3D Printing with Multiple Materials and Colors

The smartphone you are intent on keeping hold of seems just as intent on slipping from your grasp. There’s scarcely a phone that has not been dropped—some of them several times. You only have to crack the glass once to invest in some protection, so it's no surprise that smartphone cases are a billion-dollar business.

One company has made it its life work to protect smartphones against unfortunate falls and the elements. OtterBox gets its name from the furry, cute marine mammal that opens shellfish while floating on its back in the Pacific Ocean—shellfish that are closed and usually safe from harm, like your smartphone should be.

We are here at OtterBox because the maker of “clam shells” for your iPhone has been using the latest Stratasys printer, the J750, to create prototypes of its case designs. While the J750 only recently became officially available, OtterBox has been playing with a pre-production machine for the better part of a year.

Brycen Smith of OtterBox praises the Stratasys J750, especially the ability to print multiple colors on a single part.

The company can’t get enough of it! Brycen Smith, who maintains and schedules 3D printing at OtterBox, said the printer saves the company bundles of money. Its “product-matching prototypes” are a game changer, he said.

Smith pointed out one of OtterBox’s cases, which has three different colors. 

That used to take three days to make, Smith explained. Each color was hand-applied and then you had to wait for the paint to dry. The J750 will make it in half a day. 

The Stratasys J750 combines full color 3D printing with multiple materials. (Image courtesy of Stratasys.)

The J750 claims photorealistic colors—up to 360,000 of them. If you are used to drab gray or simply beige samples from 3D printers, it will seem like rainbows have come out of the clouds. Colors on the few sample pieces we saw were bright and varied.

MCOR was the last 3D printer company to brag about its colors, but the vivid colors of J750 look quite a bit brighter that what we have seen on the paper-based MCOR machines.

The J750 also can handle multiple materials. Its supply consists of 16 cartridge bays. Six different materials can be used in the part with one more material, a water soluble one, which is devoted to creating the support structures. Stratasys’ previous multiple-material printer, the Connex, had three material choices per part.

The clear part of one iPhone case was first made on a Stratasys 3D printer. The same case also has opaque materials, but the entire prototype model can be made in one pass. Another example, a miniature running shoe, was printed with hard plastic uppers while the sole was made out of a flexible elastomer. Again, both materials were created in one pass.

Another improvement to the J750 is the surface finish. The precision has been increased to 14 µm. “We used to have to sand down prototypes,” said Smith. “Now we can use them as is.”

Sure enough, the rough stair steps that some printers produce and are easily visible to the naked eye are not apparent in the J750 models.

Stratasys is offering the J750 with a three-year warranty that even includes print heads and labor.

Nobody does this, according to Stratasys.

Clearly, Stratasys wants to be seen as a reliable production machine. OtterBox uses the J750 for 750 to 1,000 parts a week. Speed improvements have let Smith promise internal designers a 24-hour turnaround on each part.

Pricing was purposely not provided by Stratasys for the J750. However, Stratasys did indicate it would be less than the Objet 1000 and  more than the Objet 500 Connex3. This would put the J750 somewhere between $607K and $339K, which are prices estimated for those two printers by industry expert Terry Wohlers  in the 2015 Wohler's Report. 

The J750 3D printer can print gradient color with a range of materials and texture for “product-matching” model. (Image courtesy of Stratasys.)
Multiple colors and materials used in OtterBox smartphone case prototypes.
Under the hood of the Stratasys J750 showing the print heads in process of making multiple various smartphone covers.