Integration of Engineering Functions/Disciplines in CIM

Leo Alting - Submitted by T. Wanheim (1). Institute of Manufacturing Engineering, Technical University of Denmark

In the last few years many of the hardware and software elcments necessar? to establish CIM-system Igomputer Integrated >:anufact:rrinql have been developed but still many problems have t o be solve?. espe- cially concerning integration of engineerixg functions?8isciplines into CAD/CAM and CIM in a broarler context. The present paper describes the dcvelopment of a number of comggter aided engineerin3 application modu- les (solutions) Which can provide both integration and s!lpport of important mechanical. design axz-'. nanu- facturin? activities. Following subjects will be discussed: integration of engineering functions into CAD!CAI! inclding software solutions, classification and co?ing, logics for selectin? materials, pro- cesses etc. inteqrated in design, generative process planning, automated part f a m i l y desiqn and wanu- facture and CI?I-mir.iat.ure laboratory. The philosophv in developing these engineering integration and support nodules has been to focus on the loaics and decision making concepts so that the user easily can implement his own looics,'decision strcctlire anr' dati without spending tine on tedious programins. Fur- ther integration of these modales to otter software nnckages including CAD:CA!l systems p l a y s a very im- 3ortant role. Only b2: i3teyration and ::tilization of corxon (eventuallv local) databases the full ad- vantaqe of the new technology can !,e expected.

1. INTRODUCTION

In the last few years many of the hardware and soft- ware elements necessary to establish CIM-systems (Computer Integrated Fnufacturing) have been devel- oped, but sTil1 many problems have to be solved espe- cially concerning integration of engineering func- tions/disciplines into CAD/CAM and hence CIM sy- stems.

CIM is here defined as (1) : "A system in which dist- ributing computing network and common databases are used for combining and coordinating into a harmonic whole such functions as product and process design, planning, scheduling, purchasing, production, inspec- tion, assembly, handling, management and marketing of discrete consumer or producer goods".This definition allows every company to make an interpretation which is in accordance with its own structure and culture.

To try to identify some of the areas where industry has concerns i.e. feels lack of knowledge, standards etc.,CAM-I made a survey in industry ( 2 ) . Some of the major areas of concern were: (a) software transporta- bility, ( 5 ) system mission, goals, and rationale, (c) obtaining management support, (d) identifying system activities and interrelationships and (el data/soft- ware interfacing with existing systems. Included in these concerns were algorithm development, classifi- cation and coding, integration of engineering func- tions in CAD/CAM systems i.e. expert systems to cope with these problems.

Much research and development work are carried out all over the world to supply solutions to these con- cerns. Especially should be mentioned the standardi- zation work progressing rapidly both in USA (General Motors/Boeing*s MAP/TOP) and Europe (EEC - Esprit etc). These developments will diminish the "nightma- res" of integrating hardware into CIH-systems. At the Laboratory of Process and Production Engineering (In- stitute of Manufacturing Engineering), Technical Uni- versity of Denmark research and development are car- ried out concerning computer based support of engi- neering functions and their integration into CAD/CAM and thus in a broader context in CIH. The engineering functions dealt with are mainly process and produc- tion engineering functions and their integration with engineering design functions.

2. Integration of engineering functions in CAD/CAM

The research and development work have been based on the functional structure (hardware and software) shown in Figure 1. The basic software systems are: 0- perating system (VAX/VHS), Standard CAD/CAM system (Auto-Trol series 7 0 0 0 ) . DCLASS (decision and U i - fication software) and Database.

DCLASS TM ( 6 ) . which was developed by Brigham Young University (Prof. D.K. Allen 6 Ron Millet1,USA. is an effective tool in information handling, decision ma- king and logics processing. It is easy to interface with other software packages (CAD/CAM, database sy- stems etc.) which makes it well suited to be a "ma- ster element" in a truely integrated CIM-system where automated and effective applications are based on u- tilization of the best features of the different a- vailable software packages. DCLASS is a flexible o- pen-ended, multipurpose tree processer with a built- -in ultra high level programming language, which will

allow engineers or technical personnel to develop and implement information handling and decision making programs tailored to the specific needs in the compa- ny. The solution of the complex engineering problems will necessarily have to be based on logical structu- res, functional relationships, systematic procedures and utilization of information in order to specify a proper solution.

Focusing on the integration of engineering functions with CAD/CAM systems it appears that several aspects of integration can be identified. Table 1 shows the major areas of research and development at the Insti- tute of Manufacturing Engineering and those marked with a ( * I will be described later in this paper.

It should be emphasized that the approach used in the research and development work is to develop engi- neering functions support modules covering various areas and to develop and handle the logics/algorithms so that the user easily can add his own details and data.

Before describing the selected modules to be presen- ted here a few comments should be given to classifi- cation and coding which is a key t oo l for effective storage and retrieval of information and data. Disc- rete workpiece items can be classified and coded and the resulting, currently updated database can then provide the needed information to gain the benefits of group technology and to match the production sy- stem with the actual production requirements. Other items like engineering materials, manufacturing proc-

Figure 1: Functional structure used to support and integrate engineering functions in CAD/CAM and CIM, ( 3 1

Annals of the ClRP Vol. 35/1/1986 31 7

Table 1

ENGINEERING FUNCTIONS - CAD/CAM integration

. Engineering and producibility logics inte- grated in design - Material selection - Process capability analyses/design for

- Design for assembly/product structuring - Check functions machining, casting, welding etc.

. Generation (automatic) of manufacturing specifications from product/component model/database - Process plan generating (including

operations, toolings and machines) - Design of speciallcomplex toolsldies - NC-programming - Assembly plan generation - Production system performance simulation . Product/part family design macros - Systematic procedures

- Standard design rules logics - Integrated and automated manufacturing specifications

esses, production equipment or production systems, standard or special tools etc. can also be classified and coded and similar benefits can be obtained. DCLASS can accomodate any existing or user developed classification system. The multipath, multilevel and flexible coding format capabilities allow an item to be classified and coded according to its actual set of main characteristics and any number of attributes. Figure 2 shows an example of part classification. The user will in an interactive session traverse the ac- tual classification tree and select the geometrical, functional or other characteristics relevant for the actual item. The easy accomodation of any classifica- tion scheme allows the user to develop his own and a- void the use of the more universal schemes where the user only utilizes a fraction.

Once having classified the existing parts, process capabilities, production equipment, materials, too- lings etc. the stored information can be utilized in

1111.1

Figure 2: Example of part classification system supported by DCLASS ( 6 )

- Design or information retrieval - Family information search - Database statistics. 3. Generative process planning

The ability to automate (partly) and to improve qua- lity and consistency of decision making and solu- tion specification in design and manufacturing engi- neering are real challenges especially in relation to CIM. This will include capture and utilization of ex- perience and know how accumulated in the specific company. implementation and utilization of company policies, standards and handling of decision rules. For example material and process selection can be linked into design.

An automated approach for generation of complete, in- dividual and specific solutions of problems within well defined areas can be developed based on DCLASS. Examples are generative process planning, tooling sy- stem specification (51, mechanical or electrical as- sembly planning.

Figure 3 illustrates (simplified) the concept of de- cision making. A set of keywords (any number) are triggered automatically when the user interacti- vely defines the actual requirements (in the specifi- cation/requirement tree) and these keywords (flags) will match another set of keywords defining the solu- tion/plan/action from the solution/plan/action tree. Many trees may he involved in the solution genera- tion. Figure 4 shows the architecture of a generative pro- cess planning system.

In Figure 5 is shown the output of the process plan- ning. Having interactively specified the actual part according to geometry, dimensions, tolerances, form features etc., the system will automatically select machine tools, processes, specific operations with sequencing, data, tooling and eventually time calcu- lations. It should be noted that the process planning system is very flexible i.e. it can easily be expan- ded/modified to meet company specific requirements with respect to actual part characteristics and mac- hine tools/processes operations/toolings etc. as well as specific decision logics, standards etc.

DECISION MAKINO BIT . I 1

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DCLMB - ImmAmIvE PART IIlcIFIcATIm -TIC ~ 1 9 1 0 8 ov Lm! OT K E I . O R l b

Figure 3: Concepts lsimplifiedl of decision making support, ( 7 )

4. Automated part family design and manufacture Many components in industry can be handled in part families where completely automated procedures from specification to production can be developed. In the

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Figure 4: Architecture of generative process planning ( 8 / 1 1 )

example shown (Figure 6 ) DCLASS has been built into a CAD/CAM system. The procedure starts with a systema- tic specification oE the component through an inter- ractive session. Simultaneously the component is displayed for visual evaluation and automatic classi- fication updating the database. The modelling sta- ge is fully computer supported i.e. every user selec- ted dimension is checked against a tool/equipment da- tabase, similar or identical components may be ret- rieved, designer chosen features are checked €or sui- table tools/equipments, and the economical consequen- ces of selecting a tool/equipment which is not i n the database are indicated. Finishing the modelling stage a process plan is automatically generated indicating

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Figure 6: Output example of generative process

in the right sequence,which processes, operations, tools should be selected in order to produce the com- ponent. Besides an NC path based on the process plan is generated and stored in the cutter location file (CL).

The potentials of using DCLASS as a key software for system integration is tremendous. Computer memory space required is minimized as it is not necessary to store files containing graphics, process plans and NC-paths. All information and logics are contained in DCLASS trees as bit strings from where it easily and quickly can be generated. The DCLASS trees are based on company standards and policy and can easily be up- dated or modified.

planning

5. CIM-Miniature Laboratory (CIM-MLI

In a joint research program between Brigham Young U- niversity (Prof. D.K. Allen), Bradley University (Prof. G. Olling, now Chrysler Corporation) and Tech- nical University of Denmark a CIM-ML is being develo- ped €or research and education.

The goals of the CIM-ML research are:

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Figure 7: Part family design and manufacturing nodule

- Establishing a prototype CIM-system based on rele- vant hard- and software elements to be used in re- search and development within computer support of engineering functions, hard- and software integra- tion, software development and testing

- Applications concerning simulation of FMS/CIM sy- stems, training of personnel within CNC. FMS and CIM, and test production

- Education of engineering students, management stu- dents, technical assistants etc.

The term "mini" applies primarily to the size of the hardware,here small table-top (but industrial) machi- ne tools and robots are used. This saves a large in- vestment and running costs. Standard controls for the commercial equipment are used.

The software is full scale and is running on IBM PC's(XT/AT). The standard or basis software used in- cludes DCLASS, Database Management, Networks, CAD/CAM system, and a real time basic operating system.

6. Conclusion

The paper describes implemented computer based sup- port modules for carrying out a number of engineering functions and methods of integration of these into CAD/CAM systems and CIM. It also provides a survey of the research and development at the Institute of Ma- nufacturing Engineering.

The main philosophy has been to develop concepts for decision making etc. for different main functions and not to provide canned solutions. With a workable con- cept the industry will tailor its own final solutions since nobody except the company can supply the deci- sion structure, company culture, data etc.

The research and development line sketched in this paper focuses on engineers carrying out their profes- sion on an expert level which is a prerequisite for good solutions.

References

( 1 ) Allen, D.K: Computer Integrated Manufacturing, BYU, M.T.533 Course Material

31 9

(2) Allen, D.K: Impediments to Implementatioin of the CAM-I Long-range Plan CAM-I, 1984 (Obtained from Prof.Al- len 1

( 3 ) Jsrgensen, J. 6 L. Alting: A General and Flexible System for Information Handling and Decision Making. AUTOFACT EUROPE Conference Sept.24-27, 1984, Switzer- land.MS84-622.

(4) Jacobsen, P: Computer Integration of Design and Manufacturing. Ph.D. Thesis, Technical University of Denmark, 1983, 141 pp.

(5) Jepsen Jensen, L: Computer Aided Tool and Die Design. Ph.D. Thesis, Technical University of Denmark, 1984. 146 pp.

Material, CIM-Consulting ApS, In- dustrivenget 37, DK-3400 Hillersd,DK

( 6 ) - DCLASS Brochures and Information

(7) Jacobsen, P. 6 Jargensen, J: Application of Tree Processing Software Tools IPU, 1985 Technical University of Denmark, AP85.

(8) Lenau, T: Expert Systems - Knowledge Engineering Current Ph.D research program Technical University of Denmark

( 9 ) Christensen, S.C. 6 M.Als Pedersen: CIM-Minilab Current Ph.D research programs Technical University of Denmark

tion Systems Current Ph.D. research programs Technical University of Denmark.

( 1 0 ) Bilberg, A. 6 N.E. Larsen: Simulation of Produc-

( 1 1 ) Jsrgensen, Alting, Jacobsen, Jensen, Christen- sen, Christiansen, 6 Lenau: FRAMEWORK of Engi-

neering, Application Modules, IPU Tech- nical University of Denmark.