RAPID MANUFACTURING 0F METAL COMPONENT BY LASER FORMING

A SEMINAR REPORTONRAPID MANUFACTURING OF METAL COMPONENT BY LASER FORMING

PRESENTED BYMAYANK KHANDELWAL1209141028

SEMINAR CO-ORDINATOR Mrs. NEELAM KHANDELWAL

RAPID MANUFACTURING OF METAL COMPONENT BY LASER FORMING

1 Introduction2 Definition of RM3 Types of laser4 laser-equipped layer manufacturing techniques for fabrication of metal component 4.1 selective laser sintering4.2 selective laser melting 4.3 3-D Laser cladding 5 Conclusion

CONTENT

The direct fabrication of metal component by laser forming technique in a layer by layer fashion.These technique directly fabricate layer by layer physical model produced in CAD . They are also called additive manufacturing, digital manufacturing or e-manufacturing.The capability of producing several physical model in short time directly from computer solid model helped to shorten the production development steps.

INTRODUCTION

The physical input into the RP system are the material , CAD model and laser.It is a one step process in which tooling is eliminated therefore production time and cost is reducing.The process is suitable for production those material which is difficult to process and fabricate (complex parts) to high aggregate value.DEFINITION OF RM

ApplicationIt is used in automotive and aerospace industries.It is used to fabrication of prostheses.

METHODS OF RM

Most of the RP machine use CO2 or Nd-YAG laser in continuous mode.The laser power in the range of 50-500 W but very high power CO2 laser up to 18 KW are also used.The wavelength of Nd-YAG laser and CO2 laser used is 1.06 m and 10.6 m.The absorptivity of most metals increases by decreasing the wavelength.TYPES OF LASER

Nd-YAG laser is more prefer than CO2 laser:-

.Nd-YAG laser have a large melting depth for the same power density because of the higher absorptivity..Nd-YAG laser resulted in a higher density and a deeper sintering depth..

Pulse laser is more effective for DMLF in powder in bed methods.By using pulsed laser, very good metallurgical bonding between the tracks and layer is obtained.Very less heat effected zone is produced. Pulse laser is more effective than continuous laser

In this process a thin layer of powder is first deposited from one cylinder onto the part-build area.The laser beam guided by the galvano mirrors is scanned onto the powder bed to form solidified/sintered layers.Then another powder layer is deposited.The cycle is repeated until the 3-D part is complete.The fabrication chamber is closed and the process is performed in an inert atmosphere (nitrogen or argon) to avoid oxidation.Selective laser sintering

Fig. 3. Illustration of the selective laser sintering process.When mixed powders are used, the powder of low melting point is melted and acts as a binder. The process is also called direct metal laser sintering (DMLS).

The surface roughness of the parts is mainly influenced by the powder particle size.The smaller the particle size, the thinner the layer thickness, and the higher the surface quality exhibited by the as-sintered part.The principle was to consolidate the interior of a component to 80% or higher density and the outline (surface) of the component to a density exceeding 92%.This method can produce fully dense parts of mechanical properties close to the wrought material. Table 3 displays

Fig. 4 shows the process and the fabricatedpart of tungsten.

SLM is very similar to SLS in terms of equipment but uses a much higher energy density, which enables full melting of the powders.The fabricated parts exhibit a density very close to the theoretical one.A Nd-YAG laser of maximum peak power of 3 kW and maximum average power of 50W is used.The laser light is guided through the optical fibre.the laser beam diameter is 0.8mm focused onto the powder bed.

Selective laser melting

The laser head is attached to the x2y table controlled by a computer. The main machines in the market that use SLM are Trumaform LM 250, MCP Realiser and LUMEX 25C.

Fig. 6. MCP Realiser: (a) SLM building principle; (b) dental caps and crown made of titanium; and (c) airbone structure made of stainless steelThe equipment is used for the fabrication of ultra light mesh structures in pure steel for permanent bone replacement purposes in a project (EPSRC).

The MCP Realizer is also used for the production of dental caps, crowns.

The 3-D laser cladding process is also known as laser generating.Instead of fusing material in a powder bed, the powder is delivered in a gas jet through nozzles.The powder is usually delivered coaxially with the laser beam.The metal powder is fused in the focal zone of a high-energy laser beam and parts with complex geometries can be formed.Fully dense parts with mechanical properties close to the conventionally processed material.

3-D LASER CLADDING

The process is also called laser engineered net shaping (LENS).

The production of end-use parts made of metal is one of the most promising applications for these techniques.Direct fabrication of metal products of high density and excellent mechanical properties is possible by using laser-based layer manufacturing techniques.The aeronautic, automotive and medical industries are the main markets.CONCLUSION