How to Choose the Best Materials for CNC Parts:The Ultimate Material Guide for 2025

CNC parts' strength, service life, corrosion resistance, and ultimate cost are fundamentally determined by a seemingly minor decision: material selection. Inappropriate material selection can make your product indestructible in harsh environments or unnecessarily increase your budget due to excessive performance.

Have you ever been confused about the wide range of material options when you initiate a quotation through the CNC machine online platform? How does one find that one and only "golden key" for the custom machined parts?

The following guide will serve as your 24/7 materials consultant, taking deep dives into the selection logic from high-strength aluminum alloys to specialty engineering plastics, showing how JS Precision's CNC machining services translate materials science into your competitive advantage.

Figure 1: The rotating drill bit is drilling silver metal workpieces on the CNC machine.

Key Answers Summary

Materials Selection DecisionDimensions	Common Challenges and Pitfalls	JS Precision's Solutions
Performance Matching Applications	Excessive or insufficient material performance. Neglect environmental factors, such as temperature, medium.	Our experts draw on data to provide professional recommendations on material selection for different application scenarios-structural parts, appearance parts, and functional testing-to determine the best performance and cost matching.
Design for Manufacturability (DFM)	Many complicated designs use difficult-to-machine materials without considering the deformation of heat treatment.	We provide free DFM analysis for all CNC machining parts, proposing optimization solutions to the material selection so as to improve yield and reduce costs.
Cost and Supply Chain	Focusing only on material unit prices and ignoring overall processing costs and delivery time.	Our open CNC machine online pricing system displays in clear detail how we bill material and processing so it leverages our supply chain advantages to provide you with cost-effective options.

CNC Part Material Selection Challenges? JS Precision's Ultimate Guide To Solving Your Problems

With more than 15 years of practical experience in CNC machining, JS Precision has earned several certifications:

ISO 9001 Quality Management System Certification, AS9100 Aerospace Quality Management System Certification, and ISO 13485 Medical Device Quality Management System Certification. We have served more than 5000 clients across over 20 major industries, including the aerospace, medical, and consumer electronics industries.

For instance, in solving the machining problems of titanium alloy TC4 engine components for a top 5 global aerospace parts supplier, by optimizing the cutting parameters, we increased the machining efficiency by 30%, with a batch pass rate of over 99.8%.

In customizing 316L stainless steel conveyor components for a well-known food machinery brand, we strictly followed FDA standards, controlling the machining accuracy within ±0.005mm and have so far maintained a supply record with no complaints for three years.

The guide is based on these real-life cases and accumulated technical experience. Each recommendation has been tested in practice, and you can be sure it will help you when dealing with selecting materials for your CNC parts.

Want to quickly determine the suitable materials for your CNC parts? Please provide the application scenario and performance requirements of the parts, and our engineers will give free guidance on material selection, helping you avoid pitfalls.

How To Match Your CNC Parts Material To The Application's Demands?

The key question when choosing materials for CNC parts in an application would be, "What does this part need to do?" Only by clearly defining the core requirements of the application can a fitting material be selected. We analyze below the needs of different fields.

The Pursuit of High Strength and Lightweight: Aerospace and Robotics

In aerospace and robotics applications, parts must balance high strength with lightweight design to economize on energy consumption. A comparison of commonly used materials is as follows:

Material	Strength (MPa)	Strength-to-weight ratio	Cost (USD/lb)	Machinability
7075-T6 Aluminum alloy	503	210	3.5-5.0	Good
Titanium alloy TC4	860	270	30-45	Poor
Magnesium alloy	276	180	8-12	Average

7075-T6 aluminum alloy is highly cost-effective, suitable for cost-sensitive high-strength applications. Titanium alloy TC4 has the best performance but is costly and difficult to process, suitable for extreme conditions. Magnesium alloy excels in lightweight design but has slightly lower strength, suitable for parts with extremely high weight requirements.

Corrosion Resistance and Hygiene Safety: The Ironclad Rule for Medical and Food Grades

The medical and food industries have very high requirements for corrosion resistance and hygiene safety of parts, and the preferred materials are 316L stainless steel, anodized aluminum-silicon-magnesium alloy, and PEEK.

316L contains molybdenum and is corrosion-resistant and biocompatible, thus, it is suitable for surgical instruments. The sterilization resistance of anodized aluminum-siliconmagnesium alloy is quite good, and cleaning is convenient, hence, it is suitable for food equipment supports. PEEK has good chemical corrosion resistance and resistance to repeated sterilization.

Appearance, Thermal Conductivity, and Cost: Balancing Consumer Electronics

Consumer electronics components have to find a balance between aesthetics, thermal conductivity, and cost.

Anodized 6061 aluminum alloy displays color and has good thermal conductivity, suitable for mobile phone frames, brass has a rich, quality feeling, with excellent thermal conductivity but is expensive, suitable for high-end headphone casings.

ABS plastic is inexpensive and easy to process. Its thermal conductivity is poor, but it is suitable for parts with low thermal conductivity requirements such as keyboard covers.

Figure 2: A quick reference chart for properties of common materials used in CNC machining.

How Do Professional CNC Machining Services Tame Challenging Materials?

Once the problem of material matching application has been resolved, professional CNC machining services become particularly vital when tackling difficult-to-machine materials. JS Precision's capability of CNC machining services is reflected in its ability to transform "tough nuts to crack" into precision parts.

Overcoming the "Tool Sticking" Problem: Machining Strategies for Stainless Steel and Titanium Alloys

The stainless steel and titanium alloys are prone to "tool sticking" and work hardening during machining.

We will use sharp geometric angled tools combined with high-pressure coolant to reduce friction for timely heat dissipation and prevent tool sticking. We also optimize the cutting parameters, like reducing the cutting speed while increasing feed rate, which is very effective in alleviating the hardening problem.

Thermal Management Master: Secrets to Machining High Thermal Conductivity Materials such as Copper and Aluminum

When machining a high thermal conductivity material like copper and aluminum, heat can easily cause the thermal expansion of the parts, affecting the accuracy. We control heat through multiple small-depth cuts and use specialized cutting fluid for rapid cooling to prevent thermal expansion from causing dimensional instability.

Micron-level Sculpting of Brittle Materials: Precision Milling of Ceramic and Glass Fiber Composites

These ceramic and glass fiber composites are brittle and apt to break during the machining process. To minimize the effects of the cutting force applied, we use an ultra-high-speed spindle with 40,000 rpm for reduced impact and sharp, rigid micro-tools, and special clamps hold the parts, preventing wobbling during manufacturing.

Have an "tool sticking" problem when machining with difficult-to-machine materials like stainless steel and titanium alloys? Contact our CNC machining services team immediately, provide your part specifications, and we will offer a tailored machining strategy for the workpiece, mitigating the risk of work hardening.

What Are The Crucial Material Considerations For Intricate CNC Machining Parts?

While the designs become complicated, the materials to be selected for the CNC machining parts must be done with much caution, always thinking about potential problems that might occur during machining. The following are key considerations.

Thin-Walled Structures: Materials Required to Provide High Specific Stiffness

In the machining process of thin-walled CNC machining parts, materials with high specific stiffness are required.

The 7075 aluminum alloy has a high value of specific stiffness and thus does not easily deform after machining. It is ideal for use in small thin-walled supports. PEEK has good rigidity and light weight, so it is suitable for lightweight thin-walled parts, ensuring the success rate of machining and stability.

Internal Stress and Deformation: The Value of Pre-hardened Steel and Stress-Relieving Profiles

For complex cavity CNC machining parts, if the material has high internal stress, it is easily deformed after machining.

Using materials that are pre-hardened, such as P20 mold steel, can release internal stress, thus causing less deformation in machining, another method is to select a stress-relieving blank to reduce post-machining deformation and ensure accuracy.

Deep Holes and Slender Features - Challenges in Chip Removal and Tool Life

For deep holes or slender features in CNC machining parts, chip removal and tool life are very important. Copper has good chip removal, is less prone to chip clogging when machining deep holes, and has low tool wear, steel has slightly poorer chip removal, requiring chip removal devices and wear-resistant tools to extend tool life.

How Does Material Feasibility Analysis Empower Your Custom Machined Parts?

The success of custom machined parts starts with comprehensive manufacturing feasibility analysis. JS Precision secures the production of custom machined parts through professional material feasibility analysis.

From "Machinable" to "Easy to Machinable": Our DFM Philosophy

Our philosophy in DFM is to change custom machined parts from "machinable" to "easy to machinable."

For example, if a customer's part contains internal right angles that are challenging to machine, we would recommend changing the fillets to rounded corners and harder, more wear-resistant steel. This increases the durability of the part while decreasing the difficulty of machining.

Pre-assessment on Risks of Heat Treatment - Avoiding Deformation and Cracking

Heat treatment can also deform or crack custom machined parts, a factor we consider during the design process. For example, if a customer wants to carburize and quench complex parts, we suggest nitriding, since the deformation amount caused by it is low and can maintain the precision of the parts, especially for those with high risks.

Material Substitution Recommendations: Bridging Performance and Cost

We can propose material substitutions for custom machined parts, such as using free-machining stainless steel instead of regular materials, to decrease machining difficulty and cost by 15% while keeping core performance and reducing machining time by 30%.

How To Balance Material Cost And Performance In Low-Volume CNC Prototyping Services?

The core of the low-volume CNC prototyping services is to obtain the most effective verification result at the most economical cost. Low-volume CNC prototyping services offered by JS Precision will be able to help you balance material cost and performance.

Separation of Form and Function: Different Material Selections for Different Verification Objectives

We will suggest materials for the low-volumes CNC prototyping services according to the purpose of verification.

If verification is just for component assembly, then a low-cost material can be used, such as 6061 aluminum alloy or ABS plastic, which saves up to 40% cost.

If for functional test purposes, materials with equivalent or similar performance to mass production should be chosen. For instance, using 7075 aluminum alloy for mass production, the prototype is also suggested to use the same material for accurate test results.

The Clever Use of Non-Metallic Materials: Fast and Inexpensive Initial Verification

Non-metal materials used in low-volume CNC prototyping services include the following:

ABS plastic is an economical option at just $2-3 per pound, and jobs can be processed rapidly, making it suitable for proof-of-concept. Nylon has good toughness, suitable for testing the impact resistance of parts. Delrin has good wear resistance, suitable for testing friction performance of moving parts.

Our Seamless "Prototype to Production" Path

The equipment in our low-volume CNC prototyping services is the same as that used in mass production, and the standards of processes are also identical.

For example, the machining centers used for prototypes are the same as those utilized in mass production, and the parameters in cutting are also maintained the same. Therefore, data obtained in the prototyping stage can be directly applied to mass production, and unexpected problems in mass production can be avoided.

Want to do small-batch CNC prototyping? Please tell us the verification purpose, and we can give you material selection and cost estimates, which enable you to complete verifications with a reasonable cost by using our low-volume CNC prototyping services.

Figure 3: Thermoplastic is the most widely used type of plastic in CNC machining, including ABS, nylon, and others.

What Materials Are Supported By A Leading CNC Machine Online Platform?

A good CNC machine online platform should offer a rich selection and guidance with respect to materials, much like expert support offline. JS Precision's CNC machine online platform has significant advantages in material support.

Vast "Digital Material Library": Over 100 Selectable Materials

Our CNC machine online platform uses a "digital material library" with more than 100 materials. It ranges from standard Q235 steel and 6061 aluminum alloy to special titanium alloys, such as TC4 and Hastelloy, and engineering plastics like PEEK and Nylon, all standard grades included for the fulfillment of various industries.

Intelligent Material Selection Assistant: Offering Suggestions Based on Your Input

The intelligent material selection assistant on the platform is very useful.

Input the key performance requirements of your parts on the CNC Machine Online platform, such as a strength of 500MPa and temperature resistance over 200°C, and add that it should be corrosion-resistant. It will quickly filter and recommend 3-5 of the most suitable materials, explaining the advantages and disadvantages of each.

Real-time Price and Inventory Visibility

After choosing materials in the CNC Machine Online system, it will update quotes in real time. For example, choosing material 6061 aluminum alloy will show a processing material price of $3.5 per pound.

At the same time, it will also show the inventory status: when there is sufficient inventory, it will mark "Available for shipment within 3 days", if the inventory is in short supply, it will mark "Restocking in 7 days," thus enabling you to accurately plan the timeline for your project.

Want to rapidly select suitable materials on the CNC Machine Online platform? Log in to the platform, enter your part performance requirements, and let the intelligent assistant recommend materials. You can also view prices and inventory in real time.

What Are The Optimal Surface Treatment Options For Your Custom CNC Aluminum Parts?

Surface treatment gives custom CNC aluminum parts their "second life". Different surface treatments give custom CNC aluminum parts different properties. Some common options are compared below:

Anodizing

Anodizing is divided into hard and ordinary types: Hard anodizing film thickness up to 50μm, wear-resistant and meets military standards, suitable for mechanical parts casings, ordinary anodizing film thickness is 5-20μm, dyed, highly decorative, suitable for mobile phone frames and other exterior parts.

Chemical Nickel Plating

It does not use electricity in chemical nickel plating, the complex internal cavities of custom CNC aluminum parts can form a uniform protective layer. Hardness can reach HV500 or more and it is resistant to corrosion, making it suitable for the precision connectors of complex internal cavities and therefore avoiding uneven electroplating problems.

Sandblasting and Passivation

Sandblasting gives the custom CNC aluminum parts a fine sand or matte finish to improve their appearance. Chemical passivation will create a transparent protective film that provides corrosion resistance without affecting the appearance, this is suitable for those parts, like equipment panels, which require corrosion protection and good appearance.

Want to choose the optimal surface treatment for your custom CNC aluminum parts? We'll recommend suitable solutions based on the application scenario and performance requirements of your parts while providing a sample of the treated parts for reference.

Figure 4: Surface treatment is crucial for aluminum products produced by CNC machining, as it can significantly improve their corrosion resistance, wear resistance, and environmental adaptability.

Practical Case-The 40% Weight Reduction: Material Innovation In A UAV Component

Customer Objective

The servo motor housing is one of the key CNC parts for flight control in drones, necessary for a drone company specializing in R&D of industrial-grade drones.

• The original design adopted 6061-T6 aluminum alloy and weighed 250g, which could not meet the requirement of less than 150g for the new model.
• Previously, the company tried to reduce the wall thickness to 1.2mm to reduce the weight, but during the vibration test, the part broke and could not withstand the requirements for anti-vibration resistance to fly.
• While direct replacement with 7075-T6 aluminum alloy meets the strength requirement, it increases the cost by 25%. There is excessive performance in some areas where the wall is thin.

JS Precision Solution:

Material Redefinition:

We recommend aerospace-grade aluminum-silicon-magnesium alloy 6082-T6. The strength of the alloy is close to 7075-T6, 18% lighter in weight compared with 6061-T6, and its price is only 8% higher than that of 6061-T6, for a better balance among lightweight, strength, and corrosion resistance.

DFM Optimization:

Using ANSYS simulation software during the topology optimization phase to simulate the UAV flight and the resultant stress distribution on the servo housing, we accurately locate the area of stress concentration. Add ribs at the points of connection, increase the thickness from 2mm to 3mm, and decrease it from 1.5mm to 1mm in the low-stress side areas to further reduce weight.

Prototyping:

With the help of our Low-volume CNC prototyping services, 10 sets of newly designed custom CNC aluminum parts housings were manufactured within only 5 days. Besides routine strength testing, a 100-hour continuous fatigue test was conducted in order to ensure long-term stability.

Our Success Result

The final servo housing passed all functional tests, with the weight reduced to 150g, a successful weight reduction of 40%. The overall cost was 15% lower than using the 7075-T6 solution, saving approximately $2000. The customer immediately moved into small-batch production and supply is now stable.

Figure 5: CNC machining of aluminum alloy drone servo housing

FAQs

Q1: What is the biggest difference between aluminum, steel, and plastic when it comes to CNC machining?

Aluminum is easy to machine in CNC and lightweight and has good electrical conductivity, which makes it suitable to be used in lightweight parts. Steel is strong, though difficult and expensive to machine. Plastic is cheap but with poor mechanical properties, hence suitable for insulating parts.

Q2: I need my parts to withstand high temperatures (>200°C), what material would you recommend?

We recommend 316L stainless steel, which can withstand a temperature as high as 870°C and is corrosion-resistant, while titanium alloy can withstand a temperature up to about 600°C and it is of high strength, special engineering plastics PEEK can withstand a temperature up to 260°C and are lightweight. Choose according to your needs.

Q3: Why are there such large price differences between different materials when providing online quotes?

Price differences are due to raw material costs. For instance, titanium alloy raw material costs are 10 times higher compared with aluminum, and the different processing difficulties raise labor costs. Material wastage rates also affect, with more difficultly processed materials having higher wastage rates.

Q4: Is it possible to have my own material processed?

You can provide your own materials for processing, but to guarantee the quality, you need to provide material certification to prove the material composition and performance, we will charge a material verification and testing fee of $50-100 USD to avoid the processing risk.

Q5: Can plastic parts achieve the same precision as metal parts?

Similar accuracy can be achieved, but attention should be paid to the characteristics of the plastic, such as that Nylon is hygroscopic and should be dried before processing, or with high elastic recovery, its cutting parameters have to be optimized to get a dimensionally stable part.

Q6: Is there a difference in material selection between small-batch prototyping and mass production?

During prototyping, easily machinable materials can be selected to reduce costs-such as using ABS instead of mass-produced PEEK for proof-of-concept. If functional tests need to be performed, the selection of the material should be as close to mass production as possible to ensure that test data can inform and guide mass production.

Q7: Do your materials have certifications? e.g., aviation standards, medical

Yes, our materials meet multiple certifications: for example, the AMS standard in the aerospace field and the ISO 13485 standard in the medical field. We are also able to provide all material certification documents to meet industry requirements.

Q8: Why Select JS Precision as Your CNC Material and Machining Partner?

We have 15 years of experience and can provide a full-process service including material selection, machining, and surface treatment. We also have a professional team and a CNC machine online platform to help you reduce costs, increase efficiency, and ensure project quality.

Summary

Material is the soul of engineering, and the right choice is the starting point for superior performance and commercial success.

JS Precision is committed to being your most reliable manufacturing partner in helping you choose the right materials through expert CNC machining services, a comprehensive material library, and precise feasibility analysis, enabling your products to stand out from competitors.

Don't let material selection uncertainty hold back your innovation.

Experience technology-driven intelligent material selection and manufacturing now! Please visit the JS Precision official website, use our intelligent CNC machine online quotation platform, upload your CAD files, and explore our digital material library.

You will receive a comprehensive solution in hours, including optimal material recommendations, transparent pricing, and professional DFM analysis. Let's get started with the materials and create superior products together!