Everything You Need to Know About CNC Milling

Welcome to the ultimate guide on CNC milling! This blog post covers everything about this precise manufacturing process, from the basics to advanced techniques.

Learn how CNC milling uses computer-controlled machines with rotary cutters to shape materials precisely, creating a wide range of components.

Discover different types of milling operations, the key components of CNC milling machines, and many more.

Let’s start!

What is CNC Milling?

Milling is a subtractive manufacturing process that uses a variety of rotary cutters to remove material from the workpiece, forming components with complex shapes and precise dimensions.

This process involves the movement of a cutting tool, usually mounted on a rotating spindle, over the surface of a block material to remove excess material and create the desired shape or dimensions.

It is one of many types of manufacturing processes available and can be used for everything from simple holes to complex contours in multiple-axis configurations.

CNC milling machines can produce efficient results quickly while maintaining consistent dimensional accuracy throughout production runs.

How Does CNC milling Work?

CNC milling involves using computer-controlled machines to cut materials based on programmed instructions in G-code precisely.

These machines calculate tool movements for precise cuts at various depths and angles. This method allows for exact replication of parts and offers advantages like automation and unparalleled accuracy compared to manual processing methods.

The CNC system utilizes various axes to maneuver the cutting tool with incredible precision, allowing for efficient material removal and replication of intricate designs.

Eight Common Types of Milling Operations

Common types of milling operations include face milling, plain milling, angular milling, form cutting, gear cutting, straddle milling, profile milling, and gang milling.

Let’s discuss those types further!

Face Milling

Face milling is a machining technique used to produce flat, level surfaces and slots on workpieces.

A face mill cutter consists of multiple teeth arranged in a circular cutting pattern around its body, enabling the user to cut more material than what would be possible with an end mill or side-milling cutter in one pass.

The face milling operation uses both vertical and horizontal machines to provide higher feed rates compared to other forms of cutting. This efficient process can quickly finish large tasks, making variable depth cuts when necessary.

The types of machine tools used for this operation depend on the material being milled as well as its size, shape, thickness, and desired surface finish.

For instance, larger parts are usually milled using horizontal CNC machines, while smaller components require the use of vertical mills.

Aside from these types of machinery, various cutters may also be utilized during face milling, such as shell end mills and staggered tooth end mills; specific configurations depending upon the application requirements outlined by each project.

Plain Milling

Plain milling is one of the most basic types of operations used in the CNC machining process. This type of milling uses effect cutters with various shapes and orientations suited to different needs and outcomes.

Generally, this type of operation uses horizontal spindles, which are rotated at high speeds to achieve optimal cutting behavior for a material.

By employing these specific tools, an operator can achieve highly precise results while preserving a great level of accuracy for even complex parts.

Common designs may involve angled grooves that require finely controlled movements from routers and drills used by CNC machines or those relying on drill bits to perform intricate geometric workpieces with significant precision levels.

Angular Milling

Angular milling uses angular cutting techniques to produce angled features on workpieces that may not be orthogonal to the tool axis.

During an angular milling operation, a disc cutting tool rotates on its axes at variable speeds. It feeds into the workpiece from different angles, allowing for unique shapes to be created quickly and accurately.

Angular milling can help create complex contours such as taper, especially when other operations are combined with it, such as drilling or tapping.

Compared to other types of machining processes, angular milling offers greater flexibility, particularly when creating 3D parts, since it allows for non-orthogonal machining contouring in all three axial directions.

Form Milling

Form milling is a machining operation involving using a specially shaped cutter to cut into and shape the materials on a workpiece.

Form milling is most often used in creating complex shapes and features, as well as for cutting keyways or grooves in components for accurate alignments.

This kind of machining is done with either horizontal or vertical machines, usually CNC-controlled, to ensure precision results.

When form milling, the cutter slowly rotates around its central axis while cutting through the material along its perimeter edge at predetermined angles; this allows both soft and hard materials, such as metals and plastics, to be formed into unique shapes.

Gear Cutting

This type of operation involves utilizing rotary cutters, such as form mills, face mills, and circular saws, to create precise shapes through contouring or cutting on a workpiece to produce parts with exact dimensions.

The main goal of CNC gear cutting operations is achieving tight tolerances - this means that the shape and size created must be extremely consistent across multiple pieces produced.

To do this effectively, different types of gear cutters are used that have specific characteristics suited for producing cleanly formed teeth on a desired pressure angle (usually 14.50).

These gear cutters can vary from 12 tooth count tools–those suitable for hobbing –and up to hundreds or even thousands of counts - useful for shaping complex tooth profiles like V-Shapes accurately with precision and repeatability.

Straddle Milling

This is an important CNC milling operation that allows a machine tool to work on two or more parallel workpieces with a single cut.

This process involves using two side-by-side milling cutters mounted on an arbor, which create parallel slots, grooves, or surfaces on the workpiece.

Straddle CNC milling typically uses straight-tooth cutters for processing, and it can efficiently machine multiple workpieces simultaneously.

Applications of straddle mille range from creating grooves on shafts and ribs for mounting wheels comfortably to manufacturing components with high precision measurements quickly; producing parts in bulk amounts becomes much easier thanks to this efficient and reliable operation.

Profile Milling

There are four main types of profile milling: roughing, semi-finishing, finishing, and super-finishing.

It involves operations that involve simple geometric features like hole-making and pocket-milling.

Round inserts and concepts with radius are also used in this type of profile milling since they allow for efficient cutting when producing parts with certain geometric intricacies.

Profile milling processes provide quality parts made up of intersected planes such as zones or cavities that can turn complex aesthetic forms into reality while making sure the final products have precise dimensions and uniformity even on materials hard to machine, such as stainless steel, titanium, and inconel alloys.

Gang Milling

Gang milling is a subcategory of form milling that involves using two or more cutters on the same machine arbor with varying sizes, shapes, or widths. This process can create complex patterns and shapes by allowing for multiple cuts at once.

As an advanced form of CNC machining, gang milling offers increased accuracy and efficiency compared to traditional methods as it cuts into materials faster with higher precision.

With this method, engineers can craft intricate parts much simpler than ever before, as well as reduce fabrication time significantly without compromising quality.

The Main Components of CNC Milling Machine

A CNC milling machine is composed of several essential components that enable it to cut and shape a workpiece according to a set program.

Here they are:

Machine Interface

The machine interface serves as the main link between the operator and the machine.

It provides operators with a platform to input data, monitor the progress of their product while it is being machined, and make adjustments if needed.

The control panel includes various knobs, switches, and buttons that enable users to accurately operate CNC equipment while also keeping track of any changes that might be necessary during production.

Column

The column houses many important components. It is a vertical structure connected to the base that moves along an axis and holds both the tool turret and oil housing.

This connection allows for precise adjustments when cutting or turning materials with minimal variation or movement from its starting point.

Additionally, by connecting to the base structure, it provides stability while the motorized spindle rotates to create complex shapes accurately according to programmed instructions.

Knee

The knee enables adaptation to changing conditions and automated movement. It works in conjunction with the column, power feed mechanism, work table, and spindle to ensure accurate alignment of tools during cutting operations.

This critical piece of machinery adjusts its position based on the G-code supplied to the CNC controller, which helps create uniform results across all product runs.

Saddle

The saddle assists with both accuracy and stability. Located under the worktable, this component uses its parallel movement to support workpieces during machining.

This allows for precision cuts and eye-catching details that would not be possible without the stable backing of a sturdy saddle.

Worktable

The worktable is made of cast iron, and it features T-slots that allow secure attachment of the workpiece so that it can be separately positioned or rotated in relation to cutting tools.

This rigidly mounted table facilitates movement and rotation for multiple machining profiles.

With its precise construction and ability to firmly hold the workpiece during operating cycles, a reliable CNC machine tool worktable is crucial for high-performance results.

Spindle

The spindle holds and drives the cutting tools used during milling operations. It controls both the RPM and feed rate in CNC milling.

Additionally, when the lock is set at a given position, it becomes responsible for positioning the Z-axis, allowing up or down movement required to manipulate shapes designed by engineers.

For the proper functioning of a CNC machine, components like pillars are also significant aspects that support the spindle from tipping due to its weight forces during rotation, as well as improving accuracy while working with materials using higher torque settings on spindles.

Arbor

An arbor, also known as a spindle, holds and secures the cutting tool in place during machining operations.

The size and design of an arbor will vary depending on the type of milling operation being performed.

Rigidity should also be considered to eliminate movement during torque loads from cutting forces, which could lead to inaccurate cuts or damage your parts and tools in extreme cases.

By providing support and stability at various angles, constructing a stable spindle can reduce vibration while increasing smoothness and accuracy throughout processing time—all factors critical for successful production with CNC milling machines.

Ram

The ram is located at the top of the column. It is an adjustable arm-shaped piece that can be moved up or down to position properly for whatever job needs to be done.

It holds the milling head—a rotating tool used to cut away material from a workpiece—in place. It allows it to move in all directions as needed, making precise calculations and movements possible through computer numerical control (CNC).

Machine tool

The machine tool most commonly consists of a spindle, which holds and rotates the cutting tools used to remove material from the workpiece, and a work surface or holding device onto or into which the workpiece is placed.

The ability of different types of machine tools to articulate in various directions enables them to perform complex cutting patterns with accuracy and precision.

For instance, some can be articulated vertically as well as horizontally, allowing them to create more angles for deeper cuts that are not possible by traditional manual woodworking methods.

Conclusion

CNC milling is a precise manufacturing process using computer-controlled machines to cut materials with accuracy.

It offers versatility through various milling operations like face, plain, angular, form, gear, straddle, profile, and gang milling.

DEK's CNC milling services optimize precision engineering, utilizing advanced machinery and quality control measures for cost-effective and intricate component production.

Contact DEK anytime!

Frequently Asked Questions

Is CNC machining the same as milling?

No, CNC machining is not exactly the same as milling. While they are related processes in that they both involve removing material from a workpiece with cutting tools, there are important distinctions between them.

CNC milling is a specific subset of CNC machining that involves using rotary cutting tools to remove material and create detailed or precise components.

CNC milling focuses on rotary cutters working along the surface of a material to achieve the desired end product, which is particularly useful for intricate features or textures without relying on chemical finishing methods such as sandblasting or plating.

What are common uses for CNC milling?

CNC milling is widely used in aerospace and medical fields for intricate parts, metalworking, prototyping, and automotive manufacturing, among others.

Even in crafting items like instruments or furniture, CNC milling ensures accurate shapes.

For instance, in medicine, it crafts implants with precision for safe insertion.

In aerospace, it guarantees safety and lightweight parts that other methods can't match.

CNC Milling vs CNC Turning, which is better for you?

CNC milling is ideal for intricate shapes and detailed curves due to its ability to handle complex, three-dimensional surfaces efficiently, using multiple axes of movement. It's recommended when precise shaping is crucial and generates less waste than manual processing.

On the other hand, CNC turning is suitable for simpler parts like circles or cylinders, often requiring fewer tools, particularly for designs with curved edges or milled grooves/depths.

Is CNC milling expensive?

CNC milling costs fluctuate based on machine size, complexity, and precision needs.

Machines range from a few thousand dollars (for hobby models) to hundreds of thousands for industrial-grade ones, with maintenance costs scaling similarly.

Additional factors like machine type, skilled labor, and intricate manufacturing processes can elevate expenses.

Hourly rates span $10-$150, but businesses can implement strategies to trim these costs when integrating CNC machining into their operations.

What are 3-, 4- and 5-axis milling machines?

3-axis milling moves along X, Y, and Z planes for cutting and shaping.

4-axis milling adds rotation of the cutting tool around its own axis (A axis) for more precision in reaching various points in space.

5-axis milling incorporates 3+2 index CNC milling and continuous CNC milling, allowing simultaneous rotation of both workpiece and spindle. This offers extremely precise results over complex surfaces by employing two rotational axes alongside the three linear ones, ideal for intricate designs and curved shapes along multiple planes.

What are the benefits of CNC Milling?

CNC milling is way better than manual machining because it's super precise and accurate.

Computers control the tools, so the parts come out exactly like the design plans, which saves a lot of materials and money by reducing mistakes.

Plus, it's awesome for big production runs because it's faster and more consistent than old-school methods, and it saves on labor costs, too.

What Industries will need CNC Milling?

Industries such as aerospace, medical, engineering, automotive, and more heavily rely on CNC milling for precision manufacturing.

It's crucial for creating intricate parts in aerospace (like turbine blades), ensuring accuracy in medical equipment, and prototyping in various industrial sectors for metal or plastic products.

How do you get the most out of CNC milling with DEK?

DEK's CNC milling services offer an innovative solution to complex components and material removal needs.

Combining advanced machinery with expertise in machining processes, DEK delivers clients cost-effective production outcomes that realize intricate designs within specific parameters.

To maximize the benefits of such precision engineering while remaining on budget, engineers should utilize a series of strategies:

• Using advanced CAD/CAM software enables engineers to generate 3D models and generate real-time feedback
• Strategically selecting the proper cutting tools for each part according to size and design specifications contributes significantly by minimizing dross or defective parts
• Integrating quality control measures into product manufacturing cycles not only ensures optimum performance but validates well created products produced within tight tolerances.

Ultimately, these are just a few steps toward optimizing CNC milling projects with DEK.

DEK provides seamless support every step of the way, from planning out projects optimally to verifying quality assurance beyond expectations.