Short answer: Choose resin (SLA/DLP/LCD) when you need fine detail, smooth surfaces, or tight tolerances — typical for dental models, miniatures, jewelry, and prototypes that will be painted or molded. Choose nylon (SLS/MJF) when you need real mechanical strength, flexibility, heat resistance, or living hinges — typical for functional brackets, enclosures, gears, and end-use parts.
If you only need one or two aesthetic prototypes, resin is usually cheaper and faster. If the part must survive load, impact, or repeated motion, nylon is the safer default.
Side-by-Side Comparison
| Factor | Resin (SLA/DLP/LCD) | Nylon (SLS / MJF / FDM Nylon) |
|---|---|---|
| Best for | Detail, smoothness, visual models | Strength, flexibility, functional load |
| Typical accuracy | ±0.1–0.2 mm | ±0.1–0.3 mm (SLS/MJF) |
| Surface finish | Very smooth, layer lines nearly invisible | Slightly grainy (SLS) or smooth (MJF) |
| Tensile strength | 30–65 MPa (brittle) | 45–85 MPa (tough, can flex) |
| Heat resistance | 40–120 °C depending on resin | 110–180 °C depending on nylon type |
| Moisture sensitivity | Low (after full cure) | High — nylon absorbs water, changes dimensions |
| Post-processing | Wash + cure required | Media blast + dye optional |
| Material cost per liter/kg | $40–$150/liter | $60–$200/kg |
| Typical lead time | 1–3 days | 2–5 days |
Source context: Mechanical data is representative of common commercial photopolymer and PA11/PA12 materials. Always request a material datasheet for the exact resin or nylon grade your supplier uses.
When Resin Wins
- Visual prototypes and miniatures
- Layer height can go as low as 0.01–0.05 mm.
- Fine details like panel lines, text, and jewelry prongs survive.
- Dental and medical models
- Biocompatible resins exist (FDA-cleared for specific workflows).
- Gypsum-like and clear resins are standard for dental aligner thermoforming.
- Mold-making and investment casting
- Castable and burnout resins are widely used in jewelry and small metal casting.
- Tight internal channels or threads
- Resin prints holes and threads with less sag than fused-filament processes.
When Nylon Wins
- Functional brackets, clips, and housings
- Nylon withstands repeated flexure without cracking. A living hinge in nylon can survive thousands of cycles.
- Gears, snaps, and interlocking parts
- Toughness matters more than surface beauty.
- Heat-exposed or under-hood parts
- PA12 and glass-filled nylons handle automotive and industrial temperatures.
- Batch production of end-use parts
- SLS/MJF can nest many parts in one build, lowering per-part cost at volume.
Cost Reality Check
A common mistake is comparing resin vs nylon only by material price. The bigger cost drivers are:
- Failure rate: Brittle resin parts break during handling or shipping more often than nylon.
- Post-processing time: Resin needs washing, curing, and support removal. Nylon SLS parts need depowdering and media blasting.
- Dimensional rework: Nylon absorbs moisture and can swell ~0.5–1% over days in humid air. Resin can warp during cure if unsupported.
For a single prototype, resin is usually cheaper. For 10+ functional units, nylon often wins on total cost per usable part.
Quick Decision Tree
Need smooth surface or fine detail? → Resin
Need load-bearing or flexible part? → Nylon
Need heat resistance > 100 °C? → Nylon (PA12/GF) or high-temp resin
Need dental/medical visual model? → Resin (biocompatible grade)
Need batch production of end-use parts? → Nylon SLS/MJFGet Both Without Buying Printers
If you are unsure which process fits your part, you do not need to buy two printers. A domestic 3D printing service can run both SLA resin and SLS/MJF nylon samples from the same CAD file, so you can test fit, finish, and strength before committing to a batch. This is especially useful for medical-device prototypes that may later need ISO 13485 workflow documentation.
Need resin and nylon samples from one supplier? Our domestic 3D printing partners handle SLA/DLP resin, SLS/MJF nylon, and medical-grade workflows with material datasheets and inspection reports. Request a quote.
FAQ
Q: Can I paint or plate resin parts? A: Yes, after thorough cleaning and light sanding. Use a primer compatible with photopolymer resins; some solvents can craze the surface.
Q: Does nylon need to be dried before printing? A: For SLS/MJF the supplier handles powder conditioning. For FDM nylon you must dry filament at 70–80 °C; otherwise steam bubbles ruin layer strength.
Q: Is resin stronger than PLA? A: Some engineering resins are stronger than PLA in tension, but most are more brittle. Nylon is tougher than both in real-world impact and fatigue.
Q: Which is better for waterproof parts? A: Resin prints are naturally more water-resistant if post-cured properly. Nylon absorbs water, so sealed or coated nylon is usually needed for wet environments.
Q: How do I choose between standard and high-temp resin? A: High-temp resins are for molds, under-hood prototypes, or parts that see sustained heat. They cost more and are more brittle; use them only when temperature is the deciding factor.
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