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RFID at Work

Improve shop floor visibility with connected business and plant systems
  • Hesham El Deeb
  • Salwa Nassar
  • Adel Ghannam
September/October 2015

Pinpointing the location of products and components throughout a facility in real time is crucial for shop floor managers and their employees. Radio frequency identification (RFID) technology and effective enterprise resources planning (ERP) can significantly improve production control by making it possible to easily read valuable information stored on item tags. By coupling business and plant systems, authorized users gain visibility into order status and operational plans, decision cycle times are reduced, plant productivity increases, and the need for certain types of human intervention can be eliminated. The ultimate result is significant bottom-line improvement.

Many businesses still perform ERP tasks manually using paper documents including dispatch lists, work orders, and maintenance orders. Daily ERP outputs at such firms lack the essential, up-to-date information that should be considered and applied to business functions along with sales orders and marketing forecasts. Moreover, shop floor managers have a very limited view of the current work in process (WIP).

The ability to develop a prototype that can manage real-time interaction with back-end ERP systems presents a significant opportunity for improvement. Such a tool would effectively link ERP with shop floor activities in order to create an internet-based connection that can enable users located around the globe to inquire about the status of any order at any time. True shop floor visibility is a substantial competitive advantage—and it is particularly essential for companies that make or engineer to order.

For the purposes of this article, the practice described will be termed “e-manufacturing” because the technique connects an ERP system to a shop floor control solution via the internet. The information that follows was derived from a project funded by the Ministry of Scientific Research, Egypt, through the Electronics Research Institute. The objective of the project is to fulfill the immediate technological needs of Egyptian industry and the Egyptian economy.

Currently, this goal is being addressed via an e-manufacturing project at Mobica, a manufacturer of office and medical furniture, interiors, exteriors, building solutions, automotive supplies, and more. Company leaders aimed to integrate their ERP system with the valuable feedback coming from the shop floor using RFID technology. The end product is a fully working system on the factory floor of this Giza-based manufacturer. Established in 1976 with one factory in Egypt’s Abu Rawash industrial zone, Mobica’s industrial base now has expanded to include 15 factories and employ 2,400 people.

Using the e-manufacturing solution, these staff members can check the status of any customer order in real time, and the ERP planning engine can run without waiting for manual feedback from the shop floor. This is helping to eliminate conflicting manufacturing orders and clarify actual capacity. Shop floor operators also are now spending all of their time on real production work, rather than filling out forms and manually entering data into the ERP system.

Is it right for your operation? 

RFID and e-manufacturing are tools that monitor pre-specified objects. When deciding whether to use such an RFID-based solution, it is beneficial to first answer the following questions:

  • How can having more accurate and timely information improve business processes?
  • What is the optimum distribution potential for the specific factory?
  • What are the target objects that should be tracked?
  • What kind of tags would best suit the business needs in terms of read-write distance, frequency spectrum, interference sources, and conductivity of fixing surfaces?
  • What is the level of monitored granularity—piece level, which may be useful in discrete manufacturing, or material batch level?
  • What types of RFID tags, readers, and antennas on the shop floor will enable real-time data reading and writing?
  • What is the location accuracy required for each item being tracked?
  • Are there any serious risks involved with eliminating the manual (human) intervention?

Based on the answers to these questions, the decision can be made whether or not to continue with an e-manufacturing initiative. If a company decides to move forward, executives should keep in mind that the implementation process likely will include

  • technology exploration and requirements specifications
  • product design
  • product development and implementation, which include determining the equipment specifications, ordering according to national rules, installing the development environment, training the staff, tuning product designs, and internally testing the system
  • product testing and validation of equipment delivery, installation, live pilot, launch, and go-live.

The technical structure

The basic element of any RFID system is its data point. This is the location where the RFID tag is read. Using e-manufacturing, WIP can be monitored through a build ticket tag that moves along the routing path, starting from the input gate of material, as defined in the dispatch list imported from the ERP system via web services. Using the WIP tag, it is possible to track progress across all processes and stations through readers at each work center.

When developing such a system, the first step is to identify the key issues and goals involved with RFID tracking technology. Next, a set of design principles should be defined. It’s important to address and plan for the logical and technical structure requirements as well as the technology-related constraints and implementation stages. Finally, the prototype can be implemented, observed, and evaluated.

In the e-manufacturing system, each build tag contains fields including

• the customer sales order (or the internal order, in the case of make to stock)

• the output product identification number

• the route identification number, which identifies the sequence of operations at work centers.

Routing is important to make the system viable for job-shop manufacturing because there may be parallel routes for the product. The limited memory of low-cost tags (512 bits) requires that the data that is produced while moving the tag from one station to the next—such as in detailed routing—can be obtained interactively from the dispatch list on the shop floor control server.

E-manufacturing systems also involve each work center on the shop floor being monitored by a set of data readers and one or more antennas. The readers are mounted 5 meters above the shop floor and can read any RFID tag in the input-buffer area of the monitored work center, which is a circle on the floor with a radius of 3.6 meters.

The data points are equipped with a touchscreen monitor displaying the WIP tags that are waiting in the input-buffer area. At the shop floor exit, a tag bearing the product identification number is attached to the output product in preparation for finished or semi-finished inventory and customer delivery. The tag is read at the output gate, and the information is transferred to the central ERP system.

An RFID system requires the many layers to work together in order to make the tracking of goods more efficient. (See Figure 1.) The bottom layer is the physical RFID network that contains RFID tags, antennas, readers, touchscreens, and the shop floor communication network. The second layer is the network control middleware, which is responsible for

• producing the tags’ identification numbers

• reading and writing the tags

• managing the data transfer between the data point and the reader

• managing the transfer between the reader’s network and the associated antennas to the shop floor control system

• managing any radio frequency technology problems on the shop floor.


Practical advice

To implement a successful RFID and e-manufacturing solution, consider the following guidelines:

  • Think about using long-range (up to 5 meters), passive RFID tags to accommodate the physical size of moving objects. These tags are low cost and allow a read-write scope of the previously mentioned 3.6-meter-radius circle.
  • Look for modern tags that meet the Electronic Product Code Class 1, Generation 2 standard and that operate at ultra-high frequencies.
  • Be selective in what information is chosen to be stored in the tags in order to take advantage of lower-cost options that have 512 bits of memory. For example, a build-ticket tag that contains only the sales order (or internal make-to-stock order), product identification number, and build-ticket tag identification number may be advisable. Any other data, such as routing information, may be obtained from the daily dispatch list stored in the shop floor database.

 

  • Use the international low-level-reader protocol to simplify the development of standard application program interfaces according to the requirements of each particular project.
  • Base software on the Eclipse Integrated Development Environment for Java. Eclipse is an extensible, open-source development platform and set of services for building applications from plug-in components.
  • Use a shop floor control system that does not add any required high-cost user licenses to the back-end ERP system.

Finally, it should be noted that the managers of factories adopting an e-manufacturing strategy should strongly consider competing on the edge of high-mix, low-volume, custom-engineered manufacturing environments. As the case study at Mobica has revealed, this strategy is particularly useful in emerging nations that are competing with more technologically advanced countries. Of course, the real-time visibility offered via RFID is a significant advantage—and arguably essential—for shop floors across the globe.

Adel Ghannam, PhD, is founder of the consultancy Industrial Systems and Global Enterprise. He is also a professor of management information systems at the Modern Sciences and Arts University in Cairo, Egypt. He may be contacted at adel.ghannam@isg-egypt.net.

Salwa Nassar, PhD, is a professor of computer systems at the Electronics Research Institute in Cairo, Egypt. She may be contacted at salwa.nassar79@gmail.com.

Hesham El Deeb, PhD, is a professor of computer systems and president of the Electronics Research Institute in Cairo, Egypt. He may be contacted at heldeeb@mcit.gov.eg

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