Computer Integrated Manufacturing Systems 1994 7(4) 269-278 Design for automating the inspection of manufacturing parts Michael D Reimann and Joseph Sarkis College of Business Administration, The University of Texas at Arlington, Information Systems and Management Sciences, Box 19437, Arlington, TX 76019~9437, USA The integration of quality into management of advanced manufacturing systems has not typically included automated approaches. With the advent of automated inspection and quality tools such as coordinate measuring machines and other dimensional measuring equipment, the linkage with integrated manufacturing systems seems natural. This paper shows the functional relationship of computer aided process planning to automated inspection process planning. The series of functional activities within each of these frameworks are mapped in this paper. The operational environment to include computer aided quality control in an integrated manufacturing system is also defined. Keywords: automated quality control, CAPP, quality information systems, inspection process planning Introduction Computer aided process planning (CAPP) is used in computer integrated manufacturing (CIM) environments to automate the linkage between the design and manufacturing phases of product development. A general approach for CAPP developed by the Consortium for Advanced Manufacturing - International (CAM-I) is described in this paper. The CAMI Advanced Numerical Control (ANC)' processor specifies the structure and defines the functions necessary for automating the process planning of machined parismatic parts. The ANC processor also provides the foundation for developing an architecture for automating of inspection process planning. First, the overall structure and functional components of the ANC processor are described. The next section delineates a comparable framework for automating inspection process planning. The framework for automated inspection process planning is compared to the ANC processor. External components required for the inspection process planning framework are presented. The final section summarizes the main issues identified in this paper and draws conclusions relative to practical implementations. The ANC processor The objective of the Advanced Numerical Control (ANC) processor is to automatically generate the necessary numerical control (NC) instruction sequence and supporting information for producing a finished part. In theory, all that should be required from the ANC user would be the identification of a part which exists in an external part model database. From the part definition, a complete process plan to machine a finished part is derived for the removal of volume from an initial raw stock. Thus, the ANC processor is intended to: • provide a structure which facilitates automation of NC processing functions, • bring order to the NC planning and programming function, • provide user-friendly tools for ANC functions which are not fully automated. The structure and functional components of the ANC processor are illustrated by the IDEF0 model shown in Figure 1. Each of the functions in this framework will be described in the remainder of this section. Obtain operation from the process plan This function obtains basic information about a machined part from the ANC user. Data that is requested from the user by this function includes: • identification of the part model before NC machine operation, • identification of the part model after NC machine operation, • specification of a NC machine tool to be used (optional). This information is used by subsequent functions in the ANC processor. The part identification numbers are used by the Material Decomposition function to 0951-5240/94/04/0269-10 (~) 1994 Butterworth-Heinemann Ltd 269 , a~qtanN Z ~utnl°A su2ats,~S ~u~..tntooJnut~lq paw.ta~tUl .talnazao,9 OL~ ~a t G ' li~-- ~ ,=,1 Z i:-J0 i P~ |. i i a iIT-~ Modifications from N C P ] m R e v i e ~ ~~ q~lavS f p u v uumul.a~t G l q :slaDa p d a m o v j n u m u j o uol.loaasu~, attl a u l . m t u o m v Automating the inspection of manufactured parts: M D Reimann and J Sarkis retrieve various geometric models of the part and determine delta volumes necessary to produce intermediate and final part shapes. Identification of the NC machine tool is conveyed to the Machine Tool and NC Tactics function, where it is used to determine machine tool characteristics and select an appropriate machine tool. Decompose material to be removed Basic operational process plan information is generated by this function to establish models and delta volumes for intermediate part geometries. The technique of volume decomposition is employed to remove individual (delta) volumes of material from a model of stock material to produce an intermediate or final part model. The Material Decomposition function uses 'before' and 'after' part model geometries which are made available to the ANC processor from an external part design database. The raw stock, from which the part is produced, is not modelled in the geometric part database. Specification for raw stock must be obtained from a Stock Definition library, which is external to the ANC. Various volume decomposition algorithms may be used by this function. These algorithms are also external to the ANC processor. Geometric models for the delta volume geometries are developed by an external geometric modeller. As subsequent operations are performed in the ANC processor, adjustments in the results developed by this function may be needed. These requests for modifications are fed back as inputs to the Material Decomposition function as they occur. Determine machine tool and NC methods In this function an appropriate machine tool and NC method to remove each delta volume is determined. A simplifying assumption made for this function is that only one machine tool may be used for machining of the part. The machine tool can be optionally specified by the user when the model was initially identified. If the machine tool is predetermined, suitable NC methods for each delta volume are established by this function. When the machine tool is not pre-specified by the user, this function will first determine an appropriate NC method for each delta volume. Once the NC methods for all delta volumes are established, the most suitable machine tool is then selected. The design for this function allows for either a manual or automatic mode for establishing machine tool and NC methods for the part machining process. This could potentially require the user to examine and assign NC methods for every delta volume. An intelligent decision tool would be needed to automate the decision process for determining an appropriate machine tool and NC methods. Such a decision aid would be external to the ANC processor. Subsequent ANC processor operations may require adjustments to the results developed by this function. These requests for modifications are fed back as inputs to this Machine Tool and NC Methods function as they occur. Determine setup The necessary setup characteristics for the part machining process are established by this function. Some of the specific issues that are addressed by this function include: • Orientation of the Part Information from the previous functions is used to develop appropriate orientations for the part. Models of the part geometries are obtained by the Material Decomposition function. These models are used to determine the physical characteristics of the part that influence fixturing and clamping of the part. Constraints imposed by physical characteristics of the part, the NC methods employed and the selected machine tool are used to determine suitable part orientations. A geometric modeller is used to construct orientations for the part, from which desired features can be machined. These orientations are compared to machine tool capabilities to ensure compatibility with the machine tool. • Fixture design The geometry of the part, delta volume removal requirements and part orientation are used to choose appropriate fixtures for holding the part. Features of the machined part are compared with the fixture feature capabilities of available fixtures. Based on this comparison, a suitable fixture is selected. • Clamp design and selection Clamp design and selection uses part orientation and fixture information to choose clamps for holding the part. Candidate surfaces for clamping are compared to clamps defined in a clamp table. Clamp selection can be performed manually or by an automated decision process. Clamp selection data is fed back to the fixture design sub-function to ensure compatibility between fixture and clamp selection. • Setup evaluation All support information and determinations made up to this time are presented to the user for review and modification. Information that can be reviewed includes: intermediate geometric part models - NC methods machine tool identification part orientation fixturing - clamping. - - - - Based on this review, the user can initiate modifications to previously obtained results. Determine cutting tool and homer This function establishes the appropriate sub-delta material volumes, suitable cutting tool and cutting tool holder for the removal of each sub-delta volume. Delta volumes are used to define the required volume to be Computer Integrated Manufacturing Systems Volume 7 Number 4 271 Automating the inspection o f manufactured parts: M D Reimann and J Sarkis removed from a 'before' part model to produce a feature on an 'after' part model. The actual types of machining steps (work elements) are defined by a specific NC method. Based on the total delta volume and the corresponding NC method, sub-delta volumes for each work element are established. Information obtained from previous ANC processor functions which are used by this function includes: • • • • individual delta volumes NC methods for producing the delta volumes manufacturing parameters and standards machine tool setup data. Cutting tool selection requires sub-delta volume and NC method information to choose appropriate cutting tools for removing each desired sub-delta volume. Available cutting tools are specified in a cutting tool library. Individual cutting tools are compared against each required sub-delta volume to make a choice. Tool holder selection uses setup and cutting tool information to choose the holder. The cutting tool and machine tool are compared with available holders. Compatibility must exist between the machine tool, cutting tool and cutting tool holder to result in a holder selection. Special tool holders may be supported by this function. Feedback from the NC Plan Review and Tool Path Simulation function may necessitate adjustments in this function. Detail~optimize N C p l a n The preparation of the detailed NC plan is carried out by this function. Many of the previously determined NC production characteristics are used by this function to carry out its objective. This information may include: • individual delta volumes for material removal from the before part model to produce the after part model; • corresponding NC methods required to remove the delta volumes to produce the desired features; • machine tool identification; • part orientations, fixture and clamp specifications; • sub-delta removal volumes; • cutting tool and holder specifications. This function is comprised of the following subfunctions: o f strategy Identifies the overall strategy the NC process will employ to produce the part. Possible strategies may include the minimization of tool path travel lengths, minimization of the number of fixture changes, minimization of the number of part re-orientations, or minimization of the number of cutting tool and holder changes. A number of decision steps are performed to determine the most appropriate strategy to be used by the NC Plan Generation sub-function. 1. Identification 272 Computer Integrated Manufacturing Systems Volume 7 Number 4 2. N C plan generation The chosen strategy is used to sequence the work elements in the NC plan. Information provided about each work element to this sub-function includes setup data, NC method, cutting tool and cutting tool holder specifications. The result produced by this sub-function is a NC plan within which work elements have been ordered based on a designated hierarchy of strategies. 3. N C tactics The ANC user may review each work element in the NC plan through graphical techniques. NC tactics for the removal of sub-delta volumes can be altered by the ANC user through direct interaction with the system. Seven stages are associated with each NC tactic: • A p p r o a c h - movement from a clearance plane to an operative geometric position. • Enstage - movement from an operative geometric position to initial contact with part material. • E n t r y - movement from an initial part material contact to full part material contact. • M a c h i n i n g - movement through the continuous engagement with part material. - movement away from full part material contact to exit from material. • Destage - movement away from final contact with part material to an operative geometric position. • Retract - movement from an operative geometric position to a clearance plane. • Departure The ANC user accesses the geometric modeller to determine the cutting tool movements. A tactics table, which includes coordinate points and other pertinent machine tool process information, is developed by this sub-function. 4. R e v i e w o f N C p l a n Once the NC plan and associated tactics have been determined, the user can review the part generations with the graphical interface. The geometric modeller can be used to display the position of the cutting tool and holder as they move in relation to the stationary part. Detection of proper coverage and collision avoidance can be observed with the NC Plan Review sub-function. In addition, interference with fixtures and clamps may be examined. Because this sub-function can detect conflict situations, it will produce feedback to previously executed functions in order to rectify any problems. Generate~simulate tool path The objective of this function is to generate tool path commands for each NC work element. Tactics records from the NC plan are used as an input to this function. Tactics specify the NC steps and characteristics which are necessary to produce the sub-delta volumes. Information in the tactics record is formatted for internal use by the ANC processor. A tool path generator sub-function converts a two-dimensional representation into a three-dimensional parametric equivalent. Graphical simulation of this approach enables the user view the tool path motion. The Automating the inspection of manufactured parts: M D Reimann and J Sarkis simulation uses the geometric modeller to produce the visual images. Produce machine control information This function generates the appropriate Cutter Language (CL) instructions which will be used by a NC machine tool to machine the part. The tool part information that was generated in the previous function is converted into compatible CL data. This translation may use various techniques that exist in the research literature, many of which utilize various forms of expert systems. Once these basic instructions are determined, graphical simulation will be used to represent the NC machining process. The generic CL instructions are then translated to machine dependent NC code. Produce support information The last function simply provides a user-friendly interface, for the machine tool operator, to obtain information from the ANC processor. Components of this function include: • generation of operator instructions • visual aids • material orders. The finalized NC plan and associated tactics form the basis for information that is presented to the operator. This information is translated from an internal representation to an operator understandable form. A N C research issues A number of research opportunities can be identified in the ANC processor. Many of the functions which comprise this framework rely on some form of selection and sequencing decision process. Appropriate tools presently exist that would address many of these decision processes from an automation perspective. Special algorithms and heuristics can be tested to determine which would be most efficient. Additional research opportunities exist in regard to optimization of these decisions. This area is fertile for further development of each of the ANC steps, as well as applying these generic stages to various automated planning for machining, assembly, inspection and material handling processes. How the ANC process functions can be utilized to develop the instructions and plans for an automated inspection process planning system are described in the next section. Automated inspection process planning framework using advanced numerical control concepts The ANC processor provides a general framework for the automated development of process plans for numerically controlled machining equipment. This framework can be used as a foundation to automate other processes within a CIM environment. Competition in manufacturing environments is increasingly becoming time-based. To improve competitive posture, many organizations are adopting a total quality orientation. Automation of quality functions in a CIM environment is an integral component in philosophies such as total quality management (TQM) and quality function deployment (QFD). Research in integrating automated inspection equipment, such as dimensional measuring equipment (DME) or coordinate measuring machines (CMM), with other components of CIM has received limited attention until recently2m. This section serves two purposes. First, it demonstrates that the ANC framework is generalizable and can be used to develop other components in a CIM environment. It also describes a framework which is oriented towards quality functions and part inspection. This framework is referred to as the Expert Programming System-One (EPS-1) processor 7. As we shall see in a later section, the EPS-1 is part of a larger operational environment that integrates inspection process planning with the remaining components of a CIM system. EPS-I architecture The EPS-1 is a functional subset of the ANC processor. As such, the EPS-1 embodies many of the same characteristics as the ANC. Certain characteristics that are part of the ANC are not required in the EPS-1 framework. Only the differences between ANC and EPS-1 processors will be described in this paper. The main differences are primarily due to the underlying purpose of each processing framework. Whereas the ANC processor is primarily for machining purposes, the EPS-1 architecture is not a material transformation process, but an inspection process. Thus, many of the data and tool characteristics in the EPS-I environment do not require material removal that are characteristic of the ANC processor. The EPS-1 requires a part identification number and an overall process plan as inputs. The identification number is used to retrieve a geometric model and a dimensioning and tolerance model of a part. The DME NC plan generator uses the overall plan to produce dimensional measuring interface specification (DMIS) control data and support information for a specific DME. Figure 2 shows the relationships among nine functional modules that form the EPS-1 architecture. The remainder of this section describes each of these nine functional modules. Obtain operation plan The EPS-1 user provides required data to the EPS-1 for initiating the automated inspection process. This function determines the scope of the inspection process to be performed on the indicated part. Data needed by the EPS-1 includes: • a valid part identification number • an inspection type Computer Integrated Manufacturing Systems Volume 7 Number 4 273 ,.,.1 ~.¢ Idcmdficafion Inmp¢~io~Type I DME C l ~ V l l ~ h i m ~ 3" Mo~r I ~"~ Datglwe Inter.MachiKLibruyDME D'a",,,l~ee I T"'¢" I e~ II Deeompo~itionT 1A'211 Featut~ 1 c~ I NC Medaod~ Module t 11 Operato~ In~etio~s 111 .. ,q .~~, 4~ 11 i _ , ,~o,,..o. I .o. T1 Probe Holde~ Module Module iI Ope~tionPI~.6 DME NC Plans wilh Tactic~ 1 MachineTool IX.pmdmtCon~oKs) ProbeP~hA.? I ProbePath ~ I D ' Module r Gel~elzic t 11 l~w*merric Probe ] Produce Con~l ] PareC,~m'ator Ii I li~os'mliou A.8 DMlS Co~rol D~* I DMIS D m lvll~c~i~ I Produce Support ] Formatter Co~a,ol ] Module hafoemstiou Vi~d Aim A.9I o,l-o VisualAid Gee.mot Figure 2 High level IDEF0 diagram for EPS-I framwork IC • IT ,p~ m . Automating the inspection of manufactured parts: M D Reimann and J Sarkis • a D M E class or machine (operational) • an inspection strategy (optional). The inspection type establishes the scope of the inspection operation (i.e. courtesy inspection, inprocess inspection, final inspection, etc.). The part identification number and the scope of the operation are used to determine the correct model in the geometric model database and the corresponding model in the D & T database. The output from this function includes work element identifiers that are passed on to the Task Decomposition function, and the type of D M E to be utilized, which is used by the Determine NC Methods and D M E function. The EPS-1 must obtain the scope of the D M E operation from the EPS-1 user, whereas the A N C obtained a machining process plan. Because the EPS-1 does not remove material from a part, it only requires the identification of a single part model. On the other hand, the A N C process requires the existence of before and after part models. Task decomposition The Task Decomposition function determines the evaluated dimension and tolerance ( E D T ) features that are to be measured by the inspection process. The EPS-1 automatically determines these from information obtained by the Obtain Operational Plan function. The part identification and the inspection type uniquely identify the geometric and D & T models of the part. An entire D & T model is obtained through subroutine calls to the D & T modeler. The D & T model is used by the Task Decomposition function to construct a skeletal list of the work elements necessary to perform the inspection process. For each node in the D & T database, an individual work element item is constructed. Subsequent functions in the EPS-1 use this information to determine other inspection process requirements and characteristics. The EPS-1 only requires one part model identification, and there is no product transformation feedback required. The output data representations also vary, whereas the EPS-1 data is a list of E D T features for the part to be inspected, the A N C outputs geometric models of the current state of the part and derived delta volumes. Another major difference is the lack of the need for a raw stock model in the EPS-I. process initialization, selection of a D M E will be bypassed. In this case, the NC measurement methods required for the inspection process are compared with those available from the specified D M E , to ensure that the D M E is capable of taking the required measurements. If a D M E was not specified, then the EPS-1 compares the capabilities of available D M E against the NC measurement methods required for the inspection process in order to choose a DME. The requirements for the ANC and EPS-1 processors are similar for this function. Different methods of obtaining and transforming data are required, since the characteristics of the equipment in each of the processes will utilize different internal representations of the data. Determine setup Part setup generally applies to the part orientation and fixture and clamp selection in a NC environment. To simplify the complexity of this process, fixtures and clamps were not incorporated into the initial specification of the EPS-I. Part orientation is accomplished by alignment of part surface normals with the D M E measurement axes. Three potentially conflicting objectives are considered: • maximize the number of measurements in any given orientation • minimize the number of orientations to achieve the required inspections • eliminate possible collisions between the D M E and the part due to improper orientation. The above strategy requires the geometric modeiler to perform boolean algebra intersections on the part and probe models so as to detect potential collisions. In the initial version of EPS-1, fixtures and clamps are not required. Fixtures and clamps must be used in the A N C environment. Determine probe~holder Combinations of measurement probes and holders for the inspection process are determined by this function. Selection of a probe can become a complex task when the following factors are taken into consideration: Determine methods and D M E • • • • D M E technologies probe relative orientation multiple probe setups probe shape. This function serves two purposes: first, it determines the appropriate NC measurement methods for the inspection process; then it identifies the most appropriate D M E for taking the actual measurements. For the purposes of the EPS-1, the combination of tolerance class and sub-feature class is used to establish individual NC measurement methods. Once the methods have been determined, a D M E machine can be chosen. If a D M E machine was specified during Due to this complexity, candidate probes must be identified through a process of elimination. The capabilities of the available probes are compared to required measurement characteristics of the inspection process. A probe is determined for each sub-feature on the part. Several probes may be required to measure the entire part. The strategy at this point may be to select probes based on minimizing the number of probes for the entire inspection process. A n o t h e r probe Computer Integrated Manufacturing Systems Volume 7 Number 4 275 Automating the inspection of manufactured parts: M D Reimann and J Sarkis selection strategy might be to maximize the number of measurements obtained from the individual probes. There are four basic differences between ANC and EPS-1 processors relative to this function: • The ANC sub-delta volume generator is replaced by the EDT sub-feature generator in the EPS-1. • The EPS-1 design does not require the user to supply manufacturing parameters. • The EPS-1 must select an appropriate probe instead of a cutting tool. • The EPS-1 does not determine a probe holder. Detail~optimize operation plan Inspection process information that was developed by previous functions is used by this function to complete the operation plan. The EPS-1 finalizes the sequence of work elements and determines the corresponding movement tactics for the inspection process. Three activities are performed by this function: • NC plan generation • determination of NC tactics • review and modification of the NC plan. Sequencing of the individual work element items is determined by this function. The NC strategy previously specified by the user forms the basis for the ordering process. On the basis of this strategy, an appropriate set of logic is used to establish the specific sequencing of the work elements. The types of logic used depends on the sequencing strategy. Mixtures of heuristic, optimizing and decision table logic may be employed. Relative positioning of the probe is also determined for every sub-feature measurement to be made. All the processing up to this point has been automatically carried out by the EPS-1. The work elements, NC plan and NC tactics are now complete, and the user can intervene to make any adjustments. The user may review a graphical representation of the inspection process sequence. This will indicate potential coverage and collision problems. The user can make the necessary corrections to eliminate any problems. Simple changes can be made by the user without any further intervention by the EPS-1. The primary difference between the ANC and EPS-1 processors, for this function, is in the internal representation of the data and the decision making approach employed. These will differ due to the need for more data items in the ANC processor. Generate~simulate probe path This function serves two purposes: to generate locational and parametric probe path data; and to visually simulate that data. The primary input to this function is the NC plan with tactics, and the primary output is an internal representation of the probe path data. The NC plan with tactics contains an ordered list of the work elements required to inspect the identified EDT features. The work elements are processed 276 ComputerIntegrated Manufacturing Systems Volume 7 Number 4 sequentially, and contain the sub-feature mean, the sub-features class "and the tolerance class for each entry. The measurement process involves the generation of initial and departing probe positions and parametric probe path motion. Positioning of the probe for measurement is determined by generic routines that are geometry-specific. EDT sub-feature class/tolerance class combinations dictate the appropriate routine. The routines use specific D&T information to establish actual probe position. The parametric probe path data is mathematically determined for each measurement. The probe path data is composed of two curves that are parametrically synchronized. One of the curves represents the probe end, while the other represents the probe axis. Once the parametric probe path is created, it is used to graphically illustrate the movement of the probe in relation to the stationary part. The user can review the movements of the probe over the part to observe coverage and detect collisions. The type of algorithms required by the ANC and EPS-1 processors for this function will necessarily have to differ. For example, there will need to be a greater diversity in the path patterns that are required for machining when compared to measurement operations. Generation of the probe path for taking dimensional measurements will incorporate different characteristics from that of a cutter tool path. Produce control information Numerically controlled DME inspection instructions are generated by this function. These instructions conform to the dimensional measuring interface specification (DMIS) 8. The NC plan with tactics provides the necessary tolerancing information. The coordinates of the actual points for every movement and measurement are retrieved from an internal representation of the probe path. All of this information is combined to produce DMIS instructions. This function also allows DME independent control information to be interspersed with the DMIS instructions. The main difference in this function between the ANC and EPS-1 processors is the type of output data. DMIS data will be output by the EPS-1, while APT compatible CL data will be output by the ANC processor. Produce support information Information that supports the actual NC inspection operation is developed by this function. It is defined in such a way that it can be tailored to support the specific environment of an individual implementation. Information for a DME operator is generated, as well as for other users indirectly involved in the NC inspection operations. These individuals may include quality assurance engineers, shop supervisors, foremen or tool crib operators. The main difference between the ANC and EPS-1 Automating the inspection of manufactured parts: M D Reimann and J Sarkis ances for the geometric features of a part 1°. Many existing geometric modellers do not have the capability to produce the dimensioning and tolerancing information that is needed by inspection applications. Thus, a Dimension and Tolerancing (D&T) modeller 11 was designed and developed to fill this void. The D&T modeller defines various tolerance nodes, and assigns these nodes to one or more geometric features. After geometric features have been added to a part model, the D&T modeller must be used to augment the geometries with specific dimensioning and tolerancing data. processors for this function is that the EPS-1 will generate less support information. Operational environment of the EPS-I The EPS-I interacts with various external components, as shown in Figure 3. The main components in this operational environment include a geometric modeller, the Dimensioning and Tolerancing (D&T) modeller, the Applications Interface Specification (AIS), the Dimensioning and Tolerancing Applications Interface Specification (DTAIS), the Dimensional Measuring Interface Specification (DMIS), and support databases. All of these components play an integral role in the EPS-1 framework, either as inputs, controls or mechanisms for processing. Each of these components will be described in the remainder of this section. Applications interface specification Due to unique capabilities that are offered by various geometric modellers, an inspection application may require the use of several modellers. To avoid the necessity for developing unique interfaces for each combination of application and modeller, a standard interface similar to IGES has been developed. The Geometric Modeling Program of CAM-I has defined the application interface specification (AIS) to satisfy this need. The AIS is a dynamic interface between modellers and applications software. Modeilers and applications that have been designed and implemented to conform to the AIS can interface directly with one another. The AIS defines a core set of capabilities that should be available from any geometric modeller. If a particular modeller has the capability to perform a specific function, then the interface acts only as a communications media. On the other hand, when the function is not supported by a modeiler, the application interface would be required to perform that function. Geometric modeller A geometric modeller is used to delineate, identify and define the physical characteristics of a part. Various geometric entities can be described by their boundaries. The geometric modeller facilitates certain functions that are specific in inspection. In particular, collision between probe and part can be detected by performing a boolean intersection on geometric models of the part and probe. Even though the geometric modeller9 specified for use in the EPS-I is limited to planes, cylinders, quadratics and cubics, the EPS-1 framework can accomodate other three dimensional objects. Dimensioning and tolerance modeller Inspection of physical objects by DME and CMMs requires specific data about the dimensions and toler- Known DME Machine Specifleation User Supplied Part Identification Expert Programming System - One 0EPS-1) QuaXty Plans User Support Information DME NC Plan Generator I i Dimensioning and Tolerance Modeler Geometric Modeler • Figure 3 Operational ment of the EPS-I I Dimensioning & Tolerancing Applications Interface Specirgatlon Applications Interface Specification I I ] SC environI | Computer Integrated Manufacturing Systems Volume 7 Number 4 277 Automating the inspection of manufactured parts: M D Reimann and J Sarkis Dimensioning and tolerance AIS The AIS allows a user to retrieve geometric data about a part, and also enables applications to utilize the functional capabilities of the geometric modeller. The D&T model expands the geometric model of the part to include data that is necessary for dimensioning and tolerancing. Unfortunately, the AIS does not accommodate dimensioning and tolerancing data, nor does it enable external applications to access the functional capabilities of the D&T modeller. Therefore, it was necessary to extend the AIS so that it could create, read, modify and delete nodes in the D&T model. The dimensioning and tolerancing applications interface specification (DTAIS) 12 was created to satisfy this need. The DTAIS is similar in concept to the AIS in that it is used to construct the D&T model. Dimensional measuring interface specification There are three classes of interface for linking CAD systems with DME13: • One-to-one interfaces require users to develop their own communication linkages that work with specific devices in their system • One-to-many interfaces allow one CAD system to interface with numerous DME and CMMs • Many-to-many interfaces allow the user to select the most appropriate CAD systems and DME which satisfy their particular needs. The many-to-many interface is the most desirable because it provides the greatest flexibility and has the highest potential for integration of inspection processes. the DMIS s'14"t5 was recently adopted by ANSI as a national standard for many-to-many interfaces. DMIS provides the linkage between the EPS-1 and DME, as shown in Figure 3. Summary and conclusions In this paper, we have presented a review of the advanced numerical control (ANC) processor developed by CAM-I's ANC Program. It was shown how the functional modules of an ANC processor could be used to develop a processor for automated quality and inspection control called Expert Programming SystemOne (EPS-1). To be competitive, manufacturers must produce their products to meet customer requirements in a timely fashion at a competitive price. The EPS-1 is an essential component for achieving these objectives in integrated manufacturing environments. The linkage of the EPS-1 in an operational environment was also described. A description of how the EPS-1 processor would be implemented to inspect representative parts is presented by Reimann and Sarkis 16. Efforts addressing the issue of automating and integrating the inspection planning process have only recently emerged. This is not only 278 Computer Integrated Manufacturing Systems Volume 7 Number 4 due to competitive pressures, but the increased technological availability of various DMEs, specifically coordinate measuring machines which have shown increasing benefits 17. Future research should focus on extending the ANC to include other aspects of automated planning within manufacturing environments. So far, only the framework for the ANC has been developed; operationalizing many of these functional modules is required. Development of decision tools to help in the automation of these steps is also needed. Numerous research possibilities in determining appropriate algorithms and knowledge bases for these decision tools exist for both the ANC and EPS-1. Acknowledgements This work was supported by a grant from the Consortium for Advanced Manufacturing International. References 1 CAM-lAdvancedNumericalControlConceptualDesign-Volume I Project Notebook & Status Report, Computer Aided Manufacturing-International, Inc., Arlington, TX (1979) 2 Brown, C W 'IPPEX: An automated planning system for dimensional inspection', Proc. 22nd CIRP Int. Seminar on Manuf. Syst., Enschede, Netherlands (June 11 1990) 3 EIMaraghy, H A and Gu, P H 'Expert system for inspection planning', Ann. CIRP, Vol 36 No 1 (1987) pp 85-89 4 Menq, C H, Yau, H T and Lai, G Y 'Automated precision measurement of surface profile in CAD-directed inspection', IEEE Trans. Robotics Association, Vol 8 No 2 (April 1992) pp 268-278 5 Menq, C H, Yau, H T and Wong, C L 'An intelligent planning environment for automated dimensional inspection using coordinate measuring machines', J. Eng. 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