Processus d'usinage de pliage CNC: Un guide étape par étape pour le travail de tôlerie de précision

In sheet metal manufacturing, achieving consistent, accurate bends is critical—yet traditional manual bending often struggles with human error, inconsistent angles, and slow throughput. Le CNC bending machining process solves these pain points by combining computer-controlled precision with automated operation, making it ideal for mass-produced parts (comme les supports automobiles) and custom components (such as electrical enclosures). Whether you’re a production manager aiming to reduce scrap rates or a technician learning to optimize setup, this guide breaks down the CNC bending process, common challenges, and solutions to ensure high-quality results.

1. What Is the CNC Bending Machining Process? Définition de base & Avantages clés

Avant de plonger dans les étapes, let’s clarify what makes CNC bending different from traditional methods:

Définition clé

Le CNC bending machining process is a computer-controlled manufacturing technique that uses a press brake to bend sheet metal (Par exemple, acier, aluminium) into predefined shapes. It relies on 3D CAD designs and CAM-generated programs to automate critical parameters—including bending sequence, angle, pression, and tool positioning—eliminating manual guesswork.

Why Choose CNC Bending Over Manual Bending?

A side-by-side comparison highlights the efficiency and precision benefits:

2. Step-by-Step Breakdown of the CNC Bending Machining Process

The CNC bending process follows a linear, repeatable workflow—from design to inspection. Each step builds on the previous one to ensure accuracy:

Étape 1: Conception & Programmation

This foundational step sets the stage for error-free bending:

1. Design CAO: Utiliser un logiciel (Par exemple, Solide, Autocad) to create 2D/3D drawings of the bent part. Critical details include:

• Final bend angles (Par exemple, 90°, 45°)
• Material thickness (Par exemple, 2Aluminium MM)
• Bend radius (to avoid material cracking)

2. Programmation de came: Import the CAD file into CAM software (Par exemple, Mastercam, FAO SolidWorks) to generate the press brake program. The software calculates:

• Bending sequence (order of bends to avoid tool collisions—e.g., bend the innermost angles first)
• Press force (Par exemple, 50 kN for 2mm steel)
• Sélection d'outils (matching upper/lower dies to the part’s shape)

Pour la pointe: Always add a “flat pattern” to the CAD file—this shows the unbent sheet metal size, which is critical for cutting.

Étape 2: Préparation des matériaux

Using the wrong material or size leads to failed bends. Suivez ces étapes:

1. Sélection des matériaux: Choose metal based on part requirements:

• Plaques d'acier (Par exemple, Q235): Pour les pièces à haute résistance (Par exemple, cadres de machines)
• Aluminum plates (Par exemple, 6061): Pour les pièces légères (Par exemple, garniture automobile)
• Acier inoxydable (Par exemple, 304): For corrosion-resistant parts (Par exemple, équipement pour l'industrie alimentaire)

2. Coupe: Use CNC shearing or laser cutting to trim large material into “blanks” (sheets matching the flat pattern size). Par exemple:

• A 200mm × 150mm blank for a 100mm × 50mm × 50mm box part.

Étape 3: Configuration de la machine & Installation du moule

Incorrect setup is the #1 cause of oversized or misshapen parts. Here’s how to avoid it:

1. Die Selection: Match upper (punch) and lower (mourir) dies to the part’s bend radius:

• Use a 3mm radius die for 2mm aluminum (empêche la fissuration)
• Use a V-shaped die (Par exemple, 8mm V-width) for 90° bends

2. Die Installation: Mount dies on the press brake’s upper ram (punch) and lower table (mourir). Secure them with clamps to avoid movement during bending.
3. Étalonnage de la machine: Adjust press brake parameters via the CNC control panel:

• Pression: Régler sur 40 kN for 1.5mm steel (too much pressure crushes the material; too little leaves incomplete bends)
• Vitesse: 5–10 mm / s (faster speeds risk vibration; slower speeds reduce efficiency)
• Backgauge position: Align the backgauge (a stop that positions the blank) to the first bend’s location (Par exemple, 50mm from the die edge).

Étape 4: CNC Bending Execution

This is the automated phase—but operator supervision is still key:

1. Part Positioning: Place the cut blank on the press brake table. The backgauge pushes the blank to the correct position (no manual measuring needed).
2. Program Start: Press “run” on the CNC panel. The press brake:

• Lowers the upper die (punch) to contact the blank
• Applies the preset pressure to bend the material
• Retracts the punch to release the bent part

3. In-Process Check: After the first 2–3 parts, measure angles with a protractor to confirm accuracy. If off by 0.5°, adjust the CNC program’s angle offset.

Étape 5: Post-traitement & Inspection de qualité

Even a perfectly bent part needs finishing and verification:

1. Débarquant: Use a file or sanding tool to remove sharp edges from bend points (prevents injury and improves part fit).
2. Inspection de qualité: Check key dimensions against the CAD file:

• Bend angle (use a digital protractor for ±0.05° accuracy)
• Part size (Par exemple, 100mm × 50mm for the box part)
• Qualité de surface (pas de fissures, bosses, or material deformation)

Exemple: Un fabricant produisant 1,000 aluminum electrical enclosures followed this process—scrap rate dropped from 12% (manual bending) à 3%, and production time was cut by 60%.

3. Common Challenges in CNC Bending & Comment les résoudre

Even with automation, Les problèmes peuvent survenir. Here’s how to troubleshoot:

4. Yigu Technology’s Perspective on CNC Bending Machining Process

À la technologie Yigu, Nous avons soutenu 250+ sheet metal manufacturers in optimizing their CNC bending machining process. De notre expérience, 70% of inefficiencies come from outdated programming or poor setup. Notre Yigu CNC Press Brakes feature auto-calibration (cuts setup time by 40%) and integrated CAM software (preloads 1000+ bend parameters for common materials). For small shops, our training program teaches operators to reduce scrap rates to <5%—a client making automotive brackets saw a 50% productivity boost after 1 week of training. We also offer custom die sets for complex parts (Par exemple, curved bends), ensuring clients avoid tool-related delays.

FAQ: Common Questions About CNC Bending Machining Process

1. Q: How do I calculate the right press force for CNC bending?

UN: Utilisez la formule: Force (KN) = Material Thickness (MM) × Material Width (MM) × Material Factor (Par exemple, 2.5 pour l'acier, 1.5 pour l'aluminium). Par exemple, 2mm steel × 100mm width × 2.5 = 500 KN. Most CNC press brakes have built-in calculators to simplify this.

2. Q: Can CNC bending handle thin materials (Par exemple, 0.5Aluminium MM)?

UN: Yes—but use a low-pressure setting (20–30 kN) and a narrow V-die (4Largeur MM) to avoid material warping. Aussi, add a “hold time” (1–2 secondes) in the program to let the material set before releasing.

3. Q: How often should I maintain a CNC press brake for bending?

UN: Tous les jours: Clean die surfaces and check clamp tightness. Hebdomadaire: Lubricate backgauge rails and calibrate pressure. Mensuel: Inspect die wear (replace if edges are chipped) and test emergency stops. Following this schedule extends machine life by 3–5 years.