Components made of powder and laser light

Article of 30 November 2018 

Laserschmelzen

Create new components layer by layer with a laser instead of forging or casting them – a trend that is becoming ever more common in the industry. For a long time, so-called additive manufacturing was mainly used for the production of prototypes. For the first time, Festo is now manufacturing a series component made of aluminium.

Powder trickles in waves onto a plate until a uniform, continuous layer is formed. From above, a bright laser shines down and melts it at certain points so that it joins to form a unit. More powder is then added and the process begins anew. This is what it looks like when a new component is produced in additive manufacturing. The process has been used in industry since the 1980s, originally only with plastics. Today other materials, such as aluminium, are also used.

Good preparation is the name of the game

The starting point for each component is a 3D CAD design which the customer or designer creates on the computer. Before production begins, the CAD model is virtually aligned and placed in the installation space of the additive manufacturing system (3D printer). The production department checks which position best fits the geometry of the component.

The precise configuration in the installation space is particularly important when metal is used as the material. With this material, support structures are needed to prevent it from warping – for example by folding up the sides. These supporting structures must be easy to remove mechanically after the additive production process. For this reason, it makes sense, especially for series components, to agree on the component orientation prior to design.

A printed component made of aluminium in the installation space: the honeycomb support structures and the substrate plate on which the component is welded are manually removed after printing
A printed component made of aluminium in the installation space: the honeycomb support structures and the substrate plate on which the component is welded are manually removed after printing

Layer by layer the component is finished

Once the correct position has been found, the 3D printer can begin work. An aluminium plate – the so-called substrate plate – is inserted into the installation space, screwed tight and heated to about 170 degrees. A coater then travels forwards and backwards over the plate and applies the aluminium powder, which the laser melts at the points specified by the CAD model. One layer is roughly 50 µm thick – comparable to a human hair.

At the end of the manufacturing process, the entire installation space is filled with powder. Hidden inside are the finished components. The system operator suctions off the loose powder with a vacuum suction cup. It is fed back into a powder container and can be reused for the next production run. The operator then removes the substrate plate together with the components. In the next steps, the components are cleaned, separated from the substrate plate, the supporting structures removed and, if necessary, important areas reworked, for example by CNC milling – and the new component is ready.

The 3D printer used to produce aluminium components
The 3D printer used to produce aluminium components

First series component at Festo

The air tubes for the energy throughfeed in the DRRD swing-piston drive from Festo have recently been manufactured for the first time as a series component using additive aluminium. The semi-rotary drive is mainly used for gripping tasks that are connected with a rotation – for example when a chocolate is gripped by a conveyor and rotated into its packaging on another conveyor. The energy throughfeed ensures that the air ducts and other cables run inside the semi-rotary drive. This is so they do not wrap themselves around the outside of the drive and do not obstruct it when turning. Further components with the additive manufacturing process are planned for the future.

The air tube for the energy throughfeed in the DRRD swing-piston drive is the first series component that Festo is producing by additive manufacturing with aluminium
The air tube for the energy throughfeed in the DRRD swing-piston drive is the first series component that Festo is producing by additive manufacturing with aluminium

Watch the 3D printer at work here: