Applying Value-Added Principles
Value-added principles are quite simple and can be applied to all forms of manufacturing. Though this may be oversimplifying to some extent, there are only three basic task types in value-added terms.
Value-added principles are quite simple and can be applied to all forms of manufacturing. Though this may be oversimplifying to some extent, there are only three basic task types in value-added terms. Everything you and your people do fall into one of just three categories.
First, a value-added task is an activity for which your company is paid. Since your company only makes money when you ship your product, a value-added task in manufacturing is any task that furthers the completion of your product. To be more specific, pouring castings, sand-blasting, forging blanks, painting, deburring, machining, molding, plating, polishing, cleaning, and assembling are all examples of value-added tasks. Narrowing this down to the CNC environment, it is only when your machines are actually in the process of cutting parts that your shop is making any money for the company.
Second, there are many necessary support tasks that must be performed in your CNC environment. Though they are quite important, do not directly further the completion of the workpiece and thus do not make your company any money. Necessary support tasks can be administrative, clerical or manufacturing-related. Administrative support tasks include accounting, payroll, and human resources. Necessary support tasks more related to the CNC environment include programming, setup, program verification, inspection, tool maintenance and so on.
And third, anything left over—that is, not a value-added task or a necessary support task—is waste. Examples of waste tasks include duplication of effort, mistakes, scrapping workpieces, and inconsistencies in usage of any kind (inconsistent quality, setup times, cycle times, and so on).
Based on the three simple task types, there are four ways to improve the utilization of your CNC environment. In all cases, the best way to evaluate potential improvements is to study your people performing their daily activities.
Eliminate waste. In most companies, this provides the biggest chance for potential improvements, especially if you have never considered how much waste exists in your shop. In the February 1997 Tech Talk column we discussed waste elimination.
Enhance the value-added tasks. In the CNC environment, this means find ways to machine workpieces faster or better. In essence, it involves implementing many principles of a cycle-time reduction program. This is accomplished by improving the process, fixturing, and cutting tool selection and by optimizing your programs' execution time (cutting conditions, rapid motions, tool changes, and so on).
Eliminate non-essential support tasks. This is a bit of a gray area since, as we just said, any task that does not further the completion of the workpiece and that is not necessary is waste. With this approach, you'll be trying to find ways to move tasks currently in the category of necessary support to waste, and then you'll eliminate the task.
This may simply sound like a play on words. But it is one of the most powerful concepts in value-added principles. Do not be too quick to give up on eliminating costly necessary support tasks. You may find that there are many of them in your ownCNC environment that can be eliminated with little more than ingenuity and determination. And believe it or not, given unlimited resources, there is no necessary support task (especially in your CNC environment) that cannot be eliminated.
Many of the necessary support tasks related to program zero assignment, for example, can be eliminated based upon today's control technology and making qualified setups. Your setup people may be measuring the program zero point location and manually entering the corresponding values into fixture offsets, even though you make qualified setups. This is one necessary support task that can easily be moved into the category of waste—and eliminated.
Facilitate necessary support tasks. Just because it may be possible to eliminate a necessary support task does not mean it is feasible. It may not be possible to justify the related effort and cost. When this is the case, you must make the task as easy to perform as possible.