Prototyping Functional, Optically Transparent Light Pipes

Company: Nix Sensor Ltd.

Industry: Product Design

Profile: Ontario-based Nix wants to turn color into a digital experience. The Nix Pro Color Sensor, as well as the Nix Mini Color Sensor, aim to open up new markets for color sensing with easy-to-use, affordable handheld devices.

Challenge: Light pipes and other optically transparent components can be difficult to prototype. Methods like CNC, laser cutting, and making molds each had different limitations in achievable translucency, possible geometries, or turnaround time.

Solution: Nix used Formlabs Clear Resin to 3D print transparent components like lenses and internal light pipes in-house, saving time and cost compared to other methods like outsourcing CNC machined parts or laser cutting acrylic.

Results:

  • Nix reduced costs from $150-300 per part for CNC light pipes to just a few dollars per part using Formlabs Clear Resin.
  • Parts that previously required a minimum turnaround time of 3 days when outsourced could be fabricated in 2-3 hours using in-house desktop stereolithography 3D printing.
  • Light pipes printed on Formlabs 3D printers replicated the properties and tolerances needed to channel light in prototypes as would be necessary in the final parts, manufactured in PMMA.

Profile

Color can have a massive influence on how we interpret the world around us, but most of our communication around color is achieved verbally or via arbitrary standards and naming schemes. The way most of us think of color is analog, but Ontario-based Nix wants to turn color into a digital experience.

Lab grade tools already exist to sense color accurately, but these tools are only available to a limited market because of their price point and learning curve. The Nix Pro Color Sensor, as well as the Nix Mini Color Sensor, aim to open up new markets for color sensing with easy-to-use, affordable handheld devices.

Since launching their product, Nix has seen their sensors adopted for applications ranging from custom makeup tailored to the user’s skin tone to quality control for egg yolks and salmon before they hit grocery shelves. They’ve even received a Red Dot Design Award.

The Nix Pro Color Sensor and Nix Mini Color Sensor are easy-to-use, affordable handheld color sensing devices.

Challenge

Choosing the right fabrication method and material for many rounds of prototyping can be complicated. This is especially true of translucent parts like lenses and light pipes, which require tight tolerancing and optically transparent materials. For Nix, options included laser cut acrylic, CNC acrylic, 3D printed molds, and directly 3D printed plastics.

With laser cut acrylic, the material was clear, but could only produce 2D extruded shapes. With CNC machined acrylic, surfaces became cloudy so they couldn’t achieve the desired internal reflection unless the team polished parts with toothpaste or flame. They could 3D print molds, but this process took a long time.

Initially, Nix opted for outsourcing CNC parts. Even though they had their own CNC machine in the office, it was difficult to achieve the cuts they needed for the small, intricate light pipes. For each prototype, this CNC process took three to five days, and cost per part sometimes ended up being hundreds of dollars.

A light pipe is an optical fiber or a solid transparent plastic rod for transmitting light from an LED mounted on a printed circuit board (PCB) to the user interface of a device.

Solution

Nix has been using Formlabs 3D printers from the beginning, starting with a Form 1+ alongside a CNC machine when the company was based in a 10x10' bedroom. 3D printing light pipes in Clear Resin meant that they could print 10 different lenses on a single build platform in an afternoon, instead of waiting days between iterations.

For each version, the process starts with CAD software and ends with a finished prototype for testing.

The Form 2, a stereolithography 3D printer, prints parts by curing a liquid photopolymer resin with a highly precise laser.

First, the team creates a new light pipe design, or set of designs, in CAD. They import the design into Formlabs PreForm print preparation software and make sure it’s optimally oriented and supported for successful printing. If needed, the team can lay out multiple lenses on a single build platform.

Printed parts are removed from the build platform and washed thoroughly in isopropyl alcohol (IPA) using the Formlabs Finish Kit or Form Wash.

After printing, parts are washed thoroughly in isopropyl alcohol (IPA) using the Formlabs Finish Kit or Form Wash. The parts are then polished using Novus 1 acrylic cleaner. To sand the parts, the team places sandpaper on a piece of cork board that has some give, and swirls the lenses in a random pattern to avoid marks on surface. The grit of the sandpaper is increased until the parts are polished to satisfaction.

Parts are polished using Novus 1 acrylic cleaner to achieve optical transparency.

During sanding, Nix places sandpaper on a piece of cork board and swirls in a random pattern, gradually increasing the sandpaper’s grit.

Results

Using the Form 2 and Clear Resin, Nix was able to easily fabricate functional, optically clear parts for their prototypes in-house.

“Formlabs Clear Resin helped us analyze the shape, design, and fit of transparent components. There wasn’t really any other option other than to 3D print in Clear.” - Matthew Sheridan, CEO & Founder, Nix Sensor Ltd.

With the previous CNC method, fabricating these components took a minimum of three days, with each part costing between $150 and $300.

Using Formlabs 3D printers, the team was able to shave that down to only two to three hours per run (with the ability to print several light pipes per run). Additionally, material costs were lowered to only $0.32 per part using Clear Resin.

Application CNC 3D printing on the Form 2
Functional light pipe prototype Cost $150–300 $0.32
Lead Time 3–5 days 2–3 hours

A functional light pipe prototype, 3D printed on the Form 2.

Using optically transparent parts prototyped in Clear Resin on the Form 2 stereolithography 3D printer, Nix was able to speed up their product development cycle, bring cost per part down from up to $300 to $0.32, and ultimately bring an award-winning color sensor to market.




Nix Sensor Ltd.’s Toolkit:

Formlabs Form 2
Clear Resin
Form Wash

Buy Now Request a Sample Part




Nix Sensor Ltd.’s Toolkit:

Formlabs Form 2
Clear Resin
Form Wash

Buy Now Request a Sample Part

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