Force-controlled steadyrest system
AssigneeEnergy-Adaptive Grinding, Inc.
InventorRoderick L. Smith
Life of this patent
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Abstract
A method of grinding a workpiece which is susceptible to deflection and/or deformation when grinding is carried out by relatively infeeding a grinding wheel to keep the wheel face and work surface in relative rubbing contact at an interface region, the method comprising continuously determining the force exerted by the wheel on the workpiece at the interface region as grinding conditions change, continuously applying to the workpiece at least one counterbalance force which in equivalent effect is opposite in sense to the determined force, and variably controlling the counterbalancing force to maintain its effective magnitude equal to the magnitude of the determined force.
Claims33
A method of grinding a workpiece which is susceptible to deflection and/or deformation when grinding is carried out by relatively infeeding a grinding wheel to keep the wheel face and work surface in relative rubbing contact at an interface region, said method comprising
- continuously determining the force exerted by the wheel on the workpiece at the interface region, independently of the position of the workpiece surface, as grinding conditions change,
- continuously applying to the workpiece at least one counterbalance force which in equivalent effect is opposite in sense to said determined force, and
- variably controlling said counterbalance force to maintain its effective magnitude equal to the magnitude of said determined force.
A method of counterbalancing the variable grinding force F.sub.N applied to a workpiece by a rotating grinding wheel, in a direction normal to the face of the grinding wheel, during the course of grinding action resulting from the rotating grinding wheel being relatively infed with relative rubbing contact of the wheel face and the workpiece surface, said method comprising
- continuously determining the variable force F.sub.T exerted by the wheel on the workpiece in a direction tangential to the wheel face at the region of relative rubbing contact,
- continuously determining that force component F.sub.Tmr, in part making up the tangential force F.sub.T, which acts to remove material from the workpiece,
- continuously determining that force component F.sub.Tf, in part making up the tangential force F.sub.T, which acts to create heat due to friction of said relative rubbing contact,
- continuously determining the variable force F.sub.N exerted by the wheel on the workpiece in a direction normal to the wheel face at the region of relative rubbing contact, and
- applying to the workpiece a counterbalancing force F.sub.S which is maintained equal to, and opposite in direction to, said force F.sub.N.
A method of counterbalancing the variable grinding force F.sub.T applied to a workpiece by a rotating grinding wheel, in a direction tangential to the face of the grinding wheel, during the course of grinding action resulting from the rotating grinding wheel being relatively infed with relative rubbing contact of the wheel face and the workpiece surface, said method comprising
- continuously determining the variable force F.sub.T exerted by the wheel on the workpiece in a direction tangential to the wheel face at the region of relative rubbing contact,
- applying to the workpiece a counterbalancing force F.sub.S which is maintained equal to, and opposite in direction to, said force F.sub.T.
A method of determining, from instant to instant, the changeable normal force F.sub.N which a grinding wheel exerts on a workpiece during a grinding operation, the material removal work function constant K.sub.m for the material of the workpiece being known and the sliding coefficient C.sub.f of friction for the workpiece and wheel materials being known, said method comprising
- determining and signaling the magnitude of the total tangential force F.sub.T exerted by the wheel on the workpiece in a direction tangential to the wheel surface at the region of wheel-workpiece engagement,
- determining the effective tangential force F.sub.Tmr exerted by the wheel on the workpiece in a direction tangential to the wheel at the region of wheel-workpiece engagement, and whose effect is to remove material from the workpiece, by computing the value of ##EQU29## where M' is the volumetric rate of material removal from the workpiece, and S.sub.r is the relative surface velocity of the rubbing contact of the wheel and workpiece, and
- determining a value indicative of said normal force F.sub.N as equal or proportional to the difference between said total tangential force F.sub.T and said tangential material removal force F.sub.Tmr, divided by said coefficient C.sub.f of friction.
A method of grinding a workpiece which is restrained by at least one primary steadyrest located to oppose the tangential force applied to the workpiece by a grinding wheel, said method comprising
- continuously urging said steadyrest against the workpiece with a controllable force,
- determining the tangential force exerted on the workpiece at the grinding interface, and
- controlling said steadyrest force to urge said steadyrest against the workpiece with a force that varies as a function of said tangential force, whereby said steadyrest continuously counterbalances said tangential force on the workpiece.
Dependencies are inferred from the claim text.