Shot Peening
Shot Peening at 3Faktur
3Faktur uses a shot peening booth of type SMG 50 that has been optimized for this purpose by “MHG Strahlkabinen”. The special equipment of the booth is necessary because the process involves a high static charge of the shot peened material, which is reduced by the processing booth.
Shot peening is applied to all dyed components at 3Faktur. It is not necessary to order this service separately.
Functionality
In shot peening, the 3D printed and dyed parts are blasted with plastic beads. The relatively large spheres have a high kinetic energy, thus a locally high temperature is generated upon impact. As a result, the surface is compacted (“pressed tight”) and the porosity is reduced.
Shot peening is to be distinguished from normal cleaning blasting, in which all parts in the production process are blasted and freed from residual powder. Glass beads with a much smaller grain size are used, which reliably clean but do not compact the surfaces.
3Faktur uses the Mutli Jet Fusion process for additive manufacturing of plastic parts. For technical reasons, this powder-based technology produces relatively rough (Ra 7 – 10 µm) as well as slightly porous surfaces, which can be refined with shot peening.
Shot peening is therefore a second, subsequent blasting process that is only used for dyed parts.
Applications
Shot peening is used for visible parts. We therefore use this process as standard for all dyed components.
The decision whether to use shot peening or vapor smoothening depends on the desired effect and the geometry of the part:
- Chemical (vapor) smoothing: more gloss, lower roughness, suitable especially for small to medium sized and / or irregular components
- Shot peening: usually higher homogeneity, suitable especially for large and/or flat surfaces
Special Features
The parts are blasted in a specially equipped blast cabinet. Round plastic beads are used as the blasting material, which, in contrast to the ceramic balls frequently used in the metal sector, have significantly lower wear.
The impact of the beads on the parts generates a high temperature which deforms and hardens the surface structure. Depending on the geometry, the components are shot peened by hand (e.g. large or filigree components) or semi-automatically in a processing drum.
Employee in front of shot peening specialized blast cabinet
Manual processing of components
Automated processing in the drum
FAQ Shot Peening
How can I order Shot Peening as a service from 3Faktur?
A separate order is not necessary. All dyeed parts at 3Faktur also undergo shot peening as part of our standard process. This is a special service provided by 3Faktur, which you can see and feel when comparing components from many other manufacturers.
Background: components manufactured additively in the Multi Jet Fusion process are gray after the production process. Dyeing makes sense if the components are visible parts. Since shot peening significantly improves the properties for visible parts (better homogeneity in color and structure, scratch resistance, pleasant feel), we decided to integrate this useful addition as a production standard in the coloring process.
What are the costs for shot peening?
The costs are included in the surcharge for dyeing. Depending on the number of pieces and the size of the component, they range from cents (small components, high quantities) to a single-digit EUR amount for the Black Coloring + Shot Peening process.
Does Shot Peening affect the accuracy?
Normally no, since the effects are only superficial and on a very small scale (a few µm). In the case of geometries at risk of warpage (large-area, flat geometries), the process can increase warpage due to the heat generated during machining.
Does shot peening have any effect on the mechanical material properties?
No, unlike in the processing of metals, where such effects occur, there is no evidence of such an effect in the machining of 3D-printed polyamide components.
Does edge rounding take place during shot peening?
No, unlike abrasive processes (e.g. vibratory finishing) or chemical smoothing, edge rounding takes place on a microscopic scale at most.
Can shot peening also be added to gray components?
Gray components are not suitable for use as visible parts even when shot peening is used. The processing method does not add any significant value to gray components and cannot be ordered in combination without dyeing.
If the effect of reduced porosity is desired for gray components, chemical smoothing is preferable.