14-09-2012, 12:07 PM
CNC-MILLING PROGRAM FOR SQUARE PROFILE TEMPLATE
CNC-MILLING.doc (Size: 2.93 MB / Downloads: 70)
ABSTRACT
CAM Software is used for development of computer numerical control programs based on the applications of CNC machines. Advanced programming techniques have been incorporated with in CNC controllers by CNC machine tool manufacturers to facilitate the flexibility in production of the job.
In this Project, CNC Programming of Square Pass profile Template on CNC Milling machine was under taken. This template is used as gauge while turning profiles on rolls.
INTRODUCTION
Vizag Steel Plant , the MINIRATNA , is the gigantic integrated steel plant, is the Pride of steel , Producing saleable steel with many number of sections like Squares , Rounds , Rebar’s, Angles , Channels , I – Beams , Wire rods etc. These sections are produced by rolling Blooms / Billets in Rolling Mills.
ROLL SHOP & REPAIR SHOP is heart of the mills serving the needs of mills like supply of GUIDES and TURNED ROLLS. Turning of Profiles on rolls are being done in Roll Turning shop – I & II on C N C Lathes. The design of profiles is done in Roll pass design section by the Engineers. The programs for the profiles are developed by Programmers in programming section according to the design. After turning Profiles on Rolls , they will be checked by using templates for shape and Size. In roll turning shop template is used as gauge.
Earlier these templates are conventionally cut by using fitting Techniques, i.e., marking the shape of the profile on metal sheet according to the dimensions using scribers, dividers ,steel rule, punch, hack - saw and files, etc.
Steel Melting Shop:
It is provided 3 basic oxygen converters (Top blown LD converter) and six nos. of four strand continuous casting machines. Each converter with a volume of 133 cubic meters is capable of producing 150 tons of liquid steel per heat. The SMS has got potential to produce 3 million tons of liquid steel (considering two operating converters and 10000 heats per annum per operating converter) .To mix and store hot metal received from various heats of blast furnaces and ensure smooth and uninterrupted supply of the same to the converter shop, two nos. hot metal mixers of 1300 tons capacity each are provided in the shop.
The hot metal from Blast Furnace is received in the mixer department and stored in the hot mixer. Required quantity of hot metal is taken out from the mixer and sent to the converter shop (Metal transported by torpedo ladle is directly taken into converter). Hot metal and scrap are charged in to converter with the help of over head crane. The charge in the converter is then blown with 99.5% pure oxygen with the help of water cooled oxygen lance and pre-calculated amounts of fluxes like lime, iron ore, fluorspar are added into the converter during blowing. After 16 to 18 minutes of blow, a sample and temperature of steel from the converter is taken and if found good, liquid is lapped into the steel ladle. After rinsing the liquid steel with argon gas, the steel is cast in the form of blooms in the continuous casting machine. The CC blooms are cut into required sizes and stored in the bloom storage yard cost wise and quality wise. These blooms are further processed in the rolling mills into various salable products.
Special Features:
a) Most notable feature of the shop is 100% continuous casting of the steel into blooms.
b) Process control computers, dynamic control with sub lance, converter gas cleaning plant based on suppressed combustion system for recovering and utilizing converter gas as fuel.
c) Use of torpedo ladle cars for the supply of hot metal to the converter (a facility first time in India) and equipping 100% steel teeming ladles with the slide gate system.
d) Automatic process control and monitoring system of CCM.
e) Liquid steel is cast in six nos. of four strand bloom casters.
Computer controls in NC:
There are a number of problems inherent is conventional NC which have motivated tool builders to seek improvements in NC. Some of them are part programming mistakes use of fragile punched tape as input, hard-wired controller and reader all these problems led to enhancements and extensions of NC technology
Computer Numerical control:
Computer numerical control is a NC system that utilizes a dedicated, stored program computer to perform some or all of the basic numerical control functions. Here punched tape and tape reader are used once to enter the program. Once it is entered, it is stored in the computer. New system options can be incorporated in to the NC controller simply by re-programming the unit. Because of their capabilities CNC is often referred to as “soft wired NC”.