High Impact
Resin
The Complete Guide
Standard resin is brittle. High impact resin is built to take a beating. Here's everything you need to know about what makes it different — and how to cure it correctly so your parts perform the way they should.
tough/durable resins
standard resin
for high impact resin
high impact resins
- What Is High Impact Resin?
- The Chemistry That Makes It Tough
- Standard vs. High Impact Resin: Side-by-Side
- Types of Impact-Resistant Resins
- When Should You Use It?
- Printing Settings for High Impact Resin
- Curing: Where Everything Changes
- Step-by-Step Post-Cure Process
- Common Mistakes and How to Avoid Them
- The Blending Trick: Mixing Tough + Standard
- Recommended Brands and Products
- FAQ
If you've been resin printing for more than a few weeks, you've probably experienced it: a print comes out looking perfect, you remove the supports, and then — snap. A thin section breaks clean off. Or a client picks up a prototype, flexes it slightly to test it, and it shatters like glass.
That's the defining limitation of standard photopolymer resin. It's rigid. It's precise. It's beautiful. And it's brittle.
High impact resin is the answer to that problem. It's a category of specialized photopolymer materials engineered with different molecular architectures that allow them to absorb and distribute mechanical energy rather than concentrating it at a fracture point. They don't just feel different in your hands — they perform fundamentally differently in the real world.
In this guide, we'll break down exactly what makes high impact resin different from the standard stuff, which applications actually need it, and — critically — how to cure it properly, because the post-cure process for high impact formulations is noticeably different from what you'd do with standard resin. Get it wrong and you'll undo the material's advantages before your part ever sees service.
What Is High Impact Resin?
High impact resin is a broad category of photopolymer resin designed to resist fracture and deformation when subjected to sudden mechanical forces — drops, vibrations, compression loads, or flex stresses that would cause standard resin to crack or shatter.
You'll see it marketed under several names depending on the manufacturer and formulation: tough resin, ABS-like resin, durable resin, engineering resin, tenacious resin, or simply "impact resistant." While these aren't all identical — there are meaningful differences between them, which we'll cover — they all share the goal of surviving real-world mechanical stress better than standard photopolymers.
The simplest way to understand high impact resin is to contrast it with what standard resin does under stress. Standard resin is a rigid, highly crosslinked polymer network. When a force is applied to it, that stress concentrates at microscopic weak points (surface scratches, layer boundaries, voids) and initiates crack propagation. The crack runs fast through the rigid structure and the part fails suddenly.
High impact resin introduces flexible molecular segments into that same polymer network. When stress is applied, the flexible segments can absorb and dissipate energy by deforming elastically — essentially acting as microscopic shock absorbers — before any crack propagation can begin. The result is a part that may deform slightly under load but doesn't simply break.
"The difference isn't just in how hard the part is — it's in how the part responds when that hardness is exceeded."
The Chemistry That Makes It Tough
Standard resins are built primarily from rigid acrylate or methacrylate monomers and oligomers. When UV light hits these, they crosslink rapidly into a dense, stiff polymer network with very high compressive and flexural strength — but minimal elongation at break, typically 1–3%. The part is strong until it isn't, and then it fails catastrophically.
High impact formulations change this in several ways:
1. Aliphatic Urethane Acrylate Oligomers
Many tough resins use aliphatic urethane acrylate oligomers as their backbone instead of pure epoxy acrylates. Urethane linkages are inherently more flexible than epoxy linkages, giving the cured polymer chains more freedom to flex before breaking. This is the same chemistry behind polyurethane coatings used on industrial floors and automotive clear coats — materials famous for taking repeated abuse.
2. Rubber-Phase Toughening
Some high impact formulations incorporate rubbery microparticles or block copolymers that create a two-phase microstructure in the cured part. When a crack tries to propagate, it encounters these rubber domains, which deform and absorb the crack-tip energy, effectively arresting crack growth. This is the same mechanism used in high-impact polystyrene (HIPS) and ABS plastics — which is exactly why the results feel "ABS-like."
3. Controlled Crosslink Density
The toughness-brittleness balance in photopolymers is directly related to crosslink density. Denser crosslinking = harder and stiffer but more brittle. Lower crosslink density = more flexible and tough but softer. High impact resins are engineered to hit an optimal crosslink density that preserves functional hardness while dramatically improving the material's ability to absorb impact energy. This is also why curing parameters matter so much — over-curing pushes the crosslink density too high, moving the material back toward brittle behavior.
Standard vs. High Impact Resin: Side-by-Side
Here's a clear-eyed look at how these two material categories compare across the properties that matter most for functional printing:
| Property | Standard Resin | High Impact / Tough Resin |
|---|---|---|
| Impact Strength (Notched Izod) | 13–16 J/m | 41–68 J/m |
| Tensile Strength | 40–55 MPa | 40–70 MPa |
| Elongation at Break | 1–3% | 10–35% |
| Flexural Modulus | 2.0–3.0 GPa (very stiff) | 1.2–2.2 GPa (moderately stiff) |
| Surface Detail Resolution | Excellent | Good |
| Drop/Shock Resistance | Poor | Excellent |
| Print Speed / Ease | Fast, forgiving | Moderate — needs care |
| Post-Cure Time | 5–15 minutes | 30–60 minutes |
| Cure Temperature Needed | Room temp fine | ~60°C recommended |
| Over-Cure Risk | Low (just gets slightly harder) | High (can become brittle) |
| Best For | Miniatures, art models, dental, display | Functional parts, snap-fits, enclosures, tools |
| Price Per Liter | $20–$35 | $35–$65 |
High impact resin's edge isn't raw tensile strength — standard resin actually isn't far behind there. The real difference is in impact energy absorption (4× better) and elongation at break (10× better). Those two properties are what define whether a part survives real-world use.
Types of Impact-Resistant Resins
Not all "tough" resins are the same. Here's how the main subcategories break down:
ABS-Like Resin
Mimics the stiffness and toughness balance of ABS plastic. Good for enclosures, brackets, and parts needing dimensional stability with impact resistance. The most popular category for functional printing.
Tough / Durable Resin
Higher elongation at break than ABS-like. Designed to flex significantly before breaking. Best for snap-fits, living hinges, and parts that need to bend repeatedly without fatiguing.
Flexible / Tenacious Resin
Very high elongation (some formulations 180° bend without breaking). Partially rubberized character. Often mixed with standard resin in ratios of 10–30% to impart toughness without going fully flexible.
Engineering / High-Performance Resin
Premium formulations that combine high impact strength with elevated temperature resistance (HDT 70–150°C+). Target industrial and professional applications. Significantly more expensive and demanding to print.
When Should You Use High Impact Resin?
High impact resin costs more, takes longer to cure, and requires more careful dialing-in than standard resin. That means it's not automatically the right choice — you should use it when the application actually demands it.
Use High Impact Resin For:
- Functional prototypes and end-use parts — components that will be handled, installed, or subjected to any mechanical stress in service
- Snap-fits and living hinges — standard resin will crack the first time these are flexed; tough resin is specifically designed for repeated flex cycles
- Enclosures and housings — electronics housings, tool handles, fixture bodies — anything that might be dropped
- Clip, bracket, and fastener applications — parts that need to hold or flex under load without fracturing
- Wearable and ergonomic parts — handles, grips, straps, or anything in contact with users who will apply unexpected forces
- Props and cosplay pieces — intricate display pieces that will be handled frequently need shock resistance even if they don't carry load
- Sports accessories — our carbon fiber golf tees and other sports-adjacent prints benefit from impact-tolerant resin on high-detail functional pieces
Stick with Standard Resin For:
- Tabletop miniatures and display models that won't be handled roughly
- Dental models, jewelry casting masters, and other precision display applications
- Decorative objects placed on shelves or in protected environments
- Patterns and bucks that need maximum surface detail reproduction
High impact resin usually has slightly lower surface detail resolution than premium standard resins due to its different viscosity and curing characteristics. For ultra-fine miniature detail (under 0.1mm feature size), standard resin still wins. Choose based on what the part actually needs to do.
Printing Settings for High Impact Resin
High impact resins have different optical and physical properties than standard formulations, which means your slicer settings need adjustment. Don't just pour it into the vat and run your existing profile — you'll likely get adhesion issues, layer separation, or failed supports.
Key Setting Differences
Exposure Time: Most ABS-like and tough resins require slightly longer layer exposure times than standard resin — typically 10–25% more. The flexible oligomers cure more slowly than rigid acrylates at the same UV dose. Start at the manufacturer's recommended time and bracket up/down with a test print.
Bottom Layer Exposure: High impact resins often need 6–10 bottom layers (vs. 3–5 for standard) with longer bottom exposure times to ensure a solid bond to the FEP and build plate. Because these resins tend to be more flexible when partially cured, inadequate bottom layers leads to layer separation during the first few layers.
Lift Speed and Distance: The more flexible nature of partially-cured high impact resin makes it more prone to deformation during the peel force (when the layer separates from the FEP). Reduce your lift speed by 20–30% compared to standard resin settings. Some makers also reduce their TSMC/lift distance slightly to minimize stress on early layers.
Temperature: If your printer supports a heated vat (like the Elegoo Saturn 4 Ultra's heat function), warming the resin to 30–35°C significantly improves viscosity and layer-to-layer adhesion for tough and ABS-like formulations. Cold resin is notably more prone to layer delamination with these materials.
Supports: High impact resin is slightly more flexible during printing, which can cause fine supports to bend rather than hold position. Use denser support structures or increase support tip size slightly compared to your standard resin settings.
Curing: Where Everything Changes
Post-curing high impact resin is genuinely different from curing standard resin, and it's where most people go wrong. Get this step right and you'll have parts that are dramatically more durable than anything standard resin can produce. Get it wrong and you'll either have under-cured parts with poor strength, or over-cured parts that have lost their toughness advantage and become brittle again.
Here's the core reason the process differs: high impact resins rely on their specific crosslink density to achieve their mechanical properties. That density is the result of a precise UV dose. Standard resin is fairly forgiving — a bit more UV mostly just makes it harder. High impact resin has a Goldilocks window. Too little UV and the flexible segments aren't fully polymerized. Too much UV and you're aggressively crosslinking those flexible segments, destroying the toughness you paid for.
Additionally, heat plays a much larger role in post-curing high impact resin than standard resin. Using simultaneous heat and UV during post-cure dramatically increases the degree of polymer conversion — meaning more of the potential crosslinks actually form. Research from CNC Kitchen demonstrated that dual heat+UV post-curing produces significantly better mechanical properties than UV alone for tough and ABS-like resin families. Standard resins see some benefit too, but the effect is much more dramatic for tough formulations.
"Heat and UV together, not just UV alone — that's the combination that unlocks what high impact resin is actually capable of."
Why Standard Cure Times Don't Apply
Standard resins cure in 5–15 minutes at ~60°C in most consumer UV stations. Makers often apply these same times to tough resins and wonder why the parts still feel slightly rubbery or don't perform to the material's published specs. The reason is that the flexible oligomers in tough formulations simply require a higher UV dose to fully convert. The standard cure window isn't long enough.
The comparison below shows the difference in post-cure approach:
Post-Cure Protocol
- UV station or sunlight
- 5–15 minutes total
- Room temp acceptable
- 60°C recommended but not critical
- Rotation helpful but not essential
- Over-cure rarely a problem
Post-Cure Protocol
- UV station with heat required
- 30–60 min (small–medium parts)
- 60°C with UV simultaneously
- Rotation is essential
- Cool slowly after cure
- Over-cure causes brittleness
Step-by-Step: How to Properly Cure High Impact Resin
Follow this process carefully for every high impact resin print. Cutting corners on any step — especially washing and cure time management — directly degrades the final mechanical properties.
Remove from Build Plate While Wet
Leave supports on during removal to protect the part. Handle with nitrile gloves — uncured high impact resin contains the same isocyanate and acrylate compounds as standard resin and is a skin irritant. Don't let the part flex unnecessarily at this stage; wet high impact resin is even more deformable than wet standard resin.
First Wash: Remove Surface Resin
Use IPA (91% or higher) or a dedicated resin wash solution. Agitate for 3–5 minutes. For ABS-like resins, some makers prefer TPM (tripropylene glycol monomethyl ether) over IPA because TPM is gentler on partially-cured flexible polymers and reduces brittleness risk from excessive IPA exposure. Either works, but avoid over-washing — IPA absorption into thick, flexible parts can slightly affect final properties.
Second Wash (For Complex Geometry)
For parts with deep channels, hollow sections, or internal geometry, do a second wash in fresh IPA for 1–2 minutes to clear any trapped uncured resin. Uncured resin left inside a part will create soft spots that no amount of post-curing will fix. For solid or simple parts, one wash is usually sufficient.
Dry Completely Before Curing
This step is more critical for high impact resin than standard. Residual IPA on the surface when you put the part under UV will inhibit surface curing and can cause cloudiness or surface tackiness that's very difficult to fix. Air dry for 10–15 minutes minimum, or use a fan. The surface should feel dry to the touch (gloved) with no solvent odor before proceeding.
Remove Supports After Washing, Before Curing
For high impact resin, remove supports after washing but before UV post-curing. This is different from standard resin workflow where you might remove supports either way. High impact resin, once fully post-cured, is significantly tougher and support removal becomes more difficult and can stress the part. When supports are removed in the partially-cured state post-wash, the material is still somewhat compliant and support scars are easier to clean up.
Load into a UV Curing Station with Heat
Place the part in your UV cure station — an Elegoo Mercury, Anycubic Wash & Cure, Formlabs Form Cure, or equivalent. Preheat the station to 60°C before inserting the part. Ensure the part is on the rotating turntable. If your station has a water-immersion option for curing, skip it for high impact resins — water immersion is great for standard clear resins but can slightly affect surface properties of tough formulations.
Cure Time: 30–60 Minutes at 60°C
Set your cure station for 30 minutes as a baseline for small/medium parts (under 100mm in any dimension). Increase to 45–60 minutes for larger, thicker, or hollow parts. The critical rule: heat and UV must run simultaneously — not sequentially. Pure heat without UV doesn't cure it; pure UV without heat under-cures the flexible segments. The combination is what produces optimal mechanical properties. If your station doesn't have temperature control, cure for 45–60 minutes at room temperature and accept slightly reduced properties.
Flip and Re-Cure If Needed
For parts with significant self-shading — complex overhangs, recessed features, internal channels — after the first cure cycle, flip or reposition the part and run an additional 15–20 minute cycle. The rotation helps a lot, but geometry that shadows itself may still have under-cured zones. A tap test (the part should produce a clear, resonant "clink" rather than a dull thud) is a good indicator of proper cure — though this is less diagnostic for flexible formulations than for rigid ones.
Cool Slowly — Do Not Quench
After the UV cycle completes, leave the part in the cure station with the UV off but the heat on for 5–10 minutes, then remove and allow to cool at room temperature. Do not immediately drop the hot part into cold water or blast it with compressed air to cool it quickly. Thermal shock during cooling can cause micro-cracking in partially-crosslinked high impact resins, especially in thin sections. Let it cool naturally.
Test and Validate
The first time you use a new high impact resin formulation, print a test coupon — a simple 80×10×4mm bar — alongside your real part and do a manual flex test after curing. A properly cured high impact resin bar should flex noticeably (several millimeters of deflection) before showing any signs of stress whitening. If it snaps cleanly with minimal deflection, you're likely under-cured or using print settings that are causing layer delamination.
Common Mistakes and How to Avoid Them
Mistake 1: Using Standard Resin Cure Times
This is the single most common error. 10 minutes at 60°C is usually right for standard resin and dangerously under-cured for tough resin. The flexible segments need more UV dose to fully polymerize. Result: parts that feel slightly rubbery, have reduced hardness, and will deform in warm environments.
Mistake 2: Curing Without Heat
UV without heat won't unlock the full mechanical potential of high impact resin. The heat drives thermal polymerization of segments that UV alone can't reach, particularly in thicker cross-sections. If you're using a DIY UV cure box or UV nail lamp without a heat source, you're leaving a significant portion of the material's performance on the table.
Mistake 3: Over-Curing for "Extra Strength"
More cure time doesn't mean stronger parts for high impact resin. After the optimal UV dose, continued exposure crosslinks the very flexible segments that give the material its toughness. The result is progressively more brittle behavior — the exact opposite of what you want. Always follow the recommended cure window for your specific resin.
Running high impact resin for 2 hours in a cure station because "more is more" is a common mistake. The parts will look fine — but snap test them and they'll be nearly as brittle as standard resin. Over-curing destroys toughness. Trust the manufacturer's cure time recommendation.
Mistake 4: Washing With Contaminated IPA
Heavily resin-contaminated wash solvent leaves a thin film of uncured resin on the part's surface. When you then put it in the cure station, this film cures but isn't strongly bonded — resulting in a tacky, peeling surface coating. Use fresh IPA for the second wash stage, or use a two-stage wash system.
Mistake 5: Printing With Cold Resin
High impact resins are notably more viscous when cold and don't flow as readily into fine features. Printing at room temperature in a cold garage in winter is a recipe for layer separation and print failures. Bring your resin to at least 20–25°C before printing, or use a heated vat if available.
The Blending Trick: Mixing Tough + Standard Resin
One of the most useful techniques in the advanced resin maker's toolkit is blending high impact resin into standard resin to achieve a customized balance of toughness and surface detail that neither material alone provides.
The principle is straightforward: add 10–30% of a flexible or tenacious resin to your standard resin by volume. Shake thoroughly. The resulting blend will cure at approximately the midpoint of the two materials' cure times and will exhibit measurably improved toughness (better elongation and impact resistance) while retaining most of the surface quality of the standard resin.
Recommended Blend Ratios
- 10% tough / 90% standard: Improved toughness for miniatures and detailed parts where detail is still the priority. Minimal visible change in surface quality.
- 20% tough / 80% standard: A good all-purpose blend for functional prints that need both detail and durability. This is the most popular ratio in the maker community.
- 30% tough / 70% standard: Noticeably tougher — appropriate for parts that will see real mechanical stress. Slight reduction in fine surface detail resolution.
- 50/50: Approaches the properties of the tough resin alone. Use when you need flexibility and don't mind the loss of fine detail.
When blending for the Saturn 4 Ultra's 16K screen, start with the standard resin's exposure profile and add 10–15% additional exposure time per layer when using a 20%+ tough blend. The flexible resins in the mix reduce photon absorption efficiency slightly. Always run a calibration print with any new blend ratio before committing to a production run.
Recommended High Impact Resin Brands and Products
The market for tough and high impact resins has matured significantly. Here are the formulations that have the strongest track records among hobbyist and professional users:
Siraya Tech Tenacious
The gold standard for blending applications. Siraya Tech Tenacious is a highly flexible resin specifically designed to be mixed with standard resins at 10–30% ratios. In pure form, it achieves extreme flexibility — thin prints can be bent 180° without breaking. It's compatible with virtually all LCD/MSLA printers including the full Elegoo, Anycubic, Phrozen, and Creality lineups. This is one of the most widely recommended flexible additives in the resin printing community and for good reason — it's consistent, well-documented, and ships with clear TDS data.
Siraya Tech Fast Tough (ABS-Like)
Designed to be used straight without blending. Fast Tough delivers good toughness and impact resistance in an easy-printing, low-odor formulation compatible with 4K through 16K LCD printers. It occupies the balanced middle ground between standard rigidity and full flexible toughness — print settings are similar to standard resin, making it the easiest transition for makers moving from standard to functional printing.
Elegoo ABS-Like Resin Pro
Elegoo's own ABS-like formulation designed specifically for their printer lineup (Saturn, Jupiter, Mars series). Tuned to work well with Elegoo's default slicer profiles, it's a practical choice if you're already printing on an Elegoo machine and want minimal settings adjustment. Good toughness and color consistency across batches.
Phrozen Tough 4K / 8K Resin
Phrozen's tough series is well-regarded in the professional prototyping community for its consistent mechanical properties and reliable print results. Higher price point but strong batch-to-batch consistency — important for production applications where you need predictable part performance.
Formlabs Tough 2000
If you're running an SLA machine in a professional context, Formlabs' engineering-grade resins represent the top of the market for tested, certified mechanical properties. Tough 2000 simulates ABS with exceptional consistency. The Form Cure station with pre-programmed settings for each resin removes the guesswork from post-curing entirely. Premium pricing reflects the professional support ecosystem.
Wrapping Up: Use the Right Material for the Right Job
High impact resin isn't just "better" resin — it's a different tool with a different purpose. Standard resin excels at what it's designed for: fine detail, surface quality, and dimensional precision for display and master pattern applications. High impact resin is designed to survive the real world — functional hardware, snap-fit assemblies, wearable accessories, and anything that will be dropped, flexed, or stressed in service.
The curing step is where the difference really lives. Standard resin is forgiving — cure it a bit long or a bit short and you'll get a good result. High impact resin demands precision. Give it simultaneous heat and UV, respect the cure time window, and let it cool slowly. Do that and you'll have parts that outperform ABS in certain impact scenarios — a genuinely remarkable result from a material that also prints at better-than-injection-molded surface quality.
At Dreaming3D in San Diego, we work with the full range of resin formulations — standard, ABS-like, tough, flexible, and high-temp — across our Elegoo Saturn 4 Ultra 16K and other production machines. Whether you need a custom functional part, want help dialing in settings for a tough resin you've been struggling with, or need a prototype that has to survive actual testing, we're here to help.
Reach us at 858-342-6984 or dreaming3dprinting@gmail.com, or visit dreaming3d.net to submit a project request.
Frequently Asked Questions
High impact resin is a specialized photopolymer formulated with flexible oligomers and rubber-toughening additives that allow it to absorb mechanical shock without shattering. Unlike standard resin which is rigid and brittle, high impact resin can flex slightly under load and resist cracking, making it ideal for functional parts that will experience real-world stress.
Standard resin offers excellent detail and surface finish but is brittle — it will snap rather than flex under impact. High impact resin trades some rigidity for significantly better impact strength (often 41–68 J/m vs. 13–16 J/m for standard) and elongation at break (up to 35% vs. 1–3% for standard), meaning it can flex and absorb energy before it breaks rather than fracturing suddenly.
High impact and tough/durable resin families typically require 30–60 minutes in a UV curing station at around 60°C for optimal mechanical properties, compared to 5–15 minutes for standard resins. Thicker sections or complex geometries may need up to 90 minutes. Always rotate the part during curing to ensure even UV exposure on all faces.
Yes — and this is actually a bigger concern than with standard resin. Prolonged UV exposure at elevated temperatures can cause embrittlement — the very property you're trying to avoid. Continuous over-curing crosslinks the flexible molecular segments that give the resin its toughness, turning it progressively more brittle. Always follow the manufacturer's recommended cure time and don't add extra time "just to be sure."
Yes — this is actually one of the most popular techniques among experienced makers. Mixing a flexible or tenacious resin (like Siraya Tech Tenacious) at 10–30% into standard resin significantly boosts toughness while retaining most of the detail and surface quality of the standard resin. A 20% tough / 80% standard blend is the most commonly recommended starting ratio.
Most high impact resins cure at 405nm, the same wavelength as standard LCD/MSLA resins, so they're compatible with the same printers and post-cure stations you already own. Some engineering-grade tough resins specify 385nm or dual-wavelength stations — always check your resin's Technical Data Sheet (TDS) before purchasing.
Yes! Dreaming3D operates out of San Diego, CA and offers both FDM and resin 3D printing services on professional-grade equipment including the Elegoo Saturn 4 Ultra 16K. We can print in standard, ABS-like, tough, and specialty resins depending on your project's mechanical requirements. Contact us at 858-342-6984 or visit dreaming3d.net to discuss your project.
Need a Tough Part Printed Right?
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Dreaming3D · San Diego, CA · 858-342-6984 · dreaming3dprinting@gmail.com · dreaming3d.net