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Abrasive machining of ductile iron with CBN - 58607 Abrasive machining of ductile iron with CBN

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n 2002 ductile iron accounted for 31%of casting shipments from 13.14 billiontons in the US. Although pressure pipes are a large portion of this marketcomponents for the car, truck and powertransmission sectors account for 27% of these ductile iron shipments [1]. Ductile iron or spheroidal graphite iron (SGI)has many properties such as goodstrength to weight ratio, excellent damping characteristics, good wearresistance and fatigue strength includinggood machinability [2]. Austempered ductile iron (ADI) is thought to offer all thebenefits of ductile iron as well as superiormechanical properties common to many steel forgings and castings with lowermanufacturing costs and offers potentialfor weight savings and associated reduced fuel consumptions costs for example in the automotive industry [3].ADI is thought to machine similar tohigh-strength ductile irons [4]. Typical application areas for ductile iron includecrankshafts, camshafts, piston liners,gears, piston rings, wheel hubs, manifolds, shafts, railway wheels andother applications such as machineframes and suspension brackets.An excellent review was given by Inasakiet. al [5] in 1993 which indicated thedirection of fixed abrasive processingor grinding preferring the term ‘abrasive machining.’ The continued growth anddevelopment of vitrified bonds hasextended the productivity barriers of many high volume automotive andaerospace component producers [6].Central to the success of the rapidly

In this paper by K. Tuffy and M. O’ Sullivan , The performance of a CBN abrasivein an electroplated tool is quantified when high speed grinding ductile iron in terms of specific grinding energy, cutting forces and spindle power requirement. The range of operation of the product was defined in the range of specific material removal rate up to 220 mm

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/mm/s, therefore operating under highefficiency deep grinding conditions. An initial ranking is developed by comparing the performance of this CBN with another commercially available abrasive type, with a different impact strength and thermal stability. The mode of tool failure is different and is identified in this paper. The tool life was defined as the amount of material removed before a specific normal force level of 90 N/mm was reached. It was found there was a direct correlation between force and power and either could indicate the end of tool life once a target value was specified. The tool life of the stronger CBN product was twice that of the other weaker abrasive type, which required higher specific grinding energies and grinding forces over the range of material removal rates studied.

HP cleaning coolant76 L/min @ 50 barLP supply coolant130 L/min @ 9.2 bar
Fig 1a Schematic of grinding arrangement on Blohm Profimat MT 408 xv
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w Fig 1b Close up of surface of electroplated CBN wheel used in this project developing technology is the superabrasive products and product offerings, inparticular with regard to CBN [7]. Theemphasis on processes such as high efficiency deep grinding (HeDG) hasfirmly focused the spotlight on theunexplored potential of monolayer CBN wheels and the performance benefits [8]. The HeDG grinding process has beenthe focus of intensive research from a
INDUSTRIAL DIAMOND REVIEW1/06

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