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A common practice in CNC part manufacturing is to reduce the chance of damage or injury caused by sharp corners of the part. To fix this, mechanics removed part of the 90-degree angle, creating a chamfer, also known as a bevel. Although the terms "bevel" and "chamfer" tend to be interchangeable in practice, there is a distinct difference between the two. Let's take a moment to examine the difference between bevels and chamfers and see how CNC machining uses these features when making parts.

Define the difference between a chamfer and a chamfer

The terms "bevel" and "chamfer" describe the same geometric feature in a part, but with differences, and defining them in detail helps to discern the difference:

Bevel

A bevel is a sloping edge between the two major faces of a part to facilitate connection to another face. Bevels can be measured at any angle other than 45 degrees, and they help improve wear resistance, safety and aesthetics. For example, bevels are present in the blades of cutting tools, mirrors and glass furniture to prevent injury from the sharp edges of the glass.

Chamfer

Unlike the hypotenuse that connects one part to another, a chamfer transitions between two right-angled surfaces of the same part. Unlike bevels, chamfers are always at a 45-degree angle. Chamfering removes sharp edges at 90-degree angles of parts to prevent injury during handling. Chamfering also protects the corners of the part from damage, improving the overall integrity of the part.

Operators use chamfer mills or "tools" when milling a part to create a bevel or chamfer in the machined part. Bevels may require more passes to complete and usually cut more area than chamfers, but this is subjective. In addition, double-chamfer end mills can cut bevels on the top and bottom of the workpiece without flipping the workpiece. Machine shops find these tools versatile as they can be used for chamfering, chamfering, deburring, speckling and countersinking. However, bevels and chamfers add to the manufacturing cost of the part, discussed below.

Example of left bevel and right chamfer.

The cost of adding extra functionality to the design

It's easy to see why bevels and chamfers are used to protect parts and their users. However, these features are often more for aesthetics than function, and they add to the production cost of the part.

Some practical questions to ask before including a bevel or chamfer in your design:

Does the part require bevels or chamfers to function?

Is a bevel required for safety purposes?

How to check the tolerance of bevel or chamfer?

Is this a cost-effective feature to add to the design?

Features such as bevels and chamfers require additional time in the manufacturing process. Even a 5% increase in time per part adds up to a considerable cost increase when multiplied by the number of parts produced. If unrelated functions don't have any necessary function or purpose, reconsider them. The specified tolerances for bevels or chamfers should also undergo some scrutiny. Machine shops need more time to manufacture and inspect tighter tolerances, which also increases the expense of part production.

Money-saving countersinks and other chamfering features

While the aesthetic uses of chamfers should be carefully examined to avoid unnecessary manufacturing costs, there are some cost-effective chamfer applications. For example, countersinking threaded holes helps avoid burrs during the tapping process that can affect how the two mating surfaces hold together.

Countersinks also help the bolts align correctly at the outset and avoid costly cross-threading during assembly. For some holes, such as aircraft rivets, accurate countersinks are so important that they require tight tolerances to ensure a sufficient amount of mating material available for a secure connection.

Another cost-effective use of chamfering is on the internal features of milled parts. Designing the chamfer into the feature of the part rather than grinding the corner flat will reduce the cost of manufacturing the part. Chamfering will reduce the time it takes to cut right angles in a part and allow the use of cheaper tools. Internal chamfers also help prevent dust and waste from accumulating in the corners of the part.

Considering all of these issues before designing a bevel or chamfer into a part offers advantages. If the design does not require these features, excluding them will simplify manufacturing, saving time and money. On the other hand, if the design does require them, the impact on production time and expense can still be reduced. One approach is to provide large tolerances, simplifying the manufacture of bevels and chamfers if exact dimensions are not critical. Another option is to completely remove the chamfer feature from the CAD model and add a note on the 2D drawing instructing the machine shop to "remove all sharp edges".

Shenzhen Xiehe Company is mainly engaged in the production and manufacture of non-standard precision hardware parts. It has been deeply involved in the industry for many years and has rich experience. If you have requirements for CNC lathe machining, five-axis machining services including aluminum, copper, stainless steel, iron, titanium alloys, plastics and other products, you can contact Xiehe, and we will provide you with a low-cost and high-quality integrated solution .