JPH06126256A - Processing apparatus and processing method using supercritical fluid - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a processing apparatus and a processing method using a supercritical fluid that has a small number of processing steps and that does not cause plastic deformation of a resin molded product as an object to be processed. [Structure] A processing apparatus for performing a cleaning process or the like on an object to be processed 4 placed in a processing tank 5 with a processing liquid composed of a supercritical fluid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing apparatus and a processing method for cleaning electronic devices such as relays and switches, precision devices and their components with a supercritical fluid.

[0002]

2. Description of the Related Art Conventionally, in the manufacturing process of electronic equipment such as relays and switches, precision equipment, etc., in order to remove oil and dust adhering to component parts, for example, in a cleaning tank. A semi-finished product to be processed such as a relay was dipped in the liquefied Freon (trade name) and cleaned with ultrasonic waves.

However, in this cleaning method, since the temperature of the liquefied freon is extremely low, the temperature of the object to be treated immediately after being taken out from the cleaning tank is also extremely low. For this reason, water in the air adheres to the surface of the object to be processed, causing water droplets.
Since the object to be treated must be dried with a dryer, there are many manufacturing steps and the productivity is low.

In an electronic device such as a relay, the organic gas generated from the resin-molded parts may corrode the contacts to cause a contact failure. The parts were vacuum heated to remove the organic gas.

However, in the above-mentioned degassing step, there is a problem that thermal stress generated during vacuum heating causes plastic deformation of the component parts, resulting in variation in dimensional accuracy and change in operating characteristics.

In view of the above problems, it is an object of the present invention to provide a processing apparatus and a processing method using a supercritical fluid which has a small number of processing steps and which does not cause deformation of a resin molded product which is an object to be processed.

[0007]

In order to achieve the above-mentioned object, a processing apparatus using a supercritical fluid according to the present invention is a processing apparatus for cleaning an object to be processed placed in a processing tank with a processing liquid. The treatment liquid is a supercritical fluid. The supercritical fluid may be liquefied carbon dioxide. Further, the method for treating with a supercritical fluid according to the present invention is a method for cleaning stains on an object to be treated placed in a treatment tank with a supercritical fluid. further,
The treatment method with the supercritical fluid according to the present invention is a method of degassing the organic gas generated from the inside of the object to be treated made of the synthetic resin material placed in the treatment tank by eluting it into the supercritical fluid. Good.

[0008]

Therefore, according to the processing apparatus and the processing method of the present invention, the object to be processed is washed with the supercritical fluid. In particular, if the object to be processed is made of a synthetic resin material, the organic gas generated from the inside will be eluted into the supercritical fluid and removed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings of FIGS. As shown in FIG. 1, the processing apparatus using a supercritical fluid according to the present embodiment includes a gas supply unit 1 that supplies a gas that becomes a supercritical fluid, a high-pressure pump that compresses the supplied gas and liquefies it, and the like. The gas compressing section 2, the temperature adjusting section 3 that heats the compressed and liquefied gas and adjusts it to a predetermined temperature to generate a supercritical fluid, and the stored object 4 to be contacted with the supercritical fluid to contaminate It comprises a processing tank 5 for removing substances and the like, a trap section 6 for removing contaminants and the like removed from the object to be treated 4 from the supercritical fluid, and a pressure adjusting section 7 for returning the supercritical fluid to a normal gas. . It should be noted that on-off valves 8 and 9 are provided on the upstream side and the downstream side of the processing tank 5, and the processing tank 5 is provided with temperature adjusting means 10 for maintaining a supercritical fluid state.

Therefore, the gas supplied from the gas supply unit 1 is compressed and liquefied by the gas compression unit 2, and the temperature adjustment unit 3
Is heated to a predetermined temperature and becomes a supercritical fluid. Then,
The supercritical fluid 3 flows from the upstream side to the downstream side of the treatment tank 5, contacts the object 4 to be treated arranged in the treatment tank 5, and removes contaminants adhering to the surface thereof and organic gas generated from the inside thereof. It is removed from the object to be processed 4. Then, the supercritical fluid flows into the trap section 6 to separate and remove the contaminants and the like, and after being vaporized by the pressure regulator 7, is sent to the gas compressing section 2 again, and is the same as the above. Circulate.

Examples of the gas used as the supercritical fluid used in this embodiment include carbon dioxide (CO ₂ ),
Examples of the inert gas include nitrogen, neon, and argon, but are not particularly limited.

The supercritical fluid produced from these gases means a fluid in a temperature and pressure range above the critical point,
For example, in the case of carbon dioxide, it means a fluid in the supercritical fluid region shown by hatching in FIG.

Since the density of this supercritical fluid is generally much closer to that of liquid than that of gas, its solubility in substances is similar to that of liquid. Moreover, the diffusion coefficient is much larger than that of liquids,
Since the moving speed and equilibrium speed of substances are high, the cleaning ability and degassing ability are high. In particular, in the present embodiment, when degassing is performed with a constant flow rate of supercritical fluid, the longer the processing time is, the less organic gas is generated from the synthetic resin material (FIG. 3), so that the degassing effect is large. There is. Further, the supercritical fluid has a characteristic that it is easily vaporized even at normal pressure. In addition, since the supercritical fluid consisting of carbon dioxide is harmless even when vaporized and can be used for cleaning treatment at around room temperature (about 30 to 50 ° C.), the object to be treated taken out from the supercritical fluid is in air. Even if left to stand, moisture in the air does not adhere to the surface of the object to be treated, and water drops do not occur.

According to this embodiment, the supercritical fluid is the processing tank 5
Since the new supercritical fluid constantly contacts the object 4 to be processed, it has the advantage of high cleaning and degassing efficiency.

The object to be processed according to the present embodiment is not limited to electronic equipment such as relays and switches, but may be other precision equipment. Further, the object to be processed is not limited to the assembled product or the semi-finished product, and may be, for example, a component alone or a synthetic resin material before molding. Further, it is not always necessary to apply the cleaning treatment and the degassing treatment at the same time, and may be applied when only the cleaning treatment or the degassing treatment is performed.

[0016]

As is apparent from the above description, according to the supercritical fluid processing apparatus of the present invention, the supercritical fluid, which is the processing liquid, is easily vaporized under normal pressure, so that the supercritical fluid from the inside of the processing tank is covered. When the processed product is taken out, the supercritical fluid vaporizes and disappears. Moreover, since the supercritical fluid is used for cleaning treatment or the like at around room temperature, water droplets do not occur on the surface of the object to be treated as in the conventional example. Therefore, the drying process as in the conventional example is unnecessary, the number of manufacturing processes is reduced, and the productivity is improved. In particular, if the supercritical fluid is composed of liquefied carbon dioxide, it is harmless to the human body even when vaporized. Moreover,
With the supercritical fluid, at the same time as cleaning, the organic gas generated from the inside of the object to be treated made of synthetic resin material is also extracted.
Since it can be removed, it is not necessary to separately provide a degassing step, the number of manufacturing steps is reduced, and the productivity is further improved. Further, since the supercritical fluid is generally used for cleaning treatment at around room temperature, even if the object to be treated is treated with the supercritical fluid, a large thermal stress does not occur in the object to be treated, and the object to be treated is plastic. No deformation occurs. Therefore, the dimensional accuracy does not vary,
The effect is that the operating characteristics do not change.

[Brief description of drawings]

FIG. 1 is a schematic view of a processing apparatus using a supercritical fluid according to the present invention.

FIG. 2 is a state diagram of carbon dioxide as a supercritical fluid according to the present invention.

FIG. 3 is a graph showing the degassing effect of the supercritical fluid according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Gas supply part, 2 ... Gas compression part, 3 ... Temperature adjustment part, 4
... processing object, 5 ... processing tank.

Claims (4)

[Claims] 1. A processing apparatus for cleaning an object to be processed placed in a processing tank with a processing liquid, wherein the processing liquid is a supercritical fluid. 2. The processing apparatus according to claim 1, wherein the supercritical fluid is liquefied carbon dioxide. 3. A method of treating with a supercritical fluid, which comprises cleaning a stain on an object to be treated placed in a treatment tank with a supercritical fluid. 4. A treatment method using a supercritical fluid, wherein an organic gas generated from the inside of an object to be treated made of a synthetic resin material placed in a treatment tank is eluted into a supercritical fluid to perform degassing treatment.