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 ArticleTough 1000 3D Printing Material
Stereolithography (SLA) · Engineering Resins
HDPE-like resin with 180% elongation and exceptional fatigue resistance.
What Is Tough 1000?
Tough 1000 is the most flexible resin in the Formlabs engineering lineup, delivering 180% elongation and 26.3 MPa tensile with a feel similar to HDPE. It excels at parts that must bend repeatedly, absorb impact, or deform without fracturing - squeeze-to-open mechanisms, flexible snap-tabs, and fatigue-loaded fixtures.
Formlabs Tough 1000 Resin, printed with Stereolithography (SLA). Every order is reviewed by our engineering team - no minimum order quantity.
When to choose Tough 1000
Choose Tough 1000 when your SLA part must bend, flex, or deform repeatedly without fracturing. At 180% elongation, it simulates HDPE behavior - the kind of deformation you see in squeeze bottles, flexible packaging caps, and cable clips. No other SLA resin in the catalog comes close to this level of flexibility.
Tough 1000 is not strong or stiff - 26.3 MPa tensile and 932 MPa flex modulus put it well below Grey V5 and the other Tough resins. The trade-off is intentional: you choose Tough 1000 specifically because you need a part that gives rather than cracks. If you need more stiffness with still-good elongation, move up to Tough 1500 (PP-like, 33 MPa, 30–40%) or Tough 2000 (ABS-like, 42 MPa, 79%).
For true elastomeric behavior - rubber-like compression and rebound - FDM TPU is a different category entirely. Tough 1000 is a flexible plastic, not an elastomer. Its advantage over TPU is SLA precision: ±0.1 mm tolerances and fine features that FDM TPU cannot achieve.
Material Properties
Representative values - process- and orientation-dependent. Full technical datasheet available on request.
Process
Stereolithography (SLA)
Tensile strength
26.3 MPa
Elongation at break
180%
Flexural modulus
932 MPa
Heat deflection (HDT)
55 °C @ 0.45 MPa
Density
1.15 g/cm³
Max build size
200 × 125 × 210 mm (Form 4)
Min wall thickness
0.5 mm
Resolution / layer
50–100 µm
Relative cost
$$$ (1 = lowest, 4 = highest)
Design Guidelines
Plan features to print reliably and assemble cleanly in Tough 1000. Need DFM help?
Min wall
0.5 mm - thin walls flex more
Min feature
0.3 mm - at 50 µm layer height
Clearance
0.3–0.4 mm - for snap-fit assemblies
Max size
200 × 125 × 210 mm - Form 4 build volume
Dimensional tolerances
Typical tolerance on the Form 4 is ±0.1 mm or ±0.15%. Flexible materials may spring back after printing, so very thin features can shift slightly from nominal geometry. Parts thicker than 3 mm hold tolerance well. Post-machining is not recommended on Tough 1000 - the material deforms under tooling pressure.
Printing notes
Tough 1000 prints on the Form 4 at 50–100 µm layer height. After printing, wash in IPA for 15–20 minutes - slightly longer than rigid resins because the flexible surface retains resin in concavities. Post-cure at 60 °C for 60 minutes under 405 nm UV light. Under-curing leaves parts too soft; over-curing makes them stiffer and more brittle than spec. Support removal requires care - the flexible material can tear at thin support contact points. Orient parts to minimize supports on thin-wall regions.
How Tough 1000 Compares
Tough 1000 alongside related materials.
| Tough 1000 | Tough 1500 | Tough 2000 | Durable | |
|---|---|---|---|---|
| Tensile strength | 26.3 MPa | 33 MPa | 42 MPa | 28 MPa |
| Heat deflection (HDT) | 55 °C @ 0.45 MPa | 52 °C @ 0.45 MPa | 54 °C @ 0.45 MPa | 41 °C @ 0.45 MPa |
| Flexural modulus | 932 MPa | 1,400 MPa | 1,500 MPa | - |
| Elongation | 180% | 30–40% | 79% | 55% |
| Density | 1.15 g/cm³ | 1.15 g/cm³ | 1.15 g/cm³ | 1.13 g/cm³ |
| Relative cost | $$$ | $$$ | $$$ | $$$ |
When to Use Tough 1000
Where Tough 1000 fits, where it doesn't, and what to use instead.
Squeeze-fit and deformable packaging prototypes
180% elongation lets printed prototypes replicate the squeeze-to-open and living-hinge behavior of HDPE bottles and caps for consumer testing.
Consumer ProductsFatigue-loaded clips and cable management
Exceptional fatigue resistance survives thousands of flex cycles on cable clips, retaining tabs, and snap-on covers that must open and close daily.
EngineeringFlexible medical device components
HDPE-like compliance at 932 MPa flex modulus lets designers validate catheter hubs, flexible connectors, and luer fittings in a printed prototype rather than waiting for molded samples.
Medical DevicesImpact-absorbing bumpers and guards
High elongation absorbs and distributes impact energy across the part surface rather than fracturing - suitable for protective guards on robotics and automation equipment.
RoboticsFlexible functional test fixtures
Printed fixtures that must flex around irregular workpieces during inspection or assembly without cracking on the 50th cycle.
EngineeringStrengths
- 180% elongation - highest of any SLA resin in the catalog - replicates HDPE-like deformation for squeeze-fit and living-hinge validation
- Exceptional fatigue resistance across thousands of flex cycles - printed clips and hinges hold up where rigid SLA resins crack after a handful of bends
- SLA precision (±0.1 mm, 50 µm layers) on flexible geometry that FDM TPU cannot hold - fine-feature flexible prototypes with real dimensional accuracy
Keep in mind
- 26.3 MPa tensile and 932 MPa flex modulus - substantially weaker and softer than Grey V5 (62 MPa, 2,750 MPa); not for load-bearing structural applications
- 55 °C HDT is among the lowest in the catalog - parts soften in warm environments; combine with heat exposure is not viable
- Translucent-green color only - if a specific color or opacity is needed, parts must be painted, which may stiffen thin sections
Finishes & Colors
Finishing options and in-stock colors for Tough 1000.
Standard
Washed, post-cured; translucent green surface.
Best for: Functional flexible prototypes
In-Stock Colors
Translucent Green
Custom colors and dyeing available on request. Contact us for options.
Tough 1000 FAQ
Tough 1000 simulates HDPE behavior - 180% elongation and excellent fatigue resistance. It is used for squeeze-fit prototypes, flexible snap-tabs, cable clips, living hinges, and any part that must bend repeatedly without breaking. It is the most flexible SLA resin in our catalog.
Tough 1000 is the softest and most flexible (HDPE-like, 180% elongation). Tough 1500 balances flexibility and stiffness (PP-like, 30–40% elongation). Tough 2000 is the stiffest with good toughness (ABS-like, 79% elongation). Choose based on how much flex vs rigidity your application needs.
Tough 1000 is a flexible plastic, not an elastomer like TPU. It bends and deforms without breaking but does not compress and rebound like rubber. Its advantage is SLA precision - ±0.1 mm tolerances and fine features that FDM TPU cannot match. For soft-touch grips and gaskets, TPU is still the right choice.
Tough 1000 has exceptional fatigue resistance for an SLA resin. Thin-section hinges and clips survive thousands of flex cycles without cracking. This is its primary advantage over rigid SLA resins like Grey V5 or Accura 25, which crack after a handful of bends.
Tough 1000 is a prototyping material at the $$$ tier. It excels at validating flexible mechanisms, living hinges, and squeeze-fit behavior before committing to HDPE or PP injection-mold tooling. For production flexible parts, injection-molded HDPE or PP is more cost-effective and durable.
The Form 4 holds ±0.1 mm on Tough 1000 parts. Thin flexible features may spring back slightly after printing. Parts thicker than 3 mm hold geometry well. Specify critical dimensions at quoting so we can optimize orientation.
Tough 1000 has a 55 °C HDT - among the lowest in the catalog. It softens in warm environments and is not suitable for any thermal application. For flexible parts that must also handle heat, consider FDM TPU grades.
Tough 1000 prints in translucent green - the standard Formlabs Tough resin color. If a different color is needed, parts can be painted after post-curing, though paint may stiffen very thin sections. The translucent green is functional and professional-looking for most engineering applications.
Technical Documents
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