Skip to main content

MANUFACTURING PROCESS - INVESTMENT CASTING PROCESS


INVESTMENT CASTING PROCESS

THE ROOT OF THE INVESTMENT CASTING PROCESS, THE CIRE PERDUE OR “LOST WAX” METHOD DATES BACK TO AT LEAST THE FOURTH MILLENNIUM B.C. THE ARTISTS AND SCULPTORS OF ANCIENT EGYPT AND MESOPOTAMIA USED THE RUDIMENTS OF THE INVESTMENT CASTING PROCESS TO CREATE INTRICATELY DETAILED JEWELRY, PECTORALS AND IDOLS. THE INVESTMENT CASTING PROCESS ALOS CALLED LOST WAX PROCESS BEGINS WITH THE PRODUCTION OF WAX REPLICAS OR PATTERNS OF THE DESIRED SHAPE OF THE CASTINGS. A PATTERN IS NEEDED FOR EVERY CASTING TO BE PRODUCED. THE PATTERNS ARE PREPARED BY INJECTING WAX OR POLYSTYRENE IN A METAL DIES. A NUMBER OF PATTERNS ARE ATTACHED TO A CENTRAL WAX SPRUE TO FORM A ASSEMBLY. THE MOLD IS PREPARED BY SURROUNDING THE PATTERN WITH REFRACTORY SLURRY THAT CAN SET AT ROOM TEMPERATURE. THE MOLD IS THEN HEATED SO THAT PATTERN MELTS AND FLOWS OUT, LEAVING A CLEAN CAVITY BEHIND. THE MOULD IS FURTHER HARDENED BY HEATING AND THE MOLTEN METAL IS POURED WHILE IT IS STILL HOT. WHEN THE CASTING IS SOLIDIFIED, THE MOLD IS BROKEN AND THE CASTING TAKEN OUT.
THE BASIC STEPS OF THE INVESTMENT CASTING PROCESS ARE 
  1. PRODUCTION OF HEAT-DISPOSABLE WAX, PLASTIC, OR POLYSTYRENE PATTERNS
  2. ASSEMBLY OF THESE PATTERNS ONTO A GATING SYSTEM
  3. “INVESTING,” OR COVERING THE PATTERN ASSEMBLY WITH REFRACTORY SLURRY
  4. MELTING THE PATTERN ASSEMBLY TO REMOVE THE PATTERN MATERIAL
  5. FIRING THE MOLD TO REMOVE THE LAST TRACES OF THE PATTERN MATERIAL
  6. POURING
  7. KNOCKOUT, CUTOFF AND FINISHING. 



References :- www.nptel.iitm.ac.in
Labels:

Comments

  1. Investment Castings30 September 2013 at 12:59

    Trident Steels handles a wide variety of metals, such as stainless steels, wear-resistant steels & so on, to produce top-quality Stainless Steel Investment Castings in all common alloys.
    for more details:
    http://www.tridentinvestmentcastings.com/

    ReplyDelete

Post a Comment

Popular posts from this blog

DOM MANUAL / B-TECH / MECHANICAL / KUK - TO FIND THE SPEED AND TORQUE OF DIFFERENT GEARS IN AN EPICYCLIC GEAR TRAIN.

OBJECTIVE: TO FIND THE SPEED AND TORQUE OF DIFFERENT GEARS IN AN EPICYCLIC GEAR TRAIN. SPECIFICATIONS : 1.       GEAR TRAIN : SUN GEAR : 14 TEETH 2.       PLANT GEAR: 21 TEETH (2 NOS.) 3.       INTERNAL GEAR WITH : 56 TEETH TORQUE MEASUREMENT ·          INPUT TORQUE – MOTOR CURRENT CALIBRATED FOR MOTOR TORQUE. ·          PLANT CARRIER - PULLEY OF 50 MM DIA AND SPRING BALANCE. ·          INTERNAL GEAR - PULLEY, 120 MM DIA AND SPRING BALANCES. Ø   BOTH PULLEYS ARE PROVIDED WITH ROPE OF 12 Ø   MM DIA Ø   DRIVE MOTOR - 1HP DC MOTOR RPM MOTOR OPERATING ON 220 VOLTS Ø   50 HZ SUPLLY, DRIVING THE SUN GEAR. CURRENT(AMPS) TORQUE 1.00 0.5 1.20 1.5 1.40 2.5 ...
359 comments
Read more

MANUFACTURING PROCESS - DRAFT OR TAPER ALLOWANCE

DRAFT OR TAPER ALLOWANCE BY DRAFT IS MEANT THE TAPER PROVIDED BY THE PATTERN MAKER ON ALL VERTICAL SURFACES OF THE PATTERN SO THAT IT CAN BE REMOVED FROM THE SAND WITHOUT TEARING AWAY THE SIDES OF THE SAND MOLD AND WITHOUT EXCESSIVE RAPPING BY THE MOLDER. FIGURE  SHOWS A PATTERN HAVING NO DRAFT ALLOWANCE BEING REMOVED FROM THE PATTERN. IN THIS CASE, TILL THE PATTERN IS COMPLETELY LIFTED OUT, ITS SIDES WILL REMAIN IN CONTACT WITH THE WALLS OF THE MOLD, THUS TENDING TO BREAK IT.  FIGURE  IS AN ILLUSTRATION OF A PATTERN HAVING PROPER DRAFT ALLOWANCE. HERE, THE MOMENT THE PATTERN LIFTING COMMENCES, ALL OF ITS SURFACES ARE WELL AWAY FROM THE SAND SURFACE. THUS THE PATTERN CAN BE REMOVED WITHOUT DAMAGING THE MOLD CAVITY.  PATTERN HAVING DRAFT ON VERTICAL EDGES DRAFT ALLOWANCE VARIES WITH THE COMPLEXITY OF THE SAND JOB. BUT IN GENERAL INNER DETAILS OF THE PATTERN REQUIRE HIGHER DRAFT THAN OUTER SURFACES. THE AMOUNT OF DRAFT DEPENDS UPON THE LENGTH OF THE...
2 comments
Read more

ELECTROCHEMICAL MACHINING (ECM)

ELECTROCHEMICAL MACHINING (ECM) INTRODUCTION:- Electro chemical machining (ECM) is a method of removing metal by an electrochemical process. It is normally used for mass production and is used for working extremely hard materials or materials that are difficult to machine using conventional methods. Its use is limited to electrically conductive materials; however, this includes all metals. ECM can cut small or odd-shaped angles, intricate contours or cavities in extremely hard steel and exotic metals such as titanium, carbide etc. ECM is often characterized as "reverse electroplating," and is similar in concept to electrical discharge machining in that a high current is passed between an electrode and the part, through an electrolyte material removal process having a negatively charged electrode (cathode), a conductive fluid (electrolyte), and a conductive work piece (anode); however, in ECM there is no tool wear. The ECM cutting tool is guided along the desired ...
53 comments
Read more