Original Date: 10/07/2002
Revision Date: 01/18/2007
Best Practice : Machining Standards
Using standardized processes and tooling for machining common features on machined parts resulted in less tooling and increased efficiency in the process. Productivity was enhanced while cost and waste was minimized.
Prior to mid to late 2001, General Tool Company (GTC) operated similar to most job shops in the planning and manufacturing of small lot quantities and prototype parts for its customers (i.e., each part was planned from scratch and processed as a unique entity). Numerical control programmers worked with supervisors and machinists to select tooling and cutting parameters on a part-by-part basis. The information gathered was not always captured, documented or shared. Although this approach may have been successful, it was not always conducive to being the most efficient or effective to the hours spent in manufacturing or to the tooling costs. Some of the challenges this approach led to were:
Tool shortages due to lack of standardized tooling and processes
Machining process inefficiencies frequently leading to re-programming
Time wasted to reinvent the wheel with every new job
Inflated tool crib inventory required to support the system
Each job subjected to a new learning curve
Actual cost of the job varying greatly from the estimated cost
GTC’s management determined that a shift in mind set from no-two-parts-alike to commonality of features of parts was required in order to remain competitive in today’s environment. Large manufacturers had for years successfully used standard shop practices and standardized tooling based on common features rather than individual parts. It was reasoned that this approach should work for a job shop as well. GTC’s approach was to divide the universe of milling into eight basic processes: drilling, bore milling, reaming, tapping, boring, profiling, pocketing, and slotting. Standard processing parameters were written, and standardized tooling was selected that would both support each of these processes. The company now had a common tool that engineers, strategists, programmers, and machinists could use to align their thinking. Regardless of its geometry, a part that required profiling would be machined using standardized tooling and methods. Any other part being manufactured that required profiling would follow this same established process. An electronic living document to store the technical organization’s lessons learned was created and electronic interface to the company’s tooling inventory was also established.
The benefits of this standardization of processes and tooling became instantly identifiable which include:
Increased efficiency in programming with fewer processes required to learn and store
Increased efficiency in machining immediately attainable since the machinists are familiar with tooling and techniques
Reduced tool crib inventory with standardized tooling being used for all like processes
Minimized special tooling needs
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