Manufacturing accounts for 11% of the U.S. economy. At the heart of the manufacturing sector is machining technology. Machining processes are essential in just about every critical industry – from aerospace and automotive to the medical sector. Engineers rely on these processes to remove excess material during part production. With the dynamic nature of manufacturing demands, machining processes are constantly evolving. Each of these processes plays a significant role in refining manufacturing outcomes. Below is a guide that explores the different types of machining processes that engineers need to know and how that knowledge assists in part design.
1.) CNC Milling
CNC milling employs computerized controls to direct multi-point rotary cutting tools as they move a workpiece’s surface. This precise movement and rotation eliminate surplus material, sculpting the workpiece into the desired size and shape.
The CNC milling process features four distinct stages:
- CAD Model Design: Engineers craft a 2D or 3D model of the desired component with CAD software. This digital blueprint is the foundation for all subsequent manufacturing processes, ensuring precision and adherence to technical specifications.
- CAD Model Conversion to CNC Program: The CAD model undergoes conversion into a CNC-compatible file format. Next, Computer-Aided Manufacturing (CAM) software translates this model into a set of machine instructions known as G-code. This guides the CNC milling machine’s movements.
- CNC Milling Machine Setup: The machine operator gets the CNC milling machine ready. This involves configuring the tools, securing the workpiece, and inputting the CNC program into the machine’s control unit.
- Milling Operation Execution: The machine operator starts the machining program. As a result, the CNC milling machine executes the programmed instructions.
CNC milling machines can vary in their configurations, with options including:
- Stationary workpiece with a moving rotary tool
- Moving the workpiece with a stationary rotary tool
- Both workpiece and rotary tool are in motion
These machines can craft design elements like contours, grooves, flat surfaces, slots, holes, notches, and pockets. Engineers often utilize CNC milling to create precise parts for various industries, such as aerospace.
2.) CNC Turning
CNC turning is a precise subtractive machining process akin to a lathe machine. It involves a stationary cutting tool making contact with a rotating workpiece to remove material to get the desired shape.
This process includes:
- CAD to CNC Conversion: The process starts with a 2D CAD drawing, electronically captured using software like AutoCAD. Then, convert it into a CAM program to test manufacturability.
- Machine Preparation: Secure the workpiece onto the chuck, ensuring stability during turning. Next, load the tool turret with the appropriate tools and calibrate the setup. Finally, upload the CNC program into the machine. For optimal results, ensure you determine the turning speed and feed rate.
- Manufacturing: Choose the turning operation based on the desired outcome and complexity. To get cost estimates, calculate cycle time.
CNC turning is ideal for crafting cylindrical or oblong components. This CNC machining service can also produce axially symmetric shapes like cones and disks. It is ideal for manufacturing parts such as shafts, bushings, connectors, and more.
3.) Electrical Discharge Machining (EDM)
A deep understanding of the Electrical Discharge Machining (EDM) process empowers engineers to design parts with enhanced precision and efficiency. EDM, a non-traditional, precision machining method, involves material removal through controlled electrical discharges. This machining process eliminates the need for mechanical force. Different types of engineers will use it for hard materials and intricate shapes. There are three types of EDM-wire EDM, hole EDM, and sinker EDM. Wire EDM is suitable for producing complex contours, while hole EDM is used for creating small, precise holes.
Generally, the EDM process includes:
- Material Removal: Rapid current discharges between two electrodes separated by a dielectric fluid precisely removes material. The workpiece acts as the anode, while the tool electrode serves as the cathode. They must not contact each other.
- Heat Generation: Voltage is then applied, causing the material to heat and melt. This intense localized heating is a result of the electrical discharges occurring in the tiny gap between the electrodes.
- Cooling and Debris Removal: The dielectric fluid flows steadily, removing excess material and cooling the area.
When traditional manufacturing processes reach their limits, EDM is your go-to machining operation.
4.) Laser Cutting
Laser cutting employs a high-powered laser beam to cut or engrave materials precisely. It operates in both continuous and pulsed modes.
The laser-cutting process involves the following steps:
- G-Code Loading: Instruct machine movements to start the process
- Laser Generation: The resonator produces a laser beam, often infrared in CO2 lasers
- Beam Direction: Mirrors or beam benders redirect the laser to the focusing system
- Focusing: A lens narrows the beam, boosting its power and ensuring a precise, round focus
- Material Interaction: The concentrated beam melts the material at the contact point
- Cutting Path: The cutting head moves as per G-code directions, adjusting speed for specific tasks
Laser cutting is vital for contract manufacturing companies as it offers precision and versatility. For instance, it allows for the manufacturing of precise electronic enclosures and printed circuit boards (PCBs).
5.) Water Jet Cutting
Water jet cutting utilizes a high-pressure stream of water, often mixed with abrasive particles, to cut a wide range of materials precisely. There are two types of water jet cutting processes: pure and abrasive water jet. Engineers in the energy sector utilize this process to create parts for power generation and transmission.
The steps of the process include:
- Generate Pressure: A high-pressure pump pressurizes water up to 100,000 psi (approx. 6900 bars). This far exceeds standard fire hose pressures (8-20 bars).
- Form a Stream: Water travels through high-pressure tubing and is funneled through a nozzle. This transforms it into a fine, potent stream.
- Material Interaction: The high-velocity stream shears through the different types of materials placed before it. For precision, engineers use a vision system.
Water jet cutting can also be used to cut more rigid materials. Abrasive particles are often introduced into the water stream to cut harder materials such as metals. Once the abrasive water jet is directed onto the target material, it cuts through it.
6.) Grinding
Grinding involves using abrasive particles to remove material, refining the shape and surface of a workpiece. This process often employs a grinding wheel or belt as its primary cutting tool.
Ideal for burr removal and specific surface finishing processes, grinding typically involves:
- Material Removal: Uses abrasive grains within the grinding wheel to remove material from the workpiece.
- Precision: Achieve finer surface finishes.
- Wheel Maintenance: Dull grains are removed through dressing, and reconditioning of the wheel occurs.
The workpiece is either manually or power-fed past the grinding wheel, ensuring precise material. Grinding is often used to create precise components for medical applications, such as surgical instruments or implants.
7.) Plasma Cutting
Plasma cutting is a melting process using a high-velocity jet of ionized gas at temperatures above 20,000°C to melt, sever, and expel material from the cut. This process utilizes an electric arc between an electrode and the workpiece, confined by a gas nozzle. The arc creates a high-speed plasma jet, the jet melts the metal, and the gas flow removes the molten debris. Engineers can use plasma cutting to fabricate components such as automotive parts like chassis components and exhaust system elements; they can also create intricate body panels for improved vehicle performance and safety.
How does having in-depth knowledge of these machining processes help you design better parts?
Machining technology and an in-depth knowledge of how these processes work is an integral part of modern manufacturing and a key component of designing overall better components. At O&Y Precision, we are equipped with unparalleled expertise in a wide range of machining operations.
Milling & Turning
Designing for CNC milling and/or turning requires engineers to possess a range of technical knowledge for efficient and accurate manufacturing. A solid grasp of Geometric Dimensioning and Tolerancing (GD&T) is essential to convey precise specifications for part features and tolerances. Engineers must understand material properties and select appropriate materials considering factors like machinability and surface finish requirements. Engineers must be adept at dimensioning critical features, machining allowances, and specifying internal and external radii to avoid stress concentrations. Thoughtful inclusion of hole specifications, fillets, and chamfers contributes to part strength and aids in machining. Consideration of part orientation during machining and awareness of toolpath interactions are critical factors for optimizing CNC milling and turning processes. Collaboration with machinists, explicit annotations, and comprehensive documentation ensure the design intent is accurately translated into the final parts. Proficiency in CAD software and an understanding of the unique aspects of CNC milling and turning contribute to the overall success of the manufacturing process.
Electrical Discharge Machining (EDM)
Better understanding essential factors such as electrode geometry, spark gap, and dielectric fluid properties can help empower engineers to create parts that meet functional requirements and leverage the unique advantages of this advanced machining process. Knowledge of the process’s inherent capabilities and limitations allows for the creation of intricate and complex features and the selection of materials suitable for EDM. Designers can strategically place features to minimize electrode wear and ensure consistent material removal throughout the machining process. Awareness of EDM’s influence on material properties, such as recast layer formation, also aids in specifying proper post-machining treatments. Additionally, understanding the impact of EDM parameters on surface finish and accuracy enables engineers to tailor designs for optimal results.
Laser Cutting
Engineers well-versed in laser cutting can strategically design parts by considering factors such as material selection, thickness, and the intricacy of cuts. They can exploit the precision and flexibility of laser cutting to create intricate geometries and fine details. Knowledge of the heat-affected zone and potential material distortions enables engineers to anticipate and mitigate issues, ensuring the final part meets dimensional accuracy requirements. Understanding the limitations of the laser cutting process, such as the maximum thickness a laser can effectively cut, helps design parts that align with manufacturing capabilities. Furthermore, awareness of different laser types and their varying capabilities allows for tailored designs that optimize speed and efficiency. Integrating knowledge of laser cutting into the design process enables engineers to create parts that fulfill functional needs and leverage the precision and versatility offered by this advanced machining method.
Water Jet Cutting
The non-thermal nature of water jet cutting makes it suitable for various materials, including metals, plastics, and composites, allowing designers to explore a broader range of material options. Knowledge of the kerf width, or the amount of material removed during cutting, helps engineers account for tolerances and design parts with meticulous accuracy. Creating intricate shapes without introducing heat-affected zones enables engineers to design complex geometries with minimal material waste. Understanding the limitations and capabilities of water jet cutting machinery allows for the optimization of cutting speeds and the avoidance of potential challenges. An in-depth knowledge of the water jet cutting process can empower engineers to create parts that leverage the advantages of this versatile and precise machining method.
Grinding
Knowledge of different grinding methods, such as surface grinding or cylindrical grinding, allows engineers to tailor and optimize part designs for efficiency and attain high-quality surface finishes. Understanding the interplay between grinding wheel properties, such as grit size and bond type, helps in optimizing material removal rates and achieving desired surface characteristics. Precision in part dimensions, tight tolerances, and avoidance of heat-affected zones are critical considerations in the design process, as they directly impact the success of the grinding operation. Engineers with a grasp of grinding capabilities can design parts with intricate features and ensure that the final product meets the required specifications for functionality and aesthetics.
Plasma Cutting
Knowledge of the intricacies of plasma arc behavior allows for precise control over cutting paths and minimizes the heat-affected zone, contributing to dimensional accuracy. Additionally, awareness of plasma cutting’s ability to produce smooth edges without the need for secondary finishing aids in designing parts with specific surface finish requirements. Understanding the limitations of plasma cutting, such as its impact on material distortion and achievable tolerances, enables engineers to design parts that align with the capabilities of the machining process.
Get Ahead of Your Project Goals
At O&Y Precision, Inc., our seasoned machinists are committed to your success by ensuring quality parts, competitive pricing, and guaranteed on-time delivery. So why not leverage our expertise for your next project?
How can O&Y Precision, Inc. help you?
O&Y Precision, Inc. is a quality-driven manufacturing company focused on providing top-notch custom parts, on-time delivery, and building long-lasting relationships. Our word is our bond. Whether your project is a quickly needed, a small quantity prototype, or a full production run, we will make it happen – on time, guaranteed. Contact us today with any questions or to get started on your next project, and let our O&Y Precision Machine Shop expert team bring your vision to life!
