2. Faculty of Mechanical Engineering and Naval Architecture Development of a System for Concurrent Engineering Assembly Plan Generation Zoran KUNICA, Ph.D., Assistant Professor Professor Božo VRANJEŠ, Ph.D. Miljenko HRMAN, B.Sc., Postgraduate student -- trainee University of Zagreb Croatia Section: ISMS 2001: Processes and Systems Third International ICSC-NAISO WORLD MANUFACTURING CONGRESS April 2-5, 2002, Rochester, New York, U.S.A.

3. INTRO The most of the products have more than one part... so they must be assembled. The goal of the research: development of CAE component that would allow more efficient assembly planning in the effort to integrate: the product design, assembly system design. The motivation of the research: upgrading the assembly system planning methodology, development of the computer support for planning. Recent explorations: the necessity of assembly and assembly-related knowledge synthesis, compilation and integration (concurrent engineering); automatic vs. interactive process/system generation; variants and combinatorial complexity; shift of interest to still uncovered aspects of the human process planning, which is intuitive to a great extent. 2

4. 3 The Production PILOT, still developing suite of products, consists of assembly process design, simulation, and analysis tools, built into 3-D graphical environment, and seems to be good example of future trend of development and practice (SILMA, 2001).

5. ASSUMPTIONS 4 Assembly process/system planning  a product -- an assembly, exists as CAD model  assembly and disassembly are inverse issues  a product is a virtual mechanism, that should be recognized during planning stage  an assembly system is a complementary mechanism non-standard components PRODUCT (ASSEMBLY) ASSEMBLY SYSTEM standard components mechanism I – assembly paths mechanism II – components` motions

6. PLAN GENERATION SYSTEM & ELEMENTS5

7. SOME PLAN ELEMENTS For an automatically generated initial disassembly sequence, instead of the criterion distance of the part centre of gravity from the product centre of gravity, the combination of three criteria is used: distance of the part centre of gravity from the product centre of gravity, the value of y component of the part centre of gravity, part volume (mass). 6

8. One criterion... The improved alghorithm – three criteria... The example of advantages of using combination of criteria for initial disassembly sequence... the main part 7

9. The sequences of assembly operations regarding part position, assembly stability and assembly orientation and position If the assembly is unstable, it should be lifted. The value of lifting is defined by the value of R in direction of +y axis. Normal part position is the position of the part in the upper part of the interference sphere around the product. Lower part position is the position of the part in the lower part of the interference sphere around the product. Normal assembly orientation comes from initial product orientation. Rotated assembly orientation means that the assembly is rotated 180  around the x-axis that passes through assembly centre of gravity. Projection of the part is the rotation of the part (the part centre of gravity) by 180  around the axis in the xz plane that passes through the assembly centre of gravity. “Project the part” occurs if the assembly is rotated. “Project the part” is not a real assembly operation but a planning operation. 8

10. EXAMPLES OF PLAN GENERATION 9

11. DEVELOPMENT OF THE ASSEMBLY PLANNING SYSTEM An assembly planning environment should combine tools distributed in two levels: 1.pretools within activities prior to assembly planning, 2.assembly planning CAE component (posttool) that follows product design process. Assembly planning and activities of product design 10

12. Discrepancy in orientation: natural orientation of the part (A), technological orientation (B), orientation required in a product (C) 11

13. Origins of orientation definition 12

14. Example of definition of plan generation parameters ASSEMBLY PLAN GENERATION OPTIONS...... Product class  13 Planning procedure should be analysed as a combination of automatically and interactively generated elements.

15. A concept of the intelligent assembly system development 14 INTELLIGENT ASSEMBLY SYSTEM DEVELOPER PROCESS STRUCTURE DEVICES CATALOGUE standard components OPERATIONS DEVOTER non-standard components SYSTEM INTEGRATOR ADJUSTING OF DEVICE DESIGN

16. Thompson's examples of variations of living organisms (1917) n Variants/variations of products Duerer's examples of variations of living organisms Two solutions of the same mechanism (Blanding, 1999) 15

17. 16 Some of the structures for a product with six parts (Beneath the graphical presentation of each structure the structure’s numerical code is given.) n Variations of assembly process The assembly process can be represented and modelled using generic structures – generic plans. The structures show the space and time possibility of the assembly process realisation.

18. xz – horizontal plane n Variants of product`s initial orientation Hi6Hi5 Hi2 Hi4 Hi3 17

19. n Variants of parts’ layout Rotary-table (D = 1234,212 mm) Line assembly (L = 8639,487 mm). Hi5 Hi4 Hi2 Hi3 Hi6 z distance Hi5-Hi6: 5924,22 mm 18

20. n Treatment of identical parts in a product Disassembled product... Without taking into account identical parts... Taking into account identical (yellow) parts... Savings in space and equipment! 19

21. n Variants of equipment’s manufacturer ABB IRB 14020 FANUC LR Mate 100iLR Mate 100iAdeptSix 300 n Variants... variants... etc....

22. FURTHER WORK Experiments with concurrent generation of assembly plans. Modelling of CE planning situations and roles (procedures, protocols and data sharing). Analysis and optimisation of (dis)assembling paths (directions, lengths). Simulation of assembly operations and assembly techniques (forces, deformable joints - snap fitting,...). Assembly device design and development of a CAD catalogue of devices. Human planner's mental activities and behavior -- conscience and non-conscience (intuitive) aspects of the planning. 21 S. Freud & Eric Berne`s transaction analysis