 Damage caused by heat received by the heat sink can be suppressed.

  When the width in the X direction of the upper mold 251 and the lower mold 252 is wider than the moving range of the pulse laser beam B in the X direction and / or the Y direction by the laser beam moving unit 12, the forming mold cleaning device moving mechanism includes: The laser beam moving unit 12 is moved between the use position and the standby position as described above, and is moved in the X direction and / or the Y direction in the space between the upper die 251 and the lower die 252. Used. For example, a servomotor, an air cylinder, or the like can be used as a mold cleaning device moving mechanism.

  The molding die cleaning device 10 includes, in addition to the components described above, a vaporized adhering matter removing unit that sucks gas in a space between the upper die 251 and the lower die 252 and discharges the gas to the outside of the resin molding device 1; It may have a vaporized adhering matter collecting filter (both not shown) attached to the adhering matter removing section.

(2) Operations of the Mold Cleaning Device and the Resin Molding Device of the Present Embodiment, and the Mold Cleaning Method and the Resin Molding Method of the Present Embodiment Operations of the Mold Cleaning Device 10 and the Resin Molding Device 1 of the Embodiment, and The molding die cleaning method and the resin molding method of the embodiment will be described. Hereinafter, first, an operation at the time of resin molding (excluding an operation of cleaning the molding die) by the resin molding unit 20 in the resin molding device 1 will be described. Next, an operation of the molding die cleaning device 10 in the resin molding device 1 will be described. Will be described. The operation of the mold cleaning device 10 corresponds to an embodiment of the mold cleaning method according to the present invention. A combination of the operation of the resin molding section 20 and the operation of the mold cleaning device 10 corresponds to an embodiment of the resin molding method according to the present invention.

(2-1) Operation at the time of resin molding by the resin molding section 20 The operation at the time of manufacturing a resin molded article by the resin molding section 20 will be described with reference to FIG. When manufacturing a resin molded product, the laser beam moving unit 12 is moved to the standby position in advance by the mold cleaning device moving mechanism. The standby position is a position outside the space between the upper mold 251 and the lower mold 252 as described above, and the operation of the resin molding unit 20 at the time of manufacturing a resin molded product is not hindered by the mold cleaning device 10. Absent.

  First, by lowering the movable platen 221, the upper mold 251 and the lower mold 252 are opened vertically (FIG. 5A). In this state, the lead frame L on which the electronic component is mounted on the upper surface and the lower surface is placed on the upper surface of the lower mold 252 such that the position of the electronic component and the cavity C in the horizontal direction are aligned. Further, a tablet-shaped resin material P is supplied into the pot 2521 by a resin material supply mechanism (not shown). The resin material P is a composite material containing, for example, a thermosetting resin (for example, an epoxy resin). The resin material P may contain a wax (such as a higher fatty acid ester), a curing accelerator (such as a phosphorus-based catalyst or an amino-based catalyst), a coupling agent, a coloring agent, a flame retardant, or a flame retardant auxiliary. . The resin material supply mechanism is widely used in a conventional resin molding apparatus, and a detailed description is omitted. The thermosetting resin in the resin material P is softened or melted in the pot 2521 by heat supplied from a heater provided in the lower mold 252. The upper mold 251 is also heated to a predetermined temperature by the heater.

  When the thermosetting resin in the pot 2521 is softened or melted, the movable platen 221 is raised by the toggle link 213 (FIG. 5B). Accordingly, the lower mold 252 on the movable platen 221 contacts the upper mold 251 and pushes the upper mold 251, and the upper mold 251 is fixed to the fixed platen 222, so that the mold 25 is clamped. By raising the plunger 2522 in this state, the resin material P in the pot 2521 is supplied to the cavities C of the upper mold 251 and the lower mold 252 through the runners 2513 and 2523. After a lapse of a predetermined time, the thermosetting resin in the resin material P is cured, and a resin molded product in which the resin is molded on the lead frame L is obtained. Thereafter, the movable platen 221 is lowered by the toggle link 213 to open the mold 25, and the resin molded product is removed from the mold 25.

  By repeatedly performing the above operations, a large number of resin molded products can be manufactured continuously (continuous molding). However, the deposit gradually adheres to the surface of the molding die 25 during repeated production of the resin molded product. The deposit attached to the molding die 25 contains any material or component contained in the resin material P or the lead frame L (or the substrate or the like). Further, deposits may adhere to the resin passage such as the parting surface (the lower surface of the upper die 251 and the upper surface of the lower die 252), an air vent (not shown), and a runner 2523, which may hinder continuous molding. There is. Therefore, the surface of the molding die 25 is cleaned by operating the molding die cleaning device 10 as described below every time a predetermined number of resin molded products are manufactured or every predetermined time.

(2-2) Operation of the Mold Cleaning Device 10 First, in a state where the mold 25 is open, the laser beam moving unit 12 is moved to the use position, that is, the upper mold 251 and the lower mold by the mold cleaning device moving mechanism. 252 (see FIG. 2). At this time, the vertical direction of the laser beam moving unit 12 may be in any state, and depending on the state, one of the upper mold 251 and the lower mold 252 is cleaned first. Hereinafter, a case where the lower mold 252 is cleaned will be described as an example.

  In this state, the pulse laser light source 111 emits the pulse laser beam B having the above-described laser fluence and pulse width per pulse at the above-described pulse repetition frequency. At that time, the laser beam moving unit 12 repeatedly moves the pulse laser beam B back and forth in the X direction. Thus, on the surface of the lower mold 252, the spot BS of the pulse laser beam B moves in the X direction within a predetermined range (a range between XL and XR in FIG. 4, which is referred to as a "predetermined range in the X direction"). (FIGS. 6A and 6B). In addition, every time the spot BS moves once in one direction in the X direction, the laser beam moving unit 12 sets a predetermined range of one spot BS in the Y direction (the range between YT and YB in FIG. 4). "The predetermined range in the Y direction"). By these operations, on the surface of the lower mold 252, the spot BS moves in the X direction by a predetermined range in the X direction (FIGS. 6 (a), (b), and FIG. 7). The zigzag movement of moving in the X direction and then moving in the X direction in the opposite direction to the previous direction is repeated within a predetermined range in the Y direction (FIG. 7).

  Here, the speed at which the pulse laser beam B moves in the X direction is determined by the fact that the square spot of the pulse laser beam B on the surface of the lower die 252 is less than 1/6 of one side per one cycle of the pulse. The speed of movement. As a result, 85% or more of the spots of two pulse laser beams B that are temporally adjacent to each other overlap (the overlap rate is 85% or more and less than 100%). The same position is irradiated with the pulse laser beam B six times or more. FIG. 6A shows an example of spots BS1 and BS2 of two pulse laser beams B that are temporally adjacent to each other. In this figure, the area of the portion BSW where the spot BS1 and the spot BS2 overlap (the area shown with a diagonal hatch in the figure) is 85% or more of the area of the spot BS1 (the same applies to the spot BS2). Has become. When the spot is moved in the X direction at the overlap rate shown in FIG. 6, the result is as shown in FIG. The speed at which the pulsed laser beam B moves in the X direction may be different from the speed at which the pulsed laser beam B moves in the Y direction.

  6 (a) and 6 (b) exemplify a case where the spot diameter is rectangular, but the spot diameter is circular (FIGS. 8 (a) and 8 (b)) and an annular (ring) shape. The same applies to other shapes such as (FIGS. 8C and 8D).

  The distribution of the irradiation intensity in the cross section of the beam in the direction perpendicular to the pulsed laser beam B is generally a Gaussian distribution having the maximum at the center (FIG. 9A), but the upper mold 251 and the lower mold 252 are used. In order to clean the surface substantially uniformly, it is desirable to have a top-hat type distribution (FIG. 9B) having a substantially equal distribution from the center to the end. Further, it is desirable to increase the depth of focus so that the focal position does not need to be changed in accordance with the step on the surface.

  As described above, the spot of the pulse laser beam B moves in a zigzag manner on the surface of the lower mold 252, so that the pulse laser beam B is irradiated onto a part or the entire area of the surface of the lower mold 252 without leakage. Here, when the pulse laser beam B is irradiated only on a part of the surface of the lower mold 252, after the irradiation of the pulse laser beam B by one zigzag movement is completed, the moving mechanism of the molding die cleaning device moves the laser beam. The moving unit 12 is moved to a position on the surface of the lower mold 252 that has not been irradiated with the pulse laser beam B yet. Then, in the same manner as described above, the pulse laser beam B is applied to the area while moving it in a zigzag manner. By repeating the above operation, the entire surface of the lower mold 252 is irradiated with the pulse laser beam B. FIG. 10 illustrates the locus of the zigzag of the pulse laser beam B on the surface of the lower mold 252 by a thin solid line, and the boundary of the irradiation area of the pulse laser beam B by one zigzag movement is illustrated by a thick broken line.

  After that, the laser beam moving unit 12 is turned upside down by the upside down mechanism, and the entire surface of the upper die 251 is irradiated with the pulse laser beam B as in the case of the lower die 252.

  In the mold cleaning device 10 of the present embodiment, the pulse laser beam B having the scanning laser power density per second and the laser fluence per pulse is applied to the surface of the mold 25 (the upper mold 251 and the lower mold 252). By the irradiation, the surface of the deposit A becomes high temperature and high pressure, and plasma PL is generated on the surface of the molding die 25 (FIG. 11A). The source of the plasma PL is not particularly limited, but the plasma PL can be generated by irradiating the pulsed laser beam B to the deposit. Then, the plasma PL is irradiated with the pulse laser beam B at the above-described scanning laser power density per second, or the overlap ratio of the above-described pulse laser beam B having the laser fluence per pulse becomes 85% or more. By irradiating the same location in the plasma PL six times or more by moving the pulse laser beam B as described above, the resin contained in the deposit A attached to the surface of the molding die 25 in normal resin molding is vaporized. The plasma PL is heated to a temperature at which the plasma PL is generated (FIG. 11B). Here, heat transferred or radiated from the coating CT heated by the plasma PL acts from below the attached matter A attached to the lower mold 252 (or above the attached matter A attached to the upper mold 251). Is also good. By heating the plasma PL in this way, at least a part of the deposit A on the surface of the mold 25 is vaporized and removed from the surface. It should be noted that both ends in the X direction of the range in which the pulse laser beam B moves are less than one width of the pulse laser beam B in the X direction (for example, when the overlap ratio is 85%, the width of the width is 17 times). In the part of (/ 20), the number of times of irradiation of the pulse laser beam B may be less than six times. However, the width is usually sufficiently small, and the plasma PL heated around the part flows into the part. Does not. The vaporized deposits AG are suctioned and removed from the vicinity of the surface of the molding die 25 when the mold cleaning device 10 has a vaporized deposit removal device.

  On the other hand, commonly used materials such as chromium nitride and hard chromium, coating CT made of a material in which microcracks are present and cracks proceed at a temperature lower than the melting point, and coating CT made of a multilayer film are generally used. In general, the thickness is about several μm to several tens μm, and the conventional method has a problem that it is easily peeled off. Even if such a coating CT is directly irradiated with the above-described scanning laser power density per second or a pulse laser beam B having a laser fluence per pulse, the damage to those coating CT is caused by the conventional laser beam. Is smaller than the case of the cleaning method using. Also, generally, since the mold contains a large number of metals such as iron, steel, stainless steel, and aluminum on the surface and inside, and is easier to dissipate heat than resin, heat transmitted from the plasma PL to the coating CT immediately ( It can be conducted or diffused into the mold 25 (instead of the deposit) or radiated (emitted) from the surface of the coating CT to suppress the influence on the coating CT.

  Further, in the mold cleaning apparatus 10 of the present embodiment, since the deposit A is removed by heating the plasma PL, it is not necessary to directly irradiate the pulse laser beam B to all the deposits A. Therefore, it is possible to easily remove the deposit A attached to a position where the pulse laser beam B is difficult to be irradiated, such as a side surface of the mold (for example, a side surface facing the cavity C).

On the other hand, if the scanning laser power density per ^{second is} less than ² W / cm ² , the scanning speed of the laser beam may be too high or the laser power density (without scanning) may be too low. Become. In this case, damage to the coating is suppressed, but it is difficult to remove the deposit. If the scanning laser power density per ^{second is} higher than 15 W / cm ² , the scanning speed of the laser beam is too slow or the laser power density is too high. When the scanning speed of the laser beam is too slow, although the cleaning can be performed, the time required for the cleaning is too long. If the laser power density is too high, it will be difficult to suppress damage to the coating.

If the laser fluence per pulse is less than 0.04 J / cm ^{2 and} the overlap ratio of adjacent pulsed laser beams is less than 85%, it is difficult to remove the deposit. When the laser fluence per pulse is larger than 0.7 J / cm ² , it becomes difficult to suppress damage to the coating.

  4 and the like, the pulse laser beam B is drawn so as to be perpendicular to the upper surface of the lower die 252. However, by adjusting the direction of the laser beam moving unit 12, the upper surface of the lower die 252 is adjusted. Irradiation may be performed in a direction inclined with respect to the direction (the same applies to the lower surface of the upper die 251). Thereby, the pulse laser beam B is also applied to the side wall surface and the like forming the cavity C in the upper mold 251 and the lower mold 252.

Next, an experiment was performed under a plurality of conditions in which the scanning laser power density per second of the pulsed laser beam B was different from each other, and it was confirmed whether the removal of the deposits and the effect on the coating were good. The deposit is generated when a normal resin molded product is manufactured. A coating made of chromium nitride was used. Table 1 shows the experimental results.
In Table 1, “○” indicates that no deposits remained on the surface of the mold and no damage to the coating was observed. A “△” indicates that either little deposits were left or slight damage was found in the coating, or both, but still acceptable for practical use. "X" indicates that only one or both of the deposits remained and the coating was found to be slightly damaged, which is not practically acceptable. From the above results, it can be said that the range of the scanning laser power density per second from ² to 15 W / cm ² is included in the present invention, and it is desirable that the range is from 3 to 11 W / cm ² .

(3) Other Embodiments of the Present Invention The present invention is not limited to the above embodiments. For example, when the spot BS of the pulse laser beam B moves on the lower surface of the upper die 251 or the upper surface of the lower die 252 along the path shown in FIG. 7, the X direction of the path (that is, the spot BS reciprocates). Direction, corresponding to the first direction) between the laser beam moving unit 12 and the upper mold 251 or the lower mold 252, and a shielding unit for shielding the pulse laser beam B by a width of one spot BS. 15 (indicated by a thick solid line in FIG. 12) can be provided. The shielding unit 15 may be provided both between the laser beam moving unit 12 and the upper mold 251 and between the laser beam moving unit 12 and the lower mold 252.

  In the portion where the shielding portion 15 is provided, the spot BS is moved in the Y direction (the second direction) without providing the shielding portion 15 and maintaining the emission of the pulse laser beam B from the pulse laser light source 111 as in the above-described embodiment. (Corresponding to the direction), the pulsed laser beam B is emitted with a larger number of pulses than in other parts, depending on the speed of the movement. For example, a portion serving as a starting point of irradiation or a portion where movement in the X direction and movement in the Y direction are switched may include a portion where the number of times of irradiation of the pulse laser beam B is different from other portions. The portion where the shielding portion 15 is provided is also a position where the number of times of irradiation with the pulse laser beam B can be less than six times as described above. On the other hand, the pulse laser beam B is shielded by the shielding portions 15 at both ends in the X direction by one spot BS, and cleaning is performed by the pulse laser beam B passing through the unshielded portion. Processing uniformity can be further improved.

  Instead of using the shielding unit 15, the emission of the pulse laser beam B from the pulse laser light source 111 may be stopped while the spot BS is moved in the Y direction. Further, the moving speed of the pulse laser beam may be changed, and the laser fluence and / or the repetition frequency per pulse may be changed accordingly. For example, by moving the laser beam faster, and thereby increasing the laser fluence per pulse and / or increasing the repetition frequency, the area that can be irradiated with the pulse laser beam in the same time can be expanded. it can.

  The spot BS is moved in one direction in the X direction (the path indicated by the thin solid line in the figure), for example, as shown in FIG. 13A, in addition to the zigzag movement as shown in FIG. 7 and FIG. Then, the emission of the pulsed laser beam B from the pulsed laser light source 111 is stopped, and the spot is moved by one spot BS in the Y direction while returning to the initial position in the X direction (the path indicated by the thin broken line in the figure). The operation of moving one way in the X direction may be repeated. Alternatively, as shown in FIG. 13B, one zigzag movement (or one-way repetitive movement in FIG. 13A) can be applied to the entire cleaning target (without dividing into a plurality of irradiation areas as described above). The pulse laser beam B may be applied.

  FIG. 14 shows another example of the laser beam irradiation unit. The laser beam irradiation unit 11A includes a pulse laser light source 111, a laser beam moving unit 12A, a lens 122A, an optical fiber 13, an X-direction rail 161, an X-direction belt 162, a belt attachment member 163, and an X-direction It has a motor 164, an X-direction pulley 165, a motor block 166, a pulley block 167, and a Y-direction rail 168.

  The pulse laser light source 111 is disposed outside the space between the upper mold 251 and the lower mold 252 in the same manner as described above, and is connected to the laser beam moving unit 12A via the optical fiber 13. The laser beam moving unit 12A is disposed in the space at the time of cleaning, and irradiates the pulse laser beam B from the pulse laser light source 111 upward or downward, and does not have a galvano scan head. The lens 122A is fixed to the side of the laser beam moving unit 12A from which the pulse laser beam B is emitted, and irradiates the upper mold 251 or the lower mold 252 by narrowing the diameter of the pulse laser beam B from the laser beam moving unit 12A. It is.

  The X-direction rail 161 is a rail that extends in the X direction immediately below the upper mold 251 or directly above the lower mold 252 so as to cross the molds. The laser beam moving unit 12A is provided movably in the X direction along the X direction rail 161. An X-direction belt 162 is attached to the laser beam moving unit 12A by a belt attaching member 163. The X-direction motor 164 is housed in a motor block 166, and the motor block 166 is fixed to one end of the X-direction rail 161. The X-direction pulley 165 is housed in a pulley block 167, and the pulley block 167 is fixed to the other end of the X-direction rail 161. The X-direction belt 162 is hung on an X-direction motor 164 and an X-direction pulley 165, and a part of the X-direction belt 162 is attached to the laser beam moving unit 12A by a belt attachment member 163. With these configurations, when the X-direction motor 164 rotates in either direction, the X-direction belt 162 moves in either the positive or negative direction of the X direction, and accordingly, the laser beam moving unit 12A moves along the X-direction rail 161. Move.

  The Y-direction rail 168 is a pair of rails extending in the Y direction provided so as to sandwich the upper die 251 or the lower die 252 in the X direction. The motor block 166 and the pulley block 167 are provided movably in the Y direction along the Y direction rail 168. At both ends of the Y-direction rail 168 on the motor block 166 side, a Y-direction motor and a Y-direction pulley are provided, and the Y-direction motor and the Y-direction pulley are covered with a Y-direction belt. Are attached to the motor block 166 (not shown). Thus, the motor block 166 moves along the Y-direction rail 168 when the Y-direction motor rotates, as in the case where the laser beam moving unit 12A moves in the X-direction. When the motor block 166 moves in this manner, the X-direction rail 161 and the laser beam moving unit 12A also move in the Y direction. The Y-direction motor, the Y-direction pulley, and the Y-direction belt may be provided on the pulley block 167 side.

  X-direction rail 161, X-direction belt 162, belt mounting member 163, X-direction motor 164, X-direction pulley 165, motor block 166, pulley block 167, Y-direction rail 168, Y-direction motor, Y-direction pulley described above. And the Y-direction belt correspond to a laser beam moving unit.

  The laser beam irradiation unit 11A moves in the Y direction by one spot of the pulse laser beam B along the Y direction rail 168 each time the laser beam moving unit 12A moves one way in the X direction along the X direction rail 161. This operation is repeated by reciprocating the laser beam moving unit 12A in the X direction, thereby irradiating the upper die 251 or the lower die 252 with the pulse laser beam B in a zigzag manner (see FIG. 13B).

  FIG. 15 shows a configuration of a resin molding unit 30 including a plurality of sets of the resin molding units 20 and one set of the mold cleaning device 10. In this resin molding unit 30, one material receiving module 31, a plurality of molding modules 32, one dispensing module 33, and one molding die cleaning device standby module 34 are arranged in a row. The material receiving module 31 is a device for receiving the tablet-shaped resin material P and the lead frame L from the outside and sending them to the molding module 32, and has a lead frame receiving section 311 and a tablet supply section 312. One molding module 32 has one resin molding unit 20 in the resin molding apparatus 1 of the above embodiment. Although three molding modules 32 are shown in FIG. 15, any number of molding modules 32 can be provided in the resin molding unit 30. Further, even after the resin molding unit 30 has been assembled and used, the number of molding modules 32 can be increased or decreased. The dispensing module 33 carries in and holds the resin molded product manufactured by the molding module 32 from the molding module 32, and has a resin molded product holding portion 331. The mold cleaning device standby module 34 accommodates the mold cleaning device 10 when not in use.

  The transfer device 35 carries the substrate and the resin material from the material receiving module 31 to the forming module 32 along the transfer rail provided in the resin forming unit 30 and discharges the formed resin molded product from the forming module 32. It is a device that is carried out to the module 33. Further, when cleaning the molding die in a certain molding module 32, the transport device 35 carries the molding die cleaning device 10 into the molding module 32 (FIG. 16), and after the cleaning of the molding die is completed. It also has a function to carry out the mold cleaning device 10 from the molding module 32.

  The resin molding unit 30 is suitable for mass-producing resin molded products because a plurality of molding modules 32 can produce resin molded products in parallel. At that time, a certain amount of time is required from mounting the substrate on the molding die to producing the resin molded article and then carrying out the molded article, so that a certain molding module 32 produces the resin molded article. By attaching the molding object to another molding module 32 or carrying out the resin molded product from another molding die, the production efficiency of the resin molded product can be increased, and the cost required for the transfer device can be suppressed. . Further, the molding die cleaning device 10 can be shared by a plurality of molding modules 32.

  In the resin molding unit 30, the molding die cleaning device standby module 34 arranged in the same row as the other modules is used. However, instead of the resin molding unit 30A shown in FIG. The mold cleaning device housing and moving module 34A extending along the line may be used. The configurations of the material receiving module 31, the molding module 32, and the dispensing module 33 in the resin molding unit 30A are the same as those of the resin molding unit 30. The mold cleaning device housing / moving module 34A has therein a mold cleaning device moving unit 35A that houses the mold cleaning device 10 and moves the mold cleaning device 10 in the direction in which other modules are arranged. As viewed from the resin molding unit 20 of each molding module 32, the molding die cleaning device housing / moving module 34A and the molding die cleaning device moving unit 35A therein are provided on the opposite side of the transport device 35. The operation of the resin molding unit 30A is the same as that of the resin molding unit 30 except that the molding die cleaning device moving unit 35A is used when the molding die cleaning device 10 is carried into and out of the molding module 32. .

  The present invention is not limited to the above embodiments, and various modifications are possible within the scope of the present invention.

For example, in the above embodiment, the laser fluence per pulse of the pulse laser beam is set to 0.04 to 0.7 J / cm ² , the pulse width is set to 1 to 200 nsec, and the overlap ratio of the adjacent pulse laser beams is set to 85% or more. However, depending on the material and amount of the deposit, or the material of the coating, even if the mold is irradiated with a pulsed laser beam with a laser fluence, pulse width or overlap ratio outside the above range, plasma may be generated on the deposit. In some cases, the plasma can be heated to a temperature higher than the temperature at which the deposits vaporize, and the irradiation intensity (laser fluence, laser power density) of the laser beam can be suppressed to a value lower than a value that damages the coating. .

In the above-described embodiment, the spot of the pulse laser beam is moved for each pulse, but may be moved for a plurality of pulses. In that case, it is preferable that the laser fluence be 0.04 to 0.7 J / cm ² per the plurality of pulses.

  Although the pulse laser beam is used in the above embodiment, a continuous laser beam that oscillates continuously may be used.

  In the above embodiment, the mold 25 for the transfer molding is used as the mold 25 of the resin molding section 20. However, the mold used in other molding methods such as compression molding and injection molding is also applicable to the molding die cleaning of the above embodiment. Apparatus 10 can be applied.

DESCRIPTION OF SYMBOLS 1 ... Resin molding apparatus 10 ... Mold cleaning apparatus 11, 11A ... Laser beam irradiation part (laser beam irradiation mechanism)
111 pulse laser light source 12, 12A laser beam moving section 121 galvano scan head 122, 122A lens 13 optical fiber 15 shielding section 161 X direction rail 162 X direction belt 163 belt attaching member 164 X direction Motor 165 ... X-direction pulley 166 ... Motor block 167 ... Pulley block 168 ... Y-direction rail 20 ... Resin molded part 211 ... Base 212 ... Tie bar 213 ... Toggle link 221 ... Movable platen 222 ... Fixed platen 25, 25A ... Molding die 251, 251A upper mold 2511 cul block 2513 runner 252, 252A lower mold 2521 pot 2522 plunger 2523 runner 30 resin molding unit 31 material receiving module 311 lead frame receiving unit 312 tablet supply unit 3 ... Molding module 33, dispensing module 331, resin molded article holding section 34, molding die cleaning apparatus standby module 34A, molding die cleaning apparatus housing / moving module 35, transport apparatus 35A, molding die cleaning apparatus moving section A, adhering substance AG, Vaporized deposit B: pulsed laser beam BS, BS1, BS2: spot of pulsed laser beam BSW: spot overlapping spot C: cavity CT: coating L: lead frame P: resin material PL: plasma

Claims (16)

An apparatus for removing deposits attached to the surface of a mold at least partially coated,
A laser beam irradiation mechanism for irradiating the molding die with a pulsed laser beam,
The molding die cleaning device, wherein the laser beam irradiation mechanism has a laser beam moving unit that moves the laser beam with respect to the molding die so that a scanning laser power density per ^second is ² to 15 W / cm ² . Mold cleaning according to claim 1, wherein the laser beam irradiation mechanism, laser fluence per pulse is equal to or a pulsed laser beam is 0.04~0.7J / cm ² is intended to be irradiated to the mold apparatus.   The said laser beam moving part moves the said pulse laser beam with respect to the said shaping | molding die so that the overlapping rate of an adjacent pulse laser beam may be 85% or more, The Claim 1 or 2 characterized by the above-mentioned. Mold cleaning device.   The mold cleaning apparatus according to claim 1, wherein a pulse width of the pulse laser beam is 1 to 200 nsec.   The molding according to any one of claims 1 to 4, wherein a cross-sectional shape of the laser beam is rectangular, and the laser beam moving unit moves the laser beam in parallel with a side of the rectangle. Mold cleaning device.   The mold cleaning apparatus according to any one of claims 1 to 4, wherein a sectional shape of the laser beam is circular or annular. The laser beam moving unit,
Reciprocating the pulse laser beam in a first direction with respect to the molding die;
Each time the pulsed laser beam is moved one way in the first direction, the pulsed laser beam is moved in a second direction perpendicular to the first direction by one spot of the spot irradiated with the pulsed laser beam on the mold. Only to move
Further, a shielding portion is provided between the laser beam moving portion and the molding die, the shielding portion shielding one portion of the spot at both ends of the reciprocating movement in the first direction. The mold cleaning device according to any one of the above. A method for removing deposits attached to a mold having at least a portion of a coating,
A method of cleaning a molding die, comprising irradiating a molding laser with a pulsed laser beam while moving the molding laser such that a scanning laser power density per ^second is ² to 15 W / cm ² . 9. The mold cleaning method according to claim 8, wherein a laser fluence per pulse of the pulse laser beam is 0.04 to 0.7 J / cm < ² >.   The molding die cleaning method according to claim 8 or 9, wherein the pulse laser beam is moved with respect to the molding die so that an overlap ratio of adjacent pulse laser beams is 85% or more.   The mold cleaning method according to any one of claims 8 to 10, wherein a pulse width of the pulse laser beam is 1 to 200 nsec.   The molding die cleaning method according to claim 8, wherein the laser beam has a rectangular cross-sectional shape, and the laser beam is moved in parallel with a side of the rectangle.   The mold cleaning method according to claim 8, wherein a sectional shape of the laser beam is circular or annular. When moving the pulse laser beam with respect to the mold,
Reciprocating the pulse laser beam in a first direction with respect to the molding die;
Each time the pulsed laser beam is moved one way in the first direction, the pulsed laser beam is moved in a second direction perpendicular to the first direction by one spot of the spot irradiated with the pulsed laser beam on the mold. Just move it,
The mold cleaning method according to any one of claims 8 to 13, wherein a portion corresponding to one spot at both ends of the reciprocating movement in the first direction is shielded from the laser beam.   A resin molding apparatus comprising: a molding die having at least a portion of which is coated; and the molding die cleaning device according to claim 1.   A method for manufacturing a resin molded product, comprising: performing a molding die cleaning method according to any one of claims 8 to 14 and then manufacturing a resin molded product using the molding die.