Dans fabrication industrielle, pourquoi faire 98% of high-quality screw producers rely on CNC machine tool processing screws instead of traditional manual lathes? La réponse réside dans la capacité de la CNC à résoudre les problèmes critiques, comme les dimensions de filetage incohérentes., cycles de production lents, et des taux de rebut élevés, qui nuisent aux méthodes manuelles. Cet article détaille le flux de travail complet, paramètres clés, sélection d'outils, contrôle de qualité, and real-world applications of CNC screw processing, helping you achieve uniform, efficace, and cost-effective screw production.
What Is CNC Machine Tool Processing Screws?
Vis de traitement de machines-outils CNC is an automated manufacturing process that uses Computer Numerical Control (CNC) lathes or machining centers to produce screws—critical fasteners used in machinery, électronique, et construction. Unlike manual processing (where operators manually adjust tool positions and cutting speeds), CNC systems follow pre-programmed G-code and M-code to control every step: from shaping the screw’s outer diameter to cutting precise threads.
Think of it as a “digital craftsman” for screws: it executes repetitive tasks with micron-level accuracy, ensuring every screw matches design specs (par ex., thread pitch, head shape) perfectly—even for high-volume production runs of 10,000+ unités.
Full Workflow of CNC Machine Tool Processing Screws
CNC screw processing follows a linear, error-proof sequence—each step builds on the last to avoid defects. Below is the detailed workflow with actionable tips:
- Préparation du matériel
- But: Select raw materials that match the screw’s strength and corrosion resistance needs.
- Matériaux courants:
- Carbon steel (for general-purpose screws, par ex., DEPUIS 933 boulons).
- Acier inoxydable (304/316, for corrosion-resistant screws in medical/ marine applications).
- Alliage de titane (for high-strength screws in aerospace).
- Form: Use metal bar stock (diameter 3mm–50mm) or wire—bar stock is ideal for thick screws, while wire suits thin, small screws.
- Tip: Dry materials at 80°C for 2 hours if stored in humid environments—moisture causes surface rust during machining.
- Clamping & Positionnement
- Processus: Secure the raw material to the CNC lathe’s spindle chuck or collet.
- Accuracy Requirement: Use a dial indicator to check runout (radial deviation) < 0.01mm—excess runout leads to uneven thread depth.
- Solution for Long Materials: For bar stock longer than 300mm, use a tailstock center to support the free end (prevents bending during rotation).
- Sélection d'outils
The right tool determines thread quality and tool life. Use this table to match tools to screw types:
| Screw Feature | Recommended Tool Type | Avantage clé |
| Outer circle turning | Carbide turning inserts (CCMT 09T304) | Haute résistance à l'usure; handles cutting speeds up to 200 m/min for steel. |
| Thread cutting (externe) | Indexable threading inserts (16IR 1.5 OIN) | Quick tool change; uniform thread profile (60° included angle for metric screws). |
| Screw head shaping | Acier rapide (HSS) fraises en bout | Sharp cutting edge; ideal for shaping hexagon or pan heads. |
- Programmation CNC
- Core Codes:
- G76: Thread cutting cycle (sets pitch, profondeur, and number of passes).
- G01: Linear interpolation (moves tool to thread start position).
- M03: Spindle rotation (clockwise for right-hand threads).
- Example Program Snippet for M5×0.8mm Screw:
G00 X7 Z5; (Position tool above material)G76 P020060 Q0.005 R0.01; (Set thread quality: 2 passes, 60° angle, 0.005mm minimum cut)G76 X4.2 Z-15 P0.583 Q0.3 F0.8; (Cut thread: minor diameter 4.2mm, length 15mm, pitch 0.8mm)- Tool for Complex Screws: Use CAD/CAM software (par ex., Mastercam) to generate programs for screws with non-standard threads (par ex., trapezoidal threads for lead screws).
- Simulation & Trial Machining
- Simulation: Use the CNC system’s virtual simulation function to check for tool collisions (par ex., tool hitting chuck) or overcuts (excessive material removal).
- Trial Run: Machine 1–2 test screws first. Inspect:
- Thread pitch (use a thread gauge).
- Outer diameter (use a micrometer).
- Head flatness (use a surface plate and feeler gauge).
- Adjustment: If thread depth is 0.05mm too shallow, increase the “P” value in G76 by 0.05mm.
- Formal Machining
- Paramètres de coupe: Optimize based on material (voir tableau ci-dessous):
| Matériel | Cutting Speed (m/mon) | Vitesse d'alimentation (mm/rev) | Depth of Cut per Pass (mm) |
| Acier au carbone (45#) | 150–180 | 0.15–0.2 | 0.2–0,3 |
| Acier inoxydable (304) | 80–120 | 0.1–0.15 | 0.15–0.25 |
| Alliage de titane (Ti-6Al-4V) | 50–80 | 0.08–0.12 | 0.1–0.2 |
- Surveillance: Listen for abnormal noises (par ex., squealing = tool wear) — replace tools if wear exceeds 0.1mm.
- Contrôle qualité
- Key Metrics & Outils:
- Thread pitch: Thread plug gauge (pour filetage interne) or ring gauge (pour filetage externe).
- Précision dimensionnelle: Machine de mesure de coordonnées (MMT) — tolerance ±0.02mm for critical screws.
- Rugosité de la surface: Profilometer — Ra < 1.6 μm for visible screws; Râ < 0.8 μm for precision machinery screws.
- Sampling Rate: Inspect 5% of screws for small batches (100–500 unités); 1% for large batches (10,000+ unités).
- Post-Treatment
- Ébavurage: Use a nylon brush or tumbler (10 minutes) to remove burrs on thread roots (prevents hand injury during assembly).
- Traitement de surface:
- Zinc plating (for carbon steel screws — improves corrosion resistance).
- Passivation (for stainless steel — enhances surface oxide layer).
- Traitement thermique: For high-strength screws, quench and temper at 850°C (increases tensile strength to 800 MPa+).
CNC vs. Traditional Screw Processing: A Critical Comparison
Why switch to CNC? The table below highlights the gap in efficiency and quality:
| Aspect | CNC Machine Tool Processing | Traditional Manual Lathe |
| Production Speed | 30–50 screws per hour (M5 size). | 8–12 screws per hour (M5 size). |
| Thread Accuracy | Pitch tolerance ±0.005mm; 99.5% cohérence. | Pitch tolerance ±0.05mm; 85% cohérence. |
| Taux de rebut | <1% (simulation + trial run reduce errors). | 8–12% (operator error, usure des outils). |
| Labor Requirement | 1 operator manages 2–3 CNC lathes. | 1 operator per lathe (full-time supervision). |
Real-World Application Case: Aerospace Screw Manufacturing
- Défi: An aerospace firm needed titanium alloy screws (M8×1.25mm) avec:
- Tensile strength > 900 MPa.
- Thread tolerance class 4h (strict for aircraft engine mounting).
- Corrosion resistance to jet fuel.
- CNC Solution:
- Matériel: Titanium alloy Ti-6Al-4V bar stock (diameter 10mm).
- Outils: Carbide threading inserts (16IR 1.25 OIN) with TiAlN coating (resists high heat).
- Parameters: Cutting speed 60 m/mon, feed rate 0.1mm/rev, 8 thread passes.
- Post-treatment: Passivation + traitement thermique (900°C quenching).
- Résultat:
- Scrap rate dropped from 15% (traditionnel) à 0.8%.
- Production time per 1000 screws cut from 83 heures pour 20 heures.
- All screws passed aerospace industry testing (ASTM F568M standard).
Yigu Technology’s Perspective
Chez Yigu Technologie, we see CNC machine tool processing screws as the foundation of reliable industrial fastening. Our CNC lathes (YG-2000 series) are optimized for screw production: they have auto-tool change systems (cut tool change time by 60%) and real-time thread quality monitoring (alerts for pitch deviations > 0.003mm). We’ve helped automotive clients cut screw production costs by 35% and aerospace firms achieve 4h thread tolerance consistently. As demand for micro-screws (M1 à M3) grows, we’re integrating high-precision spindles (runout < 0.005mm) to support next-gen electronics manufacturing.
FAQ
- Q: What’s the minimum screw size CNC machines can process?
UN: Our standard CNC lathes handle screws as small as M1×0.25mm (diameter 1mm, pitch 0.25mm). For micro-screws (M0.5×0.1mm), we offer custom machines with ultra-fine collets (0.5mm diamètre) and high-frequency spindles (40,000 RPM).
- Q: How to reduce tool wear when processing stainless steel screws?
UN: Use tools with TiAlN or diamond coatings (increase wear resistance by 2x). Aussi, apply cutting fluid (water-soluble for 304 acier) to reduce friction—fluid flow rate should be > 5 L/min.
- Q: Can CNC process both metric and imperial screws?
UN: Oui! Our CNC systems support both metric (OIN) and imperial (UNC/UNF) thread standards. Just input the thread pitch (par ex., 0.8mm for metric M5, 0.0315” for imperial #10-32) in the G76 cycle—no hardware changes needed.