Short Cycle Time Research Articles

Study of ultrasonically welded thermoplastic dowel-wood board assembly

• Ultrasonic welding is a fast joining of thermoplastic dowel-wood board assembly. • Density of wood board plays an important role in ultrasonic welding. • Dowel pulling force inversely proportional to the depth of the drilled hole. • Ultrasonic thermoplastic dowel welding is not suitable for wet wood boards. This study reports on an ultrasonic welding application for the assembly of a thermoplastic dowel and a wood board. Three types of medium density particleboards (MDP) and fiberboards (MDF) were used to indicate applicability of ultrasonic welding to fix a plastic wedge dowel into the wood boards: light-weight, standard, and heavy. Plastic wedge dowels made of resin nylon thermoplastic polyamide PA66 were used to compose ultrasonically welded wood boards’ joints. Ultrasonic welding is a joining technique without any additional substances, such as adhesives or solvents. It possesses local heating of only the joint area, short cycle times in the range of just a few seconds, and comparatively low cost-efficiency. During the ultrasonic consolidation process, energy generated from an ultrasonic transducer is transferred to the joint components (dowel – wood board) in the form of ultrasonic oscillation. The quality of the welded joint is mainly influenced by the density of the wood board, the quality of wood particles bonding, the depth and diameter of the drilled hole. The size of the contact area of the drilled hole (hole geometry, density and the size of hole walls) is also very important because the molten thermoplastic requires enough space to penetrate and settle to form a solid assembly.

Gluing of panel parquet products in passage presses

The article indicates the weak points of parquet assembly and gluing automatic lines with a relatively short cycle time, which is usually a press section based on positioning equipment, which is proposed to be replaced by straight-through presses of a simplified design. A method for gluing wooden floor coverings based on a through-feed press is proposed. To eliminate the spread of pressure acting on wood blanks of different thickness, it is proposed to use rubber gaskets based on spongy rubber, glued to the working surfaces of the tracks. The values of the actual spread in the thicknesses of the parquet planks and the mechanical characteristics of elastic pads are experimentally determined. The article provides conclusions about the suitability of a continuous press with tracks equipped with elastic elements for the production of panel board parquet and the feasibility of introducing such equipment.

Preparation and properties of aniline chain‐extended thermoplastic epoxy resin using triphenylphosphine as catalyst

Thermoplastic resins have been widely used in fiber reinforced polymer composites because of its recyclability and short cycle times. However, the high viscosity after heating and melting restricts its infiltration on the surface of fiber. In this study, a series of thermoplastic epoxy resins were prepared via the chain extension reaction of epoxy groups with liquid aniline using triphenylphosphine (TPP) as catalyst. The relationship between polymer network structure and performance was comprehensively investigated. The solubility tests indicated that excessive aniline or TPP facilitated the crosslinking of resins. Besides, on the premise of thermoplasticity, appropriate TPP could increase the degree of chain extension, molecular weight, and glass transition temperature of resins. Furthermore, the in‐situ polymerization process facilitated infiltration between epoxy resin and the fibers before chain extension reaction. The bending test showed that the flexural performance of the sample with 2 phr of TPP was improved by 38.8%. Therefore, this work provides a feasible method to prepare the thermoplastic epoxy resins and its fiber‐reinforced composites with good mechanical properties.

Experimental Investigation of In-Plane Shear Behaviour of Thermoplastic Fibre-Reinforced Composites under Thermoforming Process Conditions

In order to meet environmental regulations and achieve resource efficiency in the series production of vehicles, recyclable polymer composites with a high strength-to-weight ratio are increasingly being used as materials for structural components. Particularly with thermoplastic fibre-reinforced polymers or organo-sheets, the advantage lies in the tailored mechanical properties of the final component by adapting the orientation of fibres based on the direction of loads. These components produced by thermoforming organo-sheets also offer a cost benefit and short cycle times. During the thermoforming process, the shear behaviour of the organo-sheet is the most dominant and determines the mechanical properties and quality of the resulting component. However, the current standard for characterising the shear behaviour of organo-sheets does not consider the strain and cooling rates inherent in the thermoforming process. This research investigates the influence of thermoforming process parameters on the shear behaviour of organo-sheets with a new methodology combining DSC and DMA experiments. During the thermoforming process, the transition of the matrix material from a molten state to a solid state is dictated by the crystallisation kinetics and their dependence on heating and cooling rates. Thus, non-isothermal DSC scans, which correspond to a temperature cycle in a thermoforming process, are used in the DSC experiments to establish the relationship between the recrystallisation temperature of the organo-sheet material and the cooling/heating rates in the thermoforming process. In order to achieve thermoforming-process-relevant cooling rates, fast scanning calorimetry (Flash DSC) is used in addition to conventional DSC measurements. DMA experiments carried out with 45° fibre orientation show that the recrystallisation temperature consequently influences the shear storage modulus of the organo-sheet. The results from DSC measurements show a shift of recrystallisation temperatures to lower temperatures as the cooling rate increases. The combined analysis of results from the DSC and DMA experiments supports the findings and shows the influence of the process temperature, cooling rate and strain rate on the recrystallisation temperature and, in turn, the shear behaviour of organo-sheets. Thus, a recommendation for establishing a new standard for characterising the shear behaviour of organo-sheets is made.

Investigation of mid-infrared rapid heating of a carbide-bonded graphene coating and its applications in precision optical molding.

Graphene interacts with electromagnetic waves strongly in a wide range from ultra-violet to far-infrared, making the graphene coating suitable for a variety of applications. In this study, a novel localized rapid heating technique utilizing micro-patterned silicon stampers with carbide-bonded graphene coating, which directly heats up by absorbing mid-infrared light radiation, is implemented in rapid precision optical molding. The graphene network, as a functional coating to obtain thermal energy and improve the anti-adhesion of the mold surface, can heat up the mold surface rapidly (up to 18.16 K/s) and evenly above glass transition temperature over a large area within several seconds. Since the graphene coating was around tens of nanometers (∼45 nm) thick, the rapid precision surface molding process can be shortened into tens of seconds. Furthermore, the thermal response and repeatability of the graphene coated silicon wafer is investigated by repeated thermal cycling. This novel rapid precision surface molding technique is successfully tested to replicate grating structures and periodic patterns from silicon molds to thermoplastic substrates with high accuracy. Compared with conventional methods, this new approach can achieve much higher replication fidelity with a shorter cycle time and lower energy consumption.

Manufacturing of bio‐based thermoplastic composites using industrial process for high‐volume applications

AbstractThe use of high strength‐to‐weight ratio materials in automotive component is a solution to reduce fuel consumption and decrease greenhouse gases emissions. Fiber reinforced composite materials are believed to enable weight saving that cannot be achieved with metals while meeting component mechanical requirements. Moreover, the use of renewable bio‐based composites is seen as a key aspect to further address the reduction of greenhouse gases emission. However, composite manufacturing process must meet short cycle time, performance, and cost targeted by the transportation industry in order to be considered as replacement materials. This article investigates the use of an industrial compression—direct long fiber thermoplastic (D‐LFT) process line to manufacture cellulose reinforced bio‐based polyamide parts in order to increase the penetration of sustainable materials in the transportation sectors. Process evaluation and composite performance were first carried out on a simple 2D geometry. Then the use of 100% bio‐sourced materials with the high‐throughput D‐LFT process was validated with the manufacturing of an automotive composite seat pan demonstrator. Bio‐based composite parts were successfully manufactured. Tensile properties in the range of glass fiber reinforced polypropylene composites traditionally used with the D‐LFT process were measured, validating the potential of cellulose–biopolyamide composite materials for industrial applications.

Applications of nDATA for screening, quantitation, and identification of pesticide residues in fruits and vegetables using UHPLC/ESI Q-Orbitrap all ion fragmentation and data independent acquisition.

High sample throughput and effective multiresidue methods for screening, quantitation, and identification are desired for the analysis of a large number of pesticides in routine monitoring programs for food safety. This study was designed to explore the use of an UHPLC/ESI Q-Orbitrap nontarget data acquisition for target analysis (nDATA) workflow for screening 655 pesticides and quantifying a small group of 46 most likely incurred pesticide residues in fruits and vegetables in a single analysis. High-resolution mass spectrometers such as the Q-Orbitrap offer unique applications for pesticide analysis using full MS scan with data independent acquisition (DIA) or all ion fragmentation (AIF) scan. The experiments were designed to achieve a balance between selectivity and cycle time by considering parameter settings such as mass resolution and the number of mass isolation windows or isolation window widths. Coupled with ultra-high performance liquid chromatography (UHPLC), both full MS/DIA and full MS/AIF nDATA workflows were evaluated for screening, quantification, and identification in a single analysis. In general, UHPLC/ESI full MS/vDIA detected more fragment ions per pesticide than AIF when one to four fragments were compared. UHPLC/ESI full MS/vDIA and AIF generated comparable quantitative results, but the latter provided slightly better repeatability likely due to its shorter cycle time and more scans across a chromatographic peak. UHPLC/ESI full MS/vDIA may be preferable for screening, quantitation and identification when the testing scope covers a few hundreds of pesticides in a single analysis.

Optimization and Rejection Analysis of IC Engine Rocker Arm

Abstract: Today, many technical products need high-precision cylindrical bores which are used, e.g. as a fit or as guidance elements for pistons and shafts. They often need geometric and form accuracy with tolerances less than 1 μm, surface qualities with a roughness less than 1 μm and a high wear resistance. To reach higher production accuracy and better process stability in shorter cycle times, new approaches for the regulation of an automated honing process have to be developed. Due to the great demands regarding the surface roughness which has a great influence on the service life and reliability of parts and the researches of the technical and economical performances of finishing processes were made to optimize the process parameters and constructive parameters of the abrasive tools Keywords: Surface roughness, Analysis, Honing, process parameter, Rocker arm

Enhancing dropwise condensation on downward-facing surfaces through the synergistic effects of surface structure and mixed wettability

In this paper, the condensation performance and the dynamic behavior of condensed droplets on a downward-facing structured surface with mixed wettability are numerically investigated using a thermal multiphase lattice Boltzmann model, with a focus being placed on exploring the enhancement mechanism of dropwise condensation on downward-facing structured surfaces. The numerical investigation shows that the downward-facing structured surface with mixed wettability exhibits much better condensation performance than those with homogeneous wettability owing to the synergistic effects of surface structure and mixed wettability, which increase the droplet departure frequency and prevent the flooding phenomenon. Furthermore, it is found that the dynamic behavior of condensed droplets on the downward-facing structured surface with mixed wettability can be divided into three stages, i.e., the nucleation-growth stage, the coalescence-slip stage, and the stick-departure stage. Particularly, there exists a competition between the time of the first stage and that of the third stage in terms of the contact angle of the pillar top (θtop). The former reduces but the latter increases with decreasing θtop, because the contact lines are always pinned at the edges of the pillar top during the third stage when θtop is small. An optimal θtop is therefore found, which provides the best droplet dripping rate by achieving a suitable balance between a large droplet departure volume and a relatively short condensation cycle time.

PAT soft sensors for wide range prediction of key properties of diesel fuels and blending components for the oil industry

In an oil refinery, all decisions about the immediate destiny and processing of oil streams and blended products depend on the preliminary determination of their properties. These are obtained through standard methods, which are time consuming, expensive and require specialized personnel. Furthermore, their outcomes only become available after a considerable delay, significantly affecting plant activities. In this work, we present soft sensors based on Process Analytical technology (PAT) for accurately predicting eleven critical diesel properties in a wide variety of diesel fuel fractions and blends collected from an industrial refinery. The soft sensors were developed from FTIR-ATR spectra, through the optimization of preprocessing, band selection, spectral resolution tuning and bilinear modeling, under real plant operating conditions (GALP oil refinery plant). Quality parameters are estimated in a short cycle time with comparable accuracies to reference methods, enabling faster response times and decision making, while lowering the experimental overload in the laboratory.

CNN-Based Defect Inspection for Injection Molding Using Edge Computing and Industrial IoT Systems

Currently, the development of automated quality inspection is drawing attention as a major component of the smart factory. However, injection molding processes have not received much attention in this area of research because of product diversity, difficulty in obtaining uniform quality product images, and short cycle times. In this study, we proposed a defect inspection system for injection molding in edge intelligence. Using data augmentation, we solved the data shortage and imbalance problem of small and medium-sized enterprises (SMEs), introduced the actual smart factory method of the injection process, and measured the performance of the developed artificial intelligence model. The accuracy of the proposed model was more than 90%, proving that the system can be applied in the field.

A Methodology of Task Allocation to Design a Human-Robot Assembly Line

There are successful cases in lean manual assembly lines; however, in some cases, such as the ease of assembly in quicker cycle time, the designs are not satisfactory and must be transformed to semi-automation. This research studies human-robot task allocation when designing for semi-automation considering not only time-cost effectiveness as in the existing research but also assembly difficulty and ergonomic issues. A proposed methodology optimally determines what tasks should be performed by humans or robots, at which station, and in what sequence. A multi-objective linear programming (MOLP) model is proposed to simultaneously minimize total operating cost, cycle time, and ergonomic difficulty. Solving the model has two approaches: with and without optimal weights. The methodology is applied to a Lego-car assembly line. To illustrate the benefits of the proposed MOLP, a comparison between it and three single-objective models is made. Results show that the optimal-weight MOLP yields a better performance (a shorter cycle time, a lower cost, and especially, a significant ergonomic improvement) when compared to the other MOLP and single-objective models.

Numerical Modelling of Bond Strength in Overmoulded Thermoplastic Composites

Overmoulding of thermoplastic composites combines the steps of thermoforming and injection moulding in an integrated manufacturing process. The combination of continuous fibre-reinforced thermoplastics with overmoulded polymer enables the manufacturing of highly functionally integrated structures with excellent mechanical properties. When performed as a one-shot process, an economically efficient manufacturing of geometrical complex lightweight parts within short cycle times is possible. However, a major challenge in the part and process design of overmoulded thermoplastic composites (OTC) is the assurance of sufficient bond strength between the composite and the overmoulded polymers. Within the framework of a simulation-based approach, this study aims to develop a methodology for predicting the bond strength in OTC using simulation data and a numerical model formulation of the bonding mechanisms. Therefore, a modelling approach for the determination of the bond strength depending on different process parameters is presented. In order to validate the bond strength model, specimens are manufactured with different process settings and mechanical tests are carried out. Overall, the results of the numerical computation are in good agreement with the experimentally determined bond strength. The proposed modelling approach enables the prediction of the local bond strength in OTC, considering the interface conditions and the processing history.

Laser cladding of vanadium carbide interlayer for CVD diamond growth on steel substrate

The chemical vapor deposition of diamond film on steel substrate remains with main drawbacks demanding a proper solution. Some proposed interlayers tackled with the high carbon diffusivity into steel and with the graphitic sp2 bonds catalyzed by transition metal. However, the large mismatch of the coefficient of thermal expansion between steel and diamond produces cracked and delaminated diamond films. Thermodiffused vanadium carbide (TDVC) interlayer for straight CVD diamond deposition on steel, showed disruptive results; nevertheless, the coating thickening is limited to substrate with high carbon content and low alloy steel. This work introduces the use of laser cladding (LC) to form an intermediate layer of vanadium carbide (VC) from V4C3 powder. The LC process has a short cycle time and a high VC growth rate (5.6 μm/min). Comparing with TDVC, it represents a reduction of approximately 26 times in the process cycle time. We used AISI D6 steel as substrate and overlapped VC layers to raise the coat thickness up to 25 μm. The layers showed good adherence, low porosity, and the formation of V8C7 phase. Diamond films 2.8 μm thick were deposited by hot filament chemical vapor deposition (HFCVD) at 700 °C. The Raman spectroscopy of the diamond film on four overlapped VC layers (25 μm thick) showed a compressive residual stress of 2.7 GPa. The residual stress reduction was 1.8 GPa, when compared with the 7 μm thick single cladded VC layer.

WaveRAPID-A Robust Assay for High-Throughput Kinetic Screens with the Creoptix WAVEsystem.

Surface-based biophysical methods for measuring binding kinetics of molecular interactions, such as surface plasmon resonance (SPR) or grating-coupled interferometry (GCI), are now well established and widely used in drug discovery. Increasing throughput is an often-cited need in the drug discovery process and this has been achieved with new instrument generations where multiple interactions are measured in parallel, shortening the total measurement times and enabling new application areas within the field. Here, we present the development of a novel technology called waveRAPID for a further-up to 10-fold-increase in throughput, consisting of an injection method using a single sample. Instead of sequentially injecting increasing analyte concentrations for constant durations, the analyte is injected at a single concentration in short pulses of increasing durations. A major advantage of the new method is its ability to determine kinetics from a single well of a microtiter plate, making it uniquely suitable for kinetic screening. We present the fundamentals of this approach using a small-molecule model system for experimental validation and comparing kinetic parameters to traditional methods. By varying experimental conditions, we furthermore assess the robustness of this new technique. Finally, we discuss its potential for improving hit quality and shortening cycle times in the areas of fragment screening, low-molecular-weight compound screening, and hit-to-lead optimization.

Sequestering Biomass for Natural, Efficient, and Low-Cost Direct Air Capture of Carbon Dioxide (Version 2)

Many corporations and governments aspire to become Net Zero Carbon Dioxide by 2030-2050. Achieving Net Zero CO2 requires understanding where energy is produced and consumed, the magnitude of CO2 generation, and the Carbon Cycle. It is unreasonable to assume that fossil fuel can be completely replaced, and thus, atmospheric CO2 will continue to accumulate. Many prior proposed solutions focus on reducing future CO2 emissions from continued use of fossil fuels. Examination of these technologies exposes their limitations and shows that none offer a complete solution. Direct Capture technologies are needed to reduce CO2 already in the air. However, some of those already proposed would lead to a very high cost of Carbon Capture, Use, and Storage (CCUS). Biofuels can help achieve reduction goals. However, two of the six carbons in sugar fermented to bioethanol produce CO2 per the stoichiometry of the reaction. Four carbons go to ethanol, which go back to the atmosphere upon burning in an engine. Thus, without CCUS, which most current bioethanol plants do not practice, bioethanol would at best be sustainable. The only way to permanently remove CO2 already in the atmosphere is to break the Carbon Cycle by growing biomass from atmospheric CO2 and permanently sequestering that biomass carbon. Permanent sequestration can be achieved in landfills modified to discourage biomass decomposition to CO2 and methane. Sequestration of biomass carbon is proposed as a simple and natural means of Direct Capture. Tree leaves are proposed as a good source of biomass for this purpose. Left unsequestered, leaves decompose with a short Carbon Cycle time constant releasing CO2 back to the atmosphere. Leaves represent a substantial fraction of the total biomass generated by a tree when integrated over a tree’s lifetime. High yield crops, such as switchgrass would also be a good source of biomass. The cost for growing switchgrass and sequestering it in a landfill is estimated to be on the order of $120/mt CO2 for a conservative yield of 3.5 tons/acre and may be reduced to as low as $88/mt CO2 if the development of high yield switchgrass is successful. This compares to an estimated cost of CCUS from the Steam Reforming of Methane to produce hydrogen of about $190/mt. Thus, sequestration of biomass is shown to be a natural, carbon efficient, and low-cost method of Direct Capture.

An experimental investigation of the cooling and heating performance of a gravity die casting mold with conformal cooling channels

• Conformal cooling was applied successfully in gravity die casting mold. • Cooling efficiency was increased with cooling channels around the pusher pin regions. • Cycle time was reduced by 28% with conformal cooling channel in gravity die casting. • The average grain size of casted parts was reduced by 13.5%. In the gravity die casting process, cooling directly affects the unit cost and microstructure quality of casting products. In the conventional manufacturing methods, cooling channels in gravity casting molds are usually produced linearly in circular profiles. When cooling is not conformal, molding defects such as hot spots and distortions form in the products. This study investigated the effects of cooling channels on the casting steps and final properties of the products in standard and conformal cooling gravity die casting molds. Numerical analysis results were compared with the experimental data and then were verified. The pressure losses in cooling channels, the times for molds to reach the required temperature and the cycle times were all measured. The pressure losses in standard and conformal cooling channels were measured at 5250 Pa and 12100 Pa, respectively. In addition, a more homogeneous mold surface temperature distribution was achieved in the conformal cooling mold, as well as a 28% shorter cycle time. The average particle size of the parts cast with conformal molds was 13.5% smaller than those cast with standard molds. Finally, the mechanical properties of the parts cast with conformal cooling channel molds were found to be better than those cast with standard channel molds.

Tool and Die Making, Surface Treatment, and Repair by Laser-based Additive Processes

This paper explores the possibilities to use laser-based additive processes to make, surface treat and repair/remanufacture tools, dies and molds for cold working, hot working, and injection molding. The failures encountered in these applications are described. The materials used conventionally and in the laser additive processes are accounted for. The properties of the tools, dies and molds made by Laser-based Powder Bed Fusion (L-PBF) are as good as and in some cases better than the properties of those made in wrought materials. Shorter cycle time, reduced friction, smaller abrasive wear, and longer life cycle are some of the benefits of L‑PBF and Directed Energy Deposition with powder (DED-p) (or Laser Metal Deposition with powder, LMD‑p, or Laser Cladding, LC). L‑PBF leads to higher toolmaking costs and shorter toolmaking lead time. Based on a review of conducted investigations, this paper shows that it is possible to design and make tools, dies and molds for and by L‑PBF, surface functionalize them by DED-p (LMD‑p, LC), and repair/remanufacture them by DED-p (LMD‑p, LC). With efficient operational performance as the target for the whole tool life cycle, this combination of L‑PBF and DED-p (LMD‑p, LC) has the greatest potential for hot working and injection molding tools and the smallest for cold working tools (due to the current high L‑PBF and DED-p (LMD‑p, LC) costs).

Variety of national innovation systems (NIS) and alternative pathways to growth beyond the middle-income stage: Balanced, imbalanced, catching-up, and trapped NIS

• Find a close match between the types of NIS (national innovation systems) to economic growth. • Identifies two NIS-based pathways to achieve sustained economic catch-up. • The one pathway is the balanced and mixed NIS, such as Ireland, Spain, Hong Kong, and Singapore. • The other pathway is the imbalanced and catching-up NIS, such as Korea, Taiwan, and China. • The catching-up NIS boasts high localization and diversification, compared with the trapped NIS. This study uses the US patent data of 32 to 35 economies to measure, classify, and analyze the evolution and performance of their respective national innovation systems (NIS) or technology clubs, with a focus on those economies that sustained growth beyond the middle-income stage. The NIS is measured in terms of five variables, namely, knowledge localization, technological diversification, cycle time of technologies, originality, and decentralization. The cluster analysis identifies five major NIS clusters that are either balanced or imbalanced in terms of the relative values of the five NIS variables. Growth equation regressions confirm two pathways to achieve catching-up toward the high-income status. The one pathway has been identified for Ireland, Spain, Hong Kong, and Singapore, which all belong to the balanced and mixed NIS cluster and are joined recently by India and Russia, thus achieving “balanced catching-up”. The other pathway has been identified for Korea and Taiwan, which created imbalanced and catching-up clusters, and is recently joined by China. In contrast to these two groups, we have also identified the trapped NIS consisting of those economies perceived to be stuck in the middle-income trap, such as Brazil, Argentina, Chile, Mexico, South Africa, Malaysia, and Thailand. The imbalanced and catching-up NIS is characterized by short cycle time of technologies, low originality, high localization, and high diversification compared with the trapped NIS with the exactly opposite attributes. By contrast, the balanced and catching-up group is characterized by all of these NIS variables that are balanced at intermediate values.

Time adapted linear driving force model for gas adsorption onto solids

• Frequently used models cannot predict kinetics data for all adsorption pairs. • Introduces a time adapted linear driving force model for adsorption kinetics. • Validates the proposed model with experimental data of various adsorbent-adsorbate pairs. • Proposed model can successfully predict the entire adsorption process. • Diffusion time constant has been calculated for all the studied pairs. Adsorption systems are promising for sustainable energy applications, like a low-grade thermal energy-driven heat pump, gas storage, water desalination, and thermal energy storage. The dynamic uptake of adsorbate onto the porous adsorbent plays a crucial role in determining the performance of these adsorption systems. This paper presents a new kinetics model to precisely describe the adsorption dynamics for different adsorbate – adsorbent pairs. A detailed mathematical derivation of this model, along with validation for several adsorption pairs, is presented in this paper. The most significant drawback of traditional kinetics models such as Fickian diffusion, linear driving force, and semi-infinite model has been their time-dependent deviation from experimental data. The proposed model can predict the adsorption dynamics accurately both during the initial unsaturated condition as well as during the later period when the adsorbent is near its saturated condition. Thus, one can use this model for predicting the adsorption system performance for both short and long cycle times.