Case Study: Resin Removal in Emerging 3D Print Technologies
To find a safer solvent for cleaning up a variety of resins used in emerging 3D printing technologies.
Many companies are now using a 3d printing process known as DLS (Digital Light Synthesis), developed by Carbon Inc. and also known as Continuous Liquid Interface Production (CLIP).
This 3D printing process is used to produce finished parts and components at scale with excellent mechanical properties, resolution and surface finish.
The resins used to manufacturer parts in the DLS printing process include urethanes, epoxies, silicones, and more
Companies that have adopted 3D printing technologies like DLS use solvents to remove these resins and clean finished parts.
One of the primary cleaning solvents used by manufacturers to clean parts in 3D printing is isopropyl alcohol (IPA).
IPA works effectively. Yet it is a fast evaporating, highly volatile and flammable solvent, presenting serious workplace safety and compliance concerns.
Additionally, at smaller volumes, IPA is expensive to purchase and not easy to recycle due to its nature as a volatile solvent.
Due to these concerns, we were approached by a handful of companies using DLS and looking to switch to a cleaning solvent other than IPA with safer physical properties and lower cost at small volumes.
Safer, low-VOC solvents have been used in other 3D printing and additive manufacturing processes during post-processing resin removal.
For example, propylene glycol ethers, such as dipropylene glycol monomethyl ether (DPM) and tripropylene glycol monomethyl ether (TPM), are often used as safer alternative solvents to remove resins in 3D printing.
These glycol ethers are most effective when used on stereolithography resin (SLA) during post-processing and prior to a final IPA rinse.
Yet the range of resins used in DLS 3D printing is wider, presenting additional cleaning challenges for replacing straight IPA.
When we were approached by engineers from companies using the DLS process for 3D printing, including Carbon, Google X and Ford Motor Company, they were looking for a different solvent with strong cleaning properties and enough versatility for the broad mix of resins they use to produce parts.
We started by looking at our selection of alternative solvents, ultimately focusing on dimethyl ester based solvent systems.
Product name: Sta-Sol® ESS 165
Chemical name: Dimethyl Adipate
CAS NO: 627-93-0
Physical Properties: Clear liquid
Markets & Applications: Solvent, paint remover, chemical intermediate, coatings, cleaning agent, bonding agent, adhesives.
Packaging: Available in 5 gallon pails, 55 gallon drums, totes and bulk
And our chosen cleaning solvent for 3D printing, Sta-Sol ESS 165, has a high concentration of dimethyl adipate.
As with any solvent, there are still physical hazards associated with the use of a straight solvent like ESS 165.
But, when compared to straight IPA and many conventional solvents with higher volatility, Sta-Sol® ESS 165 provides a non-flammable, low VOC and generally safer primary cleaning step. A final IPA rinse is still recommended, but the overall usage is significantly reduced.
Due to its nature as a slow evaporating, low vapor pressure solvent, ESS 165 also makes it easier to reuse and recycle the solvent, making it generally more cost-effective than solvents like IPA.
After requesting samples and conducting testing, our customers have determined that Sta-Sol ESS® 165 is a safer solvent with excellent polymer cleaning and removal properties for a broader range of resins used in emerging 3D printing technologies such as Digital Light Synthesis.