Tham khảo tài liệu 'machining and monitoring strategies part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Machining and Monitoring Strategies 501 a Die-sinking contours with ball-nosed end mills reduces the residual staircase effect on the resulting machined profile but this depends upon cutter directional passes i Variable cutter pass direction ii Single cutter pass direction b Ball-nosed end mill geometry the cutter coatings to improve hot hardness when machining hardened steel at high-speed Where Dc Tool diameter mm Dc Tool diameter at a set Doc mm ap axial Doc mm a p pick-feed or step-over distance mm . Relationship of different insert coatings - for hot hardness w hen machining hardened tool steel. DIE-CASTING NON-FERROUS PIPE-COUPLINGS Figure 247. By utilising a ball-nosed cutter geometry for die-sinking sculptured surfaces this reduces finishing stock needed to be subsequently removed. Courtesy of Sandvik Coromant 502 Chapter 9 Sculptured Surface Machining -with NURBS Prior to a discussion on the application curve-fitting with Non-Uniform Rational Bezier-Splines - NURBS for short it is worth a brief review into the background as to why there has been a wide-ac-ceptance of them for machining operations involving sculptured surfaces. The technique of curve fitting is not new it was devised in the 1960 s where indirect methods were found making it relatively easy to manipulate these curves - without recourse to modifying the different equation parameters that defined the sculptured surface. In a typical system a complex curve geometry would be comprised of several discrete curves - termed a spline equally a surface is simply a curve with an extra dimension. Thus for curve-fitting the cubic method is particularly suited although a modified cubic approach that can accommodate the uneven spacing of nodes - the start and end points -has particular benefits when digitising surfaces. In France Bezier who at that time was working for the automotive company Renault was intrigued by car body design and found the point-and-slope technique for curve-fitting rather crude
