tailieunhanh - Screw threads and Gear Manufacturing Methods

An appropriate liquid-liquid phase separation is critical for the preparation of nanofibers and does not occur in all solvents that’s why selection of solvent and phase separation temperature is crucial for the formation of nanofibers. When the condition are favourable, liquid-liquid phase separation produce three dimensional fibrous structure with nano scaled architecture similar to that of collagen type I, and used in various biomedical applications. Advantage of the phase separation technique is that, it can easily combine with other fabrication technology (Particulate leaching) to design three dimensional structures with control pore morphology. It can also be combined with. | Module 7 Screw threads and Gear Manufacturing Methods Version 2 ME IIT Kharagpur Lesson 31 Production of screw threads by Machining Rolling and Grinding Version 2 ME IIT Kharagpur Instructional objectives At the end of this lesson the students will be able to i Identify the general applications of various objects having screw threads ii Classify the different types of screw threads iii State the possible methods of producing screw threads and their characteristics. iv Visualise and describe various methods of producing screw threads by a Machining b Rolling c Grinding i General Applications Of Screw Threads The general applications of various objects having screw threads are fastening screws nut-bolts and studs having screw threads are used for temporarily fixing one part on to another part joining . co-axial joining of rods tubes etc. by external and internal screw threads at their ends or separate adapters clamping strongly holding an object by a threaded rod . in c-clamps vices tailstock on lathe bed etc. controlled linear movement . travel of slides tailstock barrel compound slide cross slide etc. and work tables in milling machine shaping machine cnc machine tools and so on. transmission of motion and power . lead screws of machine tools converting rotary motion to translation rotation of the screw causing linear travel of the nut which have wide use in machine tool kinematic systems position control in instruments . screws enabling precision movement of the work table in microscopes etc. precision measurement of length . the threaded spindle of micrometers and so on. acting as worm for obtaining slow rotation of gear or worm wheel exerting heavy force . mechanical presses conveying and squeezing materials . in screw conveyor injection moulding machine screw pump etc. controlled automatic feeding in mass production assembly etc. ii Classification Of Screw Threads Screw threads having various applications can be classified as follows .