CNC vs Manual Machining: Why are CNC Machines far Better Than Manual Ones

Old manufacturing and production shops and experienced machine operators recall a time when manual machinery dominated the work area. End mills, face mills, and other cutting tools were utilized to execute various milling operations on these reasonably multipurpose milling machines. 

However, in today’s technology-enabled manufacturing arena, CNC machines have emerged as a prized possession of machine shop owners, with manual milling machines consigned to support functions and modest repair and maintenance tasks. Manual labor has also made way for a tech-savvy CNC machinist who can control a CNC machine to perform operations that were unthinkable some decades before. 

Here is a comprehensive guide offering a comparison of CNC and manual machining. It also covers crucial features of CNC machines that make them superior to manual ones while involved in high-end manufacturing and production operations. 

A Brief Comparison of CNC and Manual Machining Working Principles

Let’s start with a fundamental understanding of the underlying operating principles of both machining types. 

Working Principle of CNC Machining

Computer Numerical Control (CNC) machining requires developing digital product or component design files containing cutting and tooling specifications. As a result, the CNC machine technique necessitates leveraging numerous tools for fabricating machined components, and designers and skilled machinists create digital tool libraries to interact with CNC equipment.

These devices can be handled autonomously through computerized commands and CAD-CAM software solutions. The software’s 3D model defines the final product’s requisite attributes, quality, and parameters.

Working Principle of Manual Machining

We use hand controls to operate manual machinery such as drill presses,  bandsaws, grinders, lathes, endmills, etc. Machinists could produce a broad range of prototyping products for a spectrum of applications with this machinery. Manual machining demands more time investment and effort to execute any operation than CNC machining, which gets operated autonomously.

Three Prominent Types of CNC Machining and Their Benefits over Manual Machining

1. CNC mill machine

CNC milling is a standard process for manufacturing intricate components. It employs a rotating cylindrical tool for material removal from a workpiece fixtured to a tabletop by connecting with a movable, rotating tool, thus producing custom-designed products. CNC mill cutting tools have several degrees of freedom and can operate along different orientations for milling the part and rotating in X, Y, and Z axes with a single fixture. CNC mills are ideal for high-accuracy, high-speed fabrication since they are capable of drilling, making slots, leveling, grooving, and engraving material.

CNC mills offer greater precision than manual mills, thanks to their integration with computer technology for orientation, depth control, and speed. A person controlling a manual mill can’t make real-time computations or translate friction into feedback to achieve accurate results as software can. Also, manual mills can only remove material in a single plane at one instance, severely limiting productivity.

2. CNC lathe machine

CNC lathe machines are typically employed in manufacturing components utilizing accurate design dimensions, parameters, and specifications. Material clamps and spindle rotation are utilized in lathe machines for metalworking, woodturning, and thermal spraying operations. In addition, the CNC lathe machine can create cylindrical, conical, or flattened surface geometries. They can also change the surface roughness, friction, chamfer characteristics, and product aesthetics of machined components.

CNC lathes have largely superseded manual lathe machine setups, which require highly experienced operators with years of industry training and experience. One can only use manual lathes for producing prototypes by manually switching machines. Also, manual lathes need to be installed and configured manually, lack the accuracy of CNC versions, and offer far poorer throughput.

3. CNC Electric Discharge Machine

The most sophisticated CNC equipment in the category is an Electric Discharge Machine (EDM). Electrical discharges or sparks are utilized in the machining operation for material removal from a workpiece immersed in a dielectric medium and held between two electrodes.

To produce the required designs and dimensions, the computer determines the amount of voltage that needs to be discharged throughout a dielectric fluid. The component is submerged in the dielectric medium either partly or entirely. But a direct connection is not established with the tooling; instead, the electrical discharge serves as the cutting tool.

If the processed components exhibit conductive properties, EDM operations can substitute practically every physical machining operation, even those done on mills and lathes. Although wire EDM is more expensive, the accuracy and configuration offer an excellent cost-to-benefit margin.

Now that we have covered the significant types of CNC machining, it’s time to summarize and compare the benefits of CNC and manual machining. 

Top Four Vital Benefits of Leveraging CNC Equipment in Machining Operations

1. CNC machines are accurate and versatile

One distinguishing quality of CNC machining is its adaptability and accuracy. CNC machining is used to produce parts and accessories for various industrial sectors due to its accurate component fabrication, economical manufacturing, and uniform cutting. Furthermore, customized metals can be produced using CNC machines and technology. We can leverage this technology for both- material cutting and large-scale part manufacturing. A trained expert can easily control many CNC machines.

2. CNC equipment exhibits reliability and effectiveness

CNC machining gets controlled by computers, and there is no room for operator error. Also, autonomous operation implies that  CNC machining is more dependable and faster than manual machining. Simply stating, CNC machining is more efficient and takes less time to manufacture.

3. Requires less human labor and has a minimal maintenance demand

Operating CNC machines do not require a large pool of experienced and trained operators during manufacturing and production operations. Most of the manufacturing activities can be carried out by only a single qualified machinist. And, despite running for the whole day, CNC machines require lesser maintenance and servicing than manual ones. They only need to be serviced occasionally.

4. Helps achieve design consistency, dimensional accuracy, and safety

One of the top benefits of CNC is that it can reproduce the same design consistently when the dimensions, design parameters and specifications, and coding for some parts are exactly the same. As a result, this technique improves profits significantly while reducing efforts and production expenses. Furthermore, CNC machines are safe to operate. Operators function distantly from the machines and have no direct attachments to CNC machining.

Top 4 Benefits Offered by Manual Machining

Even though CNC machining has a technically advanced capability to make top-quality machining parts, manual machining offers value. The benefits of manual machining are as follows.

1. More affordable for modest production

Manual machining is less expensive for small-to-medium scale manufacturing projects and low-budget enterprises. It is a viable choice for newly established businesses because they don’t need as many parts or resources to run.

2. A wise selection for manufacturing metal shapes

When using manual machinery, the manufacturing process takes longer and requires more resources and tools. So it is ideal to employ this technique for micro-operations and fabrication of uncomplicated, smaller parts. For simple metal designs, the manual machining technique is highly recommended because it works out to be less expensive than alternative procedures.

3. No programming/coding required

 For CNC lathes to function properly, a considerable level of programming is necessary. This much investment of time and effort is not required for small-scale manufacturing processes. We don’t have to be concerned about programming or the time needed to ensure the parameters are accurate when manual milling is used.

4. Quicker turnaround for smaller operations

Getting a component ready typically takes less time when milling manually since there are fewer processes involved than with CNC milling.

Now that we have compared the perks of employing CNC and manual machining for our part manufacturing and production operations, it’s time to consider the overall cost and industrial implications for deciding on the better machining technique.

A Comparison of the Cost and Industrial Implications of CNC and Manual Machining

Compared to manual versions, CNC machines are quicker and generate less waste. It has been demonstrated that manual machines with a CNC upgrade could manufacture parts 75–300% quicker. By employing fewer workers to make each component, boosting throughput brings down component costs.

Additionally, a CNC machine can switch tools four times more rapidly than manual equipment. Hence, the turnaround time for delivering finished products to clients is significantly reduced. Because of their greater precision and accuracy, CNC machines also boast a reduced scrap rate, resulting in cheaper part costs.

A reduction in scrap rates not only implies more profitability for the business but efficient, top-quality machining also substantially reduces the customer dissatisfaction/rejection rate. The probability of overlooking production defects during the inspection gets minimized when we utilize a more accurate, systematic process. It keeps the client from receiving quality defects, which promotes customer loyalty.

Now, let’s talk about the widespread applications of CNC machining across several prominent industries that give them an upper hand over manual machining equipment. 

Top 7 Key Industries That Utilize the Services of CNC Machining

1. Automotive sector

CNC machines are used in the automotive industry to build sophisticated engine components such as the engine compartment, crankshaft, and transmissions from a wide range of engineering resources.

But the excellent reproducibility of CNC machines is what makes them so valuable in the auto sector. Automobile manufacturers produce millions of parts in bulk. Only some production processes, including CNC machining, can achieve these stringent repeatability demands. It is not possible with manual machining. 

2. Electronics industry

For the past few decades, CNC machining has been at the vanguard of production technology utilized in the electronics space. CNC machines are typically used to make critical electronic components such as printed circuit boards (PCBs), jigs, heat sinks, sockets, and connections.

Also, the application of CNC has picked up in the consumer electronics market with large-volume manufacturing of smartphones, mics, laptops, and other accessories.

3. Defense and aerospace sector

The aerospace and defense industry is renowned for demanding incredible precision, perfection, reliability, and tight tolerances. To manufacture these components and meet the stringent tolerance requirements, the defense sector mainly relies on 5-axis CNC milling machines. The CNC technology is effective for components that require consistent innovation and high levels of security.

Furthermore, multi-axis CNC machines are assisting the aviation industry in processing difficult-to-fabricate metals such as titanium.

4. Medical industry

To cater to the patient’s healthcare needs, the medical sector employs a variety of customized physical implants. These implants must be exceedingly precise and reliable because even minor errors could harm the patients’ health and deteriorate their quality of life.

Medical specialists design patient-specific implants utilizing reverse engineering and CNC techniques, typically made of titanium and other biocompatible substances that are difficult to machine using conventional manufacturing methods.

5. Semiconductor technology

The semiconductor technology sector values CNC machines for their compatibility with several engineering materials and their capability to manufacture products with high dimensional accuracy. CNC machines make it simple to create several parts for electronic and integrated circuits composed of silicon, aluminum, and alumina.

Additionally, semiconductor manufacturing companies can obtain a variety of top-quality surface finishes, such as masked, anodized, and nickel-plated finishes, thanks to CNC machining.

6. Energy sector

Multi-axis CNC milling equipment comprises a list of few manufacturing technologies that can create the incredibly complicated parts required for advanced solar, wind, and hydroelectric generators and turbines.

In the energy sector, CNC EDM is also useful for producing compact and intricate components, specifically when using manual machining tools that could damage the component from excessive cutting tool stress. This is because, during machining procedures, CNC EDM does not have immediate contact with the workpiece.

7. Oil and gas sector

The oil and gas companies use CNC milling machines for bulk-volume production of connecting rods, pins, valves, bearings, and pistons. CNC machining is the optimal process for achieving precise, high-strength, top-quality, oxidation-resistant, tight-tolerance products that can function reliably in the extreme operating environment of escalating temperature and pressure. Such parts fitted in pipelines and refineries hold immense value in the sector’s business operations. 

Conclusion

Being in the manufacturing and production business, we need to comprehend the perks offered by CNC machining over manual methods. An important thing to remember here is that manual machining should always have a place for recreational, prototyping, and woodworking applications. CNC machining is a tremendous improvement for medium-to-large scale industrial manufacturing and production.

CNC machines not only produce parts more quickly, but they also produce more accurate parts with less scrap and less effort. Additionally, they speed up production, which boosts client satisfaction. Therefore, despite the fact that manual machining aficionados may not favor evolution, they enjoy generating more revenue and keeping their clients satisfied. And CNC machining technology just makes it simpler to achieve all of it.