Knight Fire and Security Products Ltd
Unit 84 Seawall Rd Ind Est
We use a wide variety of rapid prototyping methods to produce mechanical components which are suitable for the job in hand. Some of these we can do in-house and some we contract out to suppliers we know to be quick and reliable.
This process uses a heated nozzle to produce a continuous fine plastic filament. The nozzle can be moved horizontally and vertically and is used to build up the model one layer at a time. Our in house Dimension Elite 3D printer produces models in ABS of almost any colour (not clear) directly from the CAD model. It is ideal for producing initial prototypes and space models, and can also be used for low volume production.
The SLA process uses a vat of liquid UV-curable photopolymer resin with a build platform that starts at the surface of the vat. A UV laser directed at the liquid surface is used to solidify the resin where required on the platform surface. The platform moves down and the laser is used to build up the next layer on top of the first.
SLS uses a powdered material in a similar way to SLA. Here a high power laser is used to melt the material, fusing the fine particles together. The build platform moves down, another thin layer of powder is added and the next layer is built on top of the first. SLS can work with a wider variety of materials than SLA, since it only requires a fine powder as the raw material, and a laser of sufficient power to fuse the particles together.
A silicone mould is used to create urethane moulded parts. The mould is created by casting silicone around a master part, typically made as an SLA. Two-part urethane resin is poured into the silicone mould and allowed to set. This process is useful for low volume manufacturing and produces parts which are more robust than similar FDM/SLA/SLS parts made by layering, and has good surface finish.
Our in-house CNC machining centre is ideally suited to making rugged aluminium components. Starting from a solid billet, material is machined away to leave the exact shape required. Although this process can be expensive, it may work out to be cheaper than alternatives such as precision casting, particularly for small quantities.
Although not a rapid prototyping method, injection moulding is often the target manufacturing process. Molten plastic is injected under high pressure into an aluminium or steel mould to form the required part. Setup costs can be high due to the need to produce the moulding tool, and lead time is normally many weeks. But the unit cost is very low, the parts can be made using many different types of plastic, and the process is fast and repeatable.
The surface finish for many rapid prototyping processes is not representative of normal manufacturing methods such as injection moulding due to the layering process. Where appearance is important, for example in a customer demonstration or trade show, or where a silicone mould is being made from a master part, a model shop is used to smooth the surface to achieve a fine finish. Often this can be painted as well to look like the final product.