Luximprint Design Guidelines

Our ‘Design Guidelines’ are intended as guidance for designers and engineers of novel lighting and high-tech systems. We aim to provide some ‘golden design rules’ to smoothen the ‘Design for Manufacture’ process in preparing the CAD file for use with our optical 3D printing process.

INTRODUCTION

The Luximprint optical 3Dprinting platforms are primarily engineered for the fabrication of large-format optics and Optographix. Typical printed optics solutions may appear as large sheet items or just single optics elements once smaller sizes are needed (separated from the substrate sheet).

BUILD TRAY SIZE AND LENS FORMAT

Size, feature height, materials and build volume are well-balanced to meet the most demanding applications. Further customization (beyond specs) is possible on demand, please contact our sales engineers to learn about the possibilities.

Luximprint image with build tray size and lens format

SUBSTRATE PROCESSING

The optical 3D printing process uses a substrate as a carrier for the optical features. After loading the substrate in the process (vacuum-table), optical structures can be added to both the top and bottom side of it, as such allowing for combined optical elements. After the application of the optical resins onto the sheet, substrate and resin merge into one solid item. A minor or large difference in refractive indices (‘n’) remains, depending on the substrate material as chosen.

Image explaining the dual-sided printing approaches in the optical 3D printing process of Luximprint

There is a variety of validated substrates available, including PMMA, PC, PET, and glass, among others. Processing of custom substrates and reworking of existing lens developments is possible on request.

DRAFT ANGLES / UNDERCUTS / OVERHANGS

In the Luximprint process, no additional support materials or structures are used. Instead, the full focus is on generating optically smooth surfaces straight from the 3D printer. To enable minimal deviations and proper processing, the following design guidelines are established:

Image explaining draft angles, undercuts and overhangs in the Luximprint optical 3D printing process

1) In combination with conventional CNC milling and turning methodologies, we may still be able to generate undercuts/hollows/overhangs. This would just extend the lead time by a few days.

CAD FILE FORMATS

Contrary to common 3D printing methodologies, the Luximprint process can only process high-accuracy CAD files (“solids”). As such, we refuse to work with Surfaces Testelation Formats (.STL), as any inaccuracies or triangular surfaces may get replicated in the printing (and hence need further correction), what we’d like to avoid.

Accepted CAD file formats are:

  • .STP (.STEP) files: STandard for the Exchange of Product model data. This standard is linked to ISO Standard 10303.
  • .SLDPRT/.SLDASM: Solidworks File formats. Often, we can also work with raw x_t formats instead: Parasolid Model Part files or modeler transmit files.
  • .IGS (.IGES): Initial Graphics Exchange extensions (ASCII-based textual format);
  • Specific XML formats, such as used – for example – in Photopia (.RAY);
  • Other common standards: please consult your Luximprint Design Engineer for a consult.

DOWNLOADS

For your convenience, a summary of this information is available for your internal technology library.
Feel free to download a summary of the latest Design Guidelines:

Download Design Guidelines

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DISCLAIMER
Please note these guidelines are reflecting our ‘average’ current technology state. They are intended as ‘golden-design-rules’ for optimization of your DFM process and generating the CAD-file.
As all the parts we fabricate at Luximprint are custom optics work, there is no ‘one size fits all’ manual available. As such, the displayed capabilities display the best values provided by a deep process understanding and past manufacturing history by our Printoptical Engineers. New developments might be well-underway, and we are always open for challenges that go ‘beyond specs’ and work under R&D Guidance. Please don’t hesitate to reachout to us directly in case of any questions!

Luximprint Material Specifications

Our ‘Design Guidelines’ are intended as guidance for designers and engineers of novel lighting and high-tech systems. We aim to provide some ‘golden design rules’ for their ‘Design for Manufacture’ process when it comes to preparing the CAD file for use with our optical 3D printing process.

INTRODUCTION

The Luximprint optical 3Dprinting platforms are primarily engineered for rapid prototyping of custom LED optics and Optographix. Our optical resins are developed for application in illumination and entry-imaging applications in engineering and temporary project environments. Suitability for use in outdoor environments and demanding applications is determined by market requirements.

MATERIAL CHARACTERISTICS

In the charts and graphics below, you will find the common Luximprint user definitions and material characteristics are displayed.

Image of Luximprint Material Specifications for explanation of materials used in the optical 3D printing process.

Image of Luximprint Optical Resin Transmission and Refractive Index Data

Note: Detailed visible light transmission data and refractive index charts (.xls) are available upon request for import in your custom optics design software library. Our materials can be used in nearly all common optics design packages, including Zemax, LTI’s Photopia, CodeV (Synopsis), TracePro (Lamda Research), among others.

Overview of Luximprint material properties for use in Material Specifications pages

Table input: Sample with 2.0 mm printed lens structure on 3.0 mm thick PMMA base substrate.

(1) Format: Larger sizes are available on request. Please also refer to our Design Guidelines for more details.
(2) Shape conformity: the difference between the CAD file and the actual 3D printed model. In fact, tolerances vary from only a few microns to tens or hundreds of microns depending on the feature to be printed. As all our work is custom, it is hard to display an exact figure here.

Please verify the accurate expectations with one of the Luximprint Sales Engineers.

APPLICATION EXAMPLES

For references and application examples of 3D printed optics, please refer to our Printed Optics Gallery or Printed Optics product sections.
Our showcases which are, for confidentiallity reasons only limited available, can be viewed in the Showcases section.

DOWNLOADS

Below you can download a summary of the latest Material Specifications.

Download Design Guidelines

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NOTE:
New and improved material implementations are road mapped, please contact our sales engineers to learn about the availability and possibilities for your custom project.

Luximprint Surfaces & Finishes

Our ‘Design Guidelines’ are intended as guidance for designers and engineers of novel lighting and high-tech systems. We aim to provide some ‘golden design rules’ to smoothen the ‘Design for Manufacture’ process in preparing the CAD file for use with our optical 3D printing process.

INTRODUCTION

In addition to generating optically smooth surface finishes as required for quality optics, the Luximprint process is capable of generating defined ‘Frosted Finishes’: matte textures with a variety of defined roughnesses.

SURFACE FINISH GENERATION

The table below provides some basic process information on how and where Frosted Finishes can be applied, and what other pre- and post-process treatments are available.

Chart demonstrating the Printoptical Process Capabilities of Luximprint pre-process, in-process and post-process

FROSTED FINISH DEFINITIONS

The charts below provide some generic surface information on the approaches and definitions of Frosted Finishes. Additional data for any of the finishes as available from our in-house material library can be provided, as well as their respective transmissive properties (.xls charts). Your Luximprint Engineering contact can provide you with the latest details upon request.

Image showing Luximprint capabilities related to Surfaces and Finishes measured with a High Pass Filter

Figure: Surface profile of some defined roughness patterns measured by a High pass filter (800 microns) conforms ISO 4287 standards.

Image with chart of Luximprint frosted finish demonstating deviations in profile roughness.

Figure: Profile roughness of Luximprint Frosted Finishes measured with a high pass filter for defining profile roughness conforms ISO 4287.

Typical Ra and Rz values are available from any of the patterns and are available upon request.

CORRELATION VALUES AND MOLD ROUGHNESS

The correlation between the units of measure used to define frosted surface finishes and how they compare to for example mold roughness is a commonly raised question. In Europe, the standard of measurement for defining mold surfaces may include Roughness Average (RA) and Root Mean Square (RMS), but elsewhere (such as in the US) the definitions as set forth by the Society of the Plastics Industry (SPI) might be used.

APPLICATION EXAMPLES

In the website section ‘Printed Diffusers‘ there is more information available on this particular topic, including application examples and its utility. The blogposts ‘Available now: 3D Printing Frosted Finishes‘ and ‘Optical 3D Printing Methodologies Enable easy Frosted Finish Application‘ shine more light on this interesting in-process feature that may add great value to new and existing lens developments for a variety of purposes.

SAMPLES

Reference Samples of Frosted Finishes are available in our Sample Shop. We have special sampling conditions in place for users adopting 3D-printed Frosted Finish solutions for their projects.

DOWNLOADS

Below you can download a summary of the latest ‘Surfaces & Finishes’ document.

Download Surfaces & Finishes