Figure 1: Workflows for
Control of Production Engineering
Sergey Larin, Alexey
Karpushin and Petr Sosnin
Sergey
Nikolaevich Larin, head of the complex production-engineering department of
Federal Research-and-Production Center ‘Research-and-Production Association
‘Mars’. [e-mail: larinmars@rambler.ru].
Alexey Nikolaevich
Karpushin, graduated from the Faculty of
Information systems and Technologies of Ulyanovsk State Technical University.
[e-mail: a.karpushin@ulstu.ru].
Petr Ivanovich Sosnin,
graduated from the Faculty of Radio-Engineering of Ulyanovsk Polytechnic Institute.
[e-mail: sosnin@ulstu.ru].
Abstract
The article presents and describes a set of tools for aspect-oriented
design of workflows in design and production engineering of pilot production.
An important advantage of the developed set of tools is a computer-aided
process for the development of design documents, tasks and interchange of data
(directive, reference and report documents) among design,
production-engineering services and cell-type systems. By now, the developed
system of pseudo-code programming tools for interface prototypes is a
time-proved system which has confirmed its stable operability in the mode of
real-production process.
Key words:
PSEUDO-CODE PROGRAMMING, INTERFACE PROTOTYPE, DYNAMIC COMPILATION.
The specific feature of pilot
instrument-making production whose products are to be embedded into
computer-aided systems (CAS), is a simultaneous work with several products
being at different life-cycle stages: design, engineering, prototyping,
technology development, creation of pilot sample, pilot lot or even small lot
[1]. Besides, the simultaneous work is usually supplemented by the necessity of
the account of instrument-making products (IMPs) used in CAS-type systems which
form product lines with extending range and constantly improving components.
The mentioned feature of pilot
production points out to the necessity to coordinate the IMP and CAS life cycles
according to the ISO/IEC 12207 standard. This coordination should include
parallel spiral interconnecting of design and engineering solutions resulting
in the creation of IMPs.
It is easy to agree that under the mentioned
conditions the value of IMPs for CAS depends, to a substantial extent, on how useful
the combination of design and engineering solutions and actions will be for pilot
production of IMPs. It should be noticed that controlled and effective combination
of design and engineering constituents in production-engineering of pilot
instrument-making production represents a problem which has not been solved by
now.
The article proposes a set of tools
for representation and mixing of design and engineering actions whose creation
and use are based on aspect-oriented design of workflow systems using the
software suite TechWIQA created by the authors on basis of the question-and-answer
modeling environment WIQA [2]. A task tree and question-and-answer models created
in this environment, enable to model workflows in different versions of their operational
mixing. At that, reasonable solutions are searched for using libraries for
typical design and engineering works.
The development purpose is to implement the set
of tools ensuring intellectual actions of a group of production engineers, into
design process [3]. The set ensures question-and-answer access to experience,
including its creation, modeling, systematization, transformation, storage,
accumulation and use.
A
methodology of object-oriented analysis and design was used during the work. As
a result, an engineering version of the methodology, based on a special kind of
reasoning (question-and-answer one) in a group of production engineers at the
stage of engineering-document design, was developed. Such system of tools is
for constructive service of reasoning of production-engineer group for a
certain project. The production-engineering control is one of the constituents
of the service.
A
set of works for design and engineering preproduction should
represent a coherent set of design and engineering business-processes, at that
each of them has a specified functional purpose and place in the set. However the
real practice shows that preproduction organization is not coordinated with
this requirement. The existing preproduction order is built not taking into
account reasonable design and engineering interconnections and particular
organizational and technical conditions for a specified type of production.
The problem is that, when making operational
engineering decisions and specifying engineering actions, it is necessary to take
into account not only cost estimating of design solutions but also other
values, and in the context of the specifications of the CAS under development.
The same is right for operational design solutions and actions.
The design and engineering constituents
of the common work should contribute to a common agreed solution. It is reasonable
to consider the combination of sets of design and engineering works from the point
of view of workflows [4] which are effectively mixed. It should be noticed that
workflow (in its most general meaning) is understood as a computer-aided business-processes
(full or partial, as a rule, within an
organizational structure describing functional roles and relations)
where documents, information, tasks are transferred in order to perform required
actions, from one participant to another according to a set of procedure rules.
Let's proceed
to details concerning the interconnections of the preproduction design and engineering
constituents. Traditional methods of preproduction design and engineering do not
enable to co-ordinate such very important links of preproduction as support of
adaptability to manufacture of product designs, design and engineering analysis
of product, development of labor standards, objective operational and
production, technical and economic planning, definition of a range of required techniques.
The tasks of
engineering-process design are
multi-variant. They include selection of equipment, cutting tools, techniques, calculation
of cutting methods etc. The engineering process under development has a considerable number of possible combinations of
transitions, charts, processing methods and operation combinations even for
simple parts.
Different
variants of manufacture processes of the same products in consequence of the structure
differences have different outputs: performance, prime cost, metal consumption,
equipment utilization etc. The availability of several variants for task solution
(engineering-process variants) results evidently in the task of the selection
of the best variant. In this case the best one is an engineering-process variant
ensuring the fulfillment of all the design-document requirements under
particular production conditions and returning the best output values. At that,
it should be noticed that the present-day stage of engineering-process development
automation is featured by the creation of complex systems including design, process
engineering and manufacturing of instrument-making products.
A generalized scheme of design
and engineering preproduction is shown in Figure 1 to demonstrate tasks to be
solved jointly within a specified organizational structure using standard and
reference data.
An engineering process as a
design object can be represented in form of a hierarchical structure divided into
several interconnected levels. As a result of such decomposition the process of
engineering-process design is reduced to the solution of tasks of different
levels of detail at the interconnected levels: from creation of composition and
structure of manufacturing route to development of control programs and
calculation of cutting modes to process some surfaces.
According to
the authors’ strong opinion, in automation of design and engineering
preproduction processes, thus in development of software for support of design
and engineering preproduction, it is reasonable to connect creation and solution
of a system of hierarchical tasks, and workflows of design and engineering
preproduction.
For
the computer-aided support of design and engineering preproduction processes on
basis of experience in workflow control, the authors developed a specialized
version of question-and-answer modeling environment for the development and
control of production engineering processes. The potential of the environment
is sufficient to support both engineering and design workflows. However from
the point of view of the content of support facilities the design part is
considered only from the positions of mixing of design and engineering tasks.
It should be noticed again that the
version proposed by the authors, enables the support of the development of single
engineering processes, repair of products and their components.
As a base, we used and adapted
a question-and-answer environment of CAS conceptual design NetWIQA. The result
of the adaptation, named TechWIQA, consists of the following components:
I. back end: 1. infobase;
2. library to work with
database;
3. application server;
4. client library;
II. front end:
1. configurator;
2. user’s WS;
3. plug-in to control staff
organizational structure;
4. plug-in to plan on basis of
Gantt charts.
Figure 1: Workflows for
Control of Production Engineering
The two components of the
system front-end were additionally developed:
1)
a plug-in to
control product structure, which ensures user interface to entry and edit hierarchy
of structure elements of a product under development, as well as support of required
references corresponding to different classifiers used in development of engineering
processes;
2)
a plug-in to
develop engineering processes, which ensures user interface to entry and edit
engineering-process operations, data of engineering norm-fixing, as well as the
creation of document sets for single engineering processes.
During the adaption, in the infobase structure 14
tables were left. They are required for storage of main data of the
question-answering environment, sufficient to solve given tasks. The tables are
following: projects (Projects), question-and-answer protocol (QAReg), types of QA-protocol
units (QATypes), status of QA-protocol units (QAStatus), reasons for status of QA-protocol
units (Reason), staff list (ManningTable), workers who are users of the question-and-answer
environment (Users), working groups (Groups), user joining working groups (GU),
tree of organizational structure (TreeNode), functional links of elements of
organizational structure (FuncLinks), task assignment to users (UT), task
assignment to working groups (GT),
planned terms for task fullfilment (PlanDates).
According to this, only
functions required for the work with data of the above tables were left in
other back ends.
We decided to use the question-and-answer
protocol for storage of reference data, product structure, engineering
processes and documents on them. In comparison with the addition of special
working tables for such data, this decision enabled to reduce the time for the
development of the system back-end, and the most important thing is that it
enabled to use mechanisms of data entry and editing, search and filtration,
access control, support of update history implemented for the question-and-answer
protocol. Besides, the decision enables to extend easily attributes of used
data, to implement developed components into workstations with different installed
versions of the question-and-answer environment due to the fact that the back-end
components are not required to be changed and the data transfer is not required
to be simplified.
The use of the question-and-answer
protocol for data storage assumes a computer-aided addition of task hierarchies
into it, questions and answers on basis of question-and-answer templates. We
included the following six files of these templates into the back-end in the
current version of the system:
1.
question-and-answer
templates for directories (file Directory.ini), containing the directory names
and types (hierarchical or list), as well as questions to display the directory
attributes. If the use of new directories is required, this file can be easily
added. That enables to increase the number of used classifiers without programmers’
help;
2.
a
question-and-answer template for product structure (file Structure.ini),
including questions to display attributes of product elements and lists of
possible values of some attributes. The hierarchy of the product-structure
elements is based on the hierarchy of QA-protocol tasks;
3.
a template
of tasks to be solved while creating and controlling engineering processes
(Tasks.ini file), including, e.g., ‘Generation of Documents on an Engineering
Process’, ‘Norm-Fixing for Engineering-Process Operations’ etc., as well as list
of required documents;
4.
a question-and-answer
template for structure of engineering process (file TechProc.ini), including
questions to display the attributes of engineering-process operations, used
equipment and man-hours in these operations, availability of parts, assembly
units and materials used for engineering process;
5.
a question-and-answer
template for methods sheet (MK.ini), including questions answers to which are
required to generate method sheets by all the types of forms according to a
selected type of engineering-process description;
6.
a question-and-answer
template for engineering instruction (TI1.ini), including standard content of engineering
instruction, e.g., on thermal processing of polymers, as well as questions answers
to which are required to generate such instructions for a particular engineering
process.
We included functionalities
for the work with data of the above templates into the application server and
client library. In the final version of the system, the template set will be extended
due to the inclusion of question-and-answer templates of all other kinds of
documents created during the development of single engineering processes according
to the GOST 3.1119-83 standard [5].
During the update of the
plug-in for the control of the staff organizational-structure a function to set
plan terms of the beginning and end of works and assign tasks to users and
working groups was implemented.
The
specific character of functionality and use principles of the additionally
developed component will be presented by fragments using basic interface
solutions of the TechWIQA tools.
Figure 2 shows a form of the
component ‘Control of Product Structure» for the work with data of classifiers
used during the work with engineering processes. In the given window you can browse
the directory content, work with its elements (element group), set values for
attributes, as well as import the content from other projects using similar classifiers.
Figure 2: Interface for Work with Directories
Figure 3 shows an
interface to control product structures, implying the entry of product-structure
elements taking into account their hierarchy, setting of their attribute
values, registration of tasks for the work with engineering processes for elements
being manufactured, selection of a description type of engineering processes as
well as setting of list of documents on them.
Figure 3: Interface for Control of
Product Structure
Figure 4 shows an interface
for the component «Engineering Processes» regarding the work with operations of
engineering processes under development. While working with the given
component, the employees responsible for the development of engineering
processes, add or edit their operations, specifying the key parameters:
designations of a shop, section and workstation where an operation is performed,
operation number and name, mechanization degree, lists of used equipment and
documents.
The operation content and
lists of used tools and jigs (production accessories) are also indicated within
a selected route description of an engineering process. The data on the product
completing with parts, assembly units or materials are also specified within a
selected route and operation or operation description.
For convenience, there is a
function to import engineering processes and their separate operations from
other structural elements of products or other projects.
In the window ‘Technical Norm-Fixing», the
employees responsible for this part of the work, enter pre-calculated data of parameters
for technical norms for each of the registered operations.
The window ‘Documents’ ensures
an interface to form a set of documents on an engineering process under a preliminary
selected list. First, the new documents are generated by templates or imported
from other engineering processes, then the data are downloaded from the server,
the document parameters are filled in and saved. After that, the documents can
be generated according to GOST standards in the Microsoft Word format, at that the
data of engineering-process operations and technical norm-fixing are borrowed
and do not demand re-entry.
Figure 4: Interface to Set
Operations of Engineering Processes
The current version of the system
ensures the support of the generation of methods sheets for engineering
processes for all the kinds of description as per the GOST 3.1118-82 standard [6] as well as engineering instructions as per the GOST 3.1105-84 standard [7].
The computer-aided
system of question-and-answer conceptual design of engineering documents and control
of production-engineering processes during manufacture of instrument-making
products increases considerably the efficiency of production-engineering
management at an enterprise due to the following:
¾
acceleration
of technological projects and, therefore, the whole production process;
¾
efficient
use of labor and information resources for engineering works in design production;
¾
improvement
of quality of engineering solutions in whole for instrument-making production;
¾
reduction of
costs for development of engineering documents (methods sheets, part lists).
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