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| Understanding the X-Factor |
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Understanding the X-Factor: A Values Based Productivity Tool
In a perfect factory, there is no variation in the entry of product to the floor. Every minute of work is spent working on the product. There is no down time, no paperwork, no difficult versus easy product. As soon as the product is finished in one area, work begins at the next area. It is like product flowing on a conveyor belt. This perfect factory has perfect input and perfect output – one equals the other. The X Factor of this mythical factory is 1!In a world-class factory, the time spent working on the product is only one third of the total cycle time. The product release is still constant, predictable and in line with the capabilities of the factory, but there is paperwork, delay and sometimes machine breakdown. Still, all of these variations are kept to a minimum. A world-class factory brings fear to those that are forced to compete with them. They know how to keep the variations in their process to a minimum. People that work there feel good about their job and their future. The X Factor of this very real factory is 3!
In a struggling factory, the scheduling and release of product is likely to be highly variable because there are always problems to deal with that cause extra work and loss of output. Extra product is released to the line in amounts exceeding capabilities. Product is expedited throughout the process. WIP builds up at constriction points regularly. Orders are often late and customers are often upset. This factory often accepts work that they are not prepared for, or capable of manufacturing. People that work in this factory do not feel good about their job or their future. The X Factor of this COMMON factory is greater than 10, and likely to be higher than 15!
If you work in a factory that has a high X Factor, you are probably one that doesn’t work hard to reduce your variability. You spend most of your time just fighting fires or doing damage control. Analysis and Action are not part of the daily work scheme. There is hope for those that work in this kind of factory. There are things that they can do to improve their own departments and their factory. They would be surprised at how much they can improve their situations by simply working on the right things. We aren’t talking about rocket science here. We are talking about a simple, common sense approach to process improvement. ANY factory can reduce its X Factor by 50 to 75% within one work quarter!
X Factor is a shortened way to say multiplication factor. Quite simply, it tells the user how many times his or her Raw Process Time (RPT) can be multiplied to equal the Total Cycle Time (TCT) of a unit of product for their department or their plant. Using the perfect factory as an example, all of the work completed is spent working only on the product. Cycle Time = Raw Process Time. Raw Process Time can be described as the amount of time that a unit of product is physically worked on. When product moves quickly, RPT is very close to TCT. When product sits around waiting to be worked on, TCT is increased and X Factor goes up.
To calculate the X Factor of a factory, you would take the Total Cycle Time of the product from the front to the end of manufacturing, and divide it by the Total Raw Process Time accumulated from the front to the end. To calculate the X Factor for a department or work center, you would take the daily output of that department, and divide it by the RPT of that department. Although it is important for management to understand the X Factor of a plant, the greatest use of X Factor comes from using the calculation in departmental productivity analysis. There, it is a powerful analytical tool that can make a huge difference in the ability of a company to deal more effectively with the ups and downs of manufacturing.
Not included in RPT are setup times, time spent on paperwork before, during and after product process time and transport time into, or within the area. Also not included are tasks such as counting product when it comes into the area or is about to be transported out. While these tasks require completion and are certainly important, it is also important that the time spent on them is held to a minimum. When more than one unit of product is worked on simultaneously, at one station, the amount that is worked on simultaneously becomes the “unit” for RPT, but not for TCT. TCT is still calculated for a single unit, as is TAKT. If you count your output in units, use units in your calculations.
Remember, Raw process time is associated with your product, whatever it is. In a factory that produces panels, you look at the total amount of time that you actually work on a panel to determine RPT. The cycle time that you are calculating is the total cycle time of one panel. In a test department, you don’t actually change the functional capabilities of a panel, but you do work on it. Do not confuse RPT with value add time. If you are working on a panel, you are accumulating RPT. If the panel has not yet been shipped, it is accumulating cycle time even if it is just sitting around waiting.
