Process planning and operations scheduling

Transcrição

Production management I (Prof. Schuh)
Lecture 6
Production Management I
- Lecture 6 -
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
L6 page I
Lecture 6
Structure of lecture No. 6:
1. Overview of the process planning department
L6 page 1
1.1 Definition of process planning and delimitation of
operations scheduling from operations control
L6 page 1
1.2 Information media of process planning
L6 page 2
2. Operations Scheduling
L6 page 3
2.1 Functions of operations scheduling
L6 page 4
2.2 Drawing up operations schedules
L6 page 5
2.3 NC-programming
L6 page 10
3. Operations control
L6 page 14
3.1 Functions of operations control
L6 page 14
3.2 Scheduling and capacity planning
L6 page 16
3.3 Shop floor control
L6 page 20
4. Manufacturing concepts and rationalisation within process planning
L6 page 21
4.1 Planning complexity and new manufacturing concepts
L6 page 21
4.2 Options for rationalisation in process planning
L6 page 22
4.3 Methods for the rationalisation of operations scheduling
L6 page 24
5. Factors impacting on the system used to draw up operations schedules
L6 page 25
6. Appendix
6.1 Supplement
L6 page 1
7. Exercise
7.1 Calculation exercise
E6 page 1
7.2 Self-Calculation exercise
E6 page 1
L6 page II
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.
L6 page III
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
L6 page IV
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
L6 page V
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).
L6 page 1
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.)
L6 page 2
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.
L6 page 3
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.
L6 page 4
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.
L6 page 5
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.
L6 page 6
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.
L6 page 7
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).
L6 page 8
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.
L6 page 9
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.
L6 page 10
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.
L6 page 11
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.
L6 page 12
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.
L6 page 13
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).
L6 page 14
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.
L6 page 15
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.
L6 page 16
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.
L6 page 17
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.
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 <D
yy< xy
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
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
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
• 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
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
• 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
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
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
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
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
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
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
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
Arbeitsvorgangsfolgebestimmung
Maschinenauswahl
Vorrichtungsauswahl
Werkzeugauswahl
Vorgabezeitberechnung
NC-Programmierung
Sonderbetriebsmittelplanung
© WZL
Bild 11
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
Mit einem Relativkosten-Katalog können alternative Verfahren für eine kostenoptimale
Bearbeitung ausgewählt werden.
A6 Seite 12
Vorlesung 6
Dokumentation von Maschinendaten
© WZL
Bild 13
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
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
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
In IT-Systemen zur Arbeitsplanerstellung (CAP: Computer Aided Planning) ist die
Planungslogik häufig in Form von Entscheidungstabellen implementiert.
A6 Seite 16