May 18th, 2026

5/18/2026

QTS USA Flexible 405nm Resin Buyer’s Guide

Flexible Resin vs. Silicone-Like Resin: How to Choose the Right Shore Hardness for Functional 3D Printed Parts

A practical guide to comparing Shore 8A, 25A, 45A, 57A, 68A, and 52D flexible resin options for gaskets, soft grippers, wearable prototypes, medical simulation models, vibration dampeners, and rubber-like functional parts.

Published by QTS USA Editorial Team · Updated May 2026 · Category: 3D Printing Resins · Reading Time: 12 minutes

Need an ultra-soft, silicone-like 405nm resin? Start with QTS Flexible 8A for maximum softness and high elongation, then compare firmer QTS flexible resins when the part needs more shape retention, impact resistance, or industrial durability.

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Quick answer: Flexible resin is not one single material category. For functional resin 3D printed parts, the most important selection question is not only “Is it flexible?” but which Shore hardness, elongation, rebound, tear resistance, viscosity, and post-processing workflow match the real job of the part. Choose lower Shore A materials such as QTS Flexible 8A when the part must feel ultra-soft and silicone-like. Choose firmer QTS flexible resins when the part needs stronger support, repeated deformation, or industrial durability.

In this guide

1. What flexible resin and silicone-like resin really mean

2. Why Shore hardness matters for functional resin 3D prints

3. How to compare QTS 8A, 25A, 45A, 46A, 57A, 68A, and 52D flexible resins

4. Best applications for silicone-like, rubber-like, and TPU-like resin

5. Printing, washing, and post-curing tips for flexible resin

6. FAQ and references

What “Flexible Resin” and “Silicone-Like Resin” Really Mean

In resin 3D printing, the words flexible, rubber-like, TPU-like, and silicone-like are often used together, but they do not always describe the same material behavior. Some flexible resins are still relatively firm. Others bend well but do not feel soft. A smaller group of advanced formulations is designed to feel closer to silicone or soft rubber, with lower Shore A hardness, higher elongation, and stronger elastic recovery.

That difference matters because a resin used for a soft robotic gripper is not the same as a resin used for a snap-fit bumper, a gasket, an RC tire, or a wearable pad. The best resin is the one that gives the printed part the right combination of softness, stretch, rebound, tear resistance, surface finish, printability, and long-term durability.

Practical definition: A good silicone-like resin should not simply bend. It should feel soft under compression, stretch without tearing too easily, recover after deformation, and remain printable on common 395–405nm LCD, DLP, MSLA, and SLA resin printers.

QTS USA positions its resin lineup as premium 3D printing resins and filaments made in Taiwan with fast U.S. shipping. The QTS USA resin portfolio includes standard, clear, dental, high-resolution, engineering, high-temp, castable, water-washable, and multiple flexible materials ranging from ultra-soft silicone-like options to tougher rubber-like and TPU-like materials. [1]

Why Shore Hardness Matters for Functional Resin 3D Prints

Shore hardness is one of the most useful numbers when comparing flexible materials. Apple Rubber explains that Shore durometer is used to measure the hardness of polymers, elastomers, rubbers, and plastics, with higher numbers indicating harder materials. Intertek describes Shore Hardness ASTM D2240 as a method for determining the relative hardness of soft materials by measuring the penetration of an indenter under defined force and time conditions. [4] [5]

For flexible 3D printing resin, Shore A is generally the scale users should compare when evaluating soft, rubber-like, and silicone-like materials. Shore D is normally used for harder, more rigid materials. This means a Shore 8A resin and a Shore 52D resin can both belong to a “flexible” family, but they will feel dramatically different in the hand and behave differently under load.

Practical rule: Lower Shore A values feel softer and more silicone-like. Higher Shore A values feel firmer and more rubber-like. Shore D values usually indicate a much stiffer, more engineering-style flexible material with stronger shape retention.

How to Compare Silicone-Like, Rubber-Like, and TPU-Like Resins

A common mistake is choosing flexible resin only by the word “flexible” in the product title. For functional parts, the better approach is to compare Shore hardness, elongation at break, tensile strength, viscosity, rebound, and target application. A very soft resin may feel excellent for wearable pads or medical simulation models, while a firmer resin may be better for repeated mechanical load, tires, bumpers, and industrial pads.

Ultra-soft silicone-like resin: Shore 8A

This is the best direction when a part needs a very soft, squishy, high-stretch, high-rebound, silicone-like feel. It is especially useful for medical simulation models, soft robotic grippers, flexible connectors, cushioning pads, soft-touch prototypes, wearable pads, and anatomical models.

Recommended QTS product: QTS Flexible 8A UV Resin, positioned by QTS USA as an ultra-soft Shore 8A silicone-like resin with 500–700% elongation and ultra-low viscosity. [2]

Soft rubber-like resin: Shore 25A

Choose this direction when the part must remain soft but needs more support than ultra-soft silicone-like resin. Typical applications include buttons, seals, anti-slip feet, soft grips, shock-absorbing pads, and wearable prototypes that need both comfort and structure.

Recommended QTS product: QTS Flexible 25A High-Resilience Rubber-Like UV Resin.

Industrial rubber-like resin: Shore 45A, 46A, and 68A

Choose this direction when the part needs firmer rubber-like behavior, stronger shape retention, traction, compression recovery, or industrial durability. These materials are better suited for grommets, dampeners, tooling pads, RC tires, grip parts, and impact-absorbing components than very soft 8A materials.

Recommended QTS products: QTS Flexible 45A, QTS Flexible 46A Transparent, and QTS Flexible 68A Heavy-Duty.

TPU-like elastic resin: Shore 57A

Choose TPU-like resin when the part should behave more like a durable elastic engineering prototype than a soft silicone pad. It is a good direction for flexible housings, robust prototypes, bendable covers, end-use-like validation parts, and functional components that need elasticity plus stronger form retention.

Recommended QTS product: QTS Flexible 57A Professional TPU-Like Elastic UV Resin.

Slow-rebound memory resin: Shore 52D

Choose a slow-rebound memory resin when the part needs controlled compression, cushioning, damping, and a slower return after deformation. This is a specialized direction for foam-like prototypes, compression pads, ergonomic prototypes, and parts where the recovery profile matters as much as flexibility.

Recommended QTS product: QTS Flexible 52D Slow Rebound Memory UV Resin.

Best Applications for Soft, Flexible, and Rubber-Like Resin

The strongest sales opportunity for flexible resin is not only hobby printing. U.S. customers search for flexible 405nm resin because they want to solve a real product-development problem: prototype the feel of rubber, silicone, foam, or TPU without waiting for tooling.

Application selection cards

Wearable prototypes

Choose low Shore A materials when comfort, skin contact feel, stretch, and compression recovery matter. Ultra-soft silicone-like resin is especially valuable for wearable pads, straps, cushions, and ergonomic test parts.

Gaskets and seals

The material must deform enough to seal, but it also needs enough tear resistance and shape recovery to survive installation. QTS Flexible 8A is useful for very soft seals, while firmer 25A to 68A options can be better when the seal needs more structure.

Soft robotic grippers

Grippers need repeated bending and recovery while protecting delicate objects. Low Shore A, high elongation, and strong rebound are important for flexible fingers, suction-like contact pads, and compliant end-of-arm tooling.

Medical simulation models

Training models often require tissue-like tactile response, not just dimensional accuracy. Silicone-like resin helps labs and educators validate soft-touch anatomy, pads, and practice models before moving to molding or production.

Vibration dampeners and pads

Impact and vibration control depend on both softness and rebound behavior. Softer resin can help with cushioning, while firmer rubber-like grades may support more load and longer service life.

RC tires, grips, and industrial pads

These parts usually need traction, repeated deformation, abrasion tolerance, and longer service life. A firmer rubber-like resin such as 45A, 57A, or 68A is often more appropriate than an ultra-soft silicone-like material.

Printing and Post-Processing Tips for Flexible Resin

Flexible resin can require more careful handling than standard rigid resin. Because soft parts can deform during printing, users should pay attention to orientation, support density, cleaning time, and post-curing conditions. The goal is to create enough support for print success without leaving excessive support scars on the final flexible surface.

Before printing

Shake the bottle gently but thoroughly and confirm printer compatibility with 395–405nm resin. Uniform resin mixing improves exposure consistency and mechanical performance.

Support design

Use higher-density supports for very soft parts, especially tall, thin, or complex geometries. Soft materials can flex during peel forces, increasing the risk of distortion or print failure.

Cleaning

Clean thoroughly without over-soaking. QTS recommends 95% IPA for 3–5 minutes for Flexible 8A, which helps remove uncured resin while reducing unnecessary stress on very soft printed parts. [2]

Post-curing

Use controlled UV post-curing. QTS recommends water-submerged curing for Flexible 8A for 5–10 minutes to reduce surface tackiness and improve final feel. [2]

Surface finishing

For a soft, professional feel, QTS suggests a light dusting of talcum powder for Flexible 8A. This can improve touch feel and reduce perceived tackiness on ultra-soft printed parts. [2]

Safety reminder: As with all photopolymer resins, users should wear gloves and eye protection, provide ventilation, avoid skin contact with uncured resin, and follow the resin safety data sheet and local disposal requirements. Flexible prints may feel friendly after curing, but uncured resin still requires professional handling.

Why QTS Flexible 8A Is a Strong Choice for Ultra-Soft Silicone-Like Parts

QTS Flexible 8A stands out because it targets an extremely soft zone that many general flexible resins do not reach. QTS USA lists the material at Shore 8A, 500–700% elongation at break, 1.0–1.5 MPa tensile strength, 70–100 cps viscosity at 25°C, and 395–405nm wavelength compatibility. For users who have tried “flexible” resin that still feels too stiff, this difference is commercially important. [2]

The low viscosity is also meaningful. Many flexible resins are thick, slow to drain, and harder to clean. QTS USA specifically emphasizes Flexible 8A’s ultra-low viscosity as a benefit for faster printing, easier cleaning, and improved detail capture. For U.S. customers using common LCD resin printers, a softer resin that is also easier to process can reduce frustration and support repeat purchasing. [2]

Quick selection summary

Choose QTS Flexible 8A when the part needs maximum softness, silicone-like feel, high stretch, wearable comfort, medical simulation softness, soft grippers, or squishy prototypes.

Choose QTS Flexible 25A when the part needs a balance of softness and structural rebound, such as buttons, pads, grips, seals, and flexible functional prototypes.

Choose QTS Flexible 45A, 57A, or 68A when the part needs more shape retention, impact resistance, traction, or industrial durability instead of maximum softness.

Choose QTS Flexible 52D when the part needs a slower rebound profile for cushioning, damping, memory-like compression, or specialized foam-like prototypes.

Ready to Print Softer, More Functional Parts?

Build flexible prototypes that feel closer to the final product.

If you need a 405nm flexible resin that can create ultra-soft silicone-like prototypes, QTS Flexible 8A is designed for creators, engineers, labs, and product developers who want softness, stretch, low viscosity, and reliable processing in one material. Explore the QTS USA flexible resin lineup and choose the Shore hardness that fits your real application.

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FAQ: Silicone-Like and Flexible 3D Printer Resin

What is silicone-like 3D printer resin?

Silicone-like 3D printer resin is a flexible photopolymer resin designed to imitate soft silicone or rubber behavior. It is used when a printed part needs softness, stretch, compression, rebound, or a soft-touch feel rather than rigid plastic behavior.

Is flexible resin the same as TPU?

No. TPU is a thermoplastic material often used in FDM printing or industrial polymer processes. TPU-like resin is a photopolymer resin that attempts to simulate some flexible, rubber-like, or elastic behavior. The exact performance depends on the resin formulation, Shore hardness, elongation, post-curing, and print geometry.

What Shore hardness is best for soft grippers and wearable prototypes?

For very soft grippers, wearable pads, and silicone-like prototypes, lower Shore A values are generally preferred. QTS Flexible 8A is designed for ultra-soft silicone-like performance with Shore 8A and high elongation, making it suitable for parts where softness and stretch are the main goals. [2]

Why do some flexible resin prints feel tacky after curing?

Surface tackiness can come from insufficient cleaning, oxygen inhibition during curing, under-curing, or resin-specific behavior. QTS recommends water-submerged post-curing for Flexible 8A for 5–10 minutes to help eliminate surface tackiness, followed by optional talcum powder finishing for a professional soft feel. [2]

Can QTS Flexible 8A be used with common resin printers?

QTS USA states that Flexible 8A is compatible with 395–405nm LCD, DLP, and SLA printers and lists common printer brands including Phrozen, Anycubic, Elegoo, Creality, and Prusa. Users should still run exposure calibration on their specific printer and layer height. [2]