Design and Development of a Fixture for Split-Nut of Injection Molding Machine

Abstract

A fixture is a work-holding device used in manufacturing for quick and easy set-up of workpiece, to hold workpiece securely, to position it correctly with respect to machine or tool and support it during machining/ milling operation. A Fixture has a direct in uence on product quality, productivity, and cost. Hence it is widely used in manufacturing. Split-Nut is used in plastic injection molding machine especially for high capacity maxima series machines (550 to 3200 tons). It gives clamping force to hold mould (moving) platens in close condition during high injection forces. Machining at Degree of Split-Nut halve part on horizontal machining center without the help of fixture takes too much set-up time. Split-nut is available in different sizes for the different tonnage capacities of the injection molding machine. The purpose of this dissertation is to design and develop a fixture for different sizes of Split-Nut. And also to reduce set-up time for machining of Split-Nut. Locating and clamping principles are considered while designing a fixture. Concepts of a fixtures are modeled using CAD software PTC CREO 5.0. Calculations of manual machining forces and cost analysis are carried out. The validation of a design of a fixture for static structural analysis are carried out using ANSYS workbench. The best possible design are selected by studying the results of ANSYS structural analysis and Cost analysis. Selected design is safe under all boundary conditions. Flanged nut is used in fixture design for clamping purpose and safe under loading condition. The Developed fixture is used in horizontal machining center and it has been found that set-up time reduce from 45 minutes to 15 minutes and also easy loading of a split-nut in fixture block reduced the chances of damage the Split-Nut.