Objet helps develop rapid texture prototyping

An Objet Geometries Europe product story

Edited by the Engineeringtalk editorial team Jan 13, 2009

As a post-process, Objet 3D printing technology can add high-quality textures with fine detail to models, so that both the models and their related elements and materials have the same texture.

In many rapid prototyping (RP) applications, surface texture is a major concern of importance.

Not all RP technologies produce finished parts, which makes secondary processes, such as grinding or polishing, possible.

These additional steps add time and cost to prototyping.

As the goal of RP technology is to produce finished models quickly and at a low cost, producing the right surface texture on RP parts is important.

Polyjet Technology can print textures (grains or patterns) and logos on prototype parts, moulds and models exactly as they would be on final production moulds or parts.

If needed, the texture can be limited to specified areas.

However, texture can also be added in a post-process using rapid texture prototyping applications.

Rapid texture prototyping can strengthen thin materials in lightweight structures to improve aero and fluid dynamics, or can be used to fill in layer lines on printed parts to provide a smooth surface, as well as increase the thickness of a wall or a surface without having to make a new part.

Akron Metal Etching specialises in adding textures to different materials and substrates.

Akron developed a post-process method specifically for texturing the surfaces of parts made by Polyjet Technology, called Prototex.

Akron can put just about any texture on parts made from Objet 3D printed models.

With an extensive design library of thousands of patterns and textures including leather grains, geometric patterns and current popular designs, Prototex lets end users achieve just the right look for their finished 3D printed model.

'The advent of rapid texture prototyping technology reduces the effort required for applying texture to printed models,' said Avi Cohen, applications manager of Objet Geometries.

'The goal of textured models is to provide the highest quality mould texturing based on rapid prototype printed models.

'We help to work through the details of texture selection and all the items pertinent to end-user tooling to get parts with just the right textures out of the moulds with ease.' To add texture to Polyjet printed models, first, printed models are thoroughly cleaned and sanded using fine sandpaper.

Second, a coating layer is applied to mask the areas that will not be textured.

After the masking, the texture process is built up onto the parts to the depth of the desired texture.

A special device measures the thickness as it is being built.

In general, a tolerance of +/-0.01mm (0.0005in) is acceptable for texture depths.

With textures of thicknesses from 0.1mm to 0.375mm (0.004 to 0.015in) this step takes a relatively short period of time.

In the next phase, the material is built to the proper thickness.

The red areas are masked off and will remain without texture in the finished parts.

The masking also defines texture changes if multiple textures are being applied.

The ability to add texture to specific areas adds realism to the parts.

The next stage is to apply the texture patterns.

There are several different methods for applying patterns on part surfaces.

After a curing process, the pattern masters are removed from the surface along with the masking materials.

A chemical treatment is used to reveal the pattern.

Finally, after the textures are examined and any necessary touch-up work is completed, the textured areas are lightly coated with an overcoat to seal the texture to the parts.

The parts are then exposed to light to cure the materials.

The texture (grains or patterns) can be applied to both printed Polyjet models and moulds, bridging the gap between rapid tooling and expensive hard tooling.