High Cycle Time Research Articles

Cathodic Arc Deposited CrAlSiN Coatings by Pulsed Current Input

Cathodic arc deposition technique is one of the green processes of the physical vapor deposition (PVD) systems. In this study, Cr and CrAlSi dual metal targets were used in order to synthesize CrAlSiN coatings. By using the cathodic arc pulsed current techniques, three different settings of pulsed current duty cycles were used. The microstructure of the coatings observed by XRD analysis shows all the coatings are B1-Rock salt structure with diffraction peaks of (111) and (200). The pulsed current input as compared to the constant current had presented the higher hardness up HV3771. Corrosion test by polarization method shows the best corrosion resistance of the CrAlSiN was achieved by pulsed current input at high cycle time.

Development of Thermoplastic Composites for Visible Parts in Automotive

In order to reduce CO2 emissions, for the automotive industry, the most promising area of research is lightweight construction. Next to weight reduction, lightweight materials like fiber reinforced thermoplastic composites (FRTC) may also improve mechanical properties of vehicle body parts. FRTCs, so-called organic sheets, have the potential for large scale series production and they can be back moulded due to the thermoplastic matrix. On the other hand high production cycle times and a poor surface quality are limiting their potential. Therefore, ITA’s current research approaches these problems in two ways. Nanomodified materials and a new tool concept for heat pressing are going hand in hand and may lead to the technology’s breakthrough.To reduce the cycle times of the production of FRTCs innovative and modified matrix systems are investigated. The goal of the public founded project “VarioOrgano” is to analyze the potential of these modified yarns and the tool system during the FRTC production. Moreover, the capability of these composites in visible parts in automotive applications is investigated. Therefore, the whole process chain from compounding, to melt spinning, commingling and consolidation with a heat press is investigated.This paper shows the production steps along the process chain to produce these FRTCs with focus on hybrid yarn development and production.

Tailored Inserts Based on Continuous Fibre for Local Bearing Reinforcement of Short Fibre Thermoplastic Components

The injection molding process is an economical process for manufacturing of thermoplastic components. Complex geometries can be realized with high automation and short cycle times. However the mechanical properties of injection-molded parts are not suitable for mechanical demanding components even by adding short or long fibre. As bold connections are used frequently for load transfer, the load introduction area particularly is limited by low bearing strength. The present paper shows the influence of tailored inserts based on continuous fibre on the bolt-loaded hole of injected test specimen.

Effect of flow rate, duty cycle, amplitude, and treatment Time of ultrasonic regimens towards Escherichia coli harbouring lipase

A full factorial design (FFD) approach was conducted to assess the effect of four factors, namely flow rate, duty cycle, amplitude, and treatment time of ultrasonic regimens towards Escherichia coli harbouring lipase. The 22 experiments were performed as the following values with six replicates of centre point: flow rate (0.1, 0.2, and 0.3 L/min), duty cycle (0, 20, and 40 ), amplitude (2, 6, and 10), and treatment time (10, 35, and 60 min). The FFD was employed as preliminary screening in shake flask cultivation to choose the significant factors (P< 0.05) for further optimisation process. In this study, zero duty cycle signified non-sonication of amplitude and no treatment time effect to the E. coli culture. Also, the designated flow rate and amplitude accordingly showed no effect towards the amount of dry cells weight (DCW). DCW1 was found significantly degraded after the exposure of high duty cycle and treatment time as other factors remained constant. Whereas for the lipase activity, no significant difference was observed in any main factors or interactions. Paired samples t-test confirms the result at a p-value of 0.625. This experimental study suggests the direct and continuous approach of sonication caused an adverse effect on the cells culture density.

Continuous versus pulsating flow boiling. Experimental comparison, visualization, and statistical analysis

This experimental study investigates an active method for flow boiling heat transfer enhancement by means of fluid flow pulsation. The hypothesis is that pulsations increase the flow boiling heat transfer by means of better bulk fluid mixing, increased wall wetting, and flow-regime destabilization. The fluid pulsations are introduced by a flow modulating expansion device and are compared with continuous flow by a stepper-motor expansion valve in terms of time-averaged heat transfer coefficient. The cycle time ranges from 1 to 9 s for the pulsations. The time-averaged heat transfer coefficients are reduced from transient measurements immediately downstream of the expansion valves at low vapor qualities. The results show that the pulsations improve the time-averaged heat transfer coefficient by 3.2% on average at low cycle time (1 to 2 s), whereas the pulsations may reduce the time-averaged heat transfer coefficient by as much as 8% at high heat flux (q ⩾ 35 kW/m2) and cycle time (8 s). The latter reduction is attributed to a significant dry-out that occurs when the flow modulating expansion valve is closed. Additionally, the effect of fluid flow pulsations is found to be statistically significant, disregarding the lowest heat flux measurements.

In-mould graining of 3D-shaped parts with micro-structured surfaces

Abstract To make functional surface effects on plastic components usable on an industrial scale, new processes have to be developed. The in-mould graining (IMG) process is a variant of the thermoforming enabling the manufacture of micro-structures. One advantage of the IMG process is that the surface structure is formed to the final shape of the part. Recent investigations show that the forming accuracy of a flat mould can be extended by applying a variothermal mould heating in the IMG process. As high mould temperatures lead to high forming accuracies but also increase the cycle time of the process, a conflict of interests follows. In this paper, it is investigated to what extent high moulding accuracies can be achieved to form three-dimensional parts by using the IMG process extended by a variothermal mould heating. The results show that forming accuracies of micro-scaled structures of &gt;90% can be reached on the bottom and the side walls of a cup-shaped mould. To address the conflict of interests between high moulding accuracy and long cycle times, the influence of the mould temperature is investigated in detail. To analyse the micro-forming behaviour of the processed material, analyses of the rheological behaviour with a rotational rheometer are carried out.

Supply Chain in the Public Procurement Environment: Some Reflections from the Indian Railways

This paper provides analysis of supply chain management framework in the public procurement environment through a case study of the Indian railway. The paper provides some insights about the evolution of supplier relationship management and its impact on key performance indicators. Its also provides an integrative framework for management of public procurement. The paper builds on extensive review of literature and follows a case study methodology. The unit of analysis is the Indian Railway's material management function. Analysis uses data of over a period of five years. The finding highlights that supplier relationships with the Indian railway have been geared around arms-length philosophy. The current symptoms of inefficiencies are reflected in high cycle time, high costs associated with supplier selection process, poor accountability, blurring of responsibility and poor value creation for all the stakeholders. The current procurement mechanisms are not crafted around development of long term strategic partnerships. This study is filling the gaps in literature by presenting the challenges of supply chain management in the public procurement environment. Insights from developing country like India can be applied to other public procurement systems. The paper deals with sensitive issue of public procurement system. The findings would be useful for policy makers in developing mechanisms for instilling insights of business management into the realms of public management. The study is first of a kind to provide a conceptual framework for understanding building blocks of the supply chain management in the public procurement environment.

Turkey: Schulman – masterbatch

This paper provides analysis of supply chain management framework in the public procurement environment through a case study of the Indian railway. The paper provides some insights about the evolution of supplier relationship management and its impact on key performance indicators. Its also provides an integrative framework for management of public procurement. The paper builds on extensive review of literature and follows a case study methodology. The unit of analysis is the Indian Railway's material management function. Analysis uses data of over a period of five years. The finding highlights that supplier relationships with the Indian railway have been geared around arms-length philosophy. The current symptoms of inefficiencies are reflected in high cycle time, high costs associated with supplier selection process, poor accountability, blurring of responsibility and poor value creation for all the stakeholders. The current procurement mechanisms are not crafted around development of long term strategic partnerships. This study is filling the gaps in literature by presenting the challenges of supply chain management in the public procurement environment. Insights from developing country like India can be applied to other public procurement systems. The paper deals with sensitive issue of public procurement system. The findings would be useful for policy makers in developing mechanisms for instilling insights of business management into the realms of public management. The study is first of a kind to provide a conceptual framework for understanding building blocks of the supply chain management in the public procurement environment.

Application of Value Stream Mapping Tool to Reduce Wastes in Bearing Industry

In today’s highly competitive business environment, companies require improvement in Production Lead Times, costs and customer service levels to survive. Because of this, companies have become more customers focused. The result is that companies have been putting in significant effort to improve their efficiency. This paper present the practical application of Value Stream Mapping (VSM) tool implement in a bearing industry. A value stream is an assortment of all actions (value added as well as non-value added) that are required to bring a product through the essential flows, starting with raw material and ending with the customer. For drawing current state value stream mapping, all relevant data has been collected and analyzed. Then analysis of current state map has been done for identifying non-value adding activities, in other words waste and suggestions on how to remove or reduce different wastes. From the results achieved by current VSM, it was observable that the two processes Annealing and CNC Machining have higher cycle time and WIP. In order to increase their capacity, their cycle should be reduced. By implementing some lean principles and changes in the production line, the future state map was created and the reduction the different types of wastes reduced. The total processing time was reduced from 409 seconds to 344 seconds.

Scaling computation with silicon photonics

Abstract

Cab Transfer Process Improvement at an Automotive Manufacturing Facility

This project is related to the improvement of cab transfer process from Painted Body Storage (PBS) area to General Assembly (GA) line. The objectives of this project are to eliminate the root cause of cab defect and to streamline the transfer process with the reduction of process cycle time. From the current process study, it is found that the lifting method causes the quality defect to the cab and the usage of different type of trolley between PBS and GA contribute to the high cycle time. The new process design has been introduced from the findings with the use of towing method and the use of common trolley for both PBS area and GA line. With the new and improved cab transfer process, the cab changing process can be eliminated. Hence, the number of operator required has been reduced, from two operators to only one operator. A trial run has been conducted with a prototype trolley and a forklift. The objectives of this project are fulfilled with the new towing method that eliminate the quality defect and the use of common trolley for both PBS and GA line resulting new cycle time of 7.13 minutes per unit from 9.77 minutes per unit. Further studies are needed for commissioning and monitoring to the new cab transfer process with the actual trolley and tow tug or buggy.

High Communication Throughput and Low Scan Cycle Time with Multi/Many-Core Programmable Logic Controllers

Programmable logic controllers (PLCs) are hard real-time embedded systems designed to interact with (through sensors and actuators) and control physical processes in pharmaceutical, manufacturing, energy, and automotive industries. PLCs are the fundamental building blocks in modern industrial automation systems; they are designed to operate in extreme, harsh environments for decades without interruption. This letter presents and evaluates a novel, scalable hardware/software architecture for multi/many-core PLCs capable of pipelining the “sensing-executing-actuating” stages of a control system and thus reducing the scan cycle time (SCT) and maintaining a high-throughput communication (HTC). SCT and HTC are two of the most important key performance indicators (KPIs) in industrial control systems because they determine the accuracy of the control algorithms.

Statistical analysis and optimization of simultaneous biological nutrients removal process in an intermittently aerated SBR

Simultaneous removal of carbon and nutrients from a synthetic wastewater in aerobic/anoxic sequence batch reactor (SBR) was investigated. The experiments were conducted based on a central composite design (CCD) and analyzed using response surface methodology (RSM). Two significant independent variables, cycle time and aeration time, were studied to analyze the process. Five dependent parameters--total COD (TCOD) removal, total nitrogen re- moval, total phosphorus removal, total Kjeldahl nitrogen removal and effluent nitrate concentration--were monitored as the process responses. The region of exploration for the process was taken as the area enclosed by cycle times (2, 4.25 and 6.5 h) and aeration times (30, 40 and 50 min/h) boundaries. The maximum COD (87.18%) and TKN (78.94%) removal efficiencies were obtained at the cycle time and aeration time of 6.5 h and 50 min/h, respectively. While the maximum TN (71.15%) and phosphorus (68.91%) removal efficiencies were obtained at cycle time of 6.5 h and aeration time of 40 min/h. As a result, high cycle time (6.5 h) and moderate aeration time (40 min/h) were found to be the optimal region for maximum carbon and nitrogen removal efficiencies.

Stabilization of the Robot Mounted Inverted Pendulum by Vision Control

In this paper the stabilization of the well known inverted pendulum problem by visual control is presented. The pendulum is mounted on the flange of an articulated robot arm. It is observed by camera and its angle of inclination is computed by image processing on a PC. For stabilization a state space controller realized with the standard robot controller is used. In summary, this system can be seen as an example of a robot with visual control. The inverted pendulum is used because it is an adequate controlled system to demonstrate advanced control algorithms. Its implementation with a robot results in some more restrictions in comparison with the pendulum mounted on a linear drive, e.g. in lower acceleration, smaller traversing range and the relatively high cycle time of the commercial robot controller. Furthermore, the integration of the camera in the closed loop control instead of an angular transmitter makes the successful realization more difficult.

Fatigue response of rat medial longissimus muscles induced with electrical stimulation at various work/rest ratios

Muscle fatigue may be a precursor to workplace musculoskeletal disorders, with the low back resulting in the most frequently injured body part. Work/rest ratios have an effect on fatigue due to the amount of rest allowance provided following muscle contraction. This study explored various work/rest ratios by electrically stimulating rat medial longissimus muscles. A 3 V stimulus with 0.2 ms pulse duration was applied at a frequency of 30 Hz. There were four stimulation groups consisting of the following duty cycles (DC) and cycle times (CT): DC25%:CT20s, DC25%:CT280s, DC75%:CT20s, and DC75%:CT180s. Muscle fatigue was measured as a decrease in M-wave amplitude and area, and an increase in M-wave duration. The results indicated that fatigue occurred immediately in each of the groups. The higher duty cycle and shorter cycle time group resulted in significantly greater fatigue than the lower duty cycle and longer cycle time group, as measured by increased M-wave amplitude and area. A longer M-wave duration was observed in the high duty cycle long cycle time group. This suggests that the combination of low duty cycle and long cycle times leads to less fatigue. In high duty cycle scenarios, short cycle times result in less fatigue.

Passive Device Integration from Silicon Technology

Passive components are indispensible parts used in electronics circuits for various functions, such decoupling, biasing, resonating, filtering, matching, transforming, etc. These passive components can be made on chips, or in PCBs, or in SMDs. SOC (system-on-chip) solutions where all passives are implemented may be long-term goals, but suffer high cost and long development cycle times at the time being. Making passive components embedded inside laminate substrates is limited on passive density. SMD solutions are by far the most popular approaches in the industry, and may still be dominant for some times. Passive components consume 70%–80% area of an electric package in a SiP solution, and therefore it is a great deal to reduce the area of passive components, in order to reduce the size of entire package. We have developed an IPD (integrated passive device) process from silicon technology to make these passive components of high-Q performance, preferably to be used in RF packages. Low-loss substrate material is used in this process, and thick Cu layer is used for high-Q inductors. From this process, we can make capacitors in 330pF/mm sq density, and the Q-factor is around 30–35 peak for a 3nH–5 nH inductor. Most importantly, the thin-film IPD process has better tolerance control than other commonly available ones, such as PCB and LTCC technologies, which may results in very repeatable electrical performance, and provides packages in high integration. For a passive function block, using BPF (band-pass-filter) as an example, an IPD filter is typically two times smaller in X-Y size and half thinner in Z-height. This makes such IPD very suitable to be integrated in a SiP package. Using some case studies (individual IPD and chip-scale-module-package), we will present how high integration can be achieved, and where are the right spots to use IPD approaches other than SAW, or SMD, or LTCC solutions for RF SiP applications.

Design and Implementation of a Cpld-Based Multilevel Inverter Depending on a Complex Programmable Logic Device (CPLD)

A complex programmable logic device (CPLD) based multilevel inverter has been designed and implemented. The design involves three main parts. The first part is the switching angle generator (SAG), which determines the switching angles from an optimized primitive angle. The second part is the switching pulse generator (SPG), which controls the drive circuit of the inverter. The timing circuit is the third part, which provides the necessary timing for both SAG and SPG. Implementing both SAG and SPG using a CPLD device mean high speed cycle time. Hence an accurate timing for the switching angles is obtained compared to other procedures that uses software for calculating and generating the switching angles, such as microcontroller. MATLAB work space has been used to acquire and analyze the inverter output via the PC sound card. Results of the implemented inverter staircase output voltage, as well as the output frequency spectrum are obtained.

Design and Implementation of a Cpld-Based Multilevel Inverter Depending on a Complex Programmable Logic Device (CPLD)

A complex programmable logic device (CPLD) based multilevel inverter has been designed and implemented. The design involves three main parts. The first part is the switching angle generator (SAG), which determines the switching angles from an optimized primitive angle. The second part is the switching pulse generator (SPG), which controls the drive circuit of the inverter. The timing circuit is the third part, which provides the necessary timing for both SAG and SPG. Implementing both SAG and SPG using a CPLD device mean high speed cycle time. Hence an accurate timing for the switching angles is obtained compared to other procedures that uses software for calculating and generating the switching angles, such as microcontroller. MATLAB work space has been used to acquire and analyze the inverter output via the PC sound card. Results of the implemented inverter staircase output voltage, as well as the output frequency spectrum are obtained.

Generalized thermo-elastodynamics for semiconductor material subject to ultrafast laser heating. Part II: Near-field response and damage evaluation

Thermal waves and near-field responses including the axial and radial displacements and stresses are investigated in a time window as wide as 10 ns using the generalized thermo-elastodynamic model of axisymmetric geometry presented in Part I. Ultrashort laser-induced thermal waves are found to be fast-attenuating; while transverse thermal stress waves are dispersive and characteristically of broadband and extremely high frequency. In addition, near-field responses and wave dispersion described by the presented model formulation are characteristically different from those modeled using parabolic transport equations for the same laser input parameters. The methodology of accumulated damage evaluation (Oh et al., 2008 [11]) making use of high cycle fatigue and time–frequency analysis is utilized to conclude that thermal stress waves induced by 500 fs ultrafast laser pulses of 0.775 μm in wavelength, 0.005 J/cm 2 in fluence and 10 μm in spot size are insufficient to initiate fatigue cracking in the silicon thin section considered in the study.

In-line Inspection Impact on Cycle Time and Yield

The semiconductor industry constantly drives for high yield and low cycle time (CT), while most current manufacturing practices consider them separately. This research investigates and exhibits the relationship between CT and yield as affected by in-line metrology inspections of production lots. Among the various factors that impact the tradeoff between CT and yield, we focus on single operation monitors and investigate their measure rate and scheduling. The research assumes a simplified production cell consisting of three operation steps that represent a typical segment in a production line. We compose and apply dynamic policies for metrology inspections via simulation and analytical methods. The aim is to concurrently reduce the CT accumulated and increase the yield achieved due to inspections. Ten inspection policies are compared under nine different operation scenarios. The results of most of the policies present a concave curve of yield versus CT. The curve illustrates that growing inspection rate increases both yield and CT until the yield reaches a maximum and then starts to decline. The cause for the yield decline is longer delay in corrective feedback to an out-of-control production tool due to longer waiting time for inspection. A cost-benefit CT-yield objective function is defined and demonstrates that the newly composed dynamic inspection policies are superior to the commonly used fixed measure rate policy. Future research could relax part of the simplified production cell assumptions in order to consider more realistic model structure and scenarios.