What Are CNC Turned Parts and Why Are They Critical?
CNC turned parts are the components produced by a process called CNC turning. The CNC turning method is a process where the material is trimmed off from a spinning cylindrical or rod-shaped workpiece. The cutting tool reciprocates against the workpiece to form it.
The operation of the cutting machine is controlled by a computer. CNC is short for Computer Numerical Control. This computer control ensures that every part is made in a very exact manner. Each component is like a mirror image of the previously produced one. This high repeatability is a critical factor in today’s production processes.
CNC turned parts are characterized by the following main points:
- Generally circular or conical in shape
- Very high accuracy and extremely tight tolerances
- Smooth surface finishes
- Can be used for prototyping or manufacturing both single and mass produced parts
- Suitable for making customized parts
These are components used in innumerable things. They are found in places such as vehicles and aircraft. They can also be found in medical tools and electronic devices. These parts are at the core of production in today’s manufacturing.
The CNC Turning Process: From Raw Material to Finished Part
Gaining a better insight into part production is a great asset for being able to design more effectively. The CNC turning process, which converts a raw bar of material into a finished part, includes the following sequentially outlined activities.
Here are the steps to CNC turned parts creation:
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Design and Programming: The first step is making a 3D CAD model. CAD stands for Computer-Aided Design. This electronic blueprint is converted into machine-specific instructions, called G-code, which are for the CNC machine. The code describes the movements the CNC machine must make.
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Machine Setup: A trained professional sets the CNC lathe. The raw material that is commonly used here is a long bar made of either plastic or metal. Spinning it will cause the object to get clamped in the machine’s chuck. The required cutting tools are arranged in the machine’s turret.
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The Turning Operation: The device is started to rotate the workpiece at a high speed. The tool presents the G-code instructions. It is advancing on the workpiece in two axes. The material is taken off with precision to obtain the elements of the part, such as the steps, grooves, and threads.
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Secondary Operations: Present-day CNC turning centers are multifunctional. They are turned, yes, but also “live tooling” capable. This means that they can drill and cut flat surfaces. They can create features without having to move the part to other machines. That is a tremendous time-saver and ensures higher precision.
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Finition et inspection : After machining, the part is cut from the bar stock. Often, it is deburred to eliminate burrs. An anodizing or plating surface finish may be applied to it. As a final check, all dimensions are verified with precision measuring instruments. Thus, it is assured that the part meets the quality technical standards of the design.
Common Materials and Finishes for CNC Turned Parts
Choosing the right material is one of the most important decisions of a project. The material will affect not only the strength, weight, and corrosion resistance of the part but also its cost. CNC turning can effectively work with a wide range of materials including metals and plastics.
The following table summarizes the most common materials for CNC turned parts and their applications.
| Matériau | Propriétés principales | Common Applications for CNC Turned Parts |
|---|---|---|
| Métaux | ||
| Aluminium (6061, 7075) | Low weight, high strength-to-weight ratio, resistant to rust | Aerospace fittings, electronic housings, consumer products |
| Stainless Steel (303, 304, 316) | High stiffness, excellent rust resistance, heat resistant | Medical devices, food-grade parts, marine hardware |
| Laiton | Low friction, easy to process, and anti-rust | Plumbing fittings, electrical connectors, decorative parts |
| Titane | The best strength-to-weight ratio, body-safe, and extremely rust-resistant | Aerospace parts, medical implants, high-performance sports equipment |
| Plastiques | ||
| Delrin (POM) | High rigidity, low friction, and holds the shape well | Bearings, gears, and fuel system parts |
| PEEK | Pitch-high performance, included strength, and chemical resistance at high heat | Medical implants, and aerospace and semiconductor parts |
When a part is machined, it often needs a surface finish. It can serve the purpose of protective covering, or improving aesthetics. The primary finishes of turned components include as-machined, bead blasting, and anodizing for aluminum. Besides them, there are nickel or chrome plating and polishing finishes as well.
A Practical Guide to Sourcing CNC Turned Parts
We have successfully produced millions of parts and so, through our trials and errors, we present to you the stepwise procedure that will guarantee the profitability of your project. It is not just through finding a supplier that the fabrication of the turn parts. But it takes a smart design-clear communication and careful evaluation.
Step 1: Design for Manufacturability (DFM)
The term Design for Manufacturability refers to the process of part design that is easy and cost-effective to produce. For turned parts, this method can be achieved through some main principles.
Have a try to simply the part shape. Use standard sizes for holes and threads when it is possible. Avoid extremely tight tolerances unless indeed necessary for the part to work. This concerns the cost of manufacturing significantly. Also, consider the way the part will be held in the machine during the turning operation.
Step 2: Creating a Complete Request for Quote (RFQ)
To receive accurate and fast quotes you have to provide complete information to possible suppliers. A clear RFQ prevents misunderstandings and delays in the process.
Your RFQ for CNC turned parts should always include:
- 3D CAD files (STEP format is the best)
- 2D technical drawings that show all dimensions and tolerances clearly
- The specific material needed (e.g. Aluminum 6061-T6)
- The quantities you need (e.g. 10, 100, and 1000 pieces)
- Any suitable surface finish or secondary operations required
Step 3: Evaluating a Supplier and Ensuring Quality
The right manufacturing partner is the key. The supplier should be the one with a proven history of quality. Ask for their certifications. ISO 9001 indicates a supportive quality management system.
You must ask about their machine capabilities and if they have any quality control processes. Do they have advanced tools like a CMM for inspection? CMM stands for Co-ordinate Measuring Machine. Besides, communication is an asset. A reliable partner will employ the necessary procedures for quality and precision in CNC turned components.
For more information about our services, feel free to check our Service de tournage CNC.
Cost Drivers for CNC Turned Parts: An Insider’s Breakdown
Understanding the things that impact the cost of CNC turned parts is the very first step to budgeting your project well. Several elements play a role in determining the final price of each part.
Here’s an overview of the main cost drivers:
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Material Cost: The choice of raw material is a significant contributor. Some materials like Aluminum 6061 are much cheaper compared to rare alloys. While titanium and high-performance plastics like PEEK come at an increased cost.
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Complexité des pièces : The number of features a part has is in direct relation to the time it will take to machine it. Complex curves, thin walls, and very intricate details are the key points that make machine running time longer leading to cost increase.
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Tolérances : Experiencing very tight tolerances needs more attention and slower cutting/speeds. More inspection time leads to more work as well. A change from standard tolerance +/- 0.005″ to very tight tolerance +/- 0.0005″ can make the cost rise substantially.
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Cycle Time: This is the total amount of time that it takes to produce one unit. Longer cycle times translate into high costs.
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Labor & Setup: This is the one-time cost of programming the machine and preparing it for a specific job. This cost is distributed across all the parts in the order.
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Quantity: The cost of the parts is reduced with quantity increases. This is attributed to the setup cost being spread over a larger amount of parts.
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Finishing & Secondary Ops: Every additional processing step adds cost to the final product. For instance, anodizing, heat treatment, or assembly.
CNC Turning vs. Other Machining Processes
CNC turning is an excellent procedure; however, it is not appropriate in all situations. Being able to choose when to use a lathe compared to other procedures like milling or drilling can save you both time and money.
CNC Turning vs. CNC Milling
The critical element that is different is the motion of the machines. For instance, the part is moved in CNC turning while the tool remains still. In CNC milling, however, the part is held stationary while the tool rotates in order to take off material.
- Use Turning For: Round parts, shafts, pins, fasteners, and other components with a round profile.
- Use Milling For: Square or block-shaped parts, complex surfaces, and parts with features on multiple faces.
Standard CNC Turning vs. Swiss Turning
Swiss turning is a specific type of CNC turning, with characteristics designed for very small, long, and slender parts to be produced with high accuracy. The machine supports the workpiece very close to the cutting tool, thus eliminating bending.
This is also a vital skill for producing elaborate parts. Our Services de tournage CNC suisse will tell you all about it. The decision on the process is really the most important one for the manufacturers of Precision CNC turned parts for various industries.
Let’s Build Your Next Project Together
CNC turned parts are the ideal, adaptable, precise and scalable choice for creating critical components. The choice of material and design optimization is largely instrumental to the success of the project. Equally, working with a proficient manufacturing partner is paramount.
Excited to get started? Contact Mékalite today and our engineers will be happy to discuss your project with you.
Frequently Asked Questions (FAQ) About CNC Turned Parts
What is the typical tolerance that CNC turning can achieve?
The standard tolerances for CNC turning are normally about +/- 0.005 inches (0.127 mm). Using high-precision equipment along with a controlled process, a much tighter tolerance can be achieved. The tolerances of +/- 0.0002 inches (0.005 mm) are possible in critical features. However, this increases the cost and is recommended to be specified only when necessary.
What is the difference between a CNC lathe and a CNC turning center?
These terms are mostly used as synonyms. A traditional lathe as it is primarily thought of is only a turning machine. A turning center is an evolved machine that can do more than that by turning and doing operations like milling, drilling, and tapping in a single setup. This process is the more straightforward way of fabricating complex parts.
Can you create square or hexagonal features on a CNC turned part?
Yes, they can. While the primary operation forms cylindrical parts, modern CNC turning machines can be fitted with ‘live tooling’ axes. These, in-turn, are rotating tools that can mill operations. Wrenches for instance, can be made to have flats and hex shapes. They can also be used to create cross-drilled holes and other non-round features on the parts.
What is the ideal quantity for CNC turning?
CNC turning is a versatile process. It’s profitable for single prototypes and it also performs well in low-to-mid volume production runs in the hundreds and thousands of parts. Turning with automation such as bar feeders can also be very efficient for high volume production of tens of thousands of CNC turned components.
What file formats are needed to get a quote for CNC turned parts?
The most important file is a 3D CAD model. This is usually in a universal format like STEP or IGS. It is also highly recommended to provide a 2D PDF drawing. The drawing should specify all critical dimensions, tolerances, materials, and any surface finish requirements. This ensures an accurate quote.
