1. A PRESENTATION ON WEB BASED MANUFACTURING
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2. INTRODUCTION With the advent of the World Wide Web (www),
information distributed at different location can be accessed and
shared by users anywhere in the world using Web tools such as
Web-browsers. The Web technologies have been applied widely in
developing manufacturing systems such as marketing, design, process
planning, production, customer service etc. distributed at
different locations into an integrated environment.
3. WHY WEB BASED MANUFACTURING? 1. Capturing global audience
The users of a manufacturing system can be in any part of the world
and therefore it is vital that the system should be widely
acceptable. The web based manufacturing instead of developing
customized client - server architecture depends on well defined and
seasoned client-server architecture running on the internet, which
is the www, to serve application logic in the form of Java applets,
which provide platform independent means of accessing the
system
4. 2. HANDLING DATA LOSS AND OUT OF ORDER DELIVERY OF DATA:
When the web has been chosen as platform for development of the
system, it should be noted that the application layer of web, HTTP
runs over the transport layer protocol, TCP which provides reliable
(connection-oriented) in order byte stream data transfer takes care
of the problem associated with data loss and out of order delivery
of data. 3. COORDINATING MULTI-USER ACCESS The nature of operation
of some operation in mfg. system such as drilling is such that only
one client should have full control over the drilling machine at
any given time. Due to this restriction, coordination of multi-user
access is vital in ensuring fairness of use and safe operation of
the machining unit.
5. 4. REDUCED SUSCEPTIBILITY TO TEMPORAL COMMUNICATION DELAYS:
An important consequence of deciding against real time direct
control of the machining unit is that susceptibility of the
proposed systems performance is reduced, thus addressing the
uncertain time delay problem
6. FRAMEWORK OF WEB BASED MANUFACTURING
7. WBM FRAMEWORK (CONTD.) Web pages embedded with JAVA applets
provide an interface for the operations. Using the web interface,
the authorized remote clients (first tier) provide machining
parameters which are relayed to the web server. The machining
parameters upon reaching the server (middle tier) constitute a
part-program which is stored in a job file scheduled for execution
of machining process The machining operation is monitored by the
network camera, which is a part of the middle tier providing real
time feedback to the remote user.
8. WBM FRAMEWORK (CONTD.) In addressing security issues
pertaining to the web based manufacturing system, the firewall is
the first line of defense in restricting unauthorized access to the
server and therefore the drilling machine In addition to this, the
web server authenticates users prior to granting permission to
submit jobs, monitor the machining process or participate in
virtual discussion Finally all the sensitive communication between
the client and the server is carried over TLS (Transport Layer
Security) thereby ensuring confidentiality, data integrity and
server authentication
9. MODULAR ARCHITECTURE OF THE WEB BASED MANUFACTURING
SYSTEM
10. JOB SUBMISSION The process of job submission requires
coordinated interaction between the client and the server. On the
client side is a JAVA applets responsible for reading and
validating input machining parameters prior to encoding and sending
it over to the server The web server receives the machining
parameters posted via CGI, sets up necessary environment variables
and executes the CGI script responsible for storing machining
parameters in a job file, adding the job file to the scheduling
system and then notifying the machine controller about the presence
of the job file in the queue. Finally the user is informed about
the status of the job submission by means of a job ID uniquely
identifying their job.
11. JOB SCHEDULING SYSTEM For the web based manufacturing
system to get acceptance from users who are likely to be situated
in different time zones, fairness in scheduling of jobs has been
given the prime consideration. According to the first come first
serve (FCFS), a non preemptive scheduling algorithm has been chosen
for the scheduling system which also has provisions for
administrative users to set priorities in managing urgent jobs
12. JOB STORAGE SYSTEM The storage structure for processing the
jobs consists of four directories under a common parent directory.
The logic behind such structure is that while the user interface
transmits machining parameters and the CGI script stores it in the
job files, there is a possibility that the user can terminate the
transmission by simply closing the browser. In such cases it is
pointless to execute partially complete job.
13. JOB STORAGE (CONTD.) The machining parameters written to
the buffer directory and only when the job file is complete, it is
moved to the job directory The job directory stores all the job
successfully received by the server and waiting execution. The
scheduler picks up the next job in queue from the job directory and
places it in the execution directory. The machine controller
executes job from the execution directory and after the completion
the job file is moved to the completed directory which can be later
used for billing the client
14. JOB EXECUTION Under the normal scenario, job execution
commences once the job file has been placed in the jobs directory
and the job submission systems sends notification about the job
file to the machine controller The main program which coordinates
interaction between the objects in executing a job is the job
server which runs as background process registered as a system
service. Just like any other system service, the job server daemon
is easily controllable using the standard operating system
utilities such as chkconfig and sevice.
15. JOB MANAGEMENT SYSTEM After a job has been submitted it may
have to wait in the job queue for some time before its turn come up
for execution. In the meanwhile the user submitted the job needs
some way of knowing the position of their job in the queue and also
whether their job has been completed. Furthermore, there has to be
provision that allows users to delete their own job from the queue
if they wish to cancel the job
16. JOB STATUS The carefully designed job storage structure of
the scheduling system seamlessly allows the remote users to check
the status of their job at various stages of processing In similar
fashion, a sorted directory listing of the completed directory
enables the users to check if their job has been processed Likewise
listing the job file execution directory indicates the job that is
currently being executed.
17. REMOTE PROCESS MONITORING AND ONLINE COLLABORATION In an
effort to lessen the impact of geographical separation between the
remote user and the manufacturing equipment, the web based
manufacturing has provisions for remote process monitoring and
virtual discussion between remote designers.
18. A Methodology For Web based Manufacturing Management and
Control
19. INTRODUCTION For the implementation of the methodology,
tele- manufacturing is used, which a part of the electronic-
manufacturing concept . The customer uses the manufacturing
services via web (Service Oriented Application - SOA) to execute
the operations and the necessary processes, designing and
manufacturing the desired part efficiently, using computational
tools for the development of the product life cycle.
20. OVERVIEW A. ERP Systems Generally, in each company, some
computer systems were developed to meet specific requirements of
the diverse business units, factories, departments and offices.
Thus, information was fragmented among different systems. The main
problems of this fragmentation are the difficulty in getting the
consolidated information, and the inconsistency of stored redundant
data in more than one system. ERP systems solve these problems by
including, in just one integrated system, functionalities that
support the activities of different companies .
21. B. Web Machining Methodology The Web Machining methodology
has the purpose of allowing the integration of the collaborative
design activities (CAD), process planning (CAPP) and manufacturing
(CAM). The procedure begins in the collaborative modeling of a part
using features in a context of remote manufacturing via web, in a
client- server computer model.
22. C. Cyber Cut Cyber Cut is a web-based
design-to-manufacturing system developed by Brown and Wright who
point out that, by providing access to the CAD interface over the
Internet, any engineer becomes a potential user of this on-line
rapid prototyping tool. A remote user would be able to download a
CAD file in some specified universal exchange format to the Cyber
Cut server, which would in turn execute the necessary process
planning and generate the appropriate NC code for milling.
23. THE PROMME METHODOLOGY PROMME is a methodology to enable
manufacturing and control management in a distributed manufacturing
environment. It is applied on the WebMachining virtual company,
whose shop floor is formed by three distributed manufacturing
systems. An ERP software was developed in order to carry out
manufacturing management, enabling the receipt of customer orders,
management functions, CAD/CAPP/CAM integration, and part
manufacture in one of the three manufacturing systems.
24. PROMME METHODOLOGY Consists of A. Distributed Shop Floor B.
ERP Manufacturing 1) Institutional module 2) Commercial module 3)
Integration with the Part Development Environment 4) CAP Computer
Aided Production i. Decision Making ii. Production Scheduling 5)
Integration with the Management Units of the distributed shop
floors
25. THE WEB-BASED SHOP FLOOR CONTROLLER (WSFC) FOR THE FMC AT
GRACO/UNB A web-based shop floor controller for the Flexible
Manufacturing Cell (FMC) at Graco/Unb (in Brasilia) was also
implemented, and it uses WWW resources to perform the remote
manufacture of parts. The FMC receives instructions from the
controller and converts them into the operations necessary to
manufacture the parts.
26. The web based shop floor controller (WSFC) should meet the
following requirements:- (a) it should support production Planning
(b) it should have functions to verify the availability of the
production resources allowing the instruction loading on the
workstations (c) it should control and monitor the production
process reacting on any abnormal conditions that can hinder the
fulfillment of the activities established previously on the
production planning.
27. A. COMMUNICATION WITHIN THE FMC In order to describe the
implementation of the control for the FMC at Graco/UnB, it is
important to visualize the FMC communication structure, describing
the method used by the operator to access the FMC resources B.
WEB-BASED SHOP FLOOR CONTROLLER The implementation architecture of
the controller should encompass the main functionality that the
real system should offer. The implementation architecture was built
based on object oriented technology.
28. 1) Implementation architecture Component diagram The
component diagrams of the Unified Modeling Language (UML) were used
to design and to document the implementation architecture. The GUIs
and the upper level functionalities are available on the client
module, while the lower level functionalities (e.g. direct
connection with the workstations) are available on the server
module. 2) Implementation under the distributed architecture To
provide remote access to the workstations (via web), maintaining
the portability that the system should offer, the web-based shop
floor controller was implemented in a clientserver
architecture.
29. C. RESULTS 1) Inspection and production planning The
inspection plan is included in the information used to plan,
control and monitor the inspection of the parts. This plan is
composed by a set of inspection programs previously recorded in the
database. Each program has the part geometry information (diameter
and tolerance of each feature that will be inspected), as well as
the inspection conditions (unit system, reference, scale, etc). The
Master Production Scheduling (MPS) is added to the work orders
recorded on the database. One work order has attributes such as
priority, due date, process time, etc., which will be used by other
WSFC modules.
30. 2) Scheduling production and dispatching After concluding
the production plan, the next step consists of establishing the
sequence in which the work orders will be manufactured. The
scheduling method adopted in this work is based on priority rules.
The WSFC communicates with each workstation in order to verify
whether it is available to receive a task upload. While the WSFC is
checking the workstation status, a report (log) of the executed
command is shown on right side of the GUI.
31. 3) Production monitor and quality control The GUI Quality
Control provides the human interaction with the quality control
process. The statistical method selected to control the process is
the pre-control, and this method is composed of three steps: to
qualify the process, operation, and sample frequency. The
inspection of a part starts with the positioning of the
manufactured part on the micrometer read unit. After positioning
the part on the micrometer and the programmed inspection
time(DataOutputTimer) expires, the micrometer sends the inspection
result to the WFSC via the RS232 interface.
32. CONCLUSIONS The proposed PROMME methodology contains a
concept for web-based manufacturing management that encompasses a
web based system, an ERP software written in the Java language, and
the presence of distributed manufacturing systems located in
different places. The web-based shop floor controller is a computer
system that uses Internet resources to promote the remote
manufacturing of parts. Besides of the portability and the remote
access via Internet, the WSFC schedules, controls and monitors the
activities on the shop floor. The implementation based on Java
technology enables the WSFC to be executed over the Internet
without the need for the user to install the application.
33. 1. Alberto J. lvares, Jos L.N. de Souza Jr., Evandro L.S.
Teixeira, Joo C.E. Ferreira , A Methodology For Web-Based
Manufacturing Management and Control . 4th IEEE Conference on
Automation Science and Engineering Key Bridge Marriott, Washington
DC, USA August 23-26, 2008 2. S. P. LAL , G.C. Onwubolu, Three
tiered web-based manufacturing system. , Department of Mathematics
and Computing Science, University of the South Pacific, Suva, Fiji
Islands, bDepartment of Engineering, University of the South
Pacific, Suva, Fiji Islands REFERENCES