Metal parts manufacturing plays a crucial role in almost all industries when manufacturing mechanical components. These components are crucial for ensuring that machines and tools operate as expected, and their demand continues to increase due to their durability and strength.
When it comes to manufacturing metal parts, making informed decisions about critical factors like material choice, process type, and the intended usage of the part is essential for achieving the desired results. Whether you’re producing parts for the automotive, aerospace, medical, or industrial sectors, these three factors influence everything from performance to cost-effectiveness and lead times.
Below, we explore these key considerations in detail and how each impacts the manufacturing process.
Material Choice
Choosing the right material is the foundation of any successful metal part manufacturing project. Each metal or alloy has distinct properties that can affect the strength, durability, weight, corrosion resistance, and cost of the part. Consider the following aspects when selecting a material:
Factors Influencing Material Choice:
Mechanical Properties:
The material must possess the right combination of hardness, tensile strength, and ductility required for the part. For example, stainless steel is chosen for its corrosion resistance and durability, while aluminum is favored for its lightweight properties.
Corrosion Resistance:
Depending on the environment in which the part will be used, it may need to resist corrosion. Parts used in marine, medical, or outdoor applications may require materials like stainless steel or anodized aluminum.
Cost-Effectiveness:
Some materials, such as titanium and certain high-performance alloys, may offer superior performance but come at a higher cost. Finding the right balance between cost and performance is key, especially for large-scale production runs.
Machinability:
The ease with which a material can be machined affects manufacturing time and overall costs. Metals like brass and aluminum are easier to machine, whereas harder materials like hardened steel or titanium may require more time and specialized tooling.
Commonly Used Materials for Metal Parts:
Steel:
Steel is an iron alloy that contains about 1% carbon. Not only is steel a high-strength metal; but it also offers a lot of flexibility since it can be machined, stamped, roll-formed, welded, and more. This makes steel a universal material for metal parts.
Stainless Steel:
Stainless steel has the advantages of steel plus the added benefit of corrosion resistance thanks to an increased amount of chromium – 10% or more by weight. Stainless steel parts are commonly seen in marine applications and in chemical plants.
Aluminum:
Since aluminum in element form is soft, it’s not ideal for mechanical purposes. That’s why it’s typically blended with other elements such as copper, magnesium, and zinc, then heat-treated to improve its properties. Automotive and aircraft parts are commonly made from aluminum.
Brass:
The highly versatile brass is an ideal choice when corrosion resistance is important. For example, many plumbing parts – like valves – are made of brass. It’s also incredibly strong and, depending on the ratio of brass used can fabricate everything from marine parts to coins.
Copper:
With its stringy structure, copper can be hard to machine. However, thanks to its electrical conductivity, copper is an extremely important metal for generating electricity and is often used in electrical wiring and tubing. Like other soft metals, it’s also commonly used as an element in many different metal alloys.
Process Type
Once the material is selected, the next crucial decision is choosing the appropriate manufacturing process. Different processes offer varying levels of precision, scalability, surface finish, and material compatibility. The choice of process should align with the material properties, part complexity, and production requirements.
Factors to Consider When Choosing a Process:
Part Geometry and Complexity:
For complex shapes and intricate details, processes like CNC machining or investment casting may be better suited. CNC machining allows for tight tolerances and is ideal for parts requiring precision.
Production Volume:
For low-volume production or prototyping, processes like CNC machining and 3D printing are more cost-effective and flexible. For high-volume production, methods like stamping, forging, or die casting can help reduce unit costs.
Tolerances and Surface Finish Requirements:
The precision needed for the part dictates the process. CNC machining is excellent for achieving high tolerances, while processes like forging may require secondary machining to meet tighter tolerances.
Lead Time and Flexibility:
Some processes are faster than others. For example, CNC machining has quick turnaround times, which makes it perfect for rapid prototyping or small batch production.
Common Metal Manufacturing Processes:
CNC Machining:
Highly accurate and versatile, suitable for both prototyping and production.
Casting:
Efficient for large volumes of complex shapes but may require post-processing for precision.
Forging:
Used for producing strong, high-stress parts but less flexible for intricate geometries.
Sheet Metal Fabrication: Ideal for creating parts like enclosures and panels, often used in automotive and industrial applications.
Know the Part’s Usage
Understanding the intended use and operating environment of the metal part is vital for determining its design, material, and production method. The specific performance requirements of the part should guide every other decision in the manufacturing process.
Key Usage Considerations:
Load and Stress:
If the part will endure heavy loads or stress, it needs to be made from a strong and durable material, and a manufacturing process must be selected that ensures optimal strength. For example, forged steel is often used for high-stress automotive parts like axles and crankshafts.
Temperature and Environmental Conditions: Will the part be exposed to extreme temperatures, moisture, or chemicals? High-temperature environments may require heat-resistant alloys, while parts exposed to chemicals or moisture may benefit from corrosion-resistant materials like stainless steel or aluminum.
Friction and Wear:
If the part will experience friction, such as in moving machinery, materials with wear-resistant properties like hardened steel or alloys with added coatings should be considered.
Precision Requirements: If the part is critical to the function of an assembly (e.g., in aerospace or medical devices), it must be manufactured with tight tolerances and surface finishes, requiring precise machining processes.
Applications to Consider:
Automotive Industry:
Parts like gears, axles, and brackets need to be durable, cost-effective, and often produced in high volumes. Steel is commonly used for its strength, but lightweight materials like aluminum are becoming more prevalent.
Aerospace:
Weight reduction is key, so materials like titanium and aluminum are favored. The parts also require high precision and must withstand extreme conditions.
Medical Devices:
Biocompatibility is critical, and materials such as stainless steel and titanium are used due to their ability to be sterilized and resist corrosion.
Conclusion
When manufacturing metal parts, understanding the interrelationship between material choice, process type, and the part’s intended use is essential for achieving optimal performance and efficiency. By carefully selecting the right materials, utilizing the best manufacturing processes, and considering the specific operational requirements of the part, manufacturers can ensure that the end product meets both technical and economic goals.