Manufacturing Accuracy Precision Parts

Precision parts are manufactured by CNC machines, but we need to pay attention to parts accuracy. understanding the process technology.

For example, process precision auto parts mainly pay attention to dimensional accuracy, shape accuracy, position accuracy, and surface quality. The tolerance range is usually at the micron level or even smaller, the tolerance according to customer special requirements, and usually marked on the drawing.

MK CNC processing precision parts dimensional accuracy according to the customer’s special requirements.
The precision auto parts dimensional accuracy requirements are extremely high. The dimensions are usually controlled at IT5 to IT7 levels, but some customer request parts reach the IT6 level in special cases. For example, the dimensional tolerance range of engine parts, such as crankshafts, connecting rods, valves, cylinder blocks, etc. the tolerance generally between ±0.01mm and ±0.001mm.
For high-speed moving parts, such as the piston connecting rod group of a multi-cylinder engine, the weight difference of each cylinder must not exceed 10 grams to ensure the balance of engine operation.

CNC precision parts product display

The precision parts’ actual shape accuracy is consistent with the drawing, including straightness, flatness, roundness, and cylindricity. It is generally controlled within the range of 0.1 to 0.5 μm, it can reach 0.05 μm in special cases.
For example, the camshaft, crankshaft, and other rotating parts need high-precision shape accuracy to ensure stability and reliability under high-speed operation.

Position accuracy refers to the part’s surfaces, including parallelism, verticality, coaxiality, and symmetry. It is generally controlled within the range of 0.01 to 0.05 mm, it can reach 0.005 mm in special cases.
Braking system components, such as brake discs and brake calipers require high-precision position accuracy to ensure reliability and stability.

Surface quality requirements include defects, roughness, waviness, and scratches. It directly affects the precision parts’ service life and appearance. The surface roughness is generally controlled within the range of Ra0.1~Ra0.4μm, it can reach Ra0.05μm in special cases.
For example, the cylinder bore, piston skirt, piston pin, and other parts need to undergo high-precision processing. The grinding process can achieve the required surface roughness and finish.

When we know the precision parts accuracy, which process technology is suitable for the parts? MK CNC engineers understand the CNC machine process technology.

Precision milling is a high-precision CNC machining process. It uses a rotating milling cutter to cut the workpiece to achieve complex shapes and sizes. The key to precision milling lies in high-precision machines. the milling machines with advanced tool systems, precise machining parameter control, and strict quality inspection.
The precision milling processes can achieve extremely high dimensional accuracy, the milling process usually reaching the micron level (μm), it allows the precision parts to meet strict tolerance requirements.
Precision milling can process complex three-dimensional shapes and structures, such as curved surfaces, slots, holes, etc.
Precision milling can produce high-quality surfaces, reducing the need for subsequent processing, such as polishing and grinding, thereby saving time and cost.
By optimizing processing parameters and automating operations, precision milling can significantly improve production efficiency and reduce processing time and labor costs.

Precision turning is a high-precision machining process, it mainly used to manufacture rotating precision parts with strict tolerances and high surface quality. It changes the workpiece’s shape through the lathe’s rotational and linear or curved motion.
Precision turning can achieve extremely high dimensional accuracy, the tolerance usually reaching IT6 – IT5, and the surface roughness (Ra value) can reach 0.8 – 0.2μm.
This high precision makes precision turning very suitable for manufacturing high-demand precision parts.
During the turning process, the workpiece rotates, and the cutting tool moves in a straight line. This processing method reduces the cutting force and cutting heat, which is conducive to improving the processing efficiency.
Precision turning can also use multi-tool cutting and automated production lines to further improve production efficiency.
During the turning process, the cutting force and cutting heat are small, and it is not easy to produce built-up edge and surface hardening, and a higher surface quality can be obtained.

The difference between precision turning and ordinary turning

Ordinary turning can reach IT8-IT7, the surface roughness Ra value of 1.6-3.2μm; while precision turning can reach IT6-IT5, with an Ra value of 0.8-0.2μm.
Precision turning can process more complex shapes and structures.
Precision turning usually uses CNC technology to achieve automated processing, while ordinary turning relies more on manual operation.

Precision grinding is a high-precision machining technology that uses abrasive particles to remove material from the workpiece to achieve extremely high dimensional accuracy and surface quality. It is often used to process precision parts that require tight tolerances and high surface finishes.
Precision grinding can achieve extremely high dimensional accuracy, usually up to 1 – 0.1μm, and surface roughness values can reach Ra 0.2 – 0.025μm.
Ultra-precision grinding has higher accuracy, reaching less than 0.1μm.
Precision grinding can achieve high-speed grinding and feed speeds, it can improve production efficiency, and the grinding process can reduce machining costs.

Types of Precision Grinding
Surface grinding is used to grind smooth and flat surfaces with tight tolerances ±0.0002 inches and surface roughness up to Ra ≤ 130 nm.
Cylindrical grinding is used to process cylindrical workpieces with diameter tolerances ±0.00004 inches and roundness tolerances of ±0.000025 inches.
Centerless grinding is used for high-volume production, processing 300 parts per minute with extremely tight tolerances ±0.0001 inches.
Jig grinding is used to manufacture parts with complex shapes with tolerances up to ±60,000 inches.

MK CNC is a precision parts manufacturer with 27 years of experience. We strictly control the part accuracy quality. Please send your drawings to us, and our engineer will provide suitable solutions!

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