CNC milling is a highly precise manufacturing process used to create a wide range of parts with complex geometries. However, the journey of a CNC – milled part doesn’t end once it comes off the milling machine. Post – processing steps are crucial to ensure the final product meets the required specifications, quality standards, and functionality. As a supplier of CNC milling parts, I’d like to share some of the key post – processing steps that we commonly perform. Фрезерные детали с ЧПУ
1. Deburring
One of the first and most important post – processing steps is deburring. During the CNC milling process, sharp edges and burrs are often left on the part. These burrs can be a result of the cutting tool’s action, such as the shearing of the material or the interaction between the tool and the workpiece.
Burrs can cause several problems. They can interfere with the proper assembly of the part, as they may prevent components from fitting together correctly. In addition, sharp burrs can pose a safety hazard to those handling the parts. For example, in industries where workers need to handle parts manually, burrs can cause cuts and abrasions.
There are several methods for deburring CNC – milled parts. Manual deburring is a common approach, where operators use hand tools such as files, sandpaper, or deburring knives to remove the burrs. This method is suitable for small – batch production or parts with complex geometries where automated methods may not be effective.
Automated deburring methods are also widely used, especially for high – volume production. These methods include tumbling, where parts are placed in a tumbling barrel with abrasive media. The movement of the barrel causes the abrasive media to rub against the parts, removing the burrs. Another automated method is abrasive blasting, where abrasive particles are propelled at high speed onto the part surface using compressed air or a water jet.
2. Surface Finishing
Surface finishing is another critical post – processing step. The surface finish of a CNC – milled part can affect its appearance, corrosion resistance, and functionality. There are various surface finishing techniques available, and the choice depends on the specific requirements of the part.
Polishing
Polishing is a process used to create a smooth and shiny surface. It involves using abrasive materials of progressively finer grits to remove surface irregularities and create a mirror – like finish. Polishing is often required for parts that are visible in the final product, such as consumer electronics or automotive components. It can also improve the corrosion resistance of the part by reducing the surface area exposed to the environment.
Grinding
Grinding is a more aggressive surface finishing process compared to polishing. It is used to remove a larger amount of material and achieve a high – precision surface finish. Grinding is commonly used for parts that require tight tolerances, such as bearings or shafts. In the grinding process, a rotating grinding wheel with abrasive particles is used to cut and shape the surface of the part.
Anodizing
Anodizing is an electrochemical process used to create a protective oxide layer on the surface of aluminum and other non – ferrous metals. This oxide layer can improve the part’s corrosion resistance, wear resistance, and appearance. Anodizing can also provide a base for painting or other surface coatings. In the anodizing process, the part is immersed in an electrolyte solution and an electric current is passed through it, causing the formation of an oxide layer on the surface.
Powder Coating
Powder coating is a dry finishing process that involves applying a fine powder to the surface of the part. The powder is electrostatically charged, which causes it to adhere to the part. The part is then heated in an oven, causing the powder to melt and form a durable, smooth coating. Powder coating provides excellent corrosion resistance, durability, and a wide range of color options. It is commonly used for outdoor equipment, furniture, and automotive parts.
3. Heat Treatment
Heat treatment is a post – processing step used to alter the physical and mechanical properties of the CNC – milled part. It can improve the part’s hardness, strength, toughness, and wear resistance. There are several types of heat treatment processes, and the choice depends on the material of the part and the desired properties.
Annealing
Annealing is a heat treatment process used to soften the material and relieve internal stresses. It involves heating the part to a specific temperature and then slowly cooling it. Annealing is often used for metals that have been cold – worked during the CNC milling process, such as steel or copper. By annealing the part, its ductility is increased, making it easier to machine or form in subsequent operations.
Quenching and Tempering
Quenching and tempering are two – step heat treatment processes commonly used for steel parts. Quenching involves heating the part to a high temperature and then rapidly cooling it in a quenching medium, such as oil or water. This rapid cooling hardens the steel but also makes it brittle. Tempering is then performed to reduce the brittleness and improve the toughness of the part. It involves reheating the quenched part to a lower temperature and then cooling it slowly.
Case Hardening
Case hardening is a heat treatment process used to create a hard surface layer on the part while maintaining a tough and ductile core. This is particularly useful for parts that require high wear resistance on the surface, such as gears or shafts. Case hardening can be achieved through methods such as carburizing, nitriding, or carbonitriding. In carburizing, the part is heated in a carbon – rich environment, allowing carbon to diffuse into the surface layer. Nitriding involves introducing nitrogen into the surface layer of the part, while carbonitriding combines both carbon and nitrogen diffusion.
4. Inspection and Quality Control
After all the post – processing steps are completed, it is essential to perform a comprehensive inspection and quality control of the CNC – milled parts. This ensures that the parts meet the required specifications and quality standards.
Dimensional Inspection
Dimensional inspection is used to verify that the part’s dimensions are within the specified tolerance. This can be done using various measuring tools, such as calipers, micrometers, coordinate measuring machines (CMMs), and optical measuring systems. CMMs are particularly accurate and can measure complex geometries with high precision. They use a probe to touch the surface of the part at multiple points, and the data is then analyzed to determine if the part meets the design requirements.
Surface Inspection
Surface inspection is used to check the surface finish and detect any defects, such as cracks, pores, or scratches. Visual inspection is a simple and common method, where operators use their eyes or magnifying glasses to examine the part surface. More advanced techniques, such as ultrasonic testing, magnetic particle testing, and dye penetrant testing, can be used to detect hidden defects that are not visible to the naked eye.
Material Testing
Material testing is used to verify the material properties of the part, such as hardness, strength, and composition. Hardness testing can be done using methods such as Rockwell hardness testing, Brinell hardness testing, or Vickers hardness testing. These tests involve applying a specific load to a small indentor on the part surface and measuring the size of the indentation. Chemical analysis can also be performed to determine the material composition and ensure that it meets the specified requirements.
5. Packaging and Shipping
Once the parts have passed the inspection and quality control, the final step is packaging and shipping. Proper packaging is essential to protect the parts during transportation and storage. The packaging should be designed to prevent damage from vibration, shock, moisture, and corrosion.
For small parts, they can be placed in plastic bags or boxes with protective padding, such as foam or bubble wrap. Larger parts may require custom – made crates or pallets for packaging. The packaging should also include labels with information such as the part number, quantity, and handling instructions.
When it comes to shipping, we work with reliable logistics partners to ensure that the parts are delivered to our customers in a timely and safe manner. We offer various shipping options, including express shipping for urgent orders and standard shipping for less time – sensitive deliveries.
tungsten carbide parts As a supplier of CNC milling parts, we understand the importance of these post – processing steps in ensuring the quality and functionality of our products. By following these steps carefully, we can provide our customers with high – quality parts that meet their specific requirements. If you are in need of CNC milling parts and would like to discuss your procurement needs, please feel free to reach out to us. We are committed to providing excellent products and services to our customers.
References
- ASM Handbook Volume 4: Heat Treating
- Machinery’s Handbook, 31st Edition
- ISO 2768: Geometrical Product Specifications (GPS) – General tolerances for linear and angular dimensions without individual tolerance indications
000 Redex Part
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