Workpiece Surface Finish Research Articles

Active Machine Tool Controller Requirements for Noise Attenuation

The use of feedback control to regulate the position of the cutting tool relative to the workpiece on a machine tool such as a lathe is examined with respect to the reduction of vibratory noise effects on workpiece surface finish. Both control mode and controller characteristics are examined relative to noise effect attenuation. An examination of system stability (the chatter tendency) is also included as a necessary part of the evaluation of each type of controller that is considered.

Rigidity considerations in fixture design—contact rigidity at locating elements

An apparatus has been designed and developed to investigate deformations taking place at contact surfaces between workpiece and fixture locating elements under the action of steady loads. Test results show, for the three types of locators investigated, that the relationship between deformation and applied load can be represented by a potential function, relevant exponents and coefficients being dependent on workpiece material, surface finish and hardness, also on the area of contact and form of locator. Present investigations do not, in general, confirm the theory of contact between elastic bodies in as far as deformations are concerned; experiment exhibits higher deformation values than those predicted by theory. Closer agreement may be expected to be achieved should the effect of the actual area of contact, the quality of contacting surfaces and the hardness of materials be included in the theory. Further work on the subject is proceeding.