Question

Clearly identify and explain the reason behind the key processing limits relevant to the material extrusion process - FDM (Fuse deposition modelling) that are based on:

a. Limits of the material being processed

b. Limits of the equipment being used

Answer 1

The Fused Deposition Modelling (FDM) process constructs three-dimensional objects from the 3D CAD data. A temperature-controlled head extrudes thermoplastic material layer by layer. A thin layer of plastic cools and hardens and a layer is formed. Once a layer is completed, the base is lowered usually by about one-sixteenth of an inch — to make room for the next layer of plastic.

a) Generally different materials are available with different trade-offs between strength and temperature properties As well as acrylonitrile butadiene styrene (ABS)polymer,polycarbonates,polycaprolactone, polyphenylsulfones and waxes. A "water-soluble" material can be used for making temporary supports while manufacturing is in progress, this soluble support material is quickly dissolved with specialized mechanical agitation equipment utilizing a precisely heated sodium hydroxide solution. Since we see that only thermoplasts material are used but it limits us to only a particular type of material but we can not use materials like metals or ceramics.

b) constant pressure and in a continuous stream are required in this process. This pressure must be kept steady and at a constant speed to enable accurate results. temperature control or through the use of chemical agents is used for bounding material layer. Material is often added to the machine in spool form as shown in the diagram. layer thickness, orientation, raster angle, raster width and air gap are the parameters to to kept in control and effort is made to optimize it.