303 stainless steel non-standard turning parts (external hexagon/internal/external/hollow screws) are specially designed fasteners. The following is a detailed customization description of it, which takes into account both professionalism and practicality.
1. Core customization parameters
Material requirements
303 stainless steel (easy-to-cut type), and a material report is required.
Optional additional treatment: passivation, which can improve corrosion resistance
Structural type
External hexagon head: width across flats, thickness
Internal/external thread: thread specifications (metric/imperial/American standard), accuracy grade (6H/6g)
Hollow design: through hole inner diameter, wall thickness tolerance
Key size tolerance
Outer diameter: ±0.05mm (precision turning parts)
Length: ±0.1mm (≤50mm), ±0.2mm (＞50mm)
Coaxiality: ≤0.03mm (Hollow screws need special marking)
Surface treatment
Default: Natural polishing (Ra≤0.8μm)
Optional: Nickel plating (5-10μm), electrolytic polishing (medical grade)
II. Notes on non-standard design
Special requirements for threads
Cross-section drawings are required for non-standard tooth types
The size of the back-cutting groove must be marked for internal blind holes (recommended ≥1.5 times the pitch)
Mechanical properties
Tensile strength ≥500MPa (pre-notice if heat treatment is required)
Head torque test (according to DIN 912 standard or customer-specified value)
Hollow structure verification
Flow test (fluid parts need to provide pressure level)
Wall thickness ultrasonic test report (optional)
III. Production and quality inspection process
Processing technology
Turning: CNC Swiss machine (suitable for small parts of φ3-20mm)
Thread processing: die/extrusion molding (external teeth), tap/thread milling (internal teeth)
Quality control
Full inspection items: head size, thread go/no-go gauge (GO/NO-GO)
Sampling inspection items: salt spray test (72h neutral salt spray), hardness (HRB 70-90)
Document delivery
Required: material certification, dimension inspection report, surface treatment process sheet
Optional: 3D drawings (STEP format), PPAP files (automotive industry)
IV. Typical application scenarios
Medical devices: hollow screws for diversion pipes (electrolytic polishing required)
Automation equipment: non-standard hexagonal parts for servo motor installation
Semiconductors: ultra-high cleanliness 303 stainless steel screws (vacuum degassing treatment)
V. Quotation instructions
Minimum order quantity: 50-100 pieces (trial production). Molds can be opened for more than 1,000 pieces
Delivery time: 7-15 days (adjusted depending on complexity)
Mold fee: non-standard tooth type/special-shaped structure needs to be calculated separately
Providing samples or CAD drawings can speed up the quotation process. For complex parts, it is recommended to sign a technical agreement to clarify the acceptance criteria.
Through the above layered analysis, the functional essence and design boundaries of such non-standard parts can be quickly grasped, which is convenient for engineering selection or customization communication.
