Two-component additive manufacturing process using standard granulates

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  • Arburg’s Freeformer with two discharge units at #Euromold
  • Functional parts made from standard granulates
  • Able to build up water-soluble structures for the first time

Arburg will demonstrate two Freeformers equipped with a three-axis component carrier and two stationary discharge units at the upcoming #Euromold 2014. The exhibits will show how functional components can be additively manufactured from standard granulate based on 3D CAD data. This is the version which has been inquired about by most of the potential customers to date, according to the company.

Two-component application with supporting structure

The second discharge unit can be used for an additional component in order to, for example, produce a part in different colours, with special properties, or as a hard-soft combination.

New for the Freeformer is the option of building up water-soluble structures from a special supporting material. This makes it possible to achieve unusual or complex component geometries. An application of this type will be demonstrated based on the example of a spare part made from ABS, in this case a two-part sliding lock which is used in the Allrounder injection moulding machines. The supporting structures can subsequently be removed in a water bath. As an alternative, a supporting structure can be built up in the same material as the component itself. A thinned out intermediate layer with specifically generated predetermined breaking points enables the supporting structure to simply be broken off mechanically later. This option is preferred for components with free-standing structures and clearly defined edges.

Arburg will present the additive manufacturing of a two-piece sliding lock at the Euromold 2014. Here, the second Freeformer discharge unit is used for the construction of supporting structures, which can be easily removed at a later stage (source: Arburg)

Additive manufacturing process using conventional plastic granulates

With AKF (Arburg Plastic Freeforming), inexpensive, conventional plastic granulates are the base material, one of the advantages compared to other additive manufacturing processes. As with injection moulding, the granulate is first melted in a plasticising cylinder. A stationary discharge unit with a special nozzle then applies the plastic droplets layer-by-layer onto the component carrier using high-frequency piezo technology at a specified duty cycle of 60 to 200 Hertz. Depending on the nozzle used, the diameter of the plastic droplets generated under pressure is between 0.18 and 0.3 millimetres. The moving component carrier is positioned so that each drop is deposited at the precise point calculated in advance. During cooling, the tiny droplets automatically fuse together. The desired three-dimensional component is thus created layer by layer. The construction chamber of the Freeformer offers space for parts with maximum dimensions of 190 x 135 x 250 millimetres.

Automatic data processing

The 3D CAD data for the parts being manufactured (STL files) are processed offline on a PC. A special software generates the necessary manufacturing data via slicing. Once the Freeformer control system has received this data, which determines, e.g. the axis movements, production can begin. Operation is simple, no special programming or processing knowledge is required.

Environmentally and user friendly

One major advantage of working with the Freeformer is that no dust or emissions are generated and no additional infrastructure is therefore necessary. No extraction units or cooling water are required. The system is thus also perfectly suitable for use in an office environment. All that is required are a mains outlet, 3D CAD data and conventional plastic granulate.

Main Picture: Industrial additive manufacturing: with the Freeformer and Arburg Plastic Freeforming (AKF), functional parts can be produced efficiently from standard granulate, without the use of a mould (source: Arburg)

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