Thermoplastic Powder Material

Thermoplastic materials are widely used for engineering and consumer products. These materials, therefore, are particularly attractive for prototyping, because they are typically also used in the final manufacturing method. 

Powdered sugar Poly(vinyl alcohol) Polyureic formaldehyde Wheat paste Methyl cellulose Powdered wood glue Water putty Maltodextrin Sodium silicate Alkaline polyphosphates Carbonates Polycarbonates Gum arable Alkaline lignosulfonates 

Expansion cement Fly-ash Patching cement Rapid setting cements Portland cement Hydraulic cement Reinforcement fibers Sake Fiber mesh Fly-ash Poly(vinyl alcohol) fiber Carbon fiber 

A thermoplastic powder has been adapted for 3D printing. The powder includes a blend of a thermoplastic particulate material, and an adhesive particulate material, with the adhesive particulate material being adapted to bond the thermoplastic particulate material when a fluid activates the adhesive particulate material. 

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J.R Bredt, S.L. Clark, D.X. Williams, and M.J. DiCologero, Thermoplastic powder material system for appearance models from 3d printing systems, US Patent 7 569 273, assigned to Z Corporation (Burlington, MA), August 4, 2009. 

Different rapid prototyping machines use different materials within a limited range. Some examples of materials are thermoplastic resins, polycarbonate, wax, powdered materials, plastics, and metals. Depending on the materials chosen and type of machine involved, you ll also have to perform other set-up steps that shouldn t require much time. 

Canadian Patent No. 2,278,688 [88] discloses a thermoplastic composite material 50-60% of which is polyethylene or polypropylene, 10-30% of which is wood powder, and 10-35% of which is a silicate (mica). 

The starting material in these process is not necessarily in the liquid state also polyvinyl chloride (PVC) pastes (plastisols) can be used, as well as even a well-flowing thermoplastic powder [17]. The particles will melt when in contact with the heated wall and will form a compact layer of material. The softened powder sticks to the wall, and other particles gradually complete the shaping process. Only the outer surface of an article made this way will be smooth, which is not objectionable for many applications. 

In powder coatings the coating material is applied to the workpiece in the form of dry (i.e., solvent-free) thermoplastic or thermosetting powder. The powder particles are heated and melt to form a film. The thermoplastic powders melt and fuse on heating whereas the thermosetting powders also become chemically cross-linked. Two main application processes are used electrostatic spraying and fluidized-bed coating. 

Among the particulate organic fillers, wood meal is the most important material for use in thermoplastics, in particular PP. For curable molding compounds, powdered cellulose is also in this category. These finely powdered materials are actually fibrous, finely ground and specially conditioned products based on spruce or beech wood or cotton. Others include wood granulate, sawdust, shell and seed meal and, already mentioned in relation to impact modifiers, natural rubber. 

Thermoplastic fusible adhesives (see Hot melt adhesives) may be used in the production of adhesive-bonded non-wovens, as powders, fibres or sheet films. The formation of strong bonds between the fibres occurs as the softened thermoplastic adhesive material resolidifies on cooling. The amount of adhesive incorporated in the web governs the strength of the fabric. 

L Ye, V KlinkmuUer, K Friedrich. Impregnation and consolidation in composites made of GF/PP powder impregnated bundles. J Thermoplastic Composite Materials 5 32-48, 1992. 

Both thermosetting and thermoplastic powders can be applied by powder coating processes. (See Table P.9.) Elaborate reclaiming systems to collect and reuse oversprayed material in electrostatic spray powder systems boost flansfer efficiency. Since the enhancement of the air quality standards this method has grown markedly. 

Reinforced fibers with thermoplastic polymers in form of powder belong to two categories. In the first method a polymer hose surrounds the fibers and the polymer powder (Fig. 7.15). Both hose and the not fixed powder material consist of the same polymer. The second method is to strew powder over the fibers. Thereby the polymer is temporarily heated in order to adhere to the fibers. 

As a general rule, self-reinforced composites consist either of layers of highly-oriented thermoplastic textiles [4-7] or of a combination of self-reinforced textiles and a similar thermoplastic matrix material, which is added in the form of a film, powder or melt [1]. These are then hot-compacted to structurally consolidated mono-composites under pressure and temperature in a pressing process. For the most part, the fiber composite concept relies upon the embedding of stretched endless fibers or tapes made of PP into a chemically identical matrix. 

In order to obtain good composite properties (interlaminary adhesion), a balanced relation between the selective melting of the textiles for the generation of a sufficient melt amount and the preservation of high macromolecular orientations must be taken into account. By adding an identical thermoplastic matrix material while the material is in a film, powder or melt state, the melt flow and the associated fiber impregnation can be supported and partly improved [6,53,54]. 

Chemical oxidation can also be used to produce conductive powders (e.g. polypyrrole) with a particle size of about 0.1 pm and conductivities of up to 10 S cm, which can be incorporated as fillers in thermoplastics. These materials can serve as chip carriers. 

Rotational molding. A thermoplastic powder is used in this method to which glass reinforcements in the form of chopped strands are added. The resin powder and glass reinforcement are charged into a split hollow mold, heated, and biaxially rotated. After the material has fused, the mold is cooled, opened, and the part removed. 

Similar to 3DP, SLS allows for processing of a wide range of materials, induding thermoplastic polymers and polymer-based composites, metals, and ceramics (Figure 20). Necessary requirements for a powder material to be processed by SLS are a suitable particle size distribution, powder flow-ability, suffldent adsorption of thermal energy, and a softening temperature that fits into the process window of the respective SLS equipment. ... 

Nunes, J. P., Silva, J. F., Marques, A. T., Crainic, R, Cabral-Fonseca, S., Production of Powder Coated Towpregs and Composites, Journal of Thermoplastic Composite Materials, 16 (3), (2003). 

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