Composite models and moulds

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United Composites offers for a wide variety of production techniques several types of mould and models. Some of the production techniques UC uses are;

Hand lay-up
Vacuum injection (VI RTM)
Resin Transfer Moulding (RTM pressure injection)
Several compression moulding techniques (cold pres, warm pres, compression moulding of prepregs)
Prepreg techniques (vacuum bagging and cure in oven / autoclave)

MODEL MATERIALS TOP

The selection of mould materials depends mainly on required the operating temperature, pressure and dimensional accuracy of the tooling (mould) which has to be made. We make a distinction between two types of models, the hand made models and the CNC machined (5 axes milling) models. The applied mould materials can be;

MDF/WOOD
for cheaper models were the mould are laminated at room temperature and dimensional accuracy of lesser importance (approx. +/- 0,5 up to +/-1mm). (MDF/wood models are also used for sandformes used by casting of metal moulds). In general this type of models are painting in two component paint systems.
TOOL BLOCK (hard polyurethane foam)
This type of model materials are more expensive, and are used for moulds which are laminated and initially cured at higher temperatures and/or pressure, are dimensional more accurate (<+/- 0,5 mm) and are more temperature stable (up to approx. 80 ºC). Tool block type of model materials can be bought in several densities and are generally CNC milled. Milled models are in general painted with and temperature resistant two component paint system like PU based or special epoxy based paints.

MOULD MATERIALS TOP

UC uses several mould materials. The selection of these materials depends mainly on the number of part to be made, the processing temperatures and pressures, the production rate, chemical resistance and demanded accuracy. FRP materials are:

Polyester laminate or polyester concrete
(made by hand lay-up or vacuum injection)
Epoxy laminate or epoxy concrete
Tooling prepregs

The above mentioned materials are commonly reinforced by glass and/or carbon fibres, or in case of casting filled with quarts sand. Gel coats are normally used to improve the surface quality and to improve release of the product. It is possible when gel coats are used to add all sorts of surface structures to the mould. Gel coats can be based on polyester, vinlyester or epoxy.

Other type of mould materials are; (Mainly used when a higher lifetime, and/or accuracy, and/or process parameters are required.)

Aluminium (caste aluminium, milled aluminium, or sheet work)
Steel (caste steel, milled tooling steel, sheet work)
Ceramics (for extreme high process temperatures)

MOULD TYPES TOP

As already mentioned, different type of production techniques are used by UC, which different type of tooling is needed. We make a distinction of two types, the open mould types and the closed mould types. Some examples are;

Open techniques

Hand lay-up mould (one side mould)
Casting moulds (consists of one or more mould parts and is a semi open technique).

Closed techniques

RTM techniques
- Vacuum infusion moulds( one side mould vacuum bagged with foil or silicon blankets)
- Vacuum injection moulds (two sided moulds).
- Pressure injection moulds (two side moulds)
Compression moulding tooling
Prepreg tooling (moulds commonly made with tooling prepregs and used in oven and/or autoclave type of production processes)

Mould can be equipped with extra heating. Used methods are;

Water heating/cooling
Oil heating/cooling (integration of heating/cooling ducts in mould)
Electrical heating by spirals or heating elements.
Air circulation heating
Infra red heating (indirect)

CAD/CAM TOP

Nowadays 3D CAD design (Pro Engineer, Catia, Solid Works, Mech. desktop etc.) is more and more used in all layers of the industry. By this virtual models are created in the computer and the actual model is not really needed any more. With the introduction of CAM software (Computer Aided Manufacturing) which is nowadays also integrated within some of the above mentioned CAD systems, milling programs can be made and directly send to 5 axes or more milling machines which mill the CAD designed mould directly from aluminium or steel. The step of actually making a model is skipped and replaced by a computer model.

UC works together with highly advanced toolmakers who are equipped with state of the art 5 axis portal milling machines. These machines are capable of milling large size, highly accurate (< +/- 0,5 mm) metal tooling which are double curved.

More and more our customers also decide to have the models made by CNC milling. This due to the higher accuracy, quick production time, and general increased quality.

The information we need to design and produce the tooling is simply 3D drawings on IGES or STEP format.

TOP

Some examples

MODELS

MDF model of ceiling element / produced by Groothuis Modelmakerij i.o. UC