Process planning and operations scheduling - WZL

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


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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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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.


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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


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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


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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).


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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.)


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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.


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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.


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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.


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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.


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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.


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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).


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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.


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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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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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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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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.


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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).


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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.


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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.


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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.


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Lecture 6

Capacity management (PPS-system) Start-up of production A Handling time

Control period

Transitional period

1. Cut within production

occupied


free

Start-up of production B Control period

Capacity of machine 1


Transitional period

1.1.Produktions cut within schnitt für production Auftrag for order B Occupied Belegung with durch order AA Auftrag

Handling time


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.


L6 page 18


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.


L6 page 19


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.


L6 page 20


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.


L6 page 21


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.


L6 page 22


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).


L6 page 23


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).


L6 page 24


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.


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


A6 Seite I


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, •...


A6 Seite 1


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.


A6 Seite 2


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.


A6 Seite 3


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.


A6 Seite 4


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.


A6 Seite 5


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.


A6 Seite 6


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.


A6 Seite 7


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.


A6 Seite 8


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.


A6 Seite 9


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.


A6 Seite 10


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.


A6 Seite 11


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.


A6 Seite 12


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.


A6 Seite 13


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.


A6 Seite 14


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.


A6 Seite 15


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.


A6 Seite 16

Process planning and operations scheduling - WZL

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