Porosity and density problems
High porosity in metal 3D printed items can directly influence their mechanical qualities and lower their density. Either inadequate or too much energy during the printing process could be the cause of the porosity, or problems with powder production technique. High loads cause high porosity parts to break or suffer other damage easily.
Reversal of stress residual
Common aspects of metal 3D printing are heating and later cooling. Residual strains arising from this severe heat change could cause issues including deformation, cracking, and warping that would affect the manufacture of parts. Usually found in the contact area between the printing component's bottom and the printing bed, the rather concentrated area of residual stress is
Unbalanced microstructure
Uneven microstructure of metal components produced by 3D printing could influence their general performance. Heat treatment can help to some extent solve this issue, but it cannot provide microstructure like that of heat-treated forgings or castings.
Cracking and distortion under the heat treatment process
Because residual stress releases, metal components could crack and distort during heat treatment. Especially in the chilling stage, shrinkage-induced edge curling deformation and cracking is rather noticeable.
Reaction plan
Control printing settings and choice of materials.
Purchasing premium raw material suppliers and optimising printing settings like laser power, scanning speed, etc. can help to lower the porosity of metal parts and guarantee proper melting of the metal. Choosing powder materials with spherical particles might thus raise the density of produced products.
Advancement of Technology in Heat Treatment
One of the main ways to improve microstructure and release residual stress is heat treatment. Residual stress can be efficiently lowered by means of binder burning and sintering, stress relief, hot isostatic pressing (HIP), austenitization (and quenching), and tempering, hence strengthening and toughensing the parts. Strict management of the heating and cooling rates throughout the heat treatment process helps to prevent cracking and deformation brought on by either too rapid or too slow rates.
Supporting Framework and Preheat Approach
Using an appropriate support structure can help to lower residual stress generation and stop warping of the parts following printing. Moreover, preheating the building ingredients and the printing bed helps to lower temperature gradients, hence lowering residual stresses. Reducing the scanning distance and breaking the scanning region into smaller sections-known as "islands"-helps one to achieve the preheating method.
After therapy, surface roughness improves.
Usually post-processing for metal 3D printed items is powder and support removal, heat treatment, and surface polishing. Machining, grinding, or polishing can help to raise surface roughness by means of respective operations. Concurrently, surface roughness problems can be somewhat reduced by adjusting printing parameters like layer thickness and laser power.
Material investigation and technological creativity
Metal powder producers are actively creating new materials to fulfil certain needs such moulds in reaction to the poor welding performance of often used quenched and hardened materials in metal 3D printing. Concurrently, mould makers are investigating how to enhance 3D printed moulds' performance by means of later treatments including heat treatment. Furthermore, metal 3D printing technology will be merged with more advanced technologies as intelligent and digital manufacturing technologies grow to support the growth of mould manufacturing towards greater efficiency, higher accuracy, and less cost.
https://www.china-3dprinting.com/metal-3d-printing/high-performance-car-parts-by-3d-printing.html