The primary objective of the RPDG is to
offer a comprehensive range of services all geared towards considerably
quickening the time taken to develop a product, from the initial design
stage through to completion and mass production.
Design software can provide
photo-realistic images ideal for the early stages of product development
and marketing purposes, whilst a physical prototype model can speed up
the approval process.
A variety of techniques and services are
available for the transfer of RPD technologies to Companies, including:-
Computer Aided Design and
Manufacturing (CAD/CAM) - Using modern draughting technology and
design software, a 3D image of a product or component can be produced on
the flat screen.
Stereolithography (SLA) produces
parts by a layer manufacturing process directly from CAD data. It is
currently the most beneficial method of quickly producing prototypes.
These benefits arise from the short lead-times, accuracy and cost of the
parts. The uses to which parts may be put are huge.
Selective Laser Sintering (SLS) is
a process of sintering together layers of powder (eg. nylon or glass
filled nylon) into a 3d model with a laser. A very commonly used RP
technique, developed by DTM and EOS. This method of prototyping offers
the highest level of functionality combined with speed that is currently
available. Parts can be produced in Nylon or Glass filled Nylon directly
from the machine, which, whilst not correlating with the properties of
their injection moulded equivalents, surpass other materials available.
The option to build parts in Polystyrene allows an additional fast track
route to metal castings.
Thermojet Modelling builds 3D
models from STL files in a wax material. These models can be used to
communicate design ideas, or as a sacrificial pattern in the investment
casting process. When used in conjunction with investment casting,
Thermojet offers a fast and accurate method of producing a functional
cast metal part, without the need for costly wax tool manufacture.
Vacuum Casting uses silicone
tooling and polyurethane resins and is the most widely used secondary
process in rapid prototyping. Applications are quick, low cost multiple
reproductions of master models; target material simulation; fine detail
and texture reproduction; fit, form and function testing; Marketing and
Publicity; photoshoots; low volume manufacture.
Z-Corp Model-making -
the Z Corp machine has one of the highest build rates of any RP machine
on the market today. Figures in excess of 450mm per hour are possible on
a component 200mm x 100 mm. Parts are easily built within a few hours or
perhaps a morning. Parts are built from a fine powder which also acts as
a support during construction. This alleviates the need to design
supports and means that at completion of a build, the unused powder can
be dusted away to reveal the component. All that remains is to
infiltrate the part with a chosen material, usually wax or superglue,
and dress if required to remove evidence of layering.
Laminated Object Manufacturing (LOM)
- profiles of object cross sections are cut from butcher paper using a
laser. The paper is unwound from a feed roll onto the stack and bonded
to the previous layer using a heated roller. The process is marketed
commercially by Helisys who have currently ceased trading.
Injection Moulding is the process
of injecting molten thermoplastic polymer into a cavity, in a hardened
steel mould tool, which opens on a split line (following rapid cooling)
to reveal a plastic moulding. Typically this process is used to produce
plastic mouldings where the relatively high tooling cost can be
justified by low unit costs and tolerances which cannot be achieved by
other moulding processes.
Rapid Tooling techniques - Through
the use of high speed milling (HSM), electro discharge machining (EDM)
and the laser machining facility, core and cavities can be produced in a
variety of materials. General practice would see the use of aluminium or
steel (P20) for the production of moulding tools, with other materials
being used as appropriate for master patterns or models.
Finishing - Rapid Prototyping
technologies utilise layer based construction techniques which, whilst
offering significant benefits in terms of build speed, have the
disadvantage that the surface finish of the component is stepped. Whilst
the material properties of sintered components result in high levels of
functionality, from the aesthetic perspective they frequently require
hand dressing and texturing. Varying grades of finish can be achieved.
Other services offered by the group
include:-
- High Speed Machining
- Laser Engraving· Investment Casting
- Sand Casting
- Direct Metal Laser Sintering of Tool
Inserts
- Manufacturing
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