Concept of MTBF of numerical control machine tool (average time to failure)

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  • source:KAIHER CNC Machining
MTBF namely average time to failure, english is " Mean Time Between Failure " , specific it is to show the product arrives from breakdown the next time the average time of breakdown, it is the dependability index that measures a product (use at malfunctioning only the equipment that via repair or changing the spare parts can continue to work or system) , the unit is " hour " . Numerical control machine tool is commonly used the mensurable index that it regards dependability as. The numerical value of MTBF is how of numerate, assume the MTBF of a computer is 30 thousand hours, run this computer 30 thousand hours to detect those who come out continuously? Not be of course, otherwise so much product wants not to detect with a few years. The computational method that MTBF is worth, at present the most current authority level is MIL-HDBK-217 (center of analysis of dependability of American department of defense and Rome lab put forward and make occupation standard, use technically at war industry product) , GJB/Z299B (Chinese military standard) with Bellcore (the occupation standard that AT&T Bell lab puts forward and makes civil product MTBF) . What basically consider in MTBF computation is every failure rate of yuan of parts of an apparatus in the product. But because parts of an apparatus is in,different environment, different use condition issues its failure rate to be able to have very big distinction, it is so when computational dependability index, must consider these factors. And these elements cannot be passed almost have consideration artificially, but have the aid of is like MTBFcal and its giant parameter warehouse at software, can reach MTBF is worth easily. If the plant that every Nature's engineering makes 3 asks barrier of successive movement, without reason leads P(t) = 24 hours 99% above, criterion the MTBF of the machine tool must be more than 4500 hours. MTBF5000 hour asks to the product line that makes by the numerical control machine tool of different amount taller, more complex, only station machine tool discusses only here: If of the failure rate of lead plane and numerical control system than for 10: 1 (the dependability of numerical control system should compare mainframe tall quantitative class) , the MTBF of numerical control system is about to be more than 50 thousand hours, and the MTBF of among them numerical control device, main shaft and body of drive ministry classify must be more than 100 thousand hours. Actually, we need not pay close attention to MTBF value how to be calculated, want to know to choose MTBF to be worth expensive product only, will bring taller competition ability to us. Of course, also not be MTBF the cost has been jumped over higher, cost of taller machine tool also jumps over dependability tall, chose to go reliably moderately according to real need. CNC Milling