Industrialisation has been additive manufacturing's Holy Grail for the entirety of its existence, particularly in metals. Since the inception of the technology known as Selective Laser Melting – invented by their own Director of Scientific and Technology Research, Dr Dieter Schwarze – SLM Solutions has been in the driving seat of that quest.
Over part one of our unique double issue cover story, Ralf Frohwerk, Global Head of Business Development at SLM Solutions discusses the leaps and bounds the technologies have made in establishing themselves as a manufacturing mainstay.
What have been the rate limiting steps that SLM Solutions has had to overcome to move towards industrialising metal additive manufacturing (AM)?
The question of industrialisation is not unique to SLM Solutions, but to all companies in this sector. Metal additive manufacturing is currently moving to this new stage of evolution. The key drivers for SLM Solutions are improved machines with high reliability and high productivity. In general, the objective of metal-based additive manufacturing is to be competitive with traditional manufacturing processes. Besides robust and reliable machines, this is especially possible if the freedom of design, that SLM technology provides, is used.
Laser based metal AM is often labelled as expensive, can you give an example of a customer with good ROI?
Y-connector for a robotic sander.
Depending on the application, additive manufacturing can lead to numerous commercial and technical advantages that allow companies to strengthen their competitive position. A great example of increasing productivity is provided by engineering company Etteplan. Through design adjustments and a nested component orientation, they save 40 percent of the manufacturing costs through 3D printing a Y-connector for a robotic sander. The company maximised the number of nested parts produced in a single build, far exceeding the break- even price with traditional manufacturing. Additionally, a 25% build time reduction was achieved through parameter optimisation as well as functional improvements and a significant weight reduction.
What are the key aspects that lead to low part costs?
Low part costs can primarily be achieved through an innovative and optimised process. SLM Solutions machines combine a multi-laser strategy with up to four 700 W lasers working simultaneously on one build part while overlap areas further increase productivity. Bi-directional recoating further decreases laser off time. Besides part weight, parameters adapted to individual parts, the number of lasers, laser power and selected layer thickness determine productivity. In comparison to an SLM 280, equipped with a single 400 W laser with 30 μm layer thickness, construction time can be reduced up to 80% and costs up to 70% using an SLM 500 quad laser system with 700 W lasers and 90 μm layer thickness.
Another important aspect is the automation of processes, which promotes the achievement of economic goals. The SLM 800 Selective Laser Melting system stands for its automation solutions, where the fully automatic SLM HUB unpacking station integrates numerous functions like an automated transport of build cylinders with dedicated locations for pre- heating and cooling in an inert atmosphere.
The productivity of Selective Laser Melting is, furthermore, dependent on individual applications. To optimally use the advantages of 3D printing, part designs and functions have to be rethought. For example, is it possible to combine entire part groups to an optimised component to reduce assembly effort, or can weight be saved by a consistent lightweight design? How can part properties be improved? This is exactly what Etteplan did and how they achieved a successful AM production.
Read part two inside TCT Magazine issue 28.4 - available for free on Issuu.
ETTEPLAN'S PLAN FOR SUCCESS
120 stacked, nested connectors printed in one process on the SLM 280 by Finnish service bureau 3Dstep.
The stories the mainstream media will write about when it comes to successful AM are often consigned to aviation and medical applications. While those applications do have undoubted appeal, what really excites the industry is the limitless possibilities for AM to make its mark within the countless engineering companies across the globe.
Finnish engineering solutions company Etteplan was tasked with redesigning the Y-connector of a robotic sander‘s dust extraction channel, optimising it for AM. The existing, traditionally manufactured component suffered from high costs, a long supply chain and a large footprint that caused problems in the assembly line. The customer hoped for a new solution optimised for laser powder bed fusion (LPBF) production in aluminium that was significantly lighter than the original with improved airflow characteristics and produced at lower cost.
Etteplan‘s first design for additive manufacturing (DfAM) iteration of the extraction channel smoothed the internal air channels and removed excess material from the design. At this point, process simulation software was used to conduct an orientation optimisation to analyse the effect of print orientation on build time, support volume, needed post-processing effort and predicted deformation/ distortion levels. Two orientations of the extraction channel produced comparable and preferred results in terms of support volume, post- processing and deformations. These orientations resulted in the longest print times for the manufacture of a single component, but conversely they required the minimal area footprint on the build plate, thus when the build plate was fully nested with the components, the per-part print time was actually lower than the other orientation options.
Once oriented on the plate, additional modifications were made to the design to improve printability and eliminate the need for support structures in regions that would be visible to the end-user after assembly in the sander. Print process simulations were used in order to determine where support structures would be required, to ensure that print- direction distortions would not cause collision with the recoater during the printing process, and to check that the final distortion levels of the component were within the requirements.
Eric Shambroom Copyright 2019 Eric Shambroom Photography
SLM Solutions factory environment.
The Etteplan AM cost estimation tool was also utilised during this stage to estimate and compare the costs of various design options with the original, traditionally manufactured part. It was found that for the amount of material and print time needed, it was too expensive to additively manufacture a single part. However, printing 11 parts at once was determined to be the threshold of where the traditionally and additively manufactured components cost approximately the same amount.
Further design changes were made to maximise the number of nested parts produced in a single build. Optimising the design to allow components to be stacked 4-high in the print direction meant that a total of 120 pieces could be printed in one job on an SLM 280 machine, far exceeding the break-even price with traditional manufacturing. Process simulation was again used to estimate the support structures needed and to simulate the print process for a stack of four extraction channels.
An additional 25% build time reduction at service bureau 3Dstep was achieved through parameter consulting and optimisation by SLM Solutions, resulting in additional production cost savings.
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