I. Tolerance (The Most Critical Gap)

Conventional Machining

Tolerance range: ±0.05mm ~ ±0.1mm

Slight deviations visible to naked eyes or calipers are acceptable. It only meets basic assembly requirements, and relatively large gaps are permissible.

Applications: Equipment brackets, housings, general‑purpose hardware accessories.

Precision Parts Machining

Tolerance range: ±0.001mm ~ ±0.005mm

The error is far thinner than a human hair. Minor dimensional deviations will cause assembly jamming, abnormal operating noise and loss of equipment accuracy.

Applications: Automation movement components, medical accessories, optical communication modules, optical instruments, semiconductors, core auto parts.

II. Processing Equipment

Conventional Machining: Ordinary CNC lathes, 3‑axis basic CNC machines, standard milling machines, bench‑type drilling machines. Low equipment cost with moderate rigidity. High labor cost, and precision can hardly be guaranteed.

Precision Machining: 5‑axis machining centers, turn‑milling composite machines, internal‑external cylindrical grinders, wire‑cut EDM, mirror‑surface grinding equipment. Machine tools feature high rigidity and high factory‑set accuracy grade.

III. Surface Quality

Conventional Machining: Obvious tool marks, minor burrs and scratches are acceptable with loose requirements for surface roughness.

Precision Machining: Burr‑free and tool‑mark‑free surfaces with extremely low roughness values. Fine post‑treatments such as anodizing, polishing and passivation are commonly applied.

IV. Inspection Methods

Conventional Machining: Rough sampling inspection only with vernier calipers and tape measures.

Precision Machining: Full‑dimension inspection via coordinate measuring machines (CMM), micrometers, profilometers and roughness testers; inspection reports are archived.

V. Material Selection

Conventional Machining: General‑purpose materials such as ordinary carbon steel and recycled aluminum alloy.

Precision Machining: Higher‑stability materials including aerospace‑grade aluminum, 316 stainless steel, titanium alloy, PEEK engineering plastic and alloy tool steel.

VI. Cost & Lead Time

Conventional Machining: Low unit price, low MOQ requirement and fast delivery.

Precision Machining: Numerous working procedures and strict multi‑step quality inspection for timely problem detection and handling. It demands highly‑skilled operators, resulting in higher prices and longer lead‑times.

VII. Application Comparison

Conventional Machining: Shelf hardware, chassis housings, simple agricultural machinery parts, standard fasteners

Precision Machining: Automation equipment spare parts, endoscope components, lens structural parts, new‑energy electronic‑control hardware, bearing accessories

Dongguan Runjie Precision Machinery Co., Ltd. specializes in precision mechanical parts, precision tooling & fixtures, tungsten carbide parts, ceramic components, precision hardware molds and PLC‑based automated production equipment. Inquiries and factory visits are warmly welcomed.