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Instructions for Use (IFU) for Ultra Gloss and Transparency

This document provides application-specific instructions for achieving ultra-gloss surfaces and high optical transparency using 3Dresyns® photopolymer resin systems.

This IFU must be used in conjunction with:

This document does not replace the general IFU and applies only to workflows targeting surface finish and optical clarity.

Scope of application

This IFU applies to:

  • Printing of transparent or translucent parts
  • Applications requiring high surface gloss or optical clarity
  • SLA, DLP and LCD vat photopolymerization systems

This IFU does not apply to:

  • Inkjet or powder-based technologies
  • Applications where surface finish is not critical
  • Non-photopolymer materials

Nature of gloss and transparency in photopolymer printing

Ultra-gloss and transparency are process-dependent outcomes, not intrinsic resin properties. Final optical performance depends on:

  • Resin formulation and version
  • Pigmentation level and additives
  • Printer technology and exposure strategy
  • Printing orientation and layer thickness
  • Post-processing and post-curing workflow

Small variations in processing conditions may significantly affect surface appearance and clarity.

Why common cleaning methods reduce transparency

Most freshly printed parts lose gloss and transparency and become hazy, translucent, or whitish when cleaned with isopropanol, ethanol, or even with our milder Cleaning Fluid Bio.

Alcohols such as ethanol and isopropanol also significantly reduce the mechanical properties of most clear and colored prints, weakening them and increasing brittleness. Learn more: Comparison of different methods for cleaning and post-processing 3D printed resins.

Printing considerations

To maximize gloss and transparency:

  • Use thinner layer thicknesses to reduce layer stepping
  • Orient parts to minimize visible layer interfaces on optical surfaces
  • Avoid unnecessary support contact on critical surfaces

Overexposure may increase yellowing or haze, while underexposure may reduce surface quality.

Exposure and curing considerations

Exposure parameters must be calibrated to:

  • Achieve sufficient curing without excessive overcure
  • Minimize light scattering and internal defects

Excessive curing energy may increase surface roughness or optical distortion.

Required equipment

  • Wash & Cure unit (≈100 €), such as Wash & Cure Machine, or equivalent, for cleaning and light post-curing
  • Thermal oven (optional, required for Method 2)

Cleaning and post-processing methods

The following methods are cost-effective, fast, and reliable for achieving maximum gloss, transparency, mechanical strength, and safety. Do not cut corners.

Method selection

  • Method 1 is fast and easy but typically provides slightly lower transparency than Method 2.
  • If 100% transparency without polishing is required, proceed directly to Method 2.

Method 1 – Light box post-curing of wet prints (dipping in cleaning fluids)

Features

  • Uses Cleaning Fluid UNW1 Bio or Cleaning Fluid UNW2 Bio
  • UNW1 Bio: ultra-low viscosity, maximum clarity (not recommended for intraoral use unless fully removed)
  • UNW2 Bio: medium viscosity, odorless, higher biocompatibility
  • Both fluids are MSDS hazard-free

Relative risk of haziness

Isopropanol ≅ Ethanol > Cleaning Fluid Bio > NW1 Bio > UNW2 Bio > UNW1 Bio (best)

Process

  • Remove prints from build platform and cut supports
  • Wash prints in UNW1 Bio (RT) or UNW2 Bio (≈50 °C) with gentle stirring
  • Transfer prints to fresh cleaning fluid and light post-cure for 15–60 minutes
  • Remove residual cleaning fluid by lightly spraying isopropanol

Method 2 – Light box post-curing of dry prints (air atmosphere)

Method 2 provides the highest transparency, as no cleaning fluid contacts the fresh print surface.

Features

  • Gravity-driven resin removal in a thermal oven
  • Ideal for high-transparency optical parts

Process

  • After printing, remove supports and place prints upside down in an oven at 50–65 °C for 15–60 minutes to allow uncured resin to drip out
  • Avoid temperatures >65 °C to prevent yellowing
  • Post-cure dry prints in a light box for 15–60 minutes per side
  • Remove residual surface stickiness by spraying isopropanol

Final cleansing for biocompatible devices (Methods 1 and 2)

  • Thermal dipping in UNW2 Bio at 70–100 °C for 20–30 minutes
  • Thermal dipping in water at 70–100 °C for removal of hydrophilic extractables

For full details, read: IFU for biocompatible resins.

Handling and contamination control

Optical surfaces are sensitive to dust, fingerprints and surface contact. Clean environments and careful handling are recommended throughout processing.

Validation and quality control

Users should validate optical performance by visual inspection under controlled lighting and, when applicable, by measuring surface gloss or light transmission. Reproducibility requires consistent processing and documentation.

Limitations and responsibilities

Ultra-gloss and transparent outcomes are highly sensitive to processing conditions. Users are responsible for validating surface quality for their application, qualifying post-processing workflows and ensuring suitability for end-use requirements. 3Dresyns does not assume responsibility for surface appearance obtained under user-defined workflows.

Summary

  • Maximum gloss and transparency require controlled post-processing
  • Higher temperature reduces required cleansing time
  • Some resins tolerate boiling temperatures, others require gentler conditions
  • Biocompatible parts must be fully cured and free of extractables

Reusing dirty Cleaning Fluid

Expose used cleaning fluid to sunlight or light box curing to polymerize residual resin. Filter cured particles using a paint filter. The filtered fluid can be reused multiple times.

Relationship to other Instructions for Use

This IFU must always be used together with any specific Instructions for Use (IFU). In case of discrepancy, the most application-specific IFU prevails.

Governing principle

Ultra-gloss and transparency in photopolymer printing are multivariable, process-driven outcomes. Final optical performance depends on formulation, printing parameters and post-processing conditions and must be validated by the user.