Rapid Prototyping Guide: Methods, Materials, and Process Selection
A breakdown of FDM, SLA, SLS, MJF, and CNC machining for prototype development: when to use each, how to match process and material to your validation goal.
Read the ArticleDurable 3D Printing Material
Stereolithography (SLA) · Engineering Resins
Pliable, impact-resistant resin with low friction - like printed polyethylene.
What Is Durable?
Durable is a pliable, impact-resistant SLA resin that mimics polyethylene behavior - low friction, high impact absorption, and good fatigue resistance. At 28 MPa tensile and 55% elongation, it fills the niche between rigid SLA resins and the Tough series for parts that must slide, compress, or absorb repeated shock.
Formlabs Durable Resin, printed with Stereolithography (SLA). Every order is reviewed by our engineering team - no minimum order quantity.
When to choose Durable
Choose Durable when your SLA part must slide, articulate, or absorb impact - and the PE-like tactile quality matters for validation. Durable fills a specific niche: it is not the strongest, the stiffest, or the most flexible resin, but it is the only one that behaves like polyethylene. Its low friction, pliable feel, and impact resistance make it the right choice for bushings, ball joints, sliding contacts, and squeeze-fit prototypes.
If you need more strength with toughness, Tough 2000 (42 MPa, 79% elongation) is the better call - it is stiffer and stronger while still being tough. If you need maximum elongation for squeeze-bottle or living-hinge validation, Tough 1000 (180% elongation) goes further. Durable sits between these for parts that specifically need low friction and PE-like feel.
For production PE or PP parts, MJF PP offers real polypropylene properties with better fatigue life and chemical resistance. Durable is a prototyping material for validating PE-like behavior at SLA precision.
Material Properties
Representative values - process- and orientation-dependent. Full technical datasheet available on request.
Process
Stereolithography (SLA)
Tensile strength
28 MPa
Elongation at break
55%
Flexural strength
24 MPa
Heat deflection (HDT)
41 °C @ 0.45 MPa
Density
1.13 g/cm³
Max build size
200 × 125 × 210 mm (Form 4)
Min wall thickness
0.5 mm
Resolution / layer
50–100 µm
Relative cost
$$$ (1 = lowest, 4 = highest)
Design Guidelines
Plan features to print reliably and assemble cleanly in Durable. Need DFM help?
Min wall
0.5 mm - thicker walls feel stiffer
Min feature
0.3 mm - at 50 µm layer height
Clearance
0.3–0.5 mm - for sliding/articulating parts
Max size
200 × 125 × 210 mm - Form 4 build volume
Dimensional tolerances
Typical tolerance on the Form 4 is ±0.15 mm or ±0.2%. Durable is softer than rigid SLA resins, so thin features may deflect during wash and cure steps. Parts thicker than 2 mm hold geometry well. For sliding-contact features, design clearance of 0.3–0.5 mm per side to account for the material's compliance.
Printing notes
Durable prints on the Form 4 at 50–100 µm layer height. Wash in IPA for 15–20 minutes - the pliable surface can retain resin in concavities. Post-cure at 60 °C for 60 minutes under 405 nm UV light. Cure time affects stiffness - under-cured parts are softer than spec; over-cured parts lose some of the PE-like pliability. Support removal requires care - the soft material can deform at contact points. Tweezers and flush cutters work better than twisting or peeling.
How Durable Compares
Durable alongside related materials.
| Durable | Tough 1000 | Tough 1500 | PP | |
|---|---|---|---|---|
| Tensile strength | 28 MPa | 26.3 MPa | 33 MPa | 30 MPa |
| Heat deflection (HDT) | 41 °C @ 0.45 MPa | 55 °C @ 0.45 MPa | 52 °C @ 0.45 MPa | 100 °C @ 0.45 MPa |
| Flexural modulus | - | 932 MPa | 1,400 MPa | 1,300–1,500 MPa |
| Elongation | 55% | 180% | 30–40% | 20–30% |
| Density | 1.13 g/cm³ | 1.15 g/cm³ | 1.15 g/cm³ | 0.90 g/cm³ |
| Relative cost | $$$ | $$$ | $$$ | $$ |
When to Use Durable
Where Durable fits, where it doesn't, and what to use instead.
Low-friction slider prototypes and bushings
PE-like surface friction lets printed sliders, cam followers, and guide rails validate contact behavior and wear patterns before committing to UHMWPE machined components.
EngineeringBall-joint and socket prototypes
55% elongation with low friction lets ball-and-socket assemblies snap together and articulate smoothly - ideal for toy, prosthetic, and consumer-device joint validation.
Consumer ProductsShock-absorbing protective parts
Pliable construction absorbs and distributes impact energy across the surface, surviving repeated 1 m drops that crack rigid SLA resins on first impact.
Consumer ProductsFlexible packaging prototypes
PE-like stiffness and elongation replicate the feel of polyethylene packaging - squeeze tubes, snap lids, and flexible inserts - for consumer testing.
Consumer ProductsWear-surface test coupons
Low-friction surface allows sliding-contact wear testing against metals and plastics at SLA precision, generating wear data before selecting production polymer.
EngineeringStrengths
- Lowest friction of any SLA resin - PE-like surface for sliding contacts, bushings, and ball-joint assemblies
- 55% elongation with genuine impact absorption - survives repeated drops and compression that shatter rigid SLA resins
- Unique translucent-amber appearance with a waxy PE-like feel - no other resin in the catalog replicates this tactile character
Keep in mind
- 41 °C HDT - the lowest in the Formlabs catalog; parts soften in warm rooms and under direct lighting; indoor room-temperature use only
- 28 MPa tensile and low flex modulus - substantially weaker than Grey V5 (62 MPa) or Tough 2000 (42 MPa); not for structural applications
- Translucent amber color only - may not suit all aesthetics; painting adds stiffness and changes the PE-like tactile properties
Finishes & Colors
Finishing options and in-stock colors for Durable.
Standard
Washed, post-cured; translucent amber, waxy surface.
Best for: Functional sliding and impact parts
In-Stock Colors
Translucent Amber
Custom colors and dyeing available on request. Contact us for options.
Durable FAQ
Durable replicates polyethylene behavior - low friction, pliable, impact-absorbing. Use it for bushings, ball joints, slider prototypes, flexible packaging mock-ups, and any part where PE-like tactile properties are the requirement. It is not the strongest or stiffest resin - its value is in feel and function.
Tough 1000 has higher elongation (180% vs 55%) and is more flexible overall. Durable has lower friction and feels more like PE - waxy and pliable. Choose Tough 1000 for maximum bend and stretch. Choose Durable for low-friction sliding and PE-like feel.
Durable is well suited to prototype bushings and slide bearings due to its low-friction PE-like surface. It validates contact behavior, clearance, and wear patterns at SLA precision. For production bushings, consider UHMWPE or Delrin machined components.
Durable absorbs impact through pliable deformation rather than fracturing. It survives repeated 1 m drops that crack rigid SLA resins. For higher impact resistance with more structural integrity, Tough 2000 is stronger while still being tough.
Durable has a 41 °C HDT - the lowest in the Formlabs catalog. It is designed for room-temperature use only. Parts will soften under warm lighting or in direct sun. For heat-resistant flexible parts, consider FDM TPU grades.
The Form 4 holds ±0.15 mm or ±0.2% on Durable parts. The material is softer than rigid resins, so thin features may flex. For sliding-contact surfaces, design 0.3–0.5 mm clearance per side.
Durable can be painted after post-curing, but paint adds stiffness and changes the PE-like surface properties. If the waxy feel is important to your application, leave the part unpainted. The translucent amber appearance is distinctive and professional for engineering prototypes.
Durable is an SLA resin that simulates PE feel at ±0.15 mm tolerance for prototyping. MJF PP is real polypropylene with production-grade fatigue life, chemical resistance, and batch scalability. Use Durable for feel validation on the Form 4. Use MJF PP for end-use PP parts at production volumes.
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