CNC Machining
Aluminum / Stainless / Carbon Steel / Copper & Brass / Engineering Plastics
View CNC Machining GuideMATERIAL SELECTION GUIDE
Material Selection Guide for Custom Manufacturing
Material selection should not rely on the material name alone. Manufacturing process, functional requirements, environment, critical dimensions, surface requirements and production needs should be reviewed together before a drawing moves into quotation.
MATERIAL FAMILIES
Material Families at a Glance
Use these six material families as starting points for custom manufacturing review. Each family should be evaluated against process route, function, surface requirements and project conditions.
ALUMINUM
Aluminum
Lightweight / CNC / Die Casting
Open GuideZINC ALLOYZinc Alloy
Die Casting / Compact Geometry / Surface
Open GuideSTAINLESS STEELStainless Steel
Corrosion / CNC / Stamping
Open GuideCARBON STEELCarbon Steel
CNC / Stamping / Surface Protection
Open GuideCOPPER & BRASSCopper & Brass
Conductivity / Turning / Connectors
Open GuideENGINEERING PLASTICSEngineering Plastics
Weight / Insulation / CNC / Injection Molding
Open GuideBUYER DECISION TABLE
Quick Material Comparison
This table is a practical comparison for early sourcing discussions. Final choice depends on grade, geometry, quantity, environment and drawing requirements.
| Material | Weight Consideration | Environment / Corrosion | CNC | Casting / Molding | Stamping / Forming | Functional Focus |
|---|---|---|---|---|---|---|
| Aluminum | Commonly reviewed where lower weight matters. | Depends on alloy, exposure and finish. | Common for housings, brackets and precision parts. | Common for selected die casting projects. | Selected sheet projects may be reviewed. | Weight, machinability and thermal applications. |
| Zinc Alloy | Usually reviewed for compact parts rather than lowest weight. | Surface finish and exposure should be reviewed together. | Secondary machining may be reviewed. | Common for zinc die casting. | Not the typical route. | Compact die cast geometry and surface finishing. |
| Stainless Steel | May be reviewed when metal weight is acceptable. | Commonly reviewed where corrosion exposure matters. | Depends on grade and feature requirements. | Not the usual selection route for this guide. | Common for selected sheet and stamping projects. | Corrosion, mechanical interfaces and surface condition. |
| Carbon Steel | May be reviewed when weight is not the main constraint. | Surface protection should be reviewed early. | Common for selected machined and turned parts. | Not the usual selection route for this guide. | Common for sheet, stamping and formed parts. | Mechanical use, cost review and surface protection. |
| Copper & Brass | Usually reviewed for function rather than lowest weight. | Depends on material, finish and service environment. | Common for selected machined and turned parts. | Not the usual selection route for this guide. | Project-specific sheet or formed parts may be reviewed. | Conductivity, connectors, fittings and bushings. |
| Engineering Plastics | Commonly reviewed for lower weight or insulation needs. | Depends on resin, chemical exposure and operating conditions. | Common for prototypes and precision plastic components. | Commonly reviewed for injection molding. | Not the typical route. | Weight, insulation, wear and special function. |
PROCESS ROUTING
Choose by Manufacturing Process
Material choice and process choice should be reviewed together. A material that works well in one route may not be suitable for another geometry, quantity or finish requirement.
Die Casting
Aluminum / Zinc Alloy
View Die Casting GuideInjection Molding
Engineering Plastics
View Injection Molding GuideMetal Stamping
Stainless / Carbon Steel / Copper & Brass / selected Aluminum
Explore Metal StampingSurface Finishing
Base material and finish must be reviewed together.
View Finishing GuideFUNCTIONAL REQUIREMENTS
Choose Materials by Functional Requirement
Functional needs often narrow material choices before detailed cost review. These are starting points for project-specific evaluation, not automatic selections.
Lower Weight
Aluminum or engineering plastics may be reviewed where part weight is a major concern.
Corrosion Exposure
Stainless steel, selected aluminum with finish or project-specific plastics may be reviewed depending on exposure.
Electrical Conductivity
Copper or brass may be reviewed where conductive function, contacts or terminals are part of the design.
Thermal Management
Aluminum or copper may be reviewed where heat transfer is a major application requirement.
Mechanical / Structural Use
Carbon steel, stainless steel or aluminum may be reviewed depending on geometry, load and environment.
Wear / Insulation / Special Function
Engineering plastics or selected metals may be reviewed depending on application and operating conditions.
MATERIAL TO PROCESS MATRIX
Material → Process Matrix
Use this matrix to screen process fit before detailed RFQ review. Final process suitability depends on material grade, geometry, quantity and drawing requirements.
Common — commonly reviewed manufacturing routeSelected — suitability depends on material, geometry and project requirementsSecondary — typically used after the primary manufacturing processProject Review — requires project-specific confirmation— — not a typical route for this material family
| Material | CNC | Turning | Die Casting | Injection Molding | Stamping / Forming |
|---|---|---|---|---|---|
| Aluminum | Common | Common | Common | — | Selected |
| Zinc Alloy | Secondary | Secondary | Common | — | — |
| Stainless Steel | Common | Selected | — | — | Common |
| Carbon Steel | Common | Common | — | — | Common |
| Copper & Brass | Common | Common | — | — | Project Review |
| Engineering Plastics | Common | Selected | — | Common | — |
Final process suitability depends on material grade, geometry, quantity and drawing requirements.
SURFACE COMPATIBILITY
Material Selection Does Not End with the Base Material
Surface appearance, protection, contact behavior and inspection expectations should be reviewed with the base material instead of being treated as a separate late-stage choice.
Aluminum
Anodizing / Powder Coating / Polishing
Zinc Alloy
Plating / Painting / Surface Preparation
Stainless Steel
Polishing / Brushing / Passivation Review
Carbon Steel
Plating / Painting / Powder Coating
Copper & Brass
Polishing / Tin Plating / Nickel Plating
Engineering Plastics
Surface requirements depend on resin and application.
SELECTION QUESTIONS
Before Choosing a Material, Review These 6 Questions
A short checklist helps buyers and engineers connect material selection with real part requirements before requesting a quote.
01
What does the part need to do?
02
Which manufacturing process fits the geometry?
03
What environment will the part operate in?
04
Which dimensions or interfaces are critical?
05
Is surface appearance or protection required?
06
Is this prototype, low-volume or repeat production?
MATERIAL GUIDES
Explore Every Material Guide
Move from a broad material family decision into grade-level and process-specific review when a project needs more detail.
Aluminum Material Guide
6061 / 6082 / 7075 / ADC12 / A380
Read GuideZinc Alloy Material Guide
Zamak 3 / Zamak 5 / Zamak 7
Read GuideStainless Steel Material Guide
303 / 304 / 316 / 17-4 PH
Read GuideCarbon Steel Material Guide
1018 / 1045 / SPCC / SECC
Read GuideCopper & Brass Material Guide
C110 / C360 / H59 / H62 / C260
Read GuideEngineering Plastics Guide
POM / PEEK / Nylon / PC / ABS
Read GuideFAQ
Material Selection FAQs
How do I choose a material for a custom manufactured part?
Start with the part function, manufacturing process, environment, critical dimensions, surface requirements and production needs. The material should be reviewed together with geometry and RFQ requirements.
Which materials are commonly used for CNC machining?
Aluminum, stainless steel, carbon steel, copper, brass and engineering plastics are commonly reviewed for CNC machining, depending on grade, geometry, tolerances and application requirements.
Which materials are commonly used for die casting?
Aluminum and zinc alloy are common material families for die casting review. Final selection depends on part size, geometry, production requirements, surface expectations and application conditions.
What materials are commonly used for metal stamping?
Stainless steel, carbon steel, copper and brass, and selected aluminum sheet materials may be reviewed for stamping or forming, depending on thickness, geometry, bends and surface requirements.
How should I choose between aluminum and stainless steel?
Aluminum may be reviewed where lower weight, machinability or thermal considerations matter. Stainless steel may be reviewed where corrosion exposure, strength or surface requirements are more important.
When should I consider engineering plastics instead of metal?
Engineering plastics may be reviewed where lower weight, insulation, wear behavior, chemical exposure or molded production needs are important. Material choice still depends on resin, geometry and operating conditions.
Does surface finishing affect material selection?
Yes. Surface finishing can affect appearance, protection, contact behavior and inspection expectations, so the base material and finish should be reviewed together early in the project.
What material information should I include in an RFQ?
Include the preferred material or material family, grade if known, application, quantity, critical dimensions, surface requirements and any environmental or functional requirements that affect selection.
RFQ PREPARATION
Not Sure Which Material Fits Your Part?
Share the drawing, application, quantity, critical dimensions and surface requirements so the manufacturing route and material options can be reviewed together for your project.
- drawing
- application
- quantity
- critical dimensions
- surface requirements