Rapid Prototyping (RP) - An overview of metal coating
Rapid Prototyping is the automated construction of physical objects by additive engineering, direct from data, using solid freeform fabrication for a wide range of applications. Rapid Prototyping takes virtual designs from computer aided design (CAD) or animation modelling software and transforms them into thin, virtual, horizontal cross-sections and then creates each cross-section in physical space, one after the next until the model is finished. Morganic Metal Solutions partners with Drumlord Limited for quality, turnkey Prototyping solutions.
Rapid Prototype models can be readily encapsulated in metal. At Morganic Metal Solutions we use PURE copper but uniquely, in a NANOCRYSTALLINE form, this has properties more akin to mild steel than to any other form of copper - for example it has spring properties that impart enormous strength to RP models.
Also as the metal is Nett Shape formed it knows no (previous) form other than that in which it grows - in addition the nanocrystalline structure will not allow the part to deform, across a far greater temperature range than the bare RP.
Any thickness can be deposited, we could build a one metre cube if required; but more commonly a thickness of 150 microns is applied to an RP.
It is more accurate to think in terms of growing an identical part on top of the substrate. Where tolerances are critical, it is necessary to under-build the RP by 150 microns (0.15mm) to allow for this. For example, hole diameters need to be enlarged by 300 microns to accommodate 150 microns on each radius.
To think of the process as plating can be very misleading, as the only common factor is electrolysis and this is actually electroforming: the use of electrolysis to make a part by Nett Shape Forming in nanocrystalline metal - NOT merely applying an alternative finish to an existing part.
The application of Morganic Metal Solutions process to Rapid Prototyping can extend to cover virtually every conceivable field of engineering endeavour. Examples include:
- Fully Finished Prototypes: Models of consumer goods (kettles, toasters, food mixers, taps etc) in fully finished form, (polished and chromed for example) for market evaluation
- Wind Tunnel Models: This imparts strength to the RP to allow for comparison with Carbon Fibre Composites
- RF Screening: Nanocrystalline copper can be applied selectively to achieve definitive RF and Electrical Noise screening
- Antennae: Forms of antenna can be grown that defy machining or fabrication. Metal can also be applied selectively to any given pattern
- Vacuum form tooling: Moulds can be produced with hard metal surfaces to impart the desired finish
The addition of a high tolerance wax build Rapid Prototyping has created the prospect of hollow forms in a way that was previously not possible. Making small to moderate volumes of parts with greatly reduced tooling costs is a strong driving force for this market segment, as is the direct fabrication of tooling itself.
A 15 micron build capacity is now available from 3D Systems in a high quality hard engineering wax with exceptional details capability. To create hollow forms these are encapsulated directly, incorporating any required fittings in the build, and the wax then removed. These forms can also be totally hermetically sealed.
Note: Test reports from QMUL (Queen Mary University of London) materials department and proof of the ability to create totally hermetically sealed hollow forms from TWI microjoinings division are available on request. [link to cryogenic section]
Volume production of Complex Metal forms:
In the past this has always required a silicon rubber mould, with all the attendant work and potential loss of details. By using polypropylene, flexible and chemically inert moulds can be produced as a Rapid Prototype, from which identical parts can be repeatedly grown.