STUDY AND ANALYSIS OF CUTTING FORCES ON OBLIQUE CUTTING OF WOOD

Obilque cutting of wood is an important form of cutting wood. With the developing of woodworking industry, it is widely used in wood machinary processing such as planing, milling, sawing, drilling and so on. This paper takes oblique planing and helix milling of wood as examples. The influences of bevel angle and other factors on the cutting force have been shown. The changing rules of cutting forces have been summarized. On the basis of it, we especially carried out theoretical analysis on the changing rules of cutting forces and discussed the influence of the changing rules on practice.

Oblique Cutting Based Mechanical Model for Insertion Torque of Dental Implant

The insertion torque of a dental implant is an important indicator for the primary stability of dental implants.Thus,the preoperative prediction for the insertion torque is crucial to improve the success rate of implantation surgery.In this present research,an alternative method for prediction of implant torque was proposed.First,the mechanical model for the insertion torque was established based on an oblique cutting process.In the proposed mechanical model,three factors,including bone quality,implant geometry and surgical methods were considered in terms of bone-quality coefficients,chip load and insertion speeds,respectively.Then,the defined bone-quality coefficients for cancellous bone with the computed tomography(CT)value of 235–245,345–355 and 415–425 Hu were obtained by a series of insertion experiments of IS and ITI implants.Finally,the insertion experiments of DIO implants were carried out to verify the accuracy of developed model.The predicted insertion torques calculated by the mechanical model were compared with those acquired by insertion experiments,with good agreement,the relative error being less than 15%.This method allows the insertion torque for different implant types to be quickly established and enhances prediction accuracy by considering the effects of implants’geometries and surgical methods.

Analysis of Shear and Firiction Behaviors in End Milling Process

As a new approach to analyze shear behaviors in the shear plane and chip-tool friction behaviors in the chip-toolcontact region during an end milling process,this paper introduces a method to transform an up-end milling processto an equivalent oblique cutting process.In this approach,varying undeformed chip thicknesses and cutting forcesin the up-end milling process are replaced with the equivalent of oblique cutting ones.Experimental investigationsfor Inconel 718 were performed to verify the presented model.

A guiding oblique osteotomy cut to prevent bad split in sagittal split ramus osteotomy:a technical note

Aim:To present a simple technical modification of a medial osteotomy cut which prevents its misdirection and overcomes various anatomical variations as well as technical problems.Methods:The medial osteotomy cut is modified in the posterior half at an angle of 15°-20°following novel landmarks.Results:The proposed cut exclusively directs the splitting forces downwards to create a favorable lingual fracture,preventing the possibility of an upwards split which would cause a coronoid or condylar fracture.Conclusion:This modification has proven to be successful to date without encountering the complications of a bad split or nerve damage.