Casting is a fundamental manufacturing process where molten metal is poured into a pre-formed mold cavity. After cooling and solidification, it forms a final product known as a “casting.” Currently, the most common casting methods include: sand casting (most versatile), investment casting (highest precision), die casting (optimal efficiency), permanent mold casting (best cost-effectiveness), centrifugal casting (specialized for cylindrical parts), and lost foam casting (preferred for complex structures). Each method has its own characteristics, and the selection should be based on a comprehensive evaluation of key factors such as material properties, production volume, part complexity, precision requirements, and budget.
Although there are numerous casting processes to choose from, selecting the most suitable one for your project requires a systematic understanding of their principles, advantages, disadvantages, and application fields. This guide will provide an in-depth look at the major casting processes, helping you make an informed decision for your next casting project.
Core Advantages & Universal Elements of Casting
Four Key Advantages
The enduring success of casting processes lies in their unique advantages:
- Capable of producing complex geometries as single pieces, including internal cavities and flow channels that are difficult to achieve with other manufacturing methods.
- Offeringsignificant cost benefits in large-scale production, reducing material waste and assembly processes.
- Adaptable to a wide range of materials and part sizes, from gram-level to ton-scale components, parts can be produced in quantities ranging from grams to tons.
- Establishing the foundation for high-volume and efficient manufacturing which is a core means of industrialization.
Key Casting Terms Explained
Before delving deeper into casting processes, it’s essential to understand these core terms:
- Pattern: The physical prototype of the casting, whose shape and size directly determine the final form of the mold cavity.
- Core: A prefabricated component used to form cavities or holes inside a casting, which is usually destroyed or removed after the casting has solidified.
- Gating System: A complete channel that guides molten metal to fill the mold cavity, typically including gates, runners, risers, etc.
- Cope and Drag: The two primary halves that together form the complete mold cavity.
- Parting Line: The interface where the cope and drag mold halves meet, often leaving a visible seam or minor flash on the casting.
- Draft: A slight tilt angle is designed on the vertical wall surface to facilitate the smooth removal of the casting from the mold.
- Near-Net Shape: Describes a casting whose as-cast dimensions and surface finish are already very close to the final specifications, requiring minimal additional machining.
General Casting Process Flow Analysis
Although casting methods vary, most processes follow a basic flow consisting of six key steps:
Step 1: Mold Design and Fabrication
Mold design serves as the blueprint phase for casting, requiring critical calculations for shrinkage allowance, draft angle design, and gating system layout.
Based on the design, different casting processes employ distinct mold fabrication methods.
Sand casting creates sand molds through molding, investment casting produces ceramic molds by slurry coating, while die casting and permanent mold casting utilize CNC machining or similar techniques to manufacture metal molds.
Step 2: Metal Melting and Preparation
Raw metal materials are heated to a molten state in furnaces, with strict control over melting temperatures.
Typically, 400–800°C for low-melting-point alloys like aluminum, magnesium, and zinc, and 1,100–1,600°C for high-melting-point alloys such as iron, copper, and steel.
Degassing and refining agents are used to remove gases and impurities from the molten metal, ensuring high purity.
Step 3: Mold Cavity Filling
In this stage, molten metal is filled into the mold cavity via gravity pouring or pressure injection.
Key parameters such as filling speed, pressure, and temperature must be precisely controlled according to the casting structure and process requirements.
The molten metal must fill all areas of the cavity smoothly and continuously to avoid defects like turbulence, interrupted flow, or cold shuts, while gases in the cavity are promptly discharged through the venting system.
Step 4: Solidification Process
After the molten metal is filled into the mold, it enters the critical solidification stage, which directly affects the internal quality and mechanical properties of the casting.
A directional solidification path is established from the far end of the casting to the riser through proper mold design, cooling system layout, and riser placement.
Controlling the appropriate solidification rate can effectively refine the grain structure and prevent defects such as shrinkage and porosity.
Step 5: Demolding of the Casting
Different demolding methods are applied based on the mold type: disposable molds like those in sand casting are broken to retrieve the casting; investment casting uses vibration for shell removal; permanent mold (metal mold) casting employs ejector mechanisms for automated demolding.
After removal, the casting undergoes a preliminary inspection immediately to confirm the absence of defects like mold sticking or scratches, preparing for subsequent processing.
Step 6: Post-Processing and Inspection
The demolded casting requires comprehensive post-processing, including removal of gates and risers, grinding of flashes and burrs, surface cleaning via shot blasting or sandblasting, heat treatment to enhance mechanical properties, and surface treatments such as painting or electroplating.
The quality inspection phase employs various methods, including visual checks, dimensional accuracy measurements, mechanical property testing, and non-destructive testing, like X-ray or ultrasonic inspection.
Summary of Casting Process
The following article will systematically analyze the principles, application areas, advantages, and disadvantages of 13 main casting processes, to serve as a technical reference for your process selection:
Sand Casting
Process Principle
Based on the gravity pouring principle, this process uses wooden or metal patterns to form part cavities in sand molds.
Silica sand is bonded with clay, resin, or other binders to create disposable molds.
Molten metal fills the cavity under gravity, and the sand mold is destroyed to obtain the casting after solidification.
Want to learn more about the sand casting process? Click the link to read this article: Sand Casting Guide: Process, Materials, Design & Defect Solutions
Application Fields
- Heavy Machinery: Structural components like machine tool beds, large gears, and equipment base frames
- Power Equipment: Housing components such as engine blocks, transmission cases, and hydraulic valve bodies
- Infrastructure: Water pipelines, architectural steel structure joints, and bridge supports
- Metallurgical Equipment: Wear-resistant parts like crusher frames, grinding discs, and large bearing seats
Sand Casting Process
Advantages and Disadvantages
|
Advantages |
Disadvantages |
|
Low initial investment cost, simple pattern making, suitable for small-batch production |
High surface roughness, typically requiring extensive post-machining |
| Extremely wide material compatibility, capable of processing various high-melting-point alloys and special steels |
Poor dimensional accuracy, with significantly larger tolerance ranges than precision casting methods |
|
Capable of producing castings with extremely large sizes, indispensable in heavy equipment manufacturing |
Low production efficiency, with complex and time-consuming molding processes |
| Flexible process adjustments, adaptable to different products by simply changing patterns |
Harsh working environment with notable dust and noise pollution issues |
| High recyclability of used sand, resulting in low comprehensive material costs |
Difficult to control the internal density of castings, prone to porosity and shrinkage defects |
Investment Casting
Process Principle
The investment (lost-wax) casting process involves creating a fusible wax pattern using a wax injection machine.
Refractory material is then coated on the surface of the wax pattern in multiple layers to form a ceramic shell.
After high-temperature dewaxing, a complete cavity is obtained. After pouring and cooling, the shell is knocked off to obtain precision castings.
Want to learn more about the investment casting process? Click the link to read this article: Investment Casting Guide: Process, Design, Materials & Applications
Application Fields
- Aerospace: High-temperature load-bearing components like engine turbine blades, fuel nozzles, and guide vanes
- Medical Devices: Biocompatible parts including orthopedic implants, dental abutments, and minimally invasive surgical instruments
- Defense Equipment: Precision components such as missile guidance parts, fuse mechanisms, and armored vehicle transmission parts
- Industrial Equipment: Corrosion-resistant parts, including pump casings, impellers, valve fittings, and food processing molds
Investment Casting Process
Advantages and Disadvantages
|
Advantages |
Disadvantages |
| Achieves dimensional accuracy of CT4-6 with near-net-shape complex geometries |
Multi-step process (pattern making, shell making, dewaxing) results in long lead times of 3-5 weeks |
|
Surface roughness of Ra 1.6-3.2 μm significantly reduces machining requirements |
High per-unit cost limits the primary application to premium sectors like aerospace and medical |
| Capable of producing intricate internal features and thin walls down to 0.5mm |
The maximum part weight is typically limited to 50kg due to wax pattern strength constraints |
|
Material utilization exceeding 90% with minimal machining allowance |
Labor-intensive process with significant manual operations |
| Compatible with difficult-to-machine materials, including superalloys and titanium alloys |
Requires specialized wax handling equipment and environmental controls, demanding substantial initial investment |
Shell Mold Casting
Process Principle
This process utilizes resin-coated sand (a mixture of thermosetting resin and quartz sand).
When the sand comes into contact with a heated metal pattern, the resin cures, forming a thin, rigid mold shell.
Two of these shell halves are assembled to create the complete mold cavity, which is then filled with molten metal via gravity or low-pressure pouring.
Want to learn more about the shell mold casting process? Click the link to read this article: Shell Mold Casting: Process, Materials, Design Tips & Applications
Application Fields
- Automotive Manufacturing: Engine components like engine crankshafts, camshafts, connecting rods, and turbocharger housings
- Hydraulic Components: High-precision pressure-bearing parts such as high-pressure pump bodies, manifold valve blocks, and hydraulic motor housings
- Construction Machinery: Heavy-duty structural parts including transmission gears, wet clutch housings, and steering knuckles
- General Machinery: Basic connectors and supports like heavy-duty bearing housings, high-pressure flanges, and hydraulic pipe fittings
Shell Mold Casting Process
Advantages and Disadvantages
|
Advantages |
Disadvantages |
| Dimensional accuracy can reach CT7-9 with a superior surface finish |
Resin content in the coated sand reaches 3-6%, which leads to higher material costs |
|
Lower sand-to-metal ratio (<3:1) reduces waste disposal by ~60% |
The metal pattern requires sustained high working temperatures (200-300°C), increasing energy costs |
| High molding rate (60-120 molds/hour) for significantly improved productivity |
The metal pattern requires precision machining, resulting in initial investments 2-3 times higher than conventional sand casting |
|
Enables ~20% reduction in wall thickness for lightweight design |
Limited by the metal pattern size, generally suitable only for medium/small castings weighing <100kg |
| Excellent sand flowability replicates fine features down to 0.8mm |
Resin decomposition at high temperatures generates fumes, requiring environmental controls and further increasing initial investment |
Plaster Mold Casting
Process Principle
Plaster mold casting uses plaster as the primary molding material.
By pouring plaster slurry around the master mold, the micro-expansion properties of plaster during solidification are utilized to accurately replicate the mold’s shape.
After drying and dehydration, the plaster mold forms a porous cavity that can perfectly reproduce the fine texture of the master pattern surface.
After pouring and cooling, demolding is performed using water blasting or mechanical methods.
Application Fields
- Artistic Casting: Large and medium-sized sculptures, architectural decorative components, and replicas of museum artifacts
- Jewelry: Precious metal rings, inlaid pendants, customized metal ornaments
- Precision Manufacturing: Instrument housings, micro-gear transmission components, optical equipment brackets
- Cultural and Creative Products: Limited edition commemorative coins, metal badges, high-end office gifts, and other small-batch cultural and creative products
Plaster Mold Casting Process
Advantages and Disadvantages
|
Advantages |
Disadvantages |
| Excellent surface finish (Ra 0.8-1.6μm), achieving near-mirror quality |
Low plaster strength limits mold life to typically under 20 uses, requiring frequent mold replacement |
|
High replication accuracy, reproducing fine details down to 0.1mm |
Only suitable for non-ferrous metals with melting points below 1100°C (aluminum, tin, copper alloys) |
| Uniform cooling rate ensures dimensional stability with minimal deformation (<0.1%) |
Long process cycle: 2-4 hours for plaster setting, plus 8-12 hours for drying |
|
Ideal for small batches of refined parts with relatively low development costs |
Expensive imported plaster materials result in higher per-unit costs than sand casting |
| Environmentally friendly with biodegradable plaster and simple disposal |
Poor mold permeability can cause gas entrapment and misruns in thick sections |
Permanent Mold Casting (Metal Mold Casting)
Process Principle
This process uses mold steel to manufacture reusable metal molds.
Liquid metal fills the mold cavity under the action of gravity or low pressure, and achieves directional sequential solidification through the excellent thermal conductivity of the metal mold.
Molds are typically equipped with water cooling systems, ejector mechanisms, and special coatings to precisely control thermal balance and ensure smooth demolding.
Application Fields
- Automotive Manufacturing: Engine pistons, aluminum alloy wheels, brake calipers, transmission housings
- Home Appliance Industry: Structural components like A/C compressor housings, washing machine drum supports, vacuum cleaner volutes
- Power & Electrical Equipment: Standardized parts such as motor end covers, switchgear enclosures, insulator flanges
- General Machinery: Basic structural components, including hydraulic valve blocks, pump housings, bearing seats
Permanent Mold Casting Process
Advantages and Disadvantages
|
Advantages |
Disadvantages |
| High productivity with mold reuse capability of 30,000-50,000 cycles |
High mold material and manufacturing costs, 5-8 times the initial investment vs. sand casting |
|
Consistent dimensional accuracy (CT6-8) with excellent surface quality |
Limited by mold opening, challenging for deep-cavity parts with complex internal structures |
| Fine, uniform grain structure from rapid cooling improves mechanical properties by 15-25% |
Mold design requires complex thermal balance systems, extending development to 1.5-2 months |
|
Clean, environmentally friendly process without dust pollution, common in sand casting |
Requires precise mold temperature control systems and strict process parameter debugging |
| Material utilization exceeding 85% with significantly reduced gating system volume |
Metal molds have a thermal fatigue lifespan, necessitating regular maintenance protocols |
Gravity Die Casting
Process Principle
Using a metal mold, the filling and shrinkage process is completed entirely by the gravity of the molten aluminum itself.
Through a precisely designed gating system that works in conjunction with the mold temperature field, the molten aluminum is ensured to fill the cavity smoothly in a laminar flow state, and effective sequential solidification conditions are established, thereby obtaining high-quality castings with a dense structure.
Want to learn more about the gravity die casting process? Click the link to read this article: What Is Gravity Die Casting Process?
Application Fields
- Automotive Manufacturing: Key structural components like aluminum alloy wheels, engine cylinder heads, steering knuckles, and suspension brackets
- Aerospace: Engine accessory housings, airborne equipment brackets, flight control components
- Industrial Equipment: Hydraulic valve bodies, compressor cylinders, transmission system housings, large machinery bases
- Power Equipment: Motor end covers, switchgear enclosures, insulator flanges, transformer housings
- General Machinery: Basic components such as pump bodies, bearing seats, gearboxes, and equipment brackets
Gravity Die Casting Process
Advantages and Disadvantages
|
Advantages |
Disadvantages |
| Smooth filling process with laminar metal flow minimizes gas entrapment |
Relatively long production cycle; time from filling to demolding impacts overall efficiency |
|
Relatively simple mold structure without complex pressurization systems reduces tooling cost |
Gating system design critically affects quality, requiring optimization by experienced engineers |
| Ideal for thick-walled aluminum castings, yielding dense microstructure and excellent mechanical properties |
Limited by gravity filling capability; challenging for complex, thin-walled structures |
|
Good process stability with relatively straightforward production control leads to low rejection rates |
Dimensional accuracy is typically CT8-9, lower than pressure die casting standards |
| Long mold service life, suitable for multiple reuse, ideal for batch production |
Limited automation level, primarily reliant on manual operation, resulting in higher labor costs |
Low-Pressure Casting
Process Principle
Low-pressure casting uses a direct connection between a sealed, heat-preserving furnace and the mold to smoothly press molten aluminum into the mold cavity under a pressure of 0.01-0.05 MPa.
The molten aluminum fills the mold from bottom to top under pressure and completes the solidification under pressure, holding, achieving effective sequential solidification, and pressure feeding.
Want to learn more about the low pressure die casting process? Click the link to read this article: What Is Low Pressure Die Casting?
Application Fields
- Automotive Manufacturing: Aluminum wheels, engine cylinder heads, brake master cylinders, steering knuckles, suspension control arms
- Aerospace: Engine casings, turbine blades, aircraft structural components, missile bodies, satellite brackets
- Industrial Equipment: Hydraulic valve blocks, compressor housings, pump bodies, gearbox housings, large equipment bases
- Power Equipment: High-voltage switchgear enclosures, insulating supports, transformer housings, circuit breaker components, cable connectors
- General Machinery: Transmission housings, bearing seats, equipment bases, gearboxes, connecting flanges
Low Pressure Casting Process
Advantages and Disadvantages
|
Advantages |
Disadvantages |
|
Smooth, controllable filling from bottom up minimizes turbulence and oxide formation |
Complex equipment requiring pressure maintenance and sealing systems increases investment and maintenance costs |
| Solidification under pressure yields dense microstructure, superior mechanical properties, and air-tightness |
Relatively long production cycle due to required pressure holding time limits efficiency |
|
High material utilization (>95%) with minimal gating system waste |
Molds require specialized sealing and cooling systems, increasing complexity and manufacturing difficulty |
| Fully automatable with excellent process consistency and reliable quality |
Narrow operating window demands precise control of pressure and temperature parameters |
|
Suitable for complex thin-walled parts with good surface finish and dimensional accuracy |
Strict molten metal purity requirements necessitate auxiliary refining and filtration equipment |
Die Casting
Process Principle
Die casting uses high-strength mold steel to make precision molds, and molten aluminum is injected into the mold cavity at high speed under high pressure of 30-150MPa.
The aluminum liquid completes the filling and solidifies rapidly in an instant, and the ejection mechanism realizes automatic demolding, completing one production cycle.
Want to learn more about the die casting process? Click the link to read this article: What Is High Pressure Die Casting Process?
Application Fields
- Automotive Manufacturing: Key components such as engine housings, transmission cases, steering gear housings, and oil pump bodies
- Electronics & Telecommunications: Mobile phone frames, laptop casings, 5G base station heat sinks, and connectors
- Home Appliances: Washing machine tubs, air conditioner compressor housings, microwave oven cavities, vacuum cleaner parts
- Daily Use Hardware: Door lock housings, tool casings, bathroom fittings, furniture hardware
- Industrial Components: Pump housings, instrument casings, machine covers, automation parts
Die Casting Process
Advantages and Disadvantages
|
Advantages |
Disadvantages |
| High production efficiency (60-120 parts/hour), ideal for mass production |
Complex, precision molds require long development lead times (1.5-2 months) and high initial investment |
|
Excellent dimensional stability and part consistency, with tolerances within ±0.05-0.1mm |
Limited to low-melting-point non-ferrous metals like aluminum, zinc, and magnesium |
| Superior surface finish (Ra 1.6-3.2μm), significantly reducing secondary machining |
High-speed filling can trap air, causing internal porosity that compromises mechanical properties |
|
Capable of producing thin-walled (≥2.0mm) complex parts for lightweight design |
High maintenance costs for hydraulic and control systems require specialized technicians |
| High automation allows one operator to manage multiple machines, reducing labor | High mold costs make the process less competitive for low-volume production |
Vacuum Die Casting
Process Principle
Building upon conventional die casting, this process integrates a vacuum system that reduces cavity pressure to 5-10 kPa before injection, significantly decreasing the gas content within the cavity.
Molten aluminum then fills the cavity in a vacuum environment, effectively preventing gas entrapment and yielding castings with superior density.
Application Fields
- Automotive Manufacturing: Body structural parts, door frames, seat frames, battery trays, anti-intrusion beams
- Aerospace: Engine components, avionics housings, spacecraft structures, navigation equipment brackets
- Electronics: Laptop housings, server components, communication device enclosures, heat sink substrates
- Industrial Equipment: Hydraulic system components, robotic structural parts, precision instrument elements, automation equipment frames
Vacuum Die Casting Process
Advantages and Disadvantages
|
Advantages |
Disadvantages |
| Significantly reduces internal porosity, achieving porosity rates below 2-3% |
High equipment investment cost; the vacuum system increases the machine price by over 50% |
|
Enables full T6 heat treatment, improving tensile strength by 20-30% |
Complex vacuum system maintenance with extremely stringent demands for mold and machine sealing |
| Markedly improves metal fluidity, making it ideal for large, complex thin-wall parts |
High process control difficulty, requiring operation by experienced, specialized technicians |
|
Greatly enhances weldability and surface treatment capability, boosting yield rates |
More complex mold structure increases tooling cost by 20-30% compared to standard dies |
| Mechanical properties approach forged levels, allowing substitution for some forged parts |
Relatively longer cycle time due to the additional vacuum evacuation step |
Squeeze Casting
Process Principle
Squeezing casting is the process of injecting a certain amount of aluminum liquid into the mold cavity and applying a high pressure of 100-150MPa during the solidification process of the casting, so that the molten aluminum completes the crystallization process under pressure.
This process combines the advantages of casting forming ability and forging mechanical properties, refining grains through high-pressure action, and eliminating traditional die casting defects.
Want to learn more about the squeeze casting process? Click the link to read this article: A Brief Overview of Aluminum Squeeze Casting Technology.
CEX’s Patented Squeeze Casting Process
CEX Casting holds a patented squeeze casting process and self-developed squeeze casting equipment, enabling us to provide customers with one-stop solutions.
If you are looking for aluminum alloy casting products with strong mechanical properties or excellent airtightness, please contact us for professional technical guidance and a free quote.
You can also click here to view our squeeze casting page to learn more about our capabilities.
The following video shows the squeeze casting workshop and workflow at CEX Casting:
Squeeze Casting Workshop at CEX Casting
Application Fields
- Automotive Manufacturing: Steering knuckles, control arms, hubs, brake calipers, suspension ball joints, drive shaft couplings
- Aerospace: Landing gear components, engine mounts, missile casings, aircraft structural parts, turbine discs
- Industrial Equipment: Hydraulic cylinder bodies, high-pressure valve bodies, robotic actuator arms, compressor crankshafts, heavy-duty bearing housings
- Medical Devices: Artificial joints, surgical instruments, dental implants, orthopedic implants, medical equipment, structural components
Squeeze Casting Process
Advantages and Disadvantages
|
Advantages |
Disadvantages |
| High-pressure solidification creates a dense, uniform structure with mechanical properties approaching those of forged parts. |
High investment cost for specialized hydraulic equipment and control systems. |
|
Effectively eliminates shrinkage and gas pores under pressure, achieving a product density of≥ 98%. |
Highly sensitive process parameters require precise control of pressure curves and temperature gradients. |
| Enables near-net-shape forming of complex structures with material utilization ≥ 90% and minimal machining allowance. |
Mold life is approximately 50,000-80,000 cycles under high pressure/temperature, leading to high replacement costs. |
|
Significant grain refinement improves product fatigue strength by over 50% compared to traditional casting. |
Economically viable only for high-volume production (typically >10,000 units/month); not suitable for small batches. |
| Fully controllable solidification process ensures consistent quality with a reject rate below 3%. |
Stringent requirements for raw material purity and the melting process necessitate supporting high-end equipment. |
|
Products can be further enhanced with T6 heat treatment to improve overall mechanical properties. |
High technical barriers require support from a dedicated team of process engineers. |
Centrifugal Casting
Process Principle
Centrifugal casting utilizes high-speed rotating metal or sand molds to generate a strong centrifugal force, which evenly distributes the molten metal on the inner wall of the mold during the rotation process.
By precisely controlling the rotational speed, pouring temperature, and cooling rate, metal directional solidification is achieved, resulting in dense and defect-free cylindrical-shaped castings.
Application Fields
- Piping Systems: Petroleum pipelines, high-pressure water pipes, chemical process piping, municipal drainage pipes
- Machinery Manufacturing: Engine cylinder liners, large bearing sleeves, hydraulic cylinder barrels, industrial rollers
- Power Equipment: High-voltage cable conduits, electrical insulation bushings, transformer housings, switchgear sleeves
- Construction & Building Materials: Structural columns, road guardrail pipes, bridge support sleeves, architectural decorative tubes
Centrifugal Casting Process
Advantages and Disadvantages
|
Advantages |
Disadvantages |
|
Centrifugal force segregates impurities toward the inner surface, creating a high-purity, dense metal layer on the critical outer diameter. |
Severely limited to rotationally symmetrical shapes like cylinders, tubes, and rings; cannot produce complex geometries. |
| Forms precise internal bores without cores, significantly simplifying mold design and cost. |
Requires specialized centrifugal casting equipment, leading to high initial investment. |
|
Powerful centrifugal force ensures dense filling, effectively eliminating shrinkage porosity. |
Demands precise control of rotational speed and temperature, making process parameters highly sensitive. |
| Ideal for monolithic casting of large cylindrical parts, with single-piece lengths exceeding 12 meters. |
Mold preparation and preheating times are long, and changing over between different products is difficult. |
|
Material utilization exceeds 95% by eliminating traditional gating and riser systems. |
Equipment requires strict maintenance, resulting in relatively high ongoing operational costs. |
| Excellent surface quality on both inner and outer diameters minimizes machining allowance. |
It cannot produce structural parts with complex geometries, limiting its application scope. |
Lost Foam Casting
Process Principle
Lost foam casting uses expanded polystyrene (EPS) or copolymers to make the overall pattern, which is coated with a refractory coating on the surface of the pattern and then buried in dry sand for vibration compaction.
During pouring, the liquid metal vaporizes and decomposes the foam pattern, and its space is replaced by the liquid metal to obtain castings with the same shape as the pattern.
Application Fields
- Automotive Manufacturing: Engine blocks, transmission cases, intake manifolds, exhaust pipes, turbocharger housings
- Fluid Control: Multi-chamber pump bodies, valves with complex flow channels, hydraulic manifolds, pipe fittings, flanges
- Mechanical Equipment: Machine tool beds, equipment bases, gearbox housings, large brackets, structural frames
- Art Casting: Large sculptures, intricate decorative pieces, architectural art, crafts, monuments
Lost Foam Casting Process
Advantages and Disadvantages
|
Advantages |
Disadvantages |
| Eliminates traditional parting line constraints, enabling production of parts with complex curves, deep cavities, and irregular structures. |
Foam patterns require specialized molds for foaming, leading to high development and per-unit pattern costs. |
|
Enables integrated design of multiple components, reducing the number of molds and subsequent welding/assembly steps. |
Gases like styrene from foam decomposition require dedicated environmental treatment systems. |
| Dimensional accuracy is stable at CT8-9, with machining allowance reduced by 40-50% compared to traditional methods. |
Prone to carbon defects in the casting, which adversely affect mechanical properties. |
|
Achieves monolithic forming of complex internal structures, completely avoiding parting lines and flash issues. |
High process control complexity due to multiple parameters (e.g., foam decomposition, coating permeability). |
| Reduces machining requirements, increases material utilization to over 90%, offering significant cost advantages. |
Strict requirements for all production stages; process stability needs continuous monitoring and optimization. |
|
Ideal for large, complex parts, effectively supporting product lightweighting goals. |
Stringent requirements for foam, coating, and base sand quality make overall cost control challenging. |
Continuous Casting
Process Principle
Continuous casting is achieved by continuously injecting molten metal into a water-cooled crystallizer, forming a solidified shell layer on the inner wall of the crystallizer, and then continuously pulling out the billet through a billet pulling machine, realizing the continuous transformation process from liquid metal to solid billet.
The entire process is completed in a closed system, ensuring the uniformity and stability of the cast billet structure.
Application Fields
- Ferrous Metallurgy: Steel semi-products like billets for construction, slabs for automotive sheets, and round blooms for machinery.
- Non-Ferrous Metals: Non-ferrous shapes such as aluminum ingots for electrical uses, copper rods for cables, and zinc strips for galvanizing.
- Profile Manufacturing: Structural sections like I-beams for buildings, channel steel for equipment frames, and angle steel for connectors.
- Metal Products: Intermediate products including wire rods for steel ropes, tube rounds for seamless pipes, and strips for cold rolling.
Continuous Casting Process
Advantages and Disadvantages
|
Advantages |
Disadvantages |
| Enables genuine continuous production; single-strand annual capacity can exceed 500,000 tonnes. |
Limited product shapes, restricted to simple cross-sections like squares, rectangles, and circles. |
|
Uniform, dense strand structure with fine grains and significantly reduced segregation. |
Complex equipment systems; a single machine requires an investment of tens of millions of dollars. |
| Material utilization approaches 100%, eliminating waste from traditional gating/riser systems. |
Difficult process parameter adjustments; product size changes are time-consuming. |
|
Fully automated process control reduces staffing needs and manual labor intensity. |
Complex commissioning and operation demand support from experienced technical teams. |
| Stable, reliable product quality with minimal variation in mechanical properties. |
Limited service life of key components like molds leads to high maintenance and replacement costs. |
|
Reduces comprehensive energy consumption by ~30% compared to traditional ingot casting, offering significant cost benefits. |
Strand surfaces require cleaning/conditioning, and subsequent rolling processing is mandatory. |
Casting Process Selection Guide
Material Properties
Die casting is primarily suitable for non-ferrous metal alloys with melting points below 600℃, such as aluminum, zinc, and magnesium.
Sand casting, due to its high-temperature resistance, can handle high-melting-point ferrous metals, including various types of cast iron and cast steel.
Investment casting, with its unique process advantages, can meet the precision casting needs of special materials such as stainless steel and high-temperature alloys.
Order Volume
Die casting is designed for mass production and is suitable for production needs of over 100,000 pieces per year.
Permanent mold casting is suitable for medium-volume production scales of 10,000 to 100,000 pieces.
Sand casting is best suited for small-batch production of less than 100 pieces.
Investment casting is more suitable for small to medium-batch production of precision parts of several thousand to tens of thousands of pieces.
Structural Complexity
Investment casting can achieve ultra-thin wall thicknesses of 0.5mm and complex internal cavity structures, making it suitable for precision parts.
Lost foam casting breaks through traditional parting limitations and excels at deep cavities, irregular shapes, and complex multi-cavity structures.
Sand casting, through the combination of sand cores, can adapt to parts of medium complexity.
Die casting excels at manufacturing parts with complex shapes but relatively simple internal cavities.
Quality Requirements
Investment casting achieves precision levels of CT4-6 and surface roughness Ra1.6-3.2μm, suitable for high-precision applications.
Die casting exhibits excellent dimensional stability and precise tolerance control, while squeeze casting can achieve mechanical properties close to forgings.
Centrifugal casting ensures a dense, defect-free microstructure; each process has its strengths in quality aspects.
Overall Cost
While die casting molds are expensive, the unit cost is highly competitive in large-volume production.
Sand casting molds are simple, but subsequent machining is extensive, requiring careful cost calculation.
Investment casting has a high initial investment but significantly reduces subsequent machining steps.
The final decision must be based on a comprehensive trade-off based on the principle of optimal total cost.
Conclusion
Based on the above analysis of 13 major casting processes, each method demonstrates distinct technical advantages and optimal application fields.
Whether considering the versatility of sand casting, the precision of investment casting, the efficiency of die casting, or the specialized capabilities of centrifugal casting, selecting the appropriate process directly impacts product quality, production costs, and delivery timelines.
As a manufacturer specializing in aluminum alloy die casting and squeeze casting, CEX Casting leverages patented technologies and 29 years of industry expertise to consistently deliver high-quality castings and comprehensive technical support.
If you’re looking for a reliable partner for your next aluminum casting project, feel free to contact us for professional process selection advice and customized solutions.