CHAPTER 1
1. Introduction
When Engineering or IT managers realize the need to develop a new or replacement computer system to support their manufacturing processes, they begin by closely examining current system designs. This sometimes means forming a team and sending members on trips to distant places to see systems designed for other manufacturers. Business analysts are usually members of such a team because they play an important role in extracting information, understanding requirements, and documenting methods. The overall approach, at best, enables designers to apply new technology towards the development of similar systems. Generally, the analytical approach leads designers to understand current requirements and methods of existing designs. The deployed process typically creates the limitations found in older designs and is unlikely to produce a new design with improved abilities. Many find this process acceptable because they believe technological advancements will drive improvements. Regardless, understanding and documenting current designs is an important first step. However, to improve manufacturing processes, strategists need to examine and compare design methodologies.
Any comparison process of design methodologies is not as simple as pushing a tray and selecting items cafeteria style. It is more like an architect designing a unique superstructure for the very first time. Creating the blueprints is difficult. This is the situation most system strategists find themselves in when they begin to define the requirements of an MES. What does the architect rely on when designing the blueprints for an uncommon superstructure? Education helps, but having a framework document backed by experience is very useful. The Cardinal Cornerstone to MES Success directs system strategists to make foundational design decisions first. This enables designers to build on that foundation towards the development of a highly reliable MES.
There have been numerous books and articles written on the topic of Manufacturing Execution Systems, but the emphasis always seems to describe what these systems can or should do. Indeed, what these systems promise should drive the justification for their development and implementation. Making good on these promises is another story. This explains why, up until now, MES books and articles have a focus on managing automation or providing some nebulous form of supervisory control. To break this paradigm, this book focuses on enabling MES designs to fulfill their promises by arming designers with the information needed to direct automated manufacturing processes.
It does not matter how designers develop an MES or how many times they refine their applications; inaccurate information limits the performance of the system performance. Information accuracy varies depending on the way MES applications collect and feed information to manufacturing processes. If strategists overlook these aspects, manufacturers will need to contend with MES designs that have many operational anomalies that will simply annoy or create significant production losses for manufacturers.
So how do new MES applications get accurate, reliable information to and from manufacturing processes? How can these applications really improve product quality, accurately deliver data, track part movements, detect errors, identify product locations, and support sequential and non-sequential processes while insuring data models remain synchronized with the physical realities of manufacturing? These are just some of the questions addressed in this book. The concepts described are essential for developing a reliable or fundamentally sound MES.
Before any MES can effectively direct a manufacturing process, integrated designs must adapt to machine control fundamentals. Adapting to these fundamentals provides the ability to synchronize computer applications with mechanical machine sequences and moving parts. This ability comes from developing and deploying integrated designs that focus on using the hidden DNA of machines. The DNA revealed in this book, contains the genetic instructions used in the development of all functioning control systems and therefore, all reliable MES designs.
Manufacturers of assembled parts have been trying to stay competitive by investing and using computer systems to support their company's production processes. These systems deliver and collect data from electrical equipment and machine control systems. The ability to deliver information to control systems reliably enables machine designers to develop flexible machines with the power to produce a wide variety of parts. The expanded ability to reliably collect information enables computer applications to feed information back to improve manufacturing processes.
MES is the label sellers of systems are applying to the next generation of computer-based manufacturing systems. Manufacturing Engineering and IT managers too often believe that sophisticated or clever labels warrant the cost to develop new systems. Some also believe that generic "off-the-shelf" solutions may not target the business needs of their manufacturing processes. To ensure a new system efficiently targets and executes a manufacturing process, developers must plan to customize off-the-shelf designs.
Manufacturers should only develop new MES designs if they can articulate and measure expected process improvements. This includes the ability to improve costs associated with implementing or supporting their existing systems and processes. To begin, manufacturers must determine whether their current computer systems are executing processes efficiently. If their systems have many physical interconnections to communicate data between applications, the answer is no! If a proposed new system is merely replacing the role of an existing system, manufacturing strategists must recognize they are already using an MES.
To avoid any confusion associated with various labels, the following terms define two types of computer-based manufacturing systems:
* Manufacturing Support System: a computer system designed to perform a standalone set of tasks.
* Manufacturing Execution System: a computer system designed to perform many otherwise standalone sets of tasks.
The obvious difference between the two systems is the application scope. Manufacturing support system (MSS) designs use many standalone systems to separately collect and/or deliver the information needed to support individual tasks. Manufacturing execution system (MES) designs use one integrated set of system components to collect and deliver the information needed to support manufacturing processes. This design characteristic makes it easy for all MES applications to share information.
Efficiently designed MES applications that support automated processes enable manufacturers to reduce operating cost. They do this by minimizing the number of system connections, hardware components, and personnel needed to support a large variety of MSS applications. As an added benefit, these new designs reduce manufacturing downtime costs by eliminating redundant functions, minimizing the opportunity to confuse operations personnel, and increasing their awareness of the manufacturing process.
For some manufacturers, MES designs have little to no effect on automated manufacturing processes. Finished MES designs have applications that interact with customers, supplier programs, or operations personnel. These kinds of designs are critical to executing manufacturing processes, but are outside the scope of the fundamentals described in this book.
For automated equipment, the term "MES" has many different meanings depending on the entities involved with manufacturing. For machine suppliers, an MES is merely a computer system used to help sell more machines. For a manufacturer, an MES is a computer system used to improve the quality, increase the number, and lower the cost of manufactured products.
Machine suppliers are likely to sell more machines when they can prove they have an MES that can coordinate large manufacturing processes. The associated sales pitch often emphasizes enabling manufacturing managers to oversee production. These MES designs usually have the ability to show the statuses of machines and the locations of parts. Machine suppliers add animated screen interfaces to enable production managers to see representations of moving machines and parts. Although these features seem important to machine suppliers, they do little to improve product quality or lower manufacturing costs.
Machine supplier provided MES designs need to connect to other systems in order to facilitate communications at two interface points. The first interface point enables their MES to retrieve and queue part, order, schedule, and build information. The manufacturer's system provides this information before the process acts on the physical parts. From there, most designs use data queues to coordinate build processes. When parts exit the machine supplier's production domain, the MES uses a second interface point to send back part built status information. These features and their simple ability to connect to a manufacturer's IT infrastructure, makes them attractive. This is especially true when the manufacturer's IT systems are too expensive to deploy, or they are not meeting the strategic needs of new processes.
In order to stay competitive, manufacturers need to embrace the need to provide a full-featured MES design that meets the strategic needs of their company. This includes the operational needs of manufacturing managers, the cost reduction needs of product and process planners, and the part quality needs of corporate personnel who work to sell and service finished products. Deploying a machine supplier's limited feature MES design makes it difficult for manufacturers to gain the full-featured benefits needed to meet all strategic directives. Commingling a supplier's MES with a manufacturer's MES is problematic. Most of the problems relate to having overlapped or redundant applications, all needing access to the base set of events and information. The following terms describe the many feature roles of today's standalone computer-based MSS applications:
* Part Scheduling: a suite of applications that deliver part order information to a manufacturing process to ensure machines build the correct sequence, quantity, and mix of parts.
* Part Identification: a suite of applications that enable remote applications to make requests in order to retrieve part information.
* Error Prevention: a suite of applications that work to detect build errors introduced into the manufacturing process.
* Mistake Proof: a suite of applications that work to prevent users from making errors, thus eliminating the introduction of build errors.
* Parts Traceability: a suite of applications that gather information about the lineage and route of subparts used to produce a fully assembled main part.
* Quality Inspection: a suite of applications that allow inspectors to record and buy off on part defects to support repair and routing processes.
* Machine Monitoring: a suite of applications that support device diagnostics, production counts reporting, fault predictions, bottleneck analysis, and station performance alarming.
* Material Logistics: a suite of applications that monitor part/subpart consumption, and control the offline flow of parts to and through a manufacturing process.
* Product Tracking: a suite of applications that provide quality inspectors, support personnel, new applications, and customers with part location information.
* Product Routing: a suite of applications that enable a manufacturer to control the flow of parts and subparts through their manufacturing process.
* Transaction Logging: a suite of applications that store process event information, thus enabling users and applications to identify manufacturing trends, root causes problems, and new "data mining" applications.
* System Reporting: a suite of applications that enable operations personnel to produce a multitude of metric, status, and part location reports.
Many of the companies that were first to develop computer systems for manufacturing, focused their efforts on designing applications to provide operations personnel with information, not automated machines. Relay controlled machines were uncomplicated, and could not easily connect to computer systems. Early systems made information available to personnel who interacted with printers and simple displays. Personnel visually extracted information from these devices, and then manually interacted with machines and assembly processes. Over time, these companies went on to enhance their computer systems by increasing their ability to connect to more and more devices. Eventually machine control sophistication increased, and computer systems added automation controllers to their suite of supportable devices.
Today, many manufacturing companies continue to make large monetary investments in an effort to continue to evolve their MSS systems. Most manufacturers have done so while continuing to ignore the evolution of automation controllers. These companies are now stuck in a support paradigm where the systems originally designed for operations personnel are not properly adapting to automated machine processes. As a result, the companies using evolved MSS applications are not keeping pace with their competitors.
Many IT organizations are responsible for controller-based applications that execute in the manufacturing environment. Most applications request, translate, and disseminate product information for process machines and IT devices. Other controller-based applications are responsible for collecting and storing process information. The low-level application and device support focus is forcing IT organizations to be data integrators and preventing them from becoming data suppliers. At the same time, the many standalone systems are making it difficult for IT developed data mining applications that can cross-reference data from various controller-based applications. Those manufacturers who rely on IT data integrators are beginning to recognize increased manufacturing costs associated with redundant system integration, and support services. The costs are redundant because both engineering and IT organizations are performing similar work activities in support of the same machines.
So how can IT organizations move from being data integrators to data suppliers and miners? Some IT and engineering managers believe the answer is new thinking and technology. This usually equates to having the next generation of university graduates apply the latest technological innovations. Most of these managers fail to recognize that technology solutions only enable new designers to replicate today's legacy systems. Any newly developed system will have the same functional limitations and cannot provide any substantial operational advantages to manufacturers. Furthermore, the reliance on new development methods does not mean an IT organization can escape the need to thoroughly understand process requirements before they begin designing a system.
To change the system paradigm, manufacturing engineering and IT organizations must evaluate the fundamental strategies associated with current MSS designs. The evaluation process will force them to recognize poor design fundamentals and the cornerstone strategies needed to correct them. To aid in the evaluation process, this book describes and analyzes many fundamental design strategies.
