What are the dimensional accuracy and surface quality requirements for Copper Casting Parts?

The dimensional accuracy and surface quality of Copper Casting Parts are key factors affecting their performance and scope of application. In the production process, the requirements for dimensional accuracy and surface quality are not only directly related to the use effect of copper castings, but also determine whether they can meet the standards and customer needs of specific industries. The following are detailed requirements and control methods for dimensional accuracy and surface quality of copper castings:

Dimensional accuracy requirements for copper castings
The dimensional accuracy of copper castings refers to the difference between the casting size and the design size. In order to ensure that copper castings can meet the requirements of installation and use, the dimensional accuracy is usually controlled within a certain tolerance range. The dimensional accuracy of copper castings is affected by many factors, including casting process, casting materials, mold design, pouring temperature, etc.

Dimensional accuracy grade:
Dimensional accuracy of copper castings Grades can usually be divided into several levels, such as rough accuracy, ordinary accuracy and high accuracy.
Rough accuracy is suitable for some castings with low dimensional requirements, usually above ±2mm.
Ordinary accuracy is suitable for most copper castings, usually controlled within the range of ±1mm.
High-precision castings require smaller dimensional tolerances, usually controlled within ±0.5mm, and even castings with higher precision requirements can reach ±0.1mm.
Factors affecting dimensional accuracy:
Casting shrinkage: Copper will undergo thermal expansion and cooling shrinkage during the casting process, and the amount of shrinkage is an important factor affecting dimensional accuracy. In order to compensate for the shrinkage of the casting, the size of the casting is usually compensated accordingly during design.

Mold design: The design of the mold directly affects the dimensional accuracy of the casting. Mold precision requirements and quality , determines whether the size of the casting is accurate. If the mold is not made accurately, it will cause dimensional deviation of the casting.
Pouring temperature and cooling rate: During the casting process, the temperature and cooling rate of the copper liquid affect the shrinkage rate and shape stability of the copper casting. Too fast or too slow cooling may cause deformation or dimensional deviation.
Dimension measurement and control methods:
During the casting process, the size can be inspected by using precision measuring equipment such as three-dimensional coordinate measuring machine (CMM) to ensure that the size of each copper casting meets the design requirements.
For castings with smaller sizes or higher precision requirements, three-dimensional measurement using laser scanning technology is also a common method.
Process control and regular inspections are carried out during the casting process to adjust the mold and process parameters to ensure the size of the product throughout the production process. Stable.
Surface quality requirements of copper castings
The surface quality of copper castings refers to the smoothness, flatness, and number and type of defects on the surface of the castings. Good surface quality can not only improve the beauty of the castings, but also improve their corrosion resistance, wear resistance, and convenience of subsequent processing.
Types of surface defects:
Porosity: Porosity is a common defect on the surface of copper castings, usually caused by the failure of gas to be discharged during the pouring process or the presence of gas in the copper liquid. The presence of pores will affect the strength and sealing of the castings.
Cracks: Copper castings may crack due to excessive thermal stress during the cooling process. Cracks not only affect the appearance, but also affect the mechanical properties of the castings.
Sand holes: Sand holes are defects on the surface of the castings caused by the failure of sand particles in the sand mold to completely fall off, usually manifested as surface depressions.
Surface roughness: Surface roughness is an important indicator of castings, which refers to the degree of tiny unevenness on the surface of the castings. Excessive surface roughness may affect the performance of the castings, especially on parts that require good fit or sealing.
Bubbles and sand marks: Bubbles are depressions on the surface of castings due to the inability of molten metal gas to be discharged, and sand marks are scratches on the surface of castings due to the rough surface of the casting or incomplete demolding.
Surface quality control requirements:
Surface finish: The surface finish requirements of copper castings are usually determined according to the needs of specific applications. If the casting requires higher aesthetics and corrosion resistance, the surface finish usually needs to reach Ra 3.26.3μm (roughness). For precision castings or decorative castings, the finish requirement can reach Ra 0.81.6μm.
Cleanliness: The surface of the casting must be clean and free of impurities, and no excess substances generated during the casting process. The castings after sand casting need to remove residual sand particles and clean the surface dirt.
No defects: The surface of copper castings should avoid defects such as pores, cracks, and sand holes as much as possible. Especially for copper castings that require high strength and corrosion resistance, surface defects must be strictly controlled to avoid affecting the performance.

The dimensional accuracy and surface quality of copper castings are key factors affecting their performance and applicability. In order to ensure that copper castings can meet various application requirements, the dimensional accuracy and surface quality need to be strictly controlled during the casting process. By reasonably selecting the casting process and optimizing the mold design, the dimensional accuracy and surface quality of copper castings can be effectively improved to ensure their stability and reliability in various complex environments.