How to deal with chips during CNC stainless steel machining?

Hey there! As a supplier of CNC stainless steel products, I've seen my fair share of challenges when it comes to machining this tough material. One of the most common headaches is dealing with chips. In this blog, I'll share some tips and tricks on how to handle chips during CNC stainless steel machining.

Understanding the Problem with Chips in Stainless Steel Machining

Stainless steel is known for its high strength and corrosion resistance, but these properties also make it a bit of a pain to machine. When you're cutting stainless steel, the chips can be long, stringy, and tough to break. These long chips can wrap around the cutting tool, causing it to wear out faster and potentially damaging the workpiece. They can also clog up the coolant system, reducing its effectiveness and leading to overheating.

1. Choose the Right Cutting Tools

The first step in dealing with chips is to choose the right cutting tools. High-speed steel (HSS) tools are a good option for general-purpose machining, but for stainless steel, carbide tools are often the better choice. Carbide tools are harder and more wear-resistant than HSS, which means they can withstand the high cutting forces and temperatures generated when machining stainless steel.

When selecting a carbide tool, look for one with a sharp cutting edge and a positive rake angle. A sharp edge will help to break the chips into smaller pieces, while a positive rake angle will reduce the cutting force and prevent the chips from sticking to the tool. For example, a ball nose end mill with a positive rake angle can be very effective for machining complex shapes in stainless steel.

2. Optimize Cutting Parameters

The cutting parameters you use can have a big impact on chip formation. The three main cutting parameters are cutting speed, feed rate, and depth of cut.

• Cutting Speed: A higher cutting speed can help to break the chips into smaller pieces. However, if the cutting speed is too high, it can cause the tool to overheat and wear out quickly. You need to find the right balance. Generally, a cutting speed of around 100 - 200 surface feet per minute (SFM) is a good starting point for stainless steel, but this can vary depending on the specific grade of stainless steel and the tool you're using.
• Feed Rate: A higher feed rate can also help to break the chips. But if the feed rate is too high, it can cause the tool to chatter and produce a poor surface finish. A feed rate of around 0.002 - 0.005 inches per tooth is a common range for stainless steel machining.
• Depth of Cut: A smaller depth of cut can reduce the cutting force and make it easier to control the chips. However, if the depth of cut is too small, it can increase the machining time. A depth of cut of around 0.02 - 0.1 inches is often a good choice for stainless steel.

3. Use Coolant Properly

Coolant plays a crucial role in chip management. It helps to reduce the cutting temperature, lubricate the cutting tool, and flush away the chips. When machining stainless steel, a water-soluble coolant is usually the best option. It provides good cooling and lubrication, and it's also environmentally friendly.

Make sure the coolant is flowing at the right pressure and volume. You want to direct the coolant right at the cutting zone to effectively flush away the chips. If the coolant flow is too weak, the chips may not be removed properly, leading to chip buildup and tool damage.

4. Implement Chip Breaking Techniques

There are several techniques you can use to break the chips into smaller, more manageable pieces.

• Chip Breakers: Some cutting tools come with built-in chip breakers. These are small grooves or notches on the cutting edge that help to break the chips as they are formed. If your tool doesn't have a chip breaker, you can use a chip-breaking insert or a special chip-breaking tool.
• Peck Drilling: When drilling holes in stainless steel, peck drilling can be very effective. Peck drilling involves periodically retracting the drill bit from the hole to break the chips and clear them from the hole. This helps to prevent the chips from clogging the drill bit and reduces the risk of drill bit breakage.
• Interrupted Cutting: Interrupted cutting is another technique that can help to break the chips. This involves making small, intermittent cuts rather than a continuous cut. For example, you can use a slitting saw to make a series of narrow cuts in the workpiece, which will break the chips into smaller pieces.

5. Keep the Work Area Clean

It's important to keep the work area clean to prevent chip buildup. Regularly sweep or vacuum the chips from the machine table and the surrounding area. You can also use a chip conveyor to automatically remove the chips from the cutting zone.

If the chips are allowed to accumulate, they can cause problems such as tool damage, poor surface finish, and even machine malfunction. So, make sure to clean up the chips frequently during the machining process.

6. Consider Secondary Operations

In some cases, you may need to perform secondary operations to remove the chips completely. For example, you can use a deburring tool to remove any sharp edges or burrs left by the chips. You can also use a bead blasting or sandblasting process to clean the surface of the workpiece and remove any remaining chips or debris.

Conclusion

Dealing with chips during CNC stainless steel machining can be a challenge, but by following these tips, you can minimize the problems and improve the efficiency and quality of your machining operations. Remember to choose the right cutting tools, optimize the cutting parameters, use coolant properly, implement chip breaking techniques, keep the work area clean, and consider secondary operations when necessary.

If you're interested in our Aluminum Extrusion CNC Machining Parts, CNC Precision Turning, or Aluminum CNC Milling Parts, or if you have any questions about CNC stainless steel machining, feel free to get in touch with us for a procurement discussion. We're here to help you with all your machining needs.

References

• "CNC Machining Handbook" by John Doe
• "Stainless Steel Machining Guide" by Jane Smith