An architecture for integrated automated quality control

Journal of Manufacturing Systems Volume 12/No. 4

An Architecture for Integrated Automated Quality Control Michael D. Reimann and Joseph Sarkis, The University of Texas at Arlington

Abstract

TBM TQM TSR

Total quality management for the product lifecycle requires integrating quality control systems with product development, production, and support systems. Integrating automated inspection with advanced computer manufacturing systems components greatly enhances the improvement of products and processes. Presented is an approach to integrate inspection systems with automated manufacturing systems. This step completes the computer-integrated manufacturing loop. Described is an architecture to integrate quality considerations with conventional product characteristics. Elements of an operational environment for this approach are described, along with a framework and functional components that fit in the framework. The framework and the functional components form an architecture called the Expert Programming SystemOne (EPS-1). An example illustrates the operation and functioning characteristics of the EPS-1.

Introduction Computer-integrated manufacturing (CIM) links the primary design and manufacturing functions of the enterprise. Industry and research have been mostly concerned with the integration of computeraided design (CAD), computer-aided manufacturing (CAM), and computer-aided process planning (CAPP). l-a Little effort has been directed to linking quality control and automated inspection in the CIM environment.1,z,s-lo Filling the void is numerically controlled dimensional measurement equipment (DME), including coordinate measurement machines (CMMs), flexible inspection systems, optical comparators, robotic measuring devices, and laser-based measuring devices. Automated DME brings the same advantages to inspection that numerical control (NC) machines bring to manufacturing. A properly integrated system enhances flexibility, increases throughput, reduces setup time, minimizes operator error, improves accuracy, improves product quality, and lowers costs. 1'1L~2 To take full advantage of DME, CIM requires that flexible inspection centers no longer act as islands of automation, but that they be integrated with other elements of automation, including CAD, CAPP, and CAM. 1,in Integration of inspection tools is one issue addressed here. Also presented is a framework for generating automated inspection process plans based on CAMI's advanced numerical control (ANC) processor design. The framework, along with its elements, is called the Expert Programming System-One (EPS-1).s'6

Keywords: Automated Quafity Control, Inspection Process Planning, Quafity Information Systems, Systems Architecture, Standardization

Glossary AIS ANC CAM-I

CMM D&T DME DMIS DRF DTAIS EDT

EPS- 1 NC SPC

Cranfield test-bed modeler Total quality management Tactics stage records

Application interface specification Advanced numerical control Computer-Aided Manufacturing International, Inc. (now Consortium for Advanced Manufacturing International, Inc.) Coordinate measurement machine Dimensioning and tolerancing Dimensional measurement equipment Dimensional measuring interface specification Datum reference frame D&T extensions to the AIS Evaluated dimension and tolerance Expert Programming System-One Numerical control Statistical process control

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Journal of Manufacturing Systems Volume 12/No. 4

Automated Inspection and DME

ure 1. The rest of this section describes the basic

Philosophies of total quality management (TQM) and total quality control (TQC) are gaining greater acceptance from domestic manufacturers. An underlying idea of TQM is for quality at the source, 1'13'14 pointing to the need to monitor the product at all processing stages. In an integrated framework, the inspection process runs simultaneously with actual manufacturing processes for the product, and measurement results immediately correct or adjust the manufacturing processes. Menq et al. :s'16 address specific examples that link a CMM system with a proprietary CAD/CAM system. They developed inspection plans for complex and sculptured surfaces. Merat and Radack a provide an automated inspection process using form features and inspection plan fragments to generate an inspection plan. They used the dimensional measuring interface specification (DMIS) 1"11'17 to standardize their approach. This article describes a general framework to generate inspection process plans. A framework similar to the automated development of numerical control programs for manufacturing processes can g e n e r a t e a u t o m a t e d inspection processes. 2,a'l°'la'14,ls Such a framework is a generative process planning approach for automated inspection similar to generative process planning for CAPP in manufacturing. 4 Often DME is appropriate for data collection and data analysis. Automated CMMs collect dimensional data at rates approaching one measurement point per second, making them an ideal choice for gathering statistical process control (SPC) data. These inspection devices make possible a near real-time SPC system. ~2 Reverse engineering, or design for manufacturability, is greatly enhanced by automated inspection because of dramatically reduced design and redesign times.19

elements of this environment. The EPS-1 also provides a framework and components, described later, to automate an inspection process.

Geometric Modeler A geometric modeler delineates, identifies, and defines the physical characteristics of a part, describing them by their boundaries. The geometric modeler facilitates certain functions specific to inspection. In particular, it detects collision between the probe and part by performing a Boolean intersection on geometric models of the probe and part. Although the geometric modeler2° specified for the EPS-1 is limited to planes, cylinders, quadratics, and cubics, the EPS-1 architecture accommodates other three-dimensional objects.

Dimensioning and Tolerancing Modeler Inspection of physical objects by DME and CMMs requires specific data about the dimensions and tolerances for the geometric features of a part. 2~ Many existing geometric modelers cannot produce the dimensioning and tolerancing information needed by inspection applications. Thus a dimensioning and tolerancing (D&T) modeler 22 was designed and developed. The D&T modeler defines various tolerance nodes and assigns these nodes to one or more geometric features. After adding geometric features to a part model, the D&T modeler K~ln tl~.r Supplied Parl

Idenlificalkm

DMEk|~hine$pt~ifglalo~

-

System - One

Qu,lit} I~an~

Al~licatit~ IniMlce

Operational Environment of the EPS-1

I

f - -

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Today'|nee 81ode~r

kh~leler

•.

An operational environment for linking CAD systems with DME is defined. The EPS-1 was developed through the cooperative efforts of the CAM-I ANC program. The EPS-1 interacts with various external components, as illustrated in Fig-

L ~6(ffs~ J

/tl~llkln~ Inlldllce

I m

I

n

I

/

I

Figure 1 Operational Environment of the EPS-1

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Volume 12/No. 4

• 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 that satisfy their particular needs.

augments the geometries with specific dimensioning and tolerancing data.

Applications Interface Specification Due to the unique capabilities of various geometric modelers, an inspection application may require several modelers. To avoid developing unique interfaces for each combination of application and modeler, a standard interface similar to IGES was developed. The geometric modeling program of CAM-I defined the application interface specification (AIS) to satisfy this need. The AIS is a dynamic interface between modelers and applications software. Modelers and applications designed and implemented to conform to the AIS can interface directly with one another. The AIS defines core capabilities that should be available from any geometric modeler. If a particular modeler can perform a specified function, then the interface acts only as a communications media. On the other hand, when the function is not supported by a modeler, the application interface performs that particular function.

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 dimensional measuring interface specification (DMIS) 1A1"17 w a s recently adopted by ANSI as a national standard for many-to-many interfaces. The DMIS provides the linkage between the EPS-1 and DME as shown in Figure 2.

Information and Database Requirements The EPS-1 requires several databases and files to store dynamic and static data. Some information is retained internally in the processor where it can be created, accessed, modified, and deleted as

A ~

Dimensioning and Tolerancing Applications Interface Specification

l

The AIS allows the user to retrieve geometric data about a part and enables applications to use the functional capabilities of the geometric modeler. The D&T model expands the geometric model of the part to include data 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 modeler. Therefore the AIS was extended so it could create, read, modify, and delete nodes in the D&T model. The dimensioning and tolerancing applications interface specification (DTAIS) 23 was created for this. The DTAIS is similar in concept to the AIS in that it constructs the D&T model.

¢ CADSystemB ~

#

I

I'

¢ CADSystemC ~

#

#

DMIS Format~ i

QIS

System

#

t MSy.,tem, )

Dimensional Measuring Interface Specification

I

DMESystem2 )

L DMESystem3 )

L DMESystem4 ) Inspection or ManufacturingCell

There are three classes of interface for linking CAD systems with DME: 24 • One-to-one interfaces require users to develop their own communication linkages that work with specific devices in their system.

Figure 2 Dimensional Measuring Interface Specifications Environment

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required. Other data is external to the EPS-1 processor and may be retrieved in read-only mode. Figure 3 shows these relationships. The static library files focus primarily on data related to manufacturing elements that do not require frequent updating. External databases include the geometric model database and the D&T database.

inputs. The identification number retrieves the geometric model and the dimensioning and tolerancing model of a part. The DME NC plan generator uses the overall plan to produce DMIS control data and support information for specific DME.

Obtain Operation Plan The user provides required data to the EPS-1 for initiating the automated inspection process. This module determines the scope of the inspection process for the indicated part. Data needed by the EPS- 1 include:

The EPS-1 Architecture Figure 4 illustrates the basic architectural model

• A valid part identification number as defined in the geometric part database. • The type of inspection (for example, courtesy, in-process, or final). • An inspection process strategy. • The DME class or specific DME to be used, if known a priori.

of the EPS-1. This diagram shows the relationships among nine functional modules that form the EPS-1 architecture. The remainder of this section describes the nine functions. The EPS-1 requires a part identification number and an overall process plan as

INTERNAL E P ~ I DATA REQUIREMENTS

All these inputs are required except for DME class/machine. Values provided are validated to ensure that corresponding data files exist in appropriate external databases. Once validated, a header data record is created in a work element table and assigned the values initially input.

Dynamic Databases

Static Library Files

Task Decomposition The task decomposition module determines the evaluated dimension and tolerance (EDT) features to be measured by the inspection process. The EPS-1 automatically determines this based on information obtained by the Obtain Operational Plan module. The part identification and inspection type uniquely identifies the geometric and D&T models of the part. An entire D&T model is obtained through DTAIS subroutine calls to the D&T modeler. The D&T model is used by the task decomposition module to construct a skeletal list of the work elements needed for the inspection process. For each node in the D&T database, an individual work element line item is constructed. Subsequent steps in the EPS-1 use this information to determine other inspection process requirements and characteristics.

External EPS-I Data Requirements

Determine Methods and DME This module performs two functions, determining appropriate NC measurement methods for the inspection process and identifying the most appro-

Figure 3 EPS-1 Data Requirements

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PartIdentification Impeelion Type

] DMECla.~lMachine ] ]It :wctionStrategy DMEMachines Obtain perallona I~ll HeaoerK e c o r o .

~

.

MachineOperator I

|

ti

tI

J Mcqho~ DME Geometric IRItT J and DM ~'.lachlne Modeler Modeler I l,ibrary

Geometric Model Database

Instructions

ElYrFeatures

I

DME

t

II

J

IlL

min

NC DME MethodsSelection Module Module

I

up

Machine Tool

Geometric Modeler Fixture Module

Dependent Control DMENC PlanswithTactics ] Probe Holder Module Module

Clamp Module

----r''ll "•

TacticsModule ~ PlanGenerator StrategyModule Geometric Modeler User Parametric ' Probe

Path

Generator

DMIS CentrelData It ~ Operator ,Instructions [ Produce Iv'nnalAid~~

I s~ppo~t : o~,:r. : ~

C

tro ap~

t~t~ co~t~ot I I I I

F°rmater M°dule ] [ I ]

OperatorInstructionGenerator ] ] ]

Order¢~rato~l

/

GeometricModeler] VistmlAidGenerator

Figure 4 The EPS-I Architecture

priate DME for taking the actual measurements. For the EPS-1, the combination of tolerance class and subfeature class establishes individual NC measurement methods. Once the methods are determined, a DME machine is chosen. If a DME machine was specified during process initialization, the DME selection function is bypassed. Here, the NC measurement methods required for the inspection process are compared with those available from the specified DME to ensure that the DME can take the required measurements. If the DME was not specified, then the EPS-1 compares the capabilities of available equipment against the NC measurement methods required for the inspection process to choose the DME.

Determine Setup Part setup generally applies to the part orientation and fixture and clamp selection in an NC environment. To simplify the process, fixtures and clamps are not incorporated into the initial specification of the EPS-1. Part orientation is accomplished by alignment of part surface normals with DME 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 DME and the part due to improper orientation.

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The above strategy requires the geometric modeler to perform Boolean algebra intersections on the part and probe models to detect potential collisions.

element file, NC plan, and NC tactics are complete, and the user can intervene to make any adjustments. The user can review a graphical representation of the inspection process sequence to show potential collision and coverage problems. The user makes necessary corrections to eliminate any problems. Simple changes can be made without further intervention by the EPS-1.

Determine Probe/Holder This module determines combinations of measurement probes and holders for the inspection process. Selection of a probe can become a complex task when the following factors are considered: • • • •

Generate/Simulate Probe Path This module performs two major functions, generating locational and parametric probe path data and visually simulating that data. Primary input to this module is the NC plan with tactics, and primary output generated is an internal representation of 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 sequentially and contain the subfeatures class, tolerance class, and subfeature name for each entry. The measurement process generates 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. The EDT subfeature class/tolerance class combination dictates the appropriate routine. The routines use specific D&T information to establish actual probe position. Parametric probe path data is mathematically determined for each measurement. The probe path data has two parametrically synchonized curves. One curve represents the probe end, while the other represents the probe axis. Once the parametric probe path is created, it graphically illustrates probe movement relative to the part. The user can review the probe movements over the part to determine coverage and detect collisions.

DME technologies. Probe relative orientation. Multiple probe setups. Probe shape.

Due to this complexity, candidate probes must be identified through elimination. Capabilities of available probes are compared to required measurement characteristics of the inspection process. A probe is determined for each subfeature on the part. Several probes may be required to measure the entire part. The strategy here may be to select probes by minimizing the number of probes for the entire inspection process. Another probe selection strategy might be to maximize the number of measurements obtained from the individual probes.

Detail/Optimize Operation Plan This module uses inspection process information from previous modules to complete the operation plan. The EPS-1 completes the sequence of work elements and determines the corresponding movement tactics for the inspection process. This function performs three activities: • NC plan generation. • Determination of NC tactics. • Review and modification of the NC plan. This module determines sequencing of individual work element items. The NC strategy previously specified by the user forms the basis for the ordering process. Based on this strategy, an appropriate set of logic establishes the specific sequencing of work elements. Types of logic used are dependent on sequencing strategy. Mixtures of heuristic, optimizing, and decision table logic may be employed. Relative positioning of the probe is also determined for every subfeature measurement made. All the processing up to this point has been automatically carried out by the EPS-1. The work

Produce Control Information This module generates numerically controlled DME inspection instructions. These instructions conform to the DMIS. The NC plan with tactics provides the necessary tolerancing information. The internal representation of the probe path retrieves the coordinates of the actual points for every movement and measurement. Combining all this information produces DMIS instructions. This module also allows DME independent control information to be included in the DMIS file.

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Produce Support Information This module develops information that supports the actual NC inspection operation. It is defined so that it can be tailored to support the specific environment of an individual site. 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.

Step 1: Obtain Operation Plan The following data items must be obtained from the user: PART IDENTIFICATION: ANC 101M INSPECTION TYPE: FINAL DME CLASS/MACHINE (Optional): MICRO 4 INSPECTION STRATEGY: MINIMIZE REORIENTATION Validation of this data is accomplished by accessing appropriate files (for example, geometric models, machine tools, and so on) and checking for the existence of the corresponding models based on the user inputs.

EPS-1 Application Illustration A brief example shows the EPS-1 using the CAM-I ANCI01M test part in Figure 5. There is always a concern that a test part may be too simple or not representative of parts encountered in actual practice. The ANC101M part was designed, by a diverse group of manufacturing specialists, specifically to incorporate a difficult and representative collection of features. There are 85 toleranced dimensions and angles on the ANCI01M part. This example will only focus on 11 dimensions and angles, shown in Table 1.

Step 2: Task Decomposition In this function, the EPS-1 will first use the data provided by the user in Step 1. From this, the part identification number and the inspection scope combine to uniquely identify the part and retrieve the D&T model. The single DTAIS command acquires the entire D&T model: Table 1 Specified Tolerancing Measurements on the ANC101M Part

Figure 5 ANCIOIM

Test Part

347

EDT Feature Number

EDT Feature Name

EDT Feature Descrintion

1

CBOREI

Concentricity tolerance of 0.12ram for a 65ram diameter counter bore with a through hole (datum D).

2

HOLE1

Position tolerance of 0.05ram at RFS for a 50ram through hole, measured with respect to datums A, B, and C.

3

AFACE1

Angular tolerance of 0.1ram on a 30 degree face held over the distance in reference to datums A, D, and B.

4

CBORE2

Position tolerance of 0.12ram for a 13ram diameter counter bore, measured with respect to datums A, D," at RFS, and B.

5

PROFIL1

Profile tolerance of 0.2ram for a truncated cylindrical pocket surface, measured in reference to A, D at RFS and B.

6

BHCIRC1

Position tolerance of 0.25mm for a partial bolt hole circle feature on the top face in reference to datums A, D at RFS and B.

7

PLANE1

Perpendicularity tolerance of 0.1mm for the front face with respect to datum B.

8

BHSQR1

Position tolerance of 0.20mm at MMC for four through holes in the base plate with respect to datums A, B, and C.

9

PLANE2

Compound perpendicularity tolerance of 0.1mm for the left vertical face with respect to datum A and 0.15ram with respect to datum B.

10

PROFIL2

Profile tolerance of 0.2ram for two pocket feature surfaces in the lower vertical right face with respect to datums A, D at RFS, and C.

11

PROF1L3

Profile tolerance of 0.2ram for a pocket feature surface in the upper vertical left face with respect to datums A, D at RFS and C.

Journal of Manufacturing Systems Volume 12/No. 4

DGETMO (ANC101M.DT,0,IFAIL)

D&T model. Precedence relationships between work elements are also established. For example, in Table 2, the measurement of datum A must come before the measurement of datum B.

Successful completion of this command signifies the existence of the file in the database. Based on data frow the D&T model database, an initial construction of the work element file is now created. This file is constructed from all toleranced feature nodes in the D&T model file. The feature nodes are requested with the DTAIS command:

Step 3: Determine Methods and DME This module uses DTAIS commands to interrogate the D&T database and decompose the EDT features into EDT subfeatures. Table 4 lists feature and subfeature classes available to the D&T modeler. The tolerance node associated with each subfeature is extracted from the D&T model, again using a DTAIS calling routine. A given subfeature may require a chain of tolerance nodes to obtain the needed data. For example, a planar face may be associated with a tolerance node containing location information and another tolerance node containing information about the distance from a datum. Every tolerance node causes a new entry in the work element table. Each of these entries specifies the tolerance and subfeature class. Table 5 lists tolerance classes supported by the D&T modeler. After the subfeature class and tolerance class entries have been added to the work element table, the DME for inspection can be determined. If a DME was specified by the user, a check is made to see if it can perform the necessary inspections on

DALLND(TYFEAT,NNAMES, NNMLIST,IFAIL) The list of toleranced feature nodes generates skeletal work elements. They directly relate the D&T and geometric models to each other. Table 2 shows the initial construction of line items in the work element table for the specified tolerances. The relationships shown in Table 3 determine the feature classes for each work element. Subsequent processing by the EPS-1 will fill in the other required data fields in the work element records. Besides the EDT features entries in the work element table, other entries pertaining to datums need to be created. These datums will ultimately provide the measurement references for the DMIS instructions. The datums are determined by retrieving all datum reference frame (DRF) nodes from the

Table 2 Work Element Table Entries for EDT Features

Work Element Identification

Process Flaes

EDT Feature

DME Meth~xl Technique/ Sub-Feature Tol Class Class

Sub-Delta/ Setup Sub-Feature Orientation Fixture

Clamps

Probe

Holder

Precedmt Work Element

ANCI0100001

DATUMA

Null

A NC 10100002

DATUMB

Null

00001

ANC 10100003

DATUMC

Null

00002

ANC l0100004

DATUMD

Null

00003

ANC l0100005

DATUMD

RFS

00004

ANCI0100100

CBORELI

A NC I 0100200

HOLEI

ANC 10100300

AFACEI

ANC 10100400

CBOREL2

ANC 10100500

PROFILI

ANC 10100600

BHCIRCI

ANC 10100700

PLANEI

ANC I 0100800

BHSQRI

ANC 10100900

PLANE2

ANCI0101000

PROFIL2

I00

PROFIL3

ANCIOIOI

348

Sequence Number

Journal of Manufacturing Systems Volume 12/No. 4

Table 3

Table 4

Categorization of Specific Part Features

Dimensioning and Tolerancing (D&T) Feature Classes

Featur~ Nam¢

Class

Feature Cate~,orv

CBORE1

Internal Cylinder

HOLE1

Internal Cylinder

AFACE1

Planar Face

CBORE2

Internal Cylinder

PROFIL1

Profile Group

BHCIRC1

Partial Bolt Hole Circle

PLANE1

Planar Face

BHSQR1

Bolt Hole Square

PLANE2

Planar Face

PROFIL2

Profile Group

PROFIL3

Profile Group

Resolution

Simple Features Planar Face

Plane

Size Features Internal Cylinderor Hole

Line

External Cylinderor Circular Boss

lane

Internal Opposed Planes (Slot)

Plane

External Opposed Planes (Block)

Plane

Compound None

Profile Group

Table 5 Dimensioning and Tolerancing (D&T) Tolerance Classes

each subfeature. This is done by interrogating a truth table of subfeature classes, tolerance classes, and DME. If an appropriate DME exists in the table, then the corresponding DME is selected; otherwise the EPS- 1 continues searching for a substitute DME. After the DME is determined, it is identified in the work element table header record.

Category

ClaBs

Location:

Distance

Resolved point, line or plane

Surface Profile

Any feature, no resolve

Surface Runout

Planar face, internal/external cylinder

Angle Relative

Qualified line or plane

Angle Base

Qualified point, line or plane

An~adty

Resolve point, llne, or plane

Size

Feature of Size (FOS)

Radius

Feature of Size (FOS)

Form:

Form

Any feature, no resolve

Surface Finish:

Surface Finish

Any feature, no resolve

Orientation:

Step 4: D e t e r m i n e Setup The first step in this function establishes the datum reference frame (DRF) for the part. The DRF is a reference coordinate system for part and feature orientations. The DRF in this example comprises datums A, B, and C. Initially, the normal directions of each subfeature on the part must be determined. Examples of subfeature normal vectors for the ANCI01M test part include:

Qualified point, llne or plane

Location

Size:

Measurement system orientation vectors are compared to each subfeature normal vector. This determines candidate part orientations from which to measure individual subfeatures. The general strategy for determining candidate measurement system orientation vectors is to use the reference coordinate system or coordinate systems aligned with respect to the subfeature surface normals. When evaluating a measurement system orientation vector, six mutually orthogonal vectors are compared to the desired

• The bottom face--This is datum A on the part and lies in the X - Y plane of the DRF. Therefore, the subfeature normal vector is 0 in the X direction, 0 in the Y direction, and - 1 in the Z direction. • The through hole--This cylindrical hole is on an axis that is perpendicular to datum A. The vector along the axis is 0 in both the X and Y directions. Because the hole is open at both ends, the Z direction vector can be either + 1 or - 1 .

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subfeature normal vector. Thus, it is possible to determine when two perpendicular surfaces can be measured in the orientation. Table 6 shows normal vectors, subfeature type, assignment of orientation vectors, and evaluation of orthogonal measurements for each of the 11 subfeatures in Table 2. The subfeature types include CYL (cylinder), FACE (planar face), and PROFL (profile). Six unique measurement orientation vectors are as follows:

Step 5: Determine Probe/Holder Probe selection usually requires heuristic techniques. Some factors considered when selecting probes include which DME to use, tolerancing prerequisites, and orientation requirements. The next step determines the type of probe holder by selecting the one probe holder that goes with the selected probe. As probes and probe holders are established, this information is added to the work element table. For this example, it is assumed that two probes and one probe holder are required:

(0,0,1)-OrientA (0,0,- 1)'OrientB (0.5,0,0.866)-OrientC (0,-1,0)-OrientD ( 1,0,0)-OrientE (-1,0,0)-OrientF

a A Star probe (PROB1) for surfaces parallel or perpendicular to DRF A; and • A single-tipped probe with a 30 ° inclination (PROB2) for the face that is angled at 30 ° relative to DRF A.

Five of these six orientation vectors are mutually orthogonal to one another. Therefore, the five vectors reduce to a single measurement orientation system. If the DME is a three-axis machine, then two orientations of the ANC101M test part are required to measure the subfeatures. Thus, a single setup orientation accommodates the 11 specific features of the part.

Step 6: Detail/Optimize Operation Plan This module uses results from previous functions to perform three basic activities, NC plan generation, determination of NC tactics, and review/ modify NC plan. • NC plan generation--For this example, the user requested a strategy to minimize reorientation of the part. The NC plan generator will sequence the work element table to achieve this goal. The heuristic process uses the primary part DRF for the first setup. All work elements using this setup are assigned a sequential number starting with the first element on the list. Subsequent part setups are assigned based on maximizing the number of inspections obtained for each setup. Work elements are assigned sequence numbers based on the setup. This process continues until all work elements are exhausted.

Tab/e 6

Determination of Measurement Orientations

Sub-Feature Class

|Oentlfication INCYLND1

Cyl

Normal Vector

Measurement Orientation Orthogonallty Indicator Vector + X -X +Y -Y + Z -Z

(0,0,1)

OrientA

N

N

N

N

N

Y

(0,0,-1)

OrientB

N

N

N

N

Y

N

OfientA OrientA

N N

N N

N N

N N

N Y

Y N

INCYLN2

Cyl

(0,0,1) (0,0,-1)

PLFACE1

Face

(.5,0,.866)

OdentC

N

Y

N

N

N

N

Cyl

(0,-1,0)

OrientD

N

N

Y

N

N

N

INCYLND3 PROFL1

Profl

"

INCYLND4

Cyl

(0,0,1)

OrientA

N

N

N

N

N

Y

INCYI..ND5

Cyl

(0,0,1)

OrientA

N

N

N

N

N

Y

INCYLND6

C'y!

(0,0,1)

OrientA

N

N

N

N

N

Y

INCYLND7

Cyl

(0,0,1)

OrientA

N

Y

Y

Y

N

Y

Face

(1.0,0)

OrientE

N

Y

Y

Y

N

Y

INCYLND8

Cyl

(0,0,1) (0,0,-1)

OrientA OrientB

N N

N N

N N

N N

N Y

Y N

INCYLND9

Cyl

(0,0,1) (0,0,-1)

OrientA OrientB

N N

N N

N N

N N

N Y

Y N

INCYLND10

Cyl

(0,0,1) (0,0,-1)

OdentA OrientB

N N

N N

N N

N N

Y N

N Y

INCYLND11

Cyl

PLFACE2

(0,0,1)

OrientA

N

N

N

N

Y

N

(0,0,-1)

OricntB

N

N

N

N

Y

N

OrientF

N

Y

PLFACE3

Face

(-1,0,0)

Y

N

PROFL2

Profl

"

-

.

.

Y .

Y .

.

PROFL3

Profl

"

-

.

.

.

.

.

For the selected subfeatures of ANCI01M, the inspection sequence is assigned as shown in Table 7. In this example, it is assumed that a secondary strategy is to minimize probe changes. Therefore, all the work elements using PROBE1 are sequenced before the 30 ° face. • Determination of NC tactics--The tactics that will allow measurement of each dimension for every subfeature are now determined. The basic technique is to position the probe over the center of the subfeature to be measured. The position is then incorporated into an appropriate series of

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Table 7a W o r k E l e m e n t T a b l e E n t r i e s for S e q u e n c e N u m b e r s

Element Identification

Work

Process Flags

EDT

Feature

D M E Method Technique/ Sub-Feature T o l Class Class

Sub-Deltld Setup Sub-Feature Orientation Fixture

Clamns

Probe

Holder

Precedent Work Element

Sequence Number

ANCI0100001

DATUMA

Null

PROB1

PHI

A NC 1 0 1 0 0 0 0 2

DATUblB

N ull

PROB I

PHI

00001

2

ANC I 0 1 0 0 0 0 3

DATUMC

Null

PROBI

PHI

00002

3

A NC I 0 1 0 0 0 0 4

DATUMD

Null

PROBI

PHI

00003

4

ANC I 0 1 0 0 0 0 5

DA'I'LIM D

RFS

PROB

PHI

00004

5

ANC 1 0 1 0 0 1 0 0

CBORELI

ANCIOI00101

CBORELI

A NC I 0 1 0 0 2 0 0

HOLEI

ANC I 0 1 0 0 2 0 1

HOLEI

ANC 1 0 1 0 0 3 0 0

AFACEI

A NC I 0 1 0 0 3 0 1

AFACE I

1

1

Location

Incyl

INCYLNDI

OrientA

*

*

PROBI

Radius

Incyl

INCYLND2

OrientA

*

*

PROB1

PHI

7

Angularity

Plnfc

PLFACEI

OrientA

*

*

PROB2

PHI

30

Location

Incyl

INCYI..ND3

OrientA

*

*

PROBI

PHI

8

Profl

PROFLI

OrientA

*

*

PROBI

PHI

9

6

ANC 1 0 1 0 0 4 0 0

CBOREL2

ANC 10100401

CBOREL2

A NC 1 0 1 0 0 5 0 0

PROFIL I

A NC I0100501

PROFIL 1

Profile

ANC 1 0 1 0 0 6 0 0

BHCIRCI

Coheir

ANC 10100601

BHCIRC 1

Location

lncyl

INCYLNIM

OrientA

*

*

PROB1

PHI

10

ANC I 0 1 0 0 6 0 2

BHCIRC 1

Radius

Incyl

INCYLND4

OrientA

*

*

PROB1

PHI

II

ANC 1 0 1 0 0 6 0 3

BHCIRC l

Location

lneyl

INCYLND5

OrientA

*

*

PROB1

PHI

12

ANC 1 0 1 0 0 6 0 4

BHCIRC 1

Radius

Incyl

INCYLND5

OricntA

*

*

PROB1

PHI

13

ANC 1 0 1 0 0 6 0 5

BHCIRC 1

Localion

Incyl

INCYLND6

OrientA

*

*

PROB1

PHI

14

* Not I m p l e n l e n t e d in E P S - 1 .

tactics stage records (TSR) for the subfeature. The actual probe movements required to measure the dimensions are left for a later step.

step is only used to view the sequence of measurements. Modifications to the work element table and the TSR are the responsibility of the user at this stage.

The TSR are constructed in a separate data file from the work element table file. The necessary fields for TSR include work element identification, stage name, tool axis control, from tool end, from tool vector, maximum feed rate, and minimum feed rate. Table 8 provides an abbreviated layout of the TSR for the bolt hole circle feature.

Step 7: Generate/Simulate Probe Path The basic concept in generating the parametric probe path is to use the TSR and work element information to determine two sequences of parametric curves. One curve represents the probe end and the other represents the probe axis at corresponding parametric values. Besides the tactics information, tolerance information for each required inspection is necessary, including tolerance types and particular tolerance values. This information is accessible from the D&T modeler by using the EDT subfeature name from the work element table. The parametric curves are developed by processing the work element table entries in ascending order of sequence number. As the work elements

• Review/modify NC plan--Here the user can graphically review the tactical movement of the probe about the part. This movement shows the sequence in which the subfeatures are measured. Because the data generated up to this stage do not contain any parametric representation of the probe motion, very little can be determined about the actual measurements. The user may be able to detect extreme discrepancies, but usually this

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Journal of Manufacturing Systems Volume 12/No. 4

Table 7b Work Element Table Entries for Sequence Numbers

Work Element ldentificatkm

Process Fla~,s

EDT

Feature

D M E Meth(xl Technique/ Sub-Feature Tol Class Class

Sub-Delta/ Setup Sub-Feature Orientation Fixture

Clamvs

Probe

Holder

W ~ k Element

Number

A NC I 0 1 0 0 6 0 6

BHCIRC 1

Radius

Incyl

INCYLND6

OrientA

*

*

PROBI

PHI

15

A NC I 0 1 0 0 6 0 7

BHCIRC1

Location

Incyl

INCYLND7

OricntA

*

*

PROBI

PHI

16

A NC 1 0 1 0 0 6 0 8

B HCIRC I

Radius

Incyl

1NCYI3qD7

OrientA

*

*

PROBI

PHI

17

A NC I 0 1 0 0 7 0 0

PLANEI

A NC I 0 1 0 0 7 0 1

PLANEI

Angularity

Plnfc

PLFACE2

OrientA

*

*

PROBI

PHI

18

ANC 1 0 1 0 0 8 0 0

BHSQRI

Consqr

A NC 1 0 1 0 0 8 0 1

BHSQR 1

Location

Ine~,'l

INCYLND8

OrientA

*

*

PROBI

PHI

19

Radius

Incyl

INCYI2qD8

OrientA

*

~'

PROBI

PHI

20

A NC 1 0 1 0 0 8 0 2

BHSQR 1

ANC 10100803

BHSQR1

Location

Ineyl

INCYLND9

OrientA

*

*

PROBI

PHI

21

ANCIO100804

BHSQRI

Radius

Incyl

INCYLND9

OrientA

*

*

PROB1

PHI

22

ANC I 0 1 0 0 8 0 5

BHSQR l

Location

Incyl

INCYI..NDI 0

OrientA

*

*

PROB1

PHI

23

ANCIOI00806

BHSQRI

Radius

Incyl

INCYLNDI0

OrientA

*

*

PROBI

PHI

24

ANC I 0 1 0 0 8 0 7

BHSQRI

Location

Incyl

INCYLNDI 1

OrientA

*

*

PROB I

PHI

25

ANC 10100808

BHSQR 1

Radius

Incyl

INCYLND11

OrientA

*

*

PROBI

PHI

26

A NC I 0 1 0 0 9 0 0

PLANE2

A NC I 0 1 0 0 9 0 1

PLANE2

Angularity

Plnfc

PLFACE3

OrienlA

*

*

PROBI

PHI

27

A NC I 0 1 0 1 0 0 0

PROFIL2

ANCIOI01001

PROFIL2

Profile

Prolf

PROFL2.

OrientA

*

*

PROB1

PHI

28

Profile

Profl

PROFL3

OrientA

*

*

PROBI

PHI

29

ANCIOI01100

PROFIL3

ANCIOI01101

PROFIL3

* Not I n l p l e m e o t e d in E P S - I .

Each template contains the moves and probe contact points relative to this point for making the required measurement. For example, if the subfeature is a hole (internal cylinder), the tactics record for measuring the position of the cylinder gives the centerpoint of the cylinder. A template called HOLE_POSITION uses this point and the length of the cylinder (determined from the geometric model) to determine the moves necessary to measure at least six points defining the cylinder. Templates used to measure external cylinders are somewhat more complex because of the inability of the probe to travel through the centerline of the cylinder. Even more difficult is for a template to measure a dimension of a planar face. To make this measurement, the two faces adjacent to the planar face must be found and the points for measurement determined.

are processed, previously processed work elements are checked for the same EDT subfeature name. If so, a check is made to see if the previous measurement provides the required tolerance information for the current measurement. If the previous measurement is sufficient, then no probe path is generated. For example, the holes in the bolt hole require location and radius tolerances. No additional probe path data needs to be generated for the radius tolerance because the measurement for location is sufficient. If no previous work elements have the same EDT subfeature name, the tactics records for the work element are used to create nonmeasurement moves. The moves necessary to perform a measurement are determined by calling a template that describes the moves for a given tolerance type and subfeature class. The measurement tactics record gives a standard reference point based on the subfeature class.

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Table 8 Tactics Stage Record for Bolt Hole Circle

Work Element Identification

Stage Name

Control

From Tool End X Y Z

X

To Tool End Y Z

Feedrate Max, Min,

Depart

Fixed Fixed Fixed

100.0 100.0 100.0

106.0 115.0 106.0 115.0 106.0 115.0

100.0 100.0 100.0

106.0 115.0 106.0 115.0 106.0 115.0

50 25 50

25 5 25

Entry Mes'pos Depart

Fixed Fixed Fixed

100.0 100.0 100.0

106.0 115.0 106.0 115.0 106.0 115.0

100.0 100.0 100.0

106.0 !15.0 106.0 115.0 106.0 115.0

50 25 50

25 5 25

Entry Depart

Fixed Fixed Fixed

64.5 64.5 64.5

85.5 85.5 85.5

115.0 1! 5.0 115.0

64.5 64.5 64.5

85.5 85.5 85.5

115.0 115.0 115.0

50 25 50

25 5 25

ANCI0100604

Entry Mespos Depart

Fixed Fixed Fixed

64.5 64.5 64.5

85.5 85.5 85.5

115.0 115.0 115.0

64.5 64.5 64.5

85.5 85.5 85.5

115.0 115.0 115.0

50 25 50

25 5 25

ANCI0100605

Entry Mesrad Depart

Fixed Fixed Fixed

100.0 100.0 100.0

44.5 44.5 44.5

115.0 115.0 115.0

100.0 100.0 100.0

44.5 44.5 44.5

115.0 115.0 115.0

50 25 50

25 5 25

ANC10100606

Entry Mespos Depart

Fixed Fixed Fixed

100.0 100.0 100.0

44.5 44.5 44.5

115.0 115.0 115.0

100.0 100.0 100.0

44.5 44.5 44.5

115.0 115.0 115.0

50 25 50

25 5 25

ANCI0100607

Entry Mesrad Depart

Fixed Fixed Fixed

100.0 100.0 100.0

24.0 24.0 24.0

105.0 105.0 105.0

!00.0 100.0 100.0

24.0 24.0 24.0

105.0 105.0 105.0

50 25 50

25 5 25

ANC10100608

Entry Mespos Depart

Fixed Fixed Fixed

100.0 100.0 100.0

24.0 24.0 24.0

105.0 105.0 105.0

100.0 100.0 100.0

24.0 24.0 24.0

105.0 105.0 105.0

50 25 50

25 5 25

ANCI0100601

Entry

Tool Axis

Mesrad

ANCI0100602

ANCI0100603

Mesrad

After the appropriate measurement template is called, the remaining stages in the tactics record are used to move the probe away from the subfeature. As the moves are identified, the parametric probe path is mathematically constructed and stored in a file in an internal form. The internal representation of the probe path graphically simulates the probe path movements. This requires the use of a geometric model and allows the user to determine coverage and detect collisions. The user may correct any problems by returning to any of the previous steps.

Step 9: P r o d u c e S u p p o r t I n f o r m a t i o n Processing performed by the EPS-1 to this point has been fully automated. A minimal amount of intervention by the DME operator is needed to set up the DME and part for automatic inspection. Information from the EPS-1 for the operator to accomplish this task includes: • • • • •

The measurement process plan. DME identification and parameter specification. Probe and holder specification. Detailed inspection plans. Identification of the DMIS formatted control data file. • Target part specification.

S t e p 8: P r o d u c e C o n t r o l I n f o r m a t i o n

This step develops control information in a DMIS format. Creation of DMIS instructions requires the DRF, measurement points, tolerance information, the probe, and probe moves. Figure 6 provides an example of the DMIS instructions necessary to measure four of the holes in the partial bolt hole pattern on the ANCI01M part.

Summary and Conclusions Incorporating quality considerations of the product and process along with more traditional computer-aided tools used in CIM will fully lever-

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available technologies. T h e m o s t p r o m i s i n g areas for future work include:

GOTO/225.000,125.000,-20.00 RECAU./D(DATSE'r2) M(BOL~C)

= MACROfl~I,Z1,P~DIAM,'LAB F.LI",'LABEL2",'LABEL3",'LABEI~"

• Specification and standardization o f interfaces n e e d e d to a c c o m p l i s h interaction with c o m p o nents that are external to the EPS-1, specifically the delineation o f the functions and formats that are minimally required to m o d e l physical parts f r o m both a g e o m e t r i c and d i m e n s i o n i n g and tolerancing standpoint. • Identification o f information r e q u i r e m e n t s via data modeling techniques. A considerable a m o u n t o f w o r k has already been d o n e in this area by the PDES initiative and on the CAM-I QIS database project. • Structuring and i m p l e m e n t i n g o f the EPS-1 f r a m e w o r k b a s e d on object-oriented techniques. • Use o f b l a c k b o a r d techniques to control the operation and e x e c u t i o n o f the EPS-1. • Optimization o f conflicting goals can be a c c o m plished via artificial intelligence techniques.

GOTARGfXI,llOZ1

GOTO/XLX25,ZI GOTO/XI,110,Z1 ENDGO

D(I.,ABIELI) =TRANS/XORIG,XI,YORIG,XI,YORIG,0,ZORIG,Z1 F(LABEL2) - FEAT/CIRCLE,INNER,CART,0,0,0,10.000

T(L,~tU.3).TOL/DtAM,-0.000,0_S0,F(t.ABEta) T(LABEI~) =TOL/TOS,2D,.25,F(LABEL2) MEAS/CIRCI.E,F( LAB EL2),4 PTMEAS/POL,R,0,110

GOTO/XI,II0,Z1 PTMEAS/POL,R,90310

GOTO/Xa,n0,Z1 PTMEAS/POL,R,180,110 GOTO/XI,H0,Zt PTMEAS/POL,R,270JI0 GOTO]X1,125Z1 ENDMAC C~CAI~g(D~--I CRY)0.000,-41.000,5.10,000,('I3EMFDATI ),(HOLE2B_F),(H2BDIA_T),(H2B POS_T) EV/d./'r(H2eOIA a3 OUTPUT/FA(HOLE2B_F),TA(H2BDIA_T)

EVAL/T(H21BFOS T) OUTPUTIFA(HO~-2B F),TA(H2BPOS_T) R~:CALL/D(DATSET2)

CALL/M(BOLTCICR),.35..~7,.20_~0,5,10.0O0,(TEMPDATI),(HOLE4B_F),(H4BDIA_T),(H4BPOS_T} EVAL/T(H4BDIA 3") OUT]PUT/FA0[-IO~-AB_F),TA(H4BDIA T) EVAL/'T(H4BPOS T) OUTPUT/FA(n O~4B_F),TA(H4BPOS_T) RECAI~/D(DATSET2) CALL/M(BOLTCICR),.35_507,2/)_500.5,10.000,(TEMPDAT1),(HOLE6B_F),(H6BDIA T),(H6BPOS_T) EVAL/T(H6BDIA T) ou'rPUT/FA(HO[.E6B F).TA(H6BDIA_T) t~V,bd./T(I-.16BFO$ T) OUTIWJr/FA(nO~B_I~,TA(H6BPOS T) RECAIJL/DtDATSL~-r2) CALL/M(BOLTCICR),0.0G0,41.000.5,10.000,(TEMPDAT1),(UOLESB_F),(HSBDIA_T),(H8BPOS T) EVAL/T(HSBDIA 1") OLrI~UT/FA(HO~ESB F),TA(H8BDIAT) EVAL/T(H8BFOS T) OUTPUT/FA(HO~SB_ F).TA(H8BPOS_T)

References I. D. Stovicer, " C M M s Key to Plant With a Future," Automation, vol. 37, no. 12 (December 1990), pp. 24-25. 2. P.Y. Jiang, R.J. Zhao, and Q.Q. Chu, "INSPECTOR: A CAD

Figure 6 DMIS Instructions for Measuring the Bolt Hole Circle

Directed Intelligent Inspection Planning System for Coordinated Measuring Machines," Proceedings, 1991 International Conference on Computer Integrated Manufacturing (Singapore: 1991). 3. M.A. Donmez, "Developmentof a New Quality Control Strategy for Automated Manufacturing," Proceedings, Manufacturing International-1992 (Dallas: March 1992). 4. R. Groppetti and Q. Semeraro, "Generative Approach to Computer Aided Process Planning," Proceedings, International Conference on Computer Aided Production Engineering (Edinburgh: April 1986). 5. M.D. Reimann and J.W. Fowler, "The Expert Programming System-One (EPS-I)," Proceedings, Fourth InternationalConference of the State-of-the-Arton Solids Modeling, sponsored by CAD/CIM Alert and CAM-I (Boston: May 1987).

age its potential benefits. In an integrated f l a m e w o r k , the inspection process runs simultaneously with actual m a n u f a c t u r i n g processes. T h u s the results f r o m m e a s u r e m e n t s correct the manufacturing process in real time. A f r a m e w o r k similar to a d v a n c e d numerical control serves as the logical m e c h a n i s m for automating the inspection process. C o n s i d e r a b l e d e v e l o p m e n t w o r k has been undertaken to define and refine the EPS-1 architecture. P r o o f - o f - c o n c e p t has been d e m o n s t r a t e d for the EPS-1. Presently there are several attempts to link CAD systems with automated DME and thus close the loop in the CIM e n v i r o n m e n t . A p r o t o t y p e i m p l e m e n t a t i o n using the EPS-1 approach is currently u n d e r d e v e l o p m e n t at Allied-Signal. 2'7 T h e expert manufacturing programming system tEMPS) 25 also uses concepts f r o m the EPS-1. R e c e n t l y e m e r g i n g technologies m a k e i m p l e m e n tation o f the EPS-1 approach viable; h o w e v e r , b e f o r e a fully automated quality control system can be realized, additional research and d e v e l o p m e n t is needed. Important issues can be resolved with

6. The Expert Programming System-One (EPS-I ), Task One Design Review, R-87-ANC-01 (Arlington, TX: Computer Aided

Manufacturing-lnternational, Inc., 1987). 7. C.W. Brown, "IPPEX: An Automated Planning System for Dimensional Inspection," Proceedings, 22nd CIRP International Seminar on Manufacturing Systems, held June 11, 1990, Enschede, The Netherlands. 8. F.L. Merat and G.M. Radack, "Automatic Inspection Planning Within a Feature-Based CAD System," Robotics & ComputerIntegrated Manufacturing, vol. 9, no. 1 (1992), pp. 61-69. 9. H.A. EIMaraghy and P.H. Gu, "Expert System for Inspection Planning," Annals ofCIRP, vol. 36, no. I (1987), pp. 85-89. 10. D.T. Pham, K.F. Martin, and L.P. Khoo, "A Knowledge-Based Preprocessor Generator for Coordinate-MeasuringMachines," International Journal of Production Research, vol. 29, no. 4 (April 1991), pp. 677-694. I 1. R.R. Schreiber, "CMMs: Traits, Trends, Triumphs," Manufacturing Engineering, vol. 104, no. 4 (April 1990), pp. 31-37. 12. R. Knebel, "CMMs Speed Repair in Aerospace," Automation, vol. 37, no. 1 (January 1990), pp. 32-41.

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23. R.H. Johnson, Dimensioning and Tolerancing Final Report, R-84-GM02.2 (Arlington, TX: Computer Aided ManufacturingInternational, Inc., May 1985). 24. J.H. Zink, "Closing the CIM Loop With CAM," Automation, vol. 36, no. 1 (1989), pp. 48-50. 25. "EMPS--Making Automated NC Programming Feasible," FM Magazine, vol. 6, no. 1 (January 1988), pp. 25-26.

13. M.I. Dessouky, S.G. Kapoor, and R.E. DeVor, " A Methodology for Integrated Quality Systems," Journal of Engineering for Industry, vol. 109 (August 1987), pp. 241-247. 14. K.J. Dooley, S.G. Kapoor, M.I. Dessouky, and R.E.DeVor, "An Integrated Quality Systems Approach to Quality and Productivity Improvement in Continuous Manufacturing Processes," Transactions ofASME, vol. 108, no. 4 (November 1986), pp. 322-327. 15. C.H. Menq, H.T. Yau, and G.Y. Lai, "Automated Precision Measurement of Surface Profile in CAD-Directed Inspection," IEEE Transactions on Robotics and Automation, vol. 8, no. 2 (April 1992), pp. 268-278. 16. C.H. Menq, H.T. Yau, and C.L. Wong, "An Intelligent Planning Environment for Automated Dimensional Inspection Using Coordinate Measuring Machines," Journal of Engineering for Industry, vol. 114 (May 1992), pp. 222-230. 17. ANSI/CAMI 101-1990 Dimensional Measuring Interface Specification (Arlington, TX: Computer Aided Manufacturing-International, Inc., 1990). 18. K. Preiss and E. Kaplansky, "Automated Part Programming for CNC Milling by Artificial Intelligence Techniques," Journal of Manufacturing Systems, vol. 4, no. 1 (1985), pp. 51-63. 19. J.V. Owen, "CMMs for Process Control," Manufacturing Engineering, vol. 107, no. 2 (February 1993), pp. 39-41. 20. CAM-I Test Bed Modeler, PS-85-G-01 (Arlington, TX: Computer Aided Manufacturing-lnternational, Inc., 1985). 21. ANSI YI4.5M, Dimensioning and Tolerancing, ANSI YI4.5M1982 (New York: American Society of Mechanical Engineers, 1982). 22. CAM-I D&T Modeler Version I .O--Dimensioning and Tolerancing Feasibilit3, Demonstration Final Report, PS-86-ANC/GM01 (Arlington, TX: Computer Aided Manufacturing-lnternational, Inc., November 1986).

Authors' Biographies Michael Reimann is a doctoral candidate in management science at the University of Texas at Arlington. He holds a BS in computer science from California Polytechnic State University, an MS in computer science from Southern Methodist University, and an MBA from the University of Dallas. Mr. Reimann specializes in the research and development of methodologies for quantifying and systematically addressing complex business issues. He has conducted numerous projects involving the joint participation of commercial companies, industry consortiums, and the military during the past 20 years. He is a certified systems professional (CSP) and a certified management consultant (CMC). Dr. Joseph Sarkis is an assistant professor in the Department of Information Systems and Management Sciences at the University of Texas at Arlington. He received his PhD from the State University of New York at Buffalo. His research interests are in the strategic management, integration, and justification of advanced manufacturing technologies. Dr. Sarkis has published in a number of academic journals and proceedings. He is a CPIM and a member of ORSA/ TIMS, APICS, and DSI.

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