Real Equipment Performance Monitoring Requires Automation

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In the current manufacturing scenario, production floors or plants are getting fully automated, with equipment which requires minimum human intervention for their operation. Automated machinery however, does not necessarily mean that the process has become automated and we will see why as we carry on. Today, we will address the issue of monitoring equipment performance with or without an MES and try to understand the pros and cons associated with these scenarios.

Before starting with the topic at hand let’s establish a few parameters which will help us understand the topic better. First, organizations purchase expensive, automatic equipment for three major reasons, which are- to reduce manual labor/cost, to increase speed/accuracy of work and to better utilize the resources at their disposal. Second, the value generated by any equipment is a function of its actual operating time and the actual number acceptable goods produced using the same. Third and last, every piece of equipment can be considered to be in different states at any given point of time and to report and record the current state and the transition between various states, regardless if manually or automatically.

Last week we saw the importance of OEE or Overall Equipment Effectiveness as a process performance metric. In that article we had established why OEE is better implemented using an MES application and how manual implementation is more costly, time consuming and inaccurate. We will come back to the subject of OEE towards the end of this article.

An Equipment State can be best understood as the status of the equipment at any given time. Consider a simple sheet-fed, die-cutting machine. Such machines are being applied in numerous operations world-wide basically to cut/punch any substrate in a given/desired shape or size. Let’s say that this equipment is automated i.e. once it is started by pressing a switch it will continue to cut, unless stopped by pressing a Stop button or by any problem that causes an alarm to occur, such as the substrate being of an incorrect size.

Now, the equipment can be in any of the four mentioned states at a given point of time,State 1- IdleState 2- RunningState 3- Stopped and State 4- Under Maintenance. To be able to understand the efficiency with which the cutting machine is performing or being used, it is very important for the plant management to know three things at any point of time: 1) The current state of the machine, 2) The number of transitions between the states and 3) The total time when the machine was running without any issues.

For the ease of calculation and understanding, an Equipment State Model can be used to represent different states of the cutting machine. Once the management is informed of these metrics, they can evaluate the equipment performance in terms of uptime, utilization and even complex metrics such as the OEE.

The example discussed above is just to illustrate the nature of equipment states and their use in management decision making. However, in many industries there are actually standards which specify state models, such as the Semiconductor industry, which has the SEMI E10 Specification for Definition and Measurement of Equipment Reliability, Availability, and Maintainability (RAM). Organizations use these models/standards to improve their performance and to ensure that the states are changed as reliably as possible.

Now, the way in which most companies record and change equipment states using such models is by manually conducting the process. This way of manually recording states and changing them, actually defeats the purpose of the entire exercise of having state models and recording state transitions and changes. Let’s see why.

Any modern equipment like the automated die-cutting machine mentioned above, operates at a very high speed, and changes states very fast (e.g. start-stop operations while waiting for material, consumables, intervention from an operator, etc.) and it’s virtually impossible that someone manually reflects such changes in the system at the same pace and accuracy. Even when the machine does not change states fast, there is a natural delay in recording, when data is recorded manually. Also a big disadvantage in manual recording/changing of equipment states is the fact that there is always a chance of false/erroneous reports. A logical question which comes to mind with manual recording for automated equipment is “Why spend millions automating the plant by purchasing state-of-the-art equipment, when the underlying intent is to keep it manual and thereby slow and inaccurate?”  There are obviously clear and evident flaws in using manual methods for automated equipment.

At this juncture it’s worthwhile to discuss the reason an MES should be used not only to change states of the equipment but also record the states and the transitions of states. The MES uses the function generally referred to as the Resource Tracking function to track equipment data. But, even in the MES state changes may be performed manually and this may lead to a continuous false reporting of uptime. Here it is vital to understand more from a management’s perspective that the MES is best utilized and can give most accurate information when it is used to record and report data directly from the equipment.

The operations staff may try to avoid this scenario as it may expose that the actual uptime is far lower than what was being reported. But to gain maximum value out of the expensive equipment purchased, it is imperative that the MES be used for recording Equipment Performance information. So as soon as state changes-changes in the MES are done based on direct equipment information, thereby the reliability is much higher. We have already seen in the article about OEE, how the MES can be configured to collect time-based equipment data, calculate required metrics and report them automatically and at regular intervals.

To sum up the purpose of this article is to make decision makers and top management of manufacturing organizations realize the importance of complete automation (in this article, from an equipment monitoring perspective). Complete automation occurs when automatic equipment is used in tandem with automated systems such as the MES to record, report and analyze information, generated automatically from the process itself. When MES is used to gather Equipment data the most accurate, definitive and real-time picture of the process is revealed, and although what this picture reveals might not be to the operations personnel’s liking, it will definitely help generate higher value from the process and help improve the overall process effectiveness.

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