DFM for 3D Printing: A Practical Design Guide
Wall thickness, tolerances, supports, and hole sizing rules for printable parts.
Read the ArticleGrey V5 3D Printing Material
Stereolithography (SLA) · General Purpose Resins
Strong, stiff general-purpose resin with a smooth matte finish - the SLA workhorse.
What Is Grey V5?
Grey V5 is the baseline Formlabs SLA resin - strong, stiff, and dimensionally accurate with a clean matte-grey finish. It delivers 62 MPa tensile and 2,750 MPa flex modulus at 25–100 µm resolution, making it a reliable first choice for functional prototypes, fit checks, and appearance models on the Form 4 platform.
Formlabs Grey Resin V5, printed with Stereolithography (SLA). Every order is reviewed by our engineering team - no minimum order quantity.
When to choose Grey V5
Choose Grey V5 when you need a strong, precise SLA part and do not require transparency, extreme heat resistance, or high elongation. At 62 MPa tensile and 2,750 MPa flex modulus, Grey V5 outperforms Accura 25 on strength while running on the Form 4 at a lower cost tier. It is the default starting point for SLA prototyping in our Formlabs catalog.
If you need to see through the part, switch to Clear V5 - it offers similar mechanical properties with near-optical transparency when polished. If your part must survive repeated flexing or impact, the Tough series is the correct choice: Tough 2000 for ABS-like toughness, Tough 1500 for PP-like snap-fits, or Tough 1000 for HDPE-like elongation.
Grey V5's 71 °C HDT is adequate for most room-temperature functional prototyping but not for thermal environments. For heat above 100 °C, Rigid 10K (238 °C HDT) is the Formlabs answer. For general-purpose prototyping where cost and turnaround matter most, Grey V5 is the workhorse.
Material Properties
Representative values - process- and orientation-dependent. Full technical datasheet available on request.
Process
Stereolithography (SLA)
Tensile strength
62 MPa
Elongation at break
13%
Flexural strength
103 MPa
Flexural modulus
2,750 MPa
Heat deflection (HDT)
71 °C @ 0.45 MPa
Density
1.18 g/cm³
Max build size
200 × 125 × 210 mm (Form 4)
Min wall thickness
0.3 mm
Resolution / layer
25–100 µm
Relative cost
$$ (1 = lowest, 4 = highest)
Design Guidelines
Plan features to print reliably and assemble cleanly in Grey V5. Need DFM help?
Min wall
0.3 mm - 0.5 mm+ for handling strength
Min feature
0.2 mm - at 25 µm layer height
Clearance
0.2–0.3 mm - for mating parts
Max size
200 × 125 × 210 mm - Form 4 build volume
Dimensional tolerances
Typical tolerance on the Form 4 is ±0.1 mm or ±0.1% on well-oriented parts. Features in the XY plane are most accurate; tall Z-axis features may accumulate slight drift. Support contact points add 0.2–0.4 mm witness marks that are easily sanded. Post-machining is available for critical bores and mating surfaces but is rarely necessary at this resolution.
Printing notes
Grey V5 prints on the Form 4 at 25–100 µm layer height depending on detail requirements. After printing, parts are washed in IPA (isopropyl alcohol) for 10–15 minutes to remove uncured resin, then post-cured at 60 °C for 30 minutes under 405 nm UV light to reach full mechanical properties. Supports are auto-generated and leave small contact points (0.2–0.4 mm) that sand away cleanly. The matte-grey pigment hides minor surface imperfections better than clear or translucent resins. Orientation is optimized to minimize support contact on cosmetic faces.
How Grey V5 Compares
Grey V5 alongside related materials.
| Grey V5 | Clear V5 | Tough 2000 | Grey V5 | |
|---|---|---|---|---|
| Tensile strength | 62 MPa | 60 MPa | 42 MPa | 62 MPa |
| Heat deflection (HDT) | 71 °C @ 0.45 MPa | 74 °C @ 0.45 MPa | 54 °C @ 0.45 MPa | 71 °C @ 0.45 MPa |
| Flexural modulus | 2,750 MPa | 2,750 MPa | 1,500 MPa | 2,750 MPa |
| Elongation | 13% | 8% | 79% | 13% |
| Density | 1.18 g/cm³ | 1.18 g/cm³ | 1.15 g/cm³ | 1.18 g/cm³ |
| Relative cost | $$ | $$ | $$$ | $$ |
When to Use Grey V5
Where Grey V5 fits, where it doesn't, and what to use instead.
Functional fit-check prototypes
62 MPa tensile and ±0.1 mm tolerance let engineers validate snap-fits, clearances, and interference fits before committing to injection-mold tooling.
EngineeringCosmetic appearance models
Matte-grey finish at 25 µm layer height produces parts that pass stakeholder review without sanding or painting in most cases.
Consumer ProductsEnclosure and housing prototypes
103 MPa flexural strength resists flex during assembly and handling, making printed housings functional enough for drop-in electronics integration.
Consumer ProductsArchitectural concept models
0.3 mm minimum wall and 25 µm resolution capture mullions, fenestration patterns, and facade textures at 1:50 scale that FDM cannot reproduce.
ArchitecturePre-production verification parts
Consistent batch-to-batch properties on Form 4 let QE teams validate geometry against GD&T callouts before releasing tooling for injection molding.
EngineeringStrengths
- 62 MPa tensile - strongest general-purpose SLA resin in the catalog, outperforming Accura 25 (45–47 MPa) by 30%
- 25–100 µm resolution with smooth matte-grey finish straight off the printer - minimal post-processing for appearance-grade parts
- Lowest-cost Formlabs resin at $$ tier - the economical default for SLA prototyping on the Form 4 platform
Keep in mind
- 71 °C HDT is better than Accura 25 (51 °C) but still modest - parts will soften near electronics heat sinks or in direct sun; use Rigid 10K for thermal applications
- 13% elongation is adequate for snap-fit validation but parts will crack under repeated impact; switch to Tough 2000 (79% elongation) for durability
- 200 × 125 × 210 mm build volume is smaller than industrial SLA (380 mm³) or SLS (550 mm tall) - oversized parts must be split or moved to a larger-format process
Finishes & Colors
Finishing options and in-stock colors for Grey V5.
Standard
Washed, post-cured, supports removed; smooth matte-grey surface.
Best for: Functional prototypes, fit checks
Sanded + Primed
Support marks removed, primed for painting.
Best for: Appearance models, paint-ready parts
In-Stock Colors
Grey
Custom colors and dyeing available on request. Contact us for options.
Grey V5 FAQ
Grey V5 is the general-purpose Formlabs SLA resin for functional prototypes, fit checks, and appearance models. It combines 62 MPa tensile strength with 25 µm resolution and a smooth matte finish, making it the default starting point for most SLA jobs on the Form 4.
Grey V5 is significantly stronger - 62 MPa tensile vs 33 MPa for FDM ABS - and far more precise at ±0.1 mm vs ±0.3 mm. However, ABS is tougher under impact and has higher heat resistance (87 °C vs 71 °C HDT). Choose Grey V5 for precision and surface quality; ABS for toughness and heat.
Grey V5 has a 71 °C HDT at 0.45 MPa - better than Accura 25 (51 °C) but not suitable for hot environments. For heat above 100 °C, use Rigid 10K (238 °C HDT). For moderate heat with toughness, consider FDM ABS or PC-FR.
Grey V5 is stronger (62 MPa vs 45 MPa), runs on the Form 4 at lower cost ($$ vs $$$$), and has better heat resistance (71 °C vs 51 °C HDT). Accura 25 offers a larger build volume (380 mm³ vs 200 mm) on industrial SLA. Choose Grey V5 for most prototyping; Accura 25 for oversized parts.
Grey V5 produces a smooth matte-grey surface with minimal visible layer lines at 25–50 µm. The neutral grey color hides minor surface imperfections and provides a professional look without post-processing. Sanding and priming are available for paint-ready finishes.
The Form 4 holds ±0.1 mm or ±0.1% on Grey V5 parts. This is 3x tighter than FDM and matches industrial SLA precision. Support witness marks are 0.2–0.4 mm and sand away easily. Specify cosmetic faces so we orient supports away from them.
At the $$ tier, Grey V5 is the most affordable Formlabs resin. The Form 4 build volume (200 × 125 × 210 mm) can nest multiple small parts per build, reducing per-part cost. For 50+ identical parts, MJF PA12 may be more cost-effective with better mechanical properties.
Grey V5 accepts primer and paint well after light sanding. The matte-grey base provides a neutral starting point for any paint color. We offer sanded-and-primed finishing to prepare parts for custom painting. Dyeing is not standard for SLA resins - painting is the preferred coloring method.
Technical Documents
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