ME 232:
Additive Manufacturing
From Fundamentals to Applications

Additive manufacturing (AM) also known as 3D printing is an emerging technique for direct conversion of 3D computer aided designs into physical objects using a variety of approaches. AM technologies are simple and flexible processes that allow for the creation of very complex and customizable 3D objects in just a few process steps. This class gives an overview of available processes, explains their underlying physical principles and discusses current research. Students will get to know how AM can change the way we prototype and manufacture products in the future.
By the end of the course, students will have gained the skills and knowledge to demonstrate the following objectives:

AM Technologies
Know advantages and disadvantages of AM (additive) to other manufacturing technologies (subtractive). Describe the differences between different AM techniques (liquid, solid powder and sheet based).
AM process chain
Know the generalized process steps involved to produce a 3D printed part. Follow the guidelines for process selection. Perform basic designs on CAD software, create slices using the STereoLithography (.STL) file format and upload them into AM control software. Know the limitations and problems of .STL files and perform basic manipulations. Discuss alternatives for STL that integrate capabilities of modern printers.
Design for AM/ Topology Optimization
Know the Design For AM (DFAM) rules. Leverage opportunities in shape, hierarchical, functional and material complexity amenable to AM. Customize geometry, create integrated assemblies eliminating conventional constraints. Create unique approaches to product design improving product performance, creating entirely new functionality while cutting manufacturing and assembly costs. Know the limitations of conventional software packages and get to know novel AM specific software.
Extrusion
Describe the principles of extrusion based additive manufacturing. Describe the temperature based and chemical based approaches to control the material state. Get to know the most widely used systems and explore bioplotting based on the same fundamental principles. Calculate process parameters such as the velocity of material flow and bonding strength using simplified assumptions.
Photopolymerization
Describe the constituents of a resin used in stereolithography. Know the fundamentals of free radical and cationic photopolymerization. Describe the reaction mechanism and design of photoinitators, monomers and formation of polymer network. Calculate reaction rates, required irradiance and exposure times. Know about scan patterns and different technologies on the market as well as their capabilities.
Powder Bed Fusion
Describe powder bed fusion mechanisms: solid state, chemically induced and liquid phase sintering as well as full melting. Name power handling and recycling strategies. Discuss the advantages and disadvantages of electron beam and laser based powder bed fusion processes and describe the processable materials. Calculate simplified stationary melt pool formation characteristics. Discuss deposition strategies, capabilities and limitations as well as machines on the market.
Material Jetting
Explore the technology that derives from the conventional 2D printing process that is now extensively investigated in academia and industry. Get to know the evolution of this technology, current machines and principles, available materials and technical challenges. Describe the drop on demand and the continuous mode droplet formation strategies. Model the process based on conservation of energy considerations.
Sheet Lamination
Describe sheet lamination bed processes based on gluing and adhering. Describe thermal, clamping and ultrasonic consolidation based processing. Name applicable materials for each process as well as advantages and bottlenecks of technology. Calculate process parameters for different techniques and materials. Discuss microstructure and mechanical properties and get an overview of machines on the market.
Direct Write technologies
Describe different technologies that can create two or three dimensional functional structures directly onto flat or conformal surfaces in complex shapes without tooling or masks. Discuss ink based, laser transfer, thermal spray, liquid phase, beam tracing and beam deposition. Name applicable materials and calculate process parameters like speed and curing depth. Discuss process parameter- microstructure relationships, benefits and drawbacks as well as machines on the market.
Mechanical property prediction
Know how AM requires the need for different design criteria accounting for geometrical discontinuities/features. Get an overview of the yet limited knowledge in mechanical property assessment and prediction of AM materials. Understand why this limitation still impedes the full utilization of the unique features of AM and prevents this technology from being injected effectively into every-day manufacturing practices.

Text: Ian Gibson, David W. Rosen, Brent Stucker: Additive Manufacturing Technologies: 3D Printing, Rapid Prototyping, and Direct Digital Manufacturing

Prerequisites: Calculus (MATH 43), Basic Physics (PHYSICS 55), Basic Thermodynamics (E30 or ME140), Basic Chemistry (CHEM 31a and b) or equivalent.

Further details at Stanford University