Tool Wear and Milling Characteristics for Hybrid Additive Manufacturing Combining Laser Powder Bed Fusion and In Situ High-Speed Milling

Sommer, David E.; Pape, Dominik; Esen, Cemal; Hellmann, Ralf

doi:10.3390/ma15031236

Cited by 12 publications

(12 citation statements)

References 65 publications

(71 reference statements)

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“…As the processing of IN718 is challenging for machining technologies, the wear mechanisms are much higher, subsequently reducing the maximum tool life compared to the machining of, e.g., maraging steel. 8 The development of the flank wear is similar, as the typical s-shaped progress of the flank wear can be recognised slightly, as Fig. 6 shows.…”

Section: Flank Wear Analysissupporting

confidence: 54%

“…6,7 By virtue of the direct integration, different challenges arise, as the machining within the powder bed affects the performance of the milling cutter, increasing wear characteristics as well as the achievable surface quality. 8 Further, usable for the additive manufacturing of high-performance components, the Ni-superalloy Inconel 718 shows high-strength and temperature resistance in all fields of applications. 9 IN718, generally a hard-to-machine material, challenges the conventional milling technologies, 10,11 as the difficulties get reinforced within hybrid manufacturing, since the milling takes place within the powderbed.…”

Section: Introductionmentioning

confidence: 99%

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Additive manufacturing of Nickel-based superalloy: optimization of surface roughness using integrated high-speed milling

Sommer,

Safi,

Esen

et al. 2024

Laser 3D Manufacturing XI

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Hybrid additive manufacturing techniques capitalise the advantages of additive manufacturing, while, at the same time, circumvent its disadvantages by using in-situ combined subtractive processes. A particularly promising hybrid additive manufacturing approach unites Laser Powder Bed Fusion (LPBF) with in-situ high-speed milling.Here, the advantages of LPBF such as, e.g., design of freedom and choice of a variety of qualified metal powders can be used, shaping complex as well as custom-designed 3D metal parts. The in-situ high-speed milling process, in turn, yields finished surfaces with superior surface roughness and guarantees high geometrical accuracy without the need of any further post processing. While the typical process sequence of this hybrid approach interrupts the LPBF process every 3-10 layers by milling the accessible surface regions of interest, different challenges arise, as this milling process is directly integrated into the powder bed of the LPBF chamber. Wear characteristics of the milling tools increase as a consequence of the surrounding powder, getting reinforced by the elevated temperatures of the thus far printed parts. As being a super-alloy, Inconel 718 is a promising and well-studied candidate for LPBF additive manufacturing, exhibiting high strength and good mechanical properties. However, it is also well known to be a difficult to machine material. This contribution evaluates the process parameters of this innovative hybrid combination with particular focus on optimizing the surface quality. By varying the high-speed milling process parameters infeed, z-pitch, feed rate and rotational velocity of the milling cutter, smooth surfaces with a roughness of R a < 1µm are accomplished. In addition, the wear characteristics of the milling cutter are investigated, characterizing the flank wear as well as the abrasion of the cutters coating. As the flank wear gets increased by the surrounding powder during the milling process, a specific milling path suction is installed, extracting the powder at the surfaces of the components ahead of the milling path. Advantages of this approach are quantified in a comparative study by the analysis of the milling cutters lifetime.

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Section: Flank Wear Analysissupporting

confidence: 54%

Section: Introductionmentioning

confidence: 99%

Additive manufacturing of Nickel-based superalloy: optimization of surface roughness using integrated high-speed milling

Sommer,

Safi,

Esen

et al. 2024

Laser 3D Manufacturing XI

Self Cite

View full text Add to dashboard Cite

show abstract

“…To solve this bottleneck problem, a new type of “hybrid manufacturing” machine has been developed recently by integrating the machining and AM process together [ 29 , 30 ]. The machining of internal surfaces is conducted during the AM process before the surfaces become inaccessible after the AM process is finished ( Figure 21 ) [ 180 ].…”

Section: Hybrid Manufacturing Of Additively Manufactured Ti-6al-4vmentioning

confidence: 99%

“…A significant number of studies have been carried out on the machining of wrought Ti alloys in the past decades. These studies have focused either on the development of specially designed cutting tools and new tool materials [ 23 , 24 ], optimisation of cutting parameters, application of new cooling media and tribology theories [ 25 ], or on the investigation of hybrid machining processes such as thermal-assisted machining (TAM) [ 26 , 27 , 28 , 29 , 30 ]. Since Ti-6Al-4V is the most widely used titanium alloy constituting 50% of total titanium alloy production worldwide, the machining of Ti-6Al-4V has become one of the most widely studied subjects [ 31 , 32 , 33 ].…”

Section: Introductionmentioning

confidence: 99%

The State of the Art in Machining Additively Manufactured Titanium Alloy Ti-6Al-4V

et al. 2023

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Titanium alloys are extensively used in various industries due to their excellent corrosion resistance and outstanding mechanical properties. However, titanium alloys are difficult to machine due to their low thermal conductivity and high chemical reactivity with tool materials. In recent years, there has been increasing interest in the use of titanium components produced by additive manufacturing (AM) for a range of high-value applications in aerospace, biomedical, and automotive industries. The machining of additively manufactured titanium alloys presents additional machining challenges as the alloys exhibit unique properties compared to their wrought counterparts, including increased anisotropy, strength, and hardness. The associated higher cutting forces, higher temperatures, accelerated tool wear, and decreased machinability lead to an expensive and unsustainable machining process. The challenges in machining additively manufactured titanium alloys are not comprehensively documented in the literature, and this paper aims to address this limitation. A review is presented on the machining characteristics of titanium alloys produced by different AM techniques, focusing on the effects of anisotropy, porosity, and post-processing treatment of additively manufactured Ti-6Al-4V, the most commonly used AM titanium alloy. The mechanisms resulting in different machining performance and quality are analysed, including the influence of a hybrid manufacturing approach combining AM with conventional methods. Based on the review of the latest developments, a future outlook for machining additively manufactured titanium alloys is presented.

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“…Due to an in-situ 3-axis milling process, the surface quality is improved as well as the fitting accuracy can keep up with conventional fabrication processes. 18,19 Further, heat treatment processes are used for the post processing of additive manufactured components. Using solution and ageing treatments or hot isostatic pressing, internal voids can be reduced, residual stress can be minimized, and mechanical load behaviour can be modified, respectively improved.…”

Section: Introductionmentioning

confidence: 99%

Optimization of mechanical properties of additive manufactured IN 718 parts combining LPBF and in-situ high-speed milling

Sommer,

Hornung,

Esen

et al. 2024

Laser 3D Manufacturing XI

Self Cite

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Mechanical properties of laser powder bed fusion (LPBF) processed components are sensitively affected by the inferior surface quality, typical for this additive manufacturing technique for metal parts. Using a promising hybrid additive manufacturing approach, combining LPBF and in-situ high-speed milling, the surface quality can be strongly improved within a single process cycle. The milling process is directly integrated into the additive manufacturing chamber, machining the 3D-built surfaces while interrupting the LPBF-process. As a result, surface defects and surface near porosities are greatly reduced.Even though Inconel 718 is difficult to machine, as well as the milling process within the powder bed poses different challenges on this promising approach, a surface roughness of Ra < 1µm is generally achievable, using this particular hybrid additive manufacturing approach.We present a comparative study of the mechanical properties of conventional LPBF-and hybrid-build components with particular focus on the static and dynamic load behaviour, in turn allowing to evaluate the effects of finished surfaces on these mechanical properties. In addition, the influence of different heat treatments on the static load behaviour as well as the fatigue behaviour is investigated. Different heat-treatments are performed, improving the density of the components, and leading to a higher maximum load behaviour. Furthermore, the fatigue behaviour is modified, as the material properties can be changed by virtue of the development of different material phases during the heat treatment processes. Comparing the sole LPBF-and hybrid-built components for the as-built and the different heat-treated states, an improvement of the maximum load capacity as well as of the dynamic load behaviour can be observed for the hybrid-built specimens.

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Tool Wear and Milling Characteristics for Hybrid Additive Manufacturing Combining Laser Powder Bed Fusion and In Situ High-Speed Milling

Cited by 12 publications

References 65 publications

Additive manufacturing of Nickel-based superalloy: optimization of surface roughness using integrated high-speed milling

Additive manufacturing of Nickel-based superalloy: optimization of surface roughness using integrated high-speed milling

The State of the Art in Machining Additively Manufactured Titanium Alloy Ti-6Al-4V

Optimization of mechanical properties of additive manufactured IN 718 parts combining LPBF and in-situ high-speed milling

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