116 results about "Bond strength" patented technology

The invention provides a fitting method for a vehicle-mounted curved surface display module, and the method comprises the steps: obtaining temperature data collected by a sensor, and generating an environment temperature sequence containing a timestamp and a temperature value; determining a fitting strength predicted value according to the environment temperature sequence; if the fitting strength predicted value exceeds a preset strength threshold value, determining a fitting parameter adjustment coefficient according to historical data; obtaining a fitting process parameter combination corresponding to the adjustment coefficient from a preset database, and generating an optimized fitting parameter set; inputting the optimized fitting parameter set into a control system, adjusting fitting equipment parameters, and monitoring to generate a fitting strength real-time sequence; and if the fluctuation amplitude of the fitting strength real-time sequence is smaller than a preset fluctuation threshold value, storing the fitting parameter set and the environment temperature sequence to a database.

The invention provides a preparation method of a high-temperature-resistant and anti-aging cable sheath material, which comprises the following steps: acquiring molecular chain distribution data of a polymer matrix and an inorganic filler, and establishing a bonding strength distribution diagram; obtaining regional non-uniform points, and optimizing filler distribution parameters; calculating a crosslinking temperature gradient model based on the compatibility improvement coefficient; predicting crosslinking density according to the model and correcting reaction parameters; evaluating the aging rate distribution and optimizing the dosage of the modifier. According to the method, filler dispersion is regulated and controlled through molecular-level bonding strength, a crosslinking temperature field is made to adapt to filler distribution, a formula is predicted and optimized in combination with aging behaviors, therefore, the structural uniformity and heat resistance of the material are remarkably improved, the service life of the material is remarkably prolonged, and the method solves the problems that in a traditional process, filler dispersion is not uniform, a crosslinking thermal field is mismatched, and aging evaluation is not accurate.

The invention discloses a wafer bonding strength testing method, which comprises the following steps of: cutting a bonded wafer into strip-shaped samples, adjusting a precise translation table to enable a laser head to be aligned with a bonding layer, scanning the bonding layer of the sample by using laser to obtain an inward initial crack, monitoring the position of the initial crack by using a microscope, and adjusting the precise translation table according to the position of the initial crack to test the bonding strength of the wafer. The method comprises the following steps: calibrating a crack to obtain a calibrated crack, adhering test pull rings to two sides of a sample with the calibrated crack, performing tension test on the pull rings to obtain a load-displacement curve of the sample, and calculating the bonding strength of the sample according to the load-displacement curve of the sample. According to the method, the submicron aligned preset cracks are processed through cutting and closed-loop calibration, and then the wafer bonding strength is quantitatively tested through a DCB method, so that the problem that the bonding strength of internal positions of wafers of a D2W bonding sample and a W2W bonding sample cannot be quantitatively tested is solved.

The invention relates to a preparation, regulation and control method of a thermoplastic elastomer encapsulating material in the technical field of new materials, which comprises the following steps: realizing an in-situ reaction process by controlling the concentration and reaction temperature of reactive functional groups in the encapsulating material according to an interface reaction rate constant and active group distribution density; if the reaction conversion rate reaches a preset value, a chemically bonded interface bonding layer is formed; monitoring the stress distribution state in the rubber coating layer by adopting a stress analysis algorithm, and when detecting that local stress concentration exceeds the yield strength of the material, dispersing a stress concentration area by adjusting the length of a flexible chain segment and the density of a rigid cross-linking point in a cross-linking network; and deformation data and a bonding strength change trend of the interface bonding layer in the temperature cycling process are obtained, if the bonding strength attenuation rate exceeds a preset threshold value, a dynamic cross-linking mechanism is activated, and the dynamic equilibrium state of interface bonding is maintained through fracture and recombination of a reversible covalent bond.

The invention discloses a method and a device for detecting the bonding strength of a coating, and belongs to the technical field of coating detection. The method for detecting the bonding strength of the coating comprises the following steps: respectively bombarding test areas of a plurality of samples to be detected by adopting first laser according to different control parameters; the method comprises the following steps: detecting the falling degree of a coating in a test area of each to-be-tested sample from a substrate, and judging whether the falling degree reaches a set degree or not; taking the control parameter of the first laser corresponding to the to-be-detected sample with the falling degree reaching the set degree as a critical control parameter; and controlling the first laser to bombard a coating area of a to-be-tested product with the same model as the to-be-tested sample according to the critical control parameter, and evaluating the coating bonding strength of the to-be-tested product according to the surface appearance of the to-be-tested product. The coating bonding strength can be measured without contact with the coating, matrix damage is avoided, detection precision and detection efficiency can be improved, manual intervention is reduced, cost is reduced, and environmental pollution is avoided.

Disclosed herein are embodiments of a method of forming a glass article having a glass cover sheet and a frame. The glass cover sheet includes a first major surface and a second major surface in which the second major surface is opposite the first major surface. The frame has a support surface. In the method, a pressure-sensitive adhesive tape is applied to a first region of the glass cover sheet or of the frame. A liquid adhesive is applied to a second region of the glass cover sheet or of the frame. Pressure is applied to the glass cover sheet and the frame to cause the pressure-sensitive adhesive to adhere the glass cover sheet to the frame at a first bond strength. The liquid adhesive is cured to adhere the glass cover sheet to the frame at a second bond strength that is greater than the first bond strength.

The invention discloses a wafer bonding strength characterization method, and relates to the field of wafer bonding tests.The method comprises the steps that a three-dimensional test model of interface fracture mechanics is built, the total deflection and shear modulus generated by a loading point in the test process are analyzed, and a compliance simulation calculation model corresponding to the three-dimensional test model is generated in combination with the crack length; optimizing the compliance simulation calculation model based on the actual model state of wafer bonding to obtain a compliance calculation model, and constructing an energy release rate calculation model in combination with the relationship between the compliance and the crack length; and loading the bonded sample by using a tensile machine, analyzing the peak load of the bonded sample according to the loading result, and obtaining the bonding strength of the bonded sample in combination with the compliance calculation model and the energy release rate calculation model. According to the method, the sample compliance calculation crack length obtained through experiments is substituted into the compliance calculation model and the energy release rate calculation model to obtain the bonding strength characterization result, the measurement method is simple, and the measurement result is more accurate.

The invention relates to a method for measuring wafer surface energy in hybrid bonding based on a chemically modified probe. The method comprises the following steps: carrying out surface pretreatment on an atomic force microscope probe and a wafer sample; constructing same functional group modification layers on the surfaces of the microscope probe and the wafer sample; the bending sensitivity, the elastic coefficient and the curvature radius of the probe are calibrated; acquiring a force-distance curve based on interaction between the probe covered by the functional group modification layer and the surface of the wafer sample, and calculating initial adhesion work based on the force-distance curve; and performing error correction on the initial adhesion work by using the surface energy measured by a contact angle method of a standard wafer sample, and establishing a quantitative mapping relation between the corrected adhesion work and the bonding strength. Compared with the prior art, the method has the advantages that the probe is subjected to functional group modification, the adhesive force of the surface of the sample is measured through the functionalized probe, and the surface energy of the wafer sample in mixed bonding is calculated in mixed bonding, so that the subsequent bonding strength of the sample is estimated.

A method for manufacturing a metal solid-to-metal solid bonded body, capable of improving a bond strength on a bonding face, and a composite member. A solid metal body containing a first component is brought into contact with a solid metal material composed of a compound, an alloy, or a non-equilibrium alloy, which contains both a second component and a third component having positive and negative heats of mixing respectively relative to the first component, and heated at a predetermined temperature for a predetermined time while applying a predetermined pressure to between the metal body and the metal material. Thereby, the first component and the third component are interdiffused with each other, and a liquid alloy containing the first component and the third component, which has been generated in a region where the first component and the third component have interdiffused with each other, is discharged.

The application provides a preparation method of a high-temperature-resistant and anti-aging cable sheath material, comprising the following steps: obtaining molecular chain distribution data of a polymer matrix and inorganic fillers, and establishing a bonding strength distribution graph; obtaining regional non-uniform points, and optimizing filler distribution parameters; calculating a crosslinking temperature gradient model based on a compatibility improvement coefficient; predicting crosslinking density and correcting reaction parameters according to the model; evaluating an aging rate distribution and optimizing a modifier dosage. The application controls filler dispersion through molecular-level bonding strength, makes the crosslinking temperature field self-adapt to the filler distribution, and optimizes the formula in combination with aging behavior prediction, so that the structural uniformity, heat resistance and service life of the material are significantly improved. The method solves the problems of uneven filler dispersion, mismatched crosslinking thermal field and inaccurate aging evaluation in the traditional process.

The utility model discloses a sample preparation tool for an adhesive strength sample, relates to the technical field of adhesive strength performance testing of adhesives, and can ensure the consistency of the sample after compression molding and improve the test accuracy and the sample preparation efficiency. The bonding strength sample preparation tool comprises an upper base, a lower base, a plurality of metal test blocks, a retainer and a plurality of rubber test pieces. A butt joint groove is formed in the upper base. And the lower base is detachably inserted into the butt joint groove. And a plurality of metal test blocks are uniformly arranged in the upper base and the lower base. And the retainer is arranged between the upper base and the lower base. Handles are arranged at two ends of the retainer. A plurality of test piece holes are uniformly formed in the retainer. And a plurality of rubber test pieces are arranged in the test piece holes one by one. The rubber test blocks are moved and bonded through the handle, so that the rubber test blocks can be accurately bonded with the metal test blocks in the upper base and the lower base, one-by-one manual operation of sample preparation personnel is avoided, and the probability of introducing dust, moisture and other impurities is reduced.

To improve bond strength between dissimilar materials through ultrasonic junction.SOLUTION: A tool for ultrasonic junction is given in which: the tool contacts with a surface of one member of an object to be joined where two members are overlapped to transfer supersonic vibration so that two members are joined. The tool includes: a body part which is columnarly extended; and a carbon layer which is formed on a contact surface contacting with the object to be joined in the body part. The object to be joined is obtained by overlapping an aluminum member made of aluminum material with a resin member, and the body part is contacted with the object to be joined from the surface of the aluminum member.SELECTED DRAWING: Figure 2

To provide a method for predicting the bonding strength of a resin / metal bonded body capable of accurately predicting the bonding strength between a resin and metal in the resin / metal bonded body in which the resin and the metal are bonded to each other.SOLUTION: The method for predicting the bonding strength of the resin / metal bonded body includes: a metal compound identification step S01 of identifying metal compounds present on a bonding surface of metal; an interface model formation step S02 of forming an interface model of the metal and a resin and of the metal compound and the resin; a bonding strength calculation step S03 of calculating the bonding strength between the metal and the resin and of the metal compound and the resin by computer simulation; a peak intensity ratio calculation step S04 of calculating a ratio ICmin / ICmax of a minimum peak intensity ICmin of a metal or a metal compound with the lowest bonding strength to a maximum peak intensity ICmax of a metal or a metal compound with the highest bonding strength; and a bonding strength evaluation step S05 of evaluating the bonding strength between the resin and the metal using the peak intensity ratio ICmin / ICmax as an evaluation criterion.SELECTED DRAWING: Figure 2

This invention discloses a method for measuring the bonding strength of a casting repair process, solving the problem in the prior art where the bonding strength of the casting repair process cannot be quantitatively obtained. It has the beneficial effect of accurately obtaining the bonding strength between the casting substrate and the repair layer, achieving quantitative strength measurement. The specific solution is as follows: A method for measuring the bonding strength of a casting repair process includes: preparing a specimen; cutting a groove in the specimen; cutting the specimen at the groove to obtain the substrate; repairing the cut specimen, with the repair layer covering the groove; breaking the repaired specimen and recording the maximum tensile force; and calculating the bonding strength between the substrate and the repair layer based on the maximum tensile force.

A bonding strength evaluation method may include preparing bonded wafers, separating the bonded wafers by applying a force to one surface of the bonded wafers in a direction perpendicular to the one surface of the bonded wafers, measuring at least one of the force applied to the one surface of the bonded wafers, a time when the force is applied, a separation distance between the bonded wafers, a length of an area where the bonded wafers are separated, and determining a bonding strength based on at least one of the force, the time during which the force is applied, the separation distance between the bonded wafers, and the length of the area where the bonded wafers are separated.

The present invention discloses a wafer bond strength characterization method, which relates to the field of wafer bond testing. The method comprises: building a three-dimensional test model of interface fracture mechanics, analyzing the total deflection and shear modulus generated by the loading point during the test, and generating a compliance simulation calculation model corresponding to the three-dimensional test model in combination with the crack length; optimizing the compliance simulation calculation model based on the actual model state of the wafer bonding to obtain a compliance calculation model, and constructing an energy release rate calculation model in combination with the relationship between compliance and crack length; loading the bonded sample using a tensile testing machine, analyzing the peak load of the bonded sample according to the loading result, and obtaining the bond strength of the bonded sample in combination with the compliance calculation model and the energy release rate calculation model. The present invention calculates the crack length using the sample compliance obtained through the experiment, and substitutes it into the compliance calculation model and the energy release rate calculation model to obtain the bond strength characterization result. The measurement method is simple and the measurement result is more accurate.

The invention discloses a preparation method of a single-component water-oil mixed type environment-friendly composite adhesive. The preparation method comprises the following steps: S1, a synergistic pretreatment stage; s2, a gradient polymerization stage; s3, an ultrasonic compounding stage; and S4, a low-temperature curing stage. Through the synergistic effect of the nanocellulose and the montmorillonite, modification of the green coupling agent and the graphene quantum dot-chitosan composite modified material, the problem that a traditional filler is prone to agglomeration is solved, the filler is evenly dispersed in the adhesive, the mechanical property of the adhesive is greatly improved, the gradient polymerization process has the advantages that the temperature is accurately controlled, and the mechanical property of the adhesive is greatly improved. According to the present invention, the monomer conversion rate is increased to more than 98%, the molecular weight distribution of the product is uniform, the stability of the bonding strength is ensured, the bonding strength can achieve 4.2 MPa, the strength retention rate can still achieve 92% in the temperature cycle test of-20-60 DEG C, the application reliability in different environments is ensured, and the high requirements on the adhesive performance in the fields of building, packaging and the like are met.

This invention relates to a high-temperature resistant adhesive suitable for bonding inert metals and its preparation method. It addresses the problems of low bond strength, poor bonding reliability under impact, and insufficient heat resistance in existing polyimide adhesives used for bonding titanium alloys or stainless steel. The high-temperature resistant adhesive is prepared from a polyimide precursor resin containing active metal complexes, a phthalate coupling agent, an inorganic filler, and solvent I. The preparation method includes: 1. Preparing the polyimide precursor resin containing active metal complexes; 2. Weighing; 3. Preparing the adhesive. This invention relates to a high-temperature resistant adhesive suitable for bonding inert metals and its preparation method.

The application provides a nondestructive testing method for the bonding strength of a coating of a semiconductor device shell, and belongs to the technical field of semiconductor device testing. The method solves the problem that the bonding strength of a coating and a substrate cannot be nondestructively evaluated in the prior art. The method comprises the following steps: arranging an acoustic wave coupling medium and an acoustic wave sensor on the surface of the coating, selecting at least three laser impact points, focusing a laser beam generated by a pulsed laser on the impact points, collecting a longitudinal wave signal after laser impact, reading a first echo signal peak voltage and a second echo signal peak voltage, calculating an acoustic pressure reflection coefficient R , performing laser impact on the same impact points for a second time at the same energy density, obtaining a reflection coefficient change amount R , calculating an average value R of the reflection coefficient change amounts R of the multiple impact points, and determining whether the bonding strength of the coating and the substrate meets a requirement according to the average value R avg When the average value R avg is greater than 0.05, it is determined that the bonding strength of the coating and the substrate does not meet the requirement, otherwise, the bonding strength of the coating and the substrate meets the requirement. The application can be used for the rapid and nondestructive evaluation of the bonding strength of a coating of a semiconductor device shell.

The invention provides an underwater adhesive as well as a preparation method and application thereof, and belongs to the technical field of adhesives. The adhesive comprises the following components in parts by weight: 1 part of polyethyleneimine; 1-5 parts of acrylic acid; 0.1 to 30 parts of an acrylate monomer; and 0.01 to 1.75 parts of a photoinitiator. The adhesive disclosed by the invention is cured under ultraviolet irradiation, the curing time can be shortened, and the adhesive has excellent adhesive strength.

The invention provides equipment for evaluating bonding strength, and belongs to the technical field of semiconductor production. Comprising a base; the carrier is mounted on the base and used for fixing a to-be-evaluated sample, and the to-be-evaluated sample comprises at least two objects which are combined together; the two stand columns are arranged on the base at a preset interval; the moving assembly is connected with the two stand columns respectively, and a cutter is installed on the moving assembly; the first driving mechanism is connected with the movement assembly, and the first driving mechanism is used for driving the movement assembly to drive the cutter to move in the vertical direction so as to be inserted into the to-be-evaluated sample or be far away from the to-be-evaluated sample; the displacement sensor is arranged on the movement assembly and used for detecting displacement information of the movement assembly; the force sensor is used for detecting stress information of the motion assembly; and the controller is used for acquiring the displacement information and the stress information, and evaluating the bonding strength of the to-be-evaluated sample according to the displacement information and the stress information. According to the technical scheme, the bonding strength can be accurately evaluated.

The invention belongs to the technical field of additive manufacturing and electronic circuit manufacturing, and particularly relates to a metal surface high-bonding-strength polymer additive manufacturing method which comprises the following steps: preparing a metal conductive layer on the surface of a pretreated insulating base material by utilizing an additive electronic manufacturing process; carrying out polymer solution in-situ printing and curing on the metal conductive layer to obtain a transition layer combined with the metal conductive layer; a polymer layer is printed on the surface of the transition layer, and material components of the polymer layer are completely or partially compatible with solute components of the polymer solution. By means of the method, stable spreading and adhesion of the polymer on the surface of the metal layer and stable combination of the polymer and the metal layer can be achieved under the normal-temperature and normal-pressure conditions, and the technical bottleneck that a traditional planar metal-polymer multilayer heterostructure hot-pressing combination method and other methods cannot be suitable for a complex curved surface structure is broken through.

The purpose of this disclosure is to provide an adhesive suitable for bonding aluminum substrates to other substrates, without a primer, and that balances high bond strength, adhesion breaking, and long-term resistance to damp heat. By combining a polyol base comprising a polyol, a phosphate compound, and a monohydric alcohol with a polyisocyanate curing agent, the adhesion of the phosphate compound to aluminum is ensured during adhesive application, thus improving bond strength. Furthermore, by utilizing a monohydric alcohol to adjust the degree of crosslinking in the coating film and establishing the initiation point for adhesion breaking, stable bond strength can be achieved.

The present application relates to the technical field of intelligent sensing system, in particular to a mortar bonding strength detection method and device. The present application firstly carries out multi-dimensional synchronous sampling on displacement, pulling force and pulling force growth rate in the pulling process, eliminates the misjudgment risk of single threshold being easily disturbed, and provides reliable data basis for subsequent analysis; secondly, through analyzing the cooperative fluctuation characteristics of displacement and pulling force, a nonlinear discrete index is determined to accurately distinguish the gap free state and the effective loading state, and the sensing accuracy under complex working conditions is significantly improved; then, the pulling force growth rate and the nonlinear discrete index are fused to quantize the impact risk caused by the coupling of high speed and free in real time, and the active accumulation and sensitive control of the risk are realized; finally, according to different pulling contact stages, the control strategy is adaptively switched, the overshoot risk is eliminated from the physical root, the detection process is stable and reliable, the accuracy of mortar bonding strength detection is effectively improved, and the possibility of low strength detection is reduced.

The invention discloses a coupling agent modification method for improving the bonding strength of a waste glass-based geopolymer coating. In order to solve the technical problems that an existing geopolymer coating is low in bonding strength (1.5-2.5 MPa) and the modification effect of a single coupling agent is limited (2.1-3.2 MPa), a titanate coupling agent (0.5-1.0 wt.%) is adopted for interface modification, and the titanate coupling agent can be independently used or compounded with graphene oxide (0.3-1 wt.%) for modification. An oxygen-containing functional group of the graphene oxide provides an additional reaction site for the coupling agent, and the lamellar structure improves the interface dispersity of the coupling agent and realizes 1 + 1gt; and 2, the synergistic enhancement effect is achieved. The bonding strength is improved to 5.6 MPa from 1.8 MPa of a basic coating and is obviously superior to that of independent modification (3.6-4.3 MPa) of a titanate coupling agent or independent modification (3.1 MPa) of graphene oxide, and the synergistic enhancement effect is obvious. The method is simple in process and remarkable in effect, and an effective interface modification scheme is provided for engineering application of the waste glass-based geopolymer coating.

The invention relates to a wafer bonding strength prediction method based on photoelectron spectroscopy. The method comprises the following steps: S1, carrying out surface cleaning pretreatment on a wafer sample; s2, cleaning and activating the surface of the wafer sample through plasma, and modifying the surface of the wafer sample; s3, acquiring an X-ray photoelectron spectroscopy; s4, carrying out translation correction on the X-ray photoelectron spectroscopy based on the C1s energy spectrum; and S5, obtaining the bonding strength based on the N1s energy spectrum after translation correction. Compared with the prior art, the method has the advantages that the bonding strength before bonding is predicted, and the problem that destructive experiments need to be carried out in a traditional bonding strength measuring means is effectively solved through nearly lossless photoelectron spectroscopy detection.

The invention relates to the technical field of welding, and particularly provides a performance evaluation method of an alloy for a flux core of a high-temperature titanium alloy laser welding wire. The performance evaluation method comprises the following steps: S1, carrying out multiphase stabilization theoretical calculation on key alloy elements in a to-be-evaluated alloy based on critical equivalents of the alloy elements to obtain strength equivalents; s2, calculating an average covalent bond strength Bo value and an average d orbital energy level Md value of the to-be-evaluated alloy; s3, calculating the electron concentration Ne of the alloy to be evaluated; s4, carrying out geometric optimization on the crystal structure calculation model of the to-be-evaluated alloy to obtain an optimized calculation model; according to the optimization calculation model, calculating an elastic constant of the to-be-evaluated alloy through a stress-strain method; and S5, the ductility and brittleness of the to-be-evaluated alloy are judged, and composition design of the flux core of the welding wire is completed. The evaluation method provided by the invention can predict the high-temperature strength, plasticity, thermal stability and precipitation behavior of the alloy based on the alloy components.

The invention relates to the technical field of material performance detection, and discloses a method for evaluating the bonding strength of secondary particles. The method comprises the following steps: S1, obtaining a first quantity density distribution curve of particle size distribution of a secondary particle sample to be detected; s2, destroying the secondary particle sample to be detected to obtain a second quantity density distribution curve of the particle size distribution of the destroyed sample; s3, performing first-order derivative function calculation on the first quantity density distribution curve to obtain a first-order derivative function curve, and obtaining granularity values corresponding to points of the first-order derivative function curve from positive to negative; and S4, determining a first proportion and a second proportion of the particle size values in the to-be-detected sample and the damaged sample respectively, and evaluating according to the intensity factor A. The method for evaluating the bonding strength of the secondary particles, provided by the invention, is simple and easy to operate, can effectively evaluate the bonding strength of the secondary particles, and is particularly suitable for evaluating the bonding strength of a negative electrode material of a lithium ion battery.

The invention discloses a polyetheretherketone and resin bonding strength enhancing method, and relates to the field of polyetheretherketone and resin bonding strength enhancement, and the method comprises the following steps: step 1, surface purification; step 2, sulfonation etching; 3, preparing a solution; step 4, carrying out ultraviolet grafting; step 5, deep cleaning; step 6, bonding a prime coat; and step 7, resin bonding. According to the technical scheme, breakthroughs are made in three aspects of bonding strength, process safety and durability, and a PEEK-resin interface which is high in strength, high in durability and free of mechanical damage is achieved on the premise of simplifying the process and guaranteeing safety through double-scale cooperation of sulfonated micropores and ultraviolet POSS grafting, so that the service life of the PEEK-resin interface is prolonged, and the service life of the PEEK-resin interface is prolonged. The defects that existing physical, chemical and coating technologies are short in aging, high in energy consumption or weak in binding force and the like are overcome.

The utility model discloses a drawing head for testing the tensile bonding strength of tile glue. The drawing head comprises a drawing component A, a drawing component B and a connecting piece, the drawing component A is convex, and a transverse through hole is formed in the side surface of the convex part of the drawing component A; the drawing component B is concave, and two side surfaces of the drawing component B are respectively provided with a through hole corresponding to the transverse penetrating through hole formed in the convex part of the drawing component A; and the drawing component A and the drawing component B are assembled into a regular blocky drawing head by the connecting piece through the transverse through hole in the drawing component A and the two corresponding through holes in the drawing component B. According to the drawing head for testing the tensile bonding strength of the ceramic tile adhesive, the problem that a conventional drawing head is easy to wear and deform in the cleaning and repeated use processes is solved, meanwhile, burning, scalding and fire accidents are avoided, irritant gas harmful to human health is reduced, and the labor cost is reduced.