1/1/2002 | 3 MINUTE READ

The Challenges Of CNC

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The impact computer technology has had on machine tools has changed all areas of machining and manufacturing. Where initially only certain machines such as lathes and machining centers were equipped with computer control, today CNC technology has entered the world of highly flexible and highly productive equipment. In addition, new machine design concepts have made it possible to integrate different types of machining processes into one process on one machine.

This is possible because of the computers that control today's CNC machines. Where 30 years ago, the biggest challenge was to make the most out of the limited abilities of a machine, today the biggest challenges are our abilities to program, set up and operate these machines. The success of companies today not only depends on new CNC equipment, but also on the training and professional development of their staffs in new "CNC" skills. New crafts include innovative job processing methods, organizational planning and preparation skills, and the ability to supervise a more complex machine tool.

As a result of the flexible and multi-process machine tool systems, the previously defined boundaries of machine tool categories have been removed. More production-type equipment is now available with some or full CNC.

Vertical moving spindle chuckers have many innovations. These machines are also called self-loading chuckers because the moving headstock with the spindle can be used to present the part to the (fixed) tool for machining, and it can pick up the part directly from a conveyor and transport it in and out of the work area. The fixed tools have allowed integration of non-traditional process capabilities. Beyond the skills required for programming machining and metalcutting processes, these CNC machines require imagination and ingenuity.

In addition to CNC making machines economical for low volume work, its increasing power has allowed the development of high production equipment with full CNC. In some cases, more than 50 axes or motors are needed for controlling high production multi-slide and multi-spindle machines. The advantages are flexibility and tool offsets, and there is no longer a need for specially built, dedicated equipment. Instead, standard off-the-shelf CNC machines are used for high volume applications.

New equipment also requires different skills. As a result of the programmability and precision of modern CNC machine tools, a shift has taken place that has moved the emphasis and skill focus away from the machine into the area of organization, preparation, planning and programming.

In "old world" technology, part and process quality and capability were largely dependent on the skill and experience of the machine operator. Today the real machine operators are the so-called programmers who envision new processes, select the best tooling and write the programs that enable the machines to efficiently produce high quality parts.

Once a certain process is tested and proven, a repeat setup is simple, provided that all information regarding production means is properly documented, prepared and fully reproducible.

CNC excels at producing part quality at high Cpk levels on short notice in varying lot sizes. Different means of production and improved setup tools have pushed sophistication sometimes beyond the limits of the manageable. The early stages of CNC saw many striving for unattended lights out production with fully automated part loading, gauging, force monitoring the "MAP" system and other futuristic technologies. This was followed by a single piece flow process with manual loading, breaking down the process into a few easy operations.

Eventually we learned that everything is a compromise. The key to success is in the happy medium. We now produce much better part quality and more sophisticated workpiece shapes at a lower cost. In the end, we learn that we still cut metal, make chips and use drills, taps, turning tools and milling cutters as we always did, except now we do it "the CNC way".