Four years after its launch, MakerBot's main problem is meeting the demand for its affordable 3D printers. "We thought it would be a technology that took a while to catch on -– or at least a few months. We were wrong. We sold out in days and we are still working really hard to keep up with demand," said CEO Bre Pettis. Next in the lineup is a scanner that will allow those with little design experience to scan objects and duplicate them in 3D.