Essential Guide to Machining in Manufacturing: Processes and Benefits

Overview of Machining in Manufacturing

Machining is a technical and meticulous process in modern manufacturing. It involves cutting a blank/raw material in a controlled manner and shaping it to the desired form. The techniques of this approach employ machining centers, a principal machine tool capable of performing multiple operations in a single setup. Manufacturers employ machining processes to work on large quantities of metallic and non-metallic materials.

The history of machining in manufacturing dates back a few centuries. Machining processes were mainly used to repair machines and equipment, using hard-working processes like turning, drilling, reaming, and more. Operators execute these machining processes using manual tools including simple lathes, cutting tools, drill presses, or drilling tools.

How Does Machining Work

Machining begins with gradual removal from a bigger material than the desired workpiece. Computer numerical control (CNC) technologies manage the performance of machining tools in the modern manufacturing landscape. The concept of machining is a structured process that begins with a conceptual design of the required shape and then transits to the execution of design on the machining tools.

Step-wise Guide to the Machining Process

We’ll explore the different stages involved in the machining process in this section:

Developing a Blueprints

The first machining stage involves creating a conceptual idea of the required finished product. It involves making the engineering drawing and blueprints of the preferred part, specifying the intended dimensions. However, it is crucial to consider every material’s machinability and mechanical strength when determining the dimensions. For example, ensure the machined parts have a minimum thickness to avoid the parts collapsing in the machining stage itself.

Designing CAD Models

The programmer converts the blueprints of a part into a digital 3D model using CAD (Computer Aided Design) software. However, the CNC machine requires complex CAD programs to create parts with intricate designs. These CAD models are changed to Computer Aided Manufacturing (CAM) programs. The CNC machine understands the CAM program and can identify any design errors affecting the machining operation.

Setting up the CNC Machine

The machine operator puts the machine for the machining process. This stage involves adjusting the tooling and mounting the workpiece materials on the CNC machine. However, the machine setup varies based on the chosen machining process. The transfer of the CAD instructions to the machine is also a procedure in machine setup.

Program Execution

The machinists execute the program once the machine is ready. A CNC machine follows the program to shape the material into the desired form. Program execution occurs in several ways depending on the machine in use. The final part is ready and removed by the operator after the program execution. Nevertheless, the machinists perform further post-machining operations depending on the design requirements.

Benefits of Machining in Manufacturing

Manufacturers have utilized machining techniques due to their vast benefits, including:

Higher Production Rate

Since machining processes are usually automated, they facilitate rapid production to reduce cycle times and ensure faster time to market machined components. Multi-axis machining increases throughput and efficiency compared to manual methods.

High Precision

Manufacturers achieve better precision with CNC machining compared to other machining processes. It offers some of the lowest achievable tolerances in industrial manufacturing processes. Precision machining processes can obtain machining tolerances as low as .001” since the cutting tool removes material according to preprogrammed computer software. Hence, machinists can create components with exact dimensions and the tightest tolerances.

Less Labor Intensive

Modern machining technologies are highly versatile and automated equipment capable of reducing human labor for high-priority tasks. All these CNC machines require little to no intervention by the operator once programmed. Therefore, machining lowers the need for extensive labor while cutting labor costs and ensuring consistent quality.

Surface finishing

Machining processes such as grinding and milling operations provide high precision and excellent surface finish on the machine parts. High-quality surface finish in machined parts helps to ensure they meet their intended applications’ requirements. Moreover, excellent surface finishes enhance finished parts’ aesthetics, performance, and longevity.

Consistency

Machining techniques provide incredibly consistent outcomes. Consistency is a principal requirement for most industries in mass production runs to create identical parts and lower errors.

Common Limitations of Machining

Although machining is a versatile approach in modern manufacturing, it presents certain challenges, such as:

High Initial Cost

Industrial machining setups usually have high initial costs. Although multi-axis milling machines are a perfect choice for rapidly manufacturing complex parts, their high cost often discourages manufacturers from purchasing these machines.

Skilled Operator Requirement

Machining prioritizes the need for skilled operators even though it reduces human labor. Complications such as low-quality production, damaged machined parts, or even damage to the machine can occur if an unskilled operator manages your machining tasks. More particularly, you need a skilled programming team to handle the production of highly complex products.

Material Wastage

Machining techniques work by gradually removing unwanted material from the blank, resulting in high material wastage. Even though manufacturers recycle materials and sell them as scrap in some cases, recycling or disposing of this material in several other cases can be challenging.

Limitation to Machinable Surfaces

When machining a workpiece, there is a restriction to the number of machinable surfaces. It is usually impossible for the rotary cutting tool to cut the area under the clamps and the side touching the worktable. As such, the machinist must unmount the workpiece, adjust its orientation, and re-mount it to machine these areas.

Outsource your machining requirements to a third-party manufacturer like AT Machining to avoid these setbacks. It is the ideal solution for your project as our professionals can leverage our modern machining equipment and wealth of experience in machining different materials with machining techniques.

Standard Machining Processes Used in Manufacturing

Various machining processes and operations have their purposes and designs in manufacturing different products. Below is an overview of these different types of machining processes:

Milling

Milling is a versatile machining process involving a high-speed rotating cutting tool against the workpiece to achieve precise dimensions. It can create different complex shapes, making simple straight cuts to angled and inclined surfaces for specific purposes. Standard milling tools include column mills, bed mills, knee mills, gantry mills, ram-type mills, turret mills, c-frame mills, and more. Machinists often use different milling machines and processes to create automotive parts, agricultural equipment, and gears, making slots and grooves in workpieces.

Drilling

It is a standard machining process used to create holes using drill presses for independent professionals and small-scale workshops. These holes serve different purposes, including inserting screws, improving aesthetic appeal, or secondary assembly. Product manufacturers often drill holes in fuel injector bodies, screw holes, fluid assembly ends, aircraft landing gear, and heat exchanger tubes.

Grinding

The grinding process involves using abrasive wheels or surfaces known as grinding wheels to remove a small amount of material from a workpiece to achieve a smooth surface and ensure exact dimensions. Manual and computerized grinding tools are the standard tools used in grinding operations. Die grinders, bench grinders, and angle grinders are commonly used grinding tools. Machinists often adopt grinding in precision machining, surface finishing, deburring, and descaling.

Turning

Turning is one of the standard conventional processes operators use in machining required parts. In turning operations, the stationary cutting tool shears material from a workpiece rotating around a central axis at high speed. Turning is a standard process for the symmetrical shaping of a raw material. Computer numerical control guides rotating cutting surfaces when making cylindrical shapes or conical-shaped parts. Typical applications of the turning process include engine components, shafts, and machine components. Machinists often use turning to create threads, tapers, helical grooves, and different diameter steps for machined parts.

Boring

Boring is similar to turning only when boring tools work on the internal diameter of a workpiece. Boring tools are often used to widen previously drilled holes in the workpiece. Machinists usually perform the boring task with a single-point cutting tool or an assortment of such tools. Mining, crane end loaders, engine cylinders in the automotive industry, mining, firearms, and other cylindrical parts are typical boring applications.

Reaming

Reaming is a common machining process that uses different tools to slightly enlarge the diameter of existing holes and add an internal surface finish. Machinists use this process to achieve a very precise hole diameter or surface finish when drilling tools cannot achieve the desired results. The reaming process involves drilling an undersized hole in a workpiece and then using reaming tools to widen the hole to the precise width and finish. Applications of the reaming process include landing gear, aircraft components, fuselage, and engine parts.

Planing

It is another subtractive manufacturing process that involves using a machine called a planer to create flat surfaces on machined parts. The planer uses the relative motion between the workpiece and a single-cutting tool to perform the cutting action. Typical applications of planing include the creation of multiple slots at the same time, generating flat surfaces for any requirement, and woodworking. While planer tools can accurately produce flat surfaces, curved planers can create curved ones.

Sawing

This machining process is one of the earliest forms of machining technique. Sawing involves using a sharp blade with a toothed edge, wire, or chain to shape wood, metals, or stone into desired shapes. Various manual and CNC machine setups often possess sawing tools. Wood cutting, house making, tile cutting, and furniture making are typical sawing uses.

Broaching

Broaching involves using a toothed cutting tool, a broach, to remove unwanted material from a workpiece. This process occurs in two ways: linear and rotary. This machining method is ideal for the precision machining of complex geometries. Internal keyways, non-circular holes, stampings, non-circular holes, splines, and screw machine parts are typical components manufacturers produce with the broaching technique.

Erosion Machining Techniques

These advanced, non-conventional machining techniques remove material from a workpiece using chemical erosion, electrical, or thermal mechanisms instead of traditional cutting tools or mechanical force. Manufacturers achieve erosion machining in different ways, including:

• Electric Discharge Machining (EDM): EDM, also known as spark machining, wire erosion, or spark erosion, is a versatile machining technique that uses controlled electrical discharges or rapid sparks between an electrode and the workpiece submerged in a dielectric fluid to erode material from electrically conductive materials like titanium, hardened steel, and tungsten.
• Water Jet Cutting: Water jet cutting employs high-velocity stream water (sometimes mixed with abrasive substance) to cut material materials, such as thick metals, ceramics, glass, wood, plastic, stone, and rubber. Machinists often add abrasive materials to the water stream for improved cutting power. Depending on the number of axes the machine uses, machinists can achieve intricate shapes and dimensions. This technique is used in paper, food, mining, surgical equipment, and art installations.
• Ultrasonic Machining: This mechanical erosion process uses a high-frequency vibrating tool to remove material from a blank. An abrasive material is present between the cutting tool and the workpiece, which mixes with water to form a fine abrasive paste. The cutter vibrates at a high frequency and uses the abrasive paste on the tip to remove material gradually. Applications of ultrasonic machining include electrical equipment, glass cutting, machining of sensitive materials, and optical equipment.

Thermal Cutting Techniques

Thermal/burning machining techniques use a high temperature to remove material from a workpiece, unlike the sharp cutting tool employed in conventional machining methods. The burning tools apply heat, which melts the removed material:

• Plasma Cutting: Plasma cutting is an advanced machining technique involving the use of a stream of ionized gas to melt and remove material from an electrically conductive workpiece. Machinists utilize this technique in machining metals and conductive alloys.
• Laser Cutting: Laser cutting uses a highly focused light beam to remove material from a workpiece to achieve any shape required. The process is one of the most precise cutting techniques compatible with metals and non-metals.
• Oxy Fuel Cutting: This is an ancient machining technique known as gas cutting. It involves using a mixture of oxygen and combustible fuel gas like propane, acetylene, natural gas, or propylene to remove material through melting. Although it is not as precise as plasma or laser cutting, the equipment is highly portable. Stone-working, welding, hard facing, and loosening seized fasters are the typical uses of the oxy-fuel cutting process.

CNC machining

CNC machining is a technology applicable to other techniques in manufacturing. It represents Computer Numerical Control (CNC) and facilitates the automation of machines. Although it requires a skilled operator and high initial costs, the CNC machining approach saves time and labor costs. Manufacturers in all modern industries commonly embrace this technology in scenarios when precision and high production rate is necessary.

Precision Machining

Precision machining is a more advanced use of CNC machining involving the use of CNC machining, where the machined parts are produced with a higher accuracy and precision. This approach involves different machining techniques discussed above, with the highest quality standards in the cutting tools and other aspects. Product manufacturers usually adopt precision CNC machining in applications where consistency is critical on a micro or nanoscale, such as in aerospace, electronics, medical, military, etc.

Materials Compatible with Machining Techniques

Machining techniques in manufacturing are compatible with a wide range of materials, including:

Aluminum

Manufacturers across industries utilize aluminum and its alloys due to their low weight and high strength. As such, aluminum alloys are commonly used machining materials in aerospace, architecture, automotive, construction, and medical industries. Machining processes work well on aluminum grades like 5083, 6061, 6082, 7075 etc.

Brass

Brass is a common material that works well with high-speed machining. It exhibits a distinct blend of properties such as aesthetic appeal, good forming, corrosion resistance, and thermal conductivity. Its typical applications include decorative components, fittings, and fasteners.

Copper

Copper is another highly machinable material with exceptional properties, including high strength and electrical conductivity. As such, its typical applications include plumbing, heat exchangers, and electrical components. However, it is essential to use proper tool coating and lubrication when machining copper since it usually becomes gummy during machining.

Titanium

Titanium is one of the hardest machining materials for manufacturing durable metal parts. Manufacturers often choose titanium for machining applications requiring titanium’s high strength and density. However, titanium machining usually requires slower cutting speeds, sharp cutting tools, and adequate coolant supply to manage generated heat.

Steel

Steel is a rugged and highly versatile, common precision machining material. It is an alloy of carbon and iron. Steel materials are available in different varieties based on the carbon content in their composition. All these grades of steel are easy to machine. Stainless steel, alloy steel, mild steel, and carbon steel are typical steel variants.

Wood

Wood is another machining material with attributes that make it a right fit for different applications. The woodworking machine shops have been standing for a long time. Most woods are lightweight and easy to machine. More importantly, they offer natural colors and textures that can be improved with machining and finishing processes. Wood machining applies to carving, furniture making, and many other applications.

Plastics

Plastics are of different types, including thermosets and thermoplastics. Plastic machining allows machinists to achieve higher precision in machining plastic components than other processes, such as 3D printing or injection molding. Nylon, PMMA, polycarbonate, silicone, polyurethane, and PEEK are typical plastics used in machining projects.

Essential Skills for Quality Machining Projects

Machining requires various technical and practical skills to achieve optimal results or efficiently execute complex projects. Below are some of the essential skills fundamental to machining:

• Graphics Design: Graphic designs of the desired parts are necessary before initiating a machining project. This skill is key in creating and interpreting the graphical design in 3D, translating ideas into machinable parts. 
• Computer Programming: This is another fundamental skill in machining precision CNC parts. Computer programming ensures precision and repeatability by drafting G-code or generating toolpaths with CAM software. Computer programming skills allow product manufacturers to customize machining parameters to meet the requirements of complex operations.
• Mechanical Engineering: Mechanical engineering skills aid a clear understanding of different machining materials’ strengths, limitations, and usability. Besides, machinists attain accurate and efficient material removal in machining processes with the proper knowledge. Lack of this machining skill can influence the quality of machined parts during and after machining.
• Operator Skill:  Operators’ skills often vary based on the chosen CNC machine. Skilled operators exhibit practical and precise execution of machining projects through training and experience in effectively operating manual and CNC machines.

Conclusion

Modern manufacturing thrives exceedingly on machining processes, with several machine shops embracing various methods to create precise parts or make necessary tools for creating diverse products.

AT-Machining is a leading machine shop in the world capable of meeting your machining project’s demands. We leverage our modern machining facilities and experience in different machining processes to handle your project from prototyping to mass production. Contact us today for reliable engineering support, free quotes, and DFM analysis.

FAQs