Xiamen Goldcattle, with 26 years in precision fasteners, crafts custom CNC expansion screws (M6-M30) for construction, automotive, and industrial use. Our range includes sleeve anchors and wedge bolts, made via advanced CNC machining. Backed by ISO 9001 and ASTM F1554, we deliver ±0.01mm tolerance parts—from prototypes to 1M+ units/month—ensuring reliable performance for 50+ global clients.
Core Processing Technologies: Engineering for Secure Fastening
CNC expansion screws demand precision to anchor reliably in concrete, metal, or wood. Goldcattle’s technologies ensure consistent performance across applications, from structural builds to furniture assembly.
1. CNC Precision Turning & Milling
- Swiss-type CNC turning: Produces screw bodies and sleeves with ±0.005mm shank tolerance, ensuring smooth expansion. A M12 sleeve anchor here maintains 30-35kN force across 10,000 units, eliminating looseness.
- CNC milling for drive heads: Creates hex, Phillips, or custom heads (±0.02mm) for tool compatibility. A aerospace M10 screw with a 12-point head withstands 50Nm torque without stripping.
- Thread rolling: Cold-forms threads (ISO metric/UNC) to boost tensile strength by 20-30%, ensuring secure engagement. M16 wedge anchors achieve 45kN pull-out in C30 concrete—15% higher than cut threads.
2. Heat Treatment & Surface Hardening
- Induction hardening: Hardens sleeves to 55-60 HRC (ductile core: 30-35 HRC) for uniform expansion without cracking, enduring 100+ installation cycles.
- Carburizing: Enhances M20-M30 bolts with 0.8-1.2mm hardened layers, resisting vibration in industrial machinery (20-2000Hz).
- Stress relief annealing: Eliminates machining stresses at 600-650℃, limiting deformation to ≤0.02mm over 12 months.
3. Surface Coating & Corrosion Resistance
- Zinc plating with passivation: Offers 500+ hours salt spray resistance (RoHS-compliant), ideal for indoor/mild outdoor use (furniture, fixtures).
- Hot-dip galvanizing: 85-100μm zinc coats resist 1,000+ hours of salt spray, suiting coastal bridges or marine builds.
- Electroless nickel plating: Provides 1,500+ hours corrosion resistance (uniform coverage on threads), ideal for aerospace and food-grade apps.
4. Quality Testing for Reliable Anchoring
- Dimensional checks: CMMs verify thread pitch (±0.01mm) and shank diameter (±0.005mm).
- Mechanical tests: Pull-out strength (e.g., M12 ≥18kN in C30 concrete), shear strength (≥30kN), and torque-to-failure (45-50Nm for M16).
- Environmental trials: Salt spray (500-2,000 hours), thermal cycling (-40℃ to 120℃), and humidity testing (95% RH) validate durability.
Material Expertise: Matching Materials to Expansion Screw Applications
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Material
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Treatment
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Use Cases
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Key Properties
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Carbon Steel (8.8/10.9)
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Zinc plating
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Construction, machinery
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800-1000MPa tensile strength; cost-effective for dry environments.
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304/316 Stainless Steel
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Passivation
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Marine, food plants
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316: 2,000+ hours salt spray; 515MPa strength.
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Alloy Steel (10.9/12.9)
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Hot-dip galvanizing
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Bridges, heavy machinery
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1000-1200MPa; M20 ≥40kN pull-out in C40 concrete.
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CNC Expansion Screw Machining Technologies
- Multi-axis CNC machining: 5-axis mills shape complex anchor geometries (e.g., tapered sleeves) with ±0.01mm accuracy, ensuring consistent expansion in variable substrates.
- Automated thread rolling: Computer-controlled rolling machines produce uniform threads on M6-M30 screws, reducing defects by 90% compared to manual processes.
- Robotic coating application: Ensures even zinc/electroless nickel coverage (±2μm thickness) on threads and sleeves, critical for corrosion resistance in harsh environments.
- In-line vision inspection: Cameras check 100% of parts for dimensional errors (e.g., thread pitch, head alignment) during production, maintaining 99.9% first-pass yield.
Custom CNC Expansion Screw Manufacturing Process
- Design & DFM: Engineers analyze client drawings (STEP/IGS) to optimize for manufacturability—e.g., adjusting sleeve tapers for concrete strength.
- Material selection: Choose steel/stainless based on environment (e.g., 316 for coastal areas) and load requirements (alloy steel for ≥40kN pull-out).
- CNC machining: Swiss turning creates screw bodies; milling shapes drive heads; thread rolling strengthens engagement surfaces.
- Heat treatment: Induction hardening/carburizing enhances wear resistance, followed by stress relief annealing to prevent warping.
- Coating application: Zinc plating, hot-dip galvanizing, or nickel plating applied per corrosion needs, with 100% adhesion testing.
- Quality validation: CMM inspection, pull-out testing, and salt spray trials ensure compliance with ASTM F1554 and client specs.
Custom Expansion Screw Application Fields
- Construction: Wedge anchors for concrete foundations, sleeve anchors for steel beam mounting (M16-M30, hot-dip galvanized).
- Automotive: 304 stainless steel expansion screws for chassis mounting, resisting road salt and vibration (M6-M12).
- Industrial machinery: Alloy steel screws with carburized threads for heavy equipment anchoring, enduring 1M+ vibration cycles (M12-M24).
- Furniture & fixtures: Brass/M8 screws with decorative heads for wooden furniture, ensuring flush mounting and corrosion resistance.
- Aerospace: Titanium alloy anchors for lightweight structural fastening, with electroless nickel plating (M8-M16).
Customization Capabilities: From Design to Delivery
- Design collaboration: Engineers optimize length (20-300mm), drive types, or coatings. A construction client’s M20 150mm screw with custom hex heads reached prototypes in 5 days.
- Application-specific solutions:
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- Construction: Hot-dip galvanized wedge anchors for concrete.
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- Automotive: 304 stainless screws resistant to road salt.
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- Furniture: M6-M8 brass screws with flush heads.
- Production flexibility: 10-100 prototypes (3-5 days); 100k-1M+ units/month via automated lines.
Common Processing Questions
- Q: How to ensure uniform expansion in weak concrete?
A: We design sleeves with variable wall thickness (thicker at the base) and test in C20-C40 concrete to adjust expansion force (15-50kN) for substrate strength.
- Q: Can screws withstand high vibration (e.g., industrial machinery)?
A: Yes—carburized alloy steel screws with rolled threads endure 1M+ 20-2000Hz cycles without loosening, meeting DIN 1029 standards.
- Q: What’s the lead time for custom M30 anchors (10k units)?
A: 7-10 days for tooling, 15-20 days for production. Rush options cut lead time by 30% with expedited machining.
- Q: How to prevent thread stripping during installation?
A: Thread rolling (vs. cutting) increases thread strength by 25%, while drive heads are tested to 120% of recommended torque (e.g., 60Nm for M16).
Why Choose Goldcattle?
- Expertise: 26 years in fasteners, with 100+ designs meeting ASTM/DIN standards.
- Quality: 100% CMM inspection and pull-out testing; full traceability from raw material to delivery.
- Efficiency: Automated lines reduce costs by 15%; material optimization cuts waste by 10%.
- Compliance: RoHS/REACH-certified, suitable for global projects (EU, US, ASEAN).
Start Your Project Today
Need custom expansion screws? Send drawings or specs to [email:charlie@plasticmetalparts.com] . Get a feasibility report and quote within 24 hours.
“Goldcattle’s M20 anchors solved our coastal bridge corrosion issues—2,000-hour salt spray resistance and 40kN pull-out strength. Reliable for 50-year projects.” — Infrastructure Client
Contact: charlie@plasticmetalparts.com
Address: 402, 1730 Gangzhong Road, Xiamen, Fujian, China
