|Standards for Machine Tools
Making It All Work Together
by Yusuf Venjara
Making the many components of a huge machine tool work together safely and effectively requires standardization. Yusuf Venjara of Hitachi Seiki USA, Inc., a machine-tool manufacturer, describes many reasons why it is time for the industry to come together and create standards that will increase productivity and safety.
Machine tool technology has progressed over the last 30 years from the dark and dingy machine shop atmosphere to high-tech computerized manufacturing. The large, multi-component operations that manufacture machine components are commonly called CNC (computer numerical control) machines. These are run by controls and computers, which are themselves run by programs and procedures created by manufacturing engineers. What required the turn of a handle or a toolmaker to produce a precisely machined part is now accomplished through data input.
Today, CNC machines produce machine components much faster and more precisely than old methods. The complex design of parts required to produce todays complex machinery would not have been possible without them. In addition, CNC machines and supporting services in the factory have been partly responsible for gains in productivity in the last decade. Installing CNC machines is the norm in manufacturing these days. Even the smallest of shops have a CNC machine to compete in the marketplace.
With such prevalent usage and so many manufacturers making this product, the need for standards is evident, not only for the manufacture and use of these machines, but also their impact on the environment.
Customizing Requires Standardization
Designing a machine tool is like designing an automobile. Engineers design the machine but not all its components. They choose from a variety of sources and build the machine to their specifications. When the required components are built to a certain standard, the machine tool builder may pick and choose the components required to build the machine and be assured of their adequacy for the job. And when a customer buys the machine, he can acquire these standard components from an outside vendor when parts need to be replaced.
Unlike a car buyer who can drive the purchase off the lot, machine tool buyers cannot use the machines they buy without adding things to them. Since a CNC machine makes components that go into other machines or devices, the customer must add components to the machine to produce the specific part he is trying to manufacture. These components include tool holders, tools, fixtures, coolants, and lubricating oils, which can be procured from outside vendors who specialize in making these products. However, if the machine is not made to a standard to accept these components, the customer is locked into buying these components from the machine tool builder. This is not a very desirable solution both for the customer and the builder. Manufacturers are not so large that they can build all components and customers do not want to be tied to one source for all components. The machine has to be made to standard specifications, which allow customers to use the machine with the components they see fit to buy.
In the 1970s and early 80s, a classic case for standards was created by the tool holder in machining centers. The tool holder is the component that goes in the spindle of the machine and holds the cutting tool. In the absence of a standard, each manufacturer made the spindle to its own specifications. No one was wrong in creating these specifications, but customers buying the machine were tied to the builders or their supplier for all the tool holders. As usual, when consumption increased and CNC became a norm in manufacturing, tool holders became a sticking point at the time of purchase. Customers had to buy different kinds of tool holders for every machine. This was not a good solution both practically and economically.
Various parties in the machine tool industry got together and tried to hammer out a standard. After a long time, an acceptable standard was arrived at. It was a standard, but it also allowed for a great deal of variance, which could be used by machine tool manufacturers to suit their individual needs.
Was it the best standard? Many would argue that it was not. But for the last 15 years, the standard has served the machine tool industry very well. Hassles about tool holder compatibility are a thing of the past.
The lesson in this history discourse is that standards definitely help both the manufacturer and the consumer. Standards do not have to be so rigid that they tie everyone down. They can have flexibility built in, allowing manufacturer innovation. A classic example of this is the Windows operating system. Many will argue that it is not the best standard, however it powers the majority of PCs in the world. It might not satisfy the requirements of the experts, but it does the job for most of the lay people who are casual users.
High Speed Machining
Just like everything in this modern world, machine tool technology is evolving. A lot of changes have occurred in the last 30 years and there is more to come. One machine tool technology that has evolved over the last five or six years is high speed machining, which involves machining a part at 10 to 20 times the speed as they are being machined today. With the increase of spindle and cutting speed, a lot of concerns regarding the machine and its accessories are arising. Not only are there issues of component performance but underlying issues of safety and environmental impact. We are treading in unknown areas, where no rules are written down.
The standardized tool holders that served the industry well for the last 15 years are being looked at for their worthiness in such high-speed applications. New types of tool holders are being considered and used selectively. The compatibility of machine tool coolants and oils, which have been used as a matter of course since the foundation of the machine tool business, are now becoming a big issue in high-speed applications. At high speeds, the performance of coolants are different than at normal cutting speeds. Chip removal, which has traditionally been an afterthought, cannot be disregarded in the design phase of high-speed machining applications.
As always, the performance of the tool holders, coolants, and chip removal affects the performance of the machine. The customer automatically looks to the machine tool builder when all these components do not work together, even though the machine tool builder did not supply the components. All of this brings the need for standardization into bolder relief. If there are standards to which OEMs, component manufacturers, and users could turn, many of the variances could be analyzed in a logical manner. This is where ASTM Committee F35 can help in defining the compatibility issues of some of these items.
In this digital age, CNC machines generate a lot of numbers and information, which if retrieved and analyzed properly can provide a wealth of information. However, right now, these machines are islands of information working on their own. To promote productivity, which is the key factor in the strength of the manufacturing sector, these islands need to be integrated, with standard communication and data formats. Not only do CNC machines make machine parts, they are links in the total supply chain, from order procurement to the delivery of goods. Manufacturing has to be looked upon as part of the total enterprise content management.
In todays world of global operations and productivity, safety, and environmental concerns, it makes sense not only to manufacture the part but also to send and receive numerical data about everything in real time. A lot of data is contained in the control; it just needs a standard way of communicating with a standard format. This is more easily said than done.
With all the components of these high-tech and sensitive machines, from spindles, to coolants and lubricants, to data retrieval, there are a great many needs and opportunities for standardization on the factory floor, for decades to come. //
Copyright 2002, ASTM