Additive Manufacturing processes Flashcards
What is additive manufacturing in a nutshell(simple, qualitative terms)
A form of manufacturing that starts with zero material, unlike other forms which bend materials into certain shapes. It is a relatively new form of manufacture, really starting in the 1970’s
What are the disadvantages of additive manufacturing compared to subtractive methods?
- Lower accuracy, tolerances are about five times higher
- Harder to validate structural integrity- forging and casting create stronger structures
- Much slower speed, especially for simple shapes/geometries
What are the advantages of additive manufacturing compared to subtractive methods?
- Sustainable from a resources point of view: It uses material much more efficiently than subtractive manufacturing
- Much better to produce complex internal structures, e.g. a square hole.
- No additional complexity cot
- Flexibility in what can be made
- No set up costs
What materials can be used in additive manufacturing?
- polymers, metals, ceramics and paper. The types of manufacture are in part categorised by what material they use
Where does additive manufacturing stand in the market and what is it’s projected growth?
It makes up a small part of the market, but it is expected to grow about 15 percent annually as tech improves
What is Fused Filament Fabrication or Fused Deposition Modelling (FDM)
What materials are used as the filler?
it’s basically 3d printing- the filler material is usually in a spool, and the nozzle moves in an x-y plane. To account for the z plane, the platform that holds the part being manufactured moves down. Typically, there are at least 2 nozzles: one for support filling and one for build filling
Materials used- primarily polymers, but research into ceramics is being done: thinking about use in semiconductors
What is Jetted Photopolymer (J-P)?
Rather than being placed into a vat, resin is placed onto a build substrate similar to an inkjet printer. The resin is then finished via uv light and the support material is either water-jetted away or melted via heat
What is 3D printing?
It is similar to selective laser sintering- Except instead of using lasers to bond powdered build material, it uses adhesive. The powder is placed in a layer first, before adhesive is placed on the areas that want to be kept. At the end, the loose powder is vacuumed or removed.
What is selective laser sintering?
Very similiar to 3D printing, but instead a laser is used to melt powder into required shape. after each layer, the platform is moved down, more powder brushed on top and it is repeated
What is laminated object manufacturing?(LOM)
A sheet of material is unrolled onto the platform before a laser outlines and basically cuts it out to stick to the adhesive. After this the waste is rolled onto a waste roll. The platform is then lowered and the process is repeated.
What is inkjet printing?
Quite literally a “thing maker” where several nozzles- possibly in the hundreds, shoot material onto the construction surface. After dried, it is worn down with a milling head to ensure it is smooth. This is repeated until completion
What is Stereo-lithography?(SLA)
Liquid resin placed in a vat, and the platform sits just under the surface of this. The resin is photo-hardening, so light is shone onto the surface creating a thin layer of hardened resin. The platform then moves down and the process repeats
What are the two forms of metal additive manufacturing? What is the difference between the two?
“Powder Bed Deposition/technologies” and “Direct Energy Deposition”
Powder bed: There is quite literally a bed of metal powder that can be melted by lazers or other forms of energy. Similiarly, it can also be that the powder is i the nozzle, and the nozzle deposits powder that is to be melted, or powder that is already melted
What is electron beam melting?
Heating metal powder, before melting with an electron beam. Forms thicker layers with bigger particles than SLS
What is blown powder manufacturing?
In a nutshell, it is a form of additive manufacturing that literally blows the powder onto the body. Unlike other methods, the surface can be moved in all dimensions, so the nozzle has access to all surfaces and doesn’t have to built vertically. It is faster than other forms, but not as accurate. Also hard to collect waste powder to recycle
