Assignment 03 PDF

## Assignment 03 **Ques:1: How shot peening can be used for stress relief and how does it differ from sand blasting?** **Ans: Shot peening is a cold work process used to impart compressive residual stresses onto the surface of a component, which results in modified mechanical properties.** The sho...

## Assignment 03 **Ques:1: How shot peening can be used for stress relief and how does it differ from sand blasting?** **Ans: Shot peening is a cold work process used to impart compressive residual stresses onto the surface of a component, which results in modified mechanical properties.** The shot peening process is used to add strength and reduce the stress profile of components. **How does shot peening work?** Shot peening works by striking a surface with a shot (round metallic, glass or ceramic particle) with enough force to generate plastic deformation.** When a group of shots impact the surface, they generate multiple indentations, resulting in the component being encased by a compressive stressed layer on the metal surface. **The main advantage of shot peening is to extend the service life of a component by creating an induced compressive stress layer to increase resistance to fatigue (including corrosion fatigue, stress corrosion and cavitation erosion) while also helping to resist the development and propagation of cracks.** **How shot peening differs from sand blasting** Sand blasting and shot peening are both surface treatments. Sand blasting involves spraying high-speed sand particles onto a metal surface to improve roughness and cleanliness. Shot peening and sand blasting are uses the same spray method, but shot peening spray round particles, but these particles are thrown out by a high-speed rotating impeller. | Processing | Abrasive | Spray method | Roughness | |---|---|---|---| | Sand blasting | Sand particles | Nozzle | Lower | | Shot peening | Spherical particles | Nozzle | Higher | **Ques 2: What is microcasting? What are specific applications of micro-casting?** **Ans: Micro casting, also known as lost-wax casting, employs sacrificial patterns identical to the geometry of the part to be produced in metal.** Sacrificial models, commonly known as coaxes, are made of special materials that are designed to liquefy and burn at relatively low temperatures and leave no ash. **Sacrificial models are used to make a structure known as a cluster in which the pieces are the grains of the cluster and the stalk is the feed channel for the molten metal. This wax structure is embedded in an inert material (plaster, wax or liquid ceramic) and then placed in firing.** During firing, the refractory solidifies and the waxes dissolve, leaving a cavity identical to the pieces with the casting system (a land steel investment casting). The result is a hollow shell that can be filled with aluminium or steel. **Specific applications of microcasting:** * **Breads, Caps, Knobs, Burners, cork supports, Tubs.** * **Aerodynamic applications:** * Distributors * Shut off valves * Control valves * **Construction of pumps:** * Pump body * Gameter carrier lantern * Impellers * Diffusers * Circulators * **Electromechanics:** * Engine shields * Inverter boxes * Street lights * **Automotive parts:** * Racing parts * Aluminium frames * Engine cylinders * Gear boxes * Engine crankcase ## Assignment 04 **Ques:1: What is STL tile? Write the problem associated with STL file in brief. Also, describe a valid and invalid Tessellated Model.** **Ans: STL (Stereolithography) is a file format widely used in 3D printing and computer-aided design (CAD).** It consists of an unordered list of triangular facets representing the outside skin of a 3D object, without any representation of color, texture or other attributes. **The STL file is a facet model derived from precise CAD models. It is, therefore, an approximate model of a part.** **Problems associated with STL file** Many commercial tessellation algorithms used by CAD vendors today are not robust, and as a result tend to create polygonal approximation models which exhibit the following types of errors: * **Gaps (cracks, holes, punctures) that is missing facets:** Tessellation of surfaces with large curvature can result in errors at the intersections between such surfaces, leaving gaps or holes along edges of the part model. * **Degenerate facets (where all its edges are collinear):** A geometrical degeneracy of a facet occurs when all of the facets’ edges are collinear even though all its vertices are distinct. Degenerate facets are less critical in STL and they seldom cause some serious build failure. * **Overlapping facets:** Overlapping facets may be generated due to numerical round-off errors occurring during tessellation. * **Non-manifold topology conditions:** These may be generated because of tessellation of more complex geometric entities. A valid model would be one whose facets have only one adjacent facet each that is one edge is shared by two facets only. **Valid Tessellated Model:** * A tessellated model is said to be valid if there are no missing facets, degenerate facets, overlapping facets, or any other abnormalities. * When a valid tessellated model is used as an input, it will first be sliced into 20 layers. * Each layer would then be converted into unidirectional (or 2D) scan lines for the laser or other RP technique to commence building the model. **Invalid Tessellation Model:** * A valid model is tessellated non-robustly and results in a gap. * If this error is not corrected and the model is subsequently sliced, the missing facet in the geometrical model would cause the system to have no predefined stopping boundary on the particular slice. * Thus the building process would continue right to the physical limit of the RP machine, creating a stray physical solid shell and ruining the part being produced. **Ques: 2: What is the need of AM software? Describe features of any four AM softwares.** **Ans: Additive Manufacturing (AM) Software is essential for the full potential of AM to be realized. It helps engineers create, adapt and manufacture 3D printed parts by providing instructions for each layer or voxel.** AM software is also necessary to ensure that the process happens without errors and to control and coordinate the entire product lifecycle. **Here are some types of AM software and their uses:** * **CAM(Computer Aided Manufacturing) software:** Provides instructions for producing parts layer by layer. * **Process monitoring software:** Ensures that the AM process happens without errors. * **MES (Manufacturing Execution Systems) software:** Controls and coordinates the entire product lifecycle, from quotation to final use. * **PLM (Product Lifecycle Management) software:** Digitizes and controls the entire product lifecycle. * **3D and CAT scanning software:** Analyzes parts non-disruptively. * **Part finishing software:** Requires adequate software and accurately studied design methods. * **Slicing tool path generation:** Generates g-code, that tells the printer each layer to print. * **Printer interface:** Provides essential information to the user about material level, print status, error notifications etc. **Features of AM Software** **Materialize Magics Software:** * **Import file formats:** Magics can import many standard CAD formats, as well as packages like Sketchup, and lattice structures. * **Repair and modify:** Magics can restore, modify and improve 3D files with features like automated repair, offsets, machine. * **Generate reports:** Magics can generate automated reports to monitor builds and ensure consistency. * **Nest parts:** Magics can arrange parts on the smallest possible area with a single mouse click. * **Analyze builds:** Magics can identify possible issues to prevent expensive build failures. * **Build time estimation:** Magics has a build time estimator to help determine how long a part will take to print. * **Apply textures:** Magics can apply textures and graphics to specific surfaces of a model. **Materialise Mimics Software:** * **3D Modelling:** Mimics can create 3D anatomy models by segmenting medical image data. * **3D printing:** Mimics can print 3D reconstructions using AM technology. * **Image processing:** Mimics can enhance the visualization of foreign objects in 3D. * **Workflow Animation:** Mimics can automate repetitive steps using Python scripting. * **Data security:** Materialise is committed to protecting user data and ensuring it is securely managed. * **AI-enabled segmentation:** Mimics can segment and label CT scans of patients with metal implants, osteoarthritis and osteophytes. **Solid Viewer Software:** * **Viewing:** Solid viewer software allows users to rotate, pan and zoom 3D models. * **Sharing:** Users can share designs with others by sending secure links or emailing images. * **Markup:** Users can mark-up models directly in a browser to get feedback from stakeholders. * **Collaboration:** Users can collaborate on designs without the need to download extra software or viewers. * **Publishing:** Users can send a no-cost 2D/3D player along with their designs. * **File formats:** Solid viewer software can read a variety of 2D and 3D formats, including SLDPRT, SLDASM, STL, OBJ, STEP etc. **Velocity 2.0 Software:** Velocity 2.0 is a software platform with features that help engineering teams improve their software’s quality and speed, keeping sprints on track. Some of its features include: * **Customization:** Users can customize reports, algorithms, thresholds, and permissions. * **Productivity drivers:** Velocity 2.0 can help teams understand what drives their productivity. * **Innovation Speed:** Velocity 2.0 can help teams improve the speed of innovation. * **Software quality:** Velocity 2.0 can help teams improve the quality of the software they deliver. * **Sprint Tracking:** Velocity 2.0 can help teams keep current sprints on track. * **Bottleneck prevention:** Velocity 2.0 can help teams prevent future bottlenecks. * **Team and organizational objectives:** Velocity 2.0 can help teams support their team and organizational objectives.