The study examines the geometric behavior of corrosion-resistant steel components manufactured using the DMLS (Direct Metal Laser Sintering) process after various post-treatment methods. Full-surface 3D optical scanning was used to evaluate geometric deviations before and after three different treatments: stress relief heat treatment, immediate base plate removal, and natural aging. The results showed that heat treatment amplified the distortions caused by existing residual stresses, with elliptical deformation nearly doubling (i.e., deteriorating by approximately 200 %). Immediate removal resulted in asymmetrical, teardrop-shaped distortion that exceeded the ±0.1 mm tolerance limit. Natural aging effectively stabilized the geometry, with circularity deviation remaining within the ±0.1 mm limit. The results highlight the critical role of thermal management and post-processing in ensuring the dimensional accuracy of DMLS parts. The research demonstrates the advantages of full-surface, high-precision optical metrology in the detailed analysis of shape changes occurring during additive manufacturing, with the maximum permissible error of the measuring system limited to 0.01 mm in our measurements.

Residual stresses are one of the main challenges in metal additive manufacturing, particularly in direct metal laser sintering (DMLS). These stresses often lead to deformation once parts are removed from the build plate. In this study, we investigated the causal relationship between internal stresses and deformation behavior using a specially designed twin-cantilever geometry. This setup allowed parallel evaluation of different stress-relief treatments on a single component while minimizing cross-effects. High-precision optical 3D scanning was used to measure full-surface deformations before and after support removal and stress-relief heat treatment. The 1.2709 maraging steel (X3NiCoMoTi18-9-5) specimens were produced using a DMLS process with standard parameters, and stress-relief annealing was performed at 600 °C for 24 h. Results show that the heat treatment significantly reduced distortion on the supported side of the parts, with changes under 5%, while unsupported regions showed increased deformation, exceeding 60% in some cases. This indicates that internal stresses remain largely intact during heating and can further distort softened material if not mechanically constrained. The study confirms the critical role of constraint during heat treatment and demonstrates that optical metrology offers a reliable method to evaluate deformation trends. The results provide important insights into stress management strategies for DMLS parts and highlight the limitations of thermal relief in unconstrained geometries.

Direct Metal Laser Sintering (DMLS) technology is gaining ground in the automotive industry, especially in areas where a high strength-to-weight ratio is of paramount importance, such as racing cars and limited production supercars. It has the advantage of being able to create complex, weight-reduced components. In this research, we present a scanning electron microscopy study of a powder feedstock of a given particle size. The state of the new feedstock and the effect of cyclic reuse are investigated and the changes are analysed. DMLS technology enables virtually waste-free production, as the powder can be reused after sieving, with the exception of the supports used for undercuts. The aim is to investigate whether the particles tend to agglomerate and thus form larger irregular clusters. It is well known in the literature that clusters adversely affect powder fluidity, spreadability and laser energy absorption, suggesting that the quality of the powder is a fundamental determinant of the properties of the final product. Clusters should be identified and investigated from both a scientific and a technological point of view. The investigated powder material is Oerlikon MetcoAdd 17-4PH-A, a martensitic stainless steel feedstock produced by gas atomization.

Additive manufacturing is becoming increasingly popular in motorsports and the world of limited edition supercars, as it can be used to produce parts with an excellent strength-to-weight ratio. 3D metal printing is one of the newest and fastest-growing branches of additive manufacturing technologies. One of the biggest challenges of this technology is the formation of residual stresses, especially in the case of direct metal laser sintering (DMLS). These internal stresses often cause deformations and warping, especially when the parts are removed from the base plate. In this study, we examined a twin cantilever geometry using an optical scanner. The optical scanner allows for high-precision examination of the entire surface, so we can evaluate the entire piece based on millions of points rather than just a few points. This allows us to evaluate the test piece more accurately. This also allows us to evaluate areas that cannot be analyzed using traditional point-based testing. We demonstrate the advantages of digital point-based measurement technology, which not only focuses on the accurate measurement of changes, but also compares the differences between the changes in multiple components, providing further evaluation possibilities. The study confirms the advantages of optical measurement technology in complex deformation tests and demonstrates the in-depth analysis possibilities offered by detailed surface scanning.