Electric heating – Metal heating – By arc
Reexamination Certificate
2000-05-18
2002-06-25
Elve, M. Alexandra (Department: 1725)
Electric heating
Metal heating
By arc
C219S121670, C219S121600, C219S121740
Reexamination Certificate
active
06410883
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a cleaning device and a cleaning method for cleaning a resin sealing metal mold, and in particular to a cleaning device for removing stains from a resin sealing metal mold using laser beams, and a cleaning method using this cleaning device.
DESCRIPTION OF THE RELATED ART
Resin sealing metal molds are usually used in manufacturing certain products by sealing IC, LSI, etc. with resin. The resin sealing metal molds need to be cleaned after being used in manufacturing certain number of products. Such cleaning is significant especially when the number of products is large, when the product appearances, etc. should be improved, and when the product's weatherbility should be maintained and improved.
Conventionally, cleaning a resin sealing metal mold would usually require cleaning processes by manpower. Consequently, a great deal of labor and hours for cleaning are needed. Such conditions lead to problems of increasing manhours and deteriorating productivity in a resin sealing process.
Under the circumstances, there has been a great expectation for a progress in a development of a cleaning device and a cleaning method capable of simplifying the cleaning operation of a resin sealing metal mold. It is expected that such device and method will reduce the manhours in the cleaning operation and the time for cleaning, thus realizing improved productivity.
For a prior art example, there is Japanese Patent Application Laid-Open Publication No. 10-255510 disclosing a front floodlight lens for vehicle. In more detail, the disclosure is about a front floodlight lens for vehicle, where a film mainly made of titanium oxide having a photo-medium function is formed. In Table 1 of the disclosure, under the condition that a front floodlight lens having its external surface coated with a film with a photo-medium function goes through irradiation with sunlight for five hours, light transmittance before and after the irradiation is measured to see the difference. Table 1 shows results of measurement of changes in the light transmittance of a deformed lens before and after the irradiation by sunlight, i.e. changes in the light transmittance of the lens before and after stains are decomposed by sunlight, being a light of 500 nm.
Furthermore, in the prior art reference, it is also mentioned that the front floodlight lens for vehicle is capable of photodecomposing stains on the deformed lens by ultraviolet rays to naturally maintain transparency of the lens, because it has the titanium oxide film with the photo-medium function effectively formed on the surface of the deformed lens.
In this way, the prior art reference shows that this deformed lens with a film formed thereon is capable of decomposing and removing stains on the lens, which gives an advantage that the front flood light can be kept in good condition with respect to its appearance and illuminance for a long time. However, such film as disclosed in the reference is effective for partially decomposing and removing stains of organic compounds only.
In the prior art reference, there is no disclosure about removing adhered stains of inorganic substance. Therefore, it should be difficult to completely clean complex stains including organic materials and inorganic substances. For example, a sealing material is a compound of organic materials such as an epoxy resin, etc., and inorganic materials such as a filler of silica, calcium oxide, etc. With respect to removing such complex stains, generally, it is far more difficult than the case of removing stains of organic substances. Likewise, cleaning of complex stains is difficult using the above-described cleaning method alone.
As for another prior art example, there is Japanese Patent Application Laid-Open Publication No. 1-122417 disclosing a cleaning method for cleaning a metal mold for molding synthetic resin. In accordance with this method, it is possible to remove the stains of organic substances and inorganic substances.
In this method, however, if a method as shown in
FIG. 3
of the reference is applied, it should take a long time, i.e. three to four hours, for completely removing the entire stains. Moreover, the time required for cleaning depends on a size and a degree of dirtiness of the metal mold, due to which improvement of productivity can not be expected.
The present invention has been achieved with the above aspects of the prior art in mind. In a resin used for a resin sealing, a variety of organic substances and inorganic substances are mixed, and therefore, the resin forming materials including a mixture of organic and inorganic substances tend to adhere to the surface of a metal mold for forming the resin sealing, every time the resin sealing is formed. This will result in an accumulation of stains.
In accordance with the above-described prior art methods, for instance, removing of stains is done using a photodecomposition effect of ultraviolet rays, which limits the decomposing subjects to organic substances.
Consequently, stains of inorganic substances are not decomposed but left accumulated inside the metal mold. It is therefore, unlikely to have the metal mold completely cleaned up inside. Furthermore, with respect to a sealing material made of a complex compound of organic and inorganic substances, cleaning effect will further decrease, which makes it more difficult to remove the stains.
SUMMARY OF THE INVENTION
It is therefore, an object of the present invention to provide a device for cleaning stains on a resin sealing metal mold in a short period of time, even when the stains are complex compounds of organic and inorganic substances, and a method using the device.
In accordance with the first aspect of the present invention, there is provided a cleaning device for cleaning a resin sealing metal mold comprising: a laser beam generating means; a first reflection means for reflecting a laser beam generated by the laser beam generating means; and a second reflection means for receiving the reflected laser beam from the first reflection means in order to irradiate the inner surface of said metal mold.
In accordance with a second aspect of the present invention, there is provided a leaning device for cleaning a resin sealing metal mold as mentioned in the first aspect, further comprising a rotation means for rotating said second reflection means.
In accordance with a third aspect of the present invention, there is provided a cleaning device for cleaning a resin sealing metal mold as mentioned in the first aspect, wherein said laser beam generating means is a pulse form laser generating means which applies the laser beam in pulses.
In accordance with a fourth aspect of the present invention, there is provided a cleaning device for cleaning a resin sealing metal mold as mentioned in the second aspect, wherein said laser beam generating means is a pulse form laser generating means which applies the laser beam in pulses.
In accordance with a fifth aspect of the present invention, there is provided a cleaning system comprising: a cleaning device for cleaning a resin sealing metal mold having a laser beam generating means, a first reflection means for reflecting a laser beam generated by the laser beam generating means, and a second reflection means for receiving the reflected laser beam from the first reflection means in order to irradiate the inner surface of said metal mold; and a resin sealing metal mold having a film with a photo-medium effect formed at least at one portion thereof.
In accordance with a sixth aspect of the present invention, there is provided a cleaning system comprising: a cleaning device for cleaning a resin sealing metal mold having a laser beam generating means, a first reflection means for reflecting a laser beam generated by the laser beam generating means, a second reflection means for receiving the reflected laser beam from the first reflection means in order to irradiate the inner surface of said metal mold, and a rotation means for rotating said second reflection means; and a resin sealing met
Elve M. Alexandra
Hutchins, Wheeler & Dittmar
NEC Corporation
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