CN107908872B

CN107908872B - Reliability improvement method and device for tool magazine system

Info

Publication number: CN107908872B
Application number: CN201711131554.5A
Authority: CN
Inventors: 孙曙光; 张蒙; 申桂香; 张英芝
Original assignee: Shandong Normal University
Current assignee: Shandong Normal University
Priority date: 2017-11-15
Filing date: 2017-11-15
Publication date: 2020-06-26
Anticipated expiration: 2037-11-15
Also published as: CN107908872A

Abstract

The invention relates to a method and a device for improving the reliability of a tool magazine system, wherein the method comprises the following steps: step 1: analyzing potential faults of the tool magazine system by adopting a fault analysis method to obtain a key fault mode; step 2: and establishing a contradiction matrix based on a TRIZ analysis method, extracting a reliability improvement direction corresponding to the key fault mode in the contradiction matrix, and improving the reliability according to the direction.

Description

Reliability improvement method and device for tool magazine system

Technical Field

The invention relates to a method and a device for improving the reliability of a tool magazine system.

Background

With the increasingly fierce global market competition and the increasing demand of users on the individuation of product performance, the structure and function complexity of the numerical control machine tool is increasingly improved, and the numerical control machine tool gradually develops towards high performance, high precision and high reliability, so that higher requirements on the precision, the running speed and the reliability of an automatic tool changer are provided, and the research on the reliability problem of a tool magazine system is more and more important.

Currently, reliability improvement research is mainly focused on the following steps: according to a product failure mechanism, a subsystem with the largest harmfulness is searched by utilizing a failure mode, influence and harmfulness Analysis (FMECA) method, and a key subsystem is determined; according to the product Fault transmission relation, Fault Analysis is carried out by utilizing methods such as an event Tree, a GO method, a Fault Tree (FTA) and the like; and acquiring the influence degree of the sub-component faults and the like by means of the functional relation between each sub-component of the product and the reliability parameter of the whole machine. Although the above methods have been applied to reliability research from different angles, the research methods are too single and many ideas and experiences are based on to solve the surface reliability problem, often neglecting the implicit complex problem, so that the surface reliability problem cannot be really solved.

The tool magazine system provides a device for storing and replacing tools required in an automated process. The automatic tool changing mechanism and the tool magazine capable of storing a plurality of tools change the traditional production mode mainly by people. By means of the control of a computer program, various machining requirements such as milling, drilling, boring, tapping and the like can be met, the machining time course is greatly shortened, and the production cost is reduced, which is the biggest characteristic of a tool magazine system.

For fault analysis of a tool magazine system, FMECA analysis is generally adopted at present, and the obtained Risk Priority Number (RPN) value has a defect of multiple repetition numbers, and adverse effects on other functions are not considered when reliability improvement measures are taken, so that the fault analysis of the tool magazine system is insufficient. How to avoid these problems and improve reliability has not been a complete technical solution in the prior art.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a reliability improvement method of a tool magazine system, which is characterized in that TRIZ39 engineering parameters are adopted to study the faults of the tool magazine system on the basis of FMECA, the quantitative analysis of a Decision-Making Laboratory method (Decision-Making and Trial Evaluation Laboratory, DEMATEL) is used for realizing the fault mode classification and finding out a key fault mode, and then the reliability improvement of the tool magazine system is developed by using a contradiction matrix in the TRIZ theory.

The technical scheme of the invention is as follows:

a method of reliability improvement for a tool magazine system, comprising:

step 1: analyzing potential faults of the tool magazine system by adopting a fault analysis method to obtain a key fault mode;

step 2: and establishing a contradiction matrix based on a TRIZ analysis method, extracting a reliability improvement direction corresponding to the key fault mode in the contradiction matrix, and improving the reliability according to the direction.

Wherein, step 1 includes:

step 11: analyzing the potential fault of the tool magazine system by adopting an FMECA (failure mode-matching algorithm) analysis method to obtain a potential fault mode;

step 12: and classifying the potential fault modes by adopting a DEMATEL analysis method, and extracting key fault modes.

Wherein the step 12 comprises:

establishing a correlation matrix of the potential fault mode and the project parameters of the TRIZ39, transforming the correlation matrix to obtain parameters for quantifying the level of the potential fault mode, and extracting the potential fault mode represented by the parameters in a set range as a key fault mode.

Further, establishing a correlation matrix of the potential failure modes and the project parameters of the TRIZ39 includes:

scoring the correlation between the potential fault mode and the TRIZ39 engineering parameters, and establishing a first correlation matrix according to a scoring result;

the correlation between the TRIZ39 engineering parameters and each function of the tool magazine system is scored, and the weight value of the TRIZ39 engineering parameters to each function of the tool magazine system is calculated according to the weight value of each function of the tool magazine system;

and multiplying the elements of the first correlation matrix by the corresponding weighted values to obtain a correlation matrix of the potential fault mode and the project parameters of the TRIZ 39.

Further, transforming the correlation matrix to obtain parameters for quantifying the potential failure mode level includes:

and converting the correlation matrix into a direct correlation matrix, carrying out standardization operation on the direct correlation matrix, establishing a comprehensive influence matrix according to the standardized direct correlation matrix, and calculating the centrality and the reason degree of the potential fault mode according to the comprehensive influence matrix, wherein the centrality and the reason degree are used as parameters for quantizing the grade of the potential fault mode.

Further, establishing the contradiction matrix based on the TRIZ analysis method comprises the following steps:

and (3) establishing a two-dimensional contradiction matrix by respectively using the TRIZ39 engineering parameters as column parameters and row parameters, wherein elements in the contradiction matrix represent the invention principle of the TRIZ analysis method.

Further, extracting the reliability improvement direction corresponding to the key failure mode in the contradiction matrix comprises:

and extracting an invention principle corresponding to each key fault mode from the contradiction matrix, and establishing a reliability improvement direction according to the invention principle.

and extracting a plurality of invention principles from the contradiction matrix, and formulating a reliability improvement direction for solving the key fault mode by combining the plurality of invention principles.

In order to implement the method, the invention further provides a storage device, which stores a plurality of instructions, wherein the instructions are loaded by a processor and execute the following processing:

Furthermore, the invention also provides a reliability improving device of the tool magazine system, which comprises a processor, a control unit and a control unit, wherein the processor is used for realizing each instruction; and storage means for storing a plurality of instructions, the instructions being loaded by the processor and performing the following:

The invention has the beneficial effects that:

the invention provides a method for improving the reliability of a tool magazine system. According to the method, faults of the tool magazine system are researched by adopting TRIZ39 engineering parameters on the basis of FMECA, fault mode classification is realized by quantitative analysis of DEMATEL, a key fault mode is found out, and then reliability improvement of the tool magazine system is developed by using a contradiction matrix in the TRIZ theory.

(1) The potential fault mode of functional requirement is researched through the TRIZ39 engineering parameters, a correlation analysis mode of the fault mode and the engineering parameters is established, and reliability improvement cognition of reliability technicians on the tool magazine system is strengthened.

(2) And quantitatively analyzing by adopting a DEMATEL method, classifying the fault modes of the tool magazine system, and finding out key fault modes, thereby constructing an objective fault risk evaluation method and reducing errors caused by subjective judgment. Meanwhile, the method sorts the fault modes by means of reason degree and centrality degree, so that the Priority order is clearly improved, and the defect that the traditional Risk Priority Number (RPN) value has a plurality of repetition numbers can be overcome.

(3) Reliability improvement measures are provided by means of the problem solving principle given by the contradiction matrix table in the TRIZ theory, the problem that the conventional FMECA improvement measures only pay attention to the current problems but ignore the possible deterioration effect is solved, the reliability improvement measures of the tool magazine system are made more perfect, and the existing reliability problems can be solved really.

Drawings

FIG. 1 is a flow chart of the method of the present invention.

FIG. 2 is a diagram illustrating the results of the cause degree and the center degree according to an embodiment of the present invention.

The specific implementation mode is as follows:

the invention will be further illustrated with reference to the following examples and drawings:

it should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

As mentioned in the background art, the current research on reliability is limited to temporary solution and permanent solution, and is widely applied to Decision laboratory analysis (Decision Making laboratory) in various fields, so that reliability technicians can improve the capabilities of understanding special problems, identifying feasible schemes, solving complex problems and the like when facing the complex problems; the invention problem solving theory (triorea inesania isobutrychia zawatch, TRIZ) has systematic and structured bearing capacity for the problem solving mode, enables reliability technicians to analyze various valuable problems more accurately, and is suitable for improving the product reliability.

The FMECA is based on a fault mode, influences or consequences of faults are obtained by means of gradually exploring the influences of different faults of all components on system work, weak links in the existing design are comprehensively distinguished, and information is provided for evaluating and improving reliability of the system design. The FMECA is effectively executed, the fault mode can be analyzed, the influence of different faults of all components on system work can be obtained, the fault influence or the consequence can be obtained, weak links in design can be comprehensively distinguished, fault occurrence reasons can be discussed for evaluating and improving the system design, preventive measures can be taken or improvement countermeasures can be sought, the potential risk of subsequent change or remedy can be further reduced, and the product reliability can be improved.

DEMATEL is an effective method for analyzing the relationship between system components, and can determine the priority of scheme selection or activity improvement according to the degree of correlation and the degree of influence severity between system components. The method can effectively construct the causal relationship among the factors, the scheme evaluation architecture, the factor weight and the like, and is widely applied to the fields of environmental protection, society, commerce, management, engineering and the like.

The TRIZ theory is a systematic creative design method, which is used to solve various problems possibly encountered in the creative process so as to clarify and emphasize the contradiction existing in the system. In addition, the TRIZ theory has the ability to promote innovation and solve abstract problems, and can assist engineers to find innovative solutions for technical problems and product development processes, so as to replace inefficient blind search. The contradiction matrix is one of the tools for solving the problem, and is a 39 x 39 order matrix, in which i represents the improved characteristic, j represents the result of avoiding deterioration, and the number in the middle square of the matrix represents the 40 invention principles corresponding to i and j. The 39 engineering parameters that make up the contradiction matrix are the systematic conflict contradiction features that Altsuuller analyzes various engineering problem conditions to conclude. When the contradiction phenomenon is generated in the system improvement, the corresponding invention principle can be found by means of the contradiction matrix, and the thinking direction for solving the specific problem is provided.

To illustrate a specific technical mode of the present invention:

(1) FMECA analysis

According to the suggestions of related documents and reliability technicians, FMECA analysis is carried out on a tool magazine system of a numerical control machine tool product, namely a machining center, and the evaluation calculation shows that the first five items with the highest Risk Priority Number (RPN) in a potential failure mode of the product are respectively as follows: abnormality occurs in tool changing (RPN 315); the tool cannot be changed (RPN 180); the operation of the cutting tool (RPN 165) and the tool magazine is abnormal (RPN 165); the tool magazine motor is overloaded (RPN 160). However, in the latent failure mode obtained by simply adopting FMECA analysis, many repetition numbers of RPN occur, and we propose to improve by adopting the DEMATEL method for this defect, which is specifically referred to later.

TABLE 1 FMECA analysis

Tab.1 FMECA analysis

Step two: critical failure mode analysis

In order to establish a correlation matrix of the latent fault mode and the TRIZ39 engineering parameters, firstly, the correlation degree between the latent fault mode and the TRIZ39 engineering parameters is analyzed in an expert interview mode, and a first correlation matrix A of the latent fault mode and the engineering parameters is established.

Note: c₁-10. force; c₂-11. stress or pressure; c₃-12. shape; c₄-13. structural stability; c₅-14. intensity; c₂-21. power; c₂-25. waste of time; c₂-27. reliability; c₂-29. manufacturing accuracy; c₂-31 harmful side effects; c₂-36. device complexity; c₂-37. degree of difficulty in monitoring and testing; c₂Degree of automation 38. The rows of the matrix represent potential failure modes in 1.

After the first correlation matrix is established, the first correlation matrix needs to be improved, firstly, correlation matrices of subsystems and TRIZ39 engineering parameters, which are components of the tool magazine system, need to be established, and the correlation degree between the subsystems and the TRIZ39 engineering parameters is analyzed in an expert interview mode to establish the correlation matrices of the subsystems/functions and the engineering parameters. The correlation matrix is the integer part of table 2.

The evaluation of the importance of each function is performed by formula (1), for example, the weighting value of "drive system frequency converter" is 0.1346. Further, the weight value of each engineering parameter is calculated, for example, the weight value of "time waste" is 12.44%, and the weight value of "reliability" is 12.93%. As shown in table 2.

Weighting of single function importance

Wherein, i represents the ith function (i is 1,2, L, k), and j represents the jth RPN value (j is 1,2, L, n) in the ith function

TABLE 2 engineering parameter weight evaluation Table

Tab.2 Weight evaluation table of engineering parameters

See matrix B, for example, if the "No tool Change" and "stress or pressure" correlation value is 2, the "stress or pressure" weight value is 4.05%, so the weighted correlation value is 2 × 4.05.05% — 0.023

Next, we perform a series of transformations on the correlation matrix obtained by the above calculation, mainly using a DEMATEL method to establish a quantization index for screening key failure modes:

firstly, the magnitude of the correlation value between two fault modes is compared to determine the influence amplitude, and then all the influence amplitude values are summed up, and the value represents the influence fall between the fault modes. If 10, the value of the force related to 'tool can not be changed' is 0.023, and the value related to 'tool can not be changed' is 0, the problem of failure in the system, namely 'tool can not be changed', is compared with 'tool can be changed', and the influence range is 0.023-0 to 0.023; 11. stress or pressure, the "tool cannot be changed" is compared with the "tool fall", and the influence amplitude is 0.081-0.041-0.04; 12. the shape of the tool cannot be changed compared with the tool drop, and the influence range of the tool is 0.21-0.14-0.07; 21. the influence range of the power-incapable cutter changing is 0.098-0.065-0.033 compared with the power-losing cutter; the total influence amplitude of "not able to change knife" compared to "cut knife" in the system is 0.023+0.04+0.07+ 0.033-0.167, see the direct relation matrix Z.

Normalizing the direct correlation matrix to obtain a normalized direct correlation matrix:

finding the maximum value of the Z sum of the matrix

Dividing the matrix Z by this value yields the normalized direct correlation matrix X.

Establishing a comprehensive influence matrix according to the normalized direct correlation matrix:

computing

Converting a normalized direct correlation matrix into a synthetic impact matrix T

Then, the centrality (Q + D) and the causality (Q-D) are calculated:

assuming that the row and vector of the comprehensive influence matrix T are Q and the column sum vector is D, the sum of each column and each row of the comprehensive influence matrix is calculated according to the formula (2-3), and the obtained result is shown in Table 3.

TABLE 3 centrality and reason degree calculation table

Tab.3 Calculation table of center degree and cause degree

Finally, a cause and effect graph can be drawn according to the results:

and drawing a potential failure mode cause-and-effect graph by taking Q + D as an abscissa and Q-D as an ordinate respectively, as shown in FIG. 2. According to the reason degree, the main failure modes of abnormal tool changing, tool clamping, abnormal tool magazine running and tool falling belong to the main failure modes which need to be improved preferentially; according to the centrality, five fault modes of abnormal tool changing, tool clamping, damage of the hexagonal sleeve roller, abnormal tool magazine operation and tool falling are highly correlated with the fault of the tool magazine system, namely when the tool magazine system is in fault, the five fault modes of abnormal tool changing, tool clamping, damage of the hexagonal sleeve roller, abnormal tool magazine operation and tool falling are very likely to be the abnormal tool changing, the abnormal tool clamping, the abnormal tool magazine operation and the tool falling. Therefore, the five key failure modes of abnormal tool changing, tool clamping, damage of the hexagonal sleeve roller, abnormal tool magazine running and tool falling are adopted.

Then, based on a TRIZ analysis method, a contradiction matrix is established, a reliability improvement direction corresponding to the key fault mode in the contradiction matrix is extracted, and reliability improvement is carried out according to the reliability improvement direction.

There is a potential for adverse consequences due to the lack of FMECA to analyze the exacerbating effects that might be triggered by the improvement recommendations. Therefore, the research combines the contradiction matrix in the TRIZ theory, adopts the potential fault reason provided by FMECA as the item to be improved in the contradiction matrix, and then obtains the relatively deteriorated item through the contradiction matrix, and provides a suggested solution for improving the deteriorated item.

According to the above-mentioned critical failure modes: "abnormal cutter changing occurs", "cutter clamping", "damage of hexagonal sleeve roller", "abnormal operation of tool magazine" and "cutter falling", screening out relatively deteriorated items through TRIZ39 engineering parameters respectively, and finding out corresponding 40 inventive principles.

In 40 invention principles, a suitable invention principle is found for each key failure mode, and one or more are adopted as the direction for drawing up the improvement countermeasures by combining the respective situations, which is described as follows:

1) abnormality occurs in tool changing: the 'preaction' principle is adopted to check and adjust the air pressure condition, so that the abnormal cutter changing caused by the uncomfortable air pressure during cutter changing is avoided; by adopting the principle of 'pre-reaction', the ribbed plates are added at the part bearing the driving force to ensure the working reliability of the cutter head, realize the optimization of the rigidity of the cutter head and avoid the occurrence of the fracture fault of the cutter head; the principle of 'relieving in advance' is adopted, the cutter sleeve supporting wheel is replaced, the gap between the cutter sleeve supporting wheel and the body is adjusted, and the phenomenon that abnormal cutter changing occurs due to the fact that the gap is too large due to abrasion of the cutter sleeve supporting wheel is avoided.

2) Clamping a cutter: the expansion sleeve is replaced by adopting the principle of 'relieving in advance', so that the situation of locking failure is avoided; the principle of 'relieving in advance' is adopted, the coupling for connecting the motor shaft and the worm shaft is checked in advance, and fastening measures are taken to avoid the loosening phenomenon.

3) Damage of the hexagonal sleeve roller: the abrasion condition of the hexagonal sleeve roller is checked in advance by adopting the principle of 'relieving in advance', and the hexagonal sleeve roller is replaced in time.

4) Abnormal operation of the tool magazine: the wiring condition of the relay is checked by adopting a 'preaction' principle, so that the generation of a reverse connection condition is avoided; and (3) reinforcing the tool magazine bracket by adopting a 'pre-relaxation' principle.

5) Removing the cutter: and a 'pre-relaxation' principle is adopted, and fastening measures are taken for the magnetic induction switch so as to avoid the phenomenon of loosening of the magnetic induction switch.

In order to implement the method, the invention is programmed to implement the method by software, and a storage device is obtained, wherein a plurality of instructions are stored, and the instructions are loaded by a processor and execute the following processing:

Furthermore, the invention also provides a reliability improving device of the tool magazine system, which further comprises a processor for realizing each instruction on the basis of the storage device.

The invention constructs an analysis mode for improving the reliability of the tool magazine system through FMECA, DEMATEL and TRIZ theories, deduces a fault mode correlation matrix through the FMECA and the TRIZ theories, quantitatively analyzes potential fault modes through the DEMATEL, realizes classification and finds out key fault modes, and forms a new tool magazine system fault analysis mode capable of realizing classification;

by adopting the problem solving principle provided by the contradiction matrix table in the TRIZ theory, when measures are taken for a certain fault mode of the tool magazine system, the function deterioration of other fault modes can not be caused, the problem is really solved, and the defect of singly adopting FMECA in system deterioration analysis is overcome;

the above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of improving reliability of a tool magazine system, comprising:

step 2: establishing a contradiction matrix based on a TRIZ analysis method, extracting a reliability improvement direction corresponding to the key fault mode in the contradiction matrix, and improving the reliability according to the direction;

the step 1 comprises the following steps:

step 12: classifying the potential fault modes by adopting a DEMATEL analysis method, and extracting key fault modes;

the step 12 comprises:

establishing a correlation matrix of the potential fault mode and the project parameters of the TRIZ39, transforming the correlation matrix to obtain parameters for quantifying the grade of the potential fault mode, and extracting the potential fault mode represented by the parameters in a set range as a key fault mode;

the establishing of the correlation matrix of the potential fault modes and the project parameters of the TRIZ39 comprises the following steps:

the correlation between the TRIZ39 engineering parameters and each part of the tool magazine system is scored, and the weighted value of the TRIZ39 engineering parameters to each part of the tool magazine system is calculated according to the weighted value of each part of the tool magazine system;

2. The method of claim 1, wherein transforming the correlation matrix to obtain parameters for quantifying a potential failure mode level comprises:

3. The method of claim 1, wherein establishing the contradiction matrix based on the TRIZ analysis comprises:

4. The method of claim 3, wherein extracting reliability improvement directions in a contradiction matrix corresponding to the critical failure mode comprises:

5. The method of claim 3, wherein extracting reliability improvement directions in a contradiction matrix corresponding to the critical failure mode comprises:

and extracting various invention principles from the contradiction matrix, and formulating a fixed reliability improvement direction for solving the key fault mode by combining the various invention principles.

6. A memory device storing a plurality of instructions, the instructions being loaded by a processor and performing the following:

the step 1 comprises the following steps:

the step 12 comprises:

7. A reliability improving device of a tool magazine system comprises a processor, a control unit and a control unit, wherein the processor is used for realizing instructions; and storage means for storing a plurality of instructions, wherein the instructions are loaded by the processor and perform the following:

the step 1 comprises the following steps:

the step 12 comprises: