CNC machining material selection
Stainless steel is an excellent CNC machining material choice for making strong and durable items. Here are some reasons to choose stainless steel for your CNC machining projects.
High Tensile Strength
stainless steel machining part has a higher tensile strength than mild steel, brass, and different types of aluminum alloys. Tensile strength refers to the amount of tension required to stretch a material to its breaking point. This is especially important for many products that have many bending and rolling parts during their service life.
Low-Temperature Resistance
Some stainless steel grades maintain their stability at a variety of temperatures. For example, austenitic stainless steel performs well in sub-zero temperatures, with excellent toughness and improved tensile strength. However, it is worth noting that not all stainless steel grades have this property.
Corrosion Resistance
Stainless steel has excellent corrosion resistance and can resist scale and rust. This corrosion resistance makes stainless steel an ideal choice for a variety of indoor and outdoor applications, including extreme temperatures and pressures. The reason stainless steel has this property is that the metal contains chromium, which forms a thin barrier when it comes into contact with oxygen.
Appearance
Stainless steel has a silvery-white appearance that will not discolor or rust over time. Its appearance is due to the high content of chromium. Furthermore, stainless steel has other properties besides strength. Due to its aesthetic appearance, CNC-machined stainless steel parts have a clean, modern look.
Challenges of Custom Stainless Steel Machined Parts
Stainless steel alloys are somewhere between titanium and aluminum in terms of hardness, machinability, strength, and temperature resistance, but there are some challenges involved. Here are some of the challenges involved in machining custom stainless steel parts.
Overheating
Unlike many other types of steel and metals, stainless steel is a poor thermal conductor. But machining with stainless steel causes it to heat up quickly, which can damage the stainless steel itself as well as the tools and CNC machines used in the machining process.
Difficulty in Surface Finishing
Choosing the proper surface finish for stainless steel CNC machined parts is difficult in determining its aesthetics and other properties such as corrosion resistance, electrical conductivity, impact resistance, and weldability.
Technical Requirements
Processing stainless steel requires technical skills and considerations. Since machining stainless steel is tricky, using the wrong cutting tool or speed can damage the material. This challenge makes machining stainless steel very time-consuming and slow.
Poor Machinability
Stainless steel is more difficult to machine than other metals. Furthermore, it hardens very quickly and is difficult to control, which results in poor machinability. Therefore, machining stainless steel requires specialized tools.
Quick Tips for CNC Machining Stainless Steel
There are some challenges with CNC machining stainless steel, but there are ways to avoid these issues and ensure smooth machining. Here are some quick tips for CNC machining this metal.
Choose Special Milling Tools and Drills
It is best to use high-speed steel milling tools and drills made of molybdenum or tungsten. They can withstand the stress of the process and wear less when cutting stainless steel. These tools also improve surface finish. Avoid tools that wear easily as this may reduce machining speeds while increasing production costs.
Manage the Heat Generated
One of the reasons why stainless steel CNC machining fails is heat. Keeping cutting speeds low and using coolants to manage heat is the best option. Also, it is usually recommended to stop the machining when the material starts to overheat.
Use Interpolation and Chip Breaking Cycles
Using interpolation and chip-breaking cycles to manage chip formation during cutting is one way to manage chip formation. Doing so helps eliminate long, elongated chips. Check the tools regularly as worn cutting tools form more chips.
Protecting Workpieces from Deformation
Many factors can cause workpiece deformation, including speed and feed rates, as well as the cutting tool. Using worn cutting tools can increase tool deflection, causing the part to be out of tolerance and deform. This is why it is important to use the recommended speeds and feed rates when machining stainless steel.