Temperature control method of test equipment and test equipment

Abstract

The invention relates to a temperature control method of test equipment and the test equipment. The temperature control method of the test equipment comprises the following steps: acquiring a current actual temperature Tc and a final target temperature Tt of a test cavity, wherein the current actual temperature Tc is smaller than the final target temperature Tt; based on the current actual temperature Tc and the final target temperature Tt, judging whether the test equipment meets a stage temperature rise condition or not; if the stage temperature rise condition is met, controlling the temperature of the test cavity to rise to the stage target temperature by taking Tc + delta Tp as the stage target temperature, and re-judging whether the stage temperature rise condition is met or not after preserving heat for a preset duration t at the stage target temperature; if not, controlling the temperature of the test cavity to rise to a final target temperature Tt; the stage temperature rising condition includes that delta T is not smaller than delta Tp, delta T is the absolute value of the difference value between the final target temperature Tt and the current actual temperature Tc, and delta Tp is the preset step temperature difference. According to the temperature control method provided by the invention, the problem of condensation in the temperature rise process of the test cavity can be solved.

Description

Technical Field

[0001] The present application relates to the field of temperature control testing technology, and in particular to a temperature control method for testing equipment and testing equipment. Background Art

[0002] Burn-in test is a non-destructive testing technology that applies a voltage higher than the normal operating voltage to the device under test (DUT) at a temperature higher than or lower than the normal temperature environment to screen out defective devices. At present, one technology for achieving high and low temperature test environments is chamber temperature control technology, which uses chillers and heaters as cold sources and heat sources respectively, and realizes chamber temperature control through heat and cold exchange. In the existing technology, the aging test machine uses chamber temperature control technology to control the temperature in the test chamber between -40℃ and 150℃. In actual tests, when the temperature in the test chamber runs for a long time in a low temperature environment of -40℃, the problem of frost and condensation in the test chamber caused by subsequent temperature increase has always been a pain point of the product. Although the frost and condensation locations are usually at the edge of the insufficient airflow, which has little effect on the test performance of the machine, the problem of frost and condensation in the test chamber due to temperature increase still poses the risk of damaging the device under test and causing an increase in condensed water.

[0003] In view of this, it is necessary to propose a new technical solution to overcome the shortcomings of the existing technology. Summary of the Invention

[0004] Based on this, the present application provides a temperature control method and test equipment for a test device, aiming to solve the problem of condensation occurring during the heating process of the test chamber.

[0005] To this end, the present application adopts the following technical solution: a temperature control method for a test device, wherein the test device has a test cavity, and the temperature control method comprises:

[0006] Acquire a current actual temperature Tc and a final target temperature Tt of the test chamber, wherein the current actual temperature Tc is less than the final target temperature Tt;

[0007] Determine whether the test equipment meets the stage heating condition based on the current actual temperature Tc and the final target temperature Tt;

[0008] If the stage heating condition is met, the temperature of the test chamber is controlled to rise to the stage target temperature with Tc+ΔTp as the stage target temperature, and is kept at the stage target temperature for a preset time t before re-evaluating whether the stage heating condition is met;

[0009] If the stage heating condition is not met, the temperature of the test chamber is controlled to rise to the final target temperature Tt;

[0010] Among them, the stepwise temperature increase conditions include: ΔT is not less than ΔTp, where ΔT is the absolute value of the difference between the final target temperature Tt and the current actual temperature Tc, and ΔTp is a preset stepwise temperature difference.

[0011] In one embodiment, the stepwise temperature increase conditions further include: the current actual temperature Tc is less than a preset temperature threshold Tp.

[0012] In one embodiment, the preset temperature threshold Tp is 45 to 55 °C.

[0013] In one embodiment, the preset stepwise temperature difference ΔTp is 15 to 30 °C.

[0014] In one embodiment, the preset duration t is 5 to 15 min.

[0015] In one embodiment, the stepwise temperature increase conditions include first-stage temperature increase conditions and second-stage temperature increase conditions; among them,

[0016] The first-stage temperature increase conditions include: Tc < Tp1 and ΔT ≥ ΔTp1;

[0017] The second-stage temperature increase conditions include: Tp1 < Tc < Tp2 and ΔT ≥ ΔTp2;

[0018] If the first-stage temperature increase conditions are satisfied, then using Tc + ΔTp1 as the stage target temperature, control the temperature of the test chamber to rise to this stage target temperature;

[0019] If the second-stage temperature increase conditions are satisfied, then using Tc + ΔTp2 as the stage target temperature, control the temperature of the test chamber to rise to this stage target temperature;

[0020] Among them, Tp1 is the first preset temperature threshold, Tp2 is the second preset temperature threshold, ΔTp1 is the preset first stepwise temperature difference, ΔTp2 is the preset second stepwise temperature difference, and Tp1 < Tp2, ΔTp1 < ΔTp2.

[0021] In one embodiment, the first preset temperature threshold Tp1 is -5 to 5 °C, the second preset temperature threshold Tp2 is 45 to 55 °C, the preset first stepwise temperature difference ΔTp1 is 15 to 25 °C, and the preset second stepwise temperature difference ΔTp2 is 20 to 30 °C.

[0022] This application also adopts the following technical solution: A testing device includes a testing module, a fan, and a temperature control system located in the test chamber. The fan is used to form a circulating temperature control air flow in the test chamber for the testing module to test the DUT at a set temperature. Among them, the temperature increase of the test chamber adopts the temperature control method described above.

[0023] In one embodiment, the temperature control system includes a cooling module and a heating module. The cooling module is configured to operate cooling during a temperature increase process, so that a local low temperature is formed in an area around the cooling module in the test chamber.

[0024] In one embodiment, a water receiving tray is provided below the refrigeration module, and the water receiving tray is used to receive liquid condensed or dripped on the refrigeration module.

[0025] The temperature control method of the test equipment provided in the present application determines whether the stage heating conditions are met. If the stage heating conditions are met, the temperature is raised in stages between the current actual temperature Tc and the final target temperature Tt and kept warm for a preset time to avoid the problem of frost and condensation in areas with uneven heat transfer due to excessive temperature difference caused by one increase. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 This is a schematic diagram of the internal structure of the test equipment for this application.

[0028] Figure 2 This is a wind speed cloud diagram at a cross section of the test chamber of the test equipment of this application.

[0029] Figure 3 This is a trend chart of temperature and dew point during the heating process of the test equipment for this application.

[0030] The reference numerals of the components are as follows:

[0031] 1. Fan; 2. Heater; 3. Temperature control sensor; 4. Air duct; 5. Diverter plate; 6. Evaporator; 7. Evaporator water tray; 8. Refrigerator; 9. Refrigerator water tray; 10. Test chamber. DETAILED DESCRIPTION

[0032] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0033] It should be noted that when a component is referred to as "fixed to" or "disposed on" another component, it can be directly on the other component or there can also be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in the description of this application are only for illustrative purposes and do not represent the only implementation.

[0034] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of this application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0035] In this application, unless otherwise clearly specified and limited, the first feature may be in direct contact with the second feature "on" or "under" the second feature, or the first feature and the second feature may be in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "beneath" and "underneath" the second feature may mean that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0036] Unless otherwise defined, all technical and scientific terms used in the description of this application have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the description of this application are only for the purpose of describing specific implementations and are not intended to limit this application. The term "and / or" used in the description of this application includes any and all combinations of one or more of the related listed items.

[0037] Please refer to Figures 1 to 3 As shown, the temperature control method of the test equipment provided by this application aims to solve the problem that when equipment such as an aging test machine and an aging test chamber operate at low temperature for a long time, condensation and dew formation occur in the areas with uneven heat transfer in the test chamber 10 during the heating process. During the heating process, when the temperature is in a relatively low range, the water vapor in the gas in the test chamber 10 condenses to form ice frost, which is condensation. When the temperature is in a slightly higher range, the water vapor in the gas in the test chamber 10 condenses to form small water droplets, which is dew formation. The problems of condensation and dew formation pose a risk of damaging the device under test (DUT); moreover, the increase in dew formation and the ablation of condensation frost result in an increase in condensed water, which also increases the problems in terms of condensed water discharge.

[0038] To solve the above problems, the present application provides a temperature control method for a test device. The test device has a test chamber 10, and the temperature control method includes:

[0039] Obtain the current actual temperature Tc and the final target temperature Tt of the test chamber 10, where the current actual temperature Tc is less than the final target temperature Tt;

[0040] Based on the current actual temperature Tc and the final target temperature Tt, determine whether the test device meets the staged heating condition;

[0041] If the staged heating condition is met, use Tc + ΔTp as the staged target temperature, control the temperature of the test chamber 10 to rise to this staged target temperature, and after maintaining the temperature at this staged target temperature for a preset duration t, re-determine whether the staged heating condition is met;

[0042] If the staged heating condition is not met, control the temperature of the test chamber 10 to rise to the final target temperature Tt;

[0043] Among them, the staged heating condition includes: ΔT is not less than ΔTp, where ΔT is the absolute value of the difference between the final target temperature Tt and the current actual temperature Tc, and ΔTp is a preset stepped temperature difference.

[0044] The temperature control method for the test device provided by the present application, by judging whether the staged heating condition is met, if the staged heating condition is met, then between the current actual temperature Tc and the final target temperature Tt, heat up in stages and maintain the temperature for a preset duration, avoiding the problem of frost condensation in the areas with uneven heat transfer caused by too large a temperature difference in a single lift. The situation that meets the above staged heating condition is that the absolute value of the difference between the final target temperature Tt and the current actual temperature Tc is relatively large; in this case, if the heating target is directly set to the final target temperature Tt during the heating process, it will cause a relatively large temperature difference between the areas with uneven heat transfer and the areas with uniform heat transfer, resulting in the precipitation of water vapor and the formation of frost and condensation. On the contrary, the situation that does not meet the above staged heating condition is that the absolute value of the difference between the final target temperature Tt and the current actual temperature Tc is not large, or even if this difference is large, but the increase in the temperature of the test chamber 10 is not sufficient to cause the precipitation of water vapor for the change in the dew point temperature. At this time, the temperature of the test chamber 10 can be directly controlled to rise to the final target temperature Tt.

[0045] Such as Figure 1As shown, in one embodiment, the test device includes a blower 1, a heater 2, a temperature control sensor 3, an air duct 4, a flow splitter 5, and a refrigeration module. The refrigeration module includes an evaporator 6 and a refrigerator 8. An evaporator water pan 7 is disposed below the evaporator 6, and a refrigerator water pan 9 is disposed below the refrigerator 8. The temperature rising process is as follows: The heater 2 operates to generate heat; the blower 1 blows air flow to flow through the heater 2 for heating and then is guided by the air duct 4. The flow splitter 5 rectifies and distributes the air flow to flow towards the test chamber 10 to control the temperature rising of the test chamber 10.

[0046] Please refer to Figure 3 As shown, when the temperature of a region is lower than the dew point temperature, water vapor will be condensed in that region, forming frost or dew condensation. The dew point temperature is not constant and is related to factors such as temperature and air pressure. To a certain extent, there is a positive correlation between the dew point temperature value and the ambient temperature where it is located. When the content of water molecules in the air remains unchanged and the air pressure remains unchanged, during the temperature drop process, the corresponding saturated water vapor pressure decreases, and the dew point temperature also decreases; on the contrary, during the temperature rise process, the corresponding saturated water vapor pressure increases, and the dew point temperature also increases. The internal flow field environment of the test chamber 10 is complex, and the chamber is a relatively closed environment. The dew point temperature is jointly affected by various factors such as temperature, pressure, and wind speed, and the change is more complex. The gaseous water molecules in the test chamber 10 will gather towards the low-temperature regions during the temperature rise process. When the temperature point of the low-temperature region is lower than the corresponding dew point temperature, the water molecules reach saturation in the low-temperature region and will precipitate to form frost or dew condensation. The low-temperature regions in the test chamber 10 are mainly the regions with insufficient flow rate and low flow velocity in the chamber. The low heat transfer efficiency of these regions results in a relatively low surface temperature recovery rate of the nearby structural components. Especially when the wind temperature changes violently, the untimely surface temperature recovery will cause the temperature difference between the surrounding components and other parts to continue to widen, causing a large amount of water vapor to converge towards this low-temperature position, thereby increasing the water vapor content in this part of the region and increasing the dew point value. Please refer to Figure 2 As shown, from Figure 2 the wind speed contour map of a cross-section of the test chamber 10 shown, it can be seen that the wind speeds at the positions marked A, B, C, and D in the figure are relatively small, and they are the regions where heat transfer is uneven and prone to frost and dew condensation. During the temperature rise process of the test chamber 10, due to uneven air flow, there are differences in heat transfer in different regions of the same cross-section. Since the air flow can be basically ensured to have the same air flow rate in each layer of the test chamber 10 after being adjusted by the flow splitter 5, taking a cross-section can represent the wind speed situation of the entire test chamber 10. In actual tests, the parts of the test chamber 10 close to the back and with more metal parts are extremely prone to dew condensation, that is, Figure 2 the position marked D in Figure 3 In the present application embodiment, during the temperature rise process, the temperature changes at these positions are mainly studied and analyzed. The temperature change conditions at these positions during the temperature rise process are measured by the temperature control sensor 3, and the temperature change diagram as shown in Figure 2Mark point A in the figure as Figure 3 the temperature measurement point 1 in it, mark point B as the temperature measurement point 2, mark point C as the temperature measurement point 3, and mark point D as the temperature measurement point 4. In Figure 3 among the 6 curves shown, from the stable stage, from top to bottom are the temperature curve of the temperature measurement point 4, the temperature curve of the temperature measurement point 1, the temperature curve of the temperature measurement point 2, the temperature curve of the temperature measurement point 3, the control temperature curve and the dew point value temperature curve. From Figure 3 the temperature curves of the 4 temperature measurement points shown, it can be seen that the temperature curves of the temperature measurement points 1-3 have the same trend and most of the curves are almost coincident, indicating that the wind speed conditions of the temperature measurement points 1-3 are roughly the same; the temperature curve of the temperature measurement point 4 is quite different from that of the temperature measurement points 1-3, indicating that the wind speed and heat exchange uniformity of the temperature measurement point 4 are quite different from those of other temperature measurement points. However, by adopting the stage heating-up scheme of the present application, the temperatures of the temperature measurement points 1 to 4 always remain higher than the dew point temperature value during the temperature recovery process. The stage heating-up scheme proposed by the present application utilizes the characteristic that the dew point temperature changes with temperature, and by controlling the stage heating-up, the areas with insufficient flow rate and low flow velocity can also have sufficient time for heat exchange to stably increase the temperature of this area and avoid the temperature of the components in this area being lower than the dew point value, so as to avoid the phenomenon of condensation and dew formation due to the precipitation of water vapor in this area.

[0047] The following uses several specific embodiments to illustrate the temperature control method of the test equipment of the present application.

[0048] Embodiment 1

[0049] In some embodiments, the stage heating-up conditions include: the current actual temperature Tc is less than the preset temperature threshold Tp, and ΔT is not less than ΔTp; where ΔT is the absolute value of the difference between the final target temperature Tt and the current actual temperature Tc, and ΔTp is the preset step temperature difference. The preset temperature threshold Tp is 45-55°C, the preset step temperature difference ΔTp is 15-30°C, and the preset holding duration t is 5-15 min.

[0050] As the temperature rises, the saturated water vapor pressure generally shows an exponential rising trend, while the dew point temperature generally shows a logarithmic rising trend. Therefore, when the temperature is higher than a certain preset temperature threshold, the rising rate of the dew point temperature is much lower than the rising rate of the temperature of each area in the test chamber 10, and conventional one-time direct heating can also ensure that there is no frost and dew in the test chamber 10; only stage temperature control is adopted when the temperature is lower than this preset temperature threshold. Through research and analysis, it is found that this preset temperature threshold is 45-55°C.

[0051] In the first embodiment, the preset temperature threshold Tp is taken as 50 °C, the preset stepped temperature difference ΔTp is 25 °C, and the preset heat preservation duration t is 10 min. That is, in the heating process, the current actual temperature Tc in the test chamber 10 and the final target temperature Tt are compared for the temperature difference multiple times. When Tc < 50 °C and Tt - Tc ≥ 25 °C, the temperature is controlled to rise by a lifting step of 25 °C to (Tc + 25) °C and stabilized for 10 min, and then the temperature difference is discriminated again; when Tc ≥ 50 °C or 0 °C ≤ |Tt - Tc| ≤ 25 °C, the temperature is controlled to rise linearly to Tt, and when the temperature difference between Tt and Tc is stabilized within 2 °C, it is determined that the heating is completed. Through actual tests, it is found that this embodiment performs well in the working condition of heating the temperature in the test chamber 10 above -10 °C. For the working condition where the temperature in the test chamber 10 is below -10 °C, there will still be a small amount of condensation phenomenon in some areas during the heating process.

[0052] Second Embodiment

[0053] In the second embodiment, the stage heating conditions are the same as those in the first embodiment, except for the values of the preset stepped temperature difference ΔTp and the preset heat preservation duration t. In the second embodiment, the preset stepped temperature difference ΔTp is 20 °C, and the preset heat preservation duration t is 6 min. That is, compared with the first embodiment, the lifting step value of the heating is smaller, and at the same time, the heat preservation duration is shorter. Specifically, in the heating process of the second embodiment, the current actual temperature Tc in the test chamber 10 and the final target temperature Tt are compared for the temperature difference multiple times. When Tc < 50 °C and Tt - Tc ≥ 20 °C, the temperature is controlled to rise by a lifting step of 20 °C to (Tc + 20) °C and stabilized for 6 min, and then the temperature difference is discriminated again; when Tc ≥ 50 °C or 0 °C ≤ |Tt - Tc| ≤ 20 °C, the temperature is controlled to rise linearly to Tt, and when the temperature difference between Tt and Tc is stabilized within 2 °C, it is determined that the heating is completed. Through actual tests, it is found that this embodiment meets the index of no frost or dew in the test area cavity above -40 °C. However, due to the small lifting step value of the heating, when the difference between the initial working condition temperature and the final target temperature Tt is too large, the temperature recovery efficiency is relatively low.

[0054] Third Embodiment

[0055] In some embodiments, the stepwise temperature increase conditions include a first-step temperature increase condition and a second-step temperature increase condition; wherein, the first-step temperature increase condition includes: Tc < Tp1 and ΔT ≥ ΔTp1; the second-step temperature increase condition includes: Tp1 < Tc < Tp2 and ΔT ≥ ΔTp2; if the first-step temperature increase condition is satisfied, then taking Tc + ΔTp1 as the step target temperature, controlling the temperature of the test chamber to rise to this step target temperature; if the second-step temperature increase condition is satisfied, then taking Tc + ΔTp2 as the step target temperature, controlling the temperature of the test chamber to rise to this step target temperature; wherein, Tp1 is the first preset temperature threshold, Tp2 is the second preset temperature threshold, ΔTp1 is the preset first-step temperature difference, ΔTp2 is the preset second-step temperature difference, and Tp1 < Tp2, ΔTp1 < ΔTp2. In some embodiments, the first preset temperature threshold Tp1 is -5 to 5 °C, the second preset temperature threshold Tp2 is 45 to 55 °C, the preset first-step temperature difference ΔTp1 is 15 to 25 °C, and the preset second-step temperature difference ΔTp2 is 20 to 30 °C. That is, by setting the first preset temperature threshold Tp1 and the second temperature threshold Tp2, the overall temperature increase stage is divided into from the initial operating temperature to Tp1, from Tp1 to Tp2, and from Tp2 to the final target temperature Tt. In the stage from the initial operating temperature to Tp1, the temperature is increased with a relatively small step temperature value, and in the stage from Tp1 to Tp2, the temperature is increased with a relatively large step temperature value, so as to balance anti-condensation and temperature increase efficiency.

[0056] Specifically, in the third embodiment, the temperature is controlled by staying for 6 minutes at a temperature increase step of 20 °C below 0 °C, staying for 6 minutes at a temperature increase step of 25 °C from 0 °C to 50 °C, and directly increasing the temperature to the final target temperature Tt in one step above 50 °C. That is, in the third embodiment, the first preset temperature threshold Tp1 is 0 °C, the second preset temperature threshold Tp2 is 50 °C, the preset first step temperature difference ΔTp1 is 20 °C, the preset second step temperature difference ΔTp2 is 25 °C, and the heat preservation duration t at each stage target temperature is 6 minutes. The specific temperature increase process of the third embodiment is to compare the current actual temperature Tc in the test chamber 10 with the final target temperature Tt multiple times. When Tc < 0 °C and Tt - Tc ≥ 20 °C, the temperature is controlled to increase to (Tc + 20) °C at a temperature increase step of 20 °C and stabilized for 6 minutes, and then the temperature difference is discriminated again; when 0 °C ≤ Tc ≤ 50 °C and Tt - Tc ≥ 25 °C, the temperature is controlled to increase to (Tc + 25) °C at a temperature increase step of 25 °C and stabilized for 6 minutes, and then the temperature difference is discriminated again; when 0 °C ≤ Tc ≤ 50 °C and 0 °C ≤ |Tt - Tc| ≤ 25 °C, or Tc ≥ 50 °C, the temperature is controlled to rise linearly to Tt, and when the temperature difference between Tt and Tc is stabilized within 2 °C, it is determined that the temperature recovery is completed. This solution not only meets the index of no frost and dew in the test chamber 10 during actual testing, but also can effectively improve the temperature increase efficiency by adjusting and selecting the best temperature increase step when the difference between the initial working condition temperature and the target temperature is too large.

[0057] It should be noted that the specific values in the above embodiments are only exemplary. Those skilled in the art can obtain solutions by selecting other values according to the temperature control method of staged temperature increase disclosed in the present application, which are also within the scope disclosed and protected by the present application.

[0058] Please refer to Figure 3 As shown, taking the BM020L aging test machine that has run at a low temperature of -40 °C for a long time and heated up to 150 °C as an example, the temperature is increased in a stepped manner in four temperature segments. The temperature is successively increased from -40 °C to -20 °C, 0 °C, 25 °C, and 50 °C and stays for 6 minutes respectively, and then the temperature can be directly increased to 150 °C. From Figure 3 It can be seen from the temperature increase curve graph that adopting this staged temperature increase scheme can ensure that the temperatures of temperature measurement points 1 to 4 always remain higher than the dew point temperature value during the temperature recovery process. After controlling the temperature at 50 °C for 6 minutes, the measured temperature and the dew point temperature gap is further widened, ensuring the reliability of the stepped temperature control. The solution of the present application solves the problem of frost and dew condensation in the temperature increase process of the test chamber 10 existing in the existing ultra-low temperature machine, and greatly improves the performance of the machine.

[0059] The present application also provides a test device, which includes a test chamber 10, a test module located in the test chamber 10, a fan 1, and a temperature control system. The fan 1 is used to form a circulating temperature-controlled air flow in the test chamber 10 for the test module to test a DUT (Device Under Test) at a set temperature. Among them, the temperature increase of the test chamber 10 adopts the above temperature control method. The temperature control system includes a refrigeration module and a heating module. The refrigeration module is configured to operate refrigeration during the temperature increase process so that a local low temperature is formed in the area around the refrigeration module in the test chamber. The refrigeration module includes at least one of a refrigerator 8 providing a cold source and an evaporator 6. By operating refrigeration during the temperature increase process, the water vapor in the test chamber 10 can be moved to the area around the refrigeration module in the chamber to achieve the purpose of reducing the dew point value of the above temperature measurement area. At the same time, the frost and dew condensation generated around the refrigeration module are also easily discharged through a drainage device. In this embodiment, a water receiving tray is provided below the refrigeration module. The water receiving tray includes, for example, an evaporator water receiving tray 7 and a refrigerator water receiving tray 9. The water receiving tray is used to receive the liquid condensed and dripped on the refrigeration module.

[0060] Currently, when a machine tool operating at ultra-low temperature for a long time enters the door-opening and temperature-returning stage after the test, the requirements for opening the door of the machine tool are that the temperature reaches 40 ± 5°C, and there is no frost or dew on the inner wall of the test chamber 10 and no water accumulation at the bottom of the chamber. For this reason, the existing solution is as follows: The heater receives an instruction to start running, maintains a high temperature of 65°C to exchange heat with the circulating air in the chamber, and the circulating air is used to return the temperature of each component in the chamber. During this process, the evaporator 6 does not work; when the ambient temperature in the chamber starts to rise, the frost on the outer wall of the evaporator 6 will inevitably melt due to the low-temperature industrial control. Therefore, an evaporator water receiving tray 7 is provided at the bottom of the evaporator 6; The 65°C circulating heat exchange runs for 2 hours to ensure that the temperature in the chamber rises to the target temperature and ensure that the liquid water in the evaporator water receiving tray 7 is converted into water vapor to meet the door-opening requirements. For this existing solution, due to the complex cavity structure, it is impossible to achieve absolute sealing. During the low-temperature operation process, a small amount of external air will enter due to the low pressure in the chamber. After multiple low-temperature operations, the water molecule content in the chamber accumulates and rises, increasing the frost on the surface of the evaporator 6, and the frost water during temperature return also accumulates continuously, making it difficult to meet the requirement of no water in the chamber, and the risk of frost and dew condensation in the test chamber 10 is high.

[0061] In the solution of this application, stage heating is adopted while heating and draining are coordinated. When a command to turn on the heater is received, the drainage device is turned on simultaneously. In the stage heating process of this application solution, the evaporator 6 operates to maintain a relatively low-temperature environment in a local area, causing the water vapor in the test chamber 10 to gather, condense, and drain at the evaporator 6, ensuring that the water vapor content in the rest of the chamber is always at a relatively low level. This enables the temperature in the relatively airtight chamber to uniformly reach the target value of 40 ± 5 °C in a short time, and also ensures that there is no frosting or dew condensation phenomenon in the test area during the process. The real-time drainage device can also save the time originally required for waiting for evaporation during the warm-up without water, further improving the efficiency of the machine. The door-opening warm-up solution provided by this application only takes 24 minutes to meet the door-opening requirements, with an 80% efficiency improvement compared to the existing solution.

[0062] From the description of the specific embodiments above, it can be seen that for the temperature control method and the test equipment provided by this application, by determining whether the stage heating condition is met, if the stage heating condition is met, then between the current actual temperature Tc and the final target temperature Tt, heating is carried out in stages and held for a preset duration, avoiding the problem of frosting and dew condensation in the areas with uneven heat transfer caused by too large a temperature difference in a single lift.

[0063] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as these combinations of technical features do not conflict, they should all be considered as within the scope described in this specification.

[0064] The above-described embodiments only represent several implementation manners of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of this application, several modifications and improvements can be made, and these all belong to the protection scope of this application. Therefore, the patent protection scope of this application should be subject to the appended claims.

Claims

1. A temperature control method for a test device, the test device having a test chamber, characterized in that, The temperature control method includes: Obtaining the current actual temperature Tc and the final target temperature Tt of the test chamber, where the current actual temperature Tc is less than the final target temperature Tt; Judging whether the test equipment meets the stage heating condition based on the current actual temperature Tc and the final target temperature Tt; If the stage heating condition is met, taking Tc + ΔTp as the stage target temperature, controlling the temperature of the test chamber to rise to this stage target temperature, and after maintaining the temperature at this stage target temperature for a preset duration t, re-judging whether the stage heating condition is met; If the stage heating condition is not met, controlling the temperature of the test chamber to rise to the final target temperature Tt; Wherein, the stage heating condition includes: ΔT is not less than ΔTp, ΔT is the absolute value of the difference between the final target temperature Tt and the current actual temperature Tc, and ΔTp is a preset step temperature difference.

2. The temperature control method of the test equipment according to claim 1, characterized in that, The stage heating condition further includes: the current actual temperature Tc is less than the preset temperature threshold Tp.

3. The temperature control method of the test device according to claim 2, characterized in that, The preset temperature threshold Tp is 45 - 55°C.

4. The temperature control method of the test device according to claim 1 or 2, characterized in that The preset step temperature difference ΔTp is 15 - 30°C.

5. The temperature control method of the test device according to claim 1 or 2, characterized in that, The preset duration t is 5 - 15 min.

6. The temperature control method of the test device according to claim 2, characterized in that, The stage heating condition includes a first-stage heating condition and a second-stage heating condition; wherein, The first-stage heating condition includes: Tc < Tp1 and ΔT ≥ ΔTp1; The second-stage heating condition includes: Tp1 < Tc < Tp2 and ΔT ≥ ΔTp2; If the first-stage heating condition is met, taking Tc + ΔTp1 as the stage target temperature, controlling the temperature of the test chamber to rise to this stage target temperature; If the second-stage heating condition is met, taking Tc + ΔTp2 as the stage target temperature, controlling the temperature of the test chamber to rise to this stage target temperature; Wherein, Tp1 is the first preset temperature threshold, Tp2 is the second preset temperature threshold, ΔTp1 is the preset first step temperature difference, ΔTp2 is the preset second step temperature difference, and Tp1 < Tp2, ΔTp1 < ΔTp2.

7. The temperature control method of the test device according to claim 6, characterized in that The first preset temperature threshold Tp1 is -5 - 5°C, the second preset temperature threshold Tp2 is 45 - 55°C, the preset first step temperature difference ΔTp1 is 15 - 25°C, and the preset second step temperature difference ΔTp2 is 20 - 30°C.

8. A test device, comprising a test module, a fan, and a temperature control system located in a test chamber, wherein the fan is configured to form a circulating temperature-controlled air flow in the test chamber for the test module to test a DUT at a set temperature, and is characterized in that, The temperature rise of the test chamber adopts the temperature control method as described in any one of claims 1 to 7.

9. The testing device according to claim 8, wherein, The temperature control system includes a refrigeration module and a heating module, and the refrigeration module is configured to operate refrigeration during the heating process so that the test chamber forms a local low temperature in the area around the refrigeration module.

10. The test device according to claim 9, characterized in that, A water receiving tray is provided below the refrigeration module, and the water receiving tray is used to receive the liquid condensed and dripped on the refrigeration module.

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