Spectra Launches Three New Materials for 3D Printing Audio Applications

Spectra Audio materials

Spectra Photopolymers, an affiliate of Formlabs, has launched three audiology materials that are specifically optimised for DLP 3D printers. These materials have been formulated not only to provide superior mechanical performance, but also for a shortened post-processing workflow.

audiology earpieces

“With the April launch of Spectra Audiology materials, labs now have access to a set of materials that offer characteristics that outperform what is available today. We understand that some manufacturers have already made an investment in 3D printers, so we believe that we can also bring the benefits of our experience in material development to DLP printing technology. This has been proven by the rapid adoption of our Spectra EasyCast Resin by a number of the big five major hearing aid manufacturers, who now benefit from a reduced post-processing workflow”

– Iain Mcleod, Director of Audio, Formlabs

Customers who have already invested in DLP 3D printers, such as those from Asiga or RapidShape, are now able to 3D print in Spectra’s EasyCast, JetBlack and ImpactClear materials. All these materials have years of proven success within the hearing aid industry by one of the major manufacturers, and these materials are now available for use to anyone in the industry.


The Hearing Aid Digital Journey

The hearing aid industry was one of the early adopters of digital workflows for mass customisation, where SLA, DLP, and SLS printing technologies are all used to print hearing aid shells and earmoulds. Given application similarities for noise protection, communication, and custom earphones, very few labs today are still using only traditional production techniques to make custom fit products for the ear. 

With the launch of Formlabs Form 3B 3D printer in 2019, SLA continues to contribute as a key printing technology due to its affordability, print volume size, and highly detailed prints. Many labs today employ Formlabs printing technology to provide a large proportion of hearing aids to clinics and institutional health services such as the NHS in the UK. Similarly, DLP printing technology also captures a share of the market due fast print speeds, making manufacturers and labs now able to choose their preferred technology.

Formlabs’ acquisition of Spectra Photopolymers in 2019 added bio-compatibility expertise and a large ISO 13485 facility to help Formlabs develop the future of 3D printing resins. Spectra had already been successfully supplying biocompatible materials to both SLA and DLP printing technologies, including DLP printers operating at the more common 385nm wavelength, before the acquisition.

Spectra Audiology Material Portfolio

Spectra provides three DLP materials for Audiology, each formulated to provide unique benefits to the industry.

Spectra EasyCast

Spectra EasyCast

Cast material for production of soft silicone earmoulds and eartips

Top 3 benefits: 

  1. No release agent required
  2. Identification of air pockets 
  3. Easy to break
Spectra JetBlack

Spectra JetBlack

Biocompatible hard acrylic material for earmoulds and shells

Top 3 benefits:

  1. Deep black color
  2. High print detail
  3. Fast print speed
Spectra ImpactClear

Spectra ImpactClear

Biocompatible hard acrylic material for earmoulds and shells

Top 3 benefits:

  1. High drop survivability
  2. Crystal clear transparency
  3. High print detail

Spectra believes in providing hearing aid manufacturers attractive looking end-use parts, which is especially relevant in current trends of hearing aids and consumer earphones looking more alike. For example, demand for Spectra’s JetBlack has significantly increased due its deep black color profile similar to high-end consumer earphones to help reduce the stigmatisation of wearing hearing aids.


Taking a deeper dive into Spectra EasyCast material, this resin is used to print a sacrificial cast which is then filled/injected with silicone. Once the silicone has cured, it is broken apart, producing a soft custom fit eartip for hearing aids, earphones, or noise suppressor plugs. 

This process is outlined in detail in the free Formlabs white paper, 3D Printing Custom Silicone Ear Molds, but can be summarised in the following workflow where the traditional five steps in handling material parts are now reduced to three:

Step 1. Resin is filled in a DLP 385nm 3D Printer and the print job is started.

Step 2. Parts are then rinsed in 99% Isopropyl Alcohol to remove any excess IPA. A wash unit with an agitator, such as a FormWash, is recommended as this ensures the insides of the cast are washed also.


Skipped Step. Parts do not need to be cured in a UV nitrogen filled curing unit.

UV nitrogen filled curing unit

Skipped Step. With Spectra Resins, users also do not need to coat the casts with a release agent. The silicone should not bond to the cast.

The inside of the cured casts are coated with a release agent to ensure silicone does not bond to the cast

Step 3. Casts are filled with silicone and cured, optionally in a pressure polymerisation unit

3D printed earpiece

Spectra Easycast offers four unique advantages:

1. Does not require a release agent. For many cast resins, a release agent is required to stop the silicone from bonding to the wall during curing. Applying the release agent takes time to ensure it covers the inside of the cast and is allowed to dry before filling with silicone. This step is not required when using EasyCast, saving up to 30 minutes from the process and the cost of the release agent material.

2. Compatible with all silicones. Some silicone materials come out ‘sticky’ when the cast is peeled away, which is not the case with Spectra EasyCast. This means that it is fully compatible with more silicones available in the industry.

4. Easy to break. Once the silicone has cured inside, breaking the cast apart should be done carefully to ensure the silicone is not torn or damaged. Fishing pliers are commonly used, but this can also be done easily by hand with Spectra EasyCast.

3. Enhanced air bubble identification. Feedback has shown that a slight blue tint color helps identify bubbles that may have formed inside the cast when filling with silicone. This is a crucial quality control step, otherwise the bubbles will result in cavities on the surface of the final product which both affects performance and visual appeal.

Industry-Leading Resin Accuracy

From hearing aids which let patients fully experience the world around them, to high-end custom in-ear monitors for musicians who need to hear music in crystal clear clarity, performance and comfort are top of the priority list for earphone manufacturers. Inaccuracies in the printing process can cause multiple problems. Parts that are too large will be uncomfortable and offer poor sound quality, while parts too small can fall out of a users’ ear. Spectra Audiology materials have been formulated to retain the accuracies captured during the scanning, modelling, and printing processes. 

Start Printing Today

Spectra are offering free printed parts and resin samples, and these can be shipped globally. Contact our sales team here to request free printed parts, sample resin or for more information.


Spectra ImpactClear and Spectra JetBlack are compatible with common sterilization methods. 

All Spectra resins are manufactured in our ISO 13485 facility with accompanying SDS documentation. TDS documentation is available on request, along with build styles for a selection of DLP printers.