The present application is based on and claims priority from Japanese Patent Application No. 2011-235272, filed on Oct. 26, 2011 and No. 2012-142248, filed on Jun. 25, 2012, the disclosure of which is hereby incorporated by reference in its entirety.
1. Field of the Invention
The present invention relates to a dry washing device to wash an object by dispersing a cleanser to collide with the object, an object holder used in the dry washing device, and an anti-cleanser dispersing element set in the object holder.
2. Description of the Related Art
To manufacture print circuit boards, in soldering process with a flow soldering tank, a masking jig is often used for masking an area of a board other than that to be soldered. Such a masking jig is a plate with openings called dip palette or flow palette. It is necessary to periodically wash the surfaces of the jig to remove fluxes accumulated thereon in a repeated use, which decrease masking accuracy.
To remove fluxes or adhesives from an object such as jig, the top and bottom surfaces of the object is washed with an injected solvent in a tank, rinsed with water to remove the solvent, and dried with warm air. However, washing the object with a solvent by a washing machine not only uses a large amount of solvent but also consumes a large amount of energy for the disposal of liquid waste containing the fluxes and the drying process. This increases manufacturing costs and brings a large load on the environment.
To deal with the problem, a dry washing machine is available which blasts off a solid, light-weight, dispersive cleanser in a washing tank at a high speed, allows the cleanser to continuously contact or collide with an object, and separates attached matters on the object without using a solvent. This dry washing machine can effectively clean the object with a small amount of solvent by circulating the cleanser in the washing tank to repeatedly collide with the object. Especially, by use of a cleanser of a thin flexible plate-like shape, it can exert cleaning performance with a less amount of cleanser as much as that of ultrasonic cleaning.
For example, Japanese Patent No. 4531841 discloses a washing device having a downsized washing tank which can efficiently wash an object with uneven surfaces with a dispersed cleanser by placing the object outside the washing tank and sliding it relative to the opening of the tank. This device can prevent the cleanser from leaking to outside the tank and properly return it to the tank area so that it can maintain the number of cleanser particles to collide with the object and exert good, stable cleaning performance.
Specifically, referring to
An acceleration nozzle 11 is provided on the center of the bottom of the washing tank 6 to inject air streams to disperse the cleanser 5 and remove the fluxes from the object 4. The cleanser is absorbed into a suction duct 18 connected with a not-shown suction unit, returned to the washing tank 6 and used again. Further, the cleanser 5 which has lost motion energy and has been accumulated in the pool portion 19 is returned to the washing tank by a scraper 26 provided on the bottom surface of the object holder 3.
The object holder 3 is a plate longer than the object 4 and includes at the center a concave portion 23 in a form in conformity with the shape of the object 4. The concave portion 23 is made from an elastic material such as polyurethane rubber or foamed resin and the object 4 is pressed into the concave portion 23 and held by friction. The object holder is configured to tightly hold the object with no gap to prevent the cleanser from clogging and not to leak the air streams. This aims to prevent the cleanser accelerated by compressed air from scattering from the openings of the flow palette and maintain the cleaning performance of the washing tank.
Referring to
However, the object holder of the above machine faces problems as follows:
1. Since the concave portion of the holder is formed in accordance with the shape of a specific object, it cannot hold objects of different shapes and is lack of general versatility. Different holders need to be prepared for different objects.
2. It is troublesome to reverse the object to face the washing tank after setting it in the holder. Also, it will be difficult to reverse a large object, which requires labor.
3. Holding the object by friction is not stable, and the object may be suctioned by negative pressure in the tank and come off from the holder.
For the above reasons, a frame type object holder including a cover for closing only the opening of a washing tank and pins to partially hold an object is mostly in practical use. An object is placed from above in the frame of this holder fixed in a washing machine and supported by the pins on the bottom surface of the frame. The size of the frame is designed to match with the outer shape of an object. To hold a different object of a different outer shape, one side of the frame is slid for size adjustment. For a flow palette as a cleaning object, an operator first sets a printed circuit board or a plate of the same size as that of the printed circuit board on the surface of the flow palette opposite to the one to wash, to cover the openings of the flow palette. Then, the operator places the flow palette and the plate in the frame, and fixes them with the pins. The openings of the flow palette are closed with the plate and the side faces thereof are tightly attached to the inner surfaces of the object holder with no gap from which the cleanser can be scattered. Thus, the plate functions as an anti-cleanser dispersing element.
However, this kind of holder faces the following problems:
An object of the present invention is to provide an anti-cleanser dispersing element which can be easily set and prevent a cleanser from dispersing irrespective of different surface shapes of objects to wash and makes it easier to hold the object relative to a washing device.
According to one embodiment, provided is an anti-cleanser dispersing element for use in a dry washing device which disperses cleanser by an air stream to allow the cleanser to collide with an object for washing. The anti-cleanser dispersing element is disposed on a side of a holder of the object opposite to a side with which the cleanser collides. The anti-cleanser dispersing element is configured to be deformed by its own weight or pressure in accordance with an outer shape of the object, to tightly attach to the object with no gap and prevent the cleanser from moving to the opposite side of the holder.
Features, embodiments, and advantages of the present invention will become apparent from the following detailed description with reference to the accompanying drawings:
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
First Embodiment
A first embodiment is described with reference to
The separator 10 is connected to the suction duct 18 via the void 8 and the duct 18 is connected to a not-shown a suction unit which is configured to suction the sufficient amount of air from the tank relative to the amount of air blown from an accelerator nozzle 11 via the duct and separator and keep the tank under a negative pressure. The cleanser accelerator 7 includes an accelerator nozzle 11 with outlets and a not-shown compressed air supply unit as a compressor. The accelerator nozzle 11 is disposed so that the outlets are aligned in a straight line along the center of the tank bottom. The accelerator nozzle 11 is connected via an air pipe with a control valve to the compressed air supply unit which supplies compressed air to the nozzle to blast off the cleanser 5.
The pool 19 is in a concave shape, has a certain length and is provided at both sides of the tank. It has, at the corner of a level surface, a linear guide 20 as a rectangular column made from a smooth material such as fluorine resin with a thickness of about 5 mm, for example. The linear guide 20 works to hold the object holder 12 and guide it to move horizontally in the drawing together with a side guide 21. The holder 12 is connected with a not-shown driver such as DC motor, air cylinder, or wire driver and moved by the driver according to a control signal from a not-shown controller along the pool in parallel to the operation of the washing tank unit. The size of the pool is equal to or larger than the moving range of the object held by the holder.
The object holder 12 comprises a frame 14 to hold the object, facing the opening 6a and a pressure element 24 to apply pressure to an anti-cleanser dispersing element 22A held in the frame 14. The contour of the frame 14 is larger than the size of the opening 6a and includes a base 28 as a rectangular frame to cover the upper part of the opening 6a and walls 30 standing on the four sides of the base 28. The walls 30 are rectangular frames formed by plate folding processing and include top ends folded outward to easily insert the anti-cleanser dispersing element 22A in the frame 14. Pins 32 are provided on the opposite sides of the base 28 to protrude inward and support the object 4. An anti-leakage element 34 is provided on the bottom face of the base 28 to return the cleanser accumulated in the pool 19 to the tank 6. The anti-leakage element 34 is made of a brush with dense hairs to allow airflow but prevent the leakage of the cleanser 5.
The pressure elements 24 are toggle clamps each including a support element 36 fixed to the base 28, an arc arm 38 rotatably supported by the support element 36, and an adjusting pad 40 attached to the tip end of the arm 38 via a screw shaft. The arms 38 are rotated to press the anti-cleanser dispersing element 22A and the pressed elements 24 are locked by a not-shown lever. The pressure elements 24 are disposed at four positions, facing each other (
In
The core element 42 is inherently soft and not easily used. However, integrated with the rigid plate 44, its usability is improved. The plate 44 is also an interface to apply pressure evenly to the entire core element 42 at a small number of pressure points (four in the present embodiment).
Next, the washing operation of the dry washing device 1 according to the present embodiment is described referring to
The anti-cleanser dispersing element 22A is inserted in the frame 14 and pressed and locked by the pressure elements 24. The core element 42 is deformed by the pressure in accordance with the outer shape of the flow palette 4 as shown in
As shown in
When the anti-cleanser dispersing element 22A is locked with pressure, a closed space in which the cleanser is dispersed is formed between the flow palette 4 and tank 6. Then, the air is suctioned from the space by the suction unit driven by a not-shown controller. The controller drives the compressed air supply unit to supply compressed air to the accelerator nozzle 11 and generate a vertically upward air stream. By the air stream, the cleanser 5 is blasted off to collide with the flow palette 4 and efficiently remove attached flux from the surface of the flow palette 4. After the collision, the cleanser 5 drops by the air stream and gravity, and slides down near the accelerator nozzle 11 while suctioned over the separator 10. Thereby, attached powder fluxes on the flow palette are suctioned, separated by the separator 10 and collected by the suction unit through the duct 18. Further, the cleanser having dropped near the accelerator nozzle 11 is blasted off vertically upward again by the air stream from the accelerator nozzle 11. The dry washing device 1 repeats this operation to remove attached fluxes on the surface of the flow palette.
While the flow palette 4 is being cleaned with the cleanser 5, a part of the cleanser enters the gap between the pool 19 and the object holder 19. However, the anti-leakage element 34 under the object holder 12 can block the cleanser from leaking to the outside of the washing device 1, allowing the cleanser to be accumulated on the pool 19. The cleanser on the pool 19 is scraped by the anti-leakage element 34 along with the reciprocating movement of the object holder 12, returned to the tank 6, and blasted off vertically upward again by the air stream from the accelerator nozzle 11.
Thus, the anti-cleanser dispersing element 22A eliminates the gap in which the cleanser 5 is scattered upward so that the cleanser 5 can be recirculated in the tank 6 and over the pool 19 without reduction in amount. Because of this, the washing device does not decrease in cleaning performance due to a lack of the cleanser even in operation over a long time. Accordingly, it is made possible to certainly clean even large-size flow palettes by reciprocatively moving the object holder 12 relative to the tank 6.
The anti-cleanser dispersing element 22A can be made of the core element 42 alone without the surface layer 46. However, it was found by experiment that the low repulsive urethane sponge as the core element 42 is easily damaged by the collision with the cleanser 5. A large damage impairs the deformability of the core element. In the present embodiment the two different elements work for deformability and anti-wear separately, aiming for preventing early degradation of the anti-cleanser dispersing element 22A. The surface of the urethane sponge can be formed with coating having anti-wear property and no hindrance to the deformability of the urethane sponge.
The anti-wear property of the surface layer 46 of a stretch material does not continue for good and will be degraded over repeated use. A replaceable surface layer 46 is more cost-effective than the replacement of the entire element 22A.
Further, according to the present embodiment the top end of the surface layer 46 is fixed to the plate 44. It can be formed to be detachable with a loop fastener for replacement. Alternatively, it can be formed in a bag to wrap around the core element 42 and plate 44 and attached/detached by closing/opening the fastener. The present embodiment describes the use of low repulsive urethane sponge as the core element 42 by way of example. However, it can be an arbitrary element such as fluid as air or water or powder or powdery matter as long as a necessary deformability is acquired.
The cleanser 5 possesses a pencil hardness (measured under JIS K-56005-4) equal to or larger than that of attached fluxes and a folding strength of 45 or less (measured under JIS P8115). It cracks and creates new edges when continuously given an impact to thereby maintain flux removing performance. In the present embodiment the cleanser 5 is a thin rectangular strip in size of 1 to 100 mm2 and thickness of 0.05 to 0.2 mm, however, they should not be limited thereto The size, thickness, and material of the cleanser can be arbitrarily determined depending on the object.
The thin-strip cleanser is very small in mass relative to air resistance so that it is easily accelerated and dispersed by an air stream flowing in a direction of a large project area. Also, air resistance is small in a direction of a small project area so that the cleanser floating in this direction can maintain fast motion over a long distance. This increases the energy of the cleanser and the force acting on the object, resulting in effectively removing attached matter on the surface of the object and enhancing the cleaning efficiency since repeated circulation of the cleanser increases the frequency at which it contacts the object.
Second Embodiment
The anti-cleanser dispersing element 22B does not need the pressure elements, which eliminates the necessity for the operator to operate (lock or unlock) the pressure elements. It may be troublesome to handle the element 22B containing the beads but elevating and lowering the element 22b can be automated with a crane mechanism provided in the washing device. Alternatively, to omit the pressure elements 24, the plate 44 can be omitted or decreased in size and a horizontal protrusion is provided around the inner surfaces of the walls 30 to narrow the size of the opening of the frame 14. Then, the anti-cleanser dispersing element as a low repulsive urethane sponge is manually pressed into the frame and deformed. The protrusion functions to stop the element from restoring the original shape and maintain the deformation thereof.
Third Embodiment
A third embodiment is described with reference to
For cleaning a smaller object 4 than the opening size (maximum support area) of the frame 14, the movable plate 58 is moved in parallel by the manipulation of the adjustment shaft 56 to narrow the support area in accordance with the size of the object 4, as shown in
Depending on the size of the object 4, a space is created in the lower part of the support area but it can be similarly closed by the deformed anti-cleanser dispersing element 22. Alternatively, a frame 140 can be configured of the base 28 also functioning as the walls 30 and the area adjuster 54 can include plural adjustment shafts 56 (three in the drawing) for stable adjustment, as shown in
Fourth Embodiment
A fourth embodiment is described referring to
An anti-cleanser dispersing unit 68 is the anti-cleanser dispersing element integrated with the frame. It is connected with one side of the base 28 via a hinge 66. A lock mechanism 70 is disposed on the opposite side of the base 28 to securely connect the base 28 and the anti-cleanser dispersing unit 68. Referring to
The anti-cleanser dispersing unit is moved in a closed space with a shutter 78 and an outer element for safety reason. The shutter 78 is made of three slidable plates 78a, 78b, 78c. With the shutter 78 opened, the opened anti-cleanser dispersing unit 68 can be supported by the hinge 66 as a fulcrum as shown in
Next, the operation of the dry washing device 60 is described.
First, an operator opens the shutter 78 and releases the lock mechanism 70 of the anti-cleanser dispersing unit 68 to pull down the anti-cleanser dispersing unit 68. Then, the anti-cleanser dispersing unit 68 is held by the hinge 66 and the opened shutter 78. The anti-cleanser dispersing element 22A is placed with the stretch material covering the low repulsive urethane sponge on the top side. The operator places an object 4 in the anti-cleanser dispersing unit so that the surface to be washed comes on the top side. Then, by adjusting the length of the pins 72, the operator inserts one end of the object 4 below the pins 32, manually holds it down and pushes it into the anti-cleanser dispersing element 22A as shown in
Thus, the object 4 is held while pressed onto the anti-cleanser dispersing element 22A. The pins 32 are adjusted so that the object 4 comes below the outer frame of the anti-cleanser dispersing unit 68. Then, the entire unit 68 is rotated around the hinge as the fulcrum to connect with the base and be fixed with the lock mechanisms. When the device is operated with the shutter 78 closed as shown in
Fifth Embodiment
A fifth element is described with reference to
The use of a flow palette for the object is described.
The sponge roller 80 is rotated to press the surface of a flow palette to close the openings thereof. A loader and unloader 88 to carry palettes 4 are provided before and after the tank unit 84 and sponge roller 80. The palettes are always held by either of the loader and unloader and moved in parallel. The sponge roller 80 is supported by a rotational shaft 81 and rotated by the movement of the palette 4.
A space 92 is provided at downstream of the tank unit 84, in which the cleanser remaining on the sponge roller 80 and the palette 4 is blown off by an air nozzle 90 connected with the not-shown compressed air supply unit. The removed cleanser falls around an air inlet 94 of the tank unit 84 via a duct, and is suctioned into the air inlet 94 and blasted off again by the revolving air flows 96.
The suctioning air streams are supplied from an exit 100 of the space 92. At the exit 100 the air streams always flow towards the space 92. Because of this, the air streams from the nozzles 90 and the cleanser do not leak to outside the tank unit. Additionally provided with a short-curtain like element at the exit 100, it is possible to further prevent the leakage of the cleanser. Further, a scraper 102 can be provided to scrape off the cleanser attached to the surface of the sponge roller 80 due to static electricity and drop it in the space 92 and collect it in the tank unit. Thus, the dry washing device which can wash plate-like objects continuously is realized.
A dry washing device according to a sixth embodiment is described with reference to 14A to 14C. A dry washing device 110 or palette washing device comprises a washing unit 112 with an opening to blow off the cleanser by revolving air flows, have it collide with an object from the opening in a part of the revolving area and clean the object, an object holder 114 to hold the object in a washable position, and a three-axis type orthogonal robot 116 to move the washing unit 112 to different positions. The orthogonal robot 116 comprises an X shaft 118 for horizontal movement indicated by the arrow D1, a Y shaft 120 for orthogonal movement relative to the drawings, and a Z axis shaft 122 for vertical movement, a base to support these shafts, and a not-shown controller to control the movement of the shafts. The washing unit 112 is attached to the bottom end of the Z shaft 122 via a spring 123. The object holder 114 includes a support frame 124 for the anti-cleanser dispersing element 22, a pair of frames 126, 128 extending upward from the support frame 124, and the anti-cleanser dispersing element 22 accommodated in the frames 126, 128. The support frame 124 also works as the base of the orthogonal robot 116.
Pins 32 are fixed to the frame 128 to inhibit the palette from floating up by the repulsive force of the anti-cleanser dispersing element 22. Longer pins 32 are provided on the other frame 126 to be able to hold palettes of different sizes movably in the direction indicated by the arrow H (in
The washing unit 112 is connected with a suction hose 130 which is connected with a not-shown suction unit. The washing unit 112 is configured to generate revolving air flows at a high speed inside to circulate the cleanser, and allow the cleanser to collide with the object 4 and wash it in an opening 112a in the revolving area. When the opening 112a is closed with the object 4 while the washing unit 112 is being air-suctioned by the suction unit, outside air is flowed thereinto at a high speed from an inlet 112b, producing revolving air flows around a cylindrical element 112c at the center of the unit 112 as a rotational axis. Thereby, the cleanser is dispersed in the housing of the washing unit 112.
A not-shown porous element is provided between the connecting portion with the suction unit and the inside of the housing. The holes of this element are of a size enough to allow matters to be removed to pass therethrough but to prevent the cleanser from passing therethrough. When the inside of the housing is negatively pressurized by suction, the cleanser is absorbed onto the porous element until the revolving air flows are produced. Therefore, the cleanser is held inside the housing and does not leak to outside even with the opening 112a separated from the object 4. The washing unit 112 uses a housing disclosed in Japanese Patent Application Publication No. 2012-050973 filed by the applicant of the present invention. The washing unit 112 is enclosed in a rectangular case and a spring 123 is fixed to the case, thereby facilitating the connection of the Z shaft 122 and the unit 112 via the spring 123.
A seal element 132 with a smooth surface made from a flexible material is provided around the opening 112a of the washing unit 112. This helps the opening 112a closely attach to the palette 4 in accordance with the unevenness in the surface thereof. The seal element 132 can be a brush with nylon hairs or a sponge covered with a felt material.
The operation of the dry washing device 110 is described.
First, an operator provides a proper amount of cleanser in the housing of the washing unit 112 by suctioning it from the opening 112a or pouring it from the air inlet 112b. Next, the operator sets the palette 4 on the anti-cleanser dispersing element 22, and inserts one end of the palette 4 below the fixed pins 32 and pushes the other end to hold it down by manipulating the movable pins 32. Once the palette 4 is secured, the operator makes sure that all the openings of the palette are enclosed with the anti-cleanser dispersing element 22 and inputs an operation start signal to the not-shown controller to operate the suction unit. The controller then operates the X and Y shafts of the orthogonal robot 116 to move the washing unit 112 to the corner (washing home position) of the palette 4.
Then, the controller operates the Z axis of the orthogonal robot 116 to lower the washing unit 112 and press it down onto the palette until the spring 123 is deflected at a certain amount. By this pressure, the seal element 132 is deformed to closely attach to the palette and close the opening 112a of the washing unit 112, thereby decreasing the pressure in the washing unit 112 by suction and increasing the amount of air streams flowing thereinto from the air inlet 112b. Thus, the cleanser is dispersed by revolving air flows in the washing unit 112 and collides with the palette 4 closely attaching to the opening 112a. Thereby, the fluxes on the palette surfaces can be quickly removed.
Next, the controller moves in parallel the washing unit 112 contacting the palette 4 as indicated by the broken line in
It is preferable to move the washing unit in line with the shape of the palette if the palette is made of a frame only or a different-shape palette is used. By optimally moving the washing unit, the washing can be completed in a shorter time and the consumption of cleanser can be reduced.
In the present embodiment the orthogonal robot is used for the moving element for the washing unit. Alternatively, a horizontal or vertical multi-joint robot can be used.
Further, in the present embodiment the palette is disposed with the surface to be washed on the top side. However, the surface to be washed can face sideways or downward as long as the opening of the palette as an object can be closed with the anti-cleanser dispersing element. It can be washed by changing the movement of the washing unit.
Although the present invention has been described in terms of exemplary embodiments, it is not limited thereto. It should be appreciated that variations or modifications may be made in the embodiments described by persons skilled in the art without departing from the scope of the present invention as defined by the following claims.
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2011-235272 | Oct 2011 | JP | national |
2012-142248 | Jun 2012 | JP | national |
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Number | Date | Country | |
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