PA66 GF30 Research Articles

Fatigue and wear performance of bioepoxy vacuum-infused and autoclave-cured E-glass fiber reinforced polymer composite gears in mesh with a steel pinion

Polymer composite gears are under investigation as a promising solution to mitigate the performance gap between polymer and metal gears. The study presented in this paper evaluates the fatigue and wear performance of E-glass fiber reinforced polymer composite gears. The E-glass fibers are vacuum infused with bioepoxy, followed by autoclave curing. High-speed milling is utilized to fabricate the gears, which are then subjected to testing at torques ranging from 0.5 to 0.8 Nm. Gear failure modes predominantly include wear combined with tooth edge intra-bundle fiber delamination due to fatigue, followed by extensive inter-ply delamination just prior to failure. Gear tooth wear volume demonstrates a nearly linear correlation with the number of cycles, with accelerated wear rates observed at higher torques. E-glass fiber polymer composite gears exhibit a shorter service life and a higher wear coefficient compared to our previously developed carbon fiber reinforced polymer composite gears. However, their performance remains fair, with a service life between that of PA6 GF30 and PA66 GF30 glass fiber reinforced gears.

Applicability of memory rules during cyclic stress–strain response of polymers PA6 and PA66 GF30

Polymers are rapidly emerging materials that are taking over the place in structural applications formerly reserved for metals. Structural materials require reliable load-bearing capability during the entire lifetime of products. Available simulation tools already offer constitutive models that are well applicable to metals but have not yet been approved for polymers. Typically, models with kinematic hardening incorporate Masing rule complemented by three memory rules to simulate the cyclic response of metals during variable loading. Conversely, the research presented here has been focused on polyamides as a load-bearing-capable substitute for metals in low-cycle fatigue applications. In particular, it has been studied whether natural PA6 and glass-fibre-reinforced PA66 GF30 follow the memory rules during variable amplitude loading. Incremental step tests were performed initially to determine the material parameters of the stabilised response. A high variation for the stabilised stress–strain response could reach up to 42.5% for PA6 and 24.5% for PA66 GF30 during incremental step tests. Moreover, the natural PA6 exhibited a higher degree of symmetry of the stress–strain result with less variation in stress than the reinforced PA66 GF30. Next, variable amplitude tests were performed which contained the three memory rules in the load history. The stress scatter during the variable amplitude loading in repeated tests has been observed between approximately ±15% and ±10% for natural PA6 and PA66 GF30, respectively. Finally, the Armstrong–Frederick model was used to carry out the simulations of the stress–strain response during the same variable load history. Comparison of the simulated and experimental results revealed that for both polymers, applicability of memory rules can be recognised.

Numerical investigation on the influence of fiber orientation mapping procedure to the mechanical response of short-fiber reinforced composites using Moldflow, Digimat and Ansys software

Within this paper, a numerical study was performed, aiming to assess the influence of fiber orientation on the mechanical properties of tensile specimens, by using the finite element method. The specimen, designed according to ISO-527-2, is type 1BA and consists of a reinforced polyamide with 30% glass fiber (PA66 GF30). The specimens were extracted from 2 mm thickness plates, for which the fiber orientation tensor was determined using the dedicated Moldflow software for injection molding. The composite material was modelled using Digimat mean-field homogenization tool. The mechanical evaluation was performed in Ansys finite element software by coupling it with Digimat and thus considering the anisotropic behavior of the material. Different mapping procedures and mesh sizes for the Moldflow model and Ansys model were considered.

Numerical analysis of chemically foamed thick-walled PA66 GF30 moldings

The paper presents a numerical analysis of thick-walled PA66 GF30 moldings with the addition of a chemical blowing agent with a content of 1-3 wt%, and the obtained results were compared with the real object. Computer simulations were performed using Moldex3D® software. Based on the numerical analysis, it was found that regardless of the dose of the blowing agent used, the largest pores were place in the core of the sample. Moreover, it was found that the size of the pores depends on their number in the cross-section of moldings. Compositions containing a higher cross-sectional pore density were characterized by smaller pore sizes. The results of the computer simulation also showed that increasing the blowing agent dose above 2 wt% does not significantly affect the size of the pores in the structure. The experimentally determined pore size of the composition containing 3 wt% chemical blowing agent slightly differs from the pore size obtained based on numerical analysis.

The Microcellular Structure of Injection Molded Thick-Walled Parts as Observed by In-Line Monitoring.

The aim of the study was to detect the influence of nitrogen pressure on the rheological properties and structure of PA66 GF30 thick-walled parts, produced by means of microcellular injection molding (MIM), using the MuCell® technology. The process was monitored in-line with pressure and temperature sensors assembled in the original injection mold. The measured data was subsequently used to evaluate rheological properties inside an 8.4 mm depth mold cavity. The analysis of the microcellular structure was related to the monitored in-line pressure and temperature changes during the injection process cycle. A four-times reduction of the maximum filling pressure in the mold cavity for MIM was found. At the same time, the holding pressure was taken over by expanding cells. The gradient effect of the cells distribution and the fiber arrangement in the flow direction were observed. A slight influence of nitrogen pressure on the cells size was found. Cells with a diameter lower than 20 µm dominate in the analyzed cases. An effect of reduction of the average cells size in the function of distance to the gate was observed. The creation of structure gradient and changes of cells dimensions were evaluated by SEM images and confirmed with the micro CT analysis.

Evaluation of Grinding of Unfilled and Glass Fiber Reinforced Polyamide 6,6.

This paper investigates the grinding process on unreinforced (PA66) and reinforced glass-fiber polyamide 6,6 (PA66 GF30) with Al2O3 and SiC abrasive wheels. Both materials were ground by varying rotations, workpiece infeed speed, depth of cuts for sequential roughing/finishing steps. Dry and liquid coolant conditions were also considered during the grinding process to evaluate the effects on part quality. The surface roughness was used to assess the quality of the final products with several parameter combinations, identifying the induced process trends. The results show that at the end of the finishing step, the surface roughness Rz was lower than 4 μm, attaining the lowest value of 1.34 μm for PA66 specimens. The analysis also suggested the choice of the Al2O3 grinding wheel to reach the lowest Rz values for both materials.

Experimental Study Regarding of Bending Behaviour of Stabilizator Link

Abstract This paper presents an experimental study of the behavior of anti-roll power link subjected to bending, power link coming from an Opel Astra G. The power link is made of PA66 GF30 polyamide. For this study, there were used a universal testing machine (Instron 5587) and a real-time strain measurement optical system (Aramis). The results showed are those obtained in the case of a compression force of 1,000 [N] namely: major Strain ε1, minor strain ε2, equivalent von Mises strain, displacement on X axis, displacement on Y axis (compression force direction), displacement on Z axis.

Prediction of Cutting Forces during Turning PA66 GF-30 Glass Fiber Reinforced Polyamide by Soft Computing Techniques

In the present paper the influence of the main cutting parameters on process performance during longitudinal turning of PA66 GF-30 Glass Fiber Reinforced Polyamide is investigated. The selected cutting parameters are cutting speed and feed-rate whilst depth of cut is kept constant. As outputs (responses), cutting force components Ft, FV and Fr were selected. Test specimens in the form of round bars and cemented carbide cutting tool were used during the experimental process. Fifteen experiments were conducted having all different combinations of cutting parameter values. Analysis of Variance (ANOVA), statistical approaches and soft computing techniques (artificial neural network) were applied in order to formulate stochastic models for relating the responses with main cutting parameters. The results obtained, indicate that the proposed soft computing techniques can be effectively used to predict the cutting force components (Ft, FV and Fr) thus; facilitating decision making during process planning since costly and time-consuming experimentation can be avoided.

Influence of the welding parameters on the structure and mechanical properties of vibration welded joints of dissimilar grades of nylons

Because of very attractive mechanical properties, nylons make interesting group of materials, used in many engineering applications. Vibration welding is a welding method used to join various kinds of thermoplastics. Almost 15% of all welds of thermoplastics are made with the use of vibration welding. The ability of vibration welding of different kind of polymers may present cost advantage over the other welding techniques and may allow to produce elements of lower weight and of a high quality. This work presents results of vibration welding of dissimilar materials joints made of nylon 66 (PA66) and 30% glass fibres nylon 66 (PA66 GF30). The aim of the studies was to determine the influence of the welding conditions on the quality of vibration welded joints. The quality assessment was done on the base of tensile tests and microscopy examination, conducted on light microscopy and scanning electron microscopy (SEM). Results of the tensile test indicate that it is possible to achieve good quality of joints at the proper welding conditions. The light microscopy examination showed that the welding parameters influence the orientation of the glass fibres in the weld zone, on the continuity of the material in the weld and on the thickness of the weld. The results of the SEM indicate that the vibration welded joint is formed as a result of joining of the matrixes of two welded nylons.

Surface roughness analysis in high-speed drilling of unreinforced and reinforced polyamides

In this work, surface roughness study in high-speed drilling of unreinforced polyamide (PA6) and reinforced polyamide with 30% of glass fibers (PA66 GF30) using cemented carbide (K20) tool has been carried out. The experiments were planned as per full factorial design of experiments. The effects of cutting speed and feed rate on centerline average surface roughness, maximum peak to valley height, and peak counts have been analyzed by developing response surface methodology based third-order mathematical models. The parametric analysis clearly indicates the influence of reinforced fiber on surface finish when high-speed cutting in drilling is used.

Machinability study in turning of unreinforced (PA6) and reinforced (PA66 GF30) polyamides with Polycrystalline Diamond (PCD) tools

This paper presents the application of Response Surface Methodology (RSM) to study the machinability aspects in turning of unreinforced (PA6) and reinforced (PA66 GF30) polyamides using Polycrystalline Diamond (PCD) tool. The non-linear mathematical models have been developed to study the effects of cutting speed and feed rate on machining force, cutting power and specific cutting force. The analysis reveals that machining force and cutting power increase with feed rate for PA6 and PA66 GF30. On the other hand, specific cutting force decreases with increase in feed rate for PA6, while it is minimal at 0.15 mm/rev for PA66 GF30 polyamides.

Machinability Study in MicroTurning of PA66 GF30 Polyamide with a PCD Tool

The polyamides have replaced many metallic materials due to excellent properties. The glass fibers are added to unreinforced polyamides to improve the mechanical as well as thermal properties. Even though the polyamides are produced as near net shapes, the machining has to be performed to meet the dimensional requirements and the assembly needs. The microturning is a conventional material removal process, which has been miniaturized. This study attempts to evaluate the micromachinability of reinforced polyamide with 30% of glass fibers (PA66 GF30) turning using a polycrystalline diamond (PCD) tool. The experiments were planned as per full factorial design of experiments (FFD). The effects of cutting speed and feed rate on cutting force, surface roughness, specific cutting force, and power were studied by developing second order mathematical models using response surface methodology (RSM). The parametric analysis reveals that cutting force, surface roughness, and power increase with feed rate, while specific cutting force decreases with increase in feed rate.

Modeling and Analysis of Machinability Characteristics in PA6 and PA66 GF30 Polyamides through Artificial Neural Network

The traditional metallic materials are replaced by some applications for turning process in PA6 and PA66 GF30 polyamides due to excellent properties such as high specific strength and stiffness, wear resistance, dimensional stability, low weight and directional properties. The addition of short fibers to the polyamides improves the properties over the unreinforced polyamides. As a result of these improved properties and potential applications in several fields of engineering, there is a need to understand the machining of unreinforced and reinforced polyamides. Selection of cutting tool and process parameters is important in machining of these composites. This article presents the application of artificial neural network (ANN) modeling to assess the machinability characteristics of unreinforced polyamide (PA6) and reinforced polyamide with 30% of glass fibers (PA66 GF30). The effects of process parameters such as work material, tool material, cutting speed, and feed rate on three aspects of machinability, namely, machining force, power, and specific cutting force have been analyzed through a multilayer feed forward ANN. The input—output patterns required for training are obtained through turning experiments planned as per full factorial design. The model analysis revealed that the minimum machining force results at low feed rate and independent of cutting speed, whereas the power is minimal when both the cutting speed and feed rate are at low levels for PA6 and PA66 GF30 polyamides machining irrespective of the cutting tool. On the other hand, the specific cutting force is minimal at low cutting speed and high feed rate in case of PA6 material, whereas high values of cutting speed and feed rate are essential for minimizing the specific cutting force for PA66 GF30 polyamide machining.

Study on Some Aspects of Machinability in Unreinforced and Reinforced Polyamides

The polyamides have replaced many traditional metallic materials due to excellent property profile. Even though polyamides are produced as near net shapes, machining has to be performed in the final stage of production. In this article an attempt was been made to study the effects of cutting speed and feed rate on machining force, cutting power, and specific cutting pressure during turning of PA6 and PA66 GF30 polyamides with K10 carbide tool. The response surface methodology (RSM) based parametric analysis reveals that machining force and cutting power increase with cutting conditions, while specific cutting pressure decreases with increase in feed rate.

Taguchi Approach for Achieving Better Machinability in Unreinforced and Reinforced Polyamides

Polyamide composites find wide applications in engineering fields due to favorable properties and hence replaced many traditional metallic materials. In order to increase the properties, the glass fibers are added to unreinforced polyamides. Even though polyamides are produced as near net shapes, machining is required to get the finished products. Thus, the selection of tool and cutting conditions is important in the machining of unreinforced and reinforced polyamides. This article presents the application of Taguchi's quality loss function approach, a multi-response optimization method, for achieving better machinability during turning of both unreinforced polyamide (PA6) and reinforced polyamide with 30% of glass fibers (PA66 GF30). The analysis of means (ANOM) and analysis of variance (ANOVA) on multi-response signal to noise (S/N) ratio are employed to determine the optimal parameter levels and to identify the level of importance of the parameters. The ANOVA results showed that the cutting speed is the most significant factor affecting machinability. Taguchi optimization results suggest that the optimal value of feed rate and cutting speed should be kept at a low level, whereas a polycrystalline diamond (PCD) tool is beneficial over cemented carbide (K10) for machining of both PA6 and PA66 GF30 polyamides to achieve better machinability.

Multi-parameter surface roughness analysis in turning of polyamide composite using Polycrystalline Diamond tool

This paper is aimed at studying the influence of the glass fibre reinforcement on the surface roughness under the cutting parameters prefixed. Experimental studies were carried out for composites PA 6 and PA 66-GF30 using Polycrystalline Diamond (PCD) tool. Surface roughness is represented by different profile amplitude parameters and proposed ratios. With appropriate cutting parameters, it is possible to obtain machined surfaces with <0.8 um of Ra. Consequently, it is possible to achieve surface qualities (dimensional precision) in composite workpiece of mechanic precision, IT 5 and 6.

Physical Cutting Model of Polyamide Composites (PA66 GF30)

Polymeric matrix composite materials presents advantages in a great number of applications due to their high specific strength and stiffness, wear resistance, dimensional stability, low weight and directional properties. As result of these properties and potentials applications exists a strong need to understand the manufacturing processes, particularly the machining process of these composite materials. This paper presents an investigation above the modelization of the cut, turning of small workpieces, on two materials: a polymer PA 6 (Polyamide) and a composite PA 66-GF30 (reinforced with 30% of glass fiber). The tests were carried out polycrystalline diamond tools (PCD). The objective of this experimental study is to evaluate the influence of the glass fiber reinforcement on the friction angle (ρ), shear angle (Φ), normal and shear stresses (σ, τ), chip deformation (ε) under the cutting parameters prefixed (cutting velocity and feed rate). The experimental model was compared with the theoretical model of Merchant.

A comparative evaluation of the turning of reinforced and unreinforced polyamide

This work presents an experimental study on the cutting process for polyamides PA 6 and PA 66-GF30 (reinforced with 30% glass fiber). The experiments were carried out on extruded workpieces using cemented carbide (K15) tools in turning. The objective of this study is to evaluate the influence of the glass fiber reinforcement on the chip compression ratio Rc, chip deformation a, friction angle ρ, shear angle Φ, normal stress σ, and shear stress τ under prefixed cutting parameters (cutting velocity and feed rate). The experimental physical model was compared with the Merchant equation.