CN202024831U - Detection system of metal powder laser rapid shaping temperature field - Google Patents

Detection system of metal powder laser rapid shaping temperature field Download PDF

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Publication number
CN202024831U
CN202024831U CN2011200019207U CN201120001920U CN202024831U CN 202024831 U CN202024831 U CN 202024831U CN 2011200019207 U CN2011200019207 U CN 2011200019207U CN 201120001920 U CN201120001920 U CN 201120001920U CN 202024831 U CN202024831 U CN 202024831U
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temperature
detection system
thermopair
blind hole
temperature field
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CN2011200019207U
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刘伟军
卞宏友
赵宇辉
李论
王福雨
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Shenyang Institute of Automation of CAS
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Shenyang Institute of Automation of CAS
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Abstract

The utility model relates to a detection system of a metal powder laser rapid shaping temperature field, and belongs to the field of temperature field detection technology. The detection system includes a plurality of high temperature thermocouples which is separately arranged into through holes and blind holes of a shaped base plate, a transition card, a data acquisition module, and a computer with a built-in temperature measurement system software. The thermocouples are connected with the data acquisition module, and the data acquisition module is connected with the computer via the signal transition card. The detection system is not sensitive to the external processing circumstances, and can guarantee the measuring precision. Through the optimized arrangement of the temperature measurement points, a more accurate temperature field distribution can be obtained. The detection system integrates the advantages of the direct temperature measurement and the indirect temperature measurement, and the thermocouples in the blind holes do not contact a shaped workpiece directly, so the thermocouples can be used repeatedly, thus saving the cost. Through a plurality of experiments, the law of difference between the interior temperature field of a shaped workpiece and the base plate temperature field is obtained, so the number of the temperature thermocouple in the through holes can be reduced, and consequently the cost is reduced.

Description

The detection system in a kind of metal powder laser quick shaping temperature field
Technical field
The present invention relates to metal powder laser Rapid Prototyping technique and temperature field detection technique, be specially a kind of detection system of metal powder laser quick shaping temperature field of, blind hole thermometric logical based on thermopair.
Background technology
The direct Rapid Prototyping technique of laser metal is an advanced manufacturing technology that grows up in conjunction with synchronous coaxial feeding laser melting and coating technique on the rapid prototyping technology basis that occurs the latter stage eighties.It relates to the gordian technique in fields such as machinery, laser, computer-aided design (CAD), computer-aided manufacturing, computer numerical control (CNC), material science.It has broken through the limitation of traditional fast forming process and moulding material, be in all multi-methods of present quick shaping research at most, the most rising new manufacture.But in the metal parts laser fast forming was made, distortion that formation of parts often occurs and problems of crack were to hinder it to expand the biggest obstacle of using; The factor that causes these problems to occur is a lot, but basic reason is the temperature field skewness that the laser beam spot heating is caused, and causes at formation of parts to have the stress concentration phenomenon, and then causes strain cracking.Therefore, disclosing forming process temperature field evolution rule is prerequisite and the basis of optimizing technological parameter, regulating and controlling temperature field distribution, reducing stress concentration and improve forming quality, is the necessary means that discloses forming process temperature field evolution rule and forming process temperature field efficient real time is detected.
Temp measuring method commonly used at present mainly contains two kinds: contact temperature-measuring and contactless temperature-measuring.The normal at present contactless temperature-measuring method that adopts based on infrared thermometer, but infrared thermometer is subjected to the interference ratio of processing environment bigger, and involve great expense, the more important thing is that it only can detect the bath temperature and the specimen surface temperature of forming process, can't detect Forming Workpiece internal temperature field, but the field distribution of Forming Workpiece internal temperature is directly to influence the principal element that the formation of parts internal stress distributes, and therefore, the field distribution of Forming Workpiece internal temperature is the emphasis of temperature detection.
Thermocouple temperature measurement directly contacts Forming Workpiece, belongs to the direct temperature measurement method, and temperature survey is accurate, is the important method that detects the field distribution of workpiece internal temperature.In addition, owing to optimize in the technological parameter forming experiment, need a large amount of repeated temperature fields test experience at new material.And the direct contact workpiece thermometric of thermopair, it promptly is set in Forming Workpiece inside, belongs to once to consume and can not utilize again, has increased the detection cost.
Summary of the invention
At the technical matters of above-mentioned existence, the object of the invention is to provide the detection system in a kind of metal powder laser quick shaping temperature field, realizes accurately and low-cost the detection.
Technical scheme of the present invention is as follows:
The present invention includes: the computing machine of a plurality of pyrometer couples, transition card, data acquisition module and built-in temp measuring system software in forming board through hole and the blind hole of being placed in, thermopair is connected with data acquisition module, and data acquisition module by the conversion of signals card connection on computers.
Described thermopair places the through hole or the blind hole of forming board by its mounting structure, and its mounting structure comprises:
Substrate holder places the substrate below, and is fixed on the bracket base;
Bottom platen is positioned at substrate holder thermopair below, is respectively installed with on each thermopair and the contacted spring of bottom platen, and bottom platen is provided with at least three and the contacted set screw of bracket base.
Blind hole and through hole that forming board described in the present invention is provided with, one group in twos, wherein the distance of the bottom of blind hole and upper surface of base plate is 0.1-2mm.The temperature-measuring range of described pyrometer couple is 0-1800 ℃, and the actual point for measuring temperature of thermopair is exposed outside.Described transition card changes the RS485 communication for the RS232 communication.
The present invention has following advantage:
1. simple in structure, save cost.The thermocouple temperature measurement system is not vulnerable to the influence of extraneous processing environment in the detection method that the present invention proposes, and can guarantee measuring accuracy; Secondly the thermocouple measurement system price is cheap, can obtain genuine and believable temperature field data with lower cost.
2. but point for measuring temperature preferred arrangement.The present invention can be according to the concrete shape and the actual processing experience of formation of parts, at the position of shaping track complexity and the position of the cracking that easily deforms point for measuring temperature is set more, the finer temperature field that can obtain the emphasis sensitive part like this distributes, and provides theoretical foundation for finding the method that suppresses strain cracking.
3. the advantage of integrated direct temperature measurement and indirect temperature-measuring.The present invention adopts the scheme of logical blind hole thermopair contrast thermometric, and thermopair directly contacts Forming Workpiece in the through hole, belongs to the direct temperature measurement means, and temperature survey is accurate; And the thermopair in the blind hole does not directly contact Forming Workpiece, belongs to indirect temperature-measuring, and is reusable, saves cost.By repeatedly experiment, find the difference rule of Forming Workpiece inside and substrate temperature field, can reduce through hole temperature thermocouple quantity gradually, reduce cost.
4. system stability is higher, extensibility good, software function is powerful.The present invention has used RS232 changes the RS485 transition card, has remedied some shortcomings of RS-232-C interface, has improved the stability of data acquisition precision and temp measuring system.Can measure acquisition module, temp measuring system favorable expandability according to the coupling respective numbers of how much expanding of measurement point.The software Development instrument adopts popular in the world in recent years visual programming language-Labview, makes the thermometric software of native system have advantages such as man-machine interaction is good, powerful.This software has realized that temperature data measures, gathers and monitor processing in real time, has real time temperature curve display function, forming temperature data Microsoft Excel export function and high low temperature warning function, has satisfied the needs of practical application.
Description of drawings
Fig. 1 is the layout synoptic diagram of substrate point for measuring temperature of the present invention.
Fig. 2 is the A-A cross-sectional schematic of Fig. 1.
Fig. 3 is the mounting structure synoptic diagram of thermopair among the present invention.
Fig. 4 is a temp measuring system structured flowchart of the present invention.
Fig. 5 is the man-machine interface figure of software of the present invention.
Fig. 6 is a temp measuring system software control flow chart of the present invention.
Among the figure: 1. substrate, 2. through hole, 3. blind hole, 4. substrate holder, 5. thermopair, 6. spring, 7. bottom platen, 8. set screw, 9. bracket base.
Embodiment
Below in conjunction with drawings and Examples the present invention is described in further detail.
Embodiment 1: as shown in Figure 4, this routine described detection system comprises: the computing machine of a plurality of pyrometer couples 5, transition card, data acquisition module and built-in temp measuring system software in be placed in forming board through hole 2 and the blind hole 3, thermopair 5 is connected with data acquisition module, and data acquisition module by the conversion of signals card connection on computers.
Described thermopair is selected the bigger platinum-rhodium alloy thermopair of temperature-measuring range for use, the common used in industry pyrometer couple all exists the long shortcoming (greater than 20s) of thermal response time, the present invention exposes processing to the actual point for measuring temperature of thermopair, greatly improve the response speed (thermal response time is 1s) of thermopair, satisfied actual thermometric requirement.WRR-010, high temperature resistant 0-1800 ℃.Transition card adopts the RS232 communication to change the RS485 communication, remedies the defective that general microcomputer provides the RS-232-C interface of standard, has adopted this new interface standard of RS485 in the data acquisition link, has improved measuring accuracy and stability.The data acquisition module that adopts can be according to measurement point how much expand the coupling respective numbers, each data acquisition module contains the thermopair load module of 8 passages, and 24 sigma-delta ADC provide higher precision, precision〉0.1%, sampling rate 〉=10 HZ/ second, isolate 3000 VDC,, the input of 6 tunnel difference, 2 tunnel single-ended inputs, the thermocouple type that can insert has J, K, E, T, R, S, B etc., and built-in CJC is connected with thermopair, finishes the forming process temperature acquisition and measures.Computer-internal thermometric software has filtering, calibration link.
As shown in Figure 3, described thermopair 5 places the through hole 2 or the blind hole 3 of forming board 1 by its mounting structure, and its mounting structure comprises:
Substrate holder 4 places substrate 1 below, and is fixed on the bracket base 9; Be used for supporting the substrate 1 of laser fast forming, and play the function of fixing thermopair 5.Can promote bottom platen 7 by set screw 8 and vertically compress thermopair 5, make the thermopair 5 in the blind hole 3 fit tightly substrate 1 bottom, reduce temperature loss to greatest extent, improve measurement accuracy.
Bottom platen 7, be positioned at substrate holder 4 thermopairs 5 belows, be respectively installed with on each thermopair 5 and bottom platen 7 contacted springs 6, bottom platen 7 is provided with at least three and bracket base 9 contacted set screw 8, and this example adopts 4 set screw 8.
As shown in Figure 1 and Figure 2, blind hole 3 and through hole 2 that this example is preset at described forming board 1, one group in twos, wherein the distance of the bottom of blind hole 3 and substrate 1 upper surface is 0.1-2mm, this example is selected 0.1mm for use.The temperature-measuring range of described pyrometer couple 5 is 0-1800 ℃, and the actual point for measuring temperature of thermopair 5 is exposed outside.
Adopt the detection method of temperature field of the present invention detection system, be specially: the through hole 2 and the blind hole 3 of default several built-in pyrometer couples on forming board 1 diverse location, according to through hole 2 and blind hole 3 thermometric contrast simultaneously, obtain the concrete rule of the inner and substrate 1 internal temperature field difference of Forming Workpiece in the laser fast forming process, adopt the method for blind hole 3 thermometrics to obtain Forming Workpiece temperature inside field again.
The concrete rule of described laser fast forming process temperature field distribution, determine as follows: measure on forming board 1 diverse location temperature of pyrometer couples 5 in several through holes 2 and blind hole 3 simultaneously, temperature measurement data by thermopair 5 in same position blind hole 3 and the through hole 2 compares, obtain the distribution situation and the variation tendency of the inner and substrate 1 internal temperature field of Forming Workpiece under the different situations, Forming Workpiece inside and substrate 1 internal temperature field are analyzed, obtain the concrete rule of difference between the two.Thermopair 5 in the described through hole 2 is directly measured the Forming Workpiece internal temperature, and temperature survey is accurate; Thermopair 5 in the blind hole 3 is measured substrate 1 internal temperature.Because the through hole temperature thermocouple directly contacts and is set in Forming Workpiece inside, belong to and once consume and to utilize again, and the blind hole temperature thermocouple can be realized reusing; And optimize in the technological parameter forming experiment at new material, need a large amount of repeated temperature fields test experience, adopt thermopair blind hole thermometric can reduce the quantity consumed of thermopair, reduce and measure cost.In conjunction with thermopair through hole thermometric and thermopair blind hole thermometric comparative analysis result, can guarantee the accuracy in thermopair blind hole thermometric reflection laser fast forming temperature field.
The idiographic flow of this routine temperature field detection method is as follows:
(1) point for measuring temperature preferred arrangement and drill through blind hole in advance
As shown in Figure 1 and Figure 2, arrange that on the laser beam scan path of forming board 1 point for measuring temperature and preboring are some to blind hole and through hole, one group in twos of blind hole 3 and through hole 2, wherein the distance of the bottom of blind hole 3 and upper surface of base plate is 1mm.Drilling hole amount and position can process experience according to reality, and according to the deform sensitivity of cracking of the concrete size shape of formation of parts and formation of parts different structure position, in the actual measurement process, can also be optimized layout and boring to point for measuring temperature according to the concrete size shape of formation of parts.Position in shaping track complexity is provided with point for measuring temperature more, simultaneously according to actual processing experience, in the formation of parts cracked parts that easily deforms point for measuring temperature and drill through blind hole in advance is set, to obtain more accurate, the finer temperature field distribution results of Forming Workpiece strain cracking sensitive part more.
(2) thermopair is installed
As shown in Figure 3, thermopair 5 is inserted in each through hole 2 and the blind hole 3,, promote bottom platen 7 and vertically compress thermopair 5, to guarantee that thermopair 5 points for measuring temperature fit tightly substrate 1 in the blind hole 3 by regulating the set screw 8 on the bottom platen 7.
(3) temperature field is detected
Start the temp measuring system software (the software human-computer interaction interface as shown in Figure 5) of computing machine, laser fast forming process temperature field is detected in real time by data acquisition module control thermopair.As shown in Figure 6, this routine described temp measuring system software adopts Labview exploitation temp measuring system software, mainly utilizes the VISA module among the Labview to carry out the serial communication programming, and signal transfer protocol adopts ASCII command agreement.This software has realized that the temperature data of metal powder laser quick shaping process measures, gathers and monitor processing in real time, has real-time forming temperature curve display function, forming temperature data Microsoft Excel export function and high low temperature warning function.Its concrete control flow is:
Step 1): carry out the serial ports parameter configuration; As: the serial port resource title is selected COM1; Baud rate is set to 9600Baud; Data bit-rate is set to 8 bps; Parity check bit is set to none;
Step 2): carry out the setting of data sampling cycle, the sampling period is made as more than 1000 milliseconds; Because data acquisition is the mode of scan round for the employing of 8 path thermocouple load modules, the scanning of each passage needs 125 milliseconds consuming time, so the employing cycle is made as more than 1000 milliseconds;
Step 3): write the serial communication order, the order that this example writes is that the log-on data acquisition module carries out temperature data acquisition, and the communications protocol of employing is an ASCII command agreement, and promptly the input command form is an ASCII fromat;
Step 4): the temperature data of reading system data buffer, the described data layout that reads is a character string forms;
Step 5): the string data that reads in the step 4) is carried out Data Format Transform: promptly read each in the character string successively, it is converted to metric numeric format one by one;
Step 6): temperature data is removed the processing of making an uproar; Therefore the temperature-measuring range of thermopair is 0-1800 ℃, less than 0 ℃ with greater than 2000 ℃ temperature measurement data, thinks that noise data is removed;
Step 7): temperature data is carried out Filtering Processing, and filtering mode is the pointwise medium filtering; The data structure of a stacking-type promptly is set, gathers 5 temperature datas at every turn, data are carried out the size ordering,, and then gather next group data the output of the data in the middle of coming;
Step 8): carry out the real-time demonstration of temperature curve, carry out the setting of high low-temperature warning link simultaneously; The temperature-measuring range of thermopair is 0-1800 ℃, therefore carries out high temperature alarm when real time temperature exceeds 1800 ℃; And pyrometer couple temperature measurement accuracy when temperature is lower than 200 ℃ is not high, therefore carries out low-temperature warning when real time temperature is lower than 200 ℃;
Step 9): temperature data is written among the Microsoft Excel; Be about to eight road temperature datas and be integrated into the array form, array is written among the Microsoft Excel, realized the Microsoft Excel output of temperature acquisition data.
(4) thermopair through hole and blind hole thermometric and temperature field comparative analysis simultaneously
Adopt thermopair through hole and blind hole while thermometric: the thermopairs in the through hole 2 directly contact with Forming Workpiece, what measure is the temperature variation of inner certain point of Forming Workpiece, and the temperature data of gathering each point for measuring temperature different time has just obtained the regularity of distribution and the evolution trend of workpiece internal temperature field in the forming process; And the direct contact substrate 1 of thermopair in each blind hole 3, measurement be the temperature variation of forming board 1 inner certain point, gather each point for measuring temperature different time temperature data just obtained the regularity of distribution and the evolution trend of substrate 1 internal temperature field in the forming process; The temperature data of thermopair in same position blind hole 3 and the through hole 2 is analyzed, can obtains the temperature variations and the concrete difference of Forming Workpiece internal temperature field and substrate 1 internal temperature field, and sum up concrete rule.
(5) thermopair blind hole thermometric and temperature field analysis
Optimize in the technological parameter forming experiment at new material, need a large amount of repeated temperature fields test experience, adopt thermopair blind hole temp measuring method, realize the thermopair repeated use, reduce and measure cost.In conjunction with thermopair through hole thermometric and thermopair blind hole thermometric comparative analysis result, with the anti-Forming Workpiece internal temperature field of releasing, the substrate internal temperature field of thermopair blind hole thermometric gained, also can accurately analyze the regularity of distribution and the variation tendency of Forming Workpiece internal temperature field.
Embodiment 2: this example is identical with embodiment 1 detection system structure and detection method, and different is: at blind hole 3 and through hole 2 that described forming board 1 is preset, one group in twos, wherein the distance of the bottom of blind hole 3 and substrate 1 upper surface is 2mm.
Embodiment 3: this example is identical with embodiment 1 detection system structure and detection method, and different is: at blind hole 3 and through hole 2 that described forming board 1 is preset, one group in twos, wherein the distance of the bottom of blind hole 3 and substrate 1 upper surface is 1mm.
Embodiment 4: this example is identical with embodiment 1 detection system structure and detection method, and different is: at blind hole 3 and through hole 2 that described forming board 1 is preset, one group in twos, wherein the distance of the bottom of blind hole 3 and substrate 1 upper surface is 0.5mm.
Embodiment 5: this example is identical with embodiment 1 detection system structure and detection method, and different is: at blind hole 3 and through hole 2 that described forming board 1 is preset, one group in twos, wherein the distance of the bottom of blind hole 3 and substrate 1 upper surface is 0.2mm.
Embodiment 6: this example is identical with embodiment 1 detection system structure and detection method, and different is: at blind hole 3 and through hole 2 that described forming board 1 is preset, one group in twos, wherein the distance of the bottom of blind hole 3 and substrate 1 upper surface is 0.8mm.
Embodiment 7: this example is identical with embodiment 1 detection system structure and detection method, and different is: at blind hole 3 and through hole 2 that described forming board 1 is preset, one group in twos, wherein the distance of the bottom of blind hole 3 and substrate 1 upper surface is 1.2mm.
Embodiment 8: this example is identical with embodiment 1 detection system structure and detection method, and different is: at blind hole 3 and through hole 2 that described forming board 1 is preset, one group in twos, wherein the distance of the bottom of blind hole 3 and substrate 1 upper surface is 1.5mm.

Claims (5)

1. the detection system in a metal powder laser quick shaping temperature field, it is characterized in that comprising: the computing machine of a plurality of pyrometer couples, transition card, data acquisition module and built-in temp measuring system software in forming board through hole and the blind hole of being placed in, thermopair is connected with data acquisition module, and data acquisition module by the conversion of signals card connection on computers.
2. according to the detection system in the described metal powder laser quick shaping of claim 1 temperature field, it is characterized in that: described thermopair places the through hole or the blind hole of forming board by its mounting structure, and its mounting structure comprises:
Substrate holder places the substrate below, and is fixed on the bracket base;
Bottom platen is positioned at substrate holder thermopair below, is respectively installed with on each thermopair and the contacted spring of bottom platen, and bottom platen is provided with at least three and the contacted set screw of bracket base.
3. according to the detection system in claim 1 or 2 described metal powder laser quick shaping temperature fields, it is characterized in that: blind hole and through hole that described forming board is provided with, one group in twos, wherein the distance of the bottom of blind hole and upper surface of base plate is 0.1-2mm.
4. according to the detection system in claim 1 or 2 described metal powder laser quick shaping temperature fields, it is characterized in that: the temperature-measuring range of described pyrometer couple is 0-1800 ℃, and the actual point for measuring temperature of thermopair is exposed outside.
5. according to the detection system in the described metal powder laser quick shaping of claim 1 temperature field, it is characterized in that: described transition card changes the RS485 communication for the RS232 communication.
CN2011200019207U 2011-01-05 2011-01-05 Detection system of metal powder laser rapid shaping temperature field Expired - Fee Related CN202024831U (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113237564A (en) * 2021-05-07 2021-08-10 北京理工大学 High-temperature thermocouple multi-point temperature measurement clamp for ablation examination
CN113739929A (en) * 2021-08-27 2021-12-03 西安交通大学 High-space-time resolution temperature measurement system and method based on data fusion

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113237564A (en) * 2021-05-07 2021-08-10 北京理工大学 High-temperature thermocouple multi-point temperature measurement clamp for ablation examination
CN113739929A (en) * 2021-08-27 2021-12-03 西安交通大学 High-space-time resolution temperature measurement system and method based on data fusion

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