Product-process integration: design of a production

Product-process integration: design of a production system for mass production Patrick Martin, Alain D’Acunto, Janique Arzur, Laurent Abt Laboratoire de Génie Industriel et Production Mécanique (LGIPM) (Production Engineering and Mechanical Production Laboratory) ENSAM – Technopole 2000 – 4 rue Augustin Fresnel – 57 078 Metz cedex [prenom.nom]@metz.ensam.f In a context of integrated mechanical design and manufacture, these approaches and applications are well known at both academic and industrial level. Production constraints must be taken into account at the same time as economic, logistics or legislative constraints. Facts and constraints must therefore be structured, formalized and represented. In this article, we present a procedure for the design of a production system for mass production, based on part modelling and formalization of technological knowledge using production features. The constraints of antecedence or simultaneity are formalized using temporal logic. Systems architectures are deduced by assessing execution times and conditions of accessibility. Finally, multi-criteria analysis is used to calculate the cost and reactivity constraints of the final choice. ABSTRACT

(NDT: votre résumé a été traduit du français vers l’anglais, car l'anglais ci-dessous n'est pas tout à fait le même texte et a de toute façon besoin d’être relu et corrigé) ABSTRACT .

In the frame of integrated design and manufacturing in mechanical engineering the design of the parts, the process planning, even the production system must be made quite simultaneously. So the design and development cycle is reduced and the manufacturing constraints are taken into account as soon as possible. In order to give an illustration of this wide problem we will present here a case of application for elaboration of the production system in mass production. Parts are defined par using manufacturing features, temporal logic allows to described simultaneous and anteriorities constraints, the system architecture is deduce, and finally multi-criteria analysis allows to choice the final production system. : système de fabrication, entités, ingénierie intégrée, intégration produitprocess, grande série. KEYWORDS

KEY WORDS:

production system, features, concurrent engineering, product-process integration, mass production.

Article selected following the CPI’2001 conference: 24-26 October 2001 in Fès

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1. Introduction 1.1. Study context The common objective of companies today is to be competitive in terms of cost, reactivity and quality in a context of market diversification and fluctuation, globalization and increased competitiveness. Within this framework, relative to mechanical engineering techniques, one answer is in design and concurrent engineering (integrated, concurrent, simultaneous, process engineering…) which uses concepts, approaches and applications which are well known at both academic and industrial levels [SOH 92 ,TOL 98]. By process, we mean processes (forging, casting, stamping, machining, assembling, fast prototyping..), production resources (machines, tools..), conditions for implementation (setting and holding in position, operating conditions…), operation scheduling and the structure of the installation. Production constraints (process, capability, producible shapes, precision...) must be taken into account at the same time as economic (cost...), logistics (lead-times, reactivity, size of production runs.. ) or legislative (recycling, safety..) constraints. On the one hand, knowledge and constraints must be structured, formalized and represented (data and processes), using experimental data (processes and resources) and models of industrial conditions so that different types of expertise can be coherently integrated using appropriate models, methods and tools so as to meet production optimization objectives (quality, reactivity, productivity, cost…). This concept is illustrated in figure 1: the quality of mechanical parts depends on the expression of specifications (shapes, functions, dimensions, surface quality, materials), the ability of shaping processes and resource capability (defects in machine-tools, tools, machinery). To meet optimization objectives, models and processes are used to generate production processes or design production systems or to validate a product's producibility, as well as defining the product qualification procedure. 1.2. Study objective Here we are interested in developing a production system which constitutes a specific, but unique product. It must mass produce products which are in the same family but which may evolve according to technological development or market demand. A great deal of work is being done on production system design, but is mainly concerned with logistics aspects (installation, scheduling) based on technical and temporal data (sequences, times, production resources) provided by the methods department. Work on designing the operative part of production systems is still limited [GAR 92, JAC 92, LOS 97, PRU 93]. We therefore propose to draw up a methodology to help in defining flexible production architecture for use in mass production machining with the intention: - of integrating the manufacturer's expertise based on a grouping strategy using production features;

Mass production manufacturing system

3

- of integrating "flow shop" type linear mass production; - of making it possible to formalize concepts by including productivity, cost, flexibility and quality parameters. Objectives: quality, precision, reactivity, global optimization Constraints: economic, societal.. Product: structure, functions, material, shape and surface

Process: machining, rectification, forging, stamping, casting, rapid prototyping …

Models, methods, tools: Modelling, representation, simulation, experimentation

Production process Test procedure Equipment Producible parts

Resources: machines, equipment

Figure 1. Reference diagram of "Product/Process" integration The selected architecture must meet (figure 2): - technological requirements needed to produce each machining feature (respecting surface condition, geometric and dimensional tolerances) and equipment capability (precision, torque, power, speed...); - economic constraints; - logistics requirements: quantity, series, lead-times; in a coherent approach based on a methodology, models and tools.

4 definition drawing technical specifications geometry dimensions material

PART

support flanging accessibility shape FEATURES topology relations between features precision

power torque capability limiting parameters production capacity type of operation material machined constitution dimension costs size of run repeatability time

technical constraints

MACHINE

EQUIPMENT

economic and logistic constraints

evaluation criteria production process Drawing up a part production process production process processes resources precedence determination of bearing surfaces

knowledge

part performance tool performance process model optimization calculation

models tools


Figure 2. The basic elements of production system design

5

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2. Proposed methodology 2.1. Procedure The different phases in the procedure and the associated tools or methods are presented below (table 1). PROCEDURE COMPONENTS TOOLS - METHODS Phase 1: Analyze the part - Define part fitting

Definition drawing

(drawn up during the design phase)

Identification of the bearing surface

- Analyze tolerances

Put the part in isostatic position

- Analyze productivity constraints Phase 2: Identify the machining features - Identify the types of features

Expert assessment

- Define the geometrical relationships

Analysis of the feature's intrinsic characteristics

- Define the topological relationships

Knowledge of the 7 main relationships

- Localize the features

Matrices in homogeneous coordinates

- Define the lists or sequences

Relationships with precedence or simultaneity defined by temporal logic

Phase 3: Choose the types of movement per feature - Identify the directions of accessibility

Characteristic polyhedron

- Visibility problems

Gauss sphere

- Definition of type of movement per feature

Paraxial / positioning / fixed / continuous path control / ½ axis

Phase 4 : Choose the machine architecture - Estimate movement and operating times

Calculation of cutting time, timing

- Suggest an architecture

Temporal logic

- Determine configuration

Helgeson & Birnie's method, Flux simulation

Phase 5: Choose the equipment - Choose the operative part equipment

Equipment database

- Choose activators and the control part

Database, technoguide [ADE89]

- Assess investment costs - Estimate production costs Phase 6: Estimate the quality and precision of the parts obtained - Take into account the actual machine geometry

Matrix with homogeneous coordinates

- Take positioning faults into account

Small movement wrench

- Check accessibility

Digital simulation

Tableau 1. Presentation of stages of methodology


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We shall not deal with the entire procedure in detail, but will concentrate on the important tools or models, using an industrial example of mass production (camshaft bearing cap case, figure 3). First of all, the feature, temporal logic and ADEQUA method are presented.

VIEW FROM BELOW (Face culasse)

VIEW FROM ABOVE (Face couvercle)

Figure 3. Camshaft bearing cap case 2.2. The idea of a feature Product manufacture must simultaneously meet design and production requirements (processes and resources). The description of the part and of the production process is defined via the concept of a feature (feature, characteristic) [GAM 90, GAM 99, SHA 94, TOL 98]. A feature is a semantic group (modelling atom) characterized by a set of parameters, used to describe an object which cannot be broken down, used in reasoning relative to one or more activities linked to the design and use of products and production systems. The objective of modelling in features is to facilitate: - the formalization of expert assessment; - the capitalization of expertise; - to provide information about production activities very early in the design phase; - to improve communications between people working on the product throughout its life cycle. This concept uses a high level of semantics, but the functional-feature – machining-feature link is not necessarily one-to-one. A universal catalogue of features cannot be envisaged because it depends so heavily on the industrial

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context. Every company, depending on its needs and habits, needs more than one baseline catalogue [VIL 90]. Features are characterized by a set of information: - intrinsic characteristics: dimensions, surface condition, tolerances of the feature's own shapes; - geometric relations between features: dimensions, geometric orientation tolerances, geometric position tolerances; - topological relations: proximity or interaction relations. After identifying the types of features we must find the position of each of them relative to the initial part position. Each feature has an associated local identification, the position of which, relative to the part position, is defined by the matrix with homogeneous coordinates (4x4). The 12 terms which are non null or equal to 1 characterize rotations and translations in offset G i and movement Mi [MER 97]. For small deviations Ddi or kinematic faults Dmi, the matrix terms can be linearized. This matrix-linked notation is routinely used and found to be an efficient mathematical tool which can easily be manipulated in formal calculations tools, such as the "mathematica" software. Positioning of the part feature on one hand and the tool on the other can be directly calculated by a product of matrices (open chain of solids, figure 4), the terms for machining being written by the identity of the 12 terms of the two matrices (equation [1]) for passing from frame to feature and frame to tool:

[ O | E ]  [ O | T] with [ O | n ] = 1 , n G i-1 * Dd i-1 * Mi * Dm i

[1]

Knowing the positioning faults as well as those of production resources, the tolerance zone for positioning the tool can be determined. Ps2 2

Configuration 1

Ps23 Ps1 2

Ps11 Baseline 2

Baseline3 Ps13

Ps2 1

Configuration 2 Baseline 1

Configuration 3 Ps31

Part baseline

Figure 4. Determination of the feature identification (Référentiel = Baseline, Référentiel de base de la pièce = Part baseline)


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2.3. Temporal logic Two algebraic structures are used [GAR 92]: - the 1st structure is named (P). It is assigned classic logic operators: : OR, : AND, W: OR exclusive - the 2 nd structure is named (O), it is an extension of (P) with temporal connectors M, S and is used to introduce the constraints of precedence and grouping: - S ( ) indicates that the terms in brackets are produced simultaneously (staged or associated tools, spindles working simultaneously on a single part); - M (A) indicates what to expect to make A. This algebra is used to obtain a formal representation of the production line configuration used to produce a part or a set of parts defined by their features, and to deduce the set of part types which can be produced on this line, thus meeting the objective of part type flexibility. The line consists of machining modules with 0 to 3 degrees of freedom in positioning, in paraxial or continuous path control. 2.3.1. example 1 - S (AB): indicates that A and B can be made simultaneously e.g. drilling and spot facing done by the same tool (staged tool) - A  M(B): indicates that B is made after A e.g. tack welding, then drilling - A W B: means that feature A or feature B is made exclusively. - A  B: A and B can be made in any order. 2.3.2. example 2 To define the configuration of a production system for making parts P1, P2, P3, P4, - the operations to be performed per part are: P1: O1, O2, O3; P2: O1, O4, O5; P3: O1,O5; P4: O2, O3; - possible operational grouping (associated tools) are: O1, O2, O4 on the one hand, O3 and O5 on the other; - precedence constraints are: O1 then O5, O2 then O3 (to make O3 you must first have made O2, to make O5 you must first have made O1). Equation [2] describes the composition of production modules composing the lines and equation [3] the four line configurations taking into account the constraints of precedence and simultaneity (multiple tools): EQ 1 = (O1  O2  O3) V (O1  O3  O4  O5) V (O2  O5 ) V (O2  O3)

[2]

CONF 1 = [S ( O1  O2 )  M (O3) ] V [S ( O1  O4 )  M S ( O3  O5 ) ] V [ O2  M (O5) ] V [ O2  M (O3)] [3]

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i.e. 4 lines in parallel, 8 modules (using associated tools), 7 types of parts possible: O1  O2  O3, O1  O2, O1  O4  O3  O5, O1 O4, O2  O5, O2, O2  O3. By calculating degradation [2], equation [4] is deduced as well as the line configuration [5] to produce the four parts. EQ 2=> [( O1 V O2)  O3] V[ ( O1 V O2)  O4  (O3 V O5) ] => ( O1 V O2)  O4  (O3 V O5) [4] CONF 2 = [ O4  (O1 W O2 W S ( O1  O2 ))]  (O3 W O5 W S ( O3  O5 ))] [5] i.e. 1 line, 5 modules and 25 types of parts possible 2.4. ADEQUA (Aide à la DEcision de QUAlité) (Aid to quality decision) Method. This will enable us to choose the equipment. ADEQUA was developed in 1950 by Zimmerman, an American and NASA executive, and provides a procedure for exploring information adapted to every type of situation. A Prior Analysis of the Situation provides an initial situation: the facts which pose problems are the subject of an action defined to solve the problems. It provides the means for identifying and processing useful information which is essential to the quality of problem processing and hence the quality of the solution found. For our study, we have a choice to make in order to reach a goal. The stages to be completed are given in table 2. Note that the destructive criterion will immediately eliminate a possible solution if it does not meet the criterion's requirements. The selective criterion is given a weighting determined by joint agreement of the working group, made up of experts in the field in question. This will be based on the inventory (list which is as exhaustive as possible) that the working group will decide on if a criterion is selective or destructive, or can be grouped into a given category.

PERCEPTION DESCRIPTION

Goal to reach Component of the goal Destructive and selective criteria HYPOTHESES Possible options CONFRONTATION Test on criteria from PO to PRO (POssible to PRObable)  PRO-OP (PRObable OPtion) Risk analysis before decision from PRO to PROV (PRObable to PROVed) Actions to reduce risks SOLUTION Choice proved (recommendation)

Tableau 2. Stages in the ADEQUA method


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3. Designing a flexible production line for mass production 3.1. Phase 1: Part analysis This analysis is classic in production analysis [HAL 95]; note simply that: - certain bored types of features are machined once the part is assembled on the cylinder head; - some machining operations, notably involving milling, can be performed on both casings during the same operation. The part is fitted onto the pallet either on plane P (cylinder head side), or on the opposite side: plane F2 (cover side). Part flanging is determined so as to remove any risk of the part overbalancing or sliding, while avoiding the risk of deformation due to the force applied. When analyzing dimensional tolerances, it is noted in general that 0.2  IT  0.5, and that we also have 2 H8 holes. It is therefore not a problem to respect tolerance intervals on dimensions for routine machining processes. The geometric figures specify position tolerances (localisations) which also remain within normal values. The specified roughness concerns two planes with a polygonal edge (including plane P). The function applied to the surface is a static tightness (without seal) for a fixed assembly with a roughness of Ra 0.8 m obtained by flat rectification. 3.2. Phase 2: identification of machining features The set of features to be machined, their types, intrinsic characteristics, topological relationships and associated basic processes are grouped in table 3. The location of each in the part position is also defined. 3.3. Phase 3: choose the types of movement per feature Table 4 gives the associated operations, precedence relationships expressed in temporal logic and possible directions of accessibility for each feature. For each degree of freedom possible for each machining module used for machining operations, the type of movement is specified (F: fixed, B: stopped, PT: positioning, PX: paraxial, C: continuous path control); it is directly linked to the choice of components (kinematic, motorization..) and hence cost.

12

Identification

P

F2

Feature

Geometric relationships

Topological relationships

Operations

Flat surface without

21.1Ø0.5 T3

E (rough)

edges

13.1Ø0.5 T4

F (finish)

455x90 Ra 0.8

35 F2


35 P

E

edges

F

455x90 Ra 0.8

F3


48 0.2 D2

F

407 0.2 D2

F

edges Ø 64.5

F4

Flat surface without edges 115x35 Ra 0.8

D1

Smooth through hole

24Ø0.5 CH1,AL1,AL2

Starts_on P

F

Starts_on P

F

Starts_on F2

F

Ø 7+0.2 L=22.5

D2

Smooth through hole Ø 10 / 14 L=35

D5

Spot-faced through hole

48 0,2 F3 407 0,2 F4 26Ø0,5 CH1,AL1,AL2 5Ø 0.7 M F2

Ø 11  0.1 L=5

Ø 0.7 M CH1,AL1,AL2

Tapped blind hole

36.,6Ø0.5CH1,AL1,AL2

M6x1 L=19

2.,5Ø0.5 P

Tapped blind hole

46Ø0.5 CH1,AL1,AL2

M8x1.25 L=16

13.1Ø0.5 P

Tapped blind hole

48.5Ø0.5 CH1,AL1,AL2

Starts_on F2

F

Tapped blind hole

31Ø0.5 CH1,AL1,AL2

Starts_on F2

F

M6x1 L=16

30.9Ø0.5 CH1,AL1,AL2

Flat bottom bore

Starts_in_

F

Ø 50 H8 L=9

coaxial CH1

Through bore

Starts_in_

E

Ø 30 H8

coaxial AL1

F

Inner bevel

Starts_on F3

E

T3 T4

T6

F

Starts_on F4

F

M6x1 L=19 T7

AL1

AL2

CH1

0.6 x 60°

Tableau 3. Table of features


Features Peb Pf F2eb F2f F3 F4 D1WD2 D1M(D2) D3M(T3) D4M(T4) D5 (D6M(T6))W (D7M(T7)) S(D6D7) S(T6T7) AL1 AL2e AL2e AL2f CH1 CH1M(AL1) CH1M(AL1) M(AL2f)

Machining operations

13

Direct° tool axis 6 2W5 6 2W5 1 2W5 1 2W5 3 1W6 4 1W6 1W6 1W6 3 4 1 1

Mvt X axis

Mvt Y axis

Mvt Z axis

Direct° access.

Face milling Slab milling Face milling Slab milling Face milling Slab milling Face milling Slab milling Face milling Slab milling Face milling Slab milling Drilling Drilling Drilling/Tapping Drilling/Tapping Drilling Drilling/Tapping

Antecedence relationship s _ _ F2fPéb F2fPéb Péb Péb F2ébPéb F2ébPéb Pf Pf Pf Pf PfAL2e PfAL2e AL2e F4AL2e F2f F2fAL2e

PX PX PX PX PX PX PX PX PT PT PT PT F PT PX PX F F

PT PT PT PT PT PT PT PT PX PX PX PX F PT F F F PT

F F F F F F F F F F F F PX PX F F PX PX

ZZZZZ+ Z+ Z+ Z+ X+ X+ XXZ Z X+ XZ+ Z+

Drilling/Tapping Drilling/Tapping Boring Milling blank Boring blank Finish boring Bevelling Bevel/Boring CH1/AL1/AL2f

F2fAL2e D6D7 CH1 Pf Pf AL2eAL1 F3 F3 F3AL2e

1 1 3 6 3 3 3 3 3

F F PX PX PX PX PX PX PX

F F F F F F F F F

PX PX F PT F F F PT PT

Z+ Z+ X+ ZX+ X+ X+ X+ X+

Tableau 4. Table of antecedence relationships and directions of accessibility 3.4. Phase 4: choosing the production system architecture 3.4.1. Estimate of machining time These times are the sum of technological and auxiliary times. Technological times are calculated from cutting conditions defined using standard software (tool-material torque) and take into account the possibilities of simultaneous machining to obtain a baseline for technologically feasible minimal times. Auxiliary times are estimated by timing or analogy: - rapid movement (approach, return, remove tool) = 1.5s - changing tool with revolving turret = 1.5s - station to station transfer = 3s - automatically turning the part = 4s

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- brushing the part: automatic = 3s - loading / unloading: automatic = 1.5s, manual = 12s 3.4.2. Determination of machine loads Each part goes to a workstation and is subjected to one or more operations, then passes on to the next synchronously. To optimize productivity, workstations must be balanced by grouping operations on the one hand and defining the operations to be performed at each workstation on the other, to guarantee production (number of parts per unit of time) which is part of the input data when there is a problem. To balance the production line we use the Helgeson and Birnie method. We want to produce 1280 parts per day; a working day with two shifts represents: 2 x 7.5 x 3600 = 54000s; the cycle time or time allocated to each workstation is thus 42.2 s/part. Therefore, based on antecedence and according to technological time required by the various machining operations, we see that, in a first analysis, we were able to group these operations on 5 machining workstations (figure 5). However, we still have to refine and validate these groups, taking into account installation of the part and turning operations needed as well as accessibility problems. It is only then that the workstation installations will be fixed and machine loads can be determined. The number of parts actually produced per unit of time can then be estimated. Based on machine loads, we can determine actual daily production: - the cycle time is the longest time of the 5 workstations: 38.4 s + 3s (Ttr) = 41.4s - daily production is therefore:1304 parts per day - technological time is 142 s and the time to produce one part: T = Tt + Ts + Tmd = 142 + 12 + 1.5 = 155.5 - the total time spent by one part on the lines is: 5 x 41.4 = 207s - the efficiency is thus: 155.5 / 207 = 75% 3.5. Phase 5: choosing the equipment In the light of what we have revealed so far, several line architectures could be recommended to give a satisfactory productivity/flexibility/cost compromise: - "classic" linear transfer line consisting of special machines (solutionA); - linear transfer line consisting of machines with modular components (solutionB); - linear transfer line consisting of high speed CNC machining units (solutionC).


FLUX A

Unloading

34.5 s

AL2f

FLUX B bearing on Pf

Unloading

AL2f D5

Ttr=3 s D2 T4 T3 T6 T7 D1 D4

36 s

Ttr=3s D3 D6 D7 AL1 D5 F4

38.4 s

Ttr=3 s bearing on Pf

T3 D3 D2 AL1 CH1

28.9 s

Taking into account fitting and accessibility gives the reorganization of flow labelled FLUX B

30.9 s bearing on F2f

Ttr=3s

T4 D4 F4 D1 Pf

26.1 s

Ttr=3s Ttr=3s

AL2e CH1 F3 Pf F2f F2eb

36.6 s

bearing on Peb

T7 D7 T6 D6 F3 F2f F2eb

Assembl y

17.5s

33 s

Ttr=3s

Ttr=3s

Peb

bearing on F2raw

15

AL2e Peb Assembl y

Figure 5. Results of the Helgeson & Birnie method

29.1s

16

During this phase the working group must sift through all the criteria judged to be useful, as exhaustively as possible. For our application we shall note the following: - number of spindles, - number of axes, - spindle power - spindle rotation speed, - tool orientation capacity, - speed of axis movement, - travel, - rigidity, - precision of guidance,

- precision of positioning, - dimensions accepted, - machinable materials, - tool flexibility (per part) - operational flexibility, - production system flexibility.

Tests on ADEQUA method criteria are given in table 5. DESTRUCTIVE CRITERIA Production costs < 700 000€ Spindle power  7.5KW Dimensional capacities > 600mm³ SELECTIVE CRITERIA Greatest possible flexibility Greatest possible spindle speed and torque As many accessibilities as possible Greatest possible rigidity Greatest possible speed of axis movement The longest possible travel Greatest possible guidance precision Greatest possible precision of axis positioning Greatest possible reliability / strength Simplest possible maintenance

A yes yes yes

POPRO confrontation B C yes yes yes yes yes yes PROPROV confrontation N*P N N*P N N*P 24 9 108 7 84 91 5 65 10 130

Weighting 12 13

N 2 7

11

6

66

6

66

8

88

9 12

9 7

81 84

7 7

63 84

7 10

63 120

8 9

8 7

64 63

9 7

72 63

6 7

48 63

10

6

60

8

80

8

80

9

8

72

6

54

7

63

7

6

42

9

63

6

42

TOTALS

647

718

781

Table 5. Tests on destructive and selective criteria There are two solutions which are very close to each other. Appendix 1 develops all the criteria. In this case, either the leading solution is selected or the influence of a change in scoring a weighted criterion can be tested for the two rival solutions. To validate the PRObable choice and turn it into a PROVed solution, an application risk analysis is performed to reach a decision on whether risks are acceptable or not.


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4. Conclusion We have presented a method for designing production systems, consisting of six phases, which is part of a product-process integration procedure: - Analysis of parts - Identification of machining features - Definition of machining and movement components - Choice of architecture then equipment - Validation of probable solutions - Test change to a proved solution Each of these phases includes a certain number of precise points which are necessary for successful use of the method, to reach our final objective, embedding technical, economic and logistics aspects as far as possible. We had to meet these objectives in order to be able to define an integrated production line architecture (and the equipment it includes), while providing the best compromise between cost, productivity, quality and flexibility parameters. This type of methodology, to which simulations of kinematic or dynamic performance of the equipment and flow can be added, provides a tool to aid in decision making for process engineering, thus helping reduce the time and cost of production engineering. 5. Bibliography [ADE 89], ADEPA, Technoguide E, le guide de la commande d'axe, éditions ADEPA, March 1989. [GAR 92] GARRO O., Conception d'éléments physiques de systèmes de production, University of Nancy thesis, May 1992. [GAM 90] GROUPE GAMA, La gamme automatique en usinage, 1990, Hermès. [GAM 99] GROUPE GAMA, Ingénierie simultanée : conception des processus de fabrication, Université d’été, ENS Cachan, 5-9 July 1999 [HAL 95], HALEVI G., WEILL R., Principles of process planning, Chapman and Hall 1995. [JAC 92] JACOBE P., Génération ascendante de gamme d'usinage: proposition d'une méthode appliquée aux travaux de très grande série utilisant des machines à transfert circulaire, University of Franche-Comté thesis - 16-12-92. [LOS 97] LOSSENT L., Contribution à la conduite d'étude de faisabilité de systèmes de fabrication, University of Nancy thesis 1, 20-10-97. [MER 97] MERY B., Machines à commande numérique, Editions HERMES., 1997.

18 [PRU 93] PRUVOT F., Conception et calcul des machines-outils – volume 1, Presses polytechniques et universitaires romandes – October 1993 [SHA 94] SHAH J.J., MÄNTYLÄ M., NAU D.S., Advances in Feature Based Manufacturing, (Editors), Elsevier Science (publisher), 1994. [SOH 92] SOHLENIUS, Concurrent engineering, Annals of the CIRP, pp.645-655, vol.41/2, 1992. [TOL 98] TOLLENAERE M. (sous la direction de), Conception de produits mécaniques, modèles et outils, Editions HERMES., 1998. [VIL 90] VILLENEUVE F, Génération ascendante d’un processus d’usinage. Proposition d’une formalisation de l’expertise. Application aux entités d’usinage, Doctorate at the "école centrale de Paris", February 1990.

Annexe 1: Tableau récapitulatif des différentes informations utiles propres aux trois types d'architectures envisagées INVENTAIRE DES PARAMETRES COUT / FLEXIBILITE / PRODUCTIVITE / QUALITE

solution B

solution A

Solution C

XX

P R O D U C T I V I T E

C O U T S

P broche (KW) N broche (tr/min) Vitesse rapide (mm/min) Acc (m/s²) Courses (mm)

axes X,Y axe Z axes X,Y axe Z axes X,Y axe Z

Condit° de coupe

Coûts d'investissement (HT) Outillage / divers

FIABILITE

FLEXIBILITE

Formation maintenance

YY

Unités d'usinage

Unités de perç./tar.

0,4 24000

50

Unités de fr./alés.

Unités de perç./tar.

0,37

0,55

7500

3000

80

Unités de translation

ZZ Unités de translation

CU2

CU4

0,75

25 à 40

5 à 15

22

33

3000

15000

15000

16000

10000

60000 60000 7à10 7à10 500 550

30000 30000 3 3

75000 75000 1 1 630 600

10000 100000 1 1 1600 500

20000

50 à 10000

630

120

18189

13878

67850

15220

19030 (pneum)

1,5 à 4 MF suivant modèle

3,5 MF environ

Unité de production flexible 3 axes = 297800

broche à tête multiple

Renvoi d'angle pour MAX3 (TR3) = 14411

300 à 500 KF

Tête révolver ETR6 = 93482

Tête révolver TRB25 = 85850

technologies, mécanique connue

Remplacement standard avec module en stock

Formation nécessaire / changement des habitudes

Avantages ou inconvénients liés à la technologie de la machine

Les éléments modulaires ont la particularité d'être des éléments standards du commerce Contraint permettant de réaliser une architecture de machine particulière. Leur compatibilité due à leur Flexibilité Mat.(ALU)Vo conception leur permet d'avoir une capacité de réactivité quant à un changement important totale matière et lume (2 pièces intervenant sur la pièce (changement de cotes, d'accessibilité des entités, etc.) Chaque broche pièce de 250mm3) est néanmoins étudiée pour une application particulière en terme de conditions de coupe.

Configurations ou options possibles

Têtes à broches multiples Plateaux diviseurs Têtes révolver avec têtes à broches multiples embarquées

Limites quant aux domaines d'applications

CU5

3 à 7 fois les conditions de coupe "traditionnelles)

inférieures à UGV

coûts d'étude et de réalisation élevés (unitaire)

ZXY

CU1

L'assemblage des différents modules peut parfois donner une cinématique imprécise et une architecture insuffisamment rigide. La durée de vie du système et la qualité du produit fabriqué s'en trouvent alors amoindris. En ce qui concerne les coûts, reconstruire une machine spéciale en utilisant des éléments modulaires reviendrait très cher. Ces modules sont donc plus adaptés à des déplacements sur un ou deux axes, suivant un cahier des charges qui, malgré tout, fixe des limites à ce type d'architecture.