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Q1: What materials can you process for custom CNC machined parts?
A1: We machine a wide range of metals and engineering plastics. Metals include aluminum alloy, stainless steel, titanium alloy, copper and brass. Engineering plastics cover PTFE, PA66, POM, PVC, PE and PMMA. If you need special or exotic materials, please send us your requirement and we will check availability.
Q2: How should I select the right material for my CNC component?
A2: Material selection depends on your working conditions, including operating temperature, load force, corrosion environment, weight requirement and electrical insulation needs. Our engineering team can give professional material recommendations once you share your application, helping you balance performance and cost.
Q3: What are the advantages of aluminum alloy for CNC machining?
A3: Aluminum alloy is one of the most popular CNC materials. It is lightweight, easy to machine, has good thermal conductivity, and supports various surface treatments such as anodizing. It is widely used for automation frames, semiconductor fixtures, robotic components and heat dissipation parts.
Q4: What are the characteristics of stainless steel and titanium alloy parts?
A4: Stainless steel offers excellent corrosion resistance and high structural strength, suitable for hydraulic, vacuum and marine equipment. Titanium alloy has ultra-high strength-to-weight ratio and outstanding heat and corrosion resistance. It is commonly used in aerospace, medical and high-end precision equipment, while its machining cost is relatively higher.
Q5: Can you machine engineering plastic parts like PTFE and POM?
A5: Yes. We have rich experience in machining non-metallic engineering plastics. PTFE features excellent insulation and corrosion resistance. POM has high hardness and good wear resistance for gear and bushing parts. Plastic parts need special clamping and cutting parameters to avoid deformation during processing.
Q6: Can you provide material certificates for the raw materials?
A6: Yes. We can supply material test certificates (MTC) upon request, which record raw material composition and property data. This document is often required for aerospace, medical and semiconductor projects to meet industry compliance standards.
Q1: What files do I need to submit to get a CNC machining quotation?
A1: The most essential file is 3D CAD file in STEP or IGES format, together with 2D engineering drawing marked with dimensions, tolerances, material and surface treatment requirements. If you do not have finished 2D drawings, you can send us 3D model and simple description of your requirements. Our engineers will check the manufacturability and give a formal quotation.
Q2: How long will it take to receive your quotation after I send the drawings?
A2: For simple parts, we can send the quotation within 24 working hours. For complex multi-feature parts or projects with strict tolerance and special surface treatment requirements, it usually takes 2–3 working days for DFM analysis and cost calculation. We will inform you promptly if extra evaluation time is needed.
Q3: What is DFM analysis, and will you provide it for my project?
A3: DFM stands for Design for Manufacturability. Our engineers will review your drawing to find potential manufacturing risks, such as thin wall deformation, hard-to-machine corners, unreasonable tolerance settings. We will provide optimization suggestions to reduce machining difficulty, lower cost and shorten lead time. DFM check is free for our customers.
Q4: Can you modify my part design based on DFM suggestions?
A4: We can provide professional design advice, but we will not modify your CAD files without your permission. We will list all suggested changes in the DFM report. Once you confirm the adjustments, you can update your drawings, or we can help revise the model under your authorization.
Q5: What factors will affect the quotation price of CNC machined parts?
A5: The price is determined by material, part complexity, required tolerance, surface finishing, quantity and inspection requirements. Complex 5-axis parts, tight tolerance and special material will raise the cost. Higher order quantity can reduce the unit price for mass production.
Q6: Is the quotation valid for a fixed period?
A6: Yes. Our formal quotation is normally valid for 30 days. The price is subject to raw material market fluctuation. If you place the order after the expiration date, we will recheck the material cost and update the quotation accordingly.
Frequently Asked Questions
Q1: Do you provide free samples?
A1: We can provide existing samples from our shelf for reference, but custom samples based on customer drawings require sample tooling and machining cost. The sample fee can be refunded when your order reaches a certain quantity.
Q2: How do you pack the finished CNC parts?
A2: Each part is individually wrapped with anti-rust paper or EPE foam, then packed in a sturdy export carton. For fragile or precision parts, we use wooden cases. Special packaging requirements are also acceptable.
Q3: Can you provide material certificates (Mill Test Certificate)?
A3: Yes. We can provide material certificates from the mill, such as SGS or material test report (MTR), upon your request. The certificate is available for most metal materials including aluminum, stainless steel and brass.
Q4: What is your tolerance standard?
A4: We generally follow ISO 2768 medium tolerance. For parts with special requirements, we can achieve tighter tolerance according to your 2D drawing. Critical dimensions will be inspected 100% before shipment.
Q5: How long does it take to get a quote?
A5: For simple parts, we can quote within 24 hours. For complex parts or those requiring special surface treatment, quotation usually takes 1–2 working days. We will inform you in advance if more time is needed.
Q6: Can you help optimize my design to reduce cost?
A6: Yes, we offer free DFM (Design for Manufacturing) feedback. Our engineers will review your drawing and suggest improvements on wall thickness, corner radius, tolerance and machining process to lower the cost without compromising quality.
Q7: What if the parts don't match my drawing after delivery?
A7: We take full responsibility for any dimensional deviation caused by our machining process. We will remake or refund the defective parts, and cover the shipping cost. Each order goes through our QC process before shipment to prevent this from happening.
Q8: Do you accept small order quantity?
A8: Yes. We accept prototype orders from 1 piece. For mass production, there is no strict MOQ, but unit price is more favorable with larger quantity. We support both R&D prototyping and mass production.
Q9: Can you do special colors on anodized aluminum?
A9: Yes. We offer standard anodized colors including black, natural silver, blue, red and gold. Special colors are available upon request, but a minimum quantity may apply. Color consistency will be confirmed before batch production.
Q10: Is my drawing and design safe with you?
A10: Absolutely. We can sign an NDA (Non-Disclosure Agreement) before you share drawings. All customer designs and files are kept confidential and will not be disclosed to any third party.
Q11: What is your production capacity per month?
A11: We have multiple CNC machining centers, turning centers and grinding machines. Our monthly capacity can support both prototype runs and medium-to-high volume production. We will confirm the lead time based on your order quantity.
Q12: Can you machine parts with inserts or overmolding?
A12: We mainly focus on CNC machining of single material parts. Insert overmolding and secondary assembly can be coordinated with our partner factories. Please share your drawing and we will advise the best solution.
Q1: What is 5-axis CNC machining?
A1: 5-axis CNC machining is an advanced precision manufacturing process that allows the cutting tool or workpiece to move simultaneously along five axes, including three linear axes and two rotary axes. Unlike traditional 3-axis machining limited to flat and simple features, 5-axis technology enables one-setup processing of complex 3D curved surfaces, oblique holes, deep cavities and irregular geometries. It is the ideal solution for high-precision industrial components that require high accuracy and smooth surface quality.
Q2: What are the key advantages of 5-axis machining over 3-axis machining?
A2: The biggest advantage of 5-axis machining is one-clamp multi-angle processing. It eliminates repeated fixturing, greatly reduces cumulative positioning errors, and avoids machining dead angles. Compared with 3-axis machining, it delivers higher dimensional accuracy, better surface finish, improved batch consistency, and shorter lead times. For complex thin-wall and curved parts, 5-axis machining also effectively reduces tool vibration and part deformation, significantly lowering defect rates.
Q3: What types of parts require 5-axis CNC machining?
A3: 5-axis machining is required for any component with complex multi-directional features that cannot be completed efficiently with 3-axis machining. Typical parts include thin-wall curved components, multi-angle hole manifolds, deep cavity fixtures, asymmetric structural parts, and 3D profiled components. It is widely used in robotics, semiconductor equipment, aerospace systems, medical devices, optical instruments and automation machinery.
Q4: What tolerance can your 5-axis CNC machining achieve?
A4: Chenrong Precision stably achieves standard precision tolerance of ±0.005 mm for 5-axis machined parts. For high-end applications in semiconductor, medical and aerospace industries, we adopt stress-relief machining, custom fixture support and finish trimming processes to strictly control flatness, parallelism, concentricity and hole position accuracy, meeting ultra-precision assembly and testing requirements.
Q5: Is 5-axis machining more expensive than 3-axis machining?
A5: For simple flat parts, 3-axis machining is more cost-effective. For complex multi-feature parts, 5-axis machining provides better overall economy. It saves repeated tooling, secondary processing and manual calibration, greatly reducing rework and failure risks. Although the unit machining cost is slightly higher, it ensures stable quality, fewer defects and faster delivery, bringing higher comprehensive value for precision projects.
Q6: Do you offer 5-axis prototyping and mass production services?
A6: Yes. We provide full-lifecycle 5-axis CNC services, including rapid prototyping, small-batch validation and mass production. Our engineering team offers professional DFM analysis before production to optimize part structure and improve manufacturability. All finished parts support full CMM dimensional inspection, material certification and customized surface treatment, fully meeting industrial batch delivery standards.
Q1: What kinds of surface finishing do you provide for CNC machined parts?
A1: We provide a full range of industrial-grade surface treatments for custom metal and plastic CNC parts. Our available services include sandblasting, natural anodizing, colored anodizing, hard anodizing, mechanical polishing, mirror polishing, stainless steel passivation, electroplating, PTFE coating and ultrasonic cleaning. All finishing processes strictly follow international industrial standards to meet functional anti-corrosion requirements, precision assembly standards and cosmetic appearance needs for automation, semiconductor and medical equipment components.
Q2: What is the difference between natural anodizing and colored anodizing?
A2: Natural anodizing creates a transparent oxide protective layer on aluminum surfaces, effectively improving surface hardness, wear resistance and corrosion resistance while retaining the original metallic texture of the part. Colored anodizing provides customizable colors including black, silver, blue and red based on the same protective anodizing process. Natural anodizing is widely adopted for functional industrial precision parts, while colored anodizing is more suitable for equipment exterior components requiring aesthetic effects.
Q3: Do stainless steel parts need surface treatment?
A3: Yes. Although stainless steel features inherent corrosion resistance, CNC machining will leave tiny tool marks, surface stress and residual iron particles. Professional passivation treatment can remove surface impurities, eliminate processing residues and enhance oxidation resistance to prevent rust spots. For high-standard semiconductor, vacuum and medical components, we also provide ultra-fine polishing and particle-free cleaning to meet strict clean environment requirements.
Q4: Can you provide mirror polishing for metal CNC parts?
A4: Absolutely. We support high-precision mirror polishing for aluminum, stainless steel and copper components. This process completely removes tool lines, surface scratches and tiny flaws, delivering ultra-smooth surface texture and high reflectivity. Mirror polishing is commonly applied to fluid channel parts, optical fixtures and high-end equipment structural components to reduce fluid resistance and improve overall surface cleanliness.
Q5: Will surface treatment affect part tolerance and assembly accuracy?
A5: Low-impact treatments including passivation, ultrasonic cleaning and sandblasting will not change part dimensions. For coating processes such as anodizing and electroplating that generate thin surface layers, our engineers will reserve precise coating tolerance during CNC machining. All finished parts maintain standard dimensional accuracy and 100% assembly compatibility after surface finishing.
Q6: Can you customize special surface treatment for medical and semiconductor parts?
A6: Yes. We offer professional customized surface solutions for high-end industry components. We provide medical-grade passivation, oil-free degreasing, ultra-clean particle-free cleaning and low-residue surface treatment services. All processes strictly control surface burrs, residual oil and micro-particles, fully adapting to clean room working environments and high-precision equipment assembly standards.
Q1: What tolerance can Chenrong Precision achieve for CNC machined parts?
A1: Our standard CNC machining tolerance can reach ±0.01mm for most metal and plastic components. For ultra-precision parts processed on 5-axis machines, we can maintain a tolerance of ±0.005mm. The final achievable accuracy is affected by material properties, part geometry, machining method and size. Our engineering team will confirm feasible tolerance together with you during quotation.
Q2: What is the difference between general tolerance and tight tolerance?
A2: General tolerance is the default dimensional deviation for conventional non-critical features, which is cost-effective and meets most ordinary mechanical assembly requirements. Tight tolerance refers to stricter dimensional limits, which requires specialized tooling, multiple inspection steps and stable machining processes. Tight tolerance parts are usually used for semiconductor, optical and medical equipment, and will bring higher production cost and longer lead time.
Q3: Will material selection affect the tolerance of CNC parts?
A3: Yes. Different materials have different cutting characteristics and thermal expansion rates. For example, aluminum is easy to machine but prone to thermal deformation. Stainless steel and titanium alloy have high hardness, which requires slower cutting speed. Plastic materials such as PTFE and PA are easy to deform during processing. Our engineers will adjust machining parameters to minimize deformation and guarantee tolerance according to the selected material.
Q4: How do you control tolerance during mass production?
A4: We carry out multi-stage inspection for mass production. First, the first article inspection is done before batch production to verify all dimensions. In the production process, we perform periodic sampling inspection. After machining, key dimensions are checked by calipers, micrometers or CMM coordinate measuring machine. Full inspection is available for high-precision parts to ensure all products stay within the required tolerance range.
Q5: What should I do if my drawing has undefined tolerance?
A5: If your engineering drawing does not specify tolerance requirements, we will follow ISO 2768 standard as the default general tolerance. Before production, our engineer will check your drawing and point out the undefined tolerance features. We will confirm the tolerance standard with you to avoid any discrepancy in finished parts.
Q6: Can you adjust tolerance according to my application?
A6: Yes. We can optimize tolerance settings based on your actual assembly and working conditions. For non-critical features, we can relax tolerance appropriately to reduce cost and shorten lead time. For core matching features, we will maintain tight tolerance to guarantee assembly performance. Our DFM review will provide professional tolerance suggestions for your project.
Q1: How can I get a quotation for CNC machined parts?
A1: Please send us your 2D/3D CAD drawings (STEP, IGS, PDF) and requirements including material, tolerance, surface treatment, quantity and application. Our engineering team will evaluate and provide the quotation within 1-3 working days. We can sign NDA to protect your design confidentiality.
Q2: What materials can you process for CNC machining?
A2: We mainly machine aluminum alloy, stainless steel, brass, titanium alloy and engineering plastics. We will recommend the most suitable material according to your working conditions.
Q3: What is your tolerance capability?
A3: Normal tolerance can reach ±0.01mm, critical features can achieve ±0.005mm. Surface roughness can be Ra0.1~Ra3.2 as required.
Q4: What surface treatments do you provide?
A4: Anodizing, sandblasting, polishing, passivation, plating, powder coating and other custom surface finishes are available.
Q5: What is your MOQ and lead time?
A5: MOQ starts from 1 piece for prototype. Prototype lead time is 3-7 days, mass production lead time depends on quantity, normally 7-15 working days.
Q6: How do you guarantee product quality?
A6: We conduct full dimensional inspection with CMM, calipers and roughness tester before shipment. Inspection reports can be provided upon request.
Q7: What payment terms do you accept?
A7: We accept T/T, PayPal, Western Union. Normally 30% deposit, balance before shipment.
Q8: Can you do OEM & ODM CNC machining?
A8: Yes. We support OEM and ODM service. We can optimize your design for better manufacturability.
Q9: How about shipping?
A9: We can ship by DHL, FedEx, UPS, TNT or sea freight according to your requirement.
I. Basic Understanding
1. What is Aluminum Die Casting?
Aluminum die casting is a precision metal forming process. It involves injecting molten aluminum alloy into a pre-designed metal mold (die casting mold) under high pressure. After the alloy cools and solidifies, the mold is opened to remove the formed workpiece. Its core characteristics are high pressure (usually 10-150MPa) and high speed (filling speed up to 0.5-50m/s), enabling mass production of high-precision, complex-structured aluminum parts.
2. What are the core differences between aluminum die casting and other casting processes (such as sand casting and gravity casting)?
The core differences lie in forming pressure, precision, and efficiency:
• Pressure and Filling: Aluminum die casting uses high-pressure forced filling to fill complex cavities; sand casting and gravity casting rely on natural gravity filling, suitable for parts with simple structures.
• Precision and Surface Quality: Aluminum die castings have small dimensional tolerances (IT8-IT12) and low surface roughness (Ra1.6-6.3μm), requiring no extensive subsequent processing; sand castings have low precision and rough surfaces, needing multiple grinding processes.
• Efficiency and Batch Production: Aluminum die casting is suitable for mass production (single mold cycle as short as a few seconds to tens of seconds); sand casting has low mold costs but low production efficiency, suitable for small-batch, customized products.
3. What are the main advantages and limitations of aluminum die casting?
Advantages:
• Lightweight: Aluminum alloy has a low density (2.7g/cm³), about 35% lighter than steel, suitable for weight-sensitive scenarios (e.g., automotive, aerospace).
• High Strength: Through alloy proportioning and heat treatment, high strength and hardness can be achieved to meet the needs of structural parts.
• Precision Forming: Complex structures (such as holes, grooves, threads) can be integrally formed, reducing assembly processes.
• Cost-Effectiveness: Low unit cost in mass production with high material utilization rate (usually 80%-95%).
Limitations:
• High Mold Cost: Metal molds have a long manufacturing cycle (weeks to months) and high cost, not suitable for small-batch production (less than 1,000 pieces).
• Wall Thickness Limitation: Generally suitable for parts with a wall thickness of 0.5-5mm; excessive thickness is prone to shrinkage and porosity defects.
• Welding Difficulty: Some die castings have many internal pores, which may cause cracks and pores after welding, requiring special welding processes.
II. Process and Technology
1. What are the main types of aluminum die casting processes? What are their applicable scenarios?
• High-Pressure Die Casting (HPDC): The most mainstream process, featuring high-pressure and high-speed filling. Suitable for mass production of small and medium-sized precision parts (e.g., automotive transmission housings, electronic device casings), accounting for over 80% of total aluminum die castings.
• Low-Pressure Die Casting (LPDC): With low pressure (0.02-0.15MPa) and stable filling, it has fewer porosity defects. Suitable for producing high-quality, complex-loaded parts (e.g., engine cylinder heads, wheel hubs).
• Gravity Die Casting: Relies on gravity for filling, with lower mold costs than HPDC. Suitable for medium-batch, simple-structured parts (e.g., radiators, brackets).
2. What is the typical process flow of aluminum die casting?
Core Process: Mold Design and Manufacturing → Aluminum Alloy Melting (controlled temperature: 650-700℃) → Mold Preheating (150-300℃ to prevent rapid alloy cooling) → High-Pressure Filling (injecting molten aluminum alloy into the cavity) → Pressure Holding and Cooling (maintaining pressure until alloy solidification) → Mold Opening and Part Removal → Deburring/Flash Removal → Heat Treatment (optional) → Surface Treatment (optional) → Quality Inspection → Finished Product.
3. What are the common defects of die castings? How to avoid them?
• Porosity: Caused by gas absorption during alloy melting and excessive filling speed. Prevention methods: Degassing during melting (introducing nitrogen/argon), controlling filling speed, and optimizing mold venting channels.
• Shrinkage/Shrinkage Porosity: Caused by uneven cooling speed and insufficient pressure holding. Prevention methods: Optimizing the mold cooling system, extending pressure holding time, and adjusting alloy composition.
• Burrs/Flash: Caused by excessive mold clearance and insufficient clamping force. Prevention methods: Increasing clamping force, trimming the mold to adjust clearance, and optimizing die casting parameters.
• Cracks: Caused by improper alloy composition, rapid cooling speed, and unreasonable part structure. Prevention methods: Selecting appropriate aluminum alloy grades, optimizing mold cooling, and avoiding sharp corners/sudden wall thickness changes of parts.
III. Material Selection
1. What aluminum alloy grades are suitable for die casting? What are their characteristics and applications?
• ADC12 (Japanese standard, corresponding to domestic YL113): High silicon content (10%-13), excellent fluidity and formability, suitable for complex-structured parts (e.g., mobile phone middle frames, toy parts), but average corrosion resistance and medium strength.
• A380 (American standard): Excellent comprehensive performance, balanced fluidity, strength, and corrosion resistance, suitable for automotive parts (e.g., transmission housings, engine brackets) and industrial equipment accessories.
• A356 (American standard): High-purity aluminum alloy with high strength and good corrosion resistance. Its mechanical properties are significantly improved after T6 heat treatment, suitable for load-bearing parts (e.g., engine cylinder heads, wheel hubs).
• ADC10 (YL112): Performance similar to ADC12, slightly lower silicon content, and better toughness, suitable for complex parts with certain toughness requirements.
2. How to select the appropriate aluminum alloy grade according to product requirements?
Core Principle: Comprehensive judgment based on the product's force-bearing conditions, corrosion resistance requirements, structural complexity, batch quantity, and cost:
• Complex structure, mass production, low cost: Prioritize ADC12/A380 for good fluidity and easy forming.
• Complex force-bearing, high reliability: Select A356, whose strength meets structural part requirements after heat treatment.
• Corrosion-resistant scenarios (e.g., outdoor equipment): Optional A380 or special corrosion-resistant aluminum alloy, combined with surface treatment.
• Lightweight + high toughness: Low-silicon aluminum alloy or composite aluminum alloy materials can be used.
IV. Applications and Post-Treatment
1. In which industries are aluminum die castings mainly used?
Widely used in various fields:
• Automotive Industry
