How to mill round parts with CNC machines step by step

You can make round parts with CNC machines. First, pick the right equipment. Next, hold the workpiece tightly. Set up everything carefully. Program the toolpaths for the machine. Then, start milling the part. Check the part after milling. Finish the part as needed. It is hard to hold round parts in place. Pay close attention to fixturing. Use V blocks to help hold the part. Use height gauges for better accuracy. Custom workholding can also help with cnc milling round parts.

Key Takeaways

• Pick the best CNC machine and cutting tools for your round part. CNC lathes work well for shapes that look the same all around. CNC milling machines are good for parts with tricky details.
• Use the right way to hold round parts tight. V blocks and 4-jaw chucks keep the part steady and help you cut it right.
• Mark your workpiece and make sure it is in the center before you start cutting. Use height gauges and coaxial indicators to line things up exactly.

CNC Milling Round Parts: Setup & Tools

Choosing Machines & Cutting Tools

You must pick the right CNC machine for your round part job. CNC lathes are best for shapes that are the same all around. CNC milling machines can also make round parts. They are good if you need to add special shapes or holes. The machine you pick changes how you hold the part. It also changes how many times you need to set up. Some machines make it easier to reach every side. If you use one setup for all steps, you get better results and save time.

Here is a table to help you compare machine types:

You also need to choose the right cutting tool material. The tool should match your part’s material and the type of cut. Here is a table of common cutting tool materials:

When you pick the material for your round part, think about how easy it is to cut. Aluminum is easy to work with and fits many jobs. Stainless steel is strong but harder to cut. Titanium is tough and light but very hard to machine. Plastics like ABS and Delrin are good for cnc milling round parts. They are easy to cut and shape.

Fixturing Techniques for Round Stock

It is hard to hold round stock tight when cnc milling round parts. You have a few ways to do this:

• V blocks help you hold round bars steady. Using two V blocks keeps things straight and stable. This lets you turn the part and mill more sides with good results.
• Vises are good for parts with flat or straight sides.
• Vacuum tables hold flat pieces in place.
• Modular fixture systems help with tricky shapes.
• Bore clamps hold the inside of round parts. They use a screw to open and center the part.

Tip: V blocks are great for holding rods and tubes. Be careful not to squeeze thin or soft parts too hard.

You can also use chuck kits. A 3-jaw chuck gives okay repeatability. A 4-jaw chuck lets you move each jaw for better accuracy. Here is a quick comparison:

Marking & Centering for Accuracy

Marking and centering are important before you start cutting. You want your part lined up with the machine. Use a height gauge to mark heights and find the center of holes. Height gauges also help you spot high and low spots on round parts.

Here are some common tools and ways to center round stock:

Note: Height gauge accuracy depends on the tool and how you use it. Temperature changes can change your measurements. Always check your setup before you start.

If you follow these setup steps, you will do better with cnc milling round parts. Picking the right machine, using good fixturing, and marking carefully all help you get the best results.

Programming & Milling Operations

Toolpath Setup for Round Features

You must set up toolpaths with care. Toolpaths tell the machine how to move the cutting tool. For round features, you can pick different strategies. Some toolpaths work well for simple circles. Others help you make curves or pockets that are more complex.

Here is a table with important things to think about when you program toolpaths for circular features:

Tip: Stepover changes how smooth your part will be. Small stepover makes the surface smoother but takes longer.

When you make pockets in round parts, you can use different ways. Here is a table of common pocket milling strategies:

You should watch for mistakes when you program. Common errors are using the wrong post processor, not zeroing the part, missing decimal points in feed rates, and using wrong command codes. Always check your program before you start.

Executing CNC Milling Round Parts

After you finish programming, you can begin milling. Pick the right spindle speed and feed rate for your material. For aluminum, here is a table with suggested settings:

You can use different cutting tools to finish round surfaces. Flycutters and end mills are popular choices. Here is a comparison:

Flycutters can make a mirror-like finish with gentle cuts. End mills do many jobs but may not make the same finish as flycutters.

If you want to keep your part steady while milling, you can leave tabs. Tabs hold the part in place but can cause stress and bending. Uneven force may make round parts warp. Try to balance your cutting force and take tabs off with care.

Here are some good milling strategies you can use:

• Adaptive Clearing: Removes lots of material by splitting the workpiece into Z-levels.
• Pocket Clearing: Cuts in steps from the center out.
• Circular Ramping: Moves the tool in a spiral to lower tool overload.
• Peck Milling: Cuts in small steps to control shaking.

Inspection & Finishing Methods

After milling, you need to check your part. Inspection makes sure your part matches the design. You can use calipers, micrometers, go/no-go gauges, height gauges, and video measuring machines (VMM). For tricky shapes, coordinate measuring machines (CMM) give exact and automatic measurements.

Here is a table of common inspection methods:

You should also check tolerances. Each tolerance band changes how much time and money you spend. Careful checks of form, direction, and position tolerances help you avoid mistakes.

Surface roughness is important for many round parts. You can measure roughness with a profile method, where an arm moves along the surface, or with a laser scanner. The profile method costs less unless you need very strict roughness control.

Finishing makes your part look and feel better. Here are some common finishing methods:

• Milling and turning shape and smooth the surface.
• Grinding gives tight tolerances and smooth finishes.
• Sanding uses rough paper or belts to make surfaces better.
• Bead blasting makes a matte or satin finish.
• Wet sanding uses water and sandpaper for a smooth surface, good for plastics.
• Tumbling smooths and removes sharp edges by rolling parts in a barrel.

You may need to deburr your part to take off sharp edges. Cryogenic deburring uses cold to make burrs break easily. Vibratory deburring machines use shaking to remove material. CNC devices can deburr tricky shapes with accuracy.

Note: Always check and finish your cnc milling round parts before you use them. Good inspection and finishing help you meet design needs and make better parts.

You can make round parts with CNC machines if you follow each step. Use strong fixturing so the part does not move. Always check your setup to make sure it is correct. Here are some tips: Keep the wall thickness more than 0.02 inches. Hold the part tight, but do not bend it. Look at every part to check the quality. Find more resources to learn new milling strategies and get better results.

FAQ

What is the best way to hold round parts for CNC milling?

You should use V blocks or a 4-jaw chuck. These tools keep your round part steady and help you get accurate cuts.

Tip: Always check that your part does not move before you start milling.

Can you mill round parts without a lathe?

Yes, you can use a CNC milling machine. You need strong fixturing and careful setup to get good results.

How do you find the center of a round part?

You can use a coaxial indicator or a probing tool. These tools help you line up your part with the machine for precise cuts.