Technical Characteristics of Refrigeration and Temperature Control System of High and Low Temperature Test Chamber
High and low temperature test chamber is a kind of test equipment widely used in various industries, which is widely used to simulate various environmental conditions and test the durability, reliability and corrosion resistance of products. The technical characteristics of the high and low temperature test chamber are mainly reflected in its refrigeration system and temperature control system.
First of all, the refrigeration system of the high and low temperature test chamber has a high refrigeration capacity and refrigeration speed. During the temperature control process, a refrigeration system is needed to quickly reduce the temperature inside the test chamber. At present, the mainstream refrigeration system mainly has two kinds of compression refrigeration system and refrigerant loop circulation system. Among them, the compression refrigeration system has a high refrigeration capacity and refrigeration speed, which can quickly reduce the temperature inside the test chamber to the set temperature, but also to ensure the stability of the temperature.
Secondly, the temperature control system of the high and low temperature test chamber has high accuracy and stability. The temperature control system is the core part of the whole test chamber, which realizes the accurate control and stability maintenance of the internal temperature of the test chamber through the adjustment and control of the refrigeration system and the heating system. The current mainstream temperature control system mainly includes PID control system and intelligent control system. Among them, the PID control system has the characteristics of high precision and high stability, which can realize the accurate control of the temperature inside the test chamber, and is suitable for the test environment with high requirements for temperature control accuracy. The intelligent control system has the characteristics of more intelligent, and can realize the automatic control and adjustment of the internal temperature of the test chamber through self-learning algorithm and big data analysis technology, which is suitable for the occasions with relatively broad test environment requirements.
In summary, the technical characteristics of the high and low temperature test chamber are mainly reflected in its refrigeration system and temperature control system. The compression refrigeration system and PID control system have the characteristics of high cooling capacity, high cooling speed, high temperature control accuracy and high stability, which are suitable for the test environment requiring high temperature control accuracy and stability. In the future, with the development of artificial intelligence and Internet of Things technology, the control system of high and low temperature test chamber will continue to develop and improve in the direction of intelligence, automation and remote control, so as to better meet market demand.
How to Change the Refrigerant Oil of Thermal Shock Test Chamber?
Thermal shock test chamber is a necessary test equipment for metal, plastic, rubber, electronics and other material industries, used to test material structure or composite materials, in an instant under the continuous environment of extremely high temperature and extremely low temperature to endure the degree of chemical changes or physical damage caused by thermal expansion and contraction of the sample in the shortest time. Thermal shock test chamberr meets the test method: GB/T2423.1.2, GB/T10592-2008, GJB150.3 thermal shock test.
In thermal shock test chamber, if the compressor is semi-closed piston compressor in operation for 500 hours, it is necessary to observe the oil temperature and oil pressure changes of the frozen oil, and if the frozen oil is discolored, it must be replaced. After the initial operation of the compressor unit for 2000 hours, the cumulative operation of three years or the operation time of more than 10,000 to 12,000 hours should be maintained within a time limit and the chilled oil should be replaced.
The refrigerated oil replacement of the semi-closed piston compressor in thermal shock test chamber can be performed according to the following steps:
1, Close high pressure exhaust and low pressure suction stop valve of thermal shock test chamber, and then screw down the oil plug, the oil plug is generally in the bottom of the crankcase, and then put the frozen oil clean and clean the filter.
2, Use the low-pressure impact gas valve needle to blow nitrogen into the oil port and then use the pressure to discharge the residual oil in the body, install a clean filter and tighten the oil plug.
3. Connect the low pressure tube filled with fluorine gauge to the low pressure process valve needle with a vacuum pump to pump the crankcase into negative pressure, and then remove the other fluorine tube separately, put one end into the chilled oil, and put the other end on the valve needle of the low pressure suction of the oil pump. The chilled oil is sucked into the crankcase due to the negative pressure, and add it to the position slightly higher than the lower limit of the oil mirror line.
4. After injection, tighten the process column or remove the fluorine filling tube, and then connect the fluorine pressure gauge to vacuum the compressor.
5. After vacuuming, it is necessary to open the high and low pressure stop valve of the compressor to check whether the refrigerant has leaked.
6, Open thermal shock test chamber unit to check the lubrication of the compressor and the oil level of the oil mirror, the oil level can not be less than a quarter of the mirror.
The above is how to replace the refrigerant oil of the semi-closed piston compressor in thermal shock test chamber. Because the refrigerant oil has hygroscope, the replacement process needs to reduce the air entering the system and the oil storage container. If the cold aging oil is injected too much, there is the risk of liquid shock.
What are the Types of PCB Environmental Tests?
High acceleration test:
Accelerated tests include high accelerated life test (HALT) and High accelerated Stress screening (HASS). These tests assess the reliability of products in controlled environments, including high temperature, high humidity, and vibration/shock tests when the equipment is powered on. The goal is to simulate the conditions that could lead to the imminent failure of a new product. During testing, the product is monitored in a simulated environment. Environmental testing of electronic products usually involves testing in a small environmental chamber.
Humidity and corrosion:
Many PCBS will be deployed in wet environments, so a common test for PCB reliability is a water absorption test. In this type of test, the PCB is weighed before and after being placed in a humidity controlled environmental chamber. Any water adsorbent on the board will increase the weight of the board, and any significant change in weight will result in disqualification.
When performing these tests during operation, exposed conductors should not be corroded in a humid environment. Copper oxidizes easily when it reaches a certain potential, which is why exposed copper is often plated with an antioxidant alloy. Some examples include ENIG, ENIPIG, HASL, nickel gold, and nickel.
Thermal shock and circulation:
Heat testing is usually performed separately from humidity testing. These tests include repeatedly changing the board temperature and checking how thermal expansion/contraction affects reliability. In thermal shock testing, the circuit board uses a two-chamber system to quickly move between two temperature extremes. The low temperature is usually below the freezing point, and the high temperature is usually higher than the glass transition temperature of the substrate (above ~130 ° C). The thermal cycle is carried out using a single chamber, with the temperature changing from one extreme to the other at a rate of 10°C per minute.
In both tests, the board expands or contracts as the board temperature changes. During the expansion process, conductors and solder joints are subjected to high stress, which speeds up the service life of the product and enables the identification of mechanical failure points.
Introduction and Comparison of Thermocouple Temperature Sensing Lines
Instructions:
The background principle of thermocouple is "seebeck effect", also known as the thermoelectric effect, the phenomenon is that when two different metal endpoints are connected to form a closed loop, and if there is a temperature difference between the two endpoints, then there will be current generated between the loops, and the higher temperature contact in the loop is called "hot junction". This point is usually placed at the temperature measurement; The lower end of the temperature is called "cold junction", that is, the output end of the thermocouple, whose output signal is: DC voltage is converted into a digital signal through the A/D converter and converted into the actual temperature value through the softwares algorithm.
Various electric heating couples and their range of use(ASTM E 230 T/C):
type E
type J
type K
-100℃ to 1000℃±0.5℃
0℃ to 760℃±0.1℃
0℃ to 1370℃±0.7℃
Brown (skin color)+ purple - red
Brown (skin color)+ white - red
Brown (skin color)+ yellow - red
JIS,ANSI(ASTM) thermoelectric coupling appearance identification:
Thermoelectric coupling
JIS
ANSI(ASTM)
Rind
Positive end
Negative end
Rind
Positive end
Negative end
B type
Grayish
Red
white
Grayish
Grayish
Red
R,S type
Brown
Red
white
Green
Brown
Red
K,W,V type
Green
Red
white
Yellow
Yellow
Red
E type
Purple
Red
white
Purple
Purple
Red
J type
Yellow
Red
white
Brown
white
Red
T type
Tawny
Red
white
Green
Green
Red
Note:
1.ASTM, ANSI: American standard
2.JIS: Japanese standard
High and Low Temperature Test Standard for PC Plastic Material
First, high temperature test
After being placed at 80±2°C for 4 hours and at normal temperature for 2 hours, the dimensions, insulation resistance, voltage resistance, key function, and loop resistance should meet normal requirements, and the appearance should not be deformed, warped, or degumming. Key bumps collapsing at high temperatures and reduced pressing force are not evaluated.
Second, low temperature test
After being placed at -30±2℃ for 4 hours and at normal temperature for 2 hours, the dimensions, insulation resistance, voltage resistance, key function, and loop resistance should meet normal requirements, and the appearance should not be deformed, warped, or degumming.
Third, temperature cycling test
After being placed in 70±2℃ for 30 minutes, remove at room temperature for 5 minutes; then after being placed in -20±2℃ for 30 minutes, remove at room temperature for 5 minutes. After such 5 cycles, the dimensions, insulation resistance, voltage resistance, key function, and loop resistance should meet normal requirements, and the appearance should not be deformed, warped, or degumming. Key bumps collapsing at high temperatures and reduced pressing force are not evaluated.
Fourth, heat resistance
After being placed in an environment with a temperature of 40±2℃ and a relative humidity of 93±2%RH for 48 hours, the dimensions, insulation resistance, voltage resistance, key function, and loop resistance should meet normal requirements, and the appearance should not be deformed, warped, or degumming. Key bumps collapsing at high temperatures and reduced pressing force are not evaluated.
Test Method and Standard for High and Low Temperature Environment of Industrial Tablet Computer
In many industrial control scenarios, high environmental adaptability of industrial control tablets, industrial control machines, and touch screens, especially the adaptability of temperature, is extremely needed. This article introduces test method and standard for high and low temperature environment of industrial tablet computers, industrial control machines, etc.
1. High temperature operation test
(1) Test the basic functions of the whole machine to check the appearance of the normal structure first. According to MIL-STD-810G method 501.5 high temperature process, when the whole machine is in working state, put it into the test chamber at the normal position, set the temperature at 60℃, connect the adapter to run the local 1080P video for 24 hours, check once every 12 hours hours, and set the heating and cooling time for 2 hours.
(2) Judging criteria: During the high temperature working period, there should be no system crash, restart, blue screen and other unstable system operation; Video image, touch, sound, key function check; Check the basic functions of the machine after the test, functional failure should not appear; the display should not appear watermarks, white dots, white spots, etc..
2. Low temperature operation test
(1) Test the basic functions of the whole machine to check the appearance of the normal structure first. According to MIL-STD-810G method 501.5 high temperature process, when the whole machine is in working state, put it into the test chamber at the normal position, set the temperature at -20℃, connect the adapter to run the local 1080P video for 24 hours, check once every 12 hours hours, and set the heating and cooling time for 2 hours.
(2) Judging criteria: During the high temperature working period, there should be no system crash, restart, blue screen and other unstable system operation; Video image, touch, sound, key function check; Check the basic functions of the machine after the test, functional failure should not appear; the display should not appear watermarks, white dots, white spots, etc…
3. high temperature storage test
(1) Test the basic functions of the whole machine first. Set the temperature at 70°C±2°C for 48 hours in shutdown state, heating and cooling time for 2 hours, normal temperature recovery for 1 hour and then check the power and basic functions.
(2) Judging criteria: room temperature environment, research and maintenance engineers test the basic function of the machine without functional problems; Check the appearance and structure of the product.
4. low temperature storage test
(1) Test the basic functions of the whole machine first. Set the temperature at -30°C±2°C for 24 hours in shutdown state, heating and cooling time for 2 hours, normal temperature recovery for 2 hour and then check the power and basic functions.
(2) Judging criteria: room temperature environment, research and maintenance engineers test the basic function of the machine without functional problems; Check the appearance and structure of the product.
Composition and Application of Temperature and Humidity Regulating Chamber
Temperature and humidity regulating chamber is a device that controls the ambient temperature and humidity. It can provide a stable temperature and humidity environment to meet the requirements of a specific product or experiment. Temperature and humidity regulating chamber is usually composed of a control system, a heating system, a cooling system, a humidity control system and a circulation system.
In terms of working principle, temperature and humidity regulating chamber realizes temperature control through the control system to control the operation of the heating system and the refrigeration system. When the temperature is too low, the heating system starts and provides heat to raise the temperature; When the temperature is too high, the refrigeration system starts and absorbs heat to reduce the temperature. In this way, the temperature regulator can maintain a stable operating temperature.
The humidity control system of temperature and humidity regulating chamber is used to maintain a proper humidity level. When the humidity is too low, the humidity control system releases water vapor to increase the humidity; When the humidity is too high, the humidity control system absorbs the excess humidity to reduce the humidity. With precise humidity control, temperature regulators ensure that the ambient humidity is within the ideal range.
Temperature and humidity regulating chamber is widely used in practical applications. Taking the pharmaceutical industry as an example, some drugs have high requirements for temperature and humidity during processing and storage. If the ambient temperature and humidity are not effectively controlled, the quality and stability of these drugs will be affected. The temperature regulator can provide a stable working environment to ensure the quality and efficiency of the drug.
In the food industry, Temperature and humidity regulating chamber also plays an important role. For example, in the chocolate manufacturing process, the control of temperature and humidity directly affects the texture and taste of chocolate. The temperature regulator accurately controls temperature and humidity, ensuring that the chocolate production process meets standards and produces quality products.
Temperature and humidity regulating chamber is also widely used in electronic, chemical and other industries. In the electronics industry, temperature and humidity control is very important for the production and storage of electronic components. In the chemical industry, some chemical reactions have high requirements for temperature and humidity, which can provide a stable and safe working environment.
Introduction of Dust-free Oven
Dust-free oven, also called clean oven, is a special drying equipment that provides a high-temperature purification environment. The air inside the oven is closed and self-circulating, equipped with an enhanced air motor for forced air circulation exchange, and repeatedly filtered by a high-temperature and high-efficiency air purification filter, so that the drying oven studio is in a dust-free and clean state. The internal wall of dust-free oven studio is made of mirror stainless steel, and the external shell is made of stainless steel or cold-rolled steel plate. The temperature in the working room is automatically controlled by intelligent LED digital temperature controller, with PID regulating function, digital display time control function, and overtemperature alarm device, which is easy to operate and safe to use. These series of dust-free oven are suitable for drying electronic, pharmaceutical, optical, chemical and other enterprises and scientific research departments with clean requirements (the oven can be installed nitrogen port if there are special requirements).
Features of high-efficiency air filter dust-free oven:
1. Full week argon welding, high temperature resistant silica gel breaking, SUS304 # stainless steel electric heating manufacturer, micro dust produced by the guard machine itself;
2. High temperature resistance, under the premise that the clean level of the working site reaches class 1000, the laboratory can effectively filter the micro dust and reach the clean level of class 100;
3. Vertical type, reduce the site occupation area, with high efficiency.
Application of dust-free oven：
The dust-free oven is suitable for pre-treatment baking of silicon wafer, gallium arsenide, lithium niobate, glass and other materials before gluing, hard film baking after gluing and high temperature baking after developing in semiconductor manufacturing. It is also suitable for electronic liquid crystal display, LCD, CMOS, IS, medicine, laboratory and other production and scientific research departments; In addition, the dust-free industrial oven can be used for drying, heat treatment, aging and other high temperature tests of non-volatile and non-flammable and explosive items.
High and Low Temperature (& Humidity) Test Chamber (Battery Test Specifications)
Introduction of high and low temperature (& humidity) test chamber (battery test specifications):
High and low temperature (& humidity) test chamber (battery test specifications) mainly provides a constant temperature and high and low temperature alternating test environment for various secondary batteries and fuel cells and other new energy products in the research and development, production, inspection and other aspects of the test. For example: it can be used for lithium battery cells, modules and electric vehicle power; it can also used for lithium battery cells and modules related to energy storage industry.
Features of high and low temperature (& humidity) test chamber (battery test specifications):
Maintaining the advantages of high and low temperature (& humidity) test chamber-P series;
Adding pressure relief valve and observation window protection device to prevent sample explosion from causing injury to people;
Adding gas detection devices to detect flammable, explosive and harmful gases to provide against possible trouble;
Increasing automatic fire extinguishing device in case of fire to reduce losses;
Main parameters of high and low temperature (& humidity) test chamber (battery test specifications):
Studio size: 0.3m ~ 1.5m³(other sizes can be customized)
Temperature range: -40 ℃ ~ +150℃
Humidity range: 20% ~ 98%
Heating rate: 1℃ -5 ℃/min (full time)
Cooling rate: 1℃ -5 ℃/min (full time)
Temperature fluctuation: ±0.5
Temperature uniformity: 2℃
Temperature deviation: ±2℃
Humidity deviation: +2 ~ -3% (> 75%RH), ± 5% (≤ 75%RH)
ESS Rapid Temperature Change Stress Screening Machine
Environmental Stress Screening (ESS)
Stress screening is the use of acceleration techniques and environmental stress under the design strength limit, such as: burn in, temperature cycling, random vibration, power cycle... By accelerating the stress, the potential defects in the product emerge [potential parts material defects, design defects, process defects, process defects], and eliminate electronic or mechanical residual stress, as well as eliminate stray capacitors between multi-layer circuit boards, the early death stage of the product in the bath curve is removed and repaired in advance, so that the product through moderate screening, Save the normal period and decline period of the bathtub curve to avoid the product in the process of use, the test of environmental stress sometimes lead to failure, resulting in unnecessary losses. Although the use of ESS stress screening will increase the cost and time, for improving the product delivery yield and reduce the number of repairs, there is a significant effect, but for the total cost will be reduced. In addition, customer trust will also be improved, generally for electronic parts of the stress screening methods are pre-burning, temperature cycle, high temperature, low temperature, PCB printed circuit board stress screening method is temperature cycle, for the electronic cost of the stress screening is: Power pre-burning, temperature cycling, random vibration, in addition to the stress screen itself is a process stage, rather than a test, screening is 100% of the product procedure.
Product features of rapid temperature change stress screening machine:
1, It can set different stress screening temperature variation of 5°C/min, 10°C/min and 15°C/min.
2, It can perform rapid temperature change (stress screening), condensation test, high temperature and humidity, temperature and humidity cycle and other tests.
3, It meets the requirements of electronic equipment product stress screening test.
4, It can be switched between equal temperature and average temperature two test methods.
Specification requirements of rapid temperature change stress screening machine:
1, It can set a variety of stress screening (fast temperature variability) 5°C/min, 10°C/min and 15°C/min test conditions.
2, It meets the stress screening of electronic equipment products, lead free process, MIL-STD-2164, MIL-344A-4-16, MIL-2164A-19, NABMAT-9492, GJB-1032-90, GJB/Z34-5.1.6, IPC-9701 and other test requirement.
3, It can perform equal temperature and average temperature test mode.
4, It uses aluminum sheet to verify the load capacity of the machine (non-plastic load).
Semiconductor Limit Temperature Detection Scheme (Thermal Shock Test Chamber)
At present, many semiconductor devices must work in various harsh environments such as high and low temperatures for a long time, and the problem of high and low temperature failure is becoming more and more serious. In order to solve the problem of high and low temperature failure of discrete components, the electrical characteristics of devices and the variation of various parameters with temperature under low temperature environment are studied. Therefore, the setting and maintenance of high and low temperature environment is very important for semiconductor devices, which directly affects the feasibility of its normal operation and the accuracy of data. As a fast and accurate temperature control high and low temperature shock system, compared with the traditional temperature control test chamber, dragon temperature forcing system--Froilabo can test the temperature cycle of semiconductor devices or high and low temperature shock, and the temperature rising and dropping rate is very fast, such as temperature from -55℃ to +125℃ can be achieved in only 7s, and the temperature shock test can be carried out on the local area of the test sample without affecting other areas. And the temperature experiment can be carried out on the IC on the load board of test machine platform. Therefore, by using the Froilabo thermal shock system, it is perfectly possible to conduct temperature control tests on semiconductor discrete devices, investigate their ability to withstand extreme high and low temperatures, and the impact of alternating changes in extreme high temperature and extreme low temperature on the device.
Headquartered in Lyon, France, Froilabo has a history of more than 100 years and is a famous French manufacturer of temperature control equipment. Froilabo is a fast, precise temperature control of thermal shock system, its temperature control range is from -80℃ to 250℃. And its applicable fields cover defense industry, aviation industry, military industry, automation components, automotive parts, electronic and electrical instrumentation components, electrical products, plastic, chemical industry, food industry, BGA, PCB substrate, electronic chip IC, and semiconductor ceramic magnetic pharmaceutical industry. By using Froilabo thermal shock system, electronic components and materials can be thermally tested and characterized to improve their reliability, and the method is very simple to apply.
Clean Dust-free Oven
Clean oven is also known as dust-free oven, mainly using the air filter to purify the environment and avoid fine particles in the air into the chamber. The air inside the chamber is closed and self-circulating, which is repeatedly filtered by the 100-class high temperature and high efficiency air filter, so that the working room is in a dust-free state. The dust-free oven is suitable for pre-treatment baking of silicon wafer, gallium arsenide, lithium niobate, glass and other materials before gluing, hard film baking after gluing and high temperature baking after developing in semiconductor manufacturing. It is also suitable for electronic liquid crystal display, LCD, CMOS, IS, medicine, laboratory and other production and scientific research departments; In addition, the dust-free industrial oven can be used for drying, heat treatment, aging and other high temperature tests of non-volatile and non-flammable and explosive items.
Features of dust-free oven:
1. Structure: the structure of dust-free oven is reasonable, assembled by the box part, the electrical control cabinet, the electric heating and the air duct circulation system.
2, Sealing design: surrounded by argon welding, using high temperature silicone rubber dust-free sealing strip heat insulation, to ensure tightness and cleanliness;
3, External dust treatment: the external material is SPCC steel plate after powder spraying plastic, wear-resistant dust and slag;
4, High efficiency filter: HEPA filter structure clean room, 99.99% effective filtration, cleanliness reached grade 100;
5, Energy saving: insulation material for high-density fiber, heat preservation and energy saving;
6, Layered structure design: the height of the internal chamber layer can be adjusted and freely taken out;
7, Temperature control instrument: automatic control of temperature, constant temperature and time control, setting with over temperature automatic power outage and alarm circuit for reliable control and safe use.
8, Electrical accessories: all use the first-line brand, PID calculus temperature control system and overtemperature protection device, intelligent constant temperature, small temperature difference, suitable for different products of long and short baking.
Product parameters of dust-free oven:
1, Temperature range: from normal temperature to 250℃, constant temperature adjustable
2, External size: H1660*W770*D920mm; internal size: H900*W600*D600mm
3, Heating speed: from room temperature to 200℃ in about 30 minutes
4, Insulation performance: the outer wall temperature of the chamber does not exceed 45℃ (when the temperature inside the chamber reaches 200℃)
5, Temperature control accuracy: ±1℃
6, Temperature uniformity: ±3℃%
7, The use of power supply: 380V/50HZ (3 ∮ 5 wire)
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