Comprehensive CNC Machining FAQ
CNC Machining FAQ - Your Complete Guide
Welcome to Allied Metal’s Comprehensive CNC Machining Resource Center
Choosing the right CNC machining partner involves understanding complex processes, materials, and capabilities. This comprehensive FAQ addresses the most common questions we receive from engineers, procurement managers, and product developers across diverse industries.
Content in this Article
Consultation & Inquiry
Please provide technical drawings or 3D files (preferably STEP/IGES format), material specifications, quantity requirements, tolerance requirements, surface finish needs, and your target timeline. If you don’t have complete specifications, our engineering team can help develop them during consultation.
Standard quotes are provided within 24-48 hours for typical parts. Complex or high-precision components may require 2-3 business days for thorough analysis. Rush quotes can be provided within 4-6 hours for urgent projects.
Yes, we routinely sign NDAs to protect your intellectual property and proprietary designs. We maintain strict confidentiality protocols and can execute your NDA or provide our standard confidentiality agreement.
We accept orders starting from single prototypes. There’s no minimum order quantity, though unit costs decrease with higher volumes due to setup cost amortization.
Absolutely. Our engineering team provides Design for Manufacturing (DFM) analysis to optimize your designs for cost-effectiveness, improved quality, and faster production while maintaining functionality.
Technical Drawings & Design
We accept most common formats including STEP, IGES, STL, Solidworks (.sldprt), AutoCAD (.dwg), Inventor (.ipt), and PDF technical drawings. 3D native files are preferred for complex geometries.
Our engineering team can work from conceptual sketches, existing parts for reverse engineering, or basic requirements to develop complete technical specifications and 3D models.
Minor revisions can often be accommodated depending on production stage. We’ll assess the impact on timeline and cost, providing options to implement changes efficiently. Major changes may require restarting the production process.
Yes, we can generate complete technical drawings with dimensions, tolerances, and specifications from your 3D models. This service is particularly useful for documentation and quality control purposes.
We follow ISO 2768 general tolerance standards by default, but can work to any specification including ANSI, JIS, or custom tolerance requirements. We always clarify tolerance requirements before beginning production.
Materials & Material Selection
We machine a wide range of materials including aluminum alloys (6061, 7075, 2024), steel (carbon, alloy, stainless), titanium alloys, brass, bronze, copper, various plastics (ABS, PEEK, PTFE, Nylon), and exotic alloys like Inconel and Hastelloy.
Material selection depends on mechanical properties needed (strength, hardness, flexibility), environmental conditions (temperature, chemical exposure), weight requirements, cost considerations, and post-processing compatibility. Our team can provide material recommendations based on your application.
Yes, we provide mill test certificates for metals and material certifications for plastics when required. This includes chemical composition, mechanical properties, and traceability documentation for aerospace and medical applications.
Yes, we maintain relationships with specialty material suppliers and can source most engineering materials. Lead times vary based on material availability, typically 1-4 weeks for specialty alloys.
6061 offers good general-purpose properties and weldability; 7075 provides higher strength for aerospace applications; 2024 offers excellent fatigue resistance. We’ll recommend the optimal grade based on your specific requirements.
Machining Processes & Capabilities
We provide CNC milling (3, 4, and 5-axis), CNC turning, Swiss turning, EDM (wire and sinker), grinding, and combination machining. We also offer secondary operations like drilling, tapping, and assembly.
3-axis machines move in X, Y, and Z directions; 4-axis adds rotation around one axis; 5-axis allows simultaneous movement in all five directions. Higher axis counts enable more complex geometries, better surface finishes, and fewer setups.
Standard tolerances are ±0.005″ (±0.13mm). We routinely achieve ±0.002″ (±0.05mm) for critical dimensions and can reach ±0.0005″ (±0.013mm) for precision applications using specialized processes and inspection equipment.
Our capacity ranges from miniature components (1mm minimum features) to large parts up to 2000mm x 1500mm x 800mm. Swiss turning handles parts from 0.5mm to 32mm diameter with lengths up to 300mm.
We use precision measuring equipment including CMMs (Coordinate Measuring Machines), optical comparators, micrometers, and gauge blocks. In-process measurement and statistical process control ensure consistent accuracy throughout production.
Surface Treatment & Finishing
We provide anodizing (Type II and III), powder coating, plating (zinc, nickel, chrome), passivation for stainless steel, black oxide, heat treatment, and various mechanical finishes from rough machined to mirror polish.
Surface finish is specified using Ra (roughness average) values in micrometers or microinches. Standard machined finish is Ra 3.2μm (125μin). We can achieve Ra 0.1μm (4μin) with specialized processes.
Type II (decorative) anodizing provides corrosion protection and color options with 0.0002-0.001″ thickness. Type III (hard coat) creates a harder, thicker coating (0.001-0.004″) for wear resistance and electrical insulation.
Yes, most coatings add thickness. Anodizing adds 0.0001-0.002″ per surface, plating adds 0.0002-0.002″, and powder coating adds 0.002-0.008″. We account for these in machining dimensions.
Most treatments add 3-7 business days to lead time. Standard anodizing takes 3-5 days, powder coating takes 5-7 days, and specialty treatments may require 1-2 weeks depending on complexity and batch scheduling.
Quality Control & Inspection
We’re ISO 9001 certified and follow AS9100 for aerospace applications. We also comply with IATF 16949 for automotive and ISO 13485 for medical devices. Our quality management system ensures consistent results across all projects.
Our inspection capabilities include CMM machines, optical comparators, surface roughness testers, hardness testers, material analysis equipment, and precision measuring tools. All equipment is calibrated to NIST standards.
Yes, we provide first article inspection reports (FAIR), certificate of compliance, dimensional inspection reports, and material certifications as required. Reports can be customized to your specific documentation needs.
Non-conforming parts are quarantined immediately. We investigate root causes, implement corrective actions, and provide detailed reports. Depending on the deviation, parts may be reworked, accepted with concessions, or scrapped and remade.
Yes, we perform in-process inspection at critical stages to prevent defects and ensure quality. This proactive approach reduces scrap rates and ensures final parts meet specifications.
Lead Times & Production
Lead times vary by complexity: simple parts 3-5 days, moderate complexity 5-10 days, complex parts 10-15 days. First articles typically add 2-3 days for inspection and approval. Material availability and surface treatments can extend timelines.
Yes, we offer expedited service for urgent requirements. Rush orders typically incur 25-50% premium but can reduce lead times by 50-70%. Contact us for specific rush capabilities and pricing.
For volumes over 100 pieces, we optimize tooling, fixturing, and processes to maximize efficiency. We provide dedicated production schedules, volume pricing, and can implement lean manufacturing principles.
We work with customers to accommodate reasonable schedule changes. Early acceleration may incur rush charges, while delays can often be accommodated without penalty if communicated promptly.
Yes, we provide regular progress updates via email or phone calls. For complex projects, we can provide daily updates including photos and milestone completions.
Pricing & Payment
Pricing is based on material cost, machining time, setup complexity, tolerances, surface treatments, and quantity. We provide detailed quotes breaking down all cost components for transparency.
Yes, unit costs decrease significantly with higher quantities due to setup cost amortization and process optimization. Volume breaks typically occur at 10, 50, 100, and 500+ pieces.
Standard terms are Net 30 for established customers. New customers typically require 50% deposit with balance due on completion. We accept wire transfers, ACH, checks, and credit cards for smaller orders.
Absolutely. Our engineering team regularly suggests design modifications, material alternatives, tolerance optimization, and process improvements to reduce costs while maintaining functionality.
Potential additional charges include special tooling, engineering time for complex setups, expedite fees, special packaging, and third-party certifications. All charges are identified in the initial quote.
Shipping & Packaging
Parts are cleaned, inspected, and packaged in protective materials. Anti-static bags for electronics, foam padding for delicate parts, and wooden crates for large or fragile items. Custom packaging is available for specific requirements.
We ship via FedEx, UPS, DHL for standard deliveries, and freight carriers for large shipments. Options include ground, overnight, international shipping, and white glove delivery for sensitive items.
After-Sales Support
We can implement design changes for future orders. Depending on the changes, we may need to create new fixtures or tooling. We’ll provide cost and timeline impact assessment for any modifications.
Yes, we maintain all programs, tooling, and specifications for easy reproduction. Lead times for remake orders are typically shorter since setup is already optimized.
Yes, our engineering team provides ongoing technical support for assembly questions, design optimization, and troubleshooting. We’re committed to your long-term success, not just initial delivery.
Absolutely. We can transition from prototype to low-volume production to high-volume manufacturing, optimizing processes and tooling at each stage to maintain cost-effectiveness as your volumes grow.
Specialized Services
Yes, we can reverse engineer existing parts using CMM measurement, 3D scanning, and engineering analysis to create accurate 3D models and technical drawings for reproduction or improvement.
We provide sub-assembly services including mechanical fastening, press fitting, adhesive bonding, and functional testing. This reduces your handling and simplifies supply chain management.
es, we specialize in rapid prototyping using CNC machining and 3D printing. Our engineering team can help develop concepts from initial ideas through functional prototypes to production-ready designs.
Yes, we have experience with aerospace (AS9100), medical (ISO 13485), automotive (IATF 16949), and defense (ITAR) standards. We understand industry-specific requirements and maintain appropriate certifications.
We can arrange for material testing including tensile testing, hardness testing, chemical analysis, and certification through our network of qualified testing laboratories when required for critical applications.
Whether you’re developing your first prototype or scaling to high-volume production, this guide provides clear, practical answers to help you make informed decisions about your manufacturing needs. Our team at Allied Metal has compiled decades of machining expertise into this resource, covering everything from initial consultation through final delivery and ongoing support.
Contact our engineering team at: quote@alliedcn.com for questions not covered here
Request a custom consultation to discuss your specific project requirements
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