Cleaning method and cleaning apparatus for conveying and heating equipment

Abstract

It allows for easy installation and effectively removes deposits from the feed screw shaft of the conveying and heating device. [Solution] A cleaning method for a conveying and heating device, which has a female thread portion that engages with the screw shaft in a range of less than a semicircle of the cross-section of the screw shaft, and which cleans off deposits on the screw shaft by the female thread portion when the screw shaft rotates, wherein the crests of the screw grooves of the female thread portion are in contact with the valleys of the screw grooves of the screw shaft, and a gap exists between the crests of the screw shaft and the valleys of the screw grooves of the female thread portion.

Description

Technical Field

[0001] The present invention relates to a method and apparatus for cleaning a screw shaft of a conveyance heating apparatus, such as a reflow apparatus.

Background Art

[0002] A reflow apparatus includes a reflow furnace to which a printed circuit board having surface-mounted components mounted on both sides thereof, such as a work as a heated object, for example, a printed circuit board, is supplied by a conveyance chain. The reflow furnace has a configuration in which a plurality of heating zones having heating furnaces and one or a plurality of cooling zones are sequentially arranged along a conveyance path from an inlet to an outlet.

[0003] Each of the heating zones has an upper furnace body and a lower furnace body. For example, hot air is blown onto the printed circuit board from the upper furnace body of the zone, and hot air is blown onto the printed circuit board from the lower furnace body, thereby melting the solder in the solder composition and soldering the electrodes of the printed circuit board and the electronic components.

[0004] The solder composition (solder paste) contains powder solder and flux. The flux contains rosin and the like as components, removes the oxide film on the metal surface to be soldered, prevents reoxidation by heating during soldering, and functions as a coating agent that reduces the surface tension of the solder and improves wetting.

[0005] When heating a printed circuit board in a reflow apparatus, the flux in the solder composition on the printed circuit board vaporizes and fills the inside of the reflow furnace. The vaporized flux is likely to adhere to a portion with a low temperature. In the reflow apparatus, heating is performed while conveying the printed circuit board by a conveyance conveyor. The conveyance conveyor is configured to be able to adjust its width according to the size of the printed circuit board. Usually, the width adjustment of the conveyance conveyor is adjusted by moving one side of the conveyance conveyor by a width adjustment shaft (screw shaft) arranged in a direction orthogonal to the conveyance direction of the conveyance conveyor.

[0006] These width adjustment shafts are installed in multiple locations throughout the conveyor belt, and flux tends to adhere to them as the flux fumes cool. The gradual accumulation of flux can cause the width adjustment shafts to seize up. Furthermore, these width adjustment shafts are located in very narrow areas between furnace bodies in the substrate transport path, making maintenance work to remove flux difficult.

[0007] Furthermore, to prevent warping of printed circuit boards when they are transported in the furnace, a warp-preventing body is sometimes provided to support the printed circuit board from below, approximately at its center. In relation to the width adjustment of the transport conveyor mentioned above, the position of the warp-preventing body is also adjusted in the width direction, so a position adjustment shaft for the warp-preventing body is provided to vary its position.

[0008] To address the problem of flux adhering to the width adjustment shaft, a configuration has been proposed in which a non-engaging portion (notch) is provided in the nut attached to the width adjustment shaft, so that the adhering material is scraped off by the end face of the notch as the nut rotates (see Patent Document 1). Patent Document 2 describes attaching a similar nut to the position adjustment shaft of the warp prevention body. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Patent No. 5928635 [Patent Document 2] Patent No. 5928649 [Overview of the project] [Problems that the invention aims to solve]

[0010] In the configurations described in Patent Documents 1 and 2, the nut is always attached during both normal operation and maintenance, so it is necessary to slightly loosen the engagement between the width adjustment shaft or position adjustment shaft and the nut in order to ensure smooth feeding. As a result, there is a problem in that the flux adhering to the lowest surface of the groove portion of the screw shaft is not sufficiently scraped off.

[0011] Therefore, the object of this invention is to provide a cleaning method and cleaning apparatus for a conveying and heating apparatus that can be attached to a width adjustment shaft or a position adjustment shaft and can reliably remove deposits such as flux components. [Means for solving the problem]

[0012] The present invention relates to a cleaning method for a conveying and heating device, which has a female thread portion that engages with the screw shaft in a range of less than a semicircle of the cross-section of the screw shaft, and which cleans deposits on the screw shaft by the female thread portion when the screw shaft rotates. This is a cleaning method for a conveying and heating device in which the crests of the screw grooves of the female screw portion are in contact with the valleys of the screw grooves of the screw shaft, and a gap exists between the crests of the screw shaft and the valleys of the screw grooves of the female screw portion. [Effects of the Invention]

[0013] According to at least one embodiment, deposits adhering to the screw shaft can be reliably removed. Furthermore, the smooth rotation of the screw shaft is not hindered by the installation of the cleaning device. It should be noted that the effects described herein are not necessarily limited, and any of the effects described in the present invention may be used. Moreover, the effects illustrated in the following description should not be interpreted as limiting the scope of the present invention. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a schematic diagram showing a conventional reflow apparatus to which the present invention can be applied. [Figure 2] Figure 2 is a graph showing an example of a temperature profile during reflow. [Figure 3]FIG. 3 is a perspective view showing a state in which a cleaning device according to an embodiment of the present invention is attached to a reflow device. [Figure 4] FIGS. 4A and 4B are a plan view and a front view of a cleaning device according to an embodiment of the present invention. [Figure 5] FIG. 5 is an enlarged perspective view of a part of an embodiment of the present invention. [Figure 6] FIG. 6 is a front view, a plan view, a bottom view, and a side view of a cleaning device according to an embodiment of the present invention. [Figure 7] FIGS. 7A and 7B are front views used to explain the movement range of the cleaning device. [Figure 8] FIGS. 8A and 8B are a cross-sectional view of a female screw portion of a scraping portion and an enlarged cross-sectional view of a screwed portion of a screw. [Figure 9] FIGS. 9A and 9B are partial plan views and partial front views for explaining the mounting procedure of the cleaning device. [Figure 10] FIGS. 10A and 10B are partial plan views and partial front views for explaining the mounting procedure of the cleaning device. [Figure 11] FIGS. 11A and 11B are partial plan views and partial front views for explaining the mounting procedure of the cleaning device. [Figure 12] FIGS. 12A and 12B are partial plan views and partial front views for explaining the mounting procedure of the cleaning device. [Figure 13] FIGS. 13A and 13B are partial plan views and partial front views for explaining the mounting procedure of the cleaning device. [Figure 14] FIG. 14 is a perspective view for explaining the mounting procedure. [Figure 15] FIG. 15 is a perspective view for explaining the mounting procedure. [Figure 16] FIG. 16 is a perspective view for explaining the mounting procedure. [Figure 17] FIGS. 17A, 17B, and 17C are a plan view, a front view, and a cross-sectional view taken along line A-A of an example of a scraping portion using a ball screw. [Figure 18]Figures 18A, 18B, and 18C are plan, front, and cross-sectional views of another example of a scraping section using a ball screw. [Figure 19] Figures 19A, 19B, and 19C are plan, front, and cross-sectional views of another example of a scraping section using a ball screw. [Modes for carrying out the invention]

[0015] The present invention will be described below in the following manner, following embodiments. <1. An example of a reflow oven> <2. One Embodiment> <3. Variant> The embodiment described below is a preferred example of the present invention and is subject to various technically preferred limitations. However, the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description.

[0016] <1. An example of a reflow oven> Figure 1 shows a schematic configuration of a conventional reflow apparatus to which the present invention can be applied. A printed circuit board, with surface-mount electronic components mounted on both sides of the printed wiring board, is placed on a conveyor belt and transported into the heating chamber of the reflow apparatus from the input 101. The conveyor belt transports the printed circuit board at a predetermined speed in the direction of the arrow (from left to right in Figure 1), and the printed circuit board is removed from the output 102. The transport direction of the conveyor belt is horizontal.

[0017] The heating device is configured such that multiple heating furnaces are arranged along a transport path from the inlet 101 to the outlet 102, and hot air (heated atmospheric gas) is blown onto the printed circuit board by the heating furnaces. Multiple heating furnaces (referred to as zones) are arranged in line. Eight zones Z1 to Z8 from the inlet side are heating zones, and zone Z9 on the outlet side is a cooling zone. A forced cooling unit 103 is provided in relation to the cooling zone Z9. Each of the heating zones Z1 to Z8 has an upper furnace body and a lower furnace body, each including a blower, heater, blowing panel, etc. A buffer zone is formed between the heating zones and the cooling zones. Note that this number of zones is just an example, and a configuration with a different number of zones is also possible.

[0018] The aforementioned zones Z1 to Z9 control the temperature of the printed circuit board according to the temperature profile during reflow. Figure 2 shows a schematic example of a temperature profile. The horizontal axis represents time, and the vertical axis represents the surface temperature of the printed circuit board on which the electronic components are mounted. The first section is the heating section R1 where the temperature rises due to heating, the next section is the preheating section R2 where the temperature remains almost constant, the next section is the main heating section R3, and the last section is the cooling section R4. The heating section R1 and the preheating section R2 are preheating sections.

[0019] The heating section R1 is the period during which the substrate is heated from room temperature to the preheating section R2 (e.g., 150°C to 170°C). The preheating section R2 is a period during which isothermal heating is performed to activate the flux, remove the oxide film on the surface of the electrodes and solder powder, and eliminate uneven heating of the printed circuit board. The main heating section R3 (e.g., peak temperature of 220°C to 240°C) is the period during which the solder melts and the bonding is completed. In the main heating section R3, it is necessary to raise the temperature to a level above the solder melting point. Even after passing through the preheating section R2, uneven temperature rise may exist, so heating to a level above the solder melting point is necessary in the main heating section R3. The final cooling section R4 is the period during which the printed circuit board is rapidly cooled and the solder composition is formed. In the case of lead-free solder, the temperature in the main heating section R3 will be higher (e.g., 240°C to 260°C).

[0020] In Figure 2, curve 201 shows an example of the temperature profile for lead-free solder. An example of the temperature profile for Sn-Pb eutectic solder is shown by curve 202. Since the melting point of lead-free solder is higher than that of eutectic solder, the set temperatures in the preheating section R2 and the main heating section R3 are set higher compared to those for eutectic solder.

[0021] In the reflow apparatus shown in Figure 1, the temperature control of the heating section R1 in Figure 2 is mainly handled by zones Z1, Z2, and Z3. The temperature control of the preheating section R2 is mainly handled by zones Z4 and Z5. The temperature control of the main heating section R3 is handled by zones Z6, Z7, and Z8. The temperature control of the cooling section R4 is handled by zone Z9. Gaps exist between the multiple furnace bodies (zones) described above.

[0022] The conveyor system consists of, for example, conveyors arranged parallel to the conveying direction, on which printed circuit boards are placed on board-holding pins and moved within the furnace. Depending on the width of the printed circuit board, the position of one conveyor can be moved in a direction perpendicular to the conveying direction, and the distance between the conveyors is varied according to the width of the printed circuit board. The width of the conveyors is adjusted by moving one of the conveyors using a width adjustment shaft, which acts as a feed screw and is arranged perpendicular to the conveying direction of the conveyors. These width adjustment shafts are provided at multiple locations, for example, two locations, within the gaps between furnace bodies in the heating zone or within the buffer zone.

[0023] Furthermore, to prevent warping of the printed circuit board when it is transported in the furnace, a warp-preventing body is provided that supports the printed circuit board from below at approximately its center. In relation to the width adjustment of the transport conveyor mentioned above, the position of the warp-preventing body is also adjusted in the width direction, so a position adjustment shaft for the warp-preventing body is provided to vary its position. The width adjustment shaft and the position adjustment shaft are located in the same place. In the gaps or buffer zones between furnace bodies within the heating zone, the width adjustment shaft and the position adjustment shaft are located at different positions in the height direction due to their narrow width. For example, the position adjustment shaft may be located on the upper side and the width adjustment shaft on the lower side.

[0024] If flux adheres to the width adjustment shaft and position adjustment shaft, the smoothness of the feed operation will be impaired. Maintenance work to remove the flux will be necessary. It is relatively easy to open the upper hood of the reflow machine and manually clean the upper shaft, but cleaning the lower shaft is troublesome. A cleaning device according to one embodiment of the present invention can be attached to the lower shaft, such as the width adjustment shaft, during maintenance to remove deposits such as flux. In the following description, an example of attaching the cleaning device to the lower width adjustment shaft will be described, but the cleaning device may be attached only to the position adjustment shaft, or to both shafts.

[0025] <2. One Embodiment> One embodiment of the present invention will be described below with reference to the drawings. Figure 3 is a perspective view showing a cleaning device according to one embodiment attached to a reflow machine, Figures 4A and 4B are a plan view and a front view, respectively, of the cleaning device according to one embodiment attached to a reflow machine, and Figure 5 is a partially enlarged perspective view.

[0026] Side plates 108 and 109 are provided on opposite sides of the transport path of the reflow machine. A width adjustment shaft 111, a guide shaft 112, a position adjustment shaft 113, and a guide shaft 114 are spanned between the side plates 108 and 109. The width adjustment shaft 111 and the position adjustment shaft 113 are screw shafts that constitute the feed mechanism, while the guide shafts 112 and 114 are metal rods without threads. The width adjustment shaft 111 and the position adjustment shaft 113 are, for example, trapezoidal screws.

[0027] The width adjustment shaft 111, guide shaft 112, position adjustment shaft 113, and guide shaft 114 are located in the gap 110 (see Figure 3) between the furnace bodies in the heating zone of the reflow apparatus. Metal partition plates are provided on both sides of this gap. Since the width of this gap 110 is narrow, about 100 mm, these shafts are arranged sequentially in the height direction at almost the same position. As an example, the position adjustment shaft 113, guide shaft 114, width adjustment shaft 111, and guide shaft 112 are located from top to bottom.

[0028] A conveyor belt, with a transport chain positioned within a guide section, is used to transport printed circuit boards. A guide section 115 is attached to one side panel 108, and one side of the transport chain 116 is housed within the guide section 115. This transport conveyor has a fixed position in the width direction. The other transport conveyor, whose position is variable in the width direction, consists of a transport chain 118 positioned within the guide section 117. Transport chains 116 and 118 are equipped with pins, and printed circuit boards are placed on the opposing pins.

[0029] The guide section 117 is attached to the movable panel 119. The movable panel 119 has a boss 120 with a female screw structure that engages with the width adjustment shaft 111, a slidable boss 121 through which the guide shaft 112 passes, and a slidable boss 122 through which the guide shaft 114 passes, and has a plate surface that rises in a direction perpendicular to the feed direction. The guide section 117 that guides the transport chain 118 is attached via a mounting member at the tip of the movable panel 119.

[0030] The warp prevention body 123 is a protrusion attached in large numbers to a warp prevention chain arranged on the guide section 124. The tips of the warp prevention body 123 support the underside of the printed circuit board during transport, preventing warping. The guide section 124 is attached to the movable panel 125.

[0031] The movable panel 125 has a female threaded boss 126 that engages with the position adjustment shaft 113, and a guide shaft 114 that passes through it. It is supported by a slidable boss 127 and has a plate surface that rises in a perpendicular direction. The guide portion 124 is attached to the movable panel 125 via a mounting member that the movable panel 125 has at its tip.

[0032] The position adjustment shaft 113, located on the upper side, is relatively easy to clean manually from above, whereas the width adjustment shaft 111, located on the lower side, is difficult to clean manually. Therefore, a cleaning device (two sets of cleaning devices 10 and 50) is attached to the width adjustment shaft 111. In one embodiment, a deposit scraping section (appropriately referred to as a scraping section) 128, which serves as the cleaning section, is attached to the guide section 124 by a fixing plate. However, the cleaning device for the position adjustment shaft 113 may be omitted. However, if the position adjustment shaft 113 is located on the lower side, it is necessary to attach a cleaning device to the position adjustment shaft 113.

[0033] Figure 6 shows a front view, top view, bottom view, and side view of a cleaning device according to one embodiment of the present invention. The cleaning device according to one embodiment is configured by combining two sets of cleaning devices 10 and 50.

[0034] As shown in Figures 3, 4A, 4B, and 5, the cleaning devices 10 and 50 are mounted on either side of a movable panel 119 that moves in the width direction by the rotation of a width adjustment shaft 111. That is, the cleaning device 10 is positioned between the movable panel 119 and the side plate 109, and the cleaning device 50 is positioned between the movable panel 119 and the side plate 108.

[0035] The cleaning device 10 will now be described. The scraping section 12 is located on a rectangular plate-shaped base 11. The scraping section 12 is a rectangular parallelepiped made of a non-conductive material, such as synthetic resin, and has a female threaded section 13 on its upper surface that engages with the screw shaft. The female threaded section 13 is designed to engage with the screw groove of the screw shaft (width adjustment shaft 111) to be cleaned, in a range of less than a semicircle of the cross-section. The female threaded section 13 has the same pitch as the boss 120.

[0036] For example, polyetheretherketone (PEEK) is used as the synthetic resin. The reason for using a non-conductive material is to avoid the generation of conductive debris (contamination). In one embodiment, since it is used during maintenance, i.e., in a relatively low-temperature environment, a scraping part 12 made of synthetic resin can be used. However, a scraping part made of metal may also be used.

[0037] The female thread portion 13 is pressed against the width adjustment shaft 111, which acts as the male thread, from below. The scraping portion 12 has a screw groove, such as a trapezoidal groove, similar to that of the width adjustment shaft 111, so that it engages with the width adjustment shaft 111. Furthermore, because it is pressed against the width adjustment shaft 111, the range in which the screw groove is formed is less than 180°, for example, a range of angles slightly narrower than 180°.

[0038] Shafts 14 and 15, both identical in shape, pass through the scraping section 12 and are screwed to the base 11. Shafts 14 and 15 function as handles during installation. Two screws (four in total) are inserted into the plate-like sections extending outward from both sides of the scraping section 12, and these screws are screwed to the base 11. Compression springs 16a, 16b and 17a, 17b, for example, are attached to each screw. Therefore, the scraping section 12 is able to move up and down on the base 11, and furthermore, the compression springs 16a, 16b and 17a, 17b apply a constant pressure to the width adjustment shaft 111, pressing it toward its radial center.

[0039] The height of the scraping section 12 can be adjusted by the height of the base 11. In this way, the scraping section 12 is subjected to a spring-driven force that causes it to contact the width adjustment shaft 111, so that the male and female threads are in close contact with each other. Not limited to coil springs, other types of springs such as leaf springs may be used as the compression spring. The scraping section 12 may also be positioned at a location other than the lower side of the width adjustment shaft 111, for example, on the side.

[0040] Shafts 14 and 15 extend through cylindrical collars 18 and 19. Collars 18 and 19 are provided for height adjustment of the cleaning device 10. A fixing plate 22 is attached to the upper side of collars 18 and 19 by hexagonal nuts 20 and 21 to connect the two shafts 14 and 15 and to attach the cleaning device 10 to the movable panel 119. Hexagonal nuts 20 and 21 can be turned by hand.

[0041] The edge of the fixing plate 22 is bent downwards at a right angle, and the bent portion abuts against the surface of the movable panel 119 (see Figure 5). The fixing plate 22 has a notch that connects to the edge, allowing shafts 14 and 15 to be inserted horizontally from the edge. In other words, during assembly, the fixing plate 22 is first attached to the movable panel 119, and then shafts 14 and 15 are attached to the fixing plate 22.

[0042] The other cleaning device 50 has the same configuration as the cleaning device 10 described above. Corresponding parts are indicated by reference numerals in the 50s and 60s. In the cleaning device 50, the scraping section 52 is positioned on a base 51 attached to shafts 54 and 55. The scraping section 52 has a female screw portion 53 that engages with the width adjustment shaft 111 from below. The scraping section 52 is subjected to a spring force that pushes the female screw portion 53 upward by compression springs 56a, 56b and compression springs 57a, 57b.

[0043] Collars 58 and 59 are attached to shafts 54 and 55, and a fixing plate 62 is attached to the upper part of collars 58 and 59 by hexagonal nuts 60 and 61. The fixing plate 62, like the fixing plate 22, has its edge bent downward at a right angle, and two stays 63a and 63b protrude parallel and horizontally from the bent portion. The tips of stays 63a and 63b abut against the surface of the movable panel 119 and are fixed to the movable panel 119.

[0044] As shown in Figures 3 and 4, the stay 63b of the cleaning device 50 is made slightly longer than the lengths of bosses 120, 121, and 122. The two cleaning devices 10 and cleaning device 50 are connected by a movable panel 119. The scraping sections 12 and 52 of each cleaning device engage with the width adjustment shaft 111 before and after boss 120. Also, the scraping section 128 engages with the position adjustment shaft 113 at a position close to boss 126.

[0045] The width adjustment shaft 111 and the position adjustment shaft 113 are rotated by a drive source such as a motor (not shown), moving the parts that mesh with these shafts in the width direction. When the width adjustment shaft 111 and the position adjustment shaft 113 rotate, the scraping parts 12 and 52 scrape off deposits such as flux attached to the width adjustment shaft 11, and the scraped deposits fall downward. These deposits are removed as appropriate with a cleaner or the like. Similarly, the scraping part 128 also removes deposits from the position adjustment shaft 113 by scraping them off.

[0046] When cleaning the width adjustment shaft 111 with the cleaning devices 10 and 50, as shown in Figures 7A and 7B, the movable panel 125 to which the guide portion 124 of the anti-warping chain is attached is moved to a position closest to one side plate 108. Then, the cleaning devices 10, 50 and the movable panel 119 are moved between a position closest to the movable panel 125 (Figure 7A) and a position closest to the side plate 109 (Figure 7B). Depending on the degree of soiling, the cleaning devices 10 and 50 are moved back and forth one or more times.

[0047] Figures 8A and 8B are cross-sectional views of the female thread portion 13 of the scraping portion 12 and an enlarged cross-sectional view of the thread engagement portion. As shown in Figure 8A, the female thread portion 13 of the scraping portion 12 engages with the width adjustment shaft 111, which acts as a male thread. The width adjustment shaft 111 and the female thread portion 13 are trapezoidal threads with a thread angle of 30 degrees.

[0048] As shown in an enlarged view in Figure 8B, the crest (referred to as thread) M1 of the thread groove of the female thread portion 13 contacts the valley (referred to as thread valley) V2 of the thread groove of the width adjustment shaft 111. In the case of a typical trapezoidal screw and nut, there was a gap of about 0.75 mm. In addition, there is a gap of, for example, 0.5 mm between the thread M2 of the width adjustment shaft 111 and the thread valley V1 of the female thread portion 13. In the case of a typical trapezoidal screw and nut, the gap was about 0.25 mm. Furthermore, a gap exists between the groove wall S11 of the female thread portion 13 and the groove wall S21 of the width adjustment shaft 111, and a gap exists between the groove wall S12 of the female thread portion 13 and the groove wall S22 of the width adjustment shaft 111. As an example, if we let Q be the distance between the groove walls S21 and S22 of the width adjustment shaft 111 and the boundary of the thread M2, and let q be the distance between the groove walls S11 and S12 of the female thread portion 13 and the boundary of the thread root V1, (1 / 2) Q<=q<=(4 / 5) Q This relationship is intended to allow for easy scraping of adhering material and smooth feeding. A small gap may exist between the thread M1 and the thread root V2 due to manufacturing dimensional errors, and the gaps between the thread M2 and the thread root V1, as well as the gaps between the groove walls S11, S12 and S21, S22, are to be larger than such dimensional errors.

[0049] Since the threads of the female thread portion 13 are in contact with the thread root V2, most of the flux and other deposits adhering to the thread root V2 of the width adjustment shaft 111 are scraped off. The gap between the thread M2 and the thread root V1, as well as the gaps between the groove walls S11, S12 and S21, S22, allow the scraping portion 12 to feed smoothly. The deposits adhering to the groove walls S21, S22 of the width adjustment shaft 111 are scraped off because the gap on one side is eliminated by the reciprocating movement of the scraping portion 12. In this way, the width adjustment shaft 111 is thoroughly cleaned. The width adjustment shaft 111 is similarly cleaned by the scraping portion 52 of the cleaning device 50. Since two cleaning devices 10 and 50 are provided, the cleaning effect can be enhanced and the cleaning range can be expanded.

[0050] The installation procedure for using a cleaning device according to one embodiment of the present invention for cleaning the width adjustment shaft 111 of a reflow machine will be described with reference to Figures 9 to 16. Figures 9A, 10A, 11A, 12A, and 13A are partial plan views illustrating the installation procedure of the cleaning device, and Figures 9B, 10B, 11B, 12B, and 13B are partial front views illustrating the installation procedure of the cleaning device. Figures 14, 15, and 16 are perspective views illustrating the installation procedure.

[0051] As shown in Figures 9A and 9B, one of the two shafts of each cleaning device, shaft 15 and shaft 55, is removed. Next, with the longitudinal directions of bases 11 and 51 parallel to the width adjustment axis 111, shafts 14 and 15 are held and the scraping section 12 and scraping section 52 are lowered from above to the position below the width adjustment axis 111. Fixing plates 22 and 62 are pre-attached to the movable panel 119.

[0052] Next, as shown in Figures 10A, 10B, and 14, rotate shafts 14 and 54 by hand by 90 degrees to slide scraping sections 12 and 52 directly below width adjustment shaft 111.

[0053] Next, as shown in Figures 11A, 11B, and 15, the other shaft 15 and shaft 55 are attached to the bases 11 and 51. Since threads are formed, the shafts 15 and 55 are attached by turning them by hand.

[0054] Next, as shown in Figures 12A and 12B, shafts 14, 15, and 54 and 55 are brought closer to the movable panel 119. Shafts 14 and 15 are fitted into the two notches of the fixed plate 22, and shafts 54 and 55 are fitted into the two notches of the fixed plate 62.

[0055] Next, as shown in Figures 13A and 13B, lift shafts 14 and 15 until the female thread portion of the scraping section 12 and the peaks and valleys of the width adjustment shaft 111 align, and fix them in place with hexagonal nuts 20 and 21. Similarly, lift shafts 54 and 55 until the peaks and valleys align, and fix them in place with hexagonal nuts 60 and 61.

[0056] By following the above procedure, the cleaning devices 10 and 50 can be attached to the width adjustment shaft 111, as shown in Figure 16. Installation can be done easily without the use of tools.

[0057] <3. Variant> Although one embodiment of the present invention has been described in detail above, it is not limited to the above-described embodiment, and various modifications are possible based on the technical concept of the present invention. In the above-described embodiment, the width adjustment shaft 111 and the position adjustment shaft 113 are examples of trapezoidal screws, but other types of screws, such as ball screws, may also be used. Figures 17A, 17B, and 17C are a plan view, a front view, and a cross-sectional view along line AA of an example of a scraping section 12 using ball screws. The ball portion is made slightly smaller for cleaning. This example is one in which there is no contact, and the parts are arranged concentrically.

[0058] Figures 18A, 18B, and 18C are plan view, front view, and cross-sectional view along line AA of another example of the scraping section 12 using a ball screw. The ball portion is made slightly smaller for cleaning. This example shows the ball positioned to make contact in the X direction (the direction perpendicular to the width adjustment axis 111).

[0059] Figures 19A, 19B, and 19C are plan view, front view, and cross-sectional view along line AA of another example of the scraping section 12 using a ball screw. The ball portion is made slightly smaller for cleaning. This example shows the ball portion being positioned to make contact in the Y direction (the extension direction of the width adjustment shaft 111). Even with a ball screw, it is pressed against the width adjustment shaft 111 (ball screw) by a compression spring.

[0060] Furthermore, the present invention can be applied to multi-lane reflow soldering equipment in which multiple transport paths are arranged in parallel. Moreover, it is not limited to reflow soldering equipment; it can also be applied to jet soldering equipment, mounting equipment for bonding surface-mount components onto printed circuit boards with thermosetting adhesives, and equipment for curing solder resist formed on patterned copper-clad laminates. In other words, the present invention can be applied to cleaning screw shafts that have been vaporized by heat treatment.

[0061] The configurations, methods, processes, shapes, materials, and numerical values ​​listed in the above embodiments are merely examples, and different configurations, methods, processes, shapes, materials, and numerical values ​​may be used as needed. Furthermore, the configurations, methods, processes, shapes, materials, and numerical values ​​of the above embodiments can be combined with each other, as long as they do not depart from the spirit of the present invention. [Explanation of Symbols]

[0062] 10, 50... Cleaning device, 11, 51... Base, 12, 52... Scraping section, 13, 53... Female thread section, 14, 15, 54, 55... Shaft, 20, 21, 60, 61... Hexagonal nut, 22, 62... Fixing plate, 111... Width adjustment shaft, 113... Position adjustment shaft, 116, 118... Conveyor chain, 119, 125... Movable panel, 123... Anti-warping body

Claims

1. A cleaning method for a conveying and heating device, comprising having a female thread portion that engages with the screw shaft in a cross-sectional area of ​​less than a semicircle of the screw shaft, and cleaning off deposits on the screw shaft by the female thread portion when the screw shaft rotates, A method for cleaning a conveying and heating device, wherein the crests of the screw grooves of the female screw portion are in contact with the valleys of the screw grooves of the screw shaft, and a gap exists between the crests of the screw shaft and the valleys of the screw grooves of the female screw portion.

2. A method for cleaning a conveying and heating device according to claim 1, wherein a gap is provided between the groove wall of the screw shaft and the groove wall of the female screw portion.

3. The cleaning method for a conveying and heating apparatus according to claim 1 or 2, wherein the female screw portion is formed of a non-conductive material.

4. A method for cleaning a conveying and heating device according to claim 1 or 2, wherein the female screw portion engages with the screw shaft while a constant pressure is applied toward the radial center of the screw shaft.

5. A method for cleaning a conveying and heating apparatus according to claim 1 or 2, wherein two shafts are detachably attached to the female screw portion.

6. A method for cleaning a conveying and heating device according to claim 5, wherein one side of the shaft is removed, the female threaded portion is pressed against the screw shaft, and the other side of the shaft is attached.

7. A cleaning device having a female thread portion that engages with the screw shaft in a range of less than a semicircle of the cross-section of the screw shaft of a conveying and heating device, and which cleans deposits on the screw shaft by the female thread portion when the screw shaft rotates, A cleaning device for a conveying and heating device, wherein the crests of the screw grooves of the female screw portion are in contact with the valleys of the screw grooves of the screw shaft, and a gap exists between the crests of the screw shaft and the valleys of the screw grooves of the female screw portion.

8. A cleaning device for a conveying and heating device according to claim 7, wherein a gap is provided between the groove wall of the screw shaft and the groove wall of the female screw portion.

9. The cleaning device for a conveying and heating device according to claim 7 or 8, wherein the female screw portion is formed of a non-conductive material.

10. The cleaning device for a conveying and heating device according to claim 7 or 8, wherein the female screw portion engages with the screw shaft while a constant pressure is applied toward the radial center of the screw shaft.

11. A cleaning device for a conveying and heating device according to claim 7 or 8, wherein two shafts are detachably attached to the female screw portion, and the shafts and a movable panel that is moved when the screw shaft rotates are connected by a fixing plate.

12. A cleaning device for a conveying and heating apparatus according to claim 11, wherein two sets of cleaning devices according to claim 7 or 8 are provided on either side of the movable panel.

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