Powder Additive Manufacturing

INTRODUCTION

“Ever wondered why some very simple parts are disproportionately expensive?”

Normally it’s because the production of the parts is very difficult and time consuming therefore, they are produced in small batches. This also includes the cost of making the molds, which is very high, and it cannot be spread over different required shapes.

The Additive Manufacturing (AM) is one of the remarkable recent technology in which a 3D object is produced by the layer-upon-layer method. This methodology is completely different than the conventional manufacturing techniques such as forging or casting from metal stock. For this process, different powders, printers, and processes are required, depending on the applications. All parameters, such as feeding, flowing, packing, electrostatics, etc., must be carefully synchronized. This is the only way to ensure that the final produced component has the desired characteristics, the process achieved reliable results, and cost-effective.

ADVANTAGE OF ADDITIVE MANUFACTURING

Additive manufacturing processes offer a range of benefits over conventional methods of manufacturing.

The benefits are as follows:

  • Flexibility in design changes
  • Multiple parts can be built as one
  • Less time required
  • Complex shape, inner cavities or lattice structure can be produced

VARIOUS ADDITIVE MANUFACTURING TECHNIQUES

Various Additive Manufacturing techniques are available in the market. Following list provides information about the current and future Additive Manufacturing techniques:

  • Binder jetting: An Additive Manufacturing process in which a liquid bonding agent is selectively deposited to join powder materials.
  • Directed energy deposition: A process in which focused thermal energy is used to fuse materials by melting as they are being deposited.
  • Material extrusion: In this process material is selectively dispensed through a nozzle or orifice.
  • Material jetting: Droplets of build material are selectively deposited.
  • Powder bed fusion: In this AM process thermal energy selectively fuses regions of a powder bed.
  • Sheet lamination: An AM process in which sheets of material are bonded to form an object.
  • Vat photopolymerization: An AM process in which liquid photopolymer in a vat is selectively cured by light-activated polymerization.

THE IMPORTANCE OF POWDER QUALITY IN ADDITIVE MANUFACTURING

Typically, Additive Manufacturing involves 3D modeling software, along with the layering material, such as a powder (metal, polymer, ceramics, etc.). The software is used to produce a computer-aided design (CAD), from which the Additive Manufacturing equipment reads, allowing it to lay down the powder. Additional layers of the powder are then introduced, added in a layer-by-layer fashion to ‘build up’ the 3D object. The powders used are combined with heat – delivered via laser – to fuse the powders into a solid form. It is required to use the material in powder form because it is not possible to ‘spray’ a molten metal accurately/evenly.

The quality of the powders used in the Additive Manufacturing is incredibly important because these powders will impact on the physical properties of the finished product. For instance, the powder will play a crucial role in shaping the product’s tensile strength/brittleness, impact resistance, heat tolerance and resistance to corrosion. Improvement in the qualities of the powders will help to increase the number of products that can be made. The powder quality can be well understood by using the powder characterization instruments developed by GranuTools such as GranuDrum, GranuCharge, and GranuPack.

GranuDrum instrument is used for the re-coater speed optimization. GranuCharge for the re-usability of powders, and GranuPack for the information of part porosity and surface roughness.

With the right equipment, any fears can be allayed that a powder is unsafe or nonsuitable and that it is of the required standard to produce items that can make a real difference.

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