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design & molding Injection Molding Process Automation Technology for Surviving in a Global Economy By Peter Rucinski, Moldflow Corporation As we know it today, the injection molding industry is in its infancy. It was only during the 1960s that reciprocating screw technology, arguably the heart of the process, became commercially viable. With the advent of the microprocessor, there have been significant advances in process control during the 1980s and 1990s. There have been equally significant advances in screw technology, multi-color molding, insert molding, gas-assisted injection molding, and other niche processes. There have also been major advances in polymer materials, mold making, and of course, predictive analysis tools for avoiding problems before they occur and optimizing every phase of the design-to-manufacturing process. However, in spite of all these advances, the injection molding industry continues to exhibit signs that it is still a very young industry. For example, it remains common to setup and optimize the process using time-consuming and inefficient trial-and-error methods. While molders may be able to obtain acceptable quality parts using this method, the process usually requires constant fine-tuning to maintain quality parts because it was not set up using a scientific method. Failure to setup and optimize using a scientific method normally results in a process that is not robust and therefore, is difficult to control. Beyond the setup, optimization, and control of the process, there are additional injection molding manufacturing tasks that must be performed, optimized, standardized, and integrated across the company-wide enterprise. These additional tasks include, but are not limited to, production scheduling, preventive maintenance, process and production monitoring, statistical process control, statistical quality control, and production reporting. It is also becoming increasingly common for injection molder’s customers to demand value-added operations such as part traceability, while simultaneously demanding per-part price decreases. Facing these challenges, injection molders must not only implement systems and processes to achieve the value-added demands, but also accomplish them cost-effectively while improving the efficiency of their existing operations. This article discusses the various injection molding manufacturing tasks that must be performed, optimized, and implemented across the company-wide enterprise in order for companies involved in injection molding to work smarter and remain competitive in today’s global economy. Injection Molding Manufacturing Execution System Basics It is a well-known fact that once an injection molding operation reaches a threshold minimum number of machines, which is typically about 20, it becomes necessary to implement various production tracking and process monitoring software and hardware tools to effectively manage operations. However, there are inherent problems with many of the tracking and monitoring tools available today, including:
The ideal solution to address tracking, monitoring, and various other tasks required in an injection molding manufacturing environment begins with a single, scalable system supplied by a technology provider recognized for its technological expertise, innovation, financial stability, and support systems. At the core of the single scalable system is a common database that accepts both process and production data. The common database is accessible through a single user interface on desktop PC clients using various modules, depending upon the intended task to achieve. For example, quality assurance personnel might want to validate a recent production run, a manufacturing engineer might be interested in operating efficiencies, and a processing engineer might want to analyze process information to troubleshoot a problem. Enter Moldflow Manufacturing SolutionsTM products. Moldflow Manufacturing Solutions (MMSTM) products comprise a complete suite of tools that can be used for the setup, optimization, and control of the injection molding process, as well as for the monitoring and monitoring-related tasks associated with injection molding equipment, as well as upstream and downstream auxiliary equipment. One of the fundamental components of MMS 1.0 is a common database for the storage and manipulation of all process and production data collected or accessed by any MMS module. Implementing a common database across all modules makes it possible to mix and match various capabilities cost-effectively across multiple pieces of manufacturing equipment. As an example, some machines may require detailed process monitoring while others only need lighter-weight production monitoring. The system is also scalable, allowing machines that initially have only production monitoring installed on them to be upgraded to process monitoring in the future. The remainder of this article discusses the various issues that can be addressed by implementing a system such as Moldflow Manufacturing Solutions. Data Acquisition A core piece of any process or production monitoring system is a data acquisition system that gathers analog and digital signals from manufacturing equipment and sends them to the process/production monitoring system database for use in performing other tasks. A truly scalable system, such as the MMS system, allows data to be collected from a variety of devices, including digital input units only and units that accept both digital and analog inputs. Furthermore, device drivers that allow data to be collected directly from injection molding machine controllers, such as the Ferromatik Milacron XTREEM® NT controller, are also part of the system. The MMS system is configured so that data can be acquired from a heterogeneous environment comprising data acquisition units and devices and stored in a common database for later use. Process Setup 
Once an injection molder makes the decision to implement a system such as MMS to optimize, control, and manage its injection molding operation, there are a number of modules available to solve different manufacturing problems. One of those problems is process setup that involves a machine-mold-material combination. An operator or technician needs to determine a combination of processing conditions to achieve acceptable quality parts. The MMS process setup module offers several benefits:
Process Optimization 
After determining the combination of process parameters to produce an acceptable quality part, it is important to further determine or verify a robust processing window. The MMS system offers a module for performing an automated Design of Experiments (DOE) that builds on the foundation established during the process setup phase. The technology allows users to further optimize the combination of processing parameters to determine a robust, "good parts" processing window. The predefined DOE runs automatically, so no special expertise in statistical process control (SPC) is required for a machine operator to determine a robust, "good parts" processing window quickly. Once this robust processing window has been determined, the process is less likely to go out-of-control and produce out-of-specification parts. Process Control 
Assuming a robust processing window has been determined by using MMS process setup and optimization modules, users can access the process control module to maintain the optimized processing conditions. The MMS process control module allows users to consistently maintain the production process, resulting in reduced reject rates, higher part quality, and more efficient use of machine time. Process Monitoring and Analysis Once a robust processing window has been established and is in control, it is generally desirable to continuously monitor any number of process parameters to identify trends in the data, analyze profile graphs to uncover hidden problems, as well as collect and archive the data for part traceability requirements. All this functionality is included within the MMS process monitoring and analysis module. Production Monitoring Production monitoring normally is associated with tracking data such as part counts, number of good parts versus number of defect parts, defect causes, machine downtime, and machine efficiencies. Typically, it is also possible to derive this information by using a simple digital signal from a piece of manufacturing equipment, which ultimately signals that the machine has cycled. The MMS system includes a production monitoring module that allows for the tracking of the previously mentioned production data, including mechanisms to input scrap causes, downtime codes, job start/stop, lot changes, material consumption, and part quantity adjustment. This capability allows injection molders to measure and track their operations in real time, thereby enhancing critical decision-making. Statistical Process Control Fundamentally, statistical process control (SPC) is a method of monitoring a process during its operation in order to control part quality during production, as opposed to relying on inspection to find problems after the fact. SPC involves gathering and analyzing data about the process itself in near real time, so that necessary action can be taken. This is done in order to identify special causes of variation and other abnormal processing conditions, thereby bringing the process under statistical control and reducing cycle-to-cycle or part-to-part variation. Because of the nature of the injection molding process, it is ideally suited for implementing SPC methods. Therefore, a complete manufacturing solutions system should include a method for performing various SPC tasks. Within the MMS system, there is an SPC module that can be used to apply SPC methods to the injection molding process. Some of its capabilities include:
These are just some of the MMS SPC capabilities available to help injection molders improve their process and maintain greater control over it. Statistical Quality Control Relative to injection molding, statistical quality control (SQC) is the application of statistical techniques to measure and evaluate the quality of a part or process. Within SQC, there is the concept of acceptance sampling, which is the application of statistical techniques to determine whether a population of items should be accepted or rejected based on a sample inspection. Furthermore, "quality measurements" associated with certain characteristics, such as part weight, part dimensions, part warpage, and others, can be assessed. Any or all of these characteristics can be identified as either acceptable or not acceptable. In combination, the measurement of these characteristics, results feedback, and the correlation with SPC data, offers valuable tools for injection molders who aim to achieve or exceed the highest levels of production quality. The SQC module within the MMS system allows SQC data to be entered into the system and recorded in association with shot-numbered process data for correlation purposes in a statistical process analyzer tool. Production Reporting Once a production or process monitoring system is in place, there must be a mechanism for extracting the data collected in a format that is easily communicated to those who require the information. This is accomplished using the MMS production reporting module, which provides the following capabilities:
Production reporting is a valuable and necessary component of any process or production monitoring system as it is the mechanism for providing access to critical information in real time so that informed business decisions can be made. Production Scheduling 
As an injection molder increases the number of machines and molds that are scheduled to run in production, an automated production scheduling system becomes a necessity. It is common knowledge that without a production scheduling system, molders are apt to delay or miss product ship dates. This scenario results in lost time, additional expenses, and dissatisfied customers. The MMS scheduling module provides fast job creation and efficient schedules. The use of previously collected job histories and job templates makes scheduling new jobs or job reruns easy and efficient. The scheduler also allows users to adjust machine workloads to accommodate changes in production or delivery requirements while eliminating scheduling conflicts. Conclusion In today’s global economic environment, injection molders must implement systems and processes to achieve value-added demands cost-effectively while improving the efficiency of their existing operations. Beyond the setup, optimization, and control of the process itself, there are injection molding manufacturing tasks that must be performed, optimized, standardized, and integrated across the company-wide enterprise. These additional tasks include production scheduling, preventive maintenance, process and production monitoring, statistical process control, statistical quality control, and production reporting. Injection molding manufacturing companies must implement the tools required, such as Moldflow Manufacturing Solutions, to achieve these tasks to work smarter and remain competitive in today’s global economy.
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