3D PRINTING SAVES UP TO 75 % IN SAND CASTING COSTS

How can it be that the same sand core of a turbine wheel costs €3,600 with conventional production methods and only €900 when using 3D printing?

3D printing helps dramatically shorten the production process for molds and cores. Entire steps, including expensive tool costs, among other things, can be eliminated, since only one CAD data set is needed to produce sand molds and cores.

Economical production, from prototypes to small Batches

Producing sand molds and cores without tools makes economical production possible, from individual parts to small batches. Unlike with conventional production methods, there is almost no limit to the complexity of molds and cores in 3D printing. After all, the effort involved in 3D printing does not depend on component complexity.

These factors are particularly apparent in the specific case of manufacturing a sand core for a turbine wheel. With conventional methods, the individual core segments of the turbine blades must be laboriously assembled into a core. With 3D printing, however, the entire turbine core is produced as a single piece. This significantly shortens the entire production process, since the step of assembling the core is eliminated. This means that up to 75% of the costs can be cut in smaller batches.

 

Time is Money

Short delivery times and a high degree of flexibility play a crucial role in meeting a wide range of requirements. But how do we link these two factors reasonably and, most importantly, economically?

It takes only a few days to produce sand molds and cores with the voxeljet 3D printing process. This saves several weeks of time, compared to conventional production methods. It also increases flexibility in many respects. First of all, there is no need to worry about undercuts or draft angles.

In addition, necessary casting devices such as the deadhead system can be built right into the molding box and printed. Changes to the component can also be made quickly and easily. The goal is to significantly reduce the amount of time and money involved in producing the mold and core and to easily implement complex geometries. 3D printing and conventional manufacturing can also be combined at will.

From printed core to finished cast part

1. 3D Printing Sand molds and cores of any complexity are produced in a layering process. A recoater distributes the particulate material in a very thin layer over the entire build space. A print head then selectively applies binder to the areas where the component will be produced later on. These two steps continue to be repeated until the entire component has been built. The loose particulate material is subsequently removed from the component, which is then post-processed.

2. Blacking Like with classic sand casting, the printed core is also provided with a black wash in the foundry so that it can withstand the high thermal loads.

3. Mounting the core The 3D-printed sand core is subsequently inserted into a conventionally produced mold. Conventional production methods and 3D printing can generally be combined at will.

4. Casting The turbine wheel is now cast. All common alloys can be cast with the 3D-printed molds and/or cores. Different sand granulations can be used to influence the surface quality.

5. Removing the core Like with conventional production methods, 3D printing of sand molds and cores is a lost-mold casting method.

6. Post-processing The component is post-processed after it is removed from the mold. The amount of post-processing work required is reduced by the 3D printing process, since cast parts are already more accurate. This is due to the fact that even complex geometries with undercuts can be printed as a single piece.

3D printingConventional pattern making
QUANTITY5 DAYS21 DAYS 4-6 WEEKS
1898 €410 €3,600 €
53,080 €1,428 €3,684 €
105,490 €2,525 €3,789 €
5022,275 €10,300 €4,628 €

 

Benefits of 3D printing at a glance

  • Saves time: short processing times
  • Saves money: toolless manufacturing
  • High degree of flexibility in terms of batch size, mold design and variants
  • Geometries can have nearly any degree of complexity
  • Complex cores can be produced as a single Piece
  • Size: from small parts to 4,000 x 2,000 x 1,000 mm
  • No storage costs
  • Can be combined with conventional methods at will
  • Spare parts/reverse engineering


voxeljet helps restore power in Ethiopia

A defective turbine wheel meant that a small hospital in Ethiopia was no longer able to maintain its own power supply. The turbine wheel was a single piece, so that producing it conventionally would have been a very expensive and laborious undertaking. The production work would also have taken several months to complete, which was not an option for the hospital. As part of a social project, a number of technology companies were able to restore the power supply within a short period of time. With its 3D printing technology, voxeljet delivered the sand core for the turbine rotor, which was produced as a single piece in just a few days. The power supply could therefore be secured very economically in a short period of time, due to voxeljet's innovative 3D printing technology.