Browse Topic: Drying
AMS6885/2 gives specific information about the qualification program for unidirectional carbon fiber tape epoxy repair prepreg capable of curing under vacuum for repair of carbon fiber reinforced epoxy structures. The prepreg system shall include an epoxy film adhesive to be applied in a co-bonding process with the prepreg for solid laminate and sandwich bonding.
Master Bond EP40 is a two-part, room temperature curing epoxy for bonding, sealing, coating, and encapsulating. EP40 bonds well to a variety of substrates, including naval steel, the primary structural metal used in the shipbuilding industry. Master Bond Inc., Hackensack, NJ To reduce its environmental impact and pollution, the shipping industry is investigating methods to construct more lightweight ships. One potential method is using adhesive bonding techniques to replace traditional welding and riveted joints on ships to fabricate lighter ships with smaller carbon footprints. However, adhesives age and deteriorate when exposed to moisture, high temperatures, and ultraviolet light. This makes it necessary to understand how they age in maritime environments to determine whether they can truly replace traditional welding techniques. To this end, researchers at Centro de Investigación en Tecnologías Navales e Industriales (CITENI) and Centro de Investigación TIC (CITIC) developed a new method for studying adhesive aging on naval steel substrates. Master Bond EP40 was selected as the test adhesive for this method due to its strong performance and suitability for marine conditions. By using EP40, the team ensured that the observed adhesive bonding behavior would reflect a high-quality epoxy's potential in ship structures. The goal was to evaluate how EP40 bonds to naval steel and how the bulk epoxy material would behave in seawater to provide insights into the construction of lighter ships using this approach.
Secondary battery electrodes are made by mixing active materials that store electrical energy, conductive additives that help the flow of electricity, and binders, which act as a kind of adhesive. There are two methods for mixing these materials: the wet process, which uses solvents, and the dry process, which mixes solid powders without solvents. The dry process is considered more environmentally friendly than the wet process and has gained significant attention as a technology that can increase the energy density of secondary batteries. However, until now, there have been many limitations to achieving a uniform mixture of active materials, conductive additives, and binders in the dry process.
The Autoclave processing is commonly used in manufacturing high-performance fibre-reinforced thermoset composite components in the aerospace industry. Variations in the cure cycle, sometimes even apparently minor deviations from the prescribed cure cycle, can harm the laminate properties. Given the costly and time-consuming autoclave manufacturing process, there is a strong need to cure the maximum number of parts in the shortest possible time without compromising quality. In order to achieve high-rate automated manufacturing with the optimized autoclave process, it is important to construct a digital twin modelling approach to mirror the physical composite curing process in the virtual domain based on the integration of high-fidelity multi-physics models. The resulting digital twin includes a thermal CFD model, a thermo-chemo-mechanical module, and an efficient and accurate block coupling between these two modules. The customized Abaqus driven by local and spatial variation of the turbulence-induced heat transfer coefficient (HTC) imposed through one-way coupling determines the thermo-mechanical response in composite parts. Using the developed digital twin tool (SMARTCLAVE), HTC's spatial and temporal variation can be generated digitally without invoking an expensive and time-consuming experimental approach. The predicted local boundary conditions are used in SMARTCLAVE to determine the cure kinetics, temperature distribution, and thermal-mechanical response that drives the residual stress and distortion of composite parts after curing. The accuracy of the digital twin for autoclaving is demonstrated first using a benchmark problem followed by the capability demonstration with a single-part L-beam assembly. The benefits of using the digital twin tool are illustrated via the optimal placement of multiple parts in an autoclave to balance the throughput and quality.
Ultrasonic Testing (UT) is a typical Non-destructive testing (NDT) method for examining the structural components for aircraft production. Manufacturing aircraft made of fiber metal laminates (FML) includes cascaded steps such as placement of aluminum, glass prepreg, adhesive, doublers, stringers, vacuum bagging and curing in an autoclave. Quality control (QC) is performed first at the layup of the component (without stringers) after curing and the quality assessment is visually evaluated. The manually performed examination of anomalies is very time-consuming. In addition, conducted NDT inspection using a manual UT phased array for Glass Reinforced (GLARE®) FML of A380, it lacked the high capacity of data and additionally an evaluation software.
This specification covers two types of electrically conductive, elastomeric polythioether sealing compounds that cure at room temperature. The sealing compound is supplied as either a two-component system or as premixed and frozen.
This specification covers fuel-resistant, two-component polysulfide synthetic rubber compounds which cure at room temperature.
In a world of ever-increasing global consumption fueled by the immense thirst for electronic technology and information transmission, we find ourselves in a critical situation with the world supply of electronic components drying up. Demand for electronic devices has risen sharply due to the Covid-19 outbreaks, which forced the entire world to work in isolation, driving the unprecedented need for integrated circuits (IC). While development has been keeping pace during this crisis, we expect more from our devices.
This recommended practice describes the materials, related equipment, and particular processing techniques utilized in process science curing of composite hardware where pressure is imparted specifically to the resin of curing composites. Included as Appendix "A" to this ARP is a discussion of the particular techniques developed for a processing science philosophy which has consistently produced void and porosity-free, large area, thick composite structures.
This PS, AMS2980/4, specifies the batch release and delivery requirements for epoxy resin systems (base resin and curing agent) used for wet lay-up repair purposes.
Additive manufacturing, also known as 3D printing, allows the fast and cost-effective production of complex high-quality components in a range of materials. The rise of this technology has been fast, and it is rapidly altering the manufacturing landscape. In 2019, the global additive manufacturing market size was valued at $11.58 billion and is predicted to grow at a CAGR (compound annual growth rate) exceeding 14% from 2020 to 2027 (GVR). Additionally, research from Deloitte shows that additive manufacturing is empowering industry 4.0.
Additive manufacturing, also known as 3D printing, allows the fast and cost-effective production of complex high-quality components in a range of materials. The rise of this technology has been fast, and it is rapidly altering the manufacturing landscape.
The development of new components that have a structural commitment and still achieve mass reduction is becoming increasingly complex and sophisticated materials for production for the automotive market for commercial and passenger vehicles. To achieve this level of demand the use of composite materials such as carbon fiber, glass fiber or a compound of the two has become a reality, however the production rate was still considered a problem for medium volume parts (up to one hundred thousand parts per year). The work demonstrates the construction and simulation of a PoC (proof of concept) using these composites in a warm stamp process where the material a thermoset composite plate is preheated to the working temperature, then it is inserted in a tool preheated stamping, remaining closed for a few minutes where the material is consolidated and then the part is extracted already cured without the need for cooling, thus ensuring the projected production tackt compared to the autoclave curing process that can take hours. The PoC was designed with the aim of evaluating stamping conditions such as: spherical conformation, constant cross section and depth reduction, characteristics that are considered classic problems of the stamping process. Therefore, the work presents a viable proposal to produce items for the automotive market for commercial and passenger vehicles.
Conventional adhesives like epoxy that are used to bond plastic, ceramics, and wood are typically designed to cure using moisture, heat, or light. They often require specific curing temperatures, ranging from room temperature up to 80 °C. The curing process is necessary to cross-link and bond the glue with the two secured surfaces as the glue crystallizes and hardens to achieve its final strength.
Male pipe threads, including male dryseal pipe threads, when made into assemblies or installed into ports, will generally leak if not covered with a sealant. This SAE Recommended Practice is intended as a guide to assist designers and/or users in the selection and application of various types of thread sealants. The designers and users must make a systematic review of each type and application and then select the sealant to fulfill the requirements of the application. The following are general guidelines and are not necessarily a complete list.
This SAE Recommended Practice defines a procedure for determining the cleavage strength of an adhesive used for bonding automotive oily metal substrates.
In lightweight structures with dissimilar metal designs, structural adhesive joining is a potential joining method. Adhesives help in reducing galvanic corrosion by minimizing physical contact between two dissimilar metals. Along with adhesives, fasteners are often used as a secondary joining method to hold the assembly together during adhesive curing. Therefore, a hybrid joint which is a combination of adhesives and mechanical fasteners is potential joining method to join dissimilar metals. However, when two dissimilar metals such as aluminum to steel are joined with hybrid joint by adhesive curing at elevated temperature, the distortion of assembly is observed when cooled at room temperature. This is due to the mismatch between coefficients of thermal expansion of aluminum vs steel. The adhesive may also experience residual stress and fracture. In this study, adhesive curing induced distortion is studied using 1.1 meter-long specimens of aluminum to steel hybrid joint assembly. The base materials consist of 4.8 mm thick aluminum 6061 T6 joined to 1 mm thick UHSS with 30 mm adhesive overlap. One-part heat cured structural epoxy adhesive was used in hybrid joint. Variables which may have effect on distortion are identified. The variables included are adhesive layer thickness, adhesive material type, fastener type (rivet vs. screw), fastener spacings, fastener clearance hole size and adhesive curing temperature. Coordinate Measuring Machine (CMM) was used to measure the assembly distortion. It is shown that, adhesive curing induced distortion can be controlled using variables chosen. Among all the variables, adhesive layer thickness, fastener spacing and fastener clearance hole size have significant impact on distortion. Fasteners act as constraint and affect the distortion. Higher fastener spacing and higher clearance hole size increased distortion of assembly considerably. Adhesive material type, adhesive curing temperature has minimal effect on assembly distortion
This SAE Aerospace Standard (AS) establishes the surface pretreatment, temperature, and baking time required to cure AS5272 lubricant when it is applied over the surfaces of manufactured parts of various metals.
To protect ship equipment of river and sea transport, it is suggested to use polymeric protective coatings based on epoxy diane oligomer ED-20, polyethylene polyamine (PEPA) curing agent and filler, which is a departure from industrial production. Thus the purpose of the work is analysis of major dependency of the properties on the content of fillers that allowed to revealed the critical filler content (furnace black) in composites to form a protective coating with the required set of characteristics. The infrared (IR) spectral analysis was used to investigate the presence of bonds on the surface of particles of the PM-75 furnace black, which allows us to assess the degree of cross-linking of the polymer. The influence of the content of dispersed furnace black on the physicomechanical and thermophysical properties and the structure of the protective coating is investigated. For the formation of the coating with increased adhesive properties, the optimum content of the additive is q = 25 parts by weight (pts.wt.), due to the increase in the number of C—O, C—C, C═O, C═C, C═O, and O═C—H bonds. For the formation of the coating with increased cohesive properties, the optimum content of the additive is q = 20 pts.wt., which is associated with the maximum compaction of the polymer spatial net. On the basis of the analysis of the surface of the composite fracture, a homogeneous topology of the fracture surface was found which characterizes the viscous state of material destruction at the content of the additive q = 5 pts.wt., which provides significant improvement of the physical and mechanical properties of the materials developed. Additionally, it was found that when the PM-75 particles were introduced at the content of q = 10-30 pts.wt., the uniformity of the structure is retained, but its abnormal similarity is observed. This allowed us to determine the optimal content of the additive (q = 20 pts.wt.) for the formation of coatings with high cohesive strength in the complex.
Sandwich panels made of Nomex honeycomb core and fiber reinforced face sheets are a major component of aircraft interior parts. A common way to locally increase the strength of such panels, e.g. for load introduction, is the local thickening of the face sheets with additional prepreg layers. Curing of strengthened panels without further processing of the core leads to higher flatness tolerances as well as residual stresses. Machining of the core in the strengthened areas is possible, but expensive due to high machine costs and additional cleaning processes. In this paper a new process for the reduction of the residual stresses in strengthened areas, as well as improved bonding between core and face sheets is presented. The process is based on local reduction of the compressive strength in the surface area of the honeycomb core, which allows for controlled, irreversible deformation at curing pressure. For the reduction of compressive strength, a concept based on a robot guided tool with multiple blades is presented. The process parameters impacting the compressive strength after weakening are derived based on a model based analysis. A testing tool was built, and a series of tests was performed, in order to quantify the impact and to select suitable parameters. It was found that the remaining compressive strength depends mainly on the cutting pattern, the blade distance and the cutting depth. A Further reduction of compressive strength was achieved by bending the remaining structures after the cutting process. In order to validate the process, surface flatness, as well as bonding strength between core and face sheets have been measured. In addition to the flat integration of a large amount of additional prepreg layers it has been found that the bonding strength increases up to 30% due to increased bonding surface of the honeycomb core.
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