Permanent Mold Casting Process advantages and disadvantages Advantages

Permanent Mold Casting Process advantages and disadvantages Advantages ü High production rates (over 100/hour) ü Good dimensional accuracy and finish ü Less machining, less skill, lower scrap ü Suitable production quantities in thousands Disadvantages ü Tooling cost higher, longer lead times ü limited materials (selected non-ferrous) ü Limited shape size, size and intricacy (compared with investment casting) ü Tolerances not as good as with investment casting) 1

용융금속에 압력을 가하는 방법 원심 주조법 (Centrifugal casting process) 다이캐스팅 (Die casting process) 정도가 높은 정밀 주형을 이용하는 방법 Shell mold process Investment casting process CO 2 mold process 기타 주조법 진공 주조법 (Vacuum casting process) 연속 주조법 (Continuous casting process) 6

주조법의 명칭 韓國 美国系 英国系 砂型鋳造 Sand casting Gravity Die casting 金型鋳造 Permanent mold casting Low pressure Die casting 低圧鋳造 다이캐스팅 Die casting Pressure Die casting 7

특수주조법 特殊鑄造란, 鑄型은 砂型이 아니고 주로 金型을 이용하며, 용탕의 응고 시에 壓力과 독특한 冷却 方法을 이용하여 제조하는 법을 특수주조라 한다. 8. 1 8. 2 8. 3 8. 4 8. 5 8. 6 8. 7 8. 8 쉘 주형 (Shell molding process) CO 2주형법 (CO 2 mold process) 인베스트먼트법 (Investment casting process) 원심주조법 (Centrifugal Casting Process) 다이캐스팅법 (Die casting Process) 진공주조법 (Vacuum casting Process) 저압주조법 (Low Pressure Casting Process) 고압주조법 (Squeeze Casting Process) 8. 9 석고 주형법 (Plaster Mold Casting Process) 8. 10 쇼 프로세서 (Shaw process) 8. 11 풀 몰드법 (Full mold process) 8

Investment casting in which a wax is surrounded by a ceramic. After the wax is melted and drained, metal is poured into the mold. 14

Investment casting (lost wax casting) (a) Wax pattern (injection molding) (d) dry ceramic melt out the wax fire ceramic (burn wax) DEWAX (e) Pour molten metal cool, solidify Hollow casting : pouring excess metal before solidification (b) Multiple patterns assembled to wax sprue (c) Shell built immerse into ceramic slurry immerse into fine sand (few layers) (f) Break ceramic shell (vibration or water blasting) (g) Cut off parts (high-speed friction saw) finishing (polish) 16

Ceramic shell mold process Lost wax process 작업공정 17

Investment casting method 마그네틱 코어 임펠러 20

Investment casting method 펌프부품 임펠러 21

Investment casting method 21

Semi centrifugal casting centrifuged casting (a) Schematic illustration of the semi centrifugal casting process. Wheels with spokes can be cast by this process. (b) Schematic illustration of casting by centrifuging. The molds are placed at the periphery of the machine, and the molten metal is forced into the molds by centrifugal force. 23

8. 5 다이캐스팅법 (Die Casting Process) Advantages of Die Casting ü High Accuracy with little or no secondary machining operations ü Good surface finish ü Holes as small as 2 mm diameter ü Thin walls possible ü Long die life ü Product material cost low (thin sections) ü High production rates (1000/h) Disadvantages of Die Casting ü High cost of dies and capital equipment ü Narrow range of non-ferrous alloys ü Restricted by size/weight (15 kg Zn, 10 kg Al, 5 kg Mg, 3 kg Cu) 25

Die Casting Examples (a) The Polaroid PDC-2000 digital camera with AZ 91 D die-cast, high purity Mg case. (b) Two-piece Polaroid camera case made by the hot-chamber die casting process 26

Die casting machine의 종류 Cold chamber die casting machine Hot chamber die casting machine 27

Hot chamber die casting 28

Cold chamber die casting 29

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ALUMINMUM COMPONENTS CUSTOMERS 35

ALUMINMUM COMPONENTS CUSTOMERS 36

AUTOMOTIVE ELECTRICIAL 37

8. 6 진공 주조법 (Vacuum casting Process) ü 진공주조 : 용해는 대기 중에서 하고 주조는 진공 하에서 한다. (a) (b) Fig. Schematic illustration of the vacuum casting process (a) Before and (b) after immersion of the mold into the molten metal 38

Low Pressure Casting 41

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Plaster Mold Casting Ceramic Mold Casting Plaster mold slurry : plaster of Paris (Ca. SO 4), talc, silica flour Ceramic mold slurry : silica, powdered Zircon (Zr. Si. O 4) - The slurry forms a shell over the pattern - Dried in a low temperature oven - Remove pattern - Backed by clay (strength), baked (burn-off volatiles) - Cast the metal - Break mold part Plaster mold : good finish plaster : low conductivity => low warpage, residual stress low mp metal (Zn, Al, Cu, Mg) Ceramic mold : good finish high mp metals (steel, …) => impeller blades, turbines, … 62

Expendable Mold Casting - Styrofoam pattern - dipped in refractory slurry dried - sand (support) - pour liquid metal - foam evaporates, metal fills the shell - cool, solidify - break shell part Full mold casting is a technique similar to investment casting, but instead of wax as the expendable material, polystyrene foam is used as the pattern. The foam pattern is coated with a refractory material. The pattern is encased in a one-piece sand mold. As the metal is poured, the foam vaporizes, and the metal takes its place. This can make complex shaped castings without any draft. However, the pattern cost can be high due to the expendable nature of the pattern. 67

풀 몰드법 (Full mold casting process), 消失模型 鑄造法 68