Have you ever wondered why some CNC machining projects turn out perfectly, while others have flawed dimensions or rough surfaces? The answer often lies in skipping or rushing key steps. CNC machining is a systematic process—each stage builds on the last to ensure accuracy and quality. Ce guide décompose le 7 cœur CNC machining steps, solving common pain points and giving you a roadmap to successful projects, whether you’re making a prototype or a production part.
1. Analyse des exigences: Jeter les bases du succès
Before touching a machine, you need to clarify what the final workpiece needs to achieve. This step is like planning a trip—without knowing the destination, you’ll likely get lost.
What to Cover in Requirements Analysis
- Design Requirements: Understand the workpiece’s purpose (Par exemple, a gear for a machine or a bracket for electronics). Note critical details from the design drawing, such as 3D shape and assembly needs.
- Propriétés des matériaux: Choisissez le bon matériau (Par exemple, aluminum for light parts, stainless steel for strength) and confirm its hardness, machinabilité, et résistance à la chaleur. Par exemple, a part used in high-temperature engines needs heat-resistant alloy like Inconel.
- Tolérances dimensionnelles & Rugosité de surface: Define how precise the part must be. A medical component might need a tolerance of ±0.005mm, while a simple bracket could use ±0.1mm. Rugosité de surface (Valeur RA) matters too—Ra 0.8μm for visible parts vs. Ra 6.3μm for hidden components.
Problème commun résolu: “Why did my part fail to fit with other components?»
You skipped clarifying assembly requirements! During analysis, demander:
- Will the part connect to other parts? (Note hole positions and thread sizes.)
- Does it need to withstand weight or pressure? (Choose a material with matching strength.)
Here’s a checklist to ensure you don’t miss anything:
- Review the design drawing with the customer/engineer.
- Document material type, tolérance, et finition de surface.
- Confirm the workpiece’s intended use (Par exemple, indoor vs. de plein air, chargement vs. décoratif).
2. Conception de processus: Plan the Machining Strategy
Once requirements are clear, you need to map out comment to make the part. This step is like creating a recipe—you decide the order of steps, outils, and fixtures.
Key Elements of Process Design
- Process Route Design: Choose the order of machining operations. For a cylindrical part, the route might be: Turn the outer diameter → Drill a hole → Mill a slot. Avoid unnecessary steps—e.g., don’t mill before turning if it could damage the part.
- Sélection d'outils & Configuration: Pick tools based on material and operation. Use a carbide end mill for aluminum (coupure rapide) and a high-speed steel drill for stainless steel (handles hardness). Ensure tools have the right size—e.g., a 5mm drill for a 5mm hole.
- Conception de luminaire & Installation: Fixtures hold the material in place. For a flat metal sheet, use a vice with soft jaws to avoid scratching. For irregular shapes, design a custom fixture to keep the part stable during machining.
The table below compares good vs. bad process routes for a simple aluminum bracket:
| Aspect | Good Process Route | Bad Process Route |
| Operation Order | Cut the sheet to size → Drill holes → Mill edges | Mill edges → Cut to size → Drill holes |
| Choix d'outil | Carbide end mill (rapide, smooth cuts) | High-speed steel mill (lent, surface rugueuse) |
| Fixture Use | Custom jaw to hold the sheet flat | No fixture (part shifts during drilling) |
| Résultat | Accurate holes, bords lisses | Misaligned holes, bent edges |
3. Programmation CNC: Turn Design into Machine Instructions
CNC machines don’t read drawings—they need code. Programming converts your design into a language the machine understands (G-code/M-code).
Steps to CNC Programming
- Modélisation CAO: Create a 3D digital model of the part using software like SolidWorks or AutoCAD. Ensure the model is error-free (no missing faces or overlapping edges).
- Programmation de came: Utiliser le logiciel CAM (Par exemple, Mastercam, Fusion 360) pour générer des parcours d'outils. Set parameters like cutting speed (1000 RPM for aluminum) et le taux d'alimentation (500 mm / min). The software turns the 3D model into G-code.
- Simulation de programme & Optimisation: Run a virtual simulation to check for collisions (Par exemple, tool hitting the fixture). Optimize the program—e.g., shorten tool travel time to speed up machining.
Exemple: A programmer is making a 3D model of a plastic knob. They use SolidWorks to create the model, then Mastercam to set a 2000 RPM cutting speed for plastic. Simulation reveals the tool almost hits the fixture—they adjust the toolpath to fix it.
4. Machine Tool Preparation: Get the Machine Ready to Run
Even the best program fails if the machine isn’t set up right. This step ensures everything is calibrated and in place.
Preparation Tasks
- Machine Tool Calibration: Check the machine’s accuracy (Par exemple, use a dial indicator to test spindle runout). If the spindle is off by 0.01mm, the part will have dimensional errors.
- Installation d'outils & Étalonnage: Install tools in the tool holder and set their length / 直径 offsets. Use a tool setter to measure tool length—this tells the machine where the tool tip is. Par exemple, a 10mm end mill needs its length offset set to 50mm from the spindle.
- Installation de luminaire & Débogage: Mount the fixture on the machine table and align it with the spindle. Test the fixture by clamping a sample material—ensure it doesn’t move when pressure is applied.
Problème commun résolu: “Why is my tool leaving uneven cuts?»
You forgot to calibrate tool length! If the tool length offset is wrong by 0.5mm, the machine will cut too deep or too shallow. Always use a tool setter to confirm offsets.
5. Exécution d'usinage: Laissez la machine faire le travail
With setup complete, the machine runs the program automatically. But you still need to monitor to catch issues early.
What Happens During Execution
- Brouillage: Retirez rapidement la majeure partie de l'excès. For a 100mm aluminum block being turned into a 50mm cylinder, roughing cuts away 40% of the material in fast, deep passes.
- Semi-finisse: Refine the shape, bringing it closer to the final dimensions. Cuts are shallower (Par exemple, 0.5MM par passe) and faster than roughing.
- Finition: Make the final, coupes précises. Utilisez des taux d'alimentation lents (Par exemple, 200 mm / min) and sharp tools to achieve the desired surface finish. For a part needing Ra 1.6μm, finishing passes smooth out any rough spots.
Pour la pointe: Stay nearby during the first 10 Minutes d'usinage. If the tool is chattering (making a loud noise) or the material is melting, stop the machine—you may need to adjust cutting speed or tool alignment.
6. Inspection de qualité: Ensure the Part Meets Requirements
You can’t assume the part is perfect—inspection verifies it meets all specs. This step is like proofreading an essay before submitting it.
What to Inspect
- Inspection dimensionnelle: Utilisez des outils comme des étriers (for simple measurements), micromètres (pour précision), et cmm (Coordonner la machine à mesurer) for complex 3D parts. Check if all dimensions match the drawing (Par exemple, diamètre du trou, longueur de pièce).
- Shape Inspection: Look for deformities like warping or bending. A flat part should lie perfectly on a surface plate—if it rocks, it’s warped.
- Surface Quality Inspection: Vérifiez les rayures, fouillis, ou inégalité. Use a surface roughness tester to confirm Ra value, or visually inspect for visible flaws.
Exemple: A manufacturer inspects a batch of 100 supports. They use a CMM to check 10 random parts—9 are within ±0.05mm tolerance, mais 1 has a hole 0.1mm off. They adjust the program and re-inspect to avoid more defects.
7. Post-traitement: Polish the Final Part
Even a precise part may need extra steps to improve performance or appearance. Post-processing is like adding the final touches to a painting.
Common Post-Processing Operations
- Débarquant: Remove sharp edges or small metal shavings (fouillis) using a file, papier de verre, or deburring tool. Burrs can cut hands or damage other parts during assembly.
- Traitement thermique: Strengthen the material (Par exemple, annealing aluminum to reduce brittleness, quenching steel for hardness). A tool part might undergo heat treatment to withstand heavy use.
- Traitement de surface: Improve appearance or durability. Options include:
- Anodisation (for aluminum parts—adds a colored, couche résistante à la corrosion).
- Peinture (for visible parts like consumer electronics).
- Placage (Par exemple, chrome plating for a shiny, wear-resistant finish).
Perspective de la technologie Yigu
À la technologie Yigu, Nous voyons CNC machining steps as the backbone of precision manufacturing. Many clients face delays or defects because they rush steps like requirements analysis or calibration. Our solutions include a step-by-step checklist for each stage, plus AI-powered simulation tools to catch programming errors early. We also train teams to prioritize inspection—because a small flaw early becomes a big problem later. As CNC tech advances, we’ll integrate more automation (Par exemple, auto-calibration) to simplify steps, helping clients cut time while keeping quality high.
FAQ
1. Can I skip the simulation step in CNC programming?
No—simulation is critical to avoid costly mistakes. Skipping it could lead to tool collisions (breaking tools or damaging the machine) or incorrect toolpaths (ruining the material). Even for simple parts, a 5-minute simulation saves hours of rework.
2. How long does the CNC machining process take for a single part?
It depends on the part’s complexity and step speed. A simple aluminum bracket might take 30 minutes (10 mins setup, 15 mins machining, 5 mins inspection). A complex medical part could take 2–3 hours (more time for precision programming and inspection).
3. What if the part fails quality inspection?
D'abord, identifier la cause: Was it a programming error (fix the code), usure (replace the tool), or material issue (switch materials)? For small defects (Par exemple, a tiny burr), rework the part with post-processing. For major issues (Par exemple, wrong dimensions), restart from the process design step to correct the root problem.