Production management I (Prof. Schuh)
Lecture 6
Production Management I - Lecture 6 -
Process planning and operations scheduling
Contact: M. Phornprapha, M. Eng.
[email protected] WZL, R. 504 Tel.: 0241-80-27383
© WZL
Objectives of the lecture • To define process planning and to define the boundaries between operations scheduling and operations control • To explain the information media which are created in the process planning department • To outline the functions of operations scheduling • To explain the approach adopted in drawing up operations schedules • To present the tasks and functions in NC-programming • To outline the tasks involved in operations control • To disseminate basic knowledge of scheduling and capacity planning as well as shop-floor control • To characterise the need for action with regard to a rationalisation of process planning • To demonstrate the general approach to rationalisation • To introduce planning methods and tools in order to systematise process planning • To describe areas of application for planning tools
Process planning and operations scheduling
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Production management I (Prof. Schuh)
Lecture 6
Structure of lecture No. 6: 1. Overview of the process planning department
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1.1 Definition of process planning and delimitation of operations scheduling from operations control
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1.2 Information media of process planning
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2. Operations Scheduling
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2.1 Functions of operations scheduling
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2.2 Drawing up operations schedules
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2.3 NC-programming
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3. Operations control
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3.1 Functions of operations control
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3.2 Scheduling and capacity planning
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3.3 Shop floor control
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4. Manufacturing concepts and rationalisation within process planning
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4.1 Planning complexity and new manufacturing concepts
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4.2 Options for rationalisation in process planning
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4.3 Methods for the rationalisation of operations scheduling
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5. Factors impacting on the system used to draw up operations schedules
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6. Appendix 6.1 Supplement
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7. Exercise 7.1 Calculation exercise
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7.2 Self-Calculation exercise
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Process planning and operations scheduling
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Production management I (Prof. Schuh)
Lecture 6
Summary of lecture No. 6 In the process planning department, the manufacture and assembly of the products is thought out in detail and specified, furthermore, the schedules are planned and monitored. The main functions of operations scheduling within order processing are to produce parts lists, to draw up operations schedules, NCprogramming and to plan special-purpose manufacturing resources. Developing the operations schedule involves determining the unmachined part, determining the sequence of operations, selecting manufacturing resources and determining standard times. The results of these planning operations are documented in the work schedule. The data in the work schedule are extremely important since they are required for further use in many areas of the company. Among their other functions, they become part of the so-called ”working papers”. The NC-programming can be regarded as a further detail in the process of drawing up the operations schedule. NC-programs can be written by using various methods, which mainly differ in terms of the location at which the programming is done and of the level of automation involved. One of the long-term functions of operations scheduling is to develop appropriate measures to ensure economically efficient organisation and construction of the manufacturing and assembly area. The main tasks in operations control are to plan the availability of material, to plan schedules and capacities and to control the shop-floor. The duties involved in operations control revolve around the following objectives: - to observe schedules - to minimise the throughput times of material and capital commitment and - to ensure that capacities are fully utilised and that operating resources and labour costs are kept low. The function of scheduling and capacity planning is deadline-oriented planning and control of manufacturing orders, ensuring at the same time that operating resources are utilised to a permanently high level. Short-term control and monitoring of shop-floor orders is the task of shop-floor control. Rationalisation is an important aid for the economic efficiency of production. If operations scheduling is to be rationalised successfully, it is essential to ensure that the rationalisation objectives are at first formulated and that they are then pursued by systematising the organisation, documents, planning methods and tools. The rationalisation objectives have to be identified from an analysis of the company’s boundary conditions and of the requirements to be met by the operations scheduling department. This analysis encompasses the workpieces to be planned, the activities of operations scheduling and the information generated and required. The most important principle of rationalisation is the re-use of planning outcomes already developed. The production and assembly of such parts families can be planned efficiently by using standard work sheets. Operations scheduling uses a number of different tools. The presented systematisation permits tools to be selected purposefully and to be used rationally. Different means of accessing tools selectively will be outlined within the lecture. The rationalisation achieved by systematising operations scheduling and its tools can be further increased by using IT (information technology) -components. An approach to the introduction of IT-components will be presented while pointing out that outcomes achieved in conventional operations are an essential requirement for the successful use of IT.
Process planning and operations scheduling
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Production management I (Prof. Schuh)
Lecture 6
Literature Lecture 6: Eversheim, W.
Organisation in der Produktionstechnik Band 3: Arbeitsvorbereitung, VDI-Verlag, Düsseldorf, 1988
Wiendahl, H.-P.
Betriebsorganisation für Ingenieure Hanser Verlag, München, 1989
N.N.
Methodenlehre der Planung und Steuerung Teil 1: Grundlagen Teil 2: Planung Teil 3: Steuerung Hrsg.: REFA Verband für Arbeitsstudien und Betriebsorganisation e.V. Hanser Verlag, München, 1985
N.N.
Handbuch der Arbeitsvorbereitung Teil I: Arbeitsplanung Teil II: Arbeitssteuerung Beuth-Verlag GmbH, Berlin
Kief, H.B.
NC/CNC-Handbuch '93/94 NC-Handbuch-Verlag, Michaelstadt, Stockheim, 1993
N.N.
DIN 66025 Programmaufbau für numerisch gesteuerte Arbeitsmaschinen Hrsg.: Deutscher Normenausschuß, 1983
Pritschow, G. Spur, G. Weck, M.
Tendenzen in der NC-Steuerungstechnik Carl Hanser Verlag, München, Wien, 1993
Hackstein, R.
Produktionsplanung und -steuerung (PPS) Ein Handbuch für die Betriebspraxis VDI-Verlag, Düsseldorf, 1984
Spur, G. Stöferle, Th.
Handbuch der Fertigungstechnik, Band 6, Fabrikbetrieb, Carl Hanser Verlag, München, Wien, 1994
Eversheim, W.
Arbeitsplanung, Handbuch der modernen Fertigung und Montage Hrsg.: K. Brankamp, Verlag Moderne Industrie, München, 1975
Diels, A.
Systematischer Aufbau von Methodenbanken für die Arbeitsplanung dargestellt am Beispiel der Arbeitsplanerstellung und NC-Programmierung, Dissertation RWTH Aachen, 1989
Tönshoff, H.K. Hamelmann, S.
Strategische Ausrichtung der Arbeitsplanung CIM-Management 2/93
Process planning and operations scheduling
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Lecture 6
Literature Lecture 6: Eversheim, W. Schulz, J. Luszek, G.
Arbeitsplanerstellung für die Montage Industrieanzeiger 108 (1986) 20
Eversheim, W.
Integrierte Arbeitsplanung und Fertigungsfeinsteuerung Schneewind, J. ZwF 87 (1992) 7
Lange, U.
Wie produktiv ist die Arbeitsplanung? Produktivitätsverbesserung in der Arbeitsplanung eines Maschinenherstellers, CIM-Management 1/92
Eversheim, W.
Produktentstehung In: Eversheim, W.; Schuh, G. (Eds.): Betriebshütte Produktion und Management Springer-Verlag. Berlin, Heidelberg, New York, 1996
Eversheim, W.
Produktentstehung In: Eversheim, W.; Schuh, G. (Eds.): Betriebshütte Produktion und Management Springer-Verlag. Berlin, Heidelberg, New York, 1999
Eversheim, W.
Organisation in der Produktionstechnik Band 1: Grundlagen, VDI Verlag, Düsseldorf, 1996
Eversheim, W.
Organisation in der Produktionstechnik - Arbeitsvorbereitung Springer-Verlag, Berlin, 1997
Eversheim, W. Schneewind, J.
CAP-Einführung RKW-Verlag, Eschborn, 1993
N.N.
REFA - Methodenlehre der Planung und Steuerung Teil 3: Zeitermittlung, Erstellung von Arbeitsunterlagen, Werkstattsteuerung, Carl Hanser-Verlag, München, 1985
Wiendahl, H.-P.
Betriebsorganisation für Ingenieure Carl Hanser-Verlag, München, 1985
Hamelmann, S.
Rechnerunterstützte Arbeitsplanung - was gibt der Markt her? Die Arbeitsvorbereitung, Bd. 30 (1993)
Eversheim, W. Bochtler, W Humburger, R.
Die Arbeitsplanung im geänderten produktionstechnischen Umfeld, VDI-Z 137 Nr. 3 (1995), S. 88-91
Eversheim, W. Deuse, J.
Formation of Part Families based on Product Model Data Production Engineering Vol. IV/2 (1997), S. 97-100
Process planning and operations scheduling
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Lecture 6
Definitions and examples of functions in process planning and scheduling
Design What Process planning
Areas of production
How Operations scheduling
Whereby
Operations control
Manufacture
How much When
Assembly
... includes all one-off planning measures which ensure the manufacture-oriented production of a product, while taking economic efficiency into constant account. Examples: • Drawing up a parts list for manufacture • Materials planning • Operations sequences planning • Manufacturing resources planning
• Determining standard times • NC-programming • Cost planning • Methods and investments planning
... includes all measures required in the course of the order processing operations set out in the operations schedule. Examples:
Where
• Determining requirements for assemblies and single parts
Who
• Determining net requirements
• Materials disposition • Operating machine • Detailed deadline planning
• Operating dates for in-company • Harmonising capacity manufacture © WZL Figure 1
Notes on Figure 1: Process planning is divided into the areas of operations scheduling and operations control. In operations scheduling, decisions are made regarding WHAT and HOW manufacturing has to take place using WHICH (kind of) resources. In operations control, the issues are HOW MUCH WHEN WHERE and BY WHOM a work-piece or assembly is manufactured. In practice the term “operations scheduling” (“work scheduling”) is often replaced by ”production planning” or “process planning”. Likewise, the term “operations control” is sometimes replaced by “operations management”, “production control” or “process control”. Within operations scheduling there are differences between industry (serial production) and craft (individual production).
Process planning and operations scheduling
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Production management I (Prof. Schuh)
Lecture 6
Input and output documents of process planning Input documents
Output documents Planning documents/ tools
Design drawing machine file standard work schedules computing
Drawing of manufacturing resources NC-program Quality control plan
Arbeitsplan
Non-order specific additional documents Welle
Manufacturing parts list
Design parts list
Work schedule
Order data
Process planning
Completed with order data
Operations scheduling
Operations control
Order specific follow-up documents to work schedule (total/ partial deduction) Adjustment of capacity Work progress control Efficiency survey Use of material Compliance with deadlines
© WZL Figure 2
Notes on Figure 2: If manufacture has to be economically efficient, all information acquired in the course of process planning must be documented using suitable information media, i.e. production documents and instructions. The operations schedule is the basis for drawing up the order-specific production documents. Depending on how they will be used, the production documents contain the complete operations schedule (complete outlet) or an excerpt of the operations schedule`s heading data, containing the data of one process step each (partial outlet). To draw up the production documents, in addition to the input documents planning documents and tools are used that will be introduced later within this lecture. Today, production documents are usually generated by a PPS*-system (production planning and control; PPS: production planning system). *PPS is the connecting point in which production and order data, material administration, scheduling and capacity management meet and in which they are managed in master data records. The objective is to plan, control and supervise organisationally the process of production from drawing up an offer up to the dispatch of the complete product. In doing so, special emphasis is not given on technical but on quantity-, deadline- and capacity criteria. (Note: Further information about PPS-systems is given in PM I L7 and in PM II L3.)
Process planning and operations scheduling
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Production management I (Prof. Schuh)
Lecture 6
Operations schedule for the manufacture of a drive shaft Header Sheet:
Date: 07/19/2002 Order No. PM1V6B3 Engineer: W. Müller Area: Quantity: Designation: Drive shaft 1-20
Work Schedule
1
Un-machined shape and dimensions:
Material: Work cycle No.
10 20 30 40 50 60 70
Drawing No..: 170-0542
St 50
Round stock
Work cycle description
Cost center
Saw round stock to 345 mm length Cut round stock to 340 mm and centre Turn shaft completely Drill threaded holes and cut threads Mill feather key groove Grind bearing seats Finished part control
60 mm Wage group
Un-machined weight: 7.6 kg
Machine group
Manufacturing auxiliary resources
Finished weight: 4.6 kg
tr [min]
te [min]
30
10,0
30
2,0
30
2,6
20
5,2
300
04
4101
340
06
4201
360
08
4313
350
07
4407
400
09
4751
3104
45
4,7
510
07
4908
-
20
6,7
900
-
9002
-
10
3,8
1001 1051 1101/1121/ 1131 1201/1231/ 1233
Organisational data Task specific data
Work cycle specific data
© WZL Figure 3
Notes on Figure 3: The most important document for production and assembly apart from the drawing is the operations schedule (work schedule/ work sheet). The function of the operations schedule is to structure the manufacturing task and to specify the time required to complete each unit. For individual production such a time management is not necessary. The data in the work schedule are divided into three groups: - organisational data to label the operations plan clearly - task-oriented data which clearly label and characterise the initial and the final state of a part of assembly to which the operations schedule relates - work cycle related data which characterise the individual operations in detail, giving manufacturing equipment, standard times, additional texts etc. This description must not be too long but must contain all important data. IT-systems supporting operations scheduling are called CAP-systems (computer aided planning) as well as CAPP (computer aided process planning). Usually, computer aided operations scheduling aims not only at a reduced expense of planning but also at an improved planning quality. Whereas units for operations control (operations schedule management) within PPS-systems often offer only elementary functions of editing for the drawing up and the modification of work schedules, CAP-systems support individual planning functions more intensively.
Process planning and operations scheduling
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Production management I (Prof. Schuh)
Lecture 6
Functions of operations scheduling short term planning functions Process parts lists Draw up • assembly part lists • production part lists
Planning preparation • Consult design dept.
Draw up work schedules • production work schedule • assembly work schedule
NC-programming • Write parts programs -NC-machines -robots
Functions of operations scheduling
• Compile planning documents Cost planning • Preliminary costing • Feasibility study
Planning manufacturing resources • Developing production resources for special purpose machining tasks
Material planning •Planning: types of store and store locations •Logistic concepts
Quality assurance • Inspection planning • Quality planning
short-/ long-term planning functions
Investment planning
Methods planning
Planning
Developing
• manufacturing resources • facilities
• production methods • planning methods
long-term planning functions © WZL Figure 4
Notes on Figure 4: The functions of operations scheduling are classified as short- or long-term planning functions. Whereas the economic aspects of order processing are planned and specified in the manufacturing and assembly areas as short-term activities, the objective of long-term planning is to develop appropriate measures to ensure that the organisation and layout of these areas is economically efficient. Frequently it is distinguished between the tasks of process planning and management of production systems.
Process planning and operations scheduling
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Production management I (Prof. Schuh)
Lecture 6
Planning methods for drawing up operations schedules Repeat planning Basis: same or old work schedule available
Work schedule Part No. 4711
Modification of operational data Application in case of changes in production conditions or in work-pieces
Variants planning Basis: standard work schedule
Planning effort
Application useful only in the case of a limited number of part categories
Adjustments planning Basis: similar or old work schedule available Application to part families Selective access to work schedule required
Planning from scratch (new)
StandardWork schedule
Search criteria: - Drawing No. - Part designation - Classification No. Stock of work schedules
Planning experience
Basis: expert knowledge and availability of planning documents Not part-based Planning documents © WZL Figure 5
Notes on Figure 5: Depending on the reason for planning and the planning principle adopted, various planning methods can be used to draw up an operations schedule. Variants planning, adjustments (adaptation) planning and planning from scratch are methods used to draw up a completely new operations schedule. The modification of an operations schedule because of changes in the workpiece or in the conditions of production is called adjustments planning. When only the order-specific organisational data such as quantity and order number are altered, this is referred to as repeat planning. The objective is to reduce the planning from scratch (new planning) to minimum.
Process planning and operations scheduling
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Production management I (Prof. Schuh)
Lecture 6
Process sequence to draw up operations schedules Machining task Design drawing Quantity Specification of un-machined part Arbeitsplan
Type/ shape Dimensions Weight
Determination of work cycle sequence Arbeitsplan
Work cycles Sub-work cycles
Selection of production resources Arbeitsplan
Machines Jigs and fixtures Tools
Determining standard times Arbeitsplan
Set-up times Unit times
© WZL Figure 6
Notes on Figure 6: The individual planning steps involved in drawing up the work schedule are not always performed sequentially. The process is frequently iterative: • The definition of the initial part aims at fixing the un-machined shape and data considering technological (form, surface, material), economical (number of items, acquisition and machining costs) and timing (acquisition time) requests. The results are the kind of starting part (forging piece, flat steel, round stock), its geometry, weight etc. • The work cycle sequence, i.e. the order in which a material or a body is lead from raw into finished state by changing its shape and/ or its property of substances, constitutes the most important information about the manufacturing of a work-piece for all the divisions concerned. • For every operation within the work schedule the production means and devices (machines, facilities and tools) necessary for the execution have to be defined. The selection takes place considering technical variables (e.g. working room dimensions). The decision is made out of technically possible alternatives under consideration of economical criteria. • The definition of standard times contains the determination of the target times for each operation.
Process planning and operations scheduling
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Production management I (Prof. Schuh)
Lecture 6
Structure and calculation of standard times Conceptual meaning of standard times
Structure of standard times
Preparing operating resources e.g. procure tools, set up, take down Irregularly occurring times, e.g. machine starting times
Basic setting-up time trg
+ Setting-up additional time trv Setting-up recovery time trer
=
Supplement, depending on level and duration of load
+ + Non-productive time tn
Basic time tg
+
Time for people to recover
Calculate (guideline values for machining data), measuring, comparing
Additional time tv
+
Machine-specific tables
Recovery time ter
= Irregularly occurring times, e.g. preparation at beginning of shift
Supplement (approx. 5-15%) of setting-up time (allowance)
Setting-up time tr
Productive time th
Regular times, contributing only indirectly to work
Machine specific tables
+
Time for people to recover Time with direct progress in relation to production order
Approach to calculating standard times
Time per unit te Execution time ta = te * m
Supplement (approx. 5-15%) of basic time (allowance) Supplement, depending on level and duration of load
Order time T = tr + ta = tr + (te * m) m = quantity © WZL Figure 7
Notes on Figure 7: The standard times or target times of operations are determined in the standard time calculation phase. These data are very significant because important functions and decisions relating to: - date setting - capacity planning - costing - quotation costing - investment planning and - payment, e.g. piece-work or bonus payments are based on them. Methods to define standard times have variant degrees of accuracy. Usual methods are: - estimation (based on experience) - usage of planned current market values (tables) - recording times - calculation (e.g. formula for calculating productive time, cf. exercise) To determine the standard time of a partial work process it is possible to divide it into suboperations or stages. The definition of productive and non-productive time is made for each stage then. tv and ter are often given only as a safety factor to tg. The setting-up time can be even greater than te. Therefore it is indispensable for the calculation of order time. The calculation of order time is the basis for every operations scheduling.
Process planning and operations scheduling
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Production management I (Prof. Schuh)
Lecture 6
Computer Aided Planning (CAP)
Work cycle number
Date of process
Work cycle description
Tool group
© WZL Figure 8
Notes on Figure 8: CAP (computer aided planning) as well as CAPP (computer aided process planning) means the use of computers within production planning, e.g. for the creation of NC*-information, work plans and parts lists. The geometrical, numerical, technological and structural data resulting from design and construction are translated within operations scheduling into organisation and control data for production, assembly and quality assurance (production-, assembly- and control planning). The required production-, assembly- and control methods, operating resources and operation sequences as well as the resulting times and materials have to be defined individually. Sometimes even parts of cost- and investment planning are classed with work scheduling. The result of operations scheduling are work schedules and also NC, robot- and control programs, provided that completely or partly computer aided production-, assembly- and quality assurance processes follow. Computer aided planning aims at managing the mentioned tasks by using the aid of information technology. Furthermore, the data flow from design to operations scheduling and forward to the areas of production, assembly and quality assurance is to be optimised. *NC (numerical control) stands for the numerical control of machine tools. The route- and switch-information is binary-coded and input into the machine tool by saving media such as diskettes or CD-ROMs or it is input directly by transmission from a control computer (DNC: direct numerical control) or alternatively from an integrated computer that is freely programmable (CNC: computer numerical control).
Process planning and operations scheduling
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Production management I (Prof. Schuh)
Lecture 6
Basic components of CAP-systems neutral to business
Data input
dependent on business
Definition of work cycle progression Selection of machines
System progress control Current planning data
Standard processing Use of data
Data output
Planning master data
Definition of subwork cycle progression Selection of tools and mechanisms
definition of work cycle data
© WZL Figure 9
Notes on Figure 9: CAP-systems often represent special solutions or they have to be provided with company-specific master data before being applied. Therefore, many companies focus on proprietary development. Generally, CAP-system components can be divided into neutral and work-specific system modules. The modules independent from users contain innately existing possibilities for dialoguedesigning respectively for designing in- and output as well as mechanisms for data file handling, for planning process control and for the converting of standardand decision tables.
Process planning and operations scheduling
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Production management I (Prof. Schuh)
Lecture 6
Planning stages in the NC-process chain Process planning (overall planning) Planning of the production process
Work schedule Work cycle data Work cycle No. 20
Work cycle
Cost centre
NC-turning
47115
Operations planning (Detailed planning) Detailing of work cycles
Work cycle:
Operation plan NC-turning
SWC-No.
Sub-work-cycle
Tool
10
Facing
SCLR 2525
NC-programming PROGRAM % N001 G91 S200 M04 N002 T0103 M06
© WZL Figure 10
Notes on Figure 10: NC-programming can be regarded as the most detailed form of making operations schedules since all information required for the automated manufacturing operations must be available. The NC-program details the results of the operations planning, i.e. the description of the sub-operations or stages, down to the level of individual movement and switching commands.
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Production management I (Prof. Schuh)
Lecture 6
Organisational category
Programming methods
Methodical category
Methogical and organisational classification of NC-programming systems manual mechanical
Graphical-interactive programming systems
Computer programming systems
Shop-floorbased programming systems
Shop-floor programming systems (manual input)
Record-based programming conforming to DIN
Menu N010 N020 N030 N040 N050 N060 N070 N080 N090
Text editor
G17 G41 D2 G01 X125 X105 X090 G03 X075 G01 X075 X025 X045
Y050 F300 Y040 Y025 J15 Y020 Y060 Y060
Remote from machine
Remote from machine
Machine-oriented, linked to machine
© WZL Figure 11
Notes on Figure 11: There are various methods of programming that can be classified depending on the location they are used at and on the method they are based on. Whereas the remote-from-machine programming operations based on higher-level programming languages (e.g. APT (automatically programmed tools) -technique) are non-machine-dependent, the machine-oriented systems usually depend on the control system. Within NC-programming for simple work-pieces there is a trend towards shopfloor-oriented programming, since this ensures that the qualifications of the machine operators are utilised. Ideally, the data flow from engineering is continuously and without any disruption a digital one, i.e. without manual collection of data along the chain.
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Production management I (Prof. Schuh)
Lecture 6
General sequence of manual NC-programming Resources
Experience of planner
Planning steps
Outcomes
Specify machine sequence
Specify tools Tool file
Machine description
Standard value
Diagrams
amax = f (die plate, length of cutting edge, machine torque, max. cutting load)
Allocate place in magazine
Determine cutting data
Subdivide cutting operation
Calculate tool paths © WZL Figure 12
Notes on Figure 12: The technique of manual programming, in which each individual movement and switching operation conducted by the machine is determined and encoded by the NC-programmers themselves, is rarely used nowadays. Within NC-programming the definition of the coordinate systems of work-pieces, tools and machine tools as well as the dimensioning of drawings is essential. Pre-conditions and approach to define an NC-program are the knowledge of machine tools parameters (e.g. working area, revolutions per minute), knowledge of regulation and control (e.g. input format) and knowledge of machining possibilities (advance- and cutting velocity, infeed). Manual programming contains: 1. Combination of geometrical and technological tasks to a work plan according to the work steps and to a program sequence plan 2. Translation of the operational tasks given by a text into a short form according to certain rules (presentation of information according to DIN 66025 in short form). To each work step one sentence is dedicated: a group of words which are treated as an entity and which contain the complete data for the accomplishment of one work step. Sentences contain variant data/ information. 3. Transcription of these predefinitions (encoding). Encoding means allocating signs of one character set to the signs of another character set. Carriers of information can be punched tape, diskettes, magnetic tapes or rams. Basically, the planning steps involved in manual programming are also contained in automated programming operations. However, in these systems the planning steps are conducted in a computer-assisted or, in some cases, automated operation.
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Production management I (Prof. Schuh)
Lecture 6
NC-programming system
Simulation of tool routes and standard machine components
Tool selection
shaft
NC-programming List of parameters
© WZL Figure 13
Notes on Figure 13: Computer aided NC-programming of a machine tool contains the positioning of a machining program using a problem-oriented programming language including the subsequent converting in an IT-system (EDP-equipment) in order to gain the numerical control program (according to DIN 66025-1/2: Deutsches Institut für Normung e.V. (DIN); the German institute for standardisation). The formulation of the part program can take place interactively-graphically.
Process planning and operations scheduling
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Production management I (Prof. Schuh)
Lecture 6
Functions of operations control Process planning
Operations scheduling
Material planning
Operations control
Scheduling, capacity planning • Throughput scheduling
• Work distribution and provision
Deadline overview
Stock level
• Stock level control
Shop-floor control
Time
• Determination of requirements Consumption
Deadline
• Capacity planning
• Progress monitoring
Costs
Optimal order quantity
Load
Time
• Order planning
Xopt
Quantity
Time © WZL Figure 14
Notes on Figure 14: According to REFA (Reichsausschuss für Arbeitszeitermittlung; Association for Time and Motion Studies), the function of operations control is to give instructions for, to monitor and to ensure the execution of tasks in terms of quantity, date, quality and cost. This is based on the work and assembly schedules drawn up in the operations scheduling department and on the order dates. The objectives of the control system, some of which are contradictory, are: - to observe deadlines - to ensure short throughput times for the materials and low levels of capital commitment and - high use of capacities coupled with low operating equipment and human resource costs.
(Note: Materials management as part of the function of operations control is explained in PM I L4/5, management of deadlines and capacities in PM I L7).
Process planning and operations scheduling
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Production management I (Prof. Schuh)
Lecture 6
Multi-dilemma of operations control
Workload
Scheduled delivery date
Lead time
Transfer to capital lockup © WZL Figure 15
Notes on Figure 15: Two challenges must be taken into account within the multi-dilemma of operations control: • Conformity between workload in production (by customer orders respectively market specific orders) and own capital commitment • Adjustment of lead time of production orders with the scheduled delivery date. At this point, the wait time within the lead time and the delivery date should be considered.
Process planning and operations scheduling
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Production management I (Prof. Schuh)
Lecture 6
Order- and capacity-based scheduling Phase 1
Phase 2
(Focus: work-piece)
(Focus: machine)
Order-based scheduling
Capacity-based scheduling
Deadline plan
Deadline plan
Order 1
1.1, 1.2, 1.3
Order 1 Order 2 Order 3
1.1, 1.2, 1.3 2.2, 2.3 3.1, 3.2, 3.3
Deadline overview
Deadline overview Lead time for order 1
Work systems
A
B
Lead time for order 1
1.1
A
1.2
C
B
1.3
C Deadline
1.1
2.2
3.1
1.2
3.2
2.3
1.3
3.3
Deadline © WZL Figure 16
Notes on Figure 16: When setting the dates for customer-oriented production, the start and completion dates for each step (operation) must be determined with the completion date in mind. Various types and methods of date-setting are used. Within order-oriented scheduling, only the data relating to one order are taken into account. The basic scheduling methods (e.g. forward and back-ward scheduling (c.f. PM I L7) are used. Within capacity-oriented scheduling, the mutual dependency between orders and therefore between capacity limits is considered. As a rule, at first order-oriented then capacity-oriented scheduling is conducted.
Process planning and operations scheduling
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Production management I (Prof. Schuh)
Lecture 6
Load
Time- and machine-based harmonisation of capacity
Load
Technical capacity harmonisation
Time Time
Machine A
Machine A Machine B
Machine B
Machine C s e ion tiv pt na e o r te in Al ach m
n -e o iv t i a t op rn ine e t Al ach m
s
Combination of technical and time-based capacity harmonisation
Time
n -e o iv ti a t op rn ine e t Al ach m
s
Time-based capacity harmonisation
© WZL Figure 17
Notes on Figure 17: Within capacity planning, the distribution of activities among the individual units of capacity is optimised, under consideration of the load limitations. Capacity harmonisation and capacity adjustment are possible measures. A further distinction is made between technical (e.g. parallel dispatching of an order on another machine) and time-based capacity harmonisation (e.g. the same machine, but later dispatching). In industrial practice, time-based and technical capacity harmonisation operations are usually combined. Normally, the time-based harmonisation is first, in order to retain optimum use of capacity in terms of both engineering and cost. Placing an order with an external company (extended work-bench principle) is a further option.
Process planning and operations scheduling
L6 page 17
Production management I (Prof. Schuh)
Lecture 6
Capacity management (PPS-system) Start-up of production A Handling time
Control period
Transitional period
1. Cut within production
occupied
2. Cut within production
free
Start-up of production B Control period
Capacity of machine 1
1. Cut within production
Transitional period
1.1.Produktions cut within schnitt für production Auftrag for order B Occupied Belegung with durch order AA Auftrag
Handling time
2. Cut within production
Frei Free Frei Free
2.2.Produktion cut withinschnitt für production Auftrag for orderBB
1. Day
2. Day
Occupied Belegung withdurch order C Auftrag C (Split factor 0) (Spittfaktor0)
3. Day © WZL Figure 18
Notes on Figure 18: Handling time/ Transitional period/ Control period Handling and control time mark constant values. Handling time is added before the start-up of a process operation, control time is added after the ending of an operation. Both factors do not occupy any capacity but they heighten the machining time. The transitional period indicates a time exposure that arises from product transport within manufacturing from one workplace to an other or from an effort conditional on production after a process operation (e.g. cooling, drying etc.). Split factor (cut within production) If the temporal effort of production for one process operation cannot take place on a single work day because of lack of capacity or duration of the production, time has to be spread on one or several days. If such a splitting is not possible or only in parts because of production reasons, the splitting can be managed by depositing the split factor within the process operation. Capacity factor Usually, the basic capacity of a workplace is deposited within the machine group with 100% of the available time. This available capacity can be used and scheduled only lessened because of external factors such as machine's cooling times and values from practical experience. Therewith, additional capacity reserves for squeeze situations can be created.
Process planning and operations scheduling
L6 page 18
Production management I (Prof. Schuh)
Lecture 6
Measures for adapting to capacity Internal/ external alternative capacity
Overtime/ short-time working
Additional shift
Investment
Internal influencing factors
External influencing factors
• effectiveness • duration • internal priority
• external priority • penalty • labour market • economic situation
Selection and execution of measures geared to adapting to capacity © WZL Figure 19
Notes on Figure 19: When the company-specific parameters change, e.g. expansion, acquisition of a new major customer etc., the capacity harmonisation measures are generally not enough and it becomes necessary to adapt capacity to the changed parameters.
Process planning and operations scheduling
L6 page 19
Production management I (Prof. Schuh)
Lecture 6
Monitoring the execution of tasks Production planning
Production planning
Shop-floor control
Target
Target-Actual comparison
Actual - Schedule card - Pay slip
Work papers
PDA
Production Feedback of quantities and schedules Provision PDA: Production data acquisition
Starting/ completion data
Quantity of goods Material consumption © WZL Figure 20
Notes on Figure 20: According to REFA, monitoring involves recording the actual data and any deviations of the actual data from the target data continuously or at regular intervals throughout the performance of the task. In addition to data collection during manufacture (recording operating data), i.e. monitoring in the narrower sense, quality, cost and working conditions must be monitored, i.e. monitoring in a broader sense. The planning precision in operations management depends largely on the up-todateness of the actual data available.
Process planning and operations scheduling
L6 page 20
Production management I (Prof. Schuh)
Lecture 6
Increase in planning complexity by the use of new manufacturing concepts
flexible production system manufacturing cell
Planning depth
planning of transport and monitoring
shop-floor programming
+
Simulation of manufacturing and production processes tool monitoring work-piece transport pallet store and pallet changer automatic measuring
NC-programming
+ conventional
Planning effort
Automation
planning of operation sequences
programming handling devices partial operating cycles detailed geometry tool selection cutting values operation standard times
• increase in planning tasks with higher levels of automation • increase in planning for complete machining © WZL Figure 21
Notes on Figure 21: The depth of planning required and with it the planning outlay rises as the level of automation increases. Process and operations planning must therefore be rationalised by systematisation and, in some cases, automation.
Process planning and operations scheduling
L6 page 21
Production management I (Prof. Schuh)
Lecture 6
Options for rationalisation in process planning Options for rationalisation Systematisation
Automation working sheet – part list admin.
Organisation Product-oriented structure Order processing centre
Documents Catalogues of materials Catalogues of standard times
Planning methods/ tools Planning on the basis of - planning results - planning rules
Requirements • little outlay for processing and administration • high quality planning and continuity • transparent planning procedures • short throughput times • gradual introduction and expansion
materials disposition drawing up of work schedules
materials planning
ITSystems
capacity planning
NCprogramming order scheduling
monitor progress
Target for rationalisation Fields of activity of process planning
Company parameters • sector • range of products • manufacturing structure • type of manufacture • manufacturing technology • organisational structure • staff training © WZL Figure 22
Notes on Figure 22: Concrete objectives are a requirement for successful rationalisation. Automation depends on systematisation.
Process planning and operations scheduling
L6 page 22
Production management I (Prof. Schuh)
Lecture 6
Application of various planning methods Planning effort
Repeat planning
Variants planning
Adjustments planning
Planning from scratch (new)
fill in
adjust
draw up
Basis
Alternative planning methods
KR- 47 11
copy 4711
shaft 4711 D > xx L < yy
4712 4710 4709
same or old work schedules
D < xy L > yx
4711 Mill groove
D > xx L < yy D > xx shaft L < yy D < xy D > xx L > yx L
yx D < xy L > yx
standard work schedules
+ similar or old work schedules
catalogues, tables,.. © WZL Figure 23
Notes on Figure 23: Distinctions in terms of short-term planning outlay can be drawn between methods of operations scheduling. Similarities between products are used as a source of information (cf. figure 5). The main concern should be with a preferably high systematisation. It facilitates an unerring retrieval. Within repeat planning, the appropriate operations schedule is seeked from the existing work schedules by using a classifying drawing number; it is completed and the organisational order data are updated. Because of the minor planning effort it should be checked for every new order to what extend the required planning documents can be made available by using repeat planning. Variants planning is based on the use of standard work schedules. After enhancement and adjustment of the work schedule data given in the standard operations schedule (e.g. necessary because of changed parts parameters) and after a completion with the order-specific details the new originated work schedule is filed under a new identity number. In adjustments planning (similarity planning) one also reverts to existing operations schedules, completes the organisational order data and accomplishes modifications, e.g. of work process data. This method is applied mainly with modifications of parts geometry or with using new and more economic procedures. Existing partial solutions to new work schedules are combined or existing work schedules for similar parts are adapted. For an efficient similarity planning a well directed access to drawings of similar parts and to the work schedule inventory has to be possible. Auxiliary means enabling fast access are keys for classification and strips for object parameters. With the launch of new products with which planning adjustments are no longer economic it is necessary to plan from scratch (new planning).
Process planning and operations scheduling
L6 page 23
Production management I (Prof. Schuh)
Lecture 6
Methods for the rationalisation of operations scheduling
Requirements • accuracy • up-to-dateness • reproducibility • ... • level of automation • type of manufacture • proportion of skilled workers • lot size • ...
Data transfer • organisational data • feedstock data • operations • sub-operations • machine groups • cost centres • set-up times • times per unit •cutting data •additional text • ...
MANUFACTURE
WORKPIECE ANALYSIS • project structure • frequency scale (standard parts, similar parts, product group parts)
Main focuses of rationalisation
OPERATIONS SCHEDULING
ANALYSIS OF ACTION incorporating • type of action • duration of action • planning methods • planning means
ANALYSIS OF INFORMATION • document-bound communication • non-document-bound communication © WZL Figure 24
Notes on Figure 24: The required depth of planning can be ascertained from the analysis of the company parameters. The rationalisation objectives can be derived from this depth of planning. The main focuses of rationalisation can be detected from an analysis of operations scheduling. Methods for this analysis of operations scheduling are the analysis of action, analysis of information and the work-piece analysis. By using work-piece analysis parts can be grouped according to similarity criteria (compare work-piece describing classification systems, e.g. Opitz-Key). Similar parts provide an area of application for standard work papers. In contrast to the work-piece analysis, the ABC-analysis classifies the range of parts according to quantifiable criteria, e.g. depending on the costs incurred. The potentials of rationalisation within operations scheduling can be identified on the basis of an analysis of action (activity analysis).
Process planning and operations scheduling
L6 page 24
Production management I (Prof. Schuh)
Lecture 6
Factors impacting on the system used to draw up operations schedules Organisation
Range of parts/ machining methods
Information flow
frequency
Volume of project data
number
new working sheets modified working sheets
1997
CAP/CAPPSystem
- planning from scratch - variants planning - similarity planning - repeat planning
Software
Hardware
2002
Planning aids
nomograms
Planning methods
tables catalogues
files
- operating system - applications software - communications software - firmware - ... © WZL Figure 25
Notes on Figure 25: The presented tools and methods are the main selection criteria for a CAP- as well as for a CAPP-system to automate operations scheduling.
Process planning and operations scheduling
L6 page 25
Vorlesung 6
Produktionsmanagement I (Prof. Schuh)
Produktionsmanagement I - Anhang 6 -
Arbeitsvorbereitung / Arbeitsplanung
Vorlesungsbetreuer: M. Phornprapha, M. Eng. [email protected] WZL, R. 504 Tel.: 0241-80-27383
© WZL
Arbeitsvorbereitung / Arbeitsplanung
A6 Seite I
Produktionsmanagement I (Prof. Schuh)
Vorlesung 6
Ausgangsteilbestimmung Auftragsdaten Werkstückdaten Werkstoffdaten
Ausgangsteilbestimmung
Schmiedeteil
Bestimmung der Rohform
Halbzeug Auftragsstückzahl: < 3000
Auftragsstückzahl: > 3000
Stückzahl: 2
Ausgangsmaterial: Stange rund
Ermittlung der Rohteildaten
345
Materialkatalog 60
Werkstoff: ST 50 Material: Stange rund, blank Durchmesser[mm] Länge[mm]
• Material: Stange rund, blank • Durchmesser: Ø = 60 mm • Länge: L = 340 + 5
L = 345 mm
• Gewicht: G = 2,21 * 345/100
G = 7,6 Kg
Gewicht[Kg/100mm]
40 50
2000 2000
0,97 1,53
60 70
2000 2000
2,21 3,00 © WZL Bild 1
Anmerkungen zum Bild: Die Ausgangsteilbestimmung dient zur Festlegung von Rohform und Rohteildaten unter Berücksichtigung der Anforderungen des Werkstücks anhand folgender Kriterien: • technologische (Gestalt, Oberfläche, Werkstoff), • wirtschaftliche (Stückzahl, Beschaffungs- und Bearbeitungskosten), • zeitliche (Beschaffungszeit). Die Ergebnisse dieser Planungsfunktion sind: • Art/ Form des Ausgangsteils (z.B. Schmiedeteil, Flachstahl, Rundmaterial), • Geometrie (z.B. Durchmesser, Länge, Höhe), • Gewicht, •...
Arbeitsvorbereitung / Arbeitsplanung
A6 Seite 1
Produktionsmanagement I (Prof. Schuh)
Vorlesung 6
Arbeitsvorgangsfolgeermittlung • Auftragsdaten • Rohteildaten • verfügbare Fertigungsverfahren • Werkstückdaten
Arbeitsvorgangsfolgebestimmung Fertigungsablauf
Erläuterung
AVO 10: Sägen
Säge: Ausgangsmaterial: Stange rund, mit Aufmaß zum Planen
AVO 20: Ablängen und Zentrieren
Zentriermaschine: Vorbedingung für:
AVO 30: Komplett Drehen
Drehmaschine: Vorbedingung für:
-Drehen -Bohren
-Gewinde schneiden
-Fräsen
-Schleifen
AVO 40: Bohren und Gewindeschneiden
Bohrmaschine: 2 Axialbohrungren M6 x 20 für die Befestigung eines Deckels
AVO 50: Fräsen
Fräsmaschine: Nuten fräsen für Paßfeder mit Paarung P9
AVO 60: Schleifen
Schleifmaschine: Lagersitz auf Nennmaß schleifen
© WZL Bild 2
Anmerkungen zum Bild: Die Arbeitsvorgangsfolge, d. h. die Reihenfolge, durch die ein Stoff oder Körper über schrittweise Verändern der Form und/ oder der Stoffeigenschaften vom Rohzustand in einen Fertigzustand überführt wird, stellt für alle betroffenen Unternehmensbereiche die wichtigste Information zur Herstellung eines Werkstücks dar.
Arbeitsvorbereitung / Arbeitsplanung
A6 Seite 2
Produktionsmanagement I (Prof. Schuh)
Vorlesung 6
Fertigungsmittelbestimmung • Auftragsdaten • Rohteildaten • verfügbare Fertigungsverfahren • Werkstückdaten
Fertigungsmittelbestimmung für Arbeitsvorgang "Komplett Drehen"
Maschinenauswahl
KopierDaten des M SpitzenM NCM Beispiels 1 drehmaschine 2 drehmaschine 3 drehmaschine Kostenstelle/ Lohngruppe
-
360/08
360/08
360/07
max. Durchmesser [mm]
60
340
300
350
max. Länge [mm]
340
700
700
650
Prozess- M1 kosten
M2
M3
M2
M3
M1
Auftragsstückzahl
2 1 2
50
Werkzeugauswahl
150
100 Stückzahl
Kostenstelle:360
Lohngruppe :08
Werkzeugkatalog Operation WerkzeugNr. Längs1101 schruppen
Bezeichnung
Skizze
Inv.-Nr.
Schruppdrehmeißel Längs-HM
1101
Schruppdrehmeißel Plan-HM
1102
© WZL Bild 3
Anmerkungen zum Bild: Zu jedem Arbeitsvorgang im Arbeitsplan müssen die zur Ausführung erforderlichen Fertigungsmittel/ -hilfsmittel (Maschinen, Vorrichtungen und Werkzeuge) bestimmt werden. Die Auswahl erfolgt dabei zuerst unter Berücksichtigung technischer Einflussgrößen (z.B. Arbeitsraumabmessungen, Maschinengenauigkeit). Die Entscheidung zwischen technisch möglichen Alternativen wird dann unter Berücksichtigung wirtschaftlicher Kriterien vorgenommen. Dazu werden in der Regel nur die variablen Kosten berücksichtigt, die jedoch auch losfixe Kostenanteile (z.B. zur NC-Programmerstellung) beinhalten können.
Arbeitsvorbereitung / Arbeitsplanung
A6 Seite 3
Produktionsmanagement I (Prof. Schuh)
Vorlesung 6
Vorgabezeitbestimmung • Auftragsdaten • Rohteildaten • verfügbare Fertigungsverfahren • Werkstückdaten
Vorgabezeitbestimmung für den Arbeitsvorgang „Komplett Drehen“ Lfd. Nr. 1
Arbeitsschritte
th (min)
Einspannen
1. Einspannung
tn (min) 0,30
2 3
Reitstock positionieren rechte Seite komplett Drehen
1,08
0,15 1,60
4 5
Umspannen Stufe Drehen
0,05
0,40 0,30
6 7
Werkzeugwechsel Fase rechts Drehen
0,03
0,30 0,15
8 9
Werkzeugwechsel Einstechdrehen
0,06
0,30 0,25
10
Ausspannen Gesamt
1,22
0,15 3,90
Grundzeit Verteilzeit (Zv = 12%)
5,12 0,61
Erholzeit (Zer = 8%) Stückzeit (te)
0,41 6,14
2. Einspannung
X
= Arbeitsschritt
Arbeitsschritt 3 umfasst Längsdrehen, Fase Drehen, Freistiche Drehen Rüstzeit: tr = 4,6 min (Tabellenwert) © WZL Bild 4
Anmerkungen zum Bild: Die Methoden zur Bestimmung der Vorgabezeiten haben einen unterschiedlichen Genauigkeitsgrad. Gängige Verfahren sind: • Schätzen (Erfahrungswerte), • Verwenden von Planzeitwerten (Tabellen), • Zeitaufnahme, • Berechnen. Die Haupt- und Nebenzeiten werden entweder pro Arbeitsvorgang bestimmt, oder es erfolgt eine Feinplanung des Arbeitsvorgangs mithilfe von Teilarbeitsvorgängen (Arbeitsschritten), wobei die Zeiten dann pro Teilarbeitsvorgang ermittelt werden. Die Stückzeit für den Arbeitsvorgang ergibt sich aus der Summe von Haupt- und Nebenzeiten der Teilarbeitsvorgänge unter Berücksichtigung von Zuschlägen für die Verteil- und Erholzeit.
Arbeitsvorbereitung / Arbeitsplanung
A6 Seite 4
Produktionsmanagement I (Prof. Schuh)
Vorlesung 6
Vorgabezeitberechnung eines Teilarbeitsvorgangs Vorgabezeitberechnung „Stufe-Drehen“ Lfd. Arbeitsschritte Nr. 1
Anstellen
2
Stufendrehen (Längsdrehen)
3 4
th
0,10 0,05
Zurückfahren
0,10
Messen
0,10
Gesamt
0,05
Hauptzeitberechnung (th): (Formeln siehe Hauptzeittabelle) th = π*D*L*i f*vc*1000
tn
i = D-d 2*ap
D = 60; d = 45; L = 30 (Maße aus der Zeichnung) ap = 7,5; f = 0,6; vc = 180
th ≈ 0,05 min
Nebenzeittabelle (Kst. 360) Drehoperation
Anstellen
Längs
Plan
0,10
0,12
tn (min) Rücklauf mm
Zurückfahren Messen
50
100
150
200
tn (min)
1,10
0,11
0,12
0,13
Messlänge mm
50
100
150
200
tn (min)
0,10
0,11
0,12
0,13
0,30
Schnittwerttabelle Schruppen Werkstoff: St50 Schneidstoff: P25 LängsPlandrehen drehen ap (mm) 8,0 6,0
{
f (mm)
0,6
0,5
vc (m/min)
180
160 © WZL Bild 5
Anmerkungen zum Bild: Für die Vorgabezeitermittlung eines Teilarbeitsvorgangs ist eine Aufgliederung des Teilarbeitsvorgangs in Arbeitsstufen möglich. Die Haupt- und Nebenzeitermittlung erfolgt dann pro Arbeitsstufe. In dem Beispiel wird die Ermittlung der Hauptzeit mithilfe einer Hauptzeitformel (vgl. Übung) gezeigt, wobei die technologischen Daten einer Schnittwerttabelle entnommen werden. Zur Bestimmung der Nebenzeitanteile wird hier eine Nebenzeittabelle genutzt.
Arbeitsvorbereitung / Arbeitsplanung
A6 Seite 5
Produktionsmanagement I (Prof. Schuh)
Vorlesung 6
Systematik der Standardarbeitsplanerstellung und -nutzung
Bildung von Werkstückgruppen ähnlicher Teile metrisches Gewinde
Standardarbeitsplanerstellung
WhitworthGewinde metrisches Feingewinde
Standardisierung der Werkstückgruppen
WZL-Arbeitsplanung 1 2 3 4 5 6 7 8
Arbeitsvorgangsstruktur
Planungsregeln
Maschinendaten Werkzeugdaten Vorgabezeiten
Dokumentation der Planungsinformationen
Nutzung
Zeichnung
Standardarbeitsplan
Anpassung/ Erweiterung
Aktueller Arbeitsplan © WZL Bild 6
Anmerkungen zum Bild: Für eine Teilefamilie (Werkstückgruppe) werden Standardarbeitsabläufe ermittelt, die in Standardarbeitsplänen dokumentiert werden. Der Arbeitsplaner ordnet das Werkstück einer Teilefamilie zu und kann dann den zugehörigen Standardarbeitsplan nutzen. Der Arbeitsplan für das Werkstück entsteht durch die Kombination der erforderlichen Wahlarbeitsgänge des Standardarbeitsplans.
Arbeitsvorbereitung / Arbeitsplanung
A6 Seite 6
Produktionsmanagement I (Prof. Schuh)
Vorlesung 6
Informationsgrundlagen und Inhalt eines NC-Programms Werkstück X
Geometrie Technologie
P7
Startpunkt
Werkstücknullpunkt
X
Z
K
Maschinendaten
P5 Z
Kreismittelpunkt- Vorschubabstand befehl I
z
P1
P6
Satz WegNr. bedingung Wegbefehle G
x P4
P3
P2
NC-Programmblatt
N
Maschine
Bearbeitungssegment
Drehzahlbefehl
F
S
Werkzeugbefehl
Hilfsfunktionen
T
M
T0103
M06
% N01
G95
N03
G00
N04
G01
M04
S 350
N02 150
300 Maschinendaten
Wohin wird gefahren ?
N05 G01 Wie wird gefahren ? 6000
Bewegungsdaten
Schnittwerte
Technologische Daten © WZL Bild 7
Anmerkungen zum Bild: Als Eingangsinformationen für die Erstellung des NC-Programms müssen neben den Werkstückdaten (Geometrie- und Technologiedaten) auch Angaben zu der einzusetzenden Bearbeitungsmaschine vorliegen. Das Ergebnis der (manuellen) Programmierung ist ein Teileprogramm im Satzformat gemäß DIN 66 025, das die explizite Vorgabe aller Bewegungen, Funktionen und Werte für die Durchführung der Bearbeitung enthält.
Arbeitsvorbereitung / Arbeitsplanung
A6 Seite 7
Produktionsmanagement I (Prof. Schuh)
Vorlesung 6
Arbeitsplanung in Abhängigkeit von der Fertigungsart
ARBEITSPLANUNG
ANFORDERUNGEN
Genauigkeit Aktualität Reproduzierbarkeit
Automatisierungsgrad Fertigungsart Anteil Facharbeiter Losgröße …
Einzel- und Kleinserienfertigung
Serienfertigung
DATENÜBERGABE Organisatorische Daten Rohmaterialdaten Arbeitsvorgänge Teil-Arbeitsvorgänge Maschinengruppen Kostenstellen Restzeiten
1 Stück 1h
Auftragsstückzahl Planungsaufwand AVO
Nr.
MGR
05
1147 ABSAEG 5
05
1213 t = 5,1; t = 2,1 R e
10
2010
FRAES
9
10
2017 FREAS
15
3020
S - BO
5
20
4015 SCHLEIF 3
te
Nr. MGR
Zeiten je Einheit
Schnittwerte Zusatztexte … % 20 10
FERTIGUNG
80 Stück 6h
-10 -20
Art der Arbeit ABSAEG
t e = 8,06; t R = 2,1 s = 140 mm/min v = 80 m/min
15
durchschnittliche Abweichung der ermittelten von der gemessenen Vorgabezeit
+20% -
+5 -5
+5% © WZL Bild 8
Anmerkungen zum Bild: Aus der Analyse der betrieblichen Randbedingungen kann die notwendige Planungstiefe ermittelt werden. Aus ihr können die Rationalisierungsziele abgeleitet werden.
Arbeitsvorbereitung / Arbeitsplanung
A6 Seite 8
Produktionsmanagement I (Prof. Schuh)
Vorlesung 6
Anzahl der verschiedenen Einzelteile
Aufbau der Teilevielfalt in einer Werkzeugmaschine
300 250 200 150 100 50 0 Teileart
Normteile
Ähnlichkeitsteile
Produktspezifische Teile
Schrauben
Deckel Zahnräder Gehäuse
Betten
Stifte Passfedern
Buchsen Wellen Lagerböcke Hebel
Schlitten
© WZL Bild 9
Anmerkungen zum Bild: Durch die Werkstückanalyse können Teile nach Ähnlichkeitskriterien gruppiert werden (vgl. werkstückbeschreibende Klassifizierungssysteme, z.B. Opitz-Schlüssel). Ähnlichkeitsteile bieten eine Einsatzmöglichkeit für Standardarbeitspläne. Im Unterschied zur Werkstückanalyse ordnet die ABC-Analyse das Teilespektrum nach quantifizierbaren Kriterien, z.B. nach den verursachten Kosten.
Arbeitsvorbereitung / Arbeitsplanung
A6 Seite 9
Produktionsmanagement I (Prof. Schuh)
Vorlesung 6
Zeitaufwand für Tätigkeiten bei der Arbeitsplanerstellung Tätigkeiten
Zeitaufwand
- Auftrag prüfen auf Vollständigkeit - Material vorhanden
4
- Zeichnung lesen - Rücksprache Konstruktion
5
- Fertigungstechnische Kontrolle - Rücksprache Werkstatt
5 3
- Ähnlichkeitsteile suchen - Arbeitsvorgangsfolgeermittlung - wirtschaftlicher Verfahrensvergleich
30
- Prüfung/ Korrektur der Arbeitsvorgangsfolge
5 15
- Zeitkalkulation - Auftrag abschließen - Weitergabe des Arbeitsplans zur Datenerfassung
3
- Datenerfassung
3 2
- Endprüfung 0
3
6
Basis: Erfassungszeit 2 Wochen, 80 Arbeitspläne, 5-8 Arbeitsvorgänge/ Plan
9
12
15
Zeit
30 min © WZL Bild 10
Anmerkungen zum Bild: Mit der Tätigkeitsanalyse werden Rationalisierungspotentiale in der Arbeitsplanung aufgedeckt.
Arbeitsvorbereitung / Arbeitsplanung
A6 Seite 10
Produktionsmanagement I (Prof. Schuh)
Vorlesung 6
Anwendung von Planungshilfsmitteln in der Arbeitsplanung
Lohnkostentabelle
Tabelle mit Maschinenstundensätzen
Zeitrichtwertkatalog
Schnittwerttabelle
Werkzeugkatalog
Vorrichtungs-, Messmittel-, Lehrenkat.
Maschinenkatalog, Maschinenkartei
Materialprospekt des Handels
Materiallagerkatalog
Relativkostenkatalog
Standardarbeitspläne
ähnliche Arbeitspläne
Wiederholteilkatalog
Anwendungsbereich
Normen, Vorschriften, Richtlinien
Planungshilfsmittel
Stücklistenverarbeitung
Arbeitsplanerstellung
Ausgangsteilbestimmung Arbeitsvorgangsfolgebestimmung Maschinenauswahl Vorrichtungsauswahl Werkzeugauswahl Vorgabezeitberechnung NC-Programmierung Sonderbetriebsmittelplanung © WZL Bild 11
Anmerkungen zum Bild: Die Tabelle ordnet die Hilfsmittel der Arbeitsplanung den Tätigkeiten zu, die sie unterstützen. Mit einem Relativkosten-Katalog können beispielsweise alternative Verfahren für eine kostenoptimale Bearbeitung ausgewählt werden. Die Maschinenkarte liefert dem Arbeitsplaner Informationen zur Auswahl und zum Einsatz von Maschinen. In Richtwerttabellen werden in Abhängigkeit von Werkstoff/ Schneidstoffpaarungen technologische Einstellbedingungen festgehalten, die nach verschiedenen Zielkriterien wie maximale Standzeit oder minimale Kosten ausgerichtet sind.
Arbeitsvorbereitung / Arbeitsplanung
A6 Seite 11
Produktionsmanagement I (Prof. Schuh)
Vorlesung 6
Relativkosten für verschiedene Schweißverfahren
Werkstoff: St 5 Relativkosten
a
4 3
MIG/MAG-Schweißen Metall-Lichtbogenschweißen
2
Unterpulverschweißen 1
3
4
5
6
7
Schweißnahtdicke a
8
9
10 Legende: MIG: MAG:
Metall-Intergas-Schweißen Metall-Aktivgas-Schweißen
nach: Busch © WZL Bild 12
Anmerkungen zum Bild: Mit einem Relativkosten-Katalog können alternative Verfahren für eine kostenoptimale Bearbeitung ausgewählt werden.
Arbeitsvorbereitung / Arbeitsplanung
A6 Seite 12
Produktionsmanagement I (Prof. Schuh)
Vorlesung 6
Dokumentation von Maschinendaten
© WZL Bild 13
Anmerkungen zum Bild: Die Maschinenkarte (z.B. AWF-Karte) liefert dem Arbeitsplaner Informationen zur Auswahl und zum Einsatz von Maschinen.
Arbeitsvorbereitung / Arbeitsplanung
A6 Seite 13
Produktionsmanagement I (Prof. Schuh)
Vorlesung 6
AACHEN
INFOS-Richtwerttabellen für das Drehen Richtwertempfehlung für das Außenlängsdrehen Wärmebehandlung geglüht auf BG
Werkstoffnummer 1.7335
Zugfestigkeit 500 N/mm2
Härte 148 HB
Oberfläche vorgedreht
kc1,1=144
VSTAND=571
E=-0,20
F=-0,10
Schnittgeschwindigkeit α=5°
γ=6°
Schneidteil
Werkstoff 13CrMo 4 4 1-mc=0,86
G=-0,20
H=0,24
vcmax=350m/min
vcmin=200
λ=0°
χ=70°
Vorschub f (mm)
Beschichtetes Hartmetall Besonderheiten Mehrbereichssorte
Schnitttiefe ap (mm) 1.0
2.0
3.0
4.0
5.0
.250
350 50 3 87
330 110 6 165
320 170 9 240
310 220 12 310
300 280 14 375
.315
340 60 4 107
310 130 7 195
300 200 10 283
290 270 13 365
290 340 17 456
320 80 5 128
300 170 9 240
290 250 12 348
280 340 16 448
270 420 19 540
.400
Plattenform SPUN 120308
I N F O S
Schnittgeschw. Vc (m/min)
P M K
Anwendungsbereich 01 10 15 20 25 30 35 40
Schnittkraft Fc (daN) Schnittleistg. P (kW) Volumenrate (cm3/min) Standzeit T = 10 min VBmax = 0,3 mm nach:
EXAPT © WZL Bild 14
Anmerkungen zum Bild: In Richtwerttabellen werden in Abhängigkeit von Werkstoff/ Schneidstoffpaarungen technologische Einstellbedingungen festgehalten, die nach verschiedenen Zielkriterien wie: - maximale Standzeit oder - minimale Kosten ausgerichtet sind.
Arbeitsvorbereitung / Arbeitsplanung
A6 Seite 14
Produktionsmanagement I (Prof. Schuh)
Vorlesung 6
Anwendungsmöglichkeiten von Zugriffssystemen auf Planungshilfsmittel
Lohnkostentabelle
Tabelle mit Maschinenstundensätzen
Zeitrichtwertkatalog
Schnittwerttabelle
Werkzeugkatalog
Vorrichtungs-, Messmittel-, Lehrenkat.
Maschinenkatalog, Maschinenkartei
Materialprospekt des Handels
Materiallagerkatalog
Relativkostenkatalog
Standardarbeitspläne
ähnliche Arbeitspläne
Wiederholteilkatalog
Normen, Vorschriften, Richtlinien
Planungshilfsmittel
Klassifizierung Suchsysteme
Identnummer (Suchsystem)
Alphabetisches Inhaltsverzeichnis
Werkstückorientierte Klassifizierung Verfahrensorientierte Klassifizierung Kreuzliste
Nummer Indextabelle Sachmerkmalleiste © WZL Bild 15
Anmerkungen zum Bild: Die Vielzahl der Dokumente und Hilfsmittel ist nur durch einen systematischen Zugriff zu nutzen. Die unterschiedlichen Planungshilfsmittel können mit den aufgeführten Zugriffssystemen verwaltet werden.
Arbeitsvorbereitung / Arbeitsplanung
A6 Seite 15
Produktionsmanagement I (Prof. Schuh)
Vorlesung 6
Dokumentation der Auswahlkriterien in Entscheidungstabellen
1801
Härten ENTSCHEIDUNGSTABELLE
Auswahlkriterien Drehen
Arbeitsvorgangsnummer
Auswahlkriterien
1901
Nuten ziehen
2002
Auswahlkriterien 2101
Auswahlkriterien
NC-Bohren
Auswahlkriterien
Dokumentation in Entscheidungstabellen
Schleifen
Auswahlkriterien
Maßnahmen
2201
Nuten fräsen
Bedingungen
2001
2002
lfd.
REGELN
Nr.
R1
R2
Nut vorhanden
1
X
X
Nutbreite<=10
2
X
F.-Gewicht<=10
3
X
Rohdurchm.>20
4
X
Werkstoff C45
5
X
Rohlänge>=250
6
AV 802 vorhanden
7
NIMM AV 2002
1
X
GEHE NACH AV 2101
2
X
GEHE NACH AV 2402
3
R3
X X X X
© WZL Bild 16
Anmerkungen zum Bild: In IT-Systemen zur Arbeitsplanerstellung (CAP: Computer Aided Planning) ist die Planungslogik häufig in Form von Entscheidungstabellen implementiert.
Arbeitsvorbereitung / Arbeitsplanung
A6 Seite 16
