If you are deliberating whether to invest in CNC machining over manual machining, then this article is for you.
This article compares these two manufacturing techniques, outlining their working principles, advantages, drawbacks and key differences. Thus helping you to make the best decision for the production of your prototypes and final parts.
What is CNC Machining?
CNC machining is a subtractive manufacturing method that uses computerized machine tools to remove material from a workpiece to achieve parts with precise and exact dimensions. In CNC machining, programmers generate codes from a computer-aided design (CAD) model of the desired geometry, which are used to control the machine’s actions.
The first step in CNC machining is to create a 2D or 3D CAD model of the desired part. Then you convert it to G-code which the machine can understand with the use of a computer-aided manufacturing (CAM) software. Afterward, you set up the machine and workpiece, and finally start the machining process.
Because this whole process is automated, you are assured of precise and accurate machined parts with tight tolerances. There is also little to no room for human error, which gives it a significant advantage over manual machining.
What is Manual Machining?
Manual machining as the name implies is done with the use of hands. It’s the manual removal of excess material from a workpiece by a skilled operator to form the desired shape. These operators handle tools like manually operated end mills, bandsaws, grinders, and lathes. They are also in charge of controlling the speed, feed rate, and cut depth as the tool requires adjustments occasionally.
In manual machining, the skilled machinist places the workpiece on the milling machine table and selects the work tool based on the intended operation. Using the various manual controls on the tool such as levers or handwheels, the operator skillfully cuts through the workpiece to remove excess material. This action forms the desired shape along the line. You can use manual machining for simpler designs or DIY crafts that do not require high precision.
Pros and Cons of CNC Machining and Manual Machining
All manufacturing processes have their benefits as well as disadvantages across the volume of production, precision, accuracy, and cost. Here are the benefits and disadvantages of manual vs CNC machining
Pros of CNC Machining
- CNC machining ensures parts are produced faster and in large quantities.
- Repeating the same task more than once can lead to human error, and CNC machining eliminates that.
- It requires a limited number of skilled operators familiar with CNC machines to handle production.
- It is useful in producing complex and intricate designs and geometries..
Cons of CNC Machining
- CNC machining equipment and installation costs are way higher
- Only an expert can fix the machine when it breaks down, although it rarely occurs.
- Because of its numerical codes, it requires the skills of a programmer to build and set up the codes needed for the machines to operate.
Pros of Manual Machining
- You can get and install manual machining equipment at a lower cost.
- Since it is operated with hands by skilled operators, there’s no need for advanced programming or building and setting up of code.
- Manual machines are easy to repair when they become faulty.
Cons of Manual Machining
- Manual machining is a slow method for manufacturing parts, which means it can’t be used for mass production without increasing labor and equipment costs.
- The chances of human error are high since manual machines don’t major in precision.
- The production of parts is dependent on the level of expertise of the operator. And this may increase labor costs.
Differences Between CNC Vs. Manual Machining
While CNC machining and manual machining aim to achieve the same result, the way it is being carried out and the quality of the end product are quite different. Here are the main differences between CNC machining vs. manual machining:
Accuracy
Accuracy refers to how the produced part meets the design specification in the CNC file. In the CNC machining industry, accuracy is an important feature. Its use of computer-controlled movements makes it very precise in production, thereby eliminating human error. There’s no doubt that when using CNC machines for manufacturing, you will get accurate and precise results as they follow the exact instructions you programmed.
On the other hand, achieving accuracy and precision in manual machining depends solely on the skills and expertise of the operator. Although you can get accuracy from a skilled machinist, it is prone to human error since it is done by hand, making it difficult to maintain quality.
Repeatability
Repeatability entails doing a certain task multiple times. In this industry, it means producing the same product more than once and achieving the exact results. This is the great selling point of CNC machining, which makes for its popularity among huge sectors. CNC machines strictly follow what you have programmed into their system and carry out the instructions, producing the same product to the number required. This shows the repeatability feature of CNC machining.
In comparison, manual machining has a lower capability to achieve repeatability. This is due to the huge dependence on the operator’s skills. Although a very good and skillful operator can achieve repeatability, it has more chances of producing parts with variations because of human constraints.
Production Volume
CNC machining is used for manufacturing many parts. This is because CNC machining is an automated process, which makes it easy to have mass production without compromising quality. As soon as you have programmed the instructions into the CNC machines, it can produce a large number of identical parts. This is accomplished with limited human intervention. This can only mean that CNC machining is the best option for industries that need high-volume production along with efficiency and high consistency.
However, Manual machining is functional for low-production volume. Although it still maintains flexibility and versatility, its hands-on feature makes the method time-consuming for high-volume production.
Skills Required
The skills required for CNC machining differ greatly from manual machining. Before the CNC machine becomes operational, it requires the operator to possess knowledge of the following; Computer programming, CAD design, CAM software, G-code, and the control panel of the CNC machine. A CNC machinist must be able to program the machine, read the design directions, and sort out any issues before the automated process begins.
On the other hand, manual machining relies majorly on the skills and expertise of the operator. The operator must have a wealth of knowledge on cutting tools, different materials, and various machining techniques to operate manual machines. The important skills the operator must possess include being able to interpret technical designs, choose the correct tools required for a particular task, set up a machine, and control it by hand.
Here’s a table showing the difference between CNC machining vs Manual machining:
| Category | CNC machining | Manual machining |
| Accuracy | It’s more accurate and precise in the production of parts. | Depends on the skills of the operator, and it’s more prone to human error. |
| Repeatability | It has a higher chance of achieving repeatability without compromising the parts’ quality. | It has a lower capability of achieving repeatability. |
| Production volume | Suitable for high-volume production | Suitable for low-volume production. |
| Skills required | Programming, CAD design, CAM software, and the CNC machine control panel. | Interpret technical designs, ability to select and operate the right tool. |
Factors Affecting the Cost of CNC Vs. Manual Machining
Although CNC machining costs way higher than manual machining, various factors affect the cost of both machining methods. Here are some major factors affecting the cost of CNC and manual machining:
Labor
CNC machining has a lower labor cost compared to manual machining. This is possible due to its higher automation features, which require minimal human intervention. While manual machining has a higher labor cost due to the level of expertise required. Since the machine is being operated by hand, there’s a need to hire quite a number of skilled operators.
Programming
Programming cost is only attributable to CNC machining, as advanced technologies require coding skills to run the machine operations. However, manual machining does not require programming skills, thereby reducing its overall cost.
Waste Product
Lower waste product doesn’t only mean reduced cost but also means there’s less chance for your customers to reject the final products. The waste product during the CNC machining process is less, which will help during mass production, as customers will find it difficult to receive faulty parts. However, manual machining has more material waste due to its method of manufacturing parts.
Maintenance Issues
CNC machining can detect issues in its system, but the maintenance cost is way higher due to its complexity. Although manual machining has multiple tool breakdown issues, fixing it and maintaining it costs less than CNC machining.
Applications of Manual Machining vs. CNC Machining?
CNC and manual machining have different applications, varying in the types of tasks and the level of precision required. Here are their applications:
Applications of CNC Machining
Industrial Uses
CNC machining is popular across several industries. It is used mostly in industries like aerospace, defense, and automotive that require high-volume production. A good example is the automotive industry requiring CNC mills and lathes for the production of its engine parts and transmissions. Using manual machining in this scenario will only slow down production and cause each part to vary.
Prototyping Tasks
CNC machining is the most preferred option for rapid prototyping when you are in the product development phase. You can create prototypes that are similar to what the end product should look like with CNC mills, lathes, and other needed machines. This helps you test the functionality of the design before you proceed with producing en-mass.
Rapid Tooling Applications
CNC machining is the best option for rapid tooling when you want to work on tough materials and CNC alloys. Manual machining can be difficult when using it on hard materials.
Applications of Manual Machining
Small-Scale Projects
Manual machines such as mills, manual lathes and other manually operated cutting tools are more efficient for small or one-off tasks. This is because manual machines are faster to set up and do not need complex programming.
Personal Craftsmanship and Artistic Metalwork
Manual machining process is one method that encourages personal craftsmanship instead of mass production. Manual machining is best used in artistic metal work or personal crafts, in which both tasks will require the skills of an operator, where workpieces and cutting tools are hand-picked to perform certain operations.
Repair and Maintenance
When older machinery develops faults, where the parts needed for repair are unavailable, manual machining is seen as the go-to solution. It allows for the custom fabrication of parts needed for repairs.
Prototyping and Customization
Manual machining is mostly used for prototyping tasks where you have small quantities of components that need to be custom-fabricated immediately at a reduced cost. A skilled operator can use any manual tools ranging from drills, and mills to lathes to build prototypes according to the requirements laid down by the client, giving room for adjustment and rapid iteration.
CNC Vs. Manual Machining: Which One is Suitable for Your Needs?
Deciding on which machining method to use, CNC or manual, majorly depends on your manufacturing goals and requirements. As you know the difference between both machining techniques, it will make it easier to decide according to your goals.
If you need a method that can help you achieve precision, accuracy, and complex geometry and produce the same product in multiples, CNC machining is your best choice. On the other hand, if you need a technique for a one-off customized project, manual machining should be your go-to solution.
Before you decide on the method to use for your project, it is important to also factor in your budget in the final decision. Budget can be a critical constraint for your project, so if you have a limited budget for production, maybe for small-scale production, you should go for manual machining. But if it is a large-scale production with an open budget, you can opt for CNC machining.
Overall, before choosing the suitable option for your project, you should consider the project requirements, budget, and desired final product. These three main factors will help shape your decision.
Conclusion
Now that you understand the differences between CNC machining vs Manual machining, you can see the benefits of using CNC machining for your machined parts.
With over 10 years of experience, JIEJIA CNC offers a wide range of machining services to meet your needs. Contact us today for your CNC machining needs.
FAQs
1. What are the disadvantages of CNC machines over manual machines?
CNC machines can be expensive to purchase and maintain. They also require technical knowledge and programming skills, which can be a barrier for some. Additionally, they can be less flexible for small, simple jobs compared to manual machines, which are more adaptable and quick to set up for certain tasks.
2. Is a CNC machinist the same as a manual machinist?
No, a CNC machinist specializes in operating computer-controlled machines that require programming and precise setup. A manual machinist works with traditional, non-computerized equipment, requiring hands-on control to shape and finish parts. While both require machining skills, CNC machinists work with more automated systems.
3. How long can a CNC machine last?
A CNC machine can last anywhere from 10 to 25 years, depending on usage, maintenance, and the quality of the machine. Regular maintenance and proper care can extend the life of the machine and ensure optimal performance over the years.
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