Some of the ways these drawbacks are being tackled are;
Poor Surface finish ; Electron beam process can polish a material on the fly when a small amount of argon is added to process, when more surface deformations are present this polishing process maybe time consumming.
Removal of printed support structures Electron beam based process can also electron beam machine the part removing structures more cleanly once part has been cleaned of excess powder, though it will create a heat effected zone.
Printed part deformation due to residual stress this is normally only a problem in the first number of layers, so dummy material is added to reduce this in the part, also post printing layer scanning electron microscope measurement of the part and analytical software may be used to reveal size of distortions prior to fitting. Post process electron beam machining may also be applicable though this process creates a surface heat effected zone.
Inconsistency of material structure within part More consistent heat history via analytic shape to heat print control profile software, powder consistency metrics may help.
Difficulty of applying post printing thermal treatments of parts needed for some specalist apllications, part can be heated with beam prior to quenching in oil baths.
Time consuming process of testing each metal powder for consistency of printing on standard metalicarap, requiring hundreds of repeat prints, to enable a statistical reliability profile to be gathered, enalbing a validation certificate for powder and process on a particular design of machine, so as to be suitable for safety critical metal part applications. Currently the aero space industry have validation for over 6000 metal alloys, on many diffent processes/machines. Printing on a single machine only a couple of materials could be validated each year.
Slow speed of printing (0.2Kg per hour) , Eventually a 10Keuro to 15K euro MetalicaRap kit could fit in the home enviroment where speed of printing is not such a problem.
Edited 2 time(s). Last edit at 09/27/2014 12:21PM by rapatan.
