CN115078480A - Method for rapidly detecting sintering microcrack of NTC spindle - Google Patents
Method for rapidly detecting sintering microcrack of NTC spindle Download PDFInfo
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- CN115078480A CN115078480A CN202210731303.5A CN202210731303A CN115078480A CN 115078480 A CN115078480 A CN 115078480A CN 202210731303 A CN202210731303 A CN 202210731303A CN 115078480 A CN115078480 A CN 115078480A
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- 238000000034 method Methods 0.000 title claims abstract description 23
- 238000005245 sintering Methods 0.000 title claims abstract description 18
- 238000001514 detection method Methods 0.000 claims abstract description 32
- 239000011248 coating agent Substances 0.000 claims abstract description 7
- 238000000576 coating method Methods 0.000 claims abstract description 7
- 238000005507 spraying Methods 0.000 claims description 11
- 238000007689 inspection Methods 0.000 claims description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 7
- 229910021389 graphene Inorganic materials 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 7
- 230000002159 abnormal effect Effects 0.000 claims description 4
- 238000003618 dip coating Methods 0.000 claims description 3
- 238000005259 measurement Methods 0.000 claims description 3
- 238000012360 testing method Methods 0.000 claims description 2
- 238000000462 isostatic pressing Methods 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 239000000843 powder Substances 0.000 description 4
- 239000000919 ceramic Substances 0.000 description 3
- 238000011161 development Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
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- 238000004891 communication Methods 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance
- G01N27/24—Investigating the presence of flaws
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance
- G01N27/221—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance by investigating the dielectric properties
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Abstract
The invention discloses a method for quickly detecting sintering microcracks of an NTC spindle, which comprises the following steps: s1: coating electrode layers on opposite end faces of the product to form a first electrode layer and a second electrode layer; s2: applying a first voltage and a second voltage at corresponding resonant frequencies to the first electrode layer and the second electrode layer respectively; s3: the first voltage and the second voltage are respectively connected with a first detection device and a second detection device: s4: and the first detection device and the second detection device acquire corresponding dielectric loss values, and the dielectric loss values are used for judging whether the product has cracks. When cracks are generated on the surface of the NTC spindle, the resistance of the dielectric loss value changes, the detection circuit is electrically connected with the first electrode and the second electrode respectively, the voltage output can be converted into a resistance value, and the size of the cracks on the surface of the NTC spindle can be judged; further, when the dielectric loss value is less than a predetermined value, the inside of the product has cracks.
Description
Technical Field
The invention relates to the technical field of sintered thermistor detection, in particular to a method for quickly detecting sintering microcracks of an NTC spindle.
Background
With the development of science and technology, ceramic NTC thermistors are widely used in the industries of communication, new energy vehicles, energy storage, medical treatment, household appliances and the like. In recent years, the forming process of the ceramic NTC thermistor generally adopts an isostatic pressing process. The isostatic pressing process has the advantages of simple operation, large density and uniformity of pressed products and the like. The isostatic pressing process is to place the prepared powder in a cuboid or cylindrical mold (a product pressed into a certain shape is called a spindle and shown in the following figure), pre-press the powder, place the powder in isostatic pressing with the pressure of more than 150mpa, and place the powder in a sintering furnace for sintering after pressing. The isostatic pressing spindle has a relatively large size, and cracks are easily generated due to stress action in the stages of temperature rise, heat preservation and temperature reduction in the sintering process. The cracks are not necessarily on the surface of the spindle and are possibly in the interior of the spindle, and the cracks are smaller. The prior method for checking whether the spindle has cracks generally adopts the method of cutting the spindle, and the cracks are not necessarily visible because the cracks are slightly cut. The existing detection method is generally applicable to a sampling inspection mode, so that whether the products in the batch have problems or not is judged, but the problem of missing inspection still exists, and with the development of scientific technology, the requirements on the thermistor are higher and higher, so that a rapid inspection method for a single product is needed.
Disclosure of Invention
The invention mainly aims to provide a method for rapidly inspecting sintering microcracks of an NTC spindle, which aims to realize rapid inspection of single products and can obtain the conditions of internal cracks or external cracks of the products.
In order to achieve the purpose, the invention provides a method for rapidly testing sintering microcracks of an NTC spindle, which comprises the following steps:
s1: coating electrode layers on opposite end faces of the product to form a first electrode layer and a second electrode layer;
s2: applying a first voltage and a second voltage at corresponding resonant frequencies to the first electrode layer and the second electrode layer respectively;
s3: the first voltage and the second voltage are respectively connected with a first detection device and a second detection device:
s4: and the first detection device and the second detection device acquire corresponding dielectric loss values, and the dielectric loss values are used for judging whether the product has cracks.
Preferably, when the dielectric loss value is less than a predetermined value, the inside of the product has cracks.
Preferably, when the dielectric loss value is greater than a predetermined value, the outer surface of the product has cracks.
Preferably, the dielectric loss value is a resistance value, and the resistance value calculation formula is as follows: and R is rho l/S.
Preferably, the electrode is a graphene material.
Preferably, the electrode layer is attached to the outer wall surface of the product by spraying or single-side dip coating,
preferably, when the spraying mode is adopted, the spraying measurement can be carried out for multiple times, so that the average value of the dielectric loss values is obtained.
Preferably, the first detection device and the second detection device are respectively connected with a first resistor and a second resistor, the first resistor and the second resistor are respectively connected with a first filter circuit and a second filter circuit, and abnormal wave bands generated by the first voltage and the second voltage in the dielectric loss value can be filtered through the first resistor, the first filter circuit, the second resistor and the second filter circuit.
According to the technical scheme, when cracks are generated on the surface of the NTC spindle, the resistance of the dielectric loss value changes, the detection circuit is electrically connected with the first electrode and the second electrode respectively, the voltage output can be converted into the resistance value, and therefore the size of the cracks on the surface of the NTC spindle can be judged; in addition, when the dielectric loss value is less than a predetermined value, cracks are formed inside the product; when the dielectric loss value is larger than a preset value, the outer surface of the product has cracks; meanwhile, the size of the crack inside or outside the metal can be judged according to the ratio of the resistance value to the preset value.
Drawings
Fig. 1 is a schematic diagram of a product.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.
It should be noted that if directional indications (such as … …, which is up, down, left, right, front, back, top, bottom, inner, outer, vertical, transverse, longitudinal, counterclockwise, clockwise, circumferential, radial, axial) are provided in the embodiments of the present invention, the directional indications are only used for explaining the relative position relationship, motion condition, etc. of the components at a specific posture (as shown in the attached drawings), and if the specific posture is changed, the directional indications are changed accordingly.
In addition, if there is a description relating to "first" or "second", etc. in the embodiments of the present invention, the description of "first" or "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.
As shown in fig. 1, a method for rapidly inspecting NTC spindle sintering microcracks comprises the following steps:
s1: coating electrode layers on opposite end faces of the product to form a first electrode layer and a second electrode layer;
s2: applying a first voltage and a second voltage at corresponding resonant frequencies to the first electrode layer and the second electrode layer respectively;
s3: the first voltage and the second voltage are respectively connected with a first detection device and a second detection device:
s4: and the first detection device and the second detection device acquire corresponding dielectric loss values, and the dielectric loss values are used for judging whether the product has cracks.
When cracks are generated on the surface of the NTC spindle, the resistance of the dielectric loss value changes, the detection circuit is electrically connected with the first electrode and the second electrode respectively, the voltage output can be converted into a resistance value, and the size of the cracks on the surface of the NTC spindle can be judged; in addition, when the dielectric loss value is less than a predetermined value, cracks are formed inside the product; when the dielectric loss value is larger than a preset value, the outer surface of the product has cracks; meanwhile, the size of the crack inside or outside the metal can be judged according to the ratio of the resistance value to the preset value.
When the product is a cylinder, two opposite circles of the cylinder can be coated so as to obtain corresponding resistance, but when the length of the cylinder is greater than the voltage of corresponding resonant frequency, piezoelectric loss of the voltage is easily caused, electrode layers can be coated on the left side and the right side of the cylinder in a spraying mode so as to reduce detection errors caused by the piezoelectric loss; when the product is rectangular or irregular, the crack inside the product can be mainly detected, and the crack outside the product can be secondarily detected.
When the dielectric loss value is smaller than a preset value, a crack exists in the product, when the surface of the product is a normal value, if the crack exists in the product, the piezoelectric loss is smaller than a corresponding value (namely, the resistance value is smaller), namely, the product can be understood as a resistor through volume ratio judgment, and when the volume of the resistor is larger, the resistance value is larger; when cracks appear on the surface of the product, the judgment of the internal cracks can be obtained through multiple times of detection or detection of multiple end faces.
When the dielectric loss value is larger than a preset value, the outer surface of the product has cracks, and when the inner part of the product is a normal value and the outer surface of the product has cracks, the larger the coating area of the electrode is, and the larger the corresponding resistance value is.
The dielectric loss value is a resistance value, and the resistance value calculation formula is as follows: r is rho l/S, can inspect the product through simple resistance formula fast whether up to standard, detects fast and simply, can be applicable to most processing places, is favorable to the detection of single product, has effectively improved the high-quality product rate of product.
The electrode is graphene materials, can reduce other interference factors through graphene materials, and graphene materials is lower to ceramic NTC thermistor's interference coefficient simultaneously, and under the non-full surface coating's the condition, graphene materials can not need to get rid of also can normal use, and the stability in use is better, because graphene materials's interference factor is stronger.
The electrode layer is attached to the outer wall surface of the product in a spraying mode or a single-side dip-coating mode, when the volume of the product is small, a precise coating mode is generally adopted, detection is achieved by covering the electrode layer uniformly, and when the volume of the product is large, the electrode layer can be placed in electrode liquid to dip-coat the electrode layer with a large thickness.
When the electrode layer is in a spraying mode, multiple spraying measurements can be carried out, so that the average value of the dielectric loss value is obtained, the judgment of the electrode layer on the resistance value can be measured for multiple times through multiple spraying, so that external cracks and internal cracks are judged, when the electrode layer reaches a preset value, the interference coefficient of the external cracks is reduced, for example, when the electrode layer is 1 and the electrode layer is 2, the resistance coefficients are both smaller than the preset value, and when the coefficient of the electrode layer is 3, the size of the internal cracks of the product can be judged.
The first detection device and the second detection device are respectively connected with a first resistor and a second resistor, the first resistor and the second resistor are respectively connected with a first filter circuit and a second filter circuit, and abnormal wave bands generated by the first voltage and the second voltage in the medium loss value can be filtered through the first resistor, the first filter circuit, the second resistor and the second filter circuit.
When there is a crack in both the inside and outside, the resistance is abnormal, and therefore it is necessary to determine whether the inside crack or the outside crack by measuring multiple surfaces and measuring a plurality of times, or to determine the size of the inside crack by eliminating the influence of the outside crack.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (8)
1. A method for rapidly testing sintering microcracks of an NTC spindle is characterized by comprising the following steps:
s1: coating electrode layers on opposite end faces of the product to form a first electrode layer and a second electrode layer;
s2: applying a first voltage and a second voltage at corresponding resonant frequencies to the first electrode layer and the second electrode layer respectively;
s3: the first voltage and the second voltage are respectively connected with a first detection device and a second detection device:
s4: and the first detection device and the second detection device acquire corresponding dielectric loss values, and the dielectric loss values are used for judging whether the product has cracks.
2. The NTC spindle sintering microcrack rapid inspection method of claim 1, wherein: when the dielectric loss value is less than a predetermined value, cracks are formed in the interior of the product.
3. The NTC spindle sintering microcrack rapid inspection method of claim 1, wherein: when the dielectric loss value is greater than a predetermined value, the outer surface of the product has cracks.
4. The NTC spindle sintering microcrack rapid inspection method of claim 1, wherein: the dielectric loss value is a resistance value, and the resistance value calculation formula is as follows: and R is rho l/S.
5. The NTC spindle sintering microcrack rapid inspection method of claim 1, wherein: the electrode is a graphene material.
6. The NTC spindle sintering microcrack rapid inspection method of claim 1, wherein: the electrode layer is attached to the outer wall surface of the product in a spraying mode or a single-side dip-coating mode.
7. The method for rapidly inspecting NTC spindle sintering microcracks of claim 6, wherein: when the spraying mode is adopted, multiple spraying measurements can be carried out, so that the average value of the dielectric loss values is obtained.
8. The NTC spindle sintering microcrack rapid inspection method of claim 1, wherein: the first detection device and the second detection device are respectively connected with a first resistor and a second resistor, the first resistor and the second resistor are respectively connected with a first filter circuit and a second filter circuit, and abnormal wave bands generated by the first voltage and the second voltage in the medium loss value can be filtered through the first resistor, the first filter circuit, the second resistor and the second filter circuit.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210731303.5A CN115078480A (en) | 2022-06-24 | 2022-06-24 | Method for rapidly detecting sintering microcrack of NTC spindle |
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| CN202210731303.5A CN115078480A (en) | 2022-06-24 | 2022-06-24 | Method for rapidly detecting sintering microcrack of NTC spindle |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5969532A (en) * | 1996-05-09 | 1999-10-19 | Seiko Epson Corporation | Method of inspecting crack in ceramic substrate |
| US20110060536A1 (en) * | 2009-09-09 | 2011-03-10 | Maria Qing Feng | Method and Apparatus for Inspecting Crack in Ceramic Body |
| CN102565133A (en) * | 2010-12-09 | 2012-07-11 | 日本发条株式会社 | Method of and apparatus for detecting cracks in piezoelectric element |
| KR20190078782A (en) * | 2017-12-27 | 2019-07-05 | 울산과학기술원 | Method of detecting damage of the structure |
| CN110487165A (en) * | 2019-08-23 | 2019-11-22 | 北京石墨烯技术研究院有限公司 | Metal Crack detection sensor and system |
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2022
- 2022-06-24 CN CN202210731303.5A patent/CN115078480A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5969532A (en) * | 1996-05-09 | 1999-10-19 | Seiko Epson Corporation | Method of inspecting crack in ceramic substrate |
| US20110060536A1 (en) * | 2009-09-09 | 2011-03-10 | Maria Qing Feng | Method and Apparatus for Inspecting Crack in Ceramic Body |
| CN102565133A (en) * | 2010-12-09 | 2012-07-11 | 日本发条株式会社 | Method of and apparatus for detecting cracks in piezoelectric element |
| KR20190078782A (en) * | 2017-12-27 | 2019-07-05 | 울산과학기술원 | Method of detecting damage of the structure |
| CN110487165A (en) * | 2019-08-23 | 2019-11-22 | 北京石墨烯技术研究院有限公司 | Metal Crack detection sensor and system |
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