What changes will result if we additive manufacture the bracket instead of machining it. Your colleague, Molly Bedenum from the design department has produced a topologically optimised bracket design as shown in below
Rick asks you which of the three possible metal AM processes would be best for the part: Selective Laser Melting (SLM), Laser Metals Deposition (LMD), or a recently developed process called Bound Metal Deposition (BDM) by a company called Desktop Metal. Which process would you recommend for this application?
The new design of bracket can be manufactured by any additive manufacturing process, but the material limitation has limited it to just three of the below mention process. Now best of them has to be recommended based on how it will manufactured product means pre-processing, processing and post processing. Other than this the process will also be evaluated on working principal/pattern and what advantages and limitations they have in processing the new design of bracket.
1. Selective laser melting SLM
2. Laser Metal Deposition
3. Bound Metal Deposition
Selective laser melting will manufactured the bracket in two simple steps, first a layer of powder is spread on the machine table and then a laser will print a 2D shape of product by melting (that solidifies instantly) the power of desire shape. Laser metal deposition complete this in single step where a power is melted at the nozzle outlet by a laser and then spread by nozzle in a specific shape on the table. Similarly, bounded metal deposition also melts a binding material mixed with powder to deposit a layer of material on machine table.
Selective laser melting and laser metal deposition does not need any specific post processing process other than cleaning and surface finish if required but bounded metal deposition required binder curing process and melting process in furnace. Surface finish of the laser metal deposition is low as compared to selective layer deposition due to highly converged laser beam which only melts the metal where required in very controlled manner where laser metal deposition spread a paste of metal whose flow or spread cannot be controlled once it leave nozzle.
Selective Laser milting, laser metal deposition and bounded metal deposition processes are very similar is terms of depositing the material to manufactured the bracket that is 2D layers of metal is deposited to develop a 3D product but steps in achieving this are very different. Is selective laser melting table used based moves downward with each layer finished where a new layer of powder is deposited which is then metaled by laser to create new 2D layer of metal where laser only moves on 2D plan. Laser metal deposition method use little complex approach where nozzle remain fixed in vertical position and table moves with six degree of freedom to deposit material layers. Bounded metal deposition work by depositing layers of material on static table and heat moves with 3 linear degree of freedom 3DOF.
Advantages and Limitations
Selective laser melting use laser which does not involve much of movement as compared to other two process means machine working is simple understand. Ability of this process to use multiple laser to manufacture one part or use each laser to manufacture multiple parts at once is most prominent feature which other two process lack. This makes an effective production rate of this machine for high volume batch production. Laser metal deposition seems to be the fastest process available with minimum steps required and fast speed of table and laser as compared to selective laser melting and bounded metal deposition but working of this process seems difficult to understand as compared to other two processes due to 6DOF required by table to manufactured product. Bounded metal deposition seems simple as compared to other two processes but number of steps involves in post processing make this process least favorite for this process due to high production rate.
So based on above discussion selective laser melting can be recommended as best process available for new bracket design as it has simple working process, less steps involve, processing multiple parts at once, high production rate and low or no post processing required.