Apparatus and method having a closed-loop IR camera thermal detection system

Abstract

An apparatus for bonding electronic components to electronic substrates includes a chamber housing having a tunnel penetrating multiple processing zones, a conveyor for transporting the electronic substrates in the tunnel through the multiple processing zones, and a thermal detection system including at least one temperature sensor coupled to the chamber housing. The at least one temperature sensor detects the temperature of the electronic substrates passing in close proximity to the at least one temperature sensor. The apparatus further includes a controller coupled to the multiple processing zones, the conveyor, and the thermal detection system. The controller receives temperature data from the thermal detection system.

Description

Technical Field

[0001] This application generally relates to the surface mounting of electronic components on printed circuit boards by using assembly processes such as reflow processes, wave soldering processes, and / or selective soldering processes, and more particularly to an apparatus configured to control the heat applied to a printed circuit board during an assembly process.

Background Art

[0002] In the manufacture of printed circuit boards, electronic components are often surface-mounted on a bare substrate by a process known as "reflow soldering". In a typical reflow soldering process, a pattern of solder paste is deposited on the circuit board, and the leads of one or more electronic components are inserted into the deposited solder paste. Thereafter, the circuit board is passed through a furnace where the solder paste is reflowed (i.e., heated to the melting or reflow temperature) in a heating zone and then cooled in a cooling zone to electrically and mechanically connect the leads of the electronic components to the circuit board. The term "circuit board" or "printed circuit board" as used herein includes any type of substrate assembly for electronic components, including, for example, a wafer substrate.

[0003] As described above, today's reflow furnaces have a heating chamber and a cooling chamber. In order to achieve a consistent reflow process profile, the heat applied to the electronic components and the circuit board is precisely controlled to ensure proper mechanical and electrical connection of the electronic components to the circuit board.

[0004] Furthermore, in the manufacturing of printed circuit boards, electronic components can be mounted onto the board by a process known as "wave soldering." In a typical wave soldering machine, the circuit board moves along an inclined path by a conveyor, passing through a flux application station, a preheating station, and finally the wave soldering station. At the wave soldering station, a wave of solder is ejected upward (by a pump) through a wave soldering nozzle and comes into contact with the portion of the printed circuit board to be soldered. Similar to reflow ovens, wave soldering machines (and selective soldering machines) require precise heat control in each zone to ensure proper mechanical and electrical connection of electronic components to the circuit board.

[0005] For both reflow ovens and wave (and selective) soldering machines, thermal control within each equipment zone is crucial for optimal performance. For example, undesirable temperature fluctuations can lead to circuit board warping and unreliable connections between electronic components and the circuit board. [Overview of the project]

[0006] One aspect of the present disclosure relates to a reflow oven for bonding electronic components to an electronic substrate. In one embodiment, the reflow oven comprises a chamber housing having a tunnel through a plurality of processing zones, a conveyor for transporting electronic substrates in the tunnel through the plurality of processing zones, and a thermal detection system having at least one temperature sensor coupled to the chamber housing. The at least one temperature sensor detects the temperature of the electronic substrate as it passes in the immediate vicinity of the at least one temperature sensor. The reflow oven further comprises a controller coupled to the plurality of processing zones, the conveyor and the thermal detection system. The controller receives temperature data from the thermal detection system.

[0007] The embodiment of the reflow oven may further include the at least one temperature sensor having at least one sensor assembly. The at least one sensor assembly may comprise a support structure, a support bracket coupled to the support structure, and an IR camera fixed to the support bracket. The support structure may comprise a shroud mounted on the mounting plate. The shroud may be configured to surround an opening at the top of the tunnel to allow the IR camera to detect the temperature of the tunnel. The support bracket may comprise a port for connection to an inert gas source. The support bracket may comprise a glass cover protecting the IR camera. The support bracket may be configured to mount the IR camera at a desired height and orientation at the top of the tunnel to achieve a full field of view. The at least one sensor assembly may comprise multiple IR cameras to measure two or more distinct locations among selected locations within the tunnel. The thermal detection system may be configured with the controller to provide closed-loop control of the zone temperatures of the multiple processing zones using the sensor assembly. The at least one sensor assembly can be configured to acquire temperature data within a particular processing zone of the reflow soldering furnace at a specific electronic substrate level. The temperature data can be used to provide electronic substrate traceability, where data relating to a particular electronic substrate is provided on a display associated with the controller. The temperature data can be used to discover hot spot zones / levels within the reflow soldering furnace. The temperature data can be used to optimize the performance of the reflow soldering furnace, and / or to provide downstream inputs to processing equipment, and / or to determine the start and end times of scans performed on the electronic substrate by the at least one sensor assembly, and / or to generate upper and lower electronic substrate profiles of the electronic substrate. The closed-loop control may include controlling the speed of the conveyor within the plurality of processing zones.Each electronic circuit board may be provided with a barcode that is scanned by a barcode scanner. The controller may be configured to enter a scan mode to measure the temperature of the components on the electronic circuit board as the electronic circuit board moves along the conveyor through the reflow soldering furnace.

[0008] Another aspect of the present disclosure relates to a method for bonding electronic components to an electronic substrate in a reflow oven. In one embodiment, the method includes transporting the electronic substrate through a chamber housing having a tunnel through a plurality of processing zones; detecting the temperature of the electronic substrate as it passes in the vicinity of a thermal detection system having at least one temperature sensor coupled to the chamber housing; and receiving temperature data from the thermal detection system using a controller coupled to the plurality of processing zones, the conveyor and the thermal detection system.

[0009] Embodiments of this method may further include scanning barcodes associated with each substrate using a barcode scanner, and / or controlling the reflow soldering furnace to implement a scan mode for measuring the temperature of components on the electronic substrate as the electronic substrate moves along the conveyor through the reflow soldering furnace. The thermal detection system may be configured with the controller to provide closed-loop control of zone temperatures for the plurality of processing zones using the sensor assembly. The at least one sensor assembly may be configured to acquire temperature data within a particular processing zone of the reflow soldering furnace at a specific electronic substrate level location. The temperature data can be used to provide electronic substrate traceability, where data about a particular electronic substrate is provided on a display associated with the controller. The temperature data can be used to discover hotspot zones / levels within the reflow soldering furnace. The temperature data can be used to optimize the performance of the reflow soldering furnace, and / or provide downstream inputs to processing equipment, and / or determine the start and end times of scans performed on the electronic substrate by the at least one sensor assembly, and / or generate upper and lower electronic substrate profiles of the electronic substrate. The closed-loop control may include controlling the speed of the conveyor within the plurality of processing zones. The method may further include scanning a barcode associated with each substrate using a barcode scanner. The method may further include controlling the reflow soldering furnace to enable a scan mode for measuring the temperature of components on the electronic substrate as the electronic substrate moves along the conveyor through the reflow soldering furnace.

[0010] A further aspect of the present disclosure relates to a wave soldering machine or selective soldering machine for joining electronic components to an electronic substrate. In one embodiment, the reflow oven comprises a chamber housing having a tunnel through a plurality of processing zones, a conveyor for transporting electronic substrates in the tunnel through the plurality of processing zones, and a thermal detection system comprising at least one temperature sensor coupled to the chamber housing. The at least one temperature sensor detects the temperature of the electronic substrate as it passes immediately in front of the at least one temperature sensor. The wave soldering machine or selective soldering machine further comprises a controller coupled to the plurality of processing zones, the conveyor and the thermal detection system. The controller receives temperature data from the thermal detection system. The at least one temperature sensor may include at least one sensor assembly. The at least one sensor assembly may comprise a support structure, a support bracket coupled to the support structure, and an IR camera fixed to the support bracket. The support structure may comprise a mounting plate positioned above the tunnel and a shroud mounted on the mounting plate. The shroud may be configured to surround the opening of the mounting plate to enable the IR camera to detect the temperature of the tunnel. The support bracket may have a port for connecting to an inert gas source. The support bracket may have a glass cover to protect the IR camera. The support bracket may be configured to mount the IR camera at a desired height and orientation above the tunnel to achieve a full field of view. The at least one sensor assembly may comprise multiple IR cameras to measure two or more distinct locations among selected locations within the tunnel. The thermal detection system may be configured with the controller to provide closed-loop control of the zone temperatures of the multiple processing zones using the at least one sensor assembly.The at least one sensor assembly can be configured to acquire temperature data within a specific processing zone of the reflow soldering furnace at a specific electronic board level location. The temperature data can be used to provide electronic board traceability, where data relating to a specific electronic board is provided on a display associated with the controller. The temperature data can be used to discover hot spot zones / levels within the wave soldering machine or selective soldering machine. The temperature data can be used to optimize the performance of the wave soldering machine or selective soldering machine, and / or to provide downstream inputs to the processing equipment, and / or to determine the start and end times of scans performed on the electronic board by the at least one sensor assembly, and / or to generate upper and lower electronic board profiles of the electronic board. The closed-loop control can include controlling the speed of the conveyor within the plurality of processing zones. The electronic boards may each have a barcode that is scanned by a barcode scanner. The controller can be configured to implement a scan mode to measure the temperature of components on the electronic board as the electronic board moves along the conveyor through the wave soldering machine or selective soldering machine.

[0011] Another aspect of the present disclosure relates to a method for bonding electronic components to an electronic substrate in a wave soldering machine or a selective soldering machine. In one embodiment, the method includes transporting an electronic substrate through a chamber housing having a tunnel through a plurality of processing zones; detecting the temperature of the electronic substrate as it passes in the vicinity of a thermal detection system having at least one temperature sensor coupled to the chamber housing; and receiving temperature data from the thermal detection system using a controller coupled to the plurality of processing zones, the conveyor and the thermal detection system.

[0012] Embodiments of this method may further include scanning barcodes associated with each substrate using a barcode scanner, and / or controlling the machine to implement a scan mode for measuring the temperature of components on the electronic substrates as the electronic substrates move along the conveyor through the machine. The thermal detection system may be configured with the controller to provide closed-loop control of zone temperatures for the plurality of processing zones using the sensor assembly. The at least one sensor assembly may be configured to acquire temperature data within a particular processing zone of the machine at a specific electronic substrate level location. The temperature data can be used to provide electronic substrate traceability, where data about a particular electronic substrate is provided on a display associated with the controller. The temperature data can be used to discover hotspot zones / levels within the machine. The temperature data can be used to optimize the performance of the machine, and / or provide downstream inputs to processing equipment, and / or determine the start and end times of scans performed on the electronic substrates by the at least one sensor assembly, and / or generate upper and lower electronic substrate profiles of the electronic substrates. The closed-loop control may include controlling the speed of the conveyor within the plurality of processing zones.

[0013] Another aspect of the present disclosure relates to an apparatus for bonding electronic components to an electronic substrate. In one embodiment, the apparatus comprises a chamber housing having a tunnel through a plurality of processing zones, a conveyor for transporting electronic substrates in the tunnel through the plurality of processing zones, and a thermal detection system having at least one temperature sensor coupled to the chamber housing. The at least one temperature sensor detects the temperature of the electronic substrate as it passes in the immediate vicinity of the at least one temperature sensor. The apparatus further comprises a controller coupled to the plurality of processing zones, the conveyor and the thermal detection system. The controller receives temperature data from the thermal detection system.

[0014] A further aspect of the present disclosure relates to a method for bonding electronic components to an electronic substrate in an apparatus. In one embodiment, the method includes transporting an electronic substrate through a chamber housing having a tunnel through a plurality of processing zones; detecting the temperature of the electronic substrate as it passes in the vicinity of a thermal detection system having at least one temperature sensor coupled to the chamber housing; and receiving temperature data from the thermal detection system using a controller coupled to the plurality of processing zones, the conveyor and the thermal detection system.

[0015] The attached drawings are not intended to be drawn to exact scale. In the drawings, each identical or nearly identical component shown in each drawing is represented by the same reference numeral. For clarity, not all components are labeled in all drawings. [Brief explanation of the drawing]

[0016] [Figure 1] This is a perspective view of a reflow soldering furnace according to one embodiment of the present disclosure. [Figure 2] Figure 1 is a schematic diagram of a reflow soldering furnace. [Figure 3] This is a perspective view of a portion of a reflow soldering furnace showing a thermal detection system according to one embodiment of the present disclosure. [Figure 4] Figure 3 is a perspective view of the IR camera assembly of the thermal detection system shown. [Figure 5] This is a perspective view of an IR camera assembly mounted on the upper wall of the tunnel in a reflow soldering furnace. [Figure 6] This is a perspective view of an IR camera mounted on a gantry in another embodiment of a thermal detection system. [Figure 7] This is a schematic diagram of a wave soldering machine according to one embodiment of the present disclosure. [Figure 8] This is a side view of a wave soldering machine with its external packaging removed to reveal its internal components. [Figure 9] This is a perspective view of an IR camera assembly for a thermal detection system associated with a wave soldering machine. [Figure 10] Figure 9 is a perspective view of the IR camera assembly shown. [Modes for carrying out the invention]

[0017] Solder paste is routinely used in printed circuit board assemblies to bond electronic components to the circuit board. Solder paste comprises solder for joint formation and flux for preparing the metal surface for soldering. Solder paste can be deposited onto metal surfaces (e.g., electronic pads) on the circuit board by using any number of application methods. In one example, a stencil printer may utilize a squeegee to press the solder paste through a metal stencil placed on the exposed circuit board surface. In another example, a dispenser may supply the solder paste material onto a specific area of ​​the circuit board. The wires of the electronic components are aligned with the solder deposit and pressed into it to form the assembly. In the reflow soldering process, the solder is then heated to a temperature sufficient to melt and cooled to permanently bond the electronic components to the circuit board electrically and mechanically. Solder typically comprises alloys with a melting temperature lower than the melting temperature of the metal surfaces being bonded. Furthermore, the temperature must be low enough not to damage the electronic components. In certain embodiments, the solder may be a tin-lead alloy. However, solder made from lead-free materials may also be used.

[0018] Temperature control of the soldering process is very important. In one embodiment of the present disclosure, a thermal detection system having several infrared (IR) cameras is used to precisely measure the temperature of a circuit board within strategic locations of a reflow soldering furnace. Using the information obtained from the IR cameras of the thermal detection system, closed-loop control of the reflow furnace can be provided to ensure proper connection between the electronic components and the circuit board. Other types of temperature measurement devices can be utilized instead of the IR cameras. For example, a laser temperature sensor can be used as part of the thermal detection system. Furthermore, the techniques described herein can be used in other types of circuit board processing equipment, such as wave soldering machines and selective soldering machines, to achieve improved temperature control.

[0019] Now, for the purpose of illustration only and not to limit generality, the present disclosure will be described in detail with reference to the accompanying drawings. The application of the present disclosure is not limited to the details of the structure and arrangement of the components shown in the following description or in the drawings. The principles shown in the present disclosure allow for other embodiments and can be implemented or executed in various ways. Also, the terms and technical terms used herein are for the purpose of explanation and should not be considered as limiting. The use of "including", "comprising", "having", "containing", "involving" and their variants herein is intended to include additional items together with the items listed previously and their equivalents.

[0020] Reflow soldering furnace In the reflow process, the printed circuit board is heated for approximately 3 to 5 minutes according to a predetermined temperature profile. The complete assembly (including the board material, components, and solder paste) should reach the minimum reflow temperature but should not be overheated. Overheating can damage components and cause defects in the solder. To achieve this heating curve, the reflow soldering furnace includes multiple heating and cooling zones. These zones blow high-temperature or low-temperature gases towards the circuit board. The gas temperature setpoints of these zones, combined with the conveyor speed, define the final heating profile of the circuit board assembly.

[0021] To ensure the reflow soldering furnace operates correctly, thermocouples are attached to the printed circuit board to record the board's temperature over time. Thermocouples are placed at the lowest and highest temperature locations on the circuit board assembly, and above critical components, to ensure components do not overheat. Once the setpoint and conveyor speed are determined to be within acceptable specifications, the furnace includes a control unit and thermal probes to maintain zone temperatures within acceptable limits. During production, circuit boards with thermocouples may pass through the reflow soldering furnace to ensure all predetermined conditions remain within acceptable specifications. A drawback of existing process control is the lack of temperature control over the circuit board assembly during the reflow process. While component and solder joint inspections of the circuit board are performed after soldering, they are not verified during the heating time of the circuit board.

[0022] Existing process control relies on maintaining zone temperatures and conditions within specifications using thermal probes that measure gas temperature but not the actual temperature within the circuit board assembly. Thermal profiling hardware is available with software tools that help define, measure, monitor, and improve the thermal processes in electronic manufacturing services. These systems enable better process control, making reflow soldering furnaces smarter and reducing defects. Intelligent software makes changes to furnace settings when it is necessary to ensure consistent board temperature and solder quality.

[0023] Despite the intelligent system and process control of the reflow soldering furnace, the actual temperature of the circuit board assembly is not verified during soldering. Implementing a thermal detection system that can acquire the thermal image of the circuit board assembly during reflow adds value to the process control for preventing component damage and reducing solder defects.

[0024] Embodiments of the present disclosure relate to a thermal detection system in which several IR camera assemblies are strategically positioned within a reflow soldering furnace to obtain closed-loop temperature control of the furnace. In one embodiment, the lens of the IR camera assembly is kept clean to enable the creation of an accurate temperature image. The IR camera assembly includes a special chamber in front of the lens, into which nitrogen is purged to create an overpressure and prevent flux-contaminated gas from condensing on the lens. Another method disclosed herein for maintaining a clean lens from flux residues is to have a transparent foil in front of the lens on a roll system. When the foil gets dirty, the roll turns to present a new clean transparent section. Additionally, the reflow soldering furnace can include a catalyst for cleaning the gas within the zone.

[0025] Embodiments of a thermal detection system include the use of thermal imaging as part of a closed-loop system that controls the reflow process. Data from the thermal imaging is integrated into the intelligent control system of the reflow soldering furnace. The camera can be a 3D thermal camera or a conventional 2D camera. The generated data (temperatures of different areas, components, solder paste, and substrate materials) can be used for traceability and corrective actions. Multiple cameras may be present in the reflow process. A thermal image scan is a snapshot of the reflow process. However, if multiple cameras are installed, the snapshot collections can be used to calculate important process parameters such as the time above the liquidus line and peak temperature. This data can be correlated with defect levels, and preventive actions can be sent to a printer, dispenser, or pick-and-place machine to make necessary changes.

[0026] Image scanning can also signal deviations, and the reflow soldering furnace can respond accordingly. If the temperature is too low or too high, various actions can be taken, such as changing the conveyor speed or adjusting the fan speed of one or more heating zones to increase or decrease heat conduction. Other methods of temperature compensation include temporarily stopping the circuit board to increase the temperature, or, if the circuit board is too hot, pushing the circuit board through the zone to achieve a shorter heating time. These fine-tuning adjustments require free space between the circuit boards. If a board is too cold, an IR lamp can be placed in the zone behind the scanner to heat that particular circuit board more quickly to meet specifications. A furnace transfer tracking system should track the position of the circuit boards within the reflow soldering furnace to perform scans at the appropriate moments. Typically, the conveyor has an encoder or other device that controls the speed and defines the position of the circuit boards. In one embodiment, additional sensors can be placed near the scanner to locate the circuit boards. The circuit board can be configured to have barcodes, RFID tags, or some other type of identification information traceability.

[0027] Embodiments of the thermal detection system acquire image scans to indicate component alignment during the reflow process and analyze component movement defects. For example, if multiple scanners are present in the reflow soldering furnace, the position within the furnace can be defined by where the component moves, which can help avoid this type of defect. Further actions may include replacing fans or reducing fan speed in specific zones of the furnace.

[0028] Embodiments of the thermal detection system are further configured to acquire temperature profiles of circuit boards at strategic points within a reflow soldering furnace. This is more accurate than thermocouple profiling, which only returns the temperature of the probe. Secondly, the probe location may not be the most critical point on the circuit board assembly, and thermocouple mounting is extremely important. Thermocouples may loosen after several runs, while IR cameras maintain accuracy over time and are not limited by the number of samples, provided the lens remains clean.

[0029] Figure 1 shows one embodiment of an exemplary reflow soldering apparatus for soldering circuit board assemblies. Such apparatus may also be called a reflow oven or reflow soldering oven in the field of printed circuit board manufacturing and assembly. The reflow soldering oven is generally shown as 10 in Figure 1 and comprises a reflow oven chamber 12 in the form of an adiabatic tunnel that defines a passage for preheating, reflowing, and then cooling the solder on the circuit board as it passes through it. In one example, the reflow oven chamber 12 extends across a plurality of heating zones, including three preheating zones 14, 16, 18 followed by three immersion zones 20, 22, 24, each zone comprising an upper heater 26 and a lower heater 28, respectively. Following the immersion zones 20, 22, 24 are, for example, four spike zones 30, 32, 34, 36, each also comprising heaters 26, 28. Finally, after the spike zones 30, 32, 34, and 36, there are three cooling zones 38, 40, and 42. Other reflow soldering furnace configurations can be provided.

[0030] The circuit board assembly 44, including the deposited solder paste and electronic components, passes through each zone (e.g., from left to right in Figure 1) of the adiabatic reflow oven chamber 12 on a fixed-speed conveyor (indicated by 46 in the dashed line in Figure 1), thereby enabling progressive control of the preheating, reflow, and post-reflow cooling of the circuit board assembly. It should be understood that the fixed-speed conveyor 46 can be divided between zones to embody a variable-speed conveyor. In the preliminary preheating zones 14, 16, and 18, the board assembly is heated from ambient temperature to the flux activation temperature, which can be in the range of approximately 130°C to 150°C for lead-based solder and can be higher for lead-free solder.

[0031] In immersion zones 20, 22, and 24, temperature fluctuations across the circuit board assembly are stabilized, and the activated flux allows time for the component wires, electronic pads, and solder powder to be cleaned before reflow. In addition, VOCs in the flux are vaporized. The temperature in immersion zones 20, 22, and 24 is typically about 140°C to 160°C for lead-based solder and higher for lead-free solder. In certain embodiments, the circuit board assembly can spend about 30 to 45 seconds passing through immersion zones 20, 22, and 24.

[0032] In spike zones 30, 32, 34, and 36, the temperature rises rapidly to above the solder's melting point in order to reflow the solder. The melting point of eutectic or quasi-eutectic tin-lead solder is approximately 183°C, and the reflow spikes are typically set to be about 25°C to 50°C above the melting point to exceed the paste range of the molten solder. For lead-based solders, the typical maximum temperature in the spike zones is in the range of about 200°C to 220°C. Temperatures above about 225°C may cause flux baking, damaging components and / or sacrificing joint integrity. Temperatures below about 200°C may prevent the joint from reflowing completely. In one embodiment, the circuit board assembly is typically kept above the reflow temperature in spike zones 30, 32, 34, and 36 for about 1 minute.

[0033] Next, in cooling zones 38, 40, and 42, the temperature falls below the reflow temperature, and the circuit board assembly is cooled sufficiently to maintain joint integrity by solidifying the joints before the circuit board assembly leaves the reflow oven chamber 12.

[0034] A flux extraction / filtration system (not shown) may be provided to remove contaminants from the gas generated by the reflow soldering furnace 10. In one embodiment, an input gas duct may be connected to or between zones selected to provide fluid communication from the reflow furnace chamber 12 to the flux extraction / filtration system. An output gas duct may be connected to or between zones selected to provide fluid communication from the flux extraction / filtration system back to the reflow furnace chamber 12. During operation, a vapor flow is drawn from the reflow furnace chamber 12, through the input gas duct, through the system, and then back to the reflow furnace chamber through the output gas duct. Similar configurations of the input gas duct, system, and output gas duct may also be positioned to draw vapor flows from or between other zones of the reflow soldering furnace 10.

[0035] The reflow soldering furnace 10 further comprises a controller 50 that automates the operation of several stations of the reflow soldering furnace in a known manner, including, but not limited to, upper heaters 26 and lower heaters 28 associated with preheating zones 14, 16, 18, immersion zones 20, 22, 24, spike zones 30, 32, 34, 36, and cooling zones 38, 40, 42. As shown in the figure, the controller 50 may include a display 52 with a user interface that allows an operator of the reflow soldering machine 10 to control the operation of the machine.

[0036] In a particular embodiment, the controller 50 may be configured to use a personal computer having an appropriate operating system, such as the Microsoft Windows® operating system provided by Microsoft, along with application-specific software that controls the operation of the reflow soldering furnace 10. The controller 50 may be networked with a master controller used to control the production line for manufacturing circuit boards. As will be described in more detail below, the information obtained by the thermal sensing system can be used by the controller 50 to optimize the performance of the reflow soldering furnace 10. This optimization includes eliminating warping and achieving better and more reliable fastening of electronic components onto the circuit board assembly.

[0037] Referring to Figure 3, the reflow soldering furnace 10 includes a thermal detection system, generally indicated by 60, which detects heat within the furnace zones. In the illustrated embodiment, the thermal detection system 60 comprises several sensor assemblies, for example three, including an IR camera assembly, each generally indicated by 62. In this example, the first IR camera assembly 62a is positioned between the third zone (preheating zone) and the fourth zone (immersion zone) of the reflow soldering furnace 10, the second IR camera assembly 62b is positioned between the sixth zone (immersion zone) and the seventh zone (spike zone), and the third IR camera assembly 62c is positioned between the ninth zone (spike zone) and the tenth zone (cooling zone). It should be understood that the IR camera assemblies 62 may be placed anywhere within the reflow soldering furnace 10 to optimize the performance of the reflow soldering furnace.

[0038] Each IR camera assembly 62 is strategically positioned to measure the temperature of the circuit board assembly 44 as it passes between zones to ensure that the circuit board assembly is properly conditioned before processing. The information acquired from each IR camera assembly 62 is communicated to the controller 50, which provides closed-loop processing for subsequent circuit board assemblies passing through the reflow soldering furnace 10.

[0039] Referring further to Figures 4 and 5 for the application of the reflow soldering furnace, each IR camera assembly 62 comprises a shroud 64 mounted on the upper wall 66 of the chamber 12 of the reflow soldering furnace 10. The shroud 64 penetrates an opening formed in the upper wall 66 of the chamber 12, allowing the IR camera assembly 62 to detect the temperature of the tunnel. The support structure further comprises a support bracket 68 mounted on the shroud 64 at the top of the shroud. The support bracket 68 comprises a port 70 for connecting to a nitrogen (N2) source to provide an inert atmosphere inside the shroud 64. The support bracket 68 further comprises an input port 72 for connecting a sensor to the support bracket.

[0040] The IR camera assembly 62 further includes a temperature sensor that embodies an IR camera 74, which is supported in the operating position by a support bracket 68. A cable 76 is fixed to the input port 72, connecting the IR camera 74 to the controller 50. As described above, any type of temperature sensor may be used to measure the temperature of the circuit board assembly moving within the tunnel (chamber 12) of the reflow soldering furnace 10. The IR camera 74 has a field of view directed towards the tunnel (chamber 12) of the reflow soldering furnace 10 through the shroud 64. In this configuration, the IR camera 74 of the IR camera assembly 62 detects the temperature of the circuit board assembly moving within the tunnel (chamber 12) of the reflow soldering furnace 10 and communicates this information to the controller 50. The data acquired from the thermal detection system 60 can be used for various purposes, which are described in more detail below.

[0041] Referring to Figure 6, an alternative embodiment of the sensor assembly is generally shown as 80. As shown, the sensor assembly 80 comprises a gantry 82 and a temperature sensor comprising an IR camera 84 connected to the gantry and controller 50. In this configuration, the gantry 82 moves the IR camera 84 along the width of the tunnel (chamber 12) under the control of the controller 50 to acquire temperature data across the width of the printed circuit board assembly as it passes through the reflow soldering furnace 10. The sensor assembly 80 may further include a shroud (not shown) to keep the IR camera 84 in an inert (clean) atmosphere.

[0042] Wave soldering machine In the wave soldering process, there are several process steps. One step is flux application, which involves spraying flux onto the solder side (bottom) of the printed circuit board assembly to clean it. After flux application, the printed circuit board assembly is transferred to a preheating unit. The preheating unit can be implemented in various ways, such as a convection or radiant heater. The purpose is to heat the printed circuit board assembly to a predetermined temperature, typically measured on the solder destination side (upper board). The preheater activates the flux, and the circuit board assembly becomes hot enough that the solder does not solidify until it reaches the upper board. The printed circuit board assembly enters the solder wave. The soldering process consists of a heated solder tank that is maintained at the temperature required for the soldering process. Inside the tank, the solder wave is set up, and the printed circuit board assembly passes over the solder wave so that the bottom of the circuit board assembly is in contact with the solder wave.

[0043] The temperature of a circuit board assembly during preheating is typically measured using a pyrometer. This is usually done after the circuit board assembly has passed through the final preheating unit and just before it enters the solder wave station. However, because the pyrometer spot is limited, the data only covers one small area of ​​the entire board.

[0044] An embodiment of a thermal detection system with an IR camera is capable of scanning the entire printed circuit board assembly and acquiring temperature data from the printed circuit board assembly.

[0045] One embodiment of the thermal detection system includes an IR camera along with the wave soldering machine, after the final preheating unit. The data provided by the IR camera can be used for closed-loop process control. If the IR camera is positioned above the printed circuit board assembly within the preheating unit, the IR camera can provide information to modify the unit's preheater so that a specified temperature is achieved for the subsequent board before it enters the wave soldering station. As a result, the printed circuit board assembly can achieve an optimal temperature when it is soldered, thereby minimizing the risk of defects. The data is recorded and can be used for traceability, which can be combined with board identification information (such as a barcode or RFID) to correlate with defects or field failures during assembly.

[0046] Referring to Figure 7, an exemplary wave soldering machine is generally shown as 100. The wave soldering machine is used to apply wave solder to printed circuit board assemblies. As described above, the wave soldering machine 100 is one of several machines in a printed circuit board manufacturing / assembly line. As shown in the figure, the wave soldering machine 100 comprises a housing or frame 102 adapted to house the machine's components. In this configuration, a conveyor 104 delivers the printed circuit board assemblies 44 to the wave soldering machine 100 for processing.

[0047] Each circuit board assembly 44, upon entering the wave soldering machine 100, moves along an inclined path (e.g., 6 degrees to the horizontal) along the conveyor 102 through a tunnel 106. The wave soldering machine 100 includes a flux application station, generally indicated as 108, and a preheating station, generally indicated as 110, for conditioning the printed circuit board assemblies for wave soldering. Once conditioned (i.e., heated), the circuit board assembly 44 moves along the conveyor 102 to a wave soldering station (generally indicated as 112) for applying solder material to the printed circuit board assembly. A controller 114 is provided to automate the operation of several stations of the wave soldering machine 100, including, but not limited to, the flux application station 108, the preheating station 110, and the wave soldering station 112, in known manner.

[0048] Similar to the controller 50 associated with the reflow soldering furnace 10, the controller 114 of the wave soldering machine 100 can be configured to use a personal computer with an appropriate operating system, such as the Microsoft Windows® operating system provided by Microsoft, along with application-specific software that controls the operation of the wave soldering machine. The controller 114 can be networked with a master controller used to control the production line for manufacturing circuit boards. Similar to the reflow soldering furnace 10, information acquired by the thermal sensing system can be used by the controller 114 to optimize the performance of the wave soldering machine 100. This optimization includes eliminating warping and achieving better and more reliable fastening of electronic components onto circuit board assemblies.

[0049] Referring to Figure 8, the flux application station 108 is configured to apply flux to printed circuit board assemblies moving on the conveyor 104 after passing through the wave soldering machine 100. The preheating station 110 includes several preheaters (e.g., preheaters 110a, 110b, 110c) which are configured to gradually raise the temperature of the printed circuit board assemblies moving along the conveyor 104 through the tunnel 106 to prepare the printed circuit board assemblies for the wave soldering process. The wave soldering station 112 includes a wave soldering nozzle assembly that is in fluid communication with a solder material reservoir. A pump is provided in the reservoir to deliver molten solder material from the reservoir to the wave soldering nozzle assembly. Once soldered, the printed circuit board assemblies exit the wave soldering machine 100 via the conveyor 104 to another station on the production line, such as a pick-and-place machine.

[0050] In some embodiments, the wave soldering machine 100 may further include a flux management system, shown collectively as 116, which removes volatile contaminants from the tunnel 106 of the wave soldering machine. As shown in Figure 2, the flux management system 116 is located below the preheating station 110. In one embodiment, the flux management system 116 is supported by a housing 102 within the wave soldering machine 100 and is in fluid communication with the tunnel 106, which is schematically shown in Figure 2. The flux management system 116 is configured to receive contaminated gas from the tunnel 106, process the gas, and return clean gas to the tunnel. The flux management system 116 is particularly configured to remove volatile contaminants from the gas, especially in an inert atmosphere.

[0051] Referring to Figures 9 and 10, the wave soldering machine 100 includes a thermal detection system that detects heat within the machine's zones, for example, between the preheating station 110 and the wave soldering station 112. The thermal detection system includes a sensor assembly that embodies an IR camera assembly generally shown as 120. The IR camera assembly is strategically positioned to measure the temperature of the circuit board assembly 44 as it passes between the zones to ensure that the circuit board assembly is properly conditioned before processing. The information obtained from the IR camera assembly 120 is communicated to a controller 114, which provides closed-loop processing of subsequent circuit board assemblies passing through the wave soldering machine 100.

[0052] For applications involving a wave soldering machine, the IR camera assembly 120 comprises a support structure having a mounting plate 122 positioned above the tunnel 106 of the wave soldering machine 100, and a shroud 124 mounted on the mounting plate. The shroud 124 encloses an opening in the mounting plate 122 to allow the IR camera assembly to detect the temperature of the tunnel 106. The support structure further comprises a support bracket 126 mounted on the shroud 124 at the top of the shroud. The support bracket 126 comprises a port 128 for connecting to a nitrogen (N2) source to provide an inert atmosphere inside the shroud. The support bracket 126 further comprises an input port 130 for connecting a sensor to the support bracket.

[0053] The IR camera assembly 120 further comprises an IR camera 132 supported in an operating position by a support bracket 126. A cable 134 is fixed to the input port 130, connecting the IR camera 132 to the controller 114. As described above, any type of temperature sensor may be used to measure the temperature of the circuit board assembly within the tunnel 106 of the wave soldering machine 100. The IR camera 132 has a field of view directed towards the tunnel 106 of the wave soldering machine 100 through the shroud 124. In this configuration, the IR camera 132 of the IR camera assembly 120 detects the temperature of the circuit board assembly within the tunnel 106 of the wave soldering machine 100 and communicates this information to the controller 114.

[0054] Selective soldering machine In a selective soldering process, there are several process steps. First, there is a flux application step in which the printed circuit board (PCB) assembly is cleaned by spraying flux onto the solder side (bottom) of the PCB assembly. After flux application, the PCB assembly is transferred to a preheating unit. The preheating unit can be configured to include various heating concepts, such as convection or radiant heaters. The purpose of this process step is to heat the PCB assembly to a predetermined temperature, typically measured on the solder-side (top) of the PCB assembly. The flux is activated, and the PCB assembly becomes hot enough that the solder will not solidify until the selective soldering process is performed. Before implementing the thermal detection system of this disclosure, the temperature of the PCB assembly during preheating can be measured by a pyrometer, but the thermal information that the pyrometer generates regarding the PCB assembly is very limited.

[0055] After preheating, the printed circuit board assembly can be transferred to the soldering area and one of two soldering processes can be performed. In one soldering process, solder is applied using a small soldering nozzle configured for point-to-point soldering. In the other soldering process, solder is applied using a multi-wave plate that creates solder joints in a single dip.

[0056] Embodiments of the thermal detection system may include an IR camera (2D or 3D) in the selective soldering process. The data provided by this camera can be used for closed-loop process control. When the camera is positioned above the printed circuit board assembly during the preheating process, the temperature data acquired from the camera can provide information for changing the power of the unit so that a specified temperature is achieved when the selective soldering machine is ready to transfer the board to the soldering station. As a result, the printed circuit board assembly can achieve an optimal temperature when soldered, thereby minimizing the risk of defects. The data can be recorded and used for traceability, which can be linked to defects or field failures during assembly, in combination with board identification information such as barcodes or RFID.

[0057] An IR scanner can also be installed at the soldering station. In the case of a multi-wave dip process, a 2D or 3D camera can be configured to measure the temperature of the solder joint. Such a configuration can identify whether the solder has solidified (below its melting point) before the printed circuit board assembly moves to avoid stress at the solder joint. This data can also be used for traceability and process optimization purposes.

[0058] In point-to-point soldering processes, mounting an IR scanner above the soldering station can be beneficial for recording the state of the printed circuit board assembly and verifying that the temperature is within the temperature tolerance. This information can then be used to reduce defects and improve process control.

[0059] Other aspects of thermal detection systems In some embodiments, the support bracket includes an IR camera glass to protect the IR camera. Referring to Figure 9, a lens 140 is provided to protect the IR camera 132. Although shown with the IR camera assembly 120 of the wave soldering machine 100, it should be understood that the lens 140 or camera glass may also be provided with the IR camera assembly 62 associated with the reflow soldering furnace 10. Other types of materials may be provided to create a protective cover. The IR camera glass is positioned so that pressurized air moves across the IR camera glass to create an "air curtain" and prevent obstruction of the IR camera. In one embodiment, a movable film may be provided to protect the IR camera.

[0060] The lens 140 can be applied to an IR camera 74 associated with the reflow soldering furnace 10.

[0061] In some embodiments, the shroud can be configured to be connected to another inert fluid source.

[0062] In some embodiments, the shroud can be configured for a temperature-controlled fluid source to protect the IR camera.

[0063] In some embodiments, the support bracket can be configured to mount the IR camera at a desired height and orientation to achieve a full field of view. In the illustrated configuration, the IR camera is mounted on top of the tunnel of the reflow soldering furnace. However, the IR camera may also be mounted on the side of the tunnel of the reflow soldering furnace. In the case of side mounting, mirrors can be used to view the top and bottom of the circuit board passing through the tunnel.

[0064] In some embodiments, the IR camera can be mounted on a support structure that functions as a gantry for moving the camera across the circuit board. The IR camera may be positioned inside or outside the tunnel of a reflow soldering furnace.

[0065] In some embodiments, the IR camera assembly may comprise multiple IR cameras to measure two or more distinct locations within a selected position in the tunnel of a reflow soldering furnace.

[0066] In some embodiments, a one-dimensional line scan camera can be used to detect the temperature of the circuit board.

[0067] In some embodiments, a two-dimensional camera can be used to detect the temperature of the circuit board.

[0068] In some embodiments, an existing reflow soldering oven can be updated with an add-on kit that includes components of a thermal detection system, such as a mounting plate, shroud, support bracket, nitrogen connection, IR camera cable, and IR camera, and multiple IR camera assemblies. Software updates can be provided for the controller of the reflow soldering oven.

[0069] In some embodiments, the thermal detection system is configured with a controller to provide closed-loop control of zone temperatures using an IR camera assembly or other temperature detection device. Such closed-loop control allows an operator to monitor the circuit board temperature and locate hot spots on the circuit board both above and below the circuit board.

[0070] In some embodiments, the controller is configured with executable software that enables closed-loop control of various zones of the reflow soldering furnace.

[0071] In some embodiments, information obtained from the thermal detection system is collected and analyzed for future actions.

[0072] In some embodiments, the IR camera assembly of the thermal detection system acquires temperature data within a specific zone of a reflow soldering furnace at a specific substrate level location.

[0073] In some embodiments, the IR camera assembly of the thermal detection system provides a controller with data for process control of downstream parameters associated with the production line and / or addresses equipment issues.

[0074] In some embodiments, the printed circuit board has barcodes that are scanned by a barcode scanner or other type of identification system to track data for each circuit board.

[0075] In some embodiments, an IR camera assembly of the thermal detection system acquires temperature data used by a controller to provide closed-loop local heating to the required substrate zones. Real-time zone-to-zone temperature adjustment can be performed for the purpose of uniformity of circuit board temperature or a desired temperature profile.

[0076] In some embodiments, closed-loop processing of the circuit board may include controlling a conveyor to control the conveyor speed in one or more zones to optimize heat transfer. Fan blower speed may also be controlled. In one embodiment, the conveyor may include multiple sections corresponding to multiple zones, each conveyor section being controlled by a controller to control the speed of the conveyor section and, consequently, the temperature applied to the circuit board. Localized heating of the circuit board is achieved by this configuration.

[0077] In some embodiments, the data acquired from the thermal detection system can be used for a variety of purposes. For example, the data can be communicated to customers. The data can be used to provide customers with circuit board traceability where data related to a specific circuit board is correlated. The data can be used to discover hot spot zones / levels within a reflow soldering furnace. The data can be used to optimize the performance of a reflow soldering furnace. The data can be used to provide downstream inputs for processing equipment. The data can be used to determine the start and end times of scans performed on a circuit board by an IR camera assembly. The data can be used to generate upper and lower circuit board profiles to determine a particular board zone or level. The data can be used by customers for other analyses and stored on customer servers / networks or the cloud.

[0078] In some embodiments, the controller can be configured to implement a scan mode to measure the temperature of all components on the board as the board moves along the conveyor through the reflow soldering furnace.

[0079] In some embodiments, the thermal detection system is configured to perform thermal imaging during moiré analysis (strain / stress analysis) to correlate temperature hotspots with warp response.

[0080] In some embodiments, the thermal detection system detects hot and cold spots during reflow soldering, wave soldering, SRT rework, and selective soldering.

[0081] In some embodiments, a thermal detection system can be used to provide analysis to improve substrate design and functionality.

[0082] In some embodiments, a thermal detection system can be used to reduce voids in the reflow process.

[0083] In some embodiments, the thermal detection system achieves improved temperature control to reduce defects.

[0084] In some embodiments, the thermal sensing system incorporates integrated closed-loop control of zone temperatures in a reflow soldering furnace by utilizing multiple infrared (IR) camera assemblies at strategic locations to reduce warpage, identify hot spots, determine component overheating, obtain profile verification, and reduce voids.

[0085] In some embodiments, the thermal detection system is configured to include a self-sensing device having settings that self-adjust based on ambient conditions and the product being produced, thereby increasing visibility, productivity, traceability, and response time while reducing costs.

[0086] In some embodiments, thermal detection systems enable visibility and prescriptive real-time analysis across the supply chain, providing proactive intelligence for preventative action.

[0087] In some embodiments, the thermal detection system increases flexibility by managing complexity within the closed-loop system.

[0088] In some embodiments, connectivity is improved by an open architecture that develops standard or custom interfaces and data outputs. The architecture supports several MEMS.

[0089] In some embodiments, automation is improved by providing automatic replacement and replenishment of consumables to reduce operator errors and manpower.

[0090] In some embodiments, the thermal detection system achieves self-optimization by reducing operator intervention on machine parameters and providing closed-loop control to promote higher yield.

[0091] In some embodiments, maintenance is improved by providing predictive maintenance items based on the actual needs of the reflow soldering furnace or wave soldering machine. Furthermore, this improved maintenance replaces or reduces maintenance-based planning time.

[0092] In some embodiments, a controller associated with a reflow soldering furnace or wave soldering machine includes a controller adapted to control the operation of the furnace or machine based on operating parameters acquired by the controller. The controller may be configured to communicate with a controller associated with a production line. In one embodiment, the controller may be configured to communicate with another controller, for example, a controller associated with a production line, via a Controller Area Network (CAN) bus or other type of network. In other embodiments, a master controller may be provided to control the operation of controllers for individual devices associated with a production line. The controller may include a display operably coupled to the controller. The display is adapted to show operating parameters of a reflow soldering furnace or wave soldering machine, for example, temperature data through zones of the furnace or machine, or data associated with the solder level of the machine, without limit. Appropriate sensors may be provided to acquire such information. In place of or in addition to the above embodiments, the operating parameters may be displayed on a display provided in the reflow soldering furnace, a display provided in the wave soldering machine, and / or a display associated with a production line.

[0093] In other embodiments, material identification of an article, such as a circuit board, moving through a reflow soldering furnace or wave soldering machine may include a device for manipulating the article and a scanner for scanning and identifying the article. For example, a reflow soldering furnace or wave soldering machine may be configured to include a pinch wheel that rotates the circuit board to align a code or predetermined identification mark provided on the circuit board with a scanner provided on the furnace or machine. This system is configured to link material identification information associated with the circuit board to the recipe, production time, etc., of the reflow soldering furnace or wave soldering machine. In one embodiment, a barcode can be implemented to identify the article. For example, the barcode may include a 1D scanner for UPC codes, a 2D scanner for QRC codes, a printed label applied to the article, or a laser-etched label etched onto the article. In another embodiment, an RFID system can be implemented to identify the article. For example, the RFID system may include an RFID tag applied to the article and an RFID reader associated with the reflow soldering furnace or wave soldering machine. In the case of an RFID system, a line of sight between the reader and the article is not required. Furthermore, scanning is not necessary to identify all items within the mobile cart. In another embodiment, an imaging or vision system for identifying items can be implemented.

[0094] In some embodiments, a database is provided to track articles processed through a reflow soldering furnace or wave soldering machine. In one embodiment, the database may include an open application (app) architecture and may be configured to push data to the reflow soldering furnace or wave soldering machine. The furnace or machine may be configured to communicate with itself to push / pull data to the furnace or machine and / or production line, or to communicate directly with the production line. The database may include job information or material information. The database may further communicate with a manufacturing execution system (MES) associated with the production line, reflow soldering furnace and / or wave soldering machine. The MES system may be configured to know which materials are needed for a production run. A mobile cart may be configured to communicate with the MES system to coordinate the delivery of articles to the reflow soldering furnace or wave soldering machine.

[0095] The database can be further configured to retrieve information about items based on identification information, such as barcode numbers. In one embodiment, a central management system can be provided which a reflow soldering furnace or wave soldering machine is programmed to receive materials arriving from a mobile cart. The reflow soldering furnace or wave soldering machine is programmed to update the database to process circuit boards through the furnace or machine from a network, and the network is linked to an MES system.

[0096] The database can be further configured to store additional information, such as temperature data, the number of circuit boards being processed, and / or the amount of material consumed associated with the reflow soldering furnace or wave soldering machine. The database can be configured to store information locally or remotely, and can be configured to store data associated with one or more production runs.

[0097] The database can be configured to share predictive data when new production runs are anticipated or programmed. For example, with respect to storing information about temperature handling efficiency, the database can be configured to store information about temperature zone data, the number and type of circuit boards being processed, trigger alarms and / or reports when paste consumables need replenishment, signal inventory control systems associated with reflow soldering furnaces, wave soldering machines and / or production lines, analyze consumable usage based on operating parameters and actual usage and upstream / downstream equipment activity, predict replacement or maintenance, and predict future production run parameters correlated across multiple sites.

[0098] The database can be configured to store data associated with lot traceability. In addition, RFID or mechanical keying of the circuit boards is provided to ensure correct alignment / orientation / direction / front / back / up / down when these items are inserted into a reflow soldering furnace or wave soldering machine for processing. Low-cost readers can perform this function.

[0099] While several aspects of at least one embodiment of this disclosure have been described, it should be understood that various modifications, changes, and improvements will readily come to mind for those skilled in the art. Such modifications, changes, and improvements are intended to be part of this disclosure and to be within the spirit and scope of this disclosure. Accordingly, the above descriptions and drawings are merely illustrative. [Explanation of symbols]

[0100] 10 Reflow soldering oven 12 Reflow oven chamber 14 Preheating Zones 16 Preheating Zones 18 Preheating Zones 20 Immersion Zones 22 Immersion Zones 24 Immersion Zones 26 Upper heater 28 Lower heater 30 Spike Zones 32 Spike Zones 34 Spike Zones 36 Spike Zones 38 cooling zones 40 cooling zones 42 cooling zones 44 Printed circuit board assemblies 46 Fixed-speed conveyor 50 controllers 52 displays 60 Thermal Detection Systems 62 IR Camera Assembly 62a First IR camera assembly 62b Second IR camera assembly 62c Third IR Camera Assembly 64 Shroud 66 Upper wall 68 Support bracket 70 Ports 72 input ports 74 IR cameras 76 Cables 80 Sensor Assembly 82 Gantry 84 IR cameras 100-wave soldering machine 102 Housing 104 Conveyor 106 Tunnel 108 Flux application station 110 Preheating Station 110a Preheater 110b Preheater 110°C preheater 112 Stations 114 Controllers 116 Flux Management System 120 IR Camera Assembly 122 Plates 124 Shroud 126 Support bracket 128 ports 130 input ports 132 IR cameras 134 Cable 140 lenses

Claims

1. In a device for bonding electronic components to an electronic circuit board, A chamber housing with tunnels that penetrate multiple processing zones, A conveyor for transporting electronic substrates in the tunnel through the aforementioned multiple processing zones, A thermal detection system comprising at least one temperature sensor coupled to the chamber housing, wherein the at least one temperature sensor detects the temperature of the electronic substrate passing immediately in front of the at least one temperature sensor, A controller coupled to the plurality of processing zones, the conveyor, and the heat detection system, comprising a controller that receives temperature data from the heat detection system, The aforementioned at least one temperature sensor includes at least one sensor assembly, The at least one sensor assembly comprises a mounting plate positioned at the top of the tunnel and having an opening, a shroud mounted on the mounting plate and protruding upward from the mounting plate towards the tunnel, a support bracket coupled to the shroud, and an IR camera fixed to the support bracket. The shroud is a device that surrounds the opening of the mounting plate in order to enable the IR camera to detect the temperature of the tunnel.

2. The apparatus according to claim 1, wherein the support bracket is provided with a port for connecting to an inert gas source.

3. The apparatus according to claim 1, wherein the support bracket comprises a glass cover for protecting the IR camera.

4. The apparatus according to claim 1, wherein the support bracket is configured to mount the IR camera on the upper part of the tunnel at a desired height and orientation to achieve a complete field of view.

5. The apparatus according to claim 1, wherein the at least one sensor assembly comprises a plurality of IR cameras to measure two or more distinct locations among selected locations within the tunnel.

6. The apparatus according to claim 1, wherein the thermal detection system is configured using the controller to provide closed-loop control of the zone temperatures of the plurality of processing zones using the sensor assembly.

7. The apparatus according to claim 6, wherein the at least one sensor assembly acquires temperature data within a specific processing zone at a specific electronic circuit board level location.

8. The apparatus according to claim 7, in which temperature data is used to provide electronic substrate traceability, where data relating to a specific electronic substrate is provided on a display associated with the controller.

9. The apparatus according to claim 7, wherein temperature data is used to locate hot spot zones / levels within the chamber housing.

10. The apparatus according to claim 7, wherein temperature data is used to optimize the performance of the apparatus and / or to provide downstream input to processing equipment and / or to determine the start and end times of scans performed on an electronic circuit board by the at least one sensor assembly and / or to generate upper and lower electronic circuit board profiles of the electronic circuit board.

11. The apparatus according to claim 6, wherein the closed-loop control includes controlling the speed of the conveyor within the plurality of processing zones.

12. The apparatus according to claim 1, wherein each electronic circuit board is provided with a barcode that is scanned by a barcode scanner.

13. The apparatus according to claim 1, wherein the controller can be configured to realize a scan mode for measuring the temperature of components on the electronic circuit board as the electronic circuit board moves along the conveyor through the chamber housing.

Images