Changing Technology

Another Technique to Color Finished SLA Parts

While one company is implementing conversion kits on their 3D printers (see 5-Star, page 8), DSM Somos, New Castle, DE, has discovered a way to add color to finished stereolithography (SLA) parts so that customers can have prototypes that perform like the end-product and closely match it in color.

In the past, prototypers colored parts by using commercial, water-based dyes. However, this method did not work universally or uniformly on all resins and would sometimes deform the part due to prolonged soaking in the hot solution. Now, by applying aniline-based dyes in non-aqueous solutions -- also known as leather dyes -- complete and consistent coverage in a variety of aesthetically pleasing colors can be achieved.

Somos found that aniline-based leather dyes in an alcohol solvent penetrate the surface of prototypes made from DSM Somos 7100, 8100, and 9100 series resins, making the color more permanent. The process is, however, partially reversible by rinsing the parts in acetone or alcohol after dyeing.

Basic materials needed to dye SLA parts include the dye, rubber or plastic gloves, a stiff-bristled brush and paper towels. The job is completed in six steps:

• If the part is small, dip the prototype into the dye. For larger parts, apply the dye to the part using a brush or the applicator contained in the dye bottle.
• Remove excess dye from the part by dabbing it with paper towels.
• Once excess is removed, use the brush to uniformly distribute dye on the surface of the part. The brush is also useful for applying the dye into small crevices and corners.
• Let the part dry for a few minutes.
• One it is dry, rinse the part under a gentle stream of running water to eliminate any residual dye.
• Dry the part again with paper towels. It is now ready to be handled.

Leather dyes are sold in various quantities, usually ranging from four ounces to five gallons. Readers can reach leather dye suppliers, offering a variety of colors, from the DSM Somos website.

--KC

For more information: Circle 522 - DSM Somos, or connect directly to their website via the Online Reader Service Program at http://www.1rs.com/012df-541