Saturday, 5 May 2012

Exciting times in 3D printing

3D printers that build up models by setting UV curable resins with lasers, layer by layer are one of the oldest types of 3D printer, however, they are still one of the most expensive. Several years ago someone hit upon the idea of using projectors to cure resin selectively, the paper I read used a UV light source and an industrial LCD. LCDs however don't really like UV very much at least bog standard ones filter a lot of it.

Texas instruments then came up with their DLP micro mirror projectors which image using an array of tiny mirrors. These too can be affected by UV but at least do pass it. Several companies now produce printers based on this technology.

The printers are simple in principle, a light source with a decent UV content (a projector bulb has plenty) and a DLP projector and then some means of moving a build platform up and down. You have two options when building, you can build from the top of a vat of resin and move the build platform down or you can build through the transparent bottom of a vat and move the built platform upwards. The latter method is simpler in many ways but you can have problems with your part sticking to the vat bottom either through adhesion or the vacuum forces created as the part is lifted from the vat bottom (try lifting a piece of glass off another directly upwards).

A few amateurs have had a go at making this type of printer and have had good success, this one in particular is really amazing and has already produced excellent results. He hopes to make a low cost kit in the near future, check out his Facebook page for more info:

A render of the production model, the real thing looks as good (or it will with once anodized)

The prototype machine making a lovely model of the Eiffel tower.

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