JP5217806B2 - Heating condition determining device, heating condition determining method and program - Google Patents

Description

  The present invention relates to an apparatus, a method and a program for determining a heating condition of a heating object when the heating object is heated in a heating furnace according to a target temperature profile, and a temperature profile of the heating object is predicted from the heating condition. More particularly, the present invention relates to a technique suitable for determining a heating condition of a reflow soldering apparatus for soldering an electronic component to a substrate.

  The reflow soldering device is an electronic device that is temporarily fixed with solder such as cream solder on a substrate such as a printed circuit board according to various heating methods such as heat radiation, hot air heating, steam heating, and heat transfer heating. It is an apparatus for joining and fixing parts by heating and melting the cream solder in a heating furnace.

  In the temperature profile for performing this reflow soldering, generally, the board is first soldered for the reason that the board and electronic components mounted on the board are heated suddenly to avoid thermal damage or poor soldering. Preheat at a temperature below the melting point, then heat uniformly to maintain the temperature of the substrate for a certain period of time so that the flux components in the cream solder function sufficiently, and finally the substrate is above the temperature at which the solder melts and the substrate In addition, the main heating is performed within a temperature range that does not exceed the heat resistance limit temperature of the electronic component.

  In such a temperature profile, instead of tin-lead solder with a low melting point, it is preferable for environmental protection, but lead-free solder with a high melting point has been used, so the heating control of the substrate can be managed with high accuracy in a narrow temperature range. It is required to do. However, the substrate has various materials and plate thicknesses, and the multilayer substrate has different heat capacities depending on the number of layers, etc. Also in electronic components, QFP (Quad Flat Package), electrolytic capacitors, etc. It is not easy to determine the heating conditions so as to follow the target temperature profile because the heat capacity and the like differ depending on the type and size of the parts.

  Conventionally, a temperature sensor is attached to the board, and a skilled engineer relies on experience and intuition to determine the target temperature profile by changing the heating conditions and repeatedly measuring the temperature. In addition, since workers are limited and trial and error are required, it takes time to determine heating conditions, and the same work must be repeated for each type of substrate.

Therefore, for example, Patent Literature 1 and Patent Literature 2 disclose a technique using computer simulation, and a technique for setting a heating temperature by fuzzy inference as in Patent Document 3 is also proposed.
Japanese Patent Laid-Open No. 11-201647 JP 2002-232131 A No. 7-39482

  However, in each of the techniques disclosed in Patent Documents 1 and 2, a heating condition is input to a certain substrate, a temperature profile is predicted by computer simulation, and whether or not the obtained result satisfies the standard is determined. Therefore, it requires skills relating to computer simulation, the number of workers is limited, and the same operation must be repeated for each type of substrate.

  Further, as in Patent Document 3, in the technique of setting the heating temperature by fuzzy reasoning, the same operation must be repeated for each type of substrate, and the time for exposure to a certain temperature or higher is considered. Therefore, it cannot be assured that the time over the melting point of the solder is over the time necessary for obtaining good soldering. Furthermore, there is a problem with respect to quality such that it cannot be guaranteed that the time during which the part is exposed to a heat resistant reference temperature (for example, 230 ° C.) or more is within an allowable range.

  The present invention has been made in view of the above points, and is capable of efficiently determining a heating condition that satisfies a temperature management standard without requiring specialized knowledge and skills. Another object is to enable simultaneous determination of heating conditions for a plurality of types of substrates.

(1) The heating condition determining apparatus of the present invention is an apparatus that determines a heating condition of the heating furnace that heats an object to be heated by conveying the object in a plurality of heating zones of the heating furnace, and determines the heating condition. Designated by the input means based on the input means for designating the heating object, the heating object data, the heating furnace data, and the temperature profile management reference data previously registered in the database, respectively. Calculating means for calculating the heating condition of the heating furnace so that the temperature profile of the heated object is within the control standard, and the calculating means sets the target temperature of the heating object in the heating zone. and the target temperature calculation unit calculating, the so heated object becomes the target temperature, see contains a heating temperature calculation unit for calculating a heating temperature of the heating zone, the target temperature calculation unit And the heating temperature calculation unit respectively calculates the target temperature and the heating temperature according to a plurality of types of temperature profiles, and the calculation means calculates each heating temperature according to each type of the temperature profile. And a heating temperature synthesis unit for synthesizing the final heating temperature. The plurality of types are two types, and the first type of temperature profile rapidly raises the temperature and then takes time. Thus, the second type of temperature profile is a temperature profile that makes the temperature rise uniform.

  As the heating object, for example, a substrate on which electronic components are temporarily fixed with solder is preferable.

  The heating zone of the heating furnace preferably includes a preheating zone for performing preheating and a main heating zone (reflow zone) for performing main heating.

  For the designation of the heating object by the input means, for example, one type of substrate may be designated, or a plurality of types of substrates may be designated. When multiple types of substrates are specified, the heating conditions are determined so that all of the temperature profiles of the multiple types of substrates are within the control criteria. This heating condition is a mixed flow of multiple types of substrates. It becomes a heating condition that can be produced.

  In addition, by registering in advance in the database which surface of the substrate is to be subject to temperature prediction as the heating object data, the surface of the substrate can be arbitrarily designated.

  The input means determines the heating condition for which heating object, that is, the heating condition for which heating furnace is determined in addition to the designation of the heating object, that is, the designation of the heating furnace to be used and the heating. It is preferable to specify the management standard of the temperature profile used for determining the conditions, and it is preferable to specify the initial temperature before the object to be heated is heated in the heating furnace.

  As the data of the object to be heated, for example, data such as the type, material, specific heat, density, size, and thickness of the substrate or component that is the object to be heated is preferable. Further, it is preferable that the board data includes data of a surface to be subjected to temperature prediction and parts data to be subjected to temperature prediction on that surface. By registering such data in advance, when a board is specified, the heating conditions are determined so that all of the parts that should be subject to temperature prediction of the board are within the temperature profile management criteria. Is done.

  As the data of the heating furnace, for example, data such as the number of heating zones, the size of the zones, and heating characteristic values indicating the degree of heat transfer are preferable.

  As the data for the management standard of the temperature profile, for example, data such as a temperature range in a heating zone for preheating, a preheating time, a temperature range in a heating zone for performing main heating, a residence time, a soldering temperature, and a soldering required time are preferable. .

  It is preferable that the calculation means includes a conveyance speed calculation unit that calculates the conveyance speed of the heating object in the heating zone, and it is preferable to calculate the conveyance speed of the heating object as a heating condition. It may be calculated and input to the heating condition determining apparatus.

  It is preferable that the conveyance speed calculation unit calculates the conveyance speed of the heating object in the heating zone based on the reflow residence time, the cooling time, and the length of the main heating (reflow) zone.

  The target temperature calculation unit of the calculation means approximates that the temperature of the heating object increases linearly based on the upper or lower temperature of the management reference of the temperature profile, the initial temperature before heating, and the conveyance speed of the heating object. Thus, it is preferable to calculate the target temperature of the heating object in the heating zone. It is preferable that the target temperature is calculated for all the places to be subjected to temperature prediction for the designated heating object, and the minimum value or the maximum value thereof is adopted.

  It is preferable that the heating temperature calculation part of the calculation means calculates the heating temperature of the heating zone based on the initial temperature when the object to be heated is carried into the heating zone and the heating time in the heating zone. It is preferable that the heating temperature is calculated for all the locations to be subjected to temperature prediction for the specified heating object, and the minimum value or the maximum value is adopted.

  Rather than performing temperature prediction on the entire heating object, it is possible to reduce the amount of calculation processing by the calculation means by limiting it to any part of the heating object registered in the database in advance. Thus, the calculation speed and memory capacity of the CPU constituting the calculation means can be made relatively small.

  The heating conditions preferably include at least the heating temperature of the heating zone, and further include the conveyance speed of the object to be heated in the heating zone.

  The heating condition determined by the heating condition determination device may be set directly by communication or the like to the control device that controls the heating furnace, or the determined heating condition is displayed on a display unit or the like. Then, the user may set the displayed heating condition in the control device.

  If the temperature profile of the specified object to be heated does not fit within the management standard due to the performance of the furnace or the contents of the management standard, which part of the heating target does not fit into which standard of the management standard Is preferably displayed on a display unit or the like.

  According to the heating condition determination apparatus of the present invention, the temperature profile of the specified heating object is managed based on the data of the heating object registered in advance, the data of the heating furnace, and the data of the management standard of the temperature profile. The target temperature of the heating object in the heating zone is calculated so that it falls within the standard, and the heating temperature of the heating zone is calculated so that the temperature of the heating object becomes the target temperature. The heating temperature of the heating zone, that is, the heating conditions can be determined so as to fall within the range.

  In the heating temperature synthesizing unit, it is preferable that the synthesis ratio can be adjusted. At this time, it is preferable that the synthesized temperature profile can be displayed on the display unit or the like.

According to the heating condition determining apparatus of the present invention, the heating temperature can be calculated according to each type of temperature profile, and the final heating temperature can be calculated by synthesizing each type of temperature profile. Also, by allowing the composition ratio to be adjusted, if the temperature profile does not fit within the control criteria, the heating temperature of the heating zone, i.e., the heating, is adjusted so that the composition ratio is adjusted and within the control criteria. The condition can be corrected.

  The first type of temperature profile is preferably a temperature profile close to the upper limit of the management standard.

  The first type of temperature profile is effective in reducing variation in temperature, and the second type of temperature profile is effective in reducing thermal damage. In this embodiment, the characteristics of each temperature profile are effectively used. Can be used.

(2) In one embodiment of the heating condition determining apparatus of the present invention, the calculating means performs calculation of the heating conditions at the same time to a plurality of heating object designated by said input means, the temperature profile management criteria A common heating condition can be determined for some or all of the plurality of heating objects that fall within.

  According to this embodiment, when it is possible to determine common heating conditions that fall within the temperature profile management standard for all of the plurality of designated heating objects, all of the plurality of heating objects are determined according to the common heating conditions. If a common heating condition that falls within the temperature profile control criteria can be determined for a part, but not all, of a plurality of designated heating objects, the common heating Depending on the conditions, a part of the plurality of heating objects can be heated.

  Thereby, some or all of the plurality of heating objects can be efficiently heated without changing the heating conditions.

( 3 ) The heating condition determination method of the present invention is a method for determining the heating condition of the heating furnace in which the heating object is heated while being conveyed in a plurality of heating zones of the heating furnace. Based on the data stored in the database in which the data, the heating furnace data, and the temperature profile management standard data are registered in advance, the temperature profile of the designated heating object is within the management standard. And a calculation step for calculating a heating condition of the heating furnace, wherein the calculation step includes a target temperature calculation step for calculating a target temperature of the heating target in the heating zone, and the heating target is set to the target temperature. to, look including a heating temperature calculating a heating temperature of the heating zone, the target temperature calculation step and the heating temperature calculation step, a plurality of types of temperature The target temperature and the heating temperature are respectively calculated according to the profiles, and the calculation step is performed by combining the calculated heating temperatures according to the respective types of temperature profiles to obtain a final heating temperature. The method further includes a synthesis step, wherein the plurality of types are two types, and the temperature profile of the first type is a temperature profile in which the temperature is rapidly raised and then the temperature is made constant over time, This kind of temperature profile is a temperature profile that makes the temperature rise uniform.

  According to the heating condition determination method of the present invention, the temperature profile of the specified heating object is managed based on the data of the heating object registered in advance, the data of the heating furnace, and the data of the management standard of the temperature profile. The target temperature of the object to be heated in the heating zone is calculated so that it falls within the standard, and the heating temperature in the heating zone is calculated so that it reaches the target temperature. Conditions can be determined.

( 4 ) The program of the present invention is a program used in a method for determining heating conditions of the heating furnace in which the heating object is heated by being conveyed in a plurality of heating zones of the heating furnace. Based on the data stored in the database in which the data, the heating furnace data, and the temperature profile management standard data are registered in advance, the temperature profile of the designated heating object is within the management standard. A program for causing a computer to execute a procedure for calculating a heating condition of the heating furnace, wherein the calculating procedure includes a procedure for calculating a target temperature of a heating object in the heating zone, and the heating object is the target so that a temperature, see contains a procedure for calculating the heating temperature of the heating zones, the procedure for calculating the procedure and the heating temperature for calculating the target temperature The target temperature and the heating temperature are respectively calculated according to a plurality of types of temperature profiles, and the calculation procedure is performed by synthesizing the calculated heating temperatures according to the types of temperature profiles. And a step of synthesizing the heating temperature, wherein the plurality of types are two types, and the temperature profile of the first type rapidly raises the temperature and then makes the temperature constant over time. The second type temperature profile is a temperature profile that makes the temperature rise uniform.

  The program of the present invention may be recorded on a computer-readable recording medium such as a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, and a ROM.

  According to the program of the present invention, by causing the computer to execute the program, the heating object specified based on the data of the heating object registered in advance, the data of the heating furnace, and the data of the management reference of the temperature profile is specified. The target temperature of the object to be heated in the heating zone is calculated so that the temperature profile of the object falls within the control standard, and the heating temperature of the heating zone is calculated so that the target temperature is reached. The heating conditions can be determined so as to be within.

  According to the present invention, based on pre-registered heating object data, heating furnace data, and temperature profile management reference data, the specified heating object temperature profile falls within the management reference. Thus, the target temperature of the heating object in the heating zone is calculated, and further, the heating temperature of the heating zone is calculated so that the temperature of the heating object becomes the target temperature, so that it falls within the management standard of the temperature profile The heating conditions can be determined.

  Moreover, according to this invention, based on the designated heating conditions, the heating object data, and the heating furnace data, the temperature profile of the designated heating object can be calculated and predicted.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a reflow furnace as a heating furnace.

  The reflow furnace 1 includes a transport conveyor 4 that transports a substrate 2 on which electronic components are mounted to the inside of a housing 3, and six preheating zones Z1 to Z6 that perform preheating on the transported substrate 2. In addition, a single heating zone (reflow zone) Z7 for main heating above the temperature at which the solder melts and a cooling zone Z8 are provided.

  The preheating zones Z1 to Z6 and the main heating zone Z7 are respectively provided with a heat source 5 and a heating fan 6 such as an infrared heater and a hot air heater above and below, and the cooling zone Z8 is provided with a cooling fan 7 above. Yes.

  The substrate 2 is printed with cream solder, and electronic components are mounted thereon. The substrate 2 is sequentially transferred to the preheating zones Z1 to Z6, the main heating zone Z7, and the cooling zone Z8 by the conveyor 4. The electronic component is soldered to the substrate 2 by being conveyed.

  In the reflow furnace 1, heating conditions such as the heating temperatures of the zones Z <b> 1 to Z <b> 7, the conveyor speed of the conveyor 4, and the air volumes of the fans 6 and 7 are controlled by a control device (not shown). For such a control device, it is necessary to set the heating conditions so that the temperature control according to the management standard of the temperature profile can be performed.

  FIG. 2 is a schematic configuration diagram of a heating condition setting device 8 that determines a heating condition and sets it by communication or the like with respect to the control device that controls the reflow furnace 1 of FIG.

  The heating condition setting device 8 of this embodiment is configured by a personal computer. For example, a hard disk device of the heating condition setting device 8 includes data on a substrate and parts that are heating objects, reflow furnace data, and The temperature profile management reference data is registered in advance as a substrate / component database 9, a reflow furnace database 10, and a temperature profile management reference database 11.

  Further, the heating condition setting device 8 processes the data of each of the databases 9 to 11 to determine the heating conditions, and includes a CPU 12, a RAM 13 and a ROM 14 for controlling the whole. The CPU 12, the RAM 13 and the ROM 14 are provided. The calculation means for performing the required calculation for determining the heating condition is configured, and as will be described later, the speed of the conveyor, the target temperature of the heating object in each of the zones Z1 to Z7, and heating for setting the target temperature Calculation of temperature etc. is performed.

  The heating condition setting device 8 further includes an input device 15 such as a keyboard and a mouse for designating a heating object for obtaining the heating condition, and a liquid crystal display for displaying the obtained heating condition and a predicted temperature profile. The display device 16 is provided.

  The board / component database 9 stores board material data (specific heat / density), thickness, number of layers, component mounting position, etc., and the parts type, size, specific heat, etc. In addition, data such as density and temperature prediction target part (body or terminal) are stored.

  FIG. 3 is a diagram showing an example of a display screen of the display device 16 when registering data relating to the substrate. As shown in FIG. 3, the data relating to the board includes the form of the board, the board name, the material such as FR-4 and CEM-3, the length, the width, the plate thickness, the number of layers, and the component mounted on the A surface. There are the number of parts to be subjected to temperature prediction (A-side parts) and the number of parts to be subjected to temperature prediction (B-side parts) among the parts mounted on the B-side. Although not shown in FIG. 3, data such as specific heat, thermal conductivity, density, etc. are also registered for the substrate material.

  Further, as shown in FIG. 3, as the data relating to the substrate, QFP and SOP are used as a component list (A surface component list, B surface component list) for each component to be subjected to temperature prediction of the A surface and the B surface. There are a part type, a part name, a part position, a part such as a terminal and a body, and a terminal position.

  As described above, since the parts to be subjected to the temperature prediction are registered in advance as the substrate data, when the heating condition is determined by designating the substrate, it should be the object of the temperature prediction of the designated substrate. The heating conditions are determined so that all of the parts are within the management criteria of the temperature profile.

  Also, the substrates can be registered as a group as shown in the display screen example when registering a substrate group in FIG. 4, for example, one type of substrate can be registered as a substrate group, and a plurality of types can be registered. These boards can be combined and registered as a board group. Furthermore, the A surface and the B surface can be registered as target surfaces for substrate temperature prediction.

  Therefore, for example, if a plurality of types of substrates are registered as a substrate group, and the heating conditions are determined by specifying the substrate group, heating is performed so that all of the plurality of types of substrates are within the temperature profile management standard. Conditions will be determined. That is, it is possible to determine the heating conditions that allow mixed flow production of a plurality of types of substrates.

  Depending on the performance of the reflow furnace and the management standards, if it is not possible to determine the heating conditions that allow multiple types, for example, all three types of substrates, to fall within the management standards, as described later, the locations that do not fit within the management standards In addition, management criteria items that do not fit can be displayed on the display device 16.

  In this case, for example, if one of the three types of substrates does not fall within the management standard and the common heating condition can be determined so that the remaining two types of substrates fall within the management reference, this 2 Common heating conditions can be determined for the types of substrates, and for the one type of substrates, locations that do not fit within the management criteria and management criteria items can be displayed.

  As a result, only one type of substrate that does not fall within the management standard can be separated, and the two types of substrates can be heated by setting the determined common heating condition.

  When a plurality of heating objects are specified in this way, if at least some of the heating objects can determine common heating conditions that fall within the temperature profile management criteria, the heating conditions are determined. In addition, it is possible to display a heating object that does not fall within the management standard.

  FIG. 5 shows an example of a display screen when registering data related to a part, for example. Data related to parts includes data such as part name, type, and size. Although not shown in FIG. 5, specific heat, density, shape, and other data are registered for each type.

  The reflow furnace database 10 stores data of the number of heating zones and cooling zones, the size of the zones, the number of rotations of the fans, and the initial temperature, as shown in the display screen example at the time of registration in FIG. Although not shown in FIG. 6, the reflow furnace database 10 also stores data such as heating characteristic values indicating the heat transfer coefficient. Further, regarding the heating zone, a preheating zone and a main heating (reflow) zone are further distinguished.

  In the temperature profile management reference database 11, as shown in the display screen example when registering the temperature profile management reference in FIG. 7, the preheat temperature range, the preheat time, the reflow temperature range, the reflow residence allowable time, the temperature gradient, etc. Data is stored. Although not shown in FIG. 7, the temperature profile management reference database 11 also stores soldering temperature and time required for soldering.

  In the heating condition setting device 8 of this embodiment, the heating conditions are determined by the following procedure, and the heating conditions are set for the control device of the reflow furnace.

  FIG. 8 is a flowchart showing the overall flow of the heating condition setting procedure.

  First, the user operates the input device 15 based on the input screen shown in FIG. 9 displayed on the display device 16, for example, the target substrate group for which the heating condition is to be obtained, the reflow furnace to be used, and the temperature profile Management criteria (reference profile) are selected (step n101). The target board group may be a board group registered as one kind of board as shown in FIG. 4 described above, or may be a board group composed of a plurality of kinds of boards.

  Next, the wind speed (fan rotation speed) and initial temperature of the reflow furnace are set (step n102). Since the wind speed affects unpredictable component jumps and positional deviations, in this embodiment, manual setting is used, and as shown in FIG. 6 described above, it is set in three stages of L, M, and H. Yes. For example, room temperature is set as the initial temperature.

  Next, the heating condition setting device 8 calculates the speed of the conveyor 4 based on the above settings (step n103). The speed of the conveyor is calculated according to, for example, the following equation in consideration of the cooling time so as not to exceed the allowable residence time of the main heating zone of the reflow furnace.

Conveyor speed = length of main heating zone / (residence time-cooling time)
The cooling time may be a fixed value, for example, uniformly 10 s. Alternatively, the cooling temperature gradient may be determined by measurement or the like and then determined according to the following equation.

Cooling time (s) = {reflow peak temperature P (° C.) − Soldering temperature Q (° C.)} / Cooling temperature gradient (− ° C./s)
In this embodiment, the heating conditions of the preheating zone are determined by calculating two types of temperature profiles and combining them.

  One of the two types of temperature profiles is a flat profile that quickly rises up to the upper limit of the management standard and then aims for temperature uniformity over time. This flat profile aims at the limit of the upper limit temperature of the management standard.

  The other temperature profile aims at a uniform temperature rise and is called a mild profile.

  Hereinafter, the heating conditions for the flat profile in the preheating zone and the heating conditions for the mild profile in the preheating zone are calculated (steps n104 and 105).

  FIG. 10 is a flowchart showing a procedure for calculating the heating conditions of the flat profile of the preheating zone, and FIG. 11 is a diagram showing the flat profile of the preheating zone. In addition, in FIG. 11, it corresponds to the reflow furnace 1 of the above-mentioned FIG. 1, and on the time axis of the horizontal axis, the corresponding zones Z1 to Z8 are shown together, and a vertical thick solid line is the final The boundary between the preheating zone Z6 and the main heating (reflow) zone Z7 is shown.

  In FIG. 11, R is a reflow (main heating) temperature upper limit, P is a soldering peak temperature lower limit, Q is a soldering temperature, N is a preheating temperature upper limit, M is a preheating end temperature lower limit, L is a preheating temperature lower limit, t1 Is the allowable reflow residence time, t2 is the time required for soldering, and O is the heating start point. Moreover, broken line AB shows the temperature management reference | standard of the preheating part upper limit, and broken line CD shows the temperature management reference | standard of the preheating part minimum, respectively. Moreover, in FIG. 11, the example of the variation width | variety of the estimated temperature of the heating target object which estimates temperature with two temperature profiles is shown.

  First, it is calculated to which zone of the six preheating zones Z1 to Z6 the start point A of the management reference AB of the temperature profile at the upper limit of the preheating portion belongs. Specifically, based on the above-described conveyor speed and the length of each preheating zone Z1 to Z6, the calculation is performed by calculating backward from the end of preheating in the preheating zones Z1 to Z6. For example, when the upper limit of the preheating residence time is 2.5 min, the conveyor speed is 1.0 m / min, the length of each preheating zone Z1 to Z6 is 0.6 m, and the end of the preheating is the sixth preheating zone Z6, Since 2.5 / 1 / 0.6 = 1.83, the decimal point is rounded up and the starting point A belongs to the second preheating zone Z2.

  The target temperature at the end of the first preheating zone Z1 is obtained by approximating that the component temperature linearly increases from the initial temperature to the temperature L ° C. of the starting point A of the upper limit management reference AB. When the starting point A is after the third preheating zone Z3, the target temperature at the end of the preheating zone is similarly obtained up to the preheating zone immediately before the starting point A. The target temperature in this case is an upper limit that must not be exceeded.

  For the first preheating zone Z1, the heating temperature at which the temperature at the end of the first preheating zone Z1 becomes the target temperature is calculated from the initial temperature and the heating time for all the components for which the temperature is predicted. This is the heating temperature of the first preheating zone Z1. For example, when the target is three parts of a, b, and c, the heating temperature of a is 120 ° C, the heating temperature of b is 130 ° C, and the heating temperature of c is 110 ° C, the heating temperature is the minimum of these If the temperature is 110 ° C., all parts are below the target temperature.

  When calculating the heating temperature, formulate in advance how much temperature the target component of temperature prediction will cause from the heat capacity and positional relationship (mounting surface and distance) of other nearby components. By registering in the database, the temperature of the target part can be predicted more accurately.

  When the starting point A is after the third preheating zone Z3, the heating temperature is similarly obtained up to the preheating zone immediately before the starting point A. For the second and subsequent preheating zones Z2, the temperature at the end of the immediately preceding preheating zone is set as the initial temperature.

  For the preheating zone including the start point A, the heating temperature is calculated so that the temperature at the end of the zone passing the start point A becomes the target temperature for all parts that should be the target of temperature prediction. Let it be the heating temperature. However, when the temperature exceeds N ° C. at the end of the zone, the heating temperature at which the target temperature N ° C. is reached at the end of the zone is calculated, and the lowest one is set as the heating temperature.

  Thereafter, up to the preheating end zone, the heating temperature at which the upper limit of the preheating temperature is N ° C. is calculated at the end of the zone for all components whose temperature is to be predicted, and the lowest one is set as the heating temperature.

  The above procedure is shown in the flowchart of FIG. 10 described above, and calculates the preheating zone n to which the start point A of the upper limit management standard AB belongs (step n201), and at the end of each zone up to the preheating zone n The target temperature is approximated and set by a straight line passing through the heating start point O and the start point A of the upper limit management reference AB (step n202), and preheating is performed so that all the temperature prediction target locations become the target temperature. The heating temperature of each zone up to zone n-1 is calculated, and the minimum value among them is adopted (step n203).

  Next, it is determined whether or not the target temperature Tn at the end of the preheating zone n is equal to or lower than the upper limit N ° C of the preheating temperature (step n204). The heating temperature of the preheating zone n is calculated so as to be Tn, and the minimum value is adopted (step n206). If it is not less than N ° C. in step n204, the target temperature Tn is set to N ° C. and the process proceeds to step n205 (step n208).

  Thereafter, the target temperature at the end of each zone from the preheating zone n + 1 to the end of preheating is set to N ° C. (step n206), and heating of each zone is performed so that the target temperature is N ° C. for all temperature prediction target portions. The temperature is calculated, the minimum value is adopted (step n207), and the process ends.

FIG. 12 is a flowchart showing a procedure for calculating the heating condition of the mild profile in the preheating zone, and FIG. 13 is a diagram showing the mild profile in the preheating zone.
The target temperature at the end of the preheating zone is set to N ° C., the upper limit of the preheating temperature (step n301).

  The target temperature at the end of each preheating zone is set by approximating that the component temperature increases linearly from the initial temperature (step n302). For example, when the preheating end is the sixth preheating zone Z6, the initial temperature is 25 ° C., and N = 180 ° C., the target temperature at the end of the first preheating zone Z1 is 25+ (180−25) × 1/6 = 50. 8 ° C. The target temperature in this case is also an upper limit that must not be exceeded.

  As with the flat profile setting procedure for preheating, the heating temperature at which the temperature at the end of each preheating zone becomes the target temperature is calculated from the initial temperature and heating time for all parts to be temperature predicted. A thing is made into the heating temperature of each preheating zone (step n303).

  As another embodiment, an allowable range (especially an upper limit) of the temperature increase gradient is provided, and when the temperature increase gradient to the target temperature is not within the allowable range, the zone ends when the temperature gradient is set to the upper limit value. The temperature reached sometimes may be set as a new target temperature.

  Next, the heating conditions of the main heating zone are calculated.

  The calculation of the heating conditions for the main heating zone differs depending on whether the main heating zone is one zone or a plurality of zones. In the case of a plurality of zones, two types of profiles, a flat profile and a mild profile, are formed as in preheating. However, it is possible to determine by combining at an arbitrary ratio.

  First, the case where the heating zone is one zone will be described based on the flowchart of FIG. 14 and the temperature profile of FIG. 11 described above.

  In FIG. 11, the trapezoidal thick solid line EF after preheating indicates the temperature management standard at the upper limit of the reflow part, and the thick triangular solid line GH indicates the temperature management standard at the lower limit of the reflow part. ing.

  First, the target temperature at the end of reflow (main heating zone) is set to the soldering peak temperature lower limit P ° C. (step n401), and the heating temperature at which the target temperature P ° C. is obtained for all the soldered portions, The largest one is set as the heating temperature (step n402). For example, when the target is three parts a, b, and c, the heating temperature of a is 240 ° C., the heating temperature of b is 250 ° C., and the heating temperature of C is 230 ° C., the heating temperature is the maximum of these If it is 250 degreeC of this, all the soldering parts will become P degreeC or more.

  When there is a portion that does not satisfy the required soldering time t2 (step n403), the heating temperature is increased by 1 ° C., for example, and the portion with the shortest soldering time is recalculated (steps n404 and 405). The temperature is finished as the heating temperature.

  Next, the case where the main heating zone is a plurality of zones will be described. In this case, the flat profile and the mild profile are synthesized as in the preheating.

  First, the procedure for calculating the heating conditions of the flat profile when there are a plurality of heating zones will be described based on the flowchart of FIG. 15 and the temperature profile of FIG. FIG. 16 shows an example in which the main heating zone has two zones.

  Based on the speed of the conveyor and the length of each zone, cooling starts at the end of the main heating zone, which zone of the main heating zone is the starting point E of the upper temperature control standard EF. Calculate as For example, when the allowable reflow residence time t1 is 50 s, the cooling time t3 is 10 s, the conveyor speed is 1.0 m / min, the length of each zone is 0.6 m, and the main heating zone is 2 zones, 2- (50-10 ) /60/1/0.6=0.88, the decimal point is rounded up and the starting point E is the first heating zone.

  When the starting point E is after the second zone of the main heating, it is approximated that the part temperature increases linearly from the reflow starting temperature to the temperature Q of the E point, and ends up to the zone immediately before the starting point E. Find the target temperature of the hour. The target temperature in this case is an upper limit that must not be exceeded.

  When the starting point E is the second and subsequent zones of the main heating, the heating temperature at which the temperature at the end of the zone becomes the target temperature is set to the initial temperature and the heating time for all the parts for which the temperature is predicted for each previous heating zone. From the above, the minimum one is set as the heating temperature.

  For the main heating zone including the starting point E, the heating temperature passing through the starting point E is calculated for all parts whose temperature is to be predicted, and the minimum one of them is set as the heating temperature. However, when the reflow temperature upper limit R ° C. is exceeded at the end of the zone, the heating temperature that becomes R ° C. at the end is calculated, and the minimum one of them is used as the heating temperature.

  Thereafter, up to the main heating end zone, for all the soldering parts for which the temperature profile is calculated, the heating temperature at which the soldering peak temperature lower limit P ° C is reached at the end of the zone is calculated, and the maximum one of them is used as the heating temperature. . For example, if the target is three parts a, b, and c, the heating temperature of a is 240 ° C, the heating temperature of b is 250 ° C, and the heating temperature of c is 230 ° C, the heating temperature is the maximum of these If it is 250 degreeC of this, all the soldering parts will become P degreeC or more.

  The above procedure is shown in the flowchart of FIG. 15 described above, and the main heating zone m to which the start point E of the upper limit temperature management reference EF belongs is calculated (step n501). Each zone end time target temperature is approximated and set by a straight line passing through the reflow start point and the start point E of the upper limit temperature management reference EF (step n502) so that the target temperature is set to the target temperature for all temperature prediction target portions. Then, the heating temperature of each zone up to the main heating zone m-1 is calculated, and the minimum value among them is adopted (step n503).

  Next, it is determined whether or not the target temperature Tm at the end of the heating zone m is equal to or lower than the reflow temperature upper limit R ° C. (step n504). The heating temperature of the main heating zone m is calculated so as to reach the temperature Tm, and the minimum value is adopted (step n505). If it is not less than R ° C in step n504, the target temperature is set to R ° C, and the process proceeds to step n505 (step n508).

  Thereafter, the target temperature at the end of each zone from the main heating zone m + 1 to the end of the main heating is set to P ° C. (step n506), and each zone is set so that the target temperature becomes P ° C. The heating temperature is calculated, the maximum value is adopted (step n507), and the process ends.

  It should be noted that up to the main heating zone including the starting point E and the subsequent main heating zones are different from each other, that is, the target is different for all parts to be temperature-predicted and all the soldered portions. In some cases, the temperature may be lower than the previous main heating zone, and the temperature of all parts does not increase uniformly as shown in FIG. 16. May go down. A typical example is a case where all the soldered portions have reached P ° C or higher in the process so far.

  Next, calculation of the heating conditions of the mild profile when there are a plurality of heating zones will be described based on the flowchart of FIG. 18 and the temperature profile of FIG.

  The target temperature at the end of the main heating is set to P ° C., which is the lower limit of the soldering peak temperature (step n601).

  A target temperature at the end of each main heating zone is set by approximating that the component temperature increases linearly from the reflow start temperature (step n602). For example, when the initial temperature is 180 ° C. and P = 245 ° C. in the second heating zone, the target temperature at the end of the first heating zone is 180+ (245−180) × 1/2 = 212.5 ° C. The target temperature in this case is a lower limit that should not be lower.

  Similar to the flat profile setting procedure in the main heating, the heating temperature at which the temperature at the end of each main heating zone becomes the target temperature is calculated for all the soldered portions, and the maximum one of them is calculated for each main heating zone. (Step n603).

  If there is a part that does not satisfy the required soldering time t2, the entire heating temperature is increased by 1 ° C. to recalculate the part with the shortest soldering time (steps n606 and 605), and the temperature at the time when the time t2 is satisfied is heated. The temperature is set (step n604).

  Next, synthesis of a flat profile and a mild profile will be described. A flat profile and a mild profile are synthesized at an arbitrary ratio to determine a final profile shape and heating conditions. In an arbitrary zone including the reflow zone, assuming that the heating temperature of the flat profile is T1, the heating temperature of the mild profile is T2, and the synthesis ratio is x: y, the final heating temperature T is obtained by the following equation.

T = (T1x + T2y) / (x + y)
Usually, x: y = 1: 1, and the average temperature of the heating temperature calculated with the flat profile and the heating temperature calculated with the mild profile is used as the final heating temperature. This ratio can be adjusted as described later.

  FIG. 20 is a diagram showing an example of a display screen for the set value of the heating condition calculated as described above.

  As heating conditions, the temperature of the upper and lower heaters and the conveyor speed in the heating zones 1 to 7 are displayed. In this embodiment, the rotational speeds of the upper and lower fans are manually set as described above.

  In this embodiment, in addition to the heating conditions, a predicted temperature profile is displayed for the specified board or component under the determined heating conditions. As described above, this temperature profile is a temperature profile when the synthesis ratio x: y = 1: 1. In FIG. 20, under the determined heating conditions, predicted temperature profiles for the three parts of the terminal of the component A and the body of the component B on the board Board1 and the terminal of the component C on the board Board2 are shown. It is displayed.

  A comparison result between the predicted temperature profile and the temperature range and time of the management reference is displayed in comparison, and a portion that deviates from the reference can be displayed in red, for example, to warn the user. In addition, the range of the management standard can be displayed on the temperature profile so that a portion that deviates from the standard can be clearly seen.

  When the predicted temperature profile is such that there is a portion that deviates from the management standard, x: y that is the above-described synthesis ratio is adjusted.

  Since the flat profile is suitable for reducing the temperature variation ΔT and the mild profile is suitable for reducing the amount of heat, that is, thermal damage, the composition ratio may be adjusted according to the purpose. Note that ΔT and the amount to be heated are in a trade-off relationship as shown in Table 1 below.

  When the synthesis ratio x: y is adjusted, the shape of the predicted temperature profile is adjusted, and the heating temperature T is also adjusted. This synthesis ratio x: y may be 1: 0 or 0: 1 and only one temperature profile may be used.

  If the desired temperature profile cannot be obtained only by adjusting the composition ratio of the flat profile and the mild profile, there is a method of synthesizing by changing the shape of the mild profile in the preheating zone.

  That is, as shown in FIG. 21, the zone for setting the target temperature N ° C. in the mild profile is shifted forward (to the left in the figure), for example, by one zone, and the remaining preheating zone is set in the same manner as the flat profile setting procedure. Then, when the flat profile and the shifted mild profile are combined, it is possible to reduce ΔT while suppressing the amount of heating. When the number of zones shifted forward is increased, a shape close to a flat profile is obtained.

  Here, referring again to the flowchart of FIG. 8 described above, after calculating the heating conditions of the flat profile and mild profile of the preheating zone in steps n104 and 105, the heating conditions of the main heating zone are further calculated in steps n106 and 107. Is calculated as described above, and the heating conditions are calculated by combining both profiles in step n108. It is determined whether or not the heating condition satisfies the management standard (step n109). If the heating condition is satisfied, the setting is terminated. If not, the composition ratio of the profile is adjusted as described above (step n). n110), the process ends when the management criteria are satisfied. If the management standard is not satisfied, the mild profile is shifted by one zone as described above (steps n111 and 112), and it is determined whether the temperature rise is slower than the flat profile (step n113). Returning to step n108, if it is not late, it is determined that the heating condition that satisfies the management standard cannot be set, and the substrate / part that does not satisfy the management standard is separated and reset (step n114).

  In the above-described embodiment, the heating condition is determined and the temperature profile of the specified component is predicted under the determined heating condition. However, by inputting an arbitrary heating condition and a target board or component to be predicted, It is possible to predict the temperature profile of the board or component under the input heating conditions. As in the case of determining the heating condition, the location where the temperature profile is predicted is not limited to the case where the same surface on the same substrate is targeted, but can be predicted for any surface of a plurality of types of substrates.

  The present invention is useful for reflow soldering of an electronic component to a substrate.

It is a figure which shows schematic structure of a reflow furnace. It is a block diagram of the heating condition setting device concerning the embodiment of the present invention. It is a figure which shows the example of a display screen at the time of registering the data regarding a board | substrate. It is a figure which shows the example of a display screen at the time of registering a board | substrate group. It is a figure which shows the example of a display screen at the time of registering the data regarding components. It is a figure which shows the example of a display screen at the time of registering the data regarding a reflow furnace. It is a figure which shows the example of a display screen in the case of registration of the management reference of a temperature profile. It is a flowchart which shows the whole flow of the setting procedure of heating conditions. It is a figure which shows the example of an input screen for setting heating conditions. It is a flowchart which shows the procedure of calculation of the heating conditions of the flat profile of a preheating zone. It is a figure which shows the flat profile of a preheating zone. It is a flowchart which shows the procedure of calculation of the heating conditions of the mild profile of a preheating zone. It is a figure which shows the mild profile of a preheating zone. It is a flowchart which shows the procedure of calculation of the heating conditions in case this heating zone is 1 zone. It is a flowchart which shows the procedure of calculation of the heating conditions of a flat profile in case this heating zone is a plurality of zones. It is a figure which shows the flat profile in case this heating zone is a multiple zone. It is a figure which shows the other flat profile in case this heating zone is a multiple zone. It is a flowchart which shows the procedure of calculation of the heating conditions of a mild profile in case this heating zone is a plurality of zones. It is a figure which shows the mild profile in case this heating zone is a multiple zone. It is a figure which shows the example of a display screen of the setting value of a heating condition, and the estimated temperature profile. It is a figure which shows the shape change of a mild profile.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reflow furnace 2 Board | substrate 4 Conveyor 5 Heat source 6 Heating fan 7 Cooling fan 8 Heating condition setting apparatus 9 Board | substrate / part database 10 Reflow furnace database 11 Temperature profile management reference database

Claims (4)

An apparatus for determining a heating condition of the heating furnace that heats an object to be heated by conveying the plurality of heating zones in the heating furnace.
Input means for designating a heating object for determining heating conditions;
Based on the heating object data, the heating furnace data, and the temperature profile management reference data registered in the database in advance, the temperature profile of the heating object designated by the input means is the management A calculation means for calculating the heating condition of the heating furnace so as to be within the standard,
The calculation means includes a target temperature calculation unit that calculates a target temperature of the heating object in the heating zone, and a heating temperature calculation unit that calculates the heating temperature of the heating zone so that the heating object reaches the target temperature. only including,
The target temperature calculation unit and the heating temperature calculation unit calculate the target temperature and the heating temperature according to a plurality of types of temperature profiles, respectively.
The calculation means further includes a heating temperature synthesis unit that combines the heating temperatures calculated according to the temperature profiles of the respective types to obtain a final heating temperature,
The plurality of types are two types, and the temperature profile of the first type is a temperature profile in which the temperature is rapidly raised and then the temperature is made constant over time, and the temperature profile of the second type is An apparatus for determining heating conditions, characterized in that the temperature profile makes the temperature rise uniform .   The calculating means can simultaneously calculate heating conditions for a plurality of heating objects specified by the input means, and can calculate common heating conditions for some or all of the plurality of heating objects. The heating condition determination apparatus according to claim 1. A method for determining a heating condition of the heating furnace that heats an object to be heated by conveying the inside of a plurality of heating zones of the heating furnace,
Based on the data of the database in which the data of the heating object, the heating furnace data, and the temperature profile management standard data are registered in advance, the temperature profile of the designated heating target is the management standard. A calculation step for calculating the heating conditions of the heating furnace so as to be within,
The calculation step includes a target temperature calculation step of calculating a target temperature of the heating object in the heating zone, and a heating temperature calculation step of calculating a heating temperature of the heating zone so that the heating object reaches the target temperature. only including,
The target temperature calculating step and the heating temperature calculating step calculate the target temperature and the heating temperature, respectively, according to a plurality of types of temperature profiles,
The calculating step further includes a heating temperature synthesis step of combining each heating temperature calculated according to each type of the temperature profile to obtain a final heating temperature,
The plurality of types are two types, and the temperature profile of the first type is a temperature profile in which the temperature is rapidly raised and then the temperature is made constant over time, and the temperature profile of the second type is A heating condition determination method characterized by a temperature profile that makes temperature rise uniform . A program used in a method for determining heating conditions of the heating furnace that heats an object to be heated by transporting it in a plurality of heating zones of the heating furnace,
Based on the data of the database in which the data of the heating object, the heating furnace data, and the temperature profile management standard data are registered in advance, the temperature profile of the designated heating target is the management standard. A program for causing a computer to execute a procedure for calculating the heating condition of the heating furnace so as to fit in
Procedure for the operation, the procedure for calculating the target temperature of the heating object in the heating zone, so that the heating object is the target temperature, see contains a procedure for calculating the heating temperature of the heating zone,
The procedure for calculating the target temperature and the procedure for calculating the heating temperature respectively calculate the target temperature and the heating temperature according to a plurality of types of temperature profiles,
The calculation step further includes a step of combining the heating temperatures calculated according to the temperature profiles of the respective types to synthesize the heating temperature as the final heating temperature,
The plurality of types are two types, and the temperature profile of the first type is a temperature profile in which the temperature is rapidly raised and then the temperature is made constant over time, and the temperature profile of the second type is A program characterized by a temperature profile that makes temperature rise uniform .

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