Express Wire Coil Cladding (EW2C) as an Advanced Technology to Accelerate Additive Manufacturing and Coating

Author(s):  
Marius Gipperich ◽  
Jan Riepe ◽  
Robin Day ◽  
Thomas Bergs

Abstract Metal shafts are indispensable components in mobility, energy and mechanical engineering. In such applications, the shafts need to withstand severe mechanical loads, friction, high temperature or corrosive media. This is why shafts are often completely made of high-performance alloys. From a technical point of view, coating an inexpensive base shaft with a thin layer of high-performance material is mostly sufficient to ensure its functionality. Adding functional parts such as bearing seats by Additive Manufacturing (AM) is an advantageous approach to increase flexibility and material efficiency. Reliable and economic AM processes need to be developed further, and laser-based processes such as wire-based Laser Metal Deposition (LMD-w) offer high potential to accomplish this. Due to their low deposition rate, however, LMD processes are not economically competitive with high-speed subtractive technologies. Motivated by this challenge, we present an alternative approach for laser-based shaft cladding. Instead of adding the filler wire continuously, wire coils are wound and preplaced on the shaft. In a second step, laser processing while rotating the part generates a metallurgical bond between the wire and the substrate. In this study, several solid and flux-cored wires were analyzed regarding their suitability for this two-step coil winding and LMD process. The resulting surface state and the welded joint quality are evaulated. Metallographic cross sections show low porosity and small heat-affected zones. Thanks to its good scalability, this innovative process can help strongly increase the build-up rate compared to classic LMD-w.

2021 ◽  
Author(s):  
Marius Gipperich ◽  
Jan Riepe ◽  
Robin Day ◽  
Thomas Bergs

Abstract Metal shafts are indispensable components in mobility, energy and mechanical engineering. In such applications, the shafts need to withstand severe mechanical loads, friction, high temperature or corrosive media. This is why shafts are often completely made of high-performance alloys. From a technical point of view, coating an inexpensive base shaft with a thin layer of high-performance material is mostly sufficient to ensure its functionality. Adding functional parts such as shoulders or bearing seats by Additive Manufacturing (AM) instead of creating them by subtractive manufacturing is an advantageous approach to increase flexibility and material efficiency. Reliable and economic AM and coating processes need to be developed further, and laser-based processes such as wire-based Laser Metal Deposition (LMD-w) offer high potential to accomplish this. They can generate a stable metallurgical bond between the base material and the cladding or the added feature without excessively heating the work piece. Due to their low build-up rate, however, LMD processes are not economically competitive with high-speed subtractive technologies such as drilling or turning, which are predominately used for shaft production. Motivated by this challenge, we present an alternative approach that increases the deposition rate for laser-based shaft cladding. Instead of adding the filler wire continuously, wire coils are wound and preplaced on the shaft. In a second step, laser processing while rotating the part generates a metallurgical bond between the wire and the substrate. In this study, several solid and flux-cored wires were analyzed regarding their suitability for this two-step coil winding and LMD process. The results from LMD experiments give an overview of the resulting surface state and of the welded joint quality after deposition. Metallographic cross sections show low porosity of the deposited layers and small heat-affected zones in the base shaft. Thanks to its good scalability, this innovative two-step process can help strongly increase the build-up rate compared to classic LMD-w.


Author(s):  
K D Dolbear ◽  
J C Watson

Railway vehicle service speeds are set to increase from the present 300 km/h. These developments are being spearheaded by the French, German, Italian and Japanese railways. It is also clear in other less glamorous areas such as freight and suburban operations, that the trends in vehicle design are going to put severe burdens on the braking technology available today. These initiatives included the advanced suburban bogie for British Railways. While it will be possible to squeeze some further improvements out of conventional products, it has become essential to initiate work on new materials which not only meet the immediate demands but address the requirements of the middle- and long-term. Some proposals such as carbon/carbon may be impractical from a cost point of view on anything other than exotic high-speed vehicles but studies involving ceramic to ceramic interfaces are proving interesting with a real possibility of providing high performance at an economical cost for a large spread of applications. The paper will discuss some of the challenges and opportunities to be grasped and solved.


2021 ◽  
Vol 1161 ◽  
pp. 85-93
Author(s):  
Susanne Hemes ◽  
Waldemar Koch ◽  
Rebar Hama-Saleh ◽  
Irina Sizova ◽  
Frank Meiners ◽  
...  

Ti-6Al-4V is used as a high-performance material in many industries (mainly automotive and aerospace, but also the medical industry) and traditionally produced by hot forging, with subsequent extensive post-processing and machining, leading to a material yield far from 100 % [1]. New production chains, such as additive manufacturing, enable the near net shape production of high-performance parts, however, still with long production cycles and high manufacturing costs, especially for larger parts [2]. Therefore, an efficient and feasible production is often limited to low quantities and/or small pieces. In the present study, we propose a hybrid manufacturing route, combining additive laser metal deposition (powder LMD) on hot forged base components, enhancing material efficiency, but still enabling the production of industrial quantities. Primary investigations on the microstructure and mechanical properties of the material show results similar to conventional hot forged material, but reduce the number of processing steps and increase the material yield.In more detail, the relationship between the primary beta grain size and the secondary alpha phase characteristics was investigated and moreover, related to the cooling history of the material. Furthermore, the influence of the microstructure and phase characteristics on the mechanical properties of the material was analyzed. For the determination of the primary beta grain size, the programming language MATLAB as well as its integrated open-source toolbox MTEX were used, where a GUI has been developed for the reconstruction of the primary beta grain orientations and sizes from recorded EBSD data of the secondary alpha (Ti) phase, using the Burger’s orientation relationship (BOR, [3-7]).


Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.


Author(s):  
Marc H. Peeters ◽  
Max T. Otten

Over the past decades, the combination of energy-dispersive analysis of X-rays and scanning electron microscopy has proved to be a powerful tool for fast and reliable elemental characterization of a large variety of specimens. The technique has evolved rapidly from a purely qualitative characterization method to a reliable quantitative way of analysis. In the last 5 years, an increasing need for automation is observed, whereby energy-dispersive analysers control the beam and stage movement of the scanning electron microscope in order to collect digital X-ray images and perform unattended point analysis over multiple locations.The Philips High-speed Analysis of X-rays system (PHAX-Scan) makes use of the high performance dual-processor structure of the EDAX PV9900 analyser and the databus structure of the Philips series 500 scanning electron microscope to provide a highly automated, user-friendly and extremely fast microanalysis system. The software that runs on the hardware described above was specifically designed to provide the ultimate attainable speed on the system.


Author(s):  
M. T. Postek ◽  
A. E. Vladar

One of the major advancements applied to scanning electron microscopy (SEM) during the past 10 years has been the development and application of digital imaging technology. Advancements in technology, notably the availability of less expensive, high-density memory chips and the development of high speed analog-to-digital converters, mass storage and high performance central processing units have fostered this revolution. Today, most modern SEM instruments have digital electronics as a standard feature. These instruments, generally have 8 bit or 256 gray levels with, at least, 512 × 512 pixel density operating at TV rate. In addition, current slow-scan commercial frame-grabber cards, directly applicable to the SEM, can have upwards of 12-14 bit lateral resolution permitting image acquisition at 4096 × 4096 resolution or greater. The two major categories of SEM systems to which digital technology have been applied are:In the analog SEM system the scan generator is normally operated in an analog manner and the image is displayed in an analog or "slow scan" mode.


Author(s):  
Sai Venkatramana Prasada G.S ◽  
G. Seshikala ◽  
S. Niranjana

Background: This paper presents the comparative study of power dissipation, delay and power delay product (PDP) of different full adders and multiplier designs. Methods: Full adder is the fundamental operation for any processors, DSP architectures and VLSI systems. Here ten different full adder structures were analyzed for their best performance using a Mentor Graphics tool with 180nm technology. Results: From the analysis result high performance full adder is extracted for further higher level designs. 8T full adder exhibits high speed, low power delay and low power delay product and hence it is considered to construct four different multiplier designs, such as Array multiplier, Baugh Wooley multiplier, Braun multiplier and Wallace Tree multiplier. These different structures of multipliers were designed using 8T full adder and simulated using Mentor Graphics tool in a constant W/L aspect ratio. Conclusion: From the analysis, it is concluded that Wallace Tree multiplier is the high speed multiplier but dissipates comparatively high power. Baugh Wooley multiplier dissipates less power but exhibits more time delay and low PDP.


2002 ◽  
Vol 67 (11) ◽  
pp. 1596-1608 ◽  
Author(s):  
Josef Janča

The effect of miniaturization of the separation channel on the performance of thermal field-flow fractionation (TFFF) is substantiated theoretically. The experiments carried out under carefully chosen experimental conditions proved the high performance of the separation of polymers within an extended range of molar masses from relatively low up to ultrahigh-molar-mass (UHMM) samples. The new micro-TFFF allows to achieve high resolution when applying constant field force operation, it makes easy the programming of the temperature drop which is an advantageous operational mode from the point of view of the time of analysis, and it extends considerably the range of perfectly controlled temperature of the cold wall due to a substantial decrease in the heat energy flux compared with standard size channels.


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