Procedia CIRP最新文献

Industrial manufacturing is undergoing a biological transformation, which has become a growing part of current research in production engineering. The technologies involved help to translate innovative approaches into existing or novel medical devices. Currently, however, even the most advanced blood contacting medical devices fail to be sufficiently inert to blood, thus causing acute effects – coagulation, inflammation, embolism, stroke – as well as chronic ones – inflammation and chronic use of anticoagulants. We present the marriage of advanced molecular science, nanotechnology and advanced production engineering to improve the hemocompatibility of hemodynamic systems, such as artificial hearts. Our consortium has joined forces to develop nature-inspired coating systems that improve hemocompatibility, prohibit adhesion of bacteria and minimize the growth of dangerous large thrombi. We achieve this by (1) concealing the presence of the titanium surface, thereby minimizing the activation of inflammatory and coagulatory reactions, (2) locally inactivating those molecules that cause uncontrolled coagulation, (3) directing the blood to use its own fibrinolytic system to digest the clot and (4) introducing micro surface patterns that interfere with the flow near the surface generating shear, which in turn prohibits dangerous clots from growing. In vitro tests demonstrate considerable improvement in hemocompatibility.

Bone drilling poses intricate challenges due to its high hardness, strength, and anisotropic composite structure. In the dynamic field of orthopedics, advancing surgical drilling techniques is imperative for optimizing precision and implant stability. As drilling methods have progressed from conventional to robot-assisted machining, some new possibilities are now appearing. While orbital drilling has been pivotal in aerospace for reduced forces and superior hole quality, its application in bone drilling remains unexplored. This study pioneers the introduction of orbital drilling for bone machining, aiming to unveil its potential to improve processing quality. Experimental investigations were conducted on cortical femur bone to evaluate its mechanical behavior and the geometry of the holes, encompassing parameters such as hole aperture, roundness, cylindricity and delamination. Employing full factorial statistical analysis, the study systematically elucidates the influence of cutting speed and feed rate on hole quality. Results reveal the potential of orbital drilling in mitigating its defaults and could significantly contribute to improving surgical outcomes in orthopedic procedures.

For decades, fossil-based materials have formed the basis of an almost endless range of technical products. Through variable chemical composition and several additives, especially plastics can have a wide range of properties, which form the basis for the diversity of plastic-based products. While this variability enables many sustainability strategies, such as lightweighting, it is also impeding a fully circular economy. Therefore, in recent years, a number of new raw materials have been developed, but they can only cover a very limited part of the wide range of properties of fossil-based plastics. Another promising class of materials are composites based on fungal mycelium.

However, these are mainly limited to the consumer sector, e.g. vegan leather, where there is smaller demand for durability, functionality etc. The step from consumer to engineering materials require the production (or growth) process to be reproducible within the necessary quality requirements. Cyber-physical production systems have the potential to realise necessary technical qualities despite e.g. quality fluctuations of the raw material and production processes that are susceptible to interference. For this reason, this paper analyses the state of the art in production of mycelium based composites, shows the existing gaps and draws a vision to close these gaps.

Biointelligent manufacturing represents one of the most promising innovation paths towards a sustainable restructuring of industrial production. In doing so, it assumes significantly changing framework conditions for the production of a wide variety of goods. A recurring element is the decentralization of value chain design, i.e. an increasing shift of the focus of value creation to the customer. While the concept of decentralization has been discussed in the context of systems and organization theory, green supply chain and life cycle management for quite some time, recent studies suggest that especially biointelligent manufacturing systems might represent a promising technological opportunity to truly realize this goal. However, up to now the concept appears somewhat vague, as neither the validity of the assumption of increasing decentralization nor the extent to which a reduction of supply chain length results in an improvement of environmental impact is resolved. This paper is intended to provide a foundation for the advancement of the research area by analyzing the state of knowledge and uncovering logical misconceptions. Although the findings indicate a clear technical decentralization potential of biointelligent manufacturing by various examples, a comprehensive dissemination as small-scale production units in industrial practice remains unlikely due to prevailing organizational and socio-political barriers.

Recent innovations in Drug-Eluting Stents (DES) technology have led to the development of new stents with further reduction in strut width, the ultrathin DES, with struts thinner than 70 µm. Ultrathin DES may further improve the efficacy and safety profile of Percutaneous Coronary Intervention (PCI) by reducing the risk of target-lesion and target-vessel failures compared to the current-generation DES. However, the ultrathin DES metallic platform still presents some associated problems, such as biofilm formation, infection, and migration, all related to the cellular response.

The present work aims to produce an ultrathin permanent polymeric platform for a new generation of polymeric drug-eluting stents (PDES). In this work, the cellular response was compared with the traditional stainless steel (SS316L) and polycaprolactone (PCL) to determine whether these polymers could address this challenge. An innovative method of tubular 3D micro stereolithography tubular (ST3DT) was used. Different PDES platforms were fabricated with different polymeric materials (based on polyurethane and urethane dimethacrylate). Subsequently, HFL1 fibroblasts were seeded on the PDES, PCL and SS316L for 3 days. The findings from the assays of cell biocompatibility and proliferation (75%PCL), coupled with the successful fabrication of stent struts below 70 µm using the Surgical Guide resin and the ST3DT method, suggest that resin is a promising candidate for a PDES.

Cellulose-based biocomposites, such as Cottonid, are a promising class of materials to improve the carbon footprint of products during their service life. Cottonid has high technological potential due to its physical and mechanical similarities to engineering plastics and light metals. To replace traditional metallic materials in industry, cellulose-based semi-finished products need to be formed and cut. In particular, blanking is the most cost-effective and industrially common cutting method for metals. However, this study investigates the influence of various blanking process parameters on the quality and the fatigue strength of the resulting cutting edges of Cottonid. The presented results give insights on how the relationships between process parameters during cutting and resulting material properties known from conventional materials can be transferred to cellulose-based biocomposites like Cottonid. The relative clearance was varied between 4 and 10% and the cutting velocity between 0.05 and 10 m/s. It was evident that slower velocities and smaller clearances resulted in visibly better cutting edges. In order to relate this effect to the mechanical performance of Cottonid, new 3-point bend specimens were taken from the blanked strips for fatigue testing. It was found that the fatigue strength was significantly affected by the velocity and clearance. Further, similar to metallic materials, clean-cut (smooth area) and a fractured zone can be clearly distinguished. A good cutting edge quality results in a higher resistance of the Cottonid component against crack initiation at process-induced defects. The knowledge gained may enable an efficient cutting process for cellulose-based materials with higher fatigue strength in the future.

This paper presents a flexible digital twin framework tailored for the biomanufacturing of advanced therapeutic medicinal products (ATMPs), particularly focusing on chimeric antigen receptor T cell (CAR T cell) therapy. CAR T cell therapies face significant challenges in the management of their personalized and complex biomanufacturing processes. To tackle these issues, we propose a novel software framework for a digital twin system aimed at digitalizing, monitoring, and managing the physical production processes. The framework has a hierarchical architecture that methodically organizes production into distinct abstraction levels: processes, tasks and skills, and microservices. This layered architecture simplifies the modeling of complex biomanufacturing production and ensures that each component can be individually updated without disrupting the overall system. Furthermore, the digital twin framework integrates both manual and automated operations within a unified system, accommodating varied requirements of diverse tasks in production. The framework’s flexibility enables easier adaptation to dynamic technological advancements and allows for swift modifications in production processes, making it a sustainable and resilient digitalization infrastructure for ATMP manufacturing.

Electromobility applications require several welded connections using demanding materials often in dissimilar combinations. Copper, aluminium, or steel alloys are laser welded for energy storage and traction related components. On the one hand, high power fiber laser sources provide in-source beam shaping solutions able to modify the irradiance profile towards ring-shaped beams. On the other hand, research focused on the effect of the beam shapes on the melting mechanisms and process quality is still in progress. This work studies the effect of different beam profiles on AISI301LN, AA6082 and pure Cu with a 5 kW fiber laser. Linear trends of power over penetration depth as a function of speed confirms the validity of employing the lumped heat capacity model for ring-shaped beams. Moreover, the specific melting fluence is observed to exhibit an exponential decaying trend with the proportion of power allocated in the fiber core, irrespective of tested material.

The porous transport layers (PTL) are an essential compound of proton exchange membrane electrolyzer cells (PEMEC), widely seen as the most promising solution to produce large amounts of hydrogen needed to replace fossil fuels in the near future. To increase the efficiency of the PEMEC, thin titanium sheets with high porosity should be used as the PTL. This study examined the structuring of thin titanium sheets using ultrashort-pulsed laser radiation with an infrared wavelength. Systematic experiments were conducted to investigate the influence of the pulse repetition rate (PRR) on the structure quality. The resulting holes drilled were analyzed using a laser scanning microscope. Preliminary results showed that laser pulses with a duration of 500 femtoseconds allow the production of thin titanium sheets with a porosity of 63 %, which can pave the way toward PEMEC with significantly increased efficiency.

In rail vehicle construction, austenitic stainless steels are used to achieve lightweight design concepts, as the higher specific strength of the material allows the thickness of parts to be reduced. However, when these are welded to create complex structures, increased welding distortion occurs even with low-heat joining processes such as laser beam welding.

In order to reduce distortion, an in situ low transformation temperature (LTT) effect has been achieved using commercially available materials rather than specially manufactured LTT alloys. The LTT effect introduces compressive stresses into the weld seam, which counteract the formation of welding distortion due to tensile stresses. However, in the case of complex structures, several other factors influence the formation of distortion. The influence of the LTT effect and other factors such as tack welding, clamping and cooling conditions were analysed by distortion measurements and a maximum distortion reduction was determined.