Comparing CNC Machining vs Manual Machining: Which Technique Is Best

CNC machining, which can also be referred to as “computerized digital control”, has become a faster and more efficient way of manufacturing. It is a type of machining that is controlled by a program. A software-controlled milling, turning, or EDM machining removes layers of material from the workpiece to create the desired part. Manual machining, on the other hand, can only be done manually by a skilled machinist. Finally, when comparing CNC machining to manual machining, the benefits of CNC machining seem endless.

However, there are some companies that only use manual machining tools to create prototype parts. Hand machining is important, especially in the commercial sector and when making small quantities of rapid prototypes.

For a project to be successful, you need to choose the right machining production method. Below is a comprehensive comparison of CNC machining versus manual machining to help you decide which method is best for your business. It will help you make the best choice for custom prototypes and final production parts.

What Is CNC Machining?

CNC machining is a technique whereby a machine tool is controlled by a computer program to perform various machining tasks. These tasks include cutting, drilling, milling, etc., enabling high-precision machining of materials. CNC machining is widely used in the manufacturing industry because it increases productivity while ensuring machined parts’ consistency and accuracy.

In CNC machining, a computer program controls the tool’s movement and the workpiece’s machining process through the CNC machine’s controller. Compared to traditional manual operations, CNC machining reduces human error and allows for the mass production of complex shapes.

How Does CNC Machining Work?

• Machine Setup: Before machining begins, the operator prepares the CNC machine, including mounting the workpiece and tooling, and checking the condition of the equipment to ensure machining accuracy.
• Program Execution: A pre-written CNC program is entered or uploaded via computer and the machine automatically performs the machining tasks according to the instructions in the program. The program will control the machine’s axis movement, tool selection, cutting speed, and other parameters to complete the specified machining.
• Feedback and Adjustment: During the machining process, the operator monitors the machine’s operating status and adjusts the cutting parameters or the program as necessary to cope with unforeseen situations or to optimize the machining results.
• Machining Completion: Once the machining task is complete, the operator removes the finished product and inspects it for quality. If the finished product meets the requirements, the machining process is finished; if not, further adjustments and machining may be required.

Different Types of CNC Machine Tools

CNC Milling Machines

CNC machining is a method that can be used to make any complex part. It uses a rotating cylindrical tool that cuts material from a solid block to create parts customized just for the user. The cutting tool on a CNC milling machine can move along more than one axis and rotate in the X, Y, and Z directions to mill the part. In short, CNC milling machines are the best way for many companies to manufacture high-quality, high-precision products.

CNC milling machines can translate specific commands so that the CNC can automatically control their movements. This is not possible with manual milling machines. If you use a manual milling machine, you may end up with a part that has a large margin of error. In addition, manual milling machines are difficult to use and slow to machine. This is because they need to be operated with the assistance of more than one person.

CNC Lathe

CNC lathes are mainly used to manufacture parts as per detailed design instructions. The material in the lathe tool clamps the spindle and rotates with it for machining metals, thermal spraying, and turning wood. CNC lathes can also produce flat, cylindrical, or conical shapes. They can also change surface roughness, weak groups, chamfer features, and the appearance of machined items.

CNC lathes make it easier to create precisely round products and reduce the chances of making mistakes by hand. Manual lathes can only produce prototypes by manually switching tools. Manual lathes can also be highly accurate but require more time and effort. When comparing a manual lathe to a CNC lathe, the CNC lathe is superior. This is because it works faster and is more accurate.

Electrical Discharge Machining (EDM)

EDM manufacturing is a machining process that uses heat to remove material from a workpiece. The machinist does not need to use mechanical force to complete the machining. EDM uses cutting tools mainly to fabricate and shape complex parts. It can also make industrial parts that cannot be made by milling machines or hand-operated machines.

EDM is the best and most efficient method of machining as compared to manual machining. Through this method, EDM machines can produce more accurate and higher-quality parts. The general advantages of this process make up for its partly high cost.

Components of a CNC Machine

• Controller: This is the core part of the CNC system and is responsible for receiving and executing the instructions in the computer program. The controller realizes precise machining operations by regulating the movements of the various components of the machine tool.
• Program Input Device: A device used to input or modify the CNC program. The operator can upload the program through the keyboard, USB port, or network to ensure that the machine performs the correct machining tasks.
• Axes: CNC machine tools typically have multiple axes, such as the X-, Y-, and Z-axes, each of which is responsible for motion in a specific direction. The combined motion of these axes determines the positioning and path of the tool relative to the workpiece.
• Drive System: This system consists of servo motors or stepper motors that are responsible for driving the movement of the machine’s axes. The drive system ensures smooth and precise movements of the machine tool for high-quality machining.
• Tool Spindle: The spindle drives the rotation of the tool and is the key component in performing the cutting operation. Its speed and accuracy directly affect the surface quality and efficiency of machining.
• Table: The workpiece is fixed on the table during machining. The table can move with the axes of the machine to match the tool to accomplish the desired machining path.
• Cutting Tools: These tools are in direct contact with the workpiece to perform operations such as cutting, drilling, and milling. Common cutting tools include milling cutters, turning tools, and drills.
• Coolant Systems: During machining, tools, and workpieces generate a lot of heat. A coolant system cools down the tool and workpiece by spraying coolant to prevent them from overheating, thus extending tool life and ensuring machining accuracy.

What Is Manual Machining?

Manual machining is a traditional manufacturing method in which an operator directly controls a machine tool to machine a workpiece. Unlike CNC machining, manual machining does not rely on a computer program; instead, the operator manually adjusts the various components of the machine tool to perform cutting, milling, drilling, and other operations. Although manual machining is not as accurate or efficient as CNC machining, it still has important applications in making one-off parts, prototyping, and small-volume production.

Manual machining usually requires experienced craftsmen who can manually operate machine tools to perform a variety of precision machining tasks depending on the requirements of the workpiece. Because there is no need to write a program, manual machining is more flexible when it comes to adjusting and switching production. Here are the two main types of manual machining currently available:

Manual Lathe Machining

Manual lathe machining is a type of machining that uses a manually controlled lathe to cut material. The workpiece of the lathe is usually rotationally symmetrical, and the operator manually controls the axial and radial movement of the tool along the workpiece to remove material and form the desired shape.

This type of machining is widely used to produce shafts, cylindrical parts such as bearings, threaded parts, and rings. The advantage of manual lathe machining is its flexibility, which makes it suitable for machining small batches or customized parts.

Manual Milling

Manual milling is a type of machining in which the milling operation is performed on a workpiece by manually controlling a milling machine. The milling process involves the tool rotating and moving along multiple axes to cut the desired shape. The operator controls the machining accuracy by manually adjusting the tool position and feed rate.

Manual milling is widely used to create flat surfaces, beveled surfaces, grooves, and complex contoured shapes. It is suitable for situations where quick adjustments or machining of single workpieces are required, and it is especially advantageous in small batch production and prototyping.

CNC machining Advantages & Disadvantages

Advantages of CNC Machining

Increased Production Speeds

Because CNC machines can run continuously and are optimized for cutting speeds, feed rates, and tool changes, they can significantly increase productivity. Especially when dealing with high-volume production tasks, CNC machining can manufacture a large number of parts in a short period.

Versatility and Consistency

One of the biggest advantages of CNC machining is its versatility and precision. CNC machining is used by many industries to manufacture parts. This is because it produces accurate parts, is efficient, and cuts consistently. Using CNC machines and technology, it is also possible to produce many different metals to order. CNC machining can be used to cut and manufacture a large number of parts at once. A skilled engineer can easily operate multiple CNC machines.

Less Staffing Needs and Less Maintenance Required

For manufacturing, CNC machines do not require many knowledgeable operators. In other words, production work can be done by only one skilled machinist. Even though CNC machines work all day long, they don’t require as much maintenance and upkeep as manual machines. They only need to be repaired at regular intervals.

Safety and Design Uniformity

One of the benefits of a CNC machine is that it can perform the same design over and over again. This is because some parts are measured and programmed the same way. This is a way to make more profit without increasing the workload or raising the charges. In addition, there is no risk associated with the use of CNC machines. This is because when CNC machining is performed, the operator is away from the machine and has no physical contact with it.

Versatility and Reduces Waste

CNC machines can perform a wide range of machining operations such as milling, drilling, turning, and cutting according to different program instructions. They are suitable for a wide range of materials and complex geometries, greatly expanding manufacturing capabilities and applications. In addition, material waste is minimized due to the high precision control of CNC machining. In addition, precise cutting paths and optimized machining parameters maximize material utilization and reduce costs.

Can Be Mass-produced with Low Labor Costs

CNC machining is particularly well suited to mass production tasks. One setup and programming is all it takes to automate production over long periods, dramatically increasing productivity and throughput. On the other hand, CNC machining is highly automated and typically requires minimal human intervention and supervision. This reduces the reliance on highly skilled operators, thereby lowering labor costs.

Disadvantages of CNC Machining

• High Initial Cost: CNC machines and associated software are expensive to purchase and install. In addition, specialized software and technicians are required to write CNC programs, which further increases the initial investment.
• Maintenance Costs: CNC machines require specialized personnel for maintenance and upkeep, and parts are expensive to replace and repair. If the equipment fails, it can lead to production stoppages and potential financial losses.
• Programming Complexity: CNC machining requires the writing of detailed programs, which requires an operator or engineer with programming skills. This complexity makes it potentially difficult for small businesses or start-ups to immediately adapt to CNC machining.
• Less Flexibility: While CNC machining performs well in mass production, it is not as flexible as manual machining when changing product designs frequently or producing small batches. Each time a production job is changed, the machine needs to be reprogrammed and reset, which can lead to increased time and costs.
• Energy Consumption: CNC machines typically consume more energy than manual machines, especially during long runs. This high energy consumption can increase operating costs, especially in areas with high electricity costs.
• Operator Skill Requirements: Although CNC machining reduces the reliance on manual operations, it requires operators to have a certain level of technical knowledge, such as programming, troubleshooting, and machine operation. This places a high demand on technical training.

Manual Machining Advantages & Disadvantages

Advantages of Manual Machining

• Flexibility for one-offs and prototypes: Manual machining is suitable for one-offs and prototypes because there is no need to write complex programs and the operator can work directly on the workpiece. This flexibility allows designs to be quickly adapted to meet customized needs.
• Lower cost for small production runs: Manual machining is often less expensive than CNC machining for small production runs. By eliminating the need for complex programming and setup, manual machining can produce small quantities of parts in a shorter period, saving time and money.
• Simplified Maintenance: Manual machines are relatively simple and easier to maintain. Required repairs can often be done by the operator or a regular mechanic, resulting in lower maintenance costs.
• Skill Development: Manual machining relies on the experience and skill of the operator, and long-term operation develops and improves the machining ability of the craftsman. This is beneficial for skill-building and craftsmanship.
• Immediate Adjustments: During manual machining, the operator can make immediate adjustments to the situation, such as changing the depth of cut, feed rate, or tool position. This ability to make immediate adjustments makes manual machining more flexible when responding to unexpected situations.
• Cost Effectiveness: Because manual machining does not require an expensive investment in equipment, the initial cost is low. Manual machining is an affordable option for small businesses or individual studios with limited capital.
• Short Turnaround Time: Manual machining allows production to start quickly because there is no complicated programming and setup time. Especially when emergency production or quick delivery is required, manual machining can provide shorter turnaround times.
• No Programming Required: Manual machining does not require CNC programming, eliminating the time and complexity of programming. For simple machining tasks or small production runs, manual operation is more straightforward and efficient.

Disadvantages of Manual Machining

• Lower Accuracy and Consistency: Manual machining relies on operator skill, so machining accuracy and consistency are lower than with CNC machining. Human error can lead to inconsistent part sizes, especially in high-volume production.
• Lower productivity: Manual machining typically takes longer than CNC machining, especially when working with complex or high-volume parts. The speed and skill of the operator determine productivity and therefore may not be sufficient for mass production.
• Operator Fatigue and Risk of Errors: Manual operations require long periods of concentration, which can lead to operator fatigue. Fatigue increases the risk of errors that can affect part quality and safety.
• Complex Shapes Limitations: Manual machines are limited in their ability to machine complex shapes and geometries, especially in multi-axis machining or operations that require precise linkages that are difficult to achieve with manual machines.
• Challenges with repetitive tasks: Manual machining is difficult for tasks that require a high degree of repeatability and consistency. Even experienced operators struggle to maintain a high level of consistency from part to part over long periods.
• High Labor Requirements: Manual machining relies on operator skill and experience, and therefore requires a high level of craftsmanship. This increases training and labor costs and can impact production when operators are unavailable or there are labor shortages.
• Higher Safety Risks: Manual machining involves more direct operator contact with the machine tool, increasing the risk of injury. Without automated safety guards, operator safety relies on individual attention and experience.

Application Comparison

CNC Machining vs. Manual Machining: Key Differences Explained

CNC machining and manual machining are two common types of machining in the manufacturing industry, each with its own unique advantages and limitations. To better understand the differences between them, we can compare them in terms of accuracy, repeatability, production volume, skills required, training, and initial cost. Below is a comparison table that Yonglihao Machinery has put together to help you quickly understand the differences between these two machining methods.

What Is the Difference in Price Between CNC and Manual Machining?

You will see the price differences between CNC and manual machining in this section. The main price differences are listed below:

The Overall Cost of CNC Machining Is Lower than Manual Machining

The cost of machining depends on many things. Such as how much scrap is made, labor costs, maintenance costs, and how many parts are made in total. When you make an in-depth comparison between CNC machining and manual machining, you may find that CNC machining is less expensive in the long run.

Low Scrap and Maintenance Issues

In terms of production, CNC machining is more accurate and precise. And because there are fewer scrapes, CNC machining is cheaper. Whereas manual machining has higher labor and maintenance costs, which limits its use and makes it more costly.

Increased Industrial Demand

Manual machining is a bit more expensive because this type of machining has a higher scrap rate, high labor costs, and requires more maintenance. The demand for CNC machined parts is increasing all over the world because the parts are more accurate and have a lower scrap rate.

Considerations for CNC Machining

Initial Investment and Maintenance Costs: CNC machine tools have a high initial investment and usually require a large budget for the purchase of the machine tool, programming software, as well as installation and infrastructure modifications. In addition, the maintenance costs of CNC machine tools should not be ignored. Regular professional maintenance is the key to ensuring a long life and efficient operation of the machine tool, and failure to maintain it promptly may result in downtime and high repair costs. Therefore, companies should give full consideration to full life cycle costs when choosing CNC machining.

Skilled Programmers: The success of CNC machining relies on high-quality programming, so experienced programmers are needed. Programming errors can lead to scrap parts or damage to the machine tool, so ensuring programmers are skilled and trained is critical. Companies should invest resources in technical training and regularly check the quality of programs to ensure accuracy and efficiency in production.

Summary

There is a big difference between CNC machining and manual machining. CNC machining is faster and more accurate than manual machining. You cannot expect the same results from manual machining as you can from CNC machining.

CNC machining is controlled by CAD and CAM software, which is more accurate, precise, and safe. CNC machining is faster, produces a better product, costs less, and is safer than manual machining.

No longer using manual machining to prototype parts? You can utilize Yonglihao Machinery’s unique CNC machining services. In addition, you can get instant quotes for CNC machining and custom-machined parts on our website. You can also get free DFM feedback and a full-dimensional report for review. Contact us and send us your files for instant pricing!

Continue reading: CNC Machining Vs SLS 3D Printing

FAQ

How Can I Tell the Difference between a CNC Lathe and a Manual Lathe?

In terms of precision and time, manual lathes are inferior to CNC machines. With careful cutting, manual lathes can provide you with high precision. However, CNC lathes can produce more accurate parts in less time and at a lower cost. CNC lathes are easy to use and require no experience to perform difficult machining. In contrast, machining with a manual lathe requires extensive experience.

What Are the Disadvantages of CNC Machining?

Although there are many advantages to CNC machining, there are also some disadvantages. Although CNC machines were once more expensive than conventional machines, the cost of running CNC machines is slowly coming down. And using CNC machining does not require any special skills or information. This means that we are losing people with skills and knowledge. For CNC machining, the amount of work required will also be reduced, which may lead to unemployment and brain drain in the engineering field.

Which Manufacturing Method Is Safer?

Manual machines must be touched and operated to make them work. Some manual machines can be more dangerous to use. CNC tools, on the other hand, are automated so you don’t have to touch them. They are not near workers and the work takes place in a safe room or behind a safe door. This shows that CNC machining is safer and more efficient than manual machining.

Is CNC machining suitable for a wide range of materials and applications?

CNC machining is suitable for a wide range of materials, such as metals, plastics, and composites, and is capable of performing a wide range of machining tasks for a variety of industrial applications.

Is CNC more accurate than manual machining?

Yes, CNC machining is computerized to ensure high accuracy and consistency and is often more precise than manual machining, especially in the machining of complex parts.