Nylon grades are selected in two steps: first choose the PA matrix, such as PA6, PA66, PA11, or PA12; then choose whether it remains unfilled or receives glass fiber, carbon fiber, impact, flame-retardant, wear, or other modification.
For the main commercial routes, unfilled PA is the baseline, GF20 adds moderate structural reinforcement, and CF30 targets higher specific stiffness or special electrical and dimensional requirements. The highest fiber percentage is not automatically the best grade.
Nylon Grade Selection at a Glance
| First Decision | Common Starting Point | Reason |
|---|---|---|
| General molded part | Unfilled PA6 or PA66 | Toughness, wear, and processing balance |
| Moderate deflection control | PA-GF20 | More stiffness with a broader balance than higher loading |
| Structural molded part | PA-GF30 | Common stiffness and dimensional-control route |
| High specific stiffness or ESD review | PA-CF30 | Weight, low CTE, or electrical formulation requirements |
| Wet dimensional service | PA12 or qualified modified grade | Lower moisture uptake |
The Nylon Family Overview
| Grade | Type | Melting Point | Moisture (50% RH) | Key Characteristic |
|---|---|---|---|---|
| PA6 | Aliphatic | 220°C | 2.7% | Toughness, processability |
| PA66 | Aliphatic | 260°C | 2.5% | Strength, heat resistance |
| PA11 | Bio-based | 185°C | 0.8% | Flexibility, low moisture |
| PA12 | Aliphatic | 178°C | 0.7% | Lowest moisture absorption |
| PA46 | Aliphatic | 295°C | 3.5% | Highest heat resistance |
PA6: The Versatile Workhorse
PA6 is the most widely used nylon grade, representing approximately 60% of nylon consumption. It offers an excellent balance of strength, toughness, and processability.
Key Properties
- Tensile strength: 70-85 MPa
- Excellent impact resistance
- Good surface finish and colorability
- Wider processing window than PA66
PA66: The High-Performance Standard
PA66 offers approximately 10-15% higher strength and stiffness than PA6, with superior heat resistance. It’s the preferred choice for demanding applications.
PA11 and PA12: The Specialty Nylons
PA11 and PA12 are distinguished by their exceptionally low moisture absorption—less than 1% even at saturation. This gives them outstanding dimensional stability.
PA46: The High-Temperature Specialist
PA46 (Stanyl) offers the highest heat resistance of any aliphatic nylon, with a melting point of 295°C.
Base Resin and Reinforcement Are Separate Decisions
PA6-GF20 and PA66-GF20 share the same glass percentage but not the same moisture response, melting range, heat capability, or processing window. The same applies to PA6-CF30, PA66-CF30, and PA12-CF30. Drawings and purchase orders should identify the complete matrix and modification package.
- Unfilled PA: prioritize toughness, fatigue, wear, surface quality, and easier processing.
- GF20: use when moderate stiffness and lower shrinkage are needed without moving directly to a higher glass loading.
- GF30: use for a common structural balance, with gate, weld-line, and warpage review.
- CF30: use when specific stiffness, low thermal expansion, weight, or an electrical target justifies the premium and processing controls.
Selection Guide
| Requirement | Recommended Grade |
|---|---|
| General purpose, cost-sensitive | PA6 |
| High temperature (>120°C) | PA66, PA46 |
| Wet/humid environment | PA12, PA11 |
| Maximum stiffness | PA66-GF30/50 |
Modified Nylon Grade and Supply Review
Nylon Plastic supplies unfilled and modified PA compounds, with primary article and product support centered on pure PA, PA-GF20, and PA-CF30 routes. Grade review should include the drawing, service conditions, required approvals, annual volume, color, and incumbent specification.
Common Nylon Grade Selection Mistakes
- Writing only “nylon” or “PA” on the drawing without identifying the matrix and modification.
- Comparing dry tensile values while the production part will operate in humid or conditioned service.
- Increasing fiber content before checking whether the real problem is geometry, gate position, weld lines, or creep.
- Choosing CF30 for maximum stiffness when a GF20 compound already meets the functional requirement at lower cost and processing risk.
- Assuming a flame, ESD, heat-stabilized, or approved formulation from the family name instead of the exact grade documentation.
Nylon Grade RFQ Checklist
A complete inquiry should identify the preferred PA matrix, reinforcement percentage, annual volume, drawing revision, color, molding process, service temperature, humidity, chemicals, impact, load duration, dimensional state, and regulatory requirements. Include the incumbent grade and failure mode when the request is a replacement project. This information allows the supplier to compare unfilled PA, GF20, GF30, and CF30 without relying on a generic strength ranking.
How Nylon Plastic Reduces Grade-Selection Risk
Buyers often receive quotations that list a resin family but omit the exact modification, conditioning state, or approval package. Nylon Plastic has worked across material modification and finished-product manufacturing since 2005, allowing one project review to connect grade selection with the intended molding, CNC, or 3D-printing route.
- Product focus: pure PA, PA-GF20, and PA-CF30 can be compared as distinct commercial routes.
- Custom compounding: formulation review is available when standard grades do not meet stiffness, impact, color, wear, flame, or dimensional requirements.
- Manufacturing feedback: gate direction, machining deformation, moisture conditioning, or print orientation can be considered before material approval.
- Buyer documentation: the RFQ can define TDS, COA, compliance, sample, incoming inspection, and lot-approval expectations before volume ordering.
Frequently Asked Questions
Should I choose PA6 or PA66 for injection molding?
PA6 often provides a broader processing window and good toughness, while PA66 is commonly selected for higher strength and thermal margin. Moisture, impact, geometry, approvals, and exact grade data can change the decision.
When should an unfilled nylon grade be replaced with GF20?
Consider GF20 when the unfilled grade cannot meet deflection, creep, shrinkage, or loaded-temperature targets. Validate impact, weld lines, warpage, surface appearance, and tool wear before approval.
What is the difference between GF20 and CF30 nylon?
GF20 uses approximately 20% glass fiber and is generally a more cost-effective moderate reinforcement. CF30 uses approximately 30% carbon fiber and targets higher specific stiffness, lower thermal expansion, or electrical behavior, depending on the formulation.
What must a nylon grade RFQ include?
Include the PA matrix, reinforcement or modification, drawing, volume, service temperature, humidity, chemicals, load, impact, tolerances, color, flame rating, and regulatory requirements.
Related Reading
- PA6 vs PA66: Which Nylon Grade Is Right for Your Application?
- PA6 vs PA12: Your Practical Guide to Nylon Material Selection
- Nylon 12 (PA12) — The Most Moisture-Resistant Engineering Nylon
Request a Nylon Grade Review
Send the drawing, current material, target properties, annual volume, and operating environment. We can compare the matrix and modification separately before recommending unfilled PA, GF20, GF30, or CF30.
