As published by the United States Patent and Trademark Office, the application from Apple for “Method and apparatus for three dimensional printing of colored objects” describes a simple 3D colour printing machine capable of producing multicoloured structures. Although such printers exist, most are made as professional industrial and prototyping tools, with even “affordable” models priced as much as a well-appointed car.
Apple’s suggested system is based on modern 3D printing technology, which makes 3-dimensional items by depositing layers of material – mostly plastic – onto a platform as defined by a digital image file. Majority of solutions heat and squeeze ABS or PLA filament through a motorized print head attached to support bars, a setup that enables movement along X,Y and Z axes.
Generally, present consumer 3D printers with linear feed mechanisms are restricted to single colour creations. Switching out filaments is possible, but the process is barely ideal and may not lead to high quality prints.
Apple suggests a system that uses two print heads, one for applying colour and one for depositing material. In a few embodiments the colour head is aligned parallel with the material head on the same support bar, and some other iterations place the colour head on a separate side support. Both layouts require colour to be applied while the material print head sprays liquid to solid material on a moveable platform.
Suitable procedures for colour application include multicoloured markers, spray nozzles, inkjet technology and airbrushes.
In one 3D colour printing model, the print head deposits a layer and moves up and out of the way as the colour head approaches to add a layout of colour. Another model has the print head complete the print before the colour application head comes into position for paint application. A moveable platform enables an assist in Y-axis movement.
An alternative way of 3D colour printing includes a rotatable colour application nozzle that can move 360 degrees around the print head. This allows both heads to be active simultaneously. A mechanical arm is used in another model, which again refines efficiency.
Apple continues to detail different colour processes, such as a possibility to sand, buff or otherwise complete a 3D object before adding colour.
It is still unclear if Apple plans to bring such an intricate device to market, but the language of the patent does not include any references to home use.
Apple’s 3D colour printing patent application was first filed for in May 2014 and credits Howard A. Miller and Geoffrey Stahl as its inventors.