JPH04134264U - air reflow device - Google Patents

Abstract

(57) [Summary] [Purpose] To improve productivity and workability by forcing cooling inside the heating furnace. [Configuration] Along the conveyor 31, the first preheat furnace 41,
A series of heating furnaces consisting of a second preheat furnace 42, a third preheat furnace 43, a first reflow furnace 44, and a second reflow furnace 45 are arranged. A nozzle 51 for blowing cold air into the furnace is provided at the bottom of each heating furnace. Cold air supply piping 52 is connected to each of these nozzles 51, respectively. A cold air volume adjustment valve 53 for adjusting the flow rate of cold air is provided in each of the pipes. By blowing cold air into the furnace from the nozzle 51,
For example, when conveying a substrate W using a low melting point solder by the conveyor 31, the temperature set in the furnace is lowered. After finishing work, quickly lower the temperature inside the furnace. Protects components such as electrolytic capacitors mounted on the bottom of the board from high heat.

Description

[Detailed explanation of the idea]

0001 [Purpose of invention]

0002

[Industrial application field]

This invention relates to an air reflow device used for reflow soldering. be.

0003

[Conventional technology]

A conventional air reflow device is disclosed in Japanese Patent Application Laid-Open No. 61-289697. A workpiece conveyor is installed in the heating furnace, and multiple pieces of work are conveyed along this conveyor. A number of preheat heaters and reflow ovens are provided, so that the conveyor The workpiece (component mounting board) being transported was preheated using a preheating heater. After that, radiant heat from the infrared rays irradiated from the heater in the reflow oven and Reflow soldering of component-mounted boards can also be performed using forced convection heat using hot air. is known.

0004

[Problem that the idea aims to solve]

In such an air reflow device, the type of substrate changes and the set temperature inside the furnace changes. When changing the temperature or increasing the temperature, use the preheat heater and reflow heater. By controlling the power applied to the heater, you can forcibly raise the temperature in a relatively short period of time. However, if you need to lower the set temperature, turn off the power to each heater. Even if the furnace temperature is stopped, it takes time for the temperature inside the furnace to drop to the changed temperature due to natural cooling. Productivity is not good.

[0005] In addition, with this type of reflow equipment, the temperature inside the furnace remains at around 100°C even after the work is finished. If you stop the equipment before the temperature drops below the specified temperature, it will affect the heater, etc. It is not possible to stop the conveyor, etc. until it reaches a certain point, resulting in poor work efficiency.

[0006] This invention was developed in consideration of these points, and enables forced cooling inside the furnace. The purpose is to improve productivity and workability.

[0007] [Structure of the idea]

[0008]

[Means to solve the problem]

The invention according to claim 1 is a forced heating method using hot air circulating through a heater in a heating furnace. An air system that uses flowing heat to reflow solder workpieces that are transported through a heating furnace. In the flow device, the heating furnace is provided with a cold air blowing section 51 that blows cold air into the furnace. This is an air reflow device.

[0009] The invention according to claim 2 is a forced heating method using hot air circulating through a heater in a heating furnace. An air system that uses flowing heat to reflow solder workpieces that are transported through a heating furnace. In the flow device, a plurality of conveyors 31 are arranged along the conveyor 31 that conveys the workpiece W. Heating furnaces 41 to 45 and a cooling system installed in each of these heating furnaces that blows cold air into the furnace. The wind blowing section 51 is connected to each of these cold air blowing sections 51, and a cold air volume adjustment bar is connected to the wind blowing section 51. Air lift equipped with cold air supply piping 52 provided in each pipe line. It is a raw device.

0010

[Effect]

The invention according to claim 1 is useful when lowering the set temperature in the furnace or when reducing the temperature in the furnace after finishing work. When lowering the heating temperature, blowing cold air into the heating furnace from the cold air blowing section 51 Forced cooling inside.

[0011] The invention according to claim 2 provides an arbitrary cold air volume adjustment valve for a plurality of heating furnaces 41 to 45. 53 is selectively adjusted to supply the required flow rate of cold air to the cold air blowing section 51 of the heating furnace. and forced cooling individually.

0012

【Example】 Hereinafter, the present invention will be described in detail with reference to the embodiments shown in FIGS. 1 to 3.

[0013] FIG. 2 shows the internal structure of the reflow soldering device, with external parts inside and outside the device body 11. A side furnace body 12 is provided, and an inner furnace body 13 is provided inside this outer furnace body 12. A heating unit 14 is arranged above the furnace body 13. Hinge 15 at the top of the device body 11 A lid body 16 is attached to the lid body 16 so as to be openable and closable, and the outer furnace body 12 can be separated from the lid body 16. The upper part 12a of the outer furnace body is integrally attached by a connecting member (not shown), and this upper part of the outer furnace body The heating unit 14 is integrally attached to 12a by a connecting member (not shown). Ru. Therefore, when the lid part 16 of the device main body 11 is opened, the heating unit 14 also opens the inner furnace body. 13, so maintenance of this heating unit 14 and infrared rays (described later) are possible. This is convenient when selecting irradiation manually.

[0014] The heating unit 14 has a plurality of sheathed heaters 22 installed between the left and right sides of the frame 21. radiant heat from infrared rays irradiated from each heater 22 and each heater 22. A heating device that uses forced convection heat from hot air to reflow solder workpieces. However, an infrared shielding plate 23 is pivotally supported under each heater 22 so as to be openable and closable. There is.

[0015] This infrared shielding plate 23 opens and closes by rotating, and is irradiated by the heater 22 in the closed state. It blocks only the infrared rays that are emitted. Furthermore, the heater 22 is fed into the upper part of the frame 21. A punching plate (perforated plate) 24 is installed for the purpose of making the air flow uniform.

[0016] A substrate conveyor 31 is arranged below the heating unit 14. This The conveyor 31 has a pair of left and right coils that pass through the furnace through an opening 32 for loading or unloading substrates. The conveyor frames are arranged in parallel, and the left and right conveyor frames are A long and thin endless chain is provided, and the workpiece to be soldered is placed between the left and right chains. The component-mounted substrate W as a rack is transported horizontally in a suspended state.

[0017] A temperature sensor such as a thermocouple that detects the temperature inside the furnace is installed below the substrate conveyor 31. 33 is inserted.

[0018] On the left and right sides of the inner furnace body 13, a pair of sirocco fans are provided on a common rotating shaft 34. 35 is provided. The rotating shaft 34 is driven by a motor 37 via a belt transmission mechanism 36. It is driven by By controlling the rotation speed of this motor 37, the sirocco fan 35 controls the amount of air circulated in the furnace.

[0019] The air sucked in from the center of the furnace by this sirocco fan 35 is then transferred to the outside. It is discharged between the side furnace body 12 and the inner furnace body 13, rises, and is discharged from the top of the heating unit 14. It passes through a pinching plate 24, is heated by a heater 22, and passes through an infrared shielding plate 23, which will be described later. The solder paste on the board W is reflowed by forced convection heat. Ru.

[0020] Figure 1 shows the overall arrangement structure of a reflow soldering device, and shows the component mounting base. Along the conveyor 31 that conveys the plate W, a first preheating furnace 41 and a second preheating furnace 41 are installed. Consisting of a furnace 42, a third preheat furnace 43, a first reflow furnace 44, and a second reflow furnace 45 A plurality of heating furnaces are arranged in series. Each of these heating furnaces is shown in Figure 2. It has an internal structure. 46 is a cooling fan.

[0021] At the bottom of each of the heating furnaces, there is a multi-layer structure as a cold air blowing part for blowing cold air into the furnace. Hole nozzles 51 are provided, and cold air supply piping 52 is connected to each of these porous nozzles 51. A cold air volume adjustment valve is connected to each pipe to adjust the cold air flow rate in each conduit. 53 are provided for each.

[0022] As shown in FIG. 3, each of the cold air volume adjustment valves 53 is for on/off use. It is connected to a manifold 55 via a solenoid valve 54, and this manifold 55 has a main shutoff valve 56, It is connected to a pneumatic source 58 such as a compressor via a hose joint 57 or the like.

[0023] Next, the operation of this embodiment will be explained.

[0024] Due to forced convection heat from hot air circulating through the heating unit 14 in each heating furnace, The component-mounted board W transported through each heating furnace is heated, and the solder paste on the board is heated. Reflow.

[0025] At that time, in the first preheat furnace 41 and the first reflow furnace 44, the infrared shielding plate By opening 23, the infrared rays generated from the heater 22 are irradiated onto the substrate W. , blows hot air heated by the heater 22 onto the substrate W, radiating heat from infrared rays and hot air. The component mounting board W is heated using forced convection heat.

[0026] On the other hand, in the second preheat furnace 42, the third preheat furnace 43, and the second reflow furnace 45, , by closing the infrared shielding plate 23 below the heater 22, the substrate is removed from the heater 22. Shields infrared rays irradiated to W. Then, components are mounted using only forced convection heat of hot air. The mounting substrate W is heated.

[0027] Also, when changing the type of component mounting board W, for example, if low melting point solder is used, When sending substrates to the conveyor 31, it is necessary to lower the set temperature in the furnace, and It is necessary to quickly lower the temperature inside the furnace after the If other parts are installed, it is necessary to protect them from high heat. , cold air (room temperature air) is blown into the furnace from the porous nozzle 51.

[0028] At that time, the solenoid valves 54 are selectively opened for the five furnaces 41, 42, 43, 44, and 45 to take appropriate action. The required flow is supplied to the cold air blowing section 51 of the heating furnace through the cold air volume adjustment valve 53. It selectively supplies a large amount of cold air under pressure and blows the cold air only into the heating furnace where you want to lower the temperature inside the furnace. nothing.

[0029] When adjusting the cold air volume adjustment valve 53, the temperature detected by the temperature sensor 33 is If you check the temperature inside the furnace using the temperature controller on the operation panel, you can easily set conditions such as the flow rate of cold air. can be completed quickly. Once this condition setting is completed, the rest is heating. The solenoid valve 54 is controlled on/off by the temperature sensor 33, and the temperature inside the furnace is automatically controlled.

[0030] In Figure 4, solid line A indicates the temperature of the board using 63Sn/37Pb solder. The dotted line B shows the low melting profile of 42Sn/42Pb/14Bi/2Ag. The temperature profile of the board using point solder is shown, but for this low melting point solder blows cold air into the furnace from the cold air blowing section 51 of the reflow furnaces 44 and 45, and performs the reflow process. Set the temperature to a relatively low temperature.

[0031] In addition, if all the solenoid valves 54 are opened, the temperature inside the furnaces of all the furnaces 41, 42, 43, 44, and 45 will be lowered. Needless to say, you will be disappointed.

[0032]

[Effect of the idea]

According to the invention described in claim 1, the heating furnace includes a cold air blowing section that blows cold air into the furnace. Because of this, the temperature inside the furnace is controlled by the cold air blown into the furnace from this cold air blowing part. Forced lowering reduces wasted time spent setting furnace conditions when changing workpieces, etc. It can be used for high-mix, low-volume production, and also shortens the cooling time of the equipment after work is completed. Work time can be further shortened and productivity and work efficiency can be improved.

[0033] According to the invention described in claim 2, a plurality of processes are performed along the conveyor that conveys the workpiece. The heating furnaces are arranged, and each of these heating furnaces has a cold air blowing section that blows cold air into the furnace. A cold air supply pipe is connected to each of these cold air blowing parts, and Since a cold air volume adjustment valve is installed in each pipe, the required amount of cold air from the heating furnace can be adjusted. By selectively supplying cold air at the required flow rate to the blowing section, the temperature profile of the workpiece can be adjusted. can be optimized.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view in the transport direction showing an embodiment of the air reflow device of the present invention.

FIG. 2 is a cross-sectional view in the transverse direction of the air reflow device.

FIG. 3 is a piping diagram for supplying cold air of the air reflow device.

FIG. 4 is a graph showing a temperature profile of a substrate heated by the air reflow device.

[Explanation of symbols]

W work 31 Conveyor 41～45 Heating furnace 51 Cold air blower 52 Cold air supply piping 53 Cold air volume adjustment valve

──────────────────────────────────────────────── ─── Continuation of front page (72) Creator Nikki Masuda 591-11, Kamihirose Higashikubo, Sayama City, Saitama Prefecture Tamura Manufacturing Co., Ltd. machine factory (72) Creator Nobuhide Abe 591-11, Kamihirose Higashikubo, Sayama City, Saitama Prefecture Tamura Manufacturing Co., Ltd. machine factory

Claims (2)

[Scope of utility model registration request] Claim 1: In an air reflow apparatus for reflow soldering workpieces conveyed through a heating furnace using forced convection heat generated by hot air circulating through a heater in the heating furnace, cold air is blown into the heating furnace. An air reflow device characterized by being provided with a cold air blowing section. Claim 2: In an air reflow device for reflow soldering workpieces conveyed through a heating furnace by forced convection heat generated by hot air circulating through a heater in the heating furnace, the workpieces are arranged along a conveyor conveying the workpieces. A plurality of heating furnaces, a cold air blowing section provided in each of these heating furnaces and blowing cold air into the furnace, and a cold air volume adjustment valve connected to each of these cold air blowing sections, respectively, in each conduit. An air reflow device characterized by comprising cold air supply piping provided in each of the air reflow devices.