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HAND SCRAPING SETS THE FOUNDATION FOR CNC MACHINING ACCURACY AND LONG-TERM STABILITY

HAND SCRAPING SETS THE FOUNDATION FOR CNC MACHINING ACCURACY AND LONG-TERM STABILITY
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HAND SCRAPING SETS THE FOUNDATION FOR CNC MACHINING ACCURACY AND LONG-TERM STABILITY - 1

HAND SCRAPING SETS THE FOUNDATION FOR CNC MACHINING ACCURACY AND LONG-TERM STABILITY Hand scraping allows for production of more parts, of higher quality, over a longer time frame, reducing lifetime cost of ownership and cost-per-part. EXECUTIVE SUMMARY HIGHLY PRODUCTIVE MACHINES THAT LAST A LONG TIME ALWAYS YIELD THE LOWEST COST-PER-PART. Hand scraping is a practice that has lost its luster for many machine tool builders. Because of the associated costs in time and maintaining skilled labor, it’s an art that has largely been abandoned. At Okuma however, hand scraping is meticulously performed on every machine we build. That’s because there’s no substitute for hand scraping when it comes to maintaining high levels of CNC machining accuracy and sustaining a long, stable and productive life for your machine. Every Okuma is hand scraped on each mating surface – involving six or more of the machine’s components. The craftsmen who perform hand scraping are carefully trained, and tap into their experienced, intuitive sense of how to fine-tune the unique characteristics of each individual machine. Why go to all this trouble? Because there’s no better way to ensure that tight tolerances are maintained consistently, and that this level of CNC machining performance will be sustained for years to come. As for lifetime cost of ownership – highly productive machines that last a long time always yield the lowest cost-per-part.

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HAND SCRAPING SETS THE FOUNDATION FOR CNC MACHINING ACCURACY AND LONG-TERM STABILITY - 2

OKUMA HAND SCRAPING THE ESSENTIAL OBJECTIVES OF HAND SCRAPING Hand scraping sets the foundation for productive CNC machining. It is performed with the following objectives in mind: Accuracy Scraping is done to align components within millionths of an inch, allowing for consistently-held, tight tolerances. Flatness Eight to ten contact points per square inch are created to prevent rocking, add balance when tightening, and to allow for true flatness in parts. Oil Pockets Some machine surfaces have oil injected onto them. Scraping allows for creation of oil pockets, which hold oil on the...

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HAND SCRAPING SETS THE FOUNDATION FOR CNC MACHINING ACCURACY AND LONG-TERM STABILITY - 3

OKUMA HAND SCRAPING HAND PUSHING, “BODY POWER STROKES,” AND CURVED SCR APING ARE PERFORMED AS NEEDED TO MA XIMIZE THE EFFICIENCY OF THE MACHINE TOOL’S OPER ATION. For all machine tool builders, machine components are fundamentally comprised of castings. However molding these castings is not always a consistently repeatable process. Okuma recognizes this and utilizes hand scraping to ensure that the machine tool starts out with a solid, rigid foundation. There are uncontrollable process variables in casting such as slight changes in base materials, mold release agents, temperature and...

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HAND SCRAPING SETS THE FOUNDATION FOR CNC MACHINING ACCURACY AND LONG-TERM STABILITY - 4

OKUMA HAND SCRAPING REDUCED COST OF OWNERSHIP HAND SCR APING IS USED ON EVERY MACHINE BUILT BY OKUMA BECAUSE IT IS ESSENTIAL TO CREATING A SOLID, EFFICIENT MACHINE TOOL FOUNDATION. Clearly, hand scraping adds some cost to the machine building process. However, by fine-tuning the machine so that it operates in balanced harmony rather than creating wear and tear on itself and on parts, more parts, of higher quality, are produced, and the machine lasts longer. Okuma does not embrace a “disposable parts, disposable machine” philosophy. We do hand scraping because we know that lifetime cost of...

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