Disclosure of Invention
In order to solve the problems, the invention provides a system and a method for intelligently monitoring the service life of a cutter, which realize the full-chain type systematic management of cutter flow; the method predicts the residual life of the cutter by adopting the mode of processing the number of workpieces or accumulating the processing time which can be configured by an accumulation strategy, and then realizes the online monitoring visual management function which is more reliable, more scientific and more accurate in numerical value for the prediction result of the residual life of the cutter by utilizing the early warning value of the cutter life set by the system.
In order to achieve the purpose, the invention adopts the technical scheme that: an intelligent tool life monitoring system, comprising:
the workshop field layer is used for providing real-time field data for the system; arranging a data acquisition line on an on-site machine tool, acquiring the on-line cutter position and the cutter state of the machine tool in real time, and providing original data for visual management of cutter monitoring; the unit master control layer is used for realizing logic control among equipment in each unit of a workshop field layer, generally adopts a PLC (programmable logic controller) to carry out distributed control, and realizes information acquisition of bottom-layer equipment and information feedback of upper-layer equipment so that field personnel can know equipment state information, production management information, quality statistical information and the like in time; the workshop master control layer is used for realizing the scheduling of production tasks and the coordination control of equipment in the units, the issuing of the production tasks and the scheduling of the tasks according to priority, and simultaneously realizing the scheduling of agv trolleys in each processing unit and the path planning of the trolleys, and realizing the acquisition of field information and the visual monitoring of equipment state information, production management information, quality statistical information and the like; the visual management and control layer is a workshop execution system and is presented in a visual mode, so that enterprise managers can remotely check the production condition of the whole workshop, and the monitoring of the overall information of the workshop and the making of correct operation decisions are facilitated.
Further, the equipment of the workshop field layer comprises a flexible processing unit, an agv material transportation trolley, a material storage unit, a tool storage unit and the like.
Further, the system meets network connection of devices with different protocols, and cutter life early warning of a heterogeneous numerical control network is achieved, for example, a Siemens numerical control system adopting OPC UA, a Sendai adopting FOCAS communication protocol, a numerical control system adopting ethercat protocol i5 and the like.
Further, the visual management and control layer represents various information in a modular form, wherein the information comprises production management information, quality management information, equipment management information, process information, material management information and the like.
The invention also provides an intelligent monitoring method for the service life of the cutter, which comprises the following steps:
step 1: tool information digitization
The geometric information, the splicing information, the cutting parameters, the process information, the service life of the cutter and other information of the cutter are digitally described;
step 2: setting of monitoring terminal and numerical control system
(1) Setting of monitoring terminal
The monitoring end needs to be set as follows:
1) for applying for general material setting of cutter
Selecting a general material menu to create a material blank, inputting a material number, selecting a process type from material types, and storing the information;
2) setting of new tools
Selecting a cutter maintenance menu in cutter management software, executing operation of the newly added cutter, and filling the serial number, sister cutter information, cutter geometric parameter information and cutter service life early warning value of the newly added cutter; determining a tool life early warning value by adopting a statistical analysis method in combination with historical tool life information; assuming that the tool life follows a normal distribution, i.e.
(ii) a Solving parameters using maximum likelihood estimation
、
A value of (d); likelihood function
Comprises the following steps:
in the formula:
the number of samples;
simplifying to obtain:
the normal distribution probability density function of the wear life is as follows:
the distribution function of tool life is:
the tool life calculation satisfying the reliability is that the reliability of the tool is set as
Calculating a tool life early warning value according to the allowable reliability;
3) product processing technology setting
Selecting a process data menu, setting a machining process, inputting process parameters including cutting diameter, spindle rotating speed, cutting depth and feeding speed, and binding a cutter and materials;
4) tool life monitoring function
Selecting a tool life menu, monitoring the life of the tool, and determining the type code of the tool used by each machine tool according to the machining process; if the tool display is green, indicating that the tool life is normal; if the cutter display is yellow, the cutter service life is indicated to reach an early warning value, and the cutter is reminded to be replaced; if the cutter display is red, the service life of the cutter is indicated to reach an alarm value, and the cutter is replaced;
(2) setting of numerical control system
The set and program flow is as follows: opening a tool life management function page and selecting a tool life calculation mode (frequency); setting the theoretical life of the cutter and clearing the actual life on a cutter deviation-cutter life page; inputting TLIFE _ M in the program; fourthly, the service life of the cutter is counted by M30\ M02\ M90; running a corresponding cutter measuring program in the program; when the cutter reaches the service life, the system gives a prompt that the cutter has reached the service life.
The following codes are added into an automatic line processing program:
G54
T2M6
T3
M3S3200F400
TLIFE _ M; tool set life start
G0G90X0Y0Z50
MCALL CYCLE83 (50,0,3,-19,19,0,3,3,2,1,1,0)
HOLES2(0,0,37,30,60,6)
MCALL
G0Z71.185
X0Y200
M90; tool set life count
M5
And step 3: calculation of tool life loss
Relevant parameters in the step 1 cutter life management module are a life set value, a life early warning value and a life remaining value; the timing management takes minutes as the unit of the service life of the blade, the service life set value is the maximum accumulated processing time of the blade, and when a cutter is newly built, the residual service life value of the blade is equal to the service life set value;
step 2, in the processing process, the numerical control system updates the residual life value and subtracts 1 from the residual life value every other minute;
whether step 3 reaches the time interval of tool detection, if not, step4 is switched, if yes, the tool wear amount is detected, and the detected tool wear amount is taken as:
taking the maximum value as the current abrasion loss of the cutter position:
calculating the current tool life:
in the formula (I), the compound is shown in the specification,
is the maximum wear alarm value of the cutter,
is an ideal life value of the cutter
Correcting the service life of the cutter: judgment of
If the current tool life timing value is greater than the current tool life timing value, setting the current tool life as the current tool life timing value
;
step4, judging whether the remaining value of the service life of the current blade is equal to the lower limit of the service life of the blade, if the remaining value of the service life of the current blade is equal to the lower limit of the service life of the blade, updating the state of the current blade to be a service life early warning value by the cutter management module, and triggering PLC to give an alarm;
step 5, when the remaining life value is reduced to 0, the state of the cutting edge is updated to be 'end of life', the PLC gives an alarm, and the current cutting edge of the cutter is forbidden.
The invention has the following beneficial effects:
1) has the characteristic of intellectualization. The invention considers the management of the whole life cycle information of the cutter, comprehensively masters the management information of the cutter and has the traceability of historical information;
2) the reliability is high. The existing method for predicting the residual service life of the cutter mainly uses the number of machined workpieces, is only suitable for an ideal machining environment and cannot be dynamically adjusted according to actual conditions, and the method provided by the invention meets the dynamic adjustment of users.
Detailed Description
In order that the objects and advantages of the invention will be more clearly understood, the invention is further described in detail below with reference to examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
As shown in fig. 1, an intelligent monitoring system for tool life according to an embodiment of the present invention includes:
(1) and the workshop field layer is used for providing real-time field data for the system. The equipment of the workshop field layer comprises a flexible processing unit, an agv material transportation trolley, a material storage unit, a tool storage unit and the like. A data acquisition line is arranged on the on-site machine tool, the on-line tool position and the tool state of the machine tool are acquired in real time, and original data are provided for visual management of tool monitoring. The invention meets the network connection of devices with different protocols, realizes the cutter service life early warning of a heterogeneous numerical control network, such as a Siemens numerical control system adopting OPC UA, a Sendai adopting FOCAS communication protocol, a numerical control system adopting ethercat protocol i5 and the like;
(2) the unit main control layer is used for realizing logic control among equipment in each unit of a workshop field layer, usually adopts a PLC (programmable logic controller) to carry out distributed control, and realizes information acquisition of bottom-layer equipment and information feedback of upper-layer equipment so that field personnel can know equipment state information, production management information, quality statistical information and the like in time;
(3) the workshop master control layer is used for realizing the scheduling of production tasks and the coordination control of equipment in the units, realizing the issuing of the production tasks and the scheduling of the tasks according to priority, simultaneously realizing the scheduling of agv trolleys in each processing unit and the path planning of the trolleys, and realizing the acquisition of field information and the visual monitoring of equipment state information, production management information, quality statistical information and the like;
(4) the visual management and control layer is a workshop execution system and is presented in a visual mode, so that enterprise managers can remotely check the production condition of the whole workshop, and the monitoring of the overall information of the workshop and the making of correct operation decisions are facilitated. The layer represents various information in a modular form, including production management information, quality management information, tool detection information, process information, material management information, and the like.
Fig. 2 shows a tool management flow of this embodiment. The management process is mainly characterized in that:
(1) the method aims at the full-chain type systematic management of the 'cutter flow'. The content of the management information covers the whole life cycle information from the registration of the cutter to the scrapping of the cutter, so that on one hand, the processing information is convenient to trace; on the other hand, the accurate prediction of the service life of the cutter is convenient to realize;
(2) and flexibly configuring the service life early warning value of the cutter according to actual requirements. According to different actual requirements, the method for determining the service life early warning value of the cutter is different. When batch processing or processing contents are fixed, the processing times adopting static configuration are more reasonable; and for the task processing with large processing content change, the processing time is reasonable. Aiming at the determination of the early warning value of the service life of the dynamic cutter, scholars at home and abroad have obtained certain research results, and a corresponding model is established for the distribution of the service life of the cutter. The system provides an open development interface for developing a corresponding algorithm module so as to ensure the accuracy of the calculation of the service life of the cutter;
(3) and adopting the abnormal detection of the cutter as the judgment basis for monitoring the residual service life of the cutter. The processing content of the cutter breaking detection is added in the flow, the machine tool adopts a cutter instrument to detect every certain processing time or processing part number, and if the size of the cutter exceeds a specified range, the cutter can not be used continuously.
As shown in fig. 3, the present invention further provides an intelligent monitoring system for tool life, comprising the following steps:
step 1: tool information digitization
In order to realize management of the cutter information, firstly, the geometric information, the assembly information, the cutting parameters, the process information, the service life of the cutter and other information of the cutter need to be digitally described.
Step 2: setting of monitoring terminal and numerical control system
(1) Setting of monitoring terminal
The monitoring end needs to be set as follows:
1) for applying for general material setting of cutter
Selecting a general material menu to newly create a material blank, inputting a material number, selecting a process category from the material categories, and storing the information. As shown in fig. 4.
2) Setting of new tools
In the tool management software, a tool maintenance menu is selected, the operation of newly added tools is executed, and the number of the newly added tools, sister knife information, tool geometric parameter information, tool service life early warning values and the like are filled. As shown in fig. 5.
And determining a tool life early warning value by adopting a statistical analysis method in combination with historical tool life information.
Assuming that the tool life follows a normal distribution, i.e.
。
Solving parameters using maximum likelihood estimation
、
The value of (c).
Likelihood function
Comprises the following steps:
in the formula:
the number of samples;
simplifying to obtain:
the normal distribution probability density function of the wear life is as follows:
the distribution function of tool life is:
the tool life calculation satisfying the reliability is that the reliability of the tool is set as
And calculating the early warning value of the service life of the cutter according to the allowable reliability.
3) Product processing technology setting
Selecting a process data menu, setting a machining process, inputting process parameters including cutting diameter, spindle rotating speed, cutting depth and feeding speed, and binding a cutter and materials. As shown in fig. 6.
4) Tool life monitoring function
The tool life menu is selected to monitor the tool life. And determining the type code of the cutter used by each machine tool according to the machining process. If the tool display is green, indicating that the tool life is normal; if the cutter display is yellow, the cutter life is indicated to reach the early warning value, and the cutter is reminded to be replaced. If the tool display is red, the tool life is indicated to reach the alarm value, and the tool is replaced.
(2) Setting of numerical control system
The set and program flow is as follows: opening a tool life management function page and selecting a tool life calculation mode (frequency); setting the theoretical life of the cutter and clearing the actual life on a cutter deviation-cutter life page; inputting TLIFE _ M in the program; fourthly, the service life of the cutter is counted by M30\ M02\ M90; running a corresponding cutter measuring program in the program; when the cutter reaches the service life, the system gives a prompt that the cutter has reached the service life. The following codes are added into an automatic line processing program:
G54
T2M6
T3
M3S3200F400
TLIFE _ M; tool set life start
G0G90X0Y0Z50
MCALL CYCLE83 (50,0,3,-19,19,0,3,3,2,1,1,0)
HOLES2(0,0,37,30,60,6)
MCALL
G0Z71.185
X0Y200
M90; tool set life count
M5
And step 3: calculation of tool life loss
The tool life loss calculation is divided into two modes of timing and piece counting, and since the two modes have the same principle, the following description is collectively expressed in a life timing mode.
Relevant parameters in the step 1 cutter service life management module are a service life set value, a service life early warning value and a service life remaining value. The timing management takes minutes as the unit of the service life of the blade, the service life set value is the maximum accumulated processing time of the blade, and when a cutter is newly built, the residual service life value of the blade is equal to the service life set value.
step 2 during the process, the numerical control system updates the life remaining value by 1 every minute.
Whether step 3 reaches the time interval of tool detection, if not, step4 is switched, if yes, the tool wear amount is detected, and the detected tool wear amount is taken as:
taking the maximum value as the current abrasion loss of the cutter position:
calculating the current tool life:
in the formula (I), the compound is shown in the specification,
is the maximum wear alarm value of the cutter,
is an ideal life value of the cutter
Correcting the service life of the cutter: judgment of
If the current tool life timing value is greater than the current tool life timing value, setting the current tool life as the current tool life timing value
。
step4 judges whether the remaining value of the service life of the current blade is equal to the lower limit of the service life of the blade, if the lower limit of the service life time of the blade is reached, the cutter management module updates the state of the current blade to be a service life early warning value, and triggers PLC alarm.
step 5, when the remaining life value is reduced to 0, the state of the cutting edge is updated to be 'end of life', the PLC gives an alarm, and the current cutting edge of the cutter is forbidden. The tool life intelligent monitoring system is applied to a digital factory project, and a tool remaining life monitoring effect graph is shown in an attached figure 7. The system realizes the service life monitoring of each cutter of the flexible processing unit, wherein numerical control systems adopted by each processing unit are respectively an i5 numerical control system, a Seneko numerical control system, a Siemens numerical control system and the like. The practical processing verification shows that the monitoring system has the effectiveness and the reliability of monitoring the service life of the cutter, and the service performance of the cutter is exerted to the maximum extent, so that the production cost of a digital factory is obviously reduced, and the monitoring system has certain popularization and application values.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be construed as the protection scope of the present invention.