The new Clear Cast Resin from Formlabs for high-precision, low-labor industrial investment casting

We are pleased to announce the new Formlabs material “Clear Cast Resin”, specially developed for industrial investment casting. The 3D printing workflow using Clear Cast Resin and Formlabs Stereolithography (SLA) enables the direct production of casting models in-house. This reduces costs and shortens throughput times. It also improves flexibility in iteration and production.

Models made of Clear Cast Resin offer precision foundries a clean burnout with low ash content and no metal traces. This is complemented by first-class thermal expansion and a maximum deviation of 0.25 mm compared to the design. In addition, foundries can immediately integrate the material into their workflow; they do not need to change their investment or burnout process.

3D printing for industrial investment casting

One of the most important applications of large-format industrial SLA printers is the direct 3D printing of investment casting models. In the 1990s and 2000s, 3D printer manufacturers also introduced new technologies such as material and binder jetting, which enabled the production of models made of PMMA and wax. This allowed models made from such materials to be easily applied to conventional casting trees during the pre-casting process.

The use of 3D-printed models reduces the overall cost per part, as the high up-front costs for tool production are eliminated. This allows them to produce small to medium production runs or manufacture parts with complex geometries that would be impossible or prohibitively expensive to produce conventionally. Many foundries immediately recognized the advantages of 3D printing for industrial investment casting. However, they were not in a position to use some of the technologies in-house.

Although the conventional large-format printers used to produce investment casting models are technically impressive, they usually cost hundreds of thousands of francs. In addition, a specialized technician is usually required to operate and maintain them. Due to the cost and complexity of these systems, this technology is prohibitively expensive for many small and medium-sized foundries. Many companies therefore outsource the 3D printing of their models to service companies, which increases the cost per model and lengthens lead times.

Formlabs materials for investment casting

Formlabs already has many years of experience in the production of photopolymers with a low coefficient of thermal expansion (CTE) and clean burnout. The Formlabs material manufacturer Spectra has been producing resins for the investment casting industry for over ten years.

Formlabs has been offering various materials for the jewelry industry for years. These are wax-filled materials that are designed for casting in a muffle. These include Castable Wax Resin and Castable Wax 40 Resin, which offer good burnout results and a simplified workflow compared to traditional lost wax casting.

However, these materials are too fragile for larger foundry customers. For the larger, thicker and more structurally robust parts required for industrial metalworking, a different material is needed. The solution for these customers is the combination of the outstanding accuracy, resolution and reliability of Formlabs SLA 3D printers with the technical performance of the new Formlabs Clear Cast Resin.

The new Formlabs Clear Cast Resin

Thanks to the new Formlabs Clear Cast Resin, small and large foundries can implement 3D printing of models inexpensively and easily in-house. Formlabs Clear Cast Resin has been specially developed for industrial foundries. In addition to a clean burnout, an extremely low ash content and an excellent surface finish, it offers above all high performance with a model accuracy of just 0.25 mm.

Beyond technical performance, Formlabs’ Clear Cast Resin gives foundries access to the easiest and most user-friendly 3D printing workflow. Within minutes, foundries can start their first print, even without technical training or 3D printing experience. They can then move on to more challenging tasks at their leisure. After a few hours, you will receive a finished, high-precision model. The reduced workload lowers the overall cost per part, a price advantage that you can pass on to your customers.

Very inexpensive 3D printers – usually FDM printers (Fused Deposition Modeling) – lead to poor surface quality of the parts. This results in inaccurate shapes and more work during preparation and post-processing. If foundries have experienced high upfront costs or poor quality, they may be reluctant to try a new printer or material. The simple workflow of Formlabs SLA printers together with Clear Cast Resin combines the quality of traditional, large-format SLA 3D printers with the price point and intuitiveness of available FDM printers. This allows industrial foundries to bring the technology in-house at a low entry cost. After minimal training on data preparation, they can start producing models immediately.

The use of clear cast resin

Formlabs works with its customers to develop products that help solve problems in a wide range of industries. In terms of industrial investment casting, this meant developing a resin that burns out cleanly, holds tight tolerances, has a low ash content and no traces of metals. At the same time, the 3D printer should hold tight tolerances, be affordable and offer an accessible workflow. The new Formlabs Clear Cast Resin, which can be processed on the Form 3+, Form 3L and Form 4, meets these high requirements in all respects.

Over the course of more than a year, Formlabs has worked with several beta testers to develop a workflow that can be used immediately by industrial investment foundries without any process changes.

What is the workflow for Clear Cast Resin?

1. With lattice structure software such as Materialise Magics*, you can hollow out your parts and add a lattice structure inside. This enables a cleaner and faster burnout with low ash content. It also minimizes the forces caused by thermal expansion, preventing cracking in the investment.
2. Upload your part with grid structure to PreForm. Then select your printer and the material Clear Cast Resin.
3. Start printing the component and leave the rest to the machine.
4. After printing, remove the part from the printer and wash it with Formlabs Resin Washing Solution, isopropyl alcohol (IPA) or TPM in the Form Wash for smaller parts and Form Wash L for larger parts.
   1. Make sure that no liquid remains inside the part and blow the resin and solvent out of the inside of the grid structure with compressed air.
   2. You may have to wash the parts twice, with the material being blown out in between and afterwards.
5. Then leave the parts to dry for at least 30 minutes. You can also use the Form Cure L with a preheating time of 30 minutes at 35 °C for this.
6. The parts are post-cured in the Form Cure or Form Cure L at 35 °C for 15 minutes.
7. To prepare the investment material, attach the parts to the casting tree.
8. Embedding in the investment is carried out by dipping the parts in investment in accordance with the usual work processes.
9. Burning out the parts takes two hours at 700-900 °C.
10. You can follow your conventional workflow for casting.

*Formlabs customers are entitled to a 35% discount on Materialise Magics. Request a trial version of Materialise Magics now to receive the discount.

Get started with the 3D printing of investment casting models

Use the Form Series SLA 3D printers with Clear Cast Resin and benefit from a “set and forget” workflow, industry-leading accuracy and clean burnout. This reduces the amount of work required in the pre-press stage and reduces the need for sanding or manual processing of parts afterwards. As a result, these 3D printed models lower your total cost per part. In addition, they offer new possibilities for product design without having to change the workflow.

Do you have any questions? Would you like more information or an individual sample component?
Then contact us!