Types of Chips Formed During CNC Milling

CNC Milling is a crucial aspect of CNC machining services and plays an essential role in crafting high-quality components for a variety of industries. Understanding how chips formed during CNC milling is crucial for businesses seeking CNC machined parts, as well as CNC operators crafting the pieces. As CNC milling is both an art and a science, understanding how CNC milling chips affect the final product allows for a practical assessment of the correct method and materials for designing and fabricating the best components with minimal waste.

The Complex World of CNC Chips

With its combination of material science and cutting mechanics, CNC milling can create complex, non-rotating and rhomboid parts that adhere to tight specifications and the highest quality controls. The high-velocity milling process offers customized and intricate shaping of a variety of materials, and as the milling process takes shape, excess material is removed. This extra material, referred to as ‘chips’ varies depending on the material being used, cutting method, and overall construction of the component.
The classification of CNC milling chips falls into the following categories:

1. Discontinuous Chips

Discontinuous chips are identified by their non-uniform shape, which results from repeated fracturing or breaking apart. These chips often form when machining metals such as cast iron, brass, and bronze. Various factors like low feed rate, high cutting speed, and deep cuts can lead to these chips. These chips provide an excellent finish and output rate on hard or brittle materials, but produce inferior results for ductile materials while increasing machining time.

2. Continuous Chips

Long, bonded, and uniform coils are a unique characteristic of continuous chips. High cutting speeds and low friction are some factors that contribute to their formation when machining compatible metals like aluminum and mild steel. Continuous chips offer a cleaner surface finish, longer tool life, and a highly efficient CNC milling output. However, continuous chips may present challenges in removal, often requiring chip breakers.

3. Continuous Chips with Built-Up Edges

These chips have similar properties to continuous chips but differ in smoothness. High friction, usually created by high CNC milling temperatures and speeds often lead to their formation. These chips can stick to the edges of the tool, creating built-up edges that change size during cutting,

4. Non-Homogenous Chips

Also called serrated or heterogeneous chips, non-homogeneous chips have a semi-continuous structure. They resemble a saw tooth, generally forming in materials with low thermal conductivity, like titanium alloys and austenitic stainless steel. Several factors contribute to their formation, such as the strain at medium cutting speeds, as well as the material’s low thermal conductivity and subsequent thermal softening.

The Necessity of Chips Breakers

Chips normally break off against the tool or workpiece, but the bonded nature of continuous chips can create a tangled mess of chips called birdnesting. Birdnests can wrap themselves around tool parts and cause significant damage or may rapidly fill machine hoppers. Both situations require manual clearing, which increases machine downtime and increases health and safety risks for operators. Adding the proper chip breaker can eliminate both of these problems as it cuts the continuous chips into a more manageable size.

CNC Chip Control

CNC milling is about more than fancy machines and complex outputs. It is a complex combination of physics, engineering, and material science. By understanding the CNC chip formation likely to occur during machining, the design and production process can be sped up. In addition, using chip formation as a real-time diagnostic feedback tool reduces machine stress and downtime.

Accurate Machine Tool controls for CNC milling chip variables, providing you with reliable machine efficiency, precision tolerances, and the highest level of product quality. As a trusted partner in CNC machining and milling, our wide array of services can help you through your next project. For expert assistance, contact Accurate Machine Tool today.