Computer numerical control—i.e., CNC—machining is a subtractive manufacturing process used to produce high-precision parts and components designed and built to tight tolerances. By employing computerized machines and tooling, industry professionals use the method to process a wide range of materials, each of which offers its own manufacturing benefits and limitations.
The following blog post serves as a guide outlining what factors to consider when choosing a material for a CNC machining project. Additionally, it compares some of the materials commonly used and their characteristics and typical applications.
How to Select the Right CNC Material
The material used in a CNC machining operation can affect both the quality and performance of the finished part. When choosing a material, there are several factors to consider. The answers to the following basic questions can aid in the selection process:
What mechanical, thermal, and other material properties are necessary for the product to perform adequately in the application and operating environment?
Which available materials fulfill all or most of the necessary characteristics to meet design requirements?
Which material allows for the highest level of performance, the best machinability characteristics, and the most cost-effective production?
However, answering these questions requires a thorough understanding of product requirements and the characteristics and common applications of each potential material.
Comparing Different CNC Materials: Material Properties and Common Applications
Industry professionals employ a wide range of materials in CNC machining operations to suit different product and project specifications. Some of the most commonly used materials include:
One of the most common and easy to machine metals available, aluminum is a highly versatile and cost-effective option for CNC machining projects. Additional material properties include:
Medium strength (6061) and high strength (7075)
Corrosion and temperature resistance
Thermal and electrical conductivity
Typical applications include:
for 6061: aircraft and marine fittings, camera lens mounts, couplings, and electronic hardware
for 7075: aircraft and bike parts, gears and shafts, fuse parts, keys, missile parts, and valves
Similar to aluminum, brass is easy to work with and cost-effective. Other material properties include:
Typical CNC machined parts include:
Electronic hardware and contacts
Bronze consists of copper and zinc and carries many of the same physical and mechanical properties of the base copper material, such as:
Thermal and electrical conductivity
Typical products produced include:
Bearings and bushings
. Cast Iron
In CNC machining operations, cast iron is primarily used for its ready availability, strength, and wear resistance. Typical applications include:
Car and truck parts
Wind generation equipment parts
Oil well pump components
Tools and machine tool frames
Copper offers several characteristics that make it suitable for CNC machined parts, including:
Some of the CNC machined products typically made from copper include:
Automotive and general engineering parts
. Nickel and Nickel Alloys
There are a variety of nickel and nickel alloys, such as Hastelloy and Inconel, available for use in CNC machining operations, each of which offers:
Medium to high strength
Corrosion and oxidation resistance
Typical applications for these materials include:
for Hastelloy: chemical reactors, distillation equipment, pipes and valves, and pressure vessels
for Inconel: automotive and aerospace parts, consumer electronics, and healthcare devices
. Steel and Steel Alloys
Steel is available in a wide range of grades to suit different industrial and commercial machining projects. In general, each alloy demonstrates the following properties:
High strength and hardness
Low corrosion resistance
High formability, machinability, and weldability
Applications of steel in CNC machining operations include:
. Stainless Steel
Stainless steel combines the strength and hardness of steel with greater corrosion resistance. In addition to these advantageous characteristics, it also offers good machinability and weldability.
Industrial and consumer applications include:
Aerospace and automotive parts
Food processing equipment
Medical and surgical instruments
. Variety of Plastics
Plastics serve as a low-cost, easy-to-machine alternative to metals for applications where strength and electrical conductivity are not critical. Depending on the specific plastic formulations, some of the properties that plastic demonstrate are:
Nylon: fair flame resistance and insulation
PVC: excellent chemical and corrosion resistance and good flame resistance
PEEK: high stability and strength, impact resistance, and minimum creep
Typical applications include:
for nylon: bearings and insulators
for PVC: construction profiles to medical devices, roofing membranes to credit cards, and toys to pipes
for PEEK: connectors, switches, and test sockets
CNC Materials From Technox Machine and Manufacturing, Inc.
For CNC machining operations, industry professionals most commonly employ aluminum, steel, and stainless steel due to their overall strength and versatility. However, depending on the part and project specifications, they may also utilize other materials for enhanced thermal and electrical conductivity, rust and corrosion resistance, or other required material properties.
At Technox Machine and Manufacturing, Inc., we have a broad range of materials available to suit a variety of machining applications. Our team has the knowledge and expertise to help you select the material with the right characteristics for the cost-effective production of your components. Contact us for more information about our material availability and capabilities or request a quote to discuss the details of your next project.
Computer Numerical Control (CNC) machining is a high precision method for manufacturing customized parts derived from a variety of different materials and within very tight tolerances. There are many benefits that come from implementing a CNC machining production solution.
Understanding CNC Machining
CNC machining is considered a subtractive manufacturing technology, which means that the end product is formed by selectively removing excess material from the workpiece. Every end-to-end CNC machining operation follows a similar four-step production process.
These four production phases are:
Parts produced via CNC machining generally start out as initial designs from Computer Aided Design (CAD) software. In the design phase, engineers give careful thought to all aspects of the desired final product, such as parameters for optimal performance, operating conditions for the end part, and acceptable tolerance variation levels.
Upon completion of the initial design phase, the CAD model must be converted into a functional CNC program using Computer Aided Manufacturing (CAM) software. CAM software is able to extract the geometrical requirements from the CAD model’s origin file and translate them into a CNC-compatible programming language—such as G-code or M-code—which will dictate the mechanical operations of the machine.
CNC Machine Preparation
Next, the CNC machine operator must set up both the machine and the target material according to the specifications required by the CNC program. The operator will ensure that the correct cutting or drilling tools are properly installed and are matched with the appropriate bits or end mills. The operator must also set up the workpiece, typically either in a stationary clamp or attached directly to the CNC machine.
Executing Programmed Operations
Finally, the CNC machine operator executes the desired mechanical processes. During operation, the CNC program precisely controls the movements of the machine tooling.
Types of CNC Machines
The most common types of CNC machines are those that use cutting tools to remove excess material from the workpiece. While there are CNC machines that employ water jet cutting and electrical discharge machining (EDM) operations, this guide will focus on the five most common categories in the following list, divided into two basic classifications: 3-axis and multi-axis machines.
3-Axis CNC Machines
3-axis machines allow cutting tools to move along straight three-dimensional vectors (up and down, left and right, forward and backward). There are two types of 3-axis CNC machines:
CNC Milling Machines
In CNC milling operations, the workpiece remains stationary and a high-speed rotating cutting tool comes down onto the workpiece to remove excess material. This type of machine is very useful for forming basic geometric shapes.
In CNC turning operations, the cutting tool remains stationary while the workpiece rotates at a high speed on a spindle. CNC turning offers the ability to produce cylindrical parts quickly and with tight tolerances. For example, Technox Machine and Manufacturing has CNC lathes that can produce parts with dimensions of up to 152″ in diameter and 240″ in length, while still holding tight ± 0.001″ tolerances. The big disadvantage to 3-axis turning operations is that only cylindrical parts can be manufactured efficiently.
Multi-axis CNC machines are similar to 3-axis machines, but with a higher degree of freedom in mechanical movements. For instance, multi-axis machines can employ rotational and diagonal cutting operations. There are three main types of multi-axis CNC machines:
Indexed 5-axis CNC Milling Machines
Even though this type of milling machine can only cut along 3 linear axes during operation, in between operations the operator has the ability to rotate the bed and tool-head for the next cut, allowing for increased shaping capabilities.
Continuous 5-axis CNC Milling Machines
This machine type allows for continuous movement along the three linear axes and two rotational axes during operation. This gives the operator the ability to create highly complex forms from the target workpiece.
Mill-Turning CNC Centers
Mill-turning centers combine the functionalities of CNC lathes and CNC milling machines. The workpiece may be rotated at high speeds on a spindle or precisely positioned for milling operations.
Designing CNC Machined Parts – CAD Model Design
A 2D vector or 3D solid part CAD design is the point of conception for a CNC machined-part. Besides design requirements directly related to the product’s end application, engineers must also be mindful of the capabilities and limitations of the CNC machine that will be utilized for the actual cutting operations.
The engineer must convert the CAD model’s origin file into a CNC-compatible format, such as the open-source STEP or IGES format, or a more restricted format like IPT or SAT. It is also considered a best practice for an engineer to create a technical drawing that will be sent along with the digital CAD instructions. These drawings are used to verify design tolerances and geometries; help the machinist to identify the part’s salient features; and serve as a tangible source of verification should questions arise.
Benefits of CNC Machining
CNC machining offers several competitive advantages, including:
Quick order lead times
Creates products with exceptional physical properties and performance thresholds
Appropriate material selection is critical for CNC machining operations. This choice is largely dependent on the expected usage for the end product. You’ll need to examine a range of material properties to determine which is best for your design, such as:
Ease of operation
At Technox, we utilize a broad spectrum of materials for our machining operations, including:
CNC Machining Applications
CNC machined parts are employed in a vast array of applications across industries. At Technox, we serve a broad range of sectors, including:
Food and beverage
Oil and gas
CNC Machined Parts at Technox
At Technox Machine and Manufacturing, we offer versatile, customized solutions to our clients and we deliver only the highest quality work. Our machining capabilities include:
Computer Numerical Control (CNC) technology has dominated the metal forming industry in recent years, as it offers advanced precision and repeatability that can be impossible to achieve with manual processes alone. With so many CNC technologies on the market, it can be difficult to distinguish between them and what they are used for. While there are many similarities between CNC milling and turning, there are also distinct, important differences.
Understanding the Differences Between CNC Milling and Turning
While CNC milling is nearly synonymous with CNC machining, CNC turning often produces parts faster and more affordably than milling. CNC milling is limited to the range of motion of the cutting tools. CNC turning is not as good at conserving material but allows for complex design options and faster operations.
(Click on image to enlarge)
CNC milling is a machine process which produces custom-designed parts or components by progressively removing material from the workpiece using rotating multi-point cutting tools and computerized controls. These systems usually have three linear degrees of freedom. They can move freely around the X, Y, and Z axes while the workpiece remains stationary. This limited dimensional operation reduces the speed of operations, making milling more suitable for prototyping and smaller production runs.
CNC turning is a manufacturing process that involves holding bars of material in a chuck and rotating them while feeding a tool to the piece to remove material until the desired shape is achieved. As the desired shape is achieved through the removal of material, it is also known as subtraction machining.
All of the work can be completed from one side if the CNC turning center has only one turret, but some turning centers have a main spindle and sub-spindle for even faster operation. With this configuration, the main spindle partially machines the workpiece, which is then moved to the sub-spindle to complete the job on the other side of the part. The speed of CNC turning operations makes it an ideal process for large production runs with short lead times.
CNC Milling and Turning: Applications and Types of Materials
The production capabilities of CNC milling include a range of processes, such as:
CNC mills provide superior material conservation efficiency, which leads to a reduction in material costs over the machine’s lifespan. CNC mills fabricate products such as complex short-run production parts, precision components and parts, and prototype parts.
CNC turning lathes, on the other hand, are used to conduct operations such as:
CNC milling and turning are used in a number of industries, including:
Electrical discharge machining (EDM)
Metal removing (in automotive or manufacturing)
CNC Machining Services from Technox
Machining services such as CNC milling and CNC turning provide multiple options for the precise fabrication of components and parts. Each method has its pros and cons, making them ideal for different applications.
Technox operates one of the largest machine shops in the larger Chicago area. We possess capabilities to handle oversized parts and a range of value-added services that make us a single-source supplier for nearly any project. We can handle prototyping, large production runs, and everything in between.
For more information on the differences between CNC milling and turning or to inquire about our other services, please contact us or request a quote.
Milling is the process of machining irregular, curved, or flat surfaces by feeding the material through a rotating cutter with several cutting edges. CNC mills are ideal for cutting complex shapes, forming difficult-to-cut materials with high levels of precision, and come in many axis configurations and sizes. In addition, CNC milling machines can turn around parts in as little as a day, manage a wide range of production run sizes, and achieve precision tolerances.
Types of CNC Mills
CNC mills come in 3-axis, 4-axis, and 5-axis configurations:
Three-axis mills cannot manage the same level of efficiency or detail as 4-axis or 5-axis machines, but in many cases, they can produce the same products. While not as profitable or high-quality as 4-axis or 5-axis mills, these machines are suitable for:
Automatic or interactive operation
Cutting sharp edges
These mills can operate on materials ranging from aluminum alloys and composite board to foam, PCB, and wood. The 4-axis mill is a multi-functional CNC tool which features slightly improved functionality over 3-axis mills. It is often used in such applications as:
Hobby prototype building
Medical equipment creation
5-axis mills possesses the most advanced capabilities available for CNC mills. It operates far faster than 4-axis and 3-axis CNC machines and produces vertical milling at the highest quality and precision. These mills are ideal for producing:
Architectural door frames
Military grade products
Oil and gas machine parts
Titanium creations for both artistic and practical functions
Advantages of CNC Milling
CNC milling offers a range of benefits, including:
Every business looks for ways to cut costs without sacrificing quality. With CNC mills, businesses can improve the bottom line by providing significant cost savings. As CNC mills work faster and more accurately, they enable the efficient production of complex and specialized products.
Reduced labor hours also save money on expenses such as:
– Unemployment insurance
– Benefits such as health, dental, vision, and life insurance
Safety is greatly enhanced when using CNC machinery. With no bending or crouching required to operate the machines, ergonomic conditions are greatly improved for workers. This leads to fewer workplace accidents and less fatigue, largely mitigating the risk of human error in the milling process.
CNC milling machines perform non-stop with minimal necessary downtime. Facilities that run three shifts can continue production 24/7 without issue.
Versatility is one of the most significant benefits of CNC milling. CNC milling allows manufacturers to trim and shape a variety of materials without sacrificing quality or efficiency.
CNC mills are ideal for a wide variety of production run of all sizes for complex, high-quality products. CNC machines will also save a significant amount of time and money thanks to their operational efficiency and reduced labor costs.
Since 1976, Technox has offered the highest quality machining with exceptional customer service and fast turnaround times. For more information on our CNC milling services, please request a quote or contact us today.
The machining of large parts presents several challenges when compared to the fabrication of smaller, lighter components. Namely, oversized parts oftentimes must be moved quickly between tools or locations. Machining parts that are too heavy, large, or bulky to be easily moved by a single human being requires specialized equipment. Large parts may also be too large to readily fit into the work zones of most common CNC machine tools.
How Large Part Machining is Different
Large part machining may require extra steps or possess additional factors that need to be taken into account, magnified, or multiplied in order to get the job done effectively. Some of these include:
Factors that typically influence machining accuracy in a negative way are magnified when parts are larger. This means that careful consideration needs to be placed on monitoring and countering these factors. Temperature is one of the more notable and significant examples of this. The process for machining massive parts generates larger amounts of heat, so users must compensate for this heat to maintain integrity of the final part.
Material stress is yet another factor that’s frequently overlooked when smaller parts are being fabricated. Workpieces of a conventional size often leave some room for error here, but large parts do not. Stress-related distortions must be located and fixed promptly in order to keep them from negatively impacting finishing accuracy.
In the case of large five-axis machine spindles, the range of rotary-axis travel is essential. Machining large parts quickly means that the tooling range must account for the size of the design to ensure that time is not lost per part. Spindles that can reach all holes on a part at once make for faster work.
As these parts have a larger surface area, additional quality checks may be required to ensure that parts are being fabricated with reliable repeatability. Performing semi-finish passes and setting aside the time to measure between them before taking one or more finishing passes can be key to achieving strict tolerances.
Challenges Facing the Large Part Machining Industry
Large part machining offers a range of unique challenges. When implementing new processes, keep the following three obstacles in mind:
1. Implementing Large Manufacturing is a Tough Process
Implementing large part machining capabilities can be a stressful process. Investments in equipment capable of machining larger parts involves a certain amount of risk. Staff will require additional training on the new equipment to successfully fabricate oversized parts, which may cause some internal frustration or pushback from the workforce.
2. Buying in at the Shop-Floor Level
The individuals who will be doing the legwork behind large manufacturing need to be invested in the process. Any shop relies on the experience and abilities of its workforce to drive success. Without support at the ground level, new large part initiatives will suffer.
3. Don’t End Experiments Prematurely
It takes more time than many professionals may expect to fine-tune a large part manufacturing process and get it right. Stumbling along the way and needing to adjust your process is normal, but not everybody has an easy time coming to terms with this. It’s easy to think your process is broken or ineffective when it’s in its infancy, and this is how many larger projects fail.