Background case
Using laser melting technology-one of the 3D printing technologies-a scientific and industrial cooperation created an internal combustion engine that almost 21% less weight in the "Leichtbau Motor" project. This notable weight reduction impact has drawn a lot of interest, particularly in the aerospace sector where aircraft performance and efficiency depend on light weight design.
technical ideas
By layer by layer material stacking, metal 3D printing technology is an additive manufacturing method turning digital models into physical ones. The basic idea is to produce a 3D model of the intended product using computer-aided design (CAD) software, then slice and decompose the model into several thin layers, producing the printing path for every thin layer. After choosing the suitable 3D printer and materials, move the sliced files to the printer for layer by layer printing and at last finish the object's production.
case examination
Design for weight reduction of crankcase and cylinder head
The crew of the "Leichtbau Motor" project decided to maximise engine cylinder head and crankcase performance. These two aluminium alloy castings have seen notable weight reduction following 3D printing technology remanufacturing.
The covering of the cylinder:
By means of topological optimisation of the cylinder head, the rebuilt cylinder head has lowered weight by 2.3 kg, thus 22% less than the original component.
The section experiencing great mechanical stress has been reinforced in order to guarantee the strength following weight reduction. Double T-beams (IPB) combined with integrated closed drawers produces the ideal weight reduction to stiffness retention ratio.
The innovative cross flow cooling system reduces the temperature in the combustion chamber by up to 40% by using a separate cooling line instead of a big capacity water jacket, therefore lowering the necessary water intake.
Crankscase:
Designs for weight reduction: The rebuilt crankcase weights less 5.1 kg. Designed as a short skirt with an aluminium bed plate, the crankcase substitutes the steel bearing cover with the bed plate, therefore lowering the basic diesel engine main bearing friction.
Open horizontal load structures found in the crankcase's partition are reinforced with cross-ribbed composite materials at suitable places. Extra reinforcement comes from the two light-weight connecting pipes in the vicinity of the balance axis.
Material optimisation is Glass fibre reinforced phenolic resin makes up the side cover of the crankcase, therefore saving roughly 15% of weight.
Improvement of the oil circuit and exhaust pipe
Exhaust pipe: The insulation layer is directly printed using 3D printing technology, therefore accelerating the heat generation in the exhaust gas post-treatment system.
Optimising oil circuits: Both during cold start and regular operation, the better oil circuit offers additional benefits. New wiring (bending instead of sharp deflection) and cross-sectional improvements jointly lower pressure losses in the cylinder head and crankcase by 22%.
Applications of benefits
lightweight design: By means of ideal printing structures and enhanced material qualities, metal 3D printing technology achieves lightweight design of aviation components, thereby greatly boosting the performance and efficiency of aircraft.
As an additive manufacturing technique, metal 3D printing technology essentially prevents the loss of resources, time and other costs in the process of "equal material manufacturing and subtractive manufacturing". Customising personally helps to shorten the creative cycle and increase manufacturing efficiency.
Manufacturing with a complex structure: Metal 3D printing technology can immediately translate CAD models into physical models for aviation components with complicated structures, therefore accomplishing one-to--one exact replication and addressing the challenge of difficult reproduction in conventional manufacturing techniques.
Some aviation components in the aerospace sector have limited service lifetime and need regular maintenance and repair. Rapid component production and exact damage area restoration made possible by metal 3D printing technologies help to save production costs.
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