JP2016043337A - Cleaning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning method for removing both a metal foreign matter and oil excellently from a metal component, to which the metal foreign matter and oil have adhered.SOLUTION: A cleaning method comprises: a high-frequency ultrasonic cleaning step of performing the high-frequency ultrasonic cleaning of a substance 40 to be cleaned, by adding high frequency vibrations to washing water 13 in a washing tank 12; and then a low-frequency ultrasonic cleaning step of applying low-frequency vibrations to washing water 23 in a washing tank 22, thereby to perform the low-frequency ultrasonic cleaning of the substance 40 to be cleaned.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cleaning method, and more particularly to a cleaning method suitable for cleaning metal parts.

  The machined metal parts need to be cleaned because metal foreign matter such as cutting scraps at the time of machining or cutting oil used at the time of machining adheres to the machined metal parts. There is an ultrasonic cleaning method as a cleaning method for cleaning an object to be cleaned without being limited to metal parts. In addition, in ultrasonic cleaning, for example, a method of performing both cleaning that applies low-frequency vibration of 100 kHz or less to pure water and cleaning that applies high-frequency vibration of 1 MHz or more has been proposed (for example, patents). Reference 1).

JP-A-9-206713

  However, ultrasonic cleaning has advantages and disadvantages depending on the frequency of the ultrasonic wave, and at low frequencies, the foreign matter removal capability is high, but the processing uniformity is poor. The reverse is also true at high frequencies. And when removing the metal foreign matter adhering to the processed metal parts, when both the metal foreign matter and the oil are attached, simply performing ultrasonic cleaning will remove the metal foreign matter well. I can't.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a cleaning method that can satisfactorily remove both metallic foreign matter and oil from metallic parts to which metallic foreign matter and oil have adhered. There is.

  The cleaning method for solving the above problem is that after the high frequency ultrasonic cleaning step of applying high frequency ultrasonic cleaning to the cleaning water in the cleaning tank to perform high frequency ultrasonic cleaning of the object to be cleaned, low frequency vibration is applied to the cleaning water in the cleaning tank. In addition, a low-frequency ultrasonic cleaning process for performing low-frequency ultrasonic cleaning of an object to be cleaned is provided. Here, the high frequency vibration means vibration of 70 kHz or more, and the low frequency vibration means vibration of less than 70 kHz.

  For example, when cleaning an object to be cleaned, such as a machined metal part, to which metal foreign matter such as cutting scraps at the time of machining or cutting oil used at the time of machining adheres, the metal adheres to the metal. The frequency of the ultrasonic wave effective for removing oil is different from the frequency of the ultrasonic wave effective for removing metal foreign matter (metal powder) directly attached to the metal part. Therefore, even if ultrasonic cleaning is performed with ultrasonic waves having the same frequency, both oil and metal foreign matter cannot be removed satisfactorily. Further, even if ultrasonic cleaning is performed at a frequency effective for removal of metal foreign matter, the metal foreign matter cannot be satisfactorily removed when oil adheres to the metal foreign matter. However, in the present invention, since the low-frequency ultrasonic cleaning step is provided after the high-frequency ultrasonic cleaning step, after the oil adhering to the metal parts and the metal foreign matter is well removed in the high-frequency ultrasonic cleaning step, the low-frequency ultrasonic cleaning step is performed. The metal foreign matter is satisfactorily removed without being affected by oil in the high frequency ultrasonic cleaning process. Therefore, both the metal foreign matter and the oil can be satisfactorily removed from the metal part to which the metal foreign matter and the oil adhere.

  The high-frequency vibration is preferably 80 kHz to 1000 kHz. For example, oil can be removed even if the high-frequency vibration is 1 MHz or more, but the oil can be satisfactorily removed at a frequency of about 80 to 1000 kHz without increasing the frequency to the order of MHz.

It is preferable that the cleaning water in the high-frequency ultrasonic cleaning step is ozone water. The washing water may be water, but in the case of ozone water, the oil is decomposed by the action of ozone and the removability becomes high.
The low frequency vibration is preferably 50 kHz or less. According to this configuration, the metal foreign matter can be satisfactorily removed from the object to be cleaned after the oil is removed in the high frequency ultrasonic cleaning process.

  The washing water in the low frequency ultrasonic washing step is preferably alkaline water or ozone water. The cleaning water may be water, but an organic cleaning solution is also acceptable. In the case of alkaline water or ozone water, the surface of the metal foreign object is oxidized, and it is difficult to chemically cause the reattachment of the removed foreign object, and a rinse cleaning process is provided after the low frequency ultrasonic cleaning process This makes it easier for metal foreign objects to fall off the metal parts. In the case of alkaline water, the metal foreign matter and the surface of the object to be cleaned (metal part) are not caught by the etching effect, and the metal foreign matter can be removed.

  It is preferable that a rinsing cleaning step is provided after the low frequency ultrasonic cleaning step. According to this structure, a metal foreign material can be reliably removed from the metal component from which oil and the metal foreign material were removed by the high frequency ultrasonic cleaning process and the low frequency ultrasonic cleaning process. Moreover, when the rinse washing | cleaning process is provided after the low frequency ultrasonic cleaning process, the metal foreign material removed from the metal component by the low frequency ultrasonic cleaning process falls off from the metal part.

  According to the present invention, both metallic foreign matter and oil can be satisfactorily removed from the metallic part to which metallic foreign matter and oil adhere.

Schematic of a cleaning device.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIG.
As shown in FIG. 1, the cleaning device that performs the cleaning method includes a high-frequency ultrasonic cleaning device 11, a low-frequency ultrasonic cleaning device 21, and a rinse cleaning device 31.

The high-frequency ultrasonic cleaning device 11 performs a high-frequency ultrasonic cleaning process in which high-frequency vibration is applied to the cleaning water in the cleaning tank to perform high-frequency ultrasonic cleaning of an object to be cleaned.
The high-frequency ultrasonic cleaning device 11 includes a cleaning tank 12, and an ultrasonic oscillator (ultrasonic vibrator) 14 that applies high-frequency vibrations to the cleaning water 13 in the cleaning tank 12 is provided on the bottom surface of the cleaning tank 12. A recovery tank 15 is provided adjacent to the cleaning tank 12. The recovery tank 15 recovers the cleaning water 13 that has overflowed from the cleaning tank 12. A circulation pump 17 is connected to the recovery tank 15 via a pipe 16, and the cleaning water 13 in the recovery tank 15 returns to the cleaning tank 12 via the circulation pump 17. A filter 18 is connected to the inlet side of the circulation pump 17.

The low-frequency ultrasonic cleaning device 21 performs a low-frequency ultrasonic cleaning step of performing low-frequency ultrasonic cleaning of an object to be cleaned by applying low-frequency vibration to the cleaning water in the cleaning tank after the high-frequency ultrasonic cleaning step.
The low-frequency ultrasonic cleaning device 21 includes a cleaning tank 22, and an ultrasonic oscillator (ultrasonic vibrator) 24 that applies low-frequency vibration to the cleaning water 23 in the cleaning tank 22 is provided on the bottom surface of the cleaning tank 22. Yes. A recovery tank 25 is provided adjacent to the cleaning tank 22. The collection tank 25 collects the washing water 23 overflowed from the washing tank 22. A circulation pump 27 is connected to the recovery tank 25 via a pipe 26, and the cleaning water 23 in the recovery tank 25 returns to the cleaning tank 22 via the circulation pump 27. A filter 28 is connected to the inlet side of the circulation pump 27.

  The rinse cleaning device 31 performs a rinse cleaning process on the surface of the object to be cleaned after the low frequency ultrasonic cleaning process. In addition, the to-be-cleaned object wash | cleaned with the rinse washing | cleaning apparatus 31 is dried with a drying apparatus at the drying process which is not illustrated.

  The rinse cleaning device 31 includes a shower cleaning tank 32, and a shower nozzle 33 is provided on the inner surface of one side wall of the shower cleaning tank 32. The shower nozzle 33 sprays cleaning water 37 supplied from the cleaning water tank 36 through a pipe 35 by a pump 34 in a horizontal direction. A filter 38 is provided on the inlet side of the pump 34. The washing water 37 sprayed from the shower nozzle 33 is collected in the washing water tank 36.

  The transfer of the object to be cleaned 40 between the high-frequency ultrasonic cleaning device 11, the low-frequency ultrasonic cleaning device 21, the rinsing cleaning device 31, and the drying device (not shown) is for transfer with a bottomed box shape formed of a coarse wire mesh. The container 41 is suspended by a rope 42 and moved by a moving device (not shown).

Next, the operation of the cleaning apparatus configured as described above will be described.
Ozone water is used as the cleaning water 13 of the high-frequency ultrasonic cleaning device 11, and ozone water or alkaline water is used as the cleaning water 23 of the low-frequency ultrasonic cleaning device 21. As shown by the solid line in FIG. 1, the transfer container 41 in which aluminum parts are inserted as metal parts as the object to be cleaned 40 is first cleaned with the cleaning water 13 in the cleaning tank 12 of the high-frequency ultrasonic cleaning device 11. Sink inside. The ultrasonic oscillator 14 applies high-frequency vibration of 80 kHz to 1000 kHz (for example, 80 kHz or 200 kHz) to the cleaning water 13.

  Metal foreign matter or oil adheres to the object to be cleaned 40, but the oil adhering to the object to be cleaned 40 or metal foreign matter is removed by the high-frequency vibration applied by the ultrasonic oscillator 14. Since the oil does not adhere strongly to the object to be cleaned 40, it is not necessary to remove it strongly with low frequency vibration, and it can be removed with high frequency vibration. Moreover, in high frequency vibration, the removal force by ultrasonic vibration acts uniformly on the entire surface of the object to be cleaned 40, and oil is efficiently removed. When ozone water is used as the cleaning water 13, in addition to the removal effect by ultrasonic vibration, a part of the oil is decomposed by the action of ozone, so the oil removal function is enhanced. The oil removed from the object to be cleaned 40 and the metal foreign matter floats to the upper side of the cleaning water 13 and is recovered in the recovery tank 15 together with the overflowing cleaning water 13. The washing water 13 collected in the collection tank 15 is supplied to the washing tank 12 through the pipe 16 by the action of the circulation pump 17. When the cleaning water 13 moving from the recovery tank 15 toward the circulation pump 17 passes through the filter 18, the oil in the cleaning water 13 is removed by the filter 18, and the cleaning water 13 from which the oil has been removed is the cleaning tank 12. To be supplied.

  When a predetermined time set in advance elapses, the object to be cleaned 40 is lifted from the cleaning tank 12 of the high-frequency ultrasonic cleaning device 11 together with the transfer container 41, and the cleaning water in the cleaning tank 22 of the low-frequency ultrasonic cleaning device 21 is washed. 23. The set time is set by a test, for example.

  In the low frequency ultrasonic cleaning device 21, vibration is applied to the cleaning water 23 at a low frequency of 50 kHz or less (for example, 30 kHz). In high-frequency ultrasonic cleaning, oil is efficiently removed, but metal foreign matter is not removed because the adhesion between metals is greater than that of oil. Therefore, metal foreign matters are removed by performing low-frequency ultrasonic cleaning, which has a higher removing power than high-frequency ultrasonic cleaning. In the state where the oil covers the metal foreign object, it is difficult to remove the metal foreign object. However, since the low-frequency ultrasonic cleaning is performed after the oil is removed, the metal foreign object is well removed.

  When alkaline water or ozone water is used as the cleaning water 23, it is difficult to chemically cause the reattachment of the metal foreign matter that has fallen off due to the surface oxidation of the metal foreign matter, or the metal foreign matter is removed from the object to be cleaned 40 in the subsequent rinsing process. It can be easily removed. Further, in the case of alkaline water, when the metal of the object to be cleaned 40 is aluminum, the metal foreign matter and the surface of the object to be cleaned 40 can be eliminated and removed by the etching effect.

  The washing water 23 in the collection tank 25 is supplied to the washing tank 22 through the pipe 26 by the action of the circulation pump 27, and the washing water 23 overflowed from the washing tank 22 is collected in the collection tank 25. When the cleaning water 23 moving from the recovery tank 25 toward the circulation pump 27 passes through the filter 28, the oil in the cleaning water 23 is removed by the filter 28, and the cleaning water 23 from which the oil has been removed is the cleaning tank 22. To be supplied.

  Since the low-frequency ultrasonic cleaning device 21 is inefficient but oil can be removed, the oil remaining in the object to be cleaned 40 and the metal foreign matter without being removed by the high-frequency ultrasonic cleaning device 11 becomes low-frequency ultrasonic cleaning device. In 21, the object to be cleaned 40 and the metal foreign matter are removed. The removed oil floats to the upper side of the washing water 23 and is collected in the collection tank 25 together with the washing water 23 that overflows. The oil recovered in the recovery tank 25 is removed by the filter 28 when the cleaning water 23 moving from the recovery tank 25 toward the circulation pump 27 passes through the filter 28, and the cleaning water 23 from which the oil has been removed is cleaned. It is supplied to the tank 22.

  When a predetermined time set in advance elapses, the object to be cleaned 40 is pulled up together with the transfer container 41 from the cleaning tank 22 of the low-frequency ultrasonic cleaning device 21, and the rinse cleaning device 31 as shown by a chain line in FIG. It is arrange | positioned in the state suspended in the shower washing tank 32. Then, the object to be cleaned 40 is rinsed with the cleaning water 37 sprayed from the shower nozzle 33.

  For this reason, the object 40 to be cleaned after the low-frequency ultrasonic cleaning process is subjected to low-frequency ultrasonic cleaning as compared with a cleaning method in which the object 40 is immersed in a cleaning tank containing cleaning water and pulled up. The metal foreign matter peeled off from the cleaning object 40 can be efficiently dropped from the cleaning object 40. In the rinse cleaning, the metal foreign matter separated from the object to be cleaned 40 by ultrasonic cleaning in the low-frequency ultrasonic cleaning device 21 is dropped from the object to be cleaned 40. Further, the metallic foreign matter that has been peeled off from the object to be cleaned 40 by ultrasonic cleaning is peeled off from the object to be cleaned 40. Moreover, the alkaline water and ozone water adhering to the to-be-cleaned object 40 are washed away.

  After the shower cleaning is performed for a predetermined time, the object to be cleaned 40 is transferred together with the transfer container 41 to a drying device in a drying process (not shown) and dried by the drying device. As the drying device, for example, a hot air dryer or an air dryer is used.

  In the high-frequency ultrasonic cleaning process, pure water was used as the cleaning water 13, and the high-frequency ultrasonic cleaning of the object to be cleaned 40 was performed for 3 minutes by setting the high-frequency frequency by the ultrasonic oscillator 14 to 80 kHz. Next, in the low-frequency ultrasonic cleaning step, alkaline water was used as the cleaning water 23, and the low-frequency ultrasonic cleaning of the article 40 to be cleaned was performed for 3 minutes by setting the low-frequency frequency by the ultrasonic oscillator 24 to 40 kHz. Next, in the rinsing step, shower cleaning of the article to be cleaned 40 was performed using pure water as the cleaning water 37 for 5 minutes. After the shower cleaning, the object to be cleaned 40 was dried with a drying device. Both the foreign metal and the oil were satisfactorily removed from the object 40 to be cleaned.

According to this embodiment, the following effects can be obtained.
(1) The cleaning method is low for the cleaning water 23 in the cleaning tank 22 after the high-frequency ultrasonic cleaning step of applying high-frequency vibration to the cleaning water 13 in the cleaning tank 12 to perform high-frequency ultrasonic cleaning of the object 40 to be cleaned. A low-frequency ultrasonic cleaning process is performed in which low-frequency ultrasonic cleaning of the object to be cleaned 40 is performed by applying frequency vibration. For example, when cleaning the object to be cleaned 40, such as a machined metal part, to which metal foreign matter such as cutting scraps at the time of machining or cutting oil used at the time of machining adheres, the high frequency ultrasonic wave After the oil adhering to the metal part and the metal foreign matter is removed well in the cleaning process, the metal foreign matter is successfully removed in the low-frequency ultrasonic cleaning process without being affected by the oil or in a small state. Therefore, both the metal foreign matter and the oil can be satisfactorily removed from the metal part to which the metal foreign matter and the oil adhere.

  (2) The high frequency vibration is 80 kHz to 1000 kHz. For example, oil can be removed even when the frequency of the high frequency vibration is 1 MHz or more, but the oil can be well removed at a frequency of about 80 to 1000 kHz without increasing the frequency to the order of MHz. Less.

(3) The cleaning water 13 in the high-frequency ultrasonic cleaning process is ozone water. The washing water 13 may be water, but in the case of ozone water, the oil is decomposed by the action of ozone and the removability becomes high.
(4) The low frequency vibration is 50 kHz or less. According to this configuration, the metal foreign matter can be satisfactorily removed from the object to be cleaned 40 after the oil is removed in the high frequency ultrasonic cleaning process.

  (5) The cleaning water 23 in the low frequency ultrasonic cleaning process is alkaline water or ozone water. The cleaning water 23 may be water, but in the case of alkaline water or ozone water, the surface of the metal foreign matter is oxidized, and the reattachment of the dropped foreign matter can be made difficult to occur chemically. When the rinse cleaning process is provided after the sonic cleaning process, the metal foreign matter easily falls off the metal part. Further, in the case of alkaline water, the metal foreign matter and the surface of the object to be cleaned 40 (metal part) can be eliminated by the etching effect and can be removed.

  (6) A rinse cleaning step is provided after the low frequency ultrasonic cleaning step. According to this configuration, the metal foreign matter can be reliably removed from the object to be cleaned 40 (metal part) from which the oil and metal foreign matter have been removed by the high-frequency ultrasonic cleaning step and the low-frequency ultrasonic cleaning step. Moreover, when the rinse washing | cleaning process is provided after the low frequency ultrasonic cleaning process, the metal foreign material removed from the metal component by the low frequency ultrasonic cleaning process falls off from the metal part.

The embodiment is not limited to the above, and may be embodied as follows, for example.
The rinse cleaning device 31 used in the rinse cleaning step may have a configuration including a plurality of shower cleaning tanks 32, that is, a configuration that performs shower cleaning in multiple stages.

O The rinse washing | cleaning apparatus 31 may be the structure which injects the washing water 37 with the shower nozzle 33 from both sides with respect to the to-be-washed | cleaned material 40.
The shower nozzle 33 is not limited to the configuration in which the cleaning water 37 is ejected in the horizontal direction, and may be configured to eject the cleaning water 37 from the oblique direction or the vertical direction with respect to the object to be cleaned 40.

  O Washing water is not limited to a configuration in which it is circulated and used independently in a high-frequency ultrasonic cleaning process, a low-frequency ultrasonic cleaning process, and a rinse cleaning process. For example, the common cleaning water may be circulated in the order of the rinse cleaning step → the low frequency ultrasonic cleaning step → the high frequency ultrasonic cleaning step.

  O It is good to rock the transfer container 41 in the cleaning tank 12 and the cleaning tank 22. In this case, the unevenness of ultrasonic waves is alleviated. Moreover, a flow is generated by moving the transfer container 41, and foreign matters are likely to fall off.

In the high frequency ultrasonic cleaning apparatus 11, simple water may be used as the cleaning water 13 instead of ozone water.
In the low-frequency ultrasonic cleaning device 21, simple water may be used as the cleaning water 23 instead of alkaline water or ozone water, or acidic water may be used.

  O The rinse cleaning device 31 used in the rinse cleaning process may not be a device that performs shower cleaning. For example, it replaces with the shower washing tank 32, the immersion tank (washing tank) which can immerse the to-be-cleaned object 40 is provided, and the to-be-cleaned object 40 is immersed in the washing water in the immersion tank. The cleaning may be performed by swinging with respect to the cleaning water.

  The transfer container 41 may be a barrel type (barrel container). The barrel container is formed in a cylindrical shape by a metal mesh or a perforated plate, and is driven to rotate about an axis in the cleaning tank. By rotating the barrel container, when the object to be cleaned 40 is a bottomed part, the cleaning water is replaced, and the cleaning effect is enhanced. As a configuration for rotating the barrel container around its axis, for example, a rotation shaft protrudes from the side wall sealing both ends of the cylindrical portion, and the barrel container can be rotated to the barrel container support means via the rotation shaft. It is supported. The rotating shaft is rotated by the rotation driving means. The barrel container is provided with an inlet / outlet through which the article to be cleaned 40 is taken in / out of the barrel container, and the inlet / outlet is closed by an openable / closable or removable lid.

The ultrasonic oscillators 14 and 24 may be provided on the side walls instead of the bottom walls of the cleaning tanks 12 and 22.
The ultrasonic oscillators 14 and 24 are not limited to the outside of the cleaning tanks 12 and 22, and may be provided at positions where the ultrasonic oscillators 14 and 24 come into contact with the cleaning water 13 and 23 without passing through the walls of the cleaning tanks 12 and 22.

  In the high-frequency ultrasonic cleaning device 11, instead of supplying the cleaning water 13 in the recovery tank 15 to the cleaning tank 12 via the filter 18 by the circulation pump 17, the oil is separated from the cleaning water 13 in the recovery tank 15 by the oil / water separator. Then, the cleaning water 13 may be supplied to the cleaning tank 12 by the circulation pump 17 through the filter 18. In this case, the replacement period of the filter 18 becomes long.

The object to be cleaned 40 is not limited to an aluminum metal part, but may be another metal part.
The number of objects 40 to be cleaned at one time is not limited to one, and may be plural depending on the size of the object 40 to be cleaned and the sizes of the cleaning tanks 12 and 22.

The transfer of the object to be cleaned 40 between the steps is not limited to the method using the transfer container 41 suspended from the rope 42, and for example, a belt conveyor may be used.
If the object to be cleaned 40 is large, the robot arm may directly grip the object to be cleaned 40 and transfer it to the next process.

  O A drying step is not particularly provided, and the product may be naturally dried during storage until the object to be cleaned 40 after rinsing is used.

  12, 22 ... Cleaning tank, 13, 23, 37 ... Cleaning water, 40 ... Object to be cleaned.

Claims (6)

  After the high-frequency ultrasonic cleaning process, which applies high-frequency vibration to the cleaning water in the cleaning tank to perform high-frequency ultrasonic cleaning of the object to be cleaned, low-frequency vibration is applied to the cleaning water in the cleaning tank to reduce the frequency of the object to be cleaned. A cleaning method comprising a low-frequency ultrasonic cleaning step for performing ultrasonic cleaning.   The cleaning method according to claim 1, wherein the high-frequency vibration is 80 kHz to 1000 kHz.   The cleaning method according to claim 1 or 2, wherein the cleaning water in the high-frequency ultrasonic cleaning step is ozone water.   The said low frequency vibration is 50 kHz or less, The cleaning method as described in any one of Claims 1-3.   The cleaning method according to any one of claims 1 to 4, wherein the cleaning water in the low-frequency ultrasonic cleaning step is alkaline water or ozone water.   The cleaning method according to any one of claims 1 to 5, further comprising a rinse cleaning step after the low-frequency ultrasonic cleaning step.