CNC milling, also known as computer numerical milling, is a machining process that uses rotating multi-point cutting tools and digital controls to gradually remove material from a workpiece to create a part or product specifically tailored to the customer's needs. This method can machine many materials, including metal, plastic, glass, and wood, and create several customers' design products and parts.
CNC machining services offer different functionality like chemical, thermal, mechanical,, and electrical processes. This article explains everything about CNC machining and why you need it.
The Meaning of CNC Milling
It is a computerized controlled product that uses a cutting to remove a portion of a workpiece. The workpiece is placed on the machine's table during the basic setup, and when the spindle rotates and moves, a cutting tool or tools are used to shape the workpiece into a final product.
The type and sophistication of the CNC milling machine determine the rotation and movement of the cutting tool. The method is quite versatile and works well with various materials, including glass, plastic, aluminum, and wood.
CNC-milled components have a high degree of tolerance because milling machines can achieve tolerances of +/- 0.001 in. to +/- 0.005 in. (Some machines can achieve a tolerance of +/- 0.0005 in.)
How CNC Milling Works?
The foundation of CNC machining is formed by CNC milling, CNC drilling,, and CNC turning. However, unlike others, it has a unique mechanism.
The procedure involves removing pieces from a workpiece using a spinning cylindrical cutting tool that is computer-controlled and operates along many axes.
What Are the Types of CNC Milling Operations
CNC has various operations with different applications and setups. These are some of the types of operations:
Form Milling
This is the best technique for creating irregular contours on a workpiece. The contour might be straight or straight with curves. The contour can be convex or concave and is created with teeth with the opposite. This means the form milling cutter should have a convex edge to produce a product with a concave edge. Form milling is quite slow due to the more complex cutting required to create curved surfaces.
Plain Milling
Plain milling is a knee and column operation used for flat horizontal surfaces. The workpiece lies parallel to the cutting tool, and as a result, the workpiece is sliced from one end to the other. The operator can feed the table vertically, crosswise, or longitudinally.
Face Milling
In face milling, the face milling cutter's rotating axis is parallel to the surface of the workpiece. The face milling cutter has a distinctive design because of its variable cutter inserts. It cuts with the help of its many cutting teeth. As a result, face-milled products have higher-quality surface finishing. Additionally, the procedure is tightly under control, making it simple to create the surface you want.
Angular Milling
Angular milling involves machining flat surfaces by bending a cutting tool at an angle. The process is similar to simple milling; the only difference is their angle arrangements. There are two kinds of angular milling cutters: single and double-angle cutters. The single-angle cutters work at angles of 450 or 600 and have teeth on the angular face and broad flat sides. The double angular milling cutters are preferable for cutting flat surfaces at 45°, 60°, and 90° because they have V-shaped teeth with conical surfaces.
What Are the Steps of the CNC Milling Process?
There are three steps in the CNC milling process, and they include:
Create a CAD model in 2D or 3D
Use CAM/CAD software like SolidWorks or Autodesk Inventor to prepare a machinable 2D or 3D final product drawing. Creating a CAD or CAM file for CNC machining depends on the type of software. While some software can convert a 2D image into a 3d CAD file, some software helps you trace the 2D image to convert it into a 3D file. You also have to give a technical drawing to the operator. The drawing should obtain the following:
● Construction lines
● Indication of threads
● Critical features/dimensions of a part
● Finishing preferences
● Tolerances
Convert Your Design to a CNC-Compatible File Format
The CNC milling machine won't understand your model, except if it's in a compatible format. Therefore, converting your CAD file into a CNC-compatible file format with CAM/CAD software is essential. STEP and STL are examples of such formats. However, if the software isn't working, you can opt for various online services like Convert.emachineshop.com and Cadexchanger.
After converting, the file will direct the machine on the cutting sequence, linear and rotational movement, toolpath, and machine workpiece speed.
Set Up a CNC Milling Machine Start Milling
The operator will place the workpiece on the table and attach the cutting tool to the spindle. They will then set up the CNC machine to load the machining program and start mining.
How to Choose the Right Material for CNC Milling?
Selecting a suitable material can be difficult because of the wide range of available materials. These are some factors to know the best material for your CNC milling:
Cost
The most essential factor influencing your choice is cost. But make sure you select the best material with the highest mechanical qualities within your budget.
Part Purpose
The ideal material must possess inherent properties that support its performance in the intended use. For instance, when it comes to corrosion resistance, stainless steel is superior to carbon steel.
Part’s Temperature
The material's melting point must be lower than the CNC milling machine's working temperature. This will minimize milling-related distortion.
Part’s Stress
Materials that are stable under stress must be used for stable parts under high stress. Failure to do so might result in deformation or cracking.
Dimensional Tolerance
It aids precision during milling. As a result, it becomes smooth to put these components together.
Advantages of CNC Milling in the Production Process
CNC milling is widely used in many industries because of its advantages. Some of these advantages include the following:
Quicker Assembly
Detaching the production capacity from the necessary staffing levels and reducing the human resources down the assembly line can increase the efficiency of manufacturing units. Manual assembly lines are more productive in high-production environments. When assembling the product it is so complicated that it requires specialized knowledge that machines cannot imitate.
Lower Production Costs
The use of CNC machines for milling helps to reduce the cost of production, and it improves the scalability and efficiency of assembly and production without wasting materials. Overall, it is one of the most comprehensive methods for reducing the cost of your business without compromising quality.
Disadvantages of CNC Milling in the Production Process
Anything that has advantages has its disadvantages. These are some of the disadvantages of the CNC milling production process:
Waste of Materials
The CNC milling process removes material to create the required part. As a result, there is much material waste compared to other production processes like 3D printing services.
High Maintenance Level
CNC millers need a lot of maintenance to stay in good shape. The machinery is expensive, and maintenance is, therefore, essential.
Factors Affecting the Cost of CNC milling
The cost of the CNC milling process depends on some factors, and they are:
Quantity Needed
When you outsource CNC milling services, it is less expensive to place larger orders because the cost per milled item is lower. They are founded according to the economics of scale, and the excellent repeatability of CNC milling speeds up manufacturing.
Material
Machinability, market cost, and availability are all important factors that affect the price of the material. The material is charged by block. There are two main types of CNC milling materials: metals and plastic. Plastic is highly available, machinable, and cheap. So they are cheap. Metals, on the other hand, are costly. Examples of metals are Stainless steel 304 ($90), Aluminum 7075 ($80), and Aluminum 6061 ($25) per block.
Part’s Complexity
A complex product design needs a machine that can efficiently mill the product. The higher the complexity of the design, the higher the complexity of the milling machine and the price.
Additionally, CNC milling services charge by the hour, and a complex design will need more time to complete its production. Companies that use CNC millers will see increased power usage from the equipment.
Get in Touch With Ares Prototyping Today For CNC Machining Services with Affordable Pricing
We specialize in producing high-tolerance precise metal and plastic parts at a reasonable price with our skilled CNC milling services. Thanks to our independently owned facilities' sophisticated multi-axis CNC milling equipment, you can supply high-quality products with a short lead time.
Our online quotation tool offers immediate quotations with an automated DfM report after you submit your CAD file and select your material and quantity preferences. The good part is you can even track your order and the process until delivery day.
