Search

High-density polyethylene is a high-strength, and low-weight material system. Besides numerous applications in a variety of fields and products, its machining for generation of holes is rather difficult with traditional methods such as drilling as the process is not very conducive for composites due to associated damage. Hence, a non-contact material removal process such as laser machining provides an appealing, cost-effective, accurate, and fast alternative. For this study, the effect of the laser process controls key parameters such as laser power and laser speed on the cut surface integrity defined by surface roughness, kerf taper angle, and heat-affected zone of neat HDPE and HDPE with 60 wt% cenosphere was investigated and optimized using response surface meth-odology. Also, the machining operation was visualized using a Photron FASTCAM SA 1.1 high-speed camera to observe the effects of the high-intensity laser beam on specimens and to investigate the mechanism of laser machining. The optimum values for a defect-free cut surface (minimum surface roughness and low kerf taper angle) in neat HDPE comes out to be as laser power of 97.5 W and laser speed of 5 mm/s, with corresponding surface roughness and kerf taper angle of 54.304 mu m and 0.152 degrees respectively and the optimum input values for HDPE with 60 wt% cenosphere are 102.126 W laser power and 5 mm/s laser speed, with corre-sponding surface roughness and kerf taper angle of 26.574 mu m and 0.253 degrees. This study finds importance for the industrial and medical application to creates small size holes for mechanical joints such as rivets, bolts, and screws in assembly as low surface roughness and kerf width are always preferred as quality parameters in creating holes for industrial applications.

This work is focused on the comparative study of in-situ processing temperature measurement during microwave-assisted compression molding (MACM) and conventionally compression molding (CCM) of fiber-reinforced thermoplastic matrix composite (FRTMC). In the present study, Kenaf reinforced high density polyethylene (HDPE) composite (volume fraction 20%) was chosen as the FRTMC. The processing temperature of the FRTMC was selected as per melting peak obtained from differential scanning calorimeter (DSC). The degradation temperature of FRTMC was obtained using thermogravimetric analysis (TGA). The fabrication time using MACM was found to be 84% less compared to CCM. In the MACM, temperature variation towards width and depth of specimen was found to be negligible. The thermal contours were used to observe temperature profiles during composite fabrication using CCM and MACM. Furthermore, the mechanical response of the MACM fabricated composite was better compared to CCM composite.

This work aims to implement an efficient and accurate computational model to predict elastoplastic properties of UHMWPE/nano-HA bio-composite. Mean-field (MF) homogenization and finite element (FE) techniques are implemented to predict the elastoplastic behavior of composite. The predicted results obtained by MF and FE were compared and validated experimentally by fabricating the specimen using microwave-assisted compression molding. The axial and transverse moduli were increased by 49% at a 20% weight fraction of nano-HA. The hardening modulus was also found to be increased by 67%. Further, Degree of crystallinity (Xc) of fabricated composite specimens was determined using differential scanning calorimetry analysis. It was found that the Xc increased 34% with the addition of 20% weight fraction of nano-HA. In vitro, direct contact cytotoxicity and antibacterial test were performed to determine cell adhesion and bacterial behavior of the composite.

The present work deals with the crashworthiness behaviour of high-density polyethylene (HDPE) composite against aluminium alloy (Al5022). For the composite reinforcement purpose, 20 wt. % of kenaf ...

In the present study, a series of Ni + xCr7C3 (x is the weight fraction of the Cr7C3) clads on hydro turbine steel (CA6NM) were developed through microwave cladding. The weight fraction of Cr7C3 wa...

Ultra-high molecular weight polyethylene (UHMWPE) and CoCr alloy are popular tribo-pair in total knee replacement. Wear in the liner is a major failure reason for knee implant. Therefore, this work focuses on an approach for reducing the wear rate by irradiating the UHMWPE specimens using Ultraviolet (UV) radiation. The powder of UHMWPE was molded into a plate by microwave-assisted compression (MAC) molding. The UV radiations of intensity 0.025 J/cm

For light weight and high strength applications, different types of fibers such as carbon fiber (CF), glass fiber (GF) and Kevlar fibers are stacked layer by layer to fabricate low density laminates. This process is known as hybridization and fabricated composites are called hybrid composites. These types of composites used in high structural applications. Hybrid composites are known for their high strength to weight ration and ability to absorb energy. In present work, Izod impact and shore-D hardness response of hybrid composites (GF and CF reinforced polymer matrix) were investigated. Hybrid composites with different stacking sequence of CF and GF were fabricated by vacuum assisted resin infusion microwave curing (VARIMC) process. Bidirectional woven fabrics of CF and GF was used. Three types of stacking sequence (CGCGCGC)3, (C2G3C2)3 and (GC2GC2G)3 was used for hybrid composites. According to ASTM standard for testing, the thickness of the laminates was maintained about 6 mm. Results revealed that the variation of impact strength was strongly depends on lay-up stacking sequence of GFs and CFs in hybrid composite laminates. Three modes of failure of laminates i.e., matrix cracking, fiber breakage and delamination were observed.

With the growing energy need, hydro power becomes the most outstanding source of renewable, clean and affordable energy. However, slurry erosion of underwater components reduce the overall efficiency of the power generating system, thus, fails to fulfil energy goals entirely. To prevent erosion damage, protective coatings are highly recommended. In present study, response of microwave cladding against slurry erosion wear is reviewed. The effects of process parameters such as microwave power and exposure time are discussed in detail. Microwave cladding of different material systems and their slurry erosion performance are also summarized.

This study focused on the development of microwave composite cladding of a Ni-based alloy reinforced with varying proportions (wt.%) of B4C such as 0, 5, 10 and 20% on a SS-304 steel substrate. Clads showed metallurgical bonding with the substrate by the partial dilution of the materials. Various techniques of characterization confirmed the formation of hard phases of borides and carbides such as Fe23B6, Fe5C2, Cr7C3, Cr7BC4 and their distribution in the Ni matrix throughout the clad volume. Flexural performance tests of the clads were done using a three-point bend test at a deformation rate of 0.5 mm/min, and composite clad reinforced with 10% B4C showed the highest flexural strength that was observed to be 479 ± 13 MPa. Clads failed in the upper transition load, and a sudden load drop was observed at the failure points of the clads. Fractography revealed that reinforced phases provided sufficient strength to the Ni-based ductile matrix because crack propagation in the clads was arrested by these hard phases while deformation.

Woven fabric reinforced epoxy composite shown inherent favorable characteristics for aerospace industry applications. This paper comprehensively investigated the mechanical and fracture behavior of unidirectional carbon woven fabric reinforced epoxy composite using experimental and computational techniques. The composites were fabricated with two, four, and six ply laminates with cross-ply and inclined ply (45/–45) orientations. Laminates were fabricated using Vacuum-Assisted Resin Infusion Microwave Curing technique with a high fiber volume fraction of 50% for each laminate. Experimental analyses were performed to predict the behavior of composites under tensile, shear, and impact loading environment. Further, the mean-field homogenization technique coupled with the finite element method was employed to predict orthotropic material properties, fracture energy, and fracture parameters ( KIC and GIC) of the composite. The results showed that fracture energy obtained by the computational technique was in good agreement with experimental results. The values of GIC increased with the number of plies both for cross and inclined plies orientation composites. KIC values were higher for cross plies laminates than the inclined plies laminates.

Kevlar®-reinforced composites are used in high energy absorption applications. In the present work, Kevlar®-reinforced ultra-high molecular weight polyethylene composites were fabricated through microwave-assisted compression molding. The microwave-assisted compression molding parameters were optimized through trial and error method. Analysis of mechanical behavior of composites was accessed through uniaxial tensile testing, flexural testing, impact testing, and nano-indentation. The fractured specimens were observed using scanning electron microscopy. An increment of 92.2% was observed in the ultimate tensile strength of the ultra-high molecular weight polyethylene/Kevlar® composite compared to neat ultra-high molecular weight polyethylene. Flexural properties, impact energy absorption rate, and hardness property of the composite were increased by 27.1%, 91.6%, and 4.77%, respectively, compared to pure ultra-high molecular weight polyethylene. Enhanced mechanical properties may be attributed to unique microwave heating phenomena during microwave-assisted compression molding.

In this paper, we present the development of micrometric and nanometric Ni + 10% Cr7C3 composite clad on ASTM A743 grade CA6NM hydroturbine steel through microwave irradiation. The microstructure of micrometric clad exhibited blade and rod-like structure of carbides embedded in [Formula: see text](Ni, Fe) solid solution, while nanometric clad leads to the evolution of petal-like structure of carbides. The developed nanometric clad shows uniform microstructural features with a low level of carbide decomposition. As a result, the average nanohardness and fracture toughness of nanometric clad improved by 38.11% and 8%, respectively, compared to the micrometric clad. Clads have porosity of the order of 1.1% and 0.81% for micrometric and nanometric clad, respectively.

Microwave cladding is an emerging surface modification technique. Temperature control is the key issue in any surface modification technique. In microwave cladding, non-contact temperature measurement methods are widely used; however, these methods report only the surface temperature of the susceptor. In the present study, a modified B-type thermocouple was used to measure the real time-temperature distribution while developing Ni-based clad. Formation of clad has been discussed with respect of time-temperature distribution. Effect of microwave power on heating profile was also investigated.

Machining of microwave processed nano-Hydroxyapatite (HA) reinforced ultra-high molecular weight polyethylene (UHMWPE) is challenging due to enhanced mechanical strength. The present research work aims to find possibility of machining on microwave processed UHMWPE/nano-HA composite using laser beam machining (LBM) method. The weight fractions of nano-HA in UHMWPE were 10%, 15% and 20%. The surface roughness of UHMWPE increased 3.64 times with 20% nano-HA addition. The heat-affected zone (HAZ) and defect factor decreased 64.32% and 35.75%, respectively with 20% nano-HA addition.

Carbon fiber reinforced epoxy composite (CFREC) have gained interest due to their high strength to weight ratios. Conventional techniques to fabricate carbon fiber composite come with a limitation of overheating, high cycle time and high cost. The present manuscript is focused to address some manufacturing challenges during microwave curing of CFREC with 10% reinforcement by weight. In the present work microwave curing was done with or without assistance of vacuum pressure. The mechanical behavior of the specimens was studied in terms of tensile strength and hardness. The scanning electron microscopy (SEM) was used to analyze the tensile fractured specimens.

In this research work, multi-layered composites of pure and hybrid woven fibre mats were fabricated using microwave-assisted compression moulding process. The hybrid composite consisted of jute and kenaf fibre as reinforcement having weight fraction of 29 ± 1%, while high-density polyethylene acted as the matrix. The laminate of multi-layered composites was fabricated by stacking the kenaf and jute woven fibre mats with high-density polyethylene matrix, resulting in different hybrid composites, i.e. JJJ, KKK, JKJ and KJK. JKJ exhibited maximum flexural strength of 55.64 ± 2.8 MPa, whereas KJK exhibited maximum flexural modulus of 3.65 ± 0.2 GPa. The tensile strength, impact strength and Shore D hardness were maximum in case of KKK composite, having the value of 60 ± 3 MPa, 31.8 ± 1.6 kJ/m2 and 58 ± 2.9, respectively. It can be concluded that the stacking sequence has a nominal effect on flexural strength, tensile strength and impact strength of the composites.

The present work focused on the investigation of hole quality characteristics in laser-drilled kenaf/high-density polyethylene (HDPE) composites. Microwave-assisted compression molding was used to fabricate kenaf/HDPE composite with 20 wt% of the kenaf fiber reinforcement. The two input parameters pertaining to the experimentation were laser power and cutting speed. Kerf taper angle, heat-affected zone (HAZ), and surface roughness were investigated to evaluate the surface quality and accuracy of the holes generated through laser drilling on composite specimens. The assessment of HAZ was performed qualitatively through image analysis on scanning electron micrographs. Additionally, the effect of composite thickness on laser drilling was also investigated for 3-, 6.7-, and 10-mm composite specimens. The central composite design was used to plan the experiments. The kenaf/HDPE composite drilled at power 120 W and speed 2 mm/s shows a minimum kerf taper angle and surface roughness of 0.056° and 3.83 ± 0.19 µm, respectively. Regression model was obtained for the establishment of relation between input variable parameters and responses. Experimental results and predicted model results exhibited good agreement with each other as they provide error less than 5.35%. The analysis of variance was carried out to obtain the significance of the model chosen for optimization of the output values, that is, surface roughness and kerf taper.

In this work, carbon fibre composites were manufactured using vacuum-assisted resin infusion microwave curing and vacuum-assisted resin infusion thermal curing processes. The microwave curing as well as thermal curing heat generation mechanisms were studied along with the thickness of the carbon fibre composites. Microwave power levels of 180 W, 360 W, 540 W and 720 W and thermal power levels of 1000 W and 2000 W were used. The K-type thermocouples were placed between the layers of the carbon fibres to record temperature profile during the curing process. The role of power levels was studied on thermal gradient along with the thickness of composites, which influences the curing kinetics. The composites were evaluated for their degree of cure, density and void percentage. Mechanical performance of the composites was assessed in terms of uniaxial tensile test, three-point bend test and interlaminar shear strength test. It was observed that microwave-cured composites were manufactured with less time and energy compared to thermal curing. The mechanical performance of microwave-cured composites was also better than thermally cured composites.

Present work explores the utilization of forest waste (pine cone) and plastic waste (recycled HDPE) to fabricate wood plastic composites (WPCs) using microwave-assisted compression molding. The developed WPCs were experimentally subjected to physical, thermal, and mechanical characterization. Physical properties deteriorated when the filler loading level was maximized over the weight percentages due to poor wettability. The thermal study revealed that the melting point of the composites was influenced by filler weight percentage. The composites reinforced with 20 Wt.% filler exhibited the highest tensile, flexural, and impact strength of 20.01 MPa, 20.98 MPa, and 15.79 kJ/m2, respectively. Scanning electron microscope (SEM) micrographs revealed voids, microcracks, and poor filler dispersion were dominantly responsible for composites failure with increased filler weight fraction.

Present work deals with the nonlinear finite element analyses of ultra-high molecular weight polyethylene (UHMWPE). UHMWPE has been presented for ballistic design investigation of lightweight body armour using ANSYS-Workbench. The ballistic performance of UHMWPE has been compared with Kevlar/epoxy composite and alumina. The study is presented in terms of the ballistic limit of UHMWPE, Kevlar/epoxy, and alumina plate, the implication of obliquity (at 30°, 45°, and 60°), projectile shape (elliptical, conical, and spherical shape). The sequencing order of material layup for a bi-layer composite and ballistic performance of single-layered UHMWPE has been compared with the multi-layered plate. The parametric studies have been presented in the form of residual velocity, the ratio of energy transferred to impact velocity of the ballistic plate, and perforation rate for the single and multi-layered UHMWPE. The results of the numerical analyses of UHMWPE have been compared with the Kevlar/epoxy composite. It has been found that the armour system made of UHMWPE laminate composite resulted in a 40.6% weight reduction compared to Kevlar/epoxy configuration with a 17.3% higher ballistic limit.

This research work is aimed to utilize microwave energy for rapid fabrication of nano-hydroxyapatite (nHA) reinforced polycaprolactone (PCL) composite foam. Weight fraction of nHA and NaCl was fixed at 20% and 30%, by weight, respectively. The NaCl was acts as microwave absorber as well as the porogen agent in the composite. The interconnected porosity was induced by leaching of the NaCl particles from composite in an ultrasonicator bath. The influence of microwave process parameters such as microwave power and exposure time was studied on mechanical and microstructural feature of PCL/nHA composite foam.

The present investigation is based on fabrication of sisal reinforced high density poly ethylene (HDPE) composites using a novel manufacturing route of microwave processing. Microwave processing was carried out in a multimode applicator at 2.45 GHz with single and multi-layered sisal fibre reinforcement. The comparison between single and multilayered sisal fibre reinforced composites were assessed in terms of tensile, flexural and impact strength. It was found that the multi-layered sisal fibre microwave processed composite has superior properties than single layered reinforced composite. The fractography of tensile fractured surfaces was assessed using electron microscopy. The microwave processed HDPE/sisal composites can be used as a dashboard material of an automobile.

The present work deals with the microwave-assisted compression moulding of high-density polyethylene (HDPE)-based composites. In the present work, 20 wt% of reinforcement in the form of kenaf and multi-walled carbon nanotube (MWCNT) was used to fabricate HDPE/kenaf and HDPE/MWCNT polymer composites. The mechanical characterizations of the microwave-processed composites were carried out in terms of uniaxial tensile test with different strain rate, multistep stress relaxation, flexural and impact test. The uniaxial tensile test revealed that the tensile modulus of microwave-processed four-layered HDPE/kenaf polymer composite was 35.2% higher than that of HDPE/MWCNT polymer composite. The HDPE/MWCNT polymer composite showed a minimum of 1.25 GPa and a maximum of 4.7 GPa of elastic modulus when tested at different strain rate. The impact energy absorbed by the HDPE/kenaf polymer composite (1.055 J) was 81.12% higher than the HDPE/MWCNT polymer composite (0.582 J).

Poly-L-lactide (PLLA) reinforced with nano-hydroxyapatite (HA) foams were fabricated using a novel method of microwave-assisted compression moulding. The microwave-assisted compression moulding is ...

The phenomenon of slurry erosion in hydro turbines and its components is a major challenge. Microwave cladding is a potential surface modification technique to mitigate the effects of slurry erosion. Microwave exposure time during cladding could play an important role on the microstructure and performance of the developed clads. In the present work, Ni + 20 wt% Cr7C3 composite clads were developed on CA6NM hydro turbine steel using microwave cladding technique. The effect of microwave exposure time on clad microstructure and its subsequent effect on slurry erosion characteristics were studied. The developed clads were assessed in terms of their microstructure, phase analysis, nanohardness and fracture toughness using various techniques. Slurry erosion characteristics of the developed clad were studied using a slurry jet erosion test rig. The slurry erosion trials were performed at a jet velocity of 40 m/s with an impact angle of 90° for 120 min. Cumulative weight loss, wear rate and wear mechanisms were assessed to determine the slurry erosion performance of the developed clads.

In the present work, bi-layer Alloy-718/NiCrAlY was deposited on grey cast iron substrate by using high velocity oxy-fuel (HVOF) thermal spray coating process. The deposited coating was subjected to microstructure studies, microhardness, high-temperature oxidation and erosion test. The average microhardness of the Alloy-718 coating was found to be 563 ± 15 HV0.2, which is about 2.5 times higher than that of the substrate. The oxidation test was carried out at 900 °C for 50 cycles in a laboratory tube furnace. The one oxidation cycle was comprised of 1 h heating at 900 °C followed by cooling of 20 min in ambient air. The erosion behaviour of the coated and uncoated specimens was investigated at 800 °C using a high temperature air-jet erosion test rig, at impact angles of 30° and 90°, respectively. The mechanism of material removal in the eroded samples was determined by using scanning electron microscopy images of the eroded surfaces. The test results revealed that the Alloy-718 coating offered superior protection to the grey cast iron substrate from oxidation and erosive wear at high temperature. The increased oxidation resistance can be attributed to the formation of favourable oxides such as Cr2O3, Al2O3, and TiO2 in the coating. The microcutting and the formation of craters caused by the repetitive impacts of erodent particles were identified as the mechanisms of material loss from the surface of coating during the erosion testing conducted at 30° and 90° impact angles. The higher hardness along with the formation of Cr2O3 and Al2O3 as stable oxides have contributed in the enhanced erosion performance of the bi-layer Alloy-718/NiCrAlY coating as compared to the substrate.

Metal matrix composite (MMC) clads were developed through microwave cladding technique on CA6NM substrate using different microwave power levels. The influence of microwave power was investigated on the microstructure, phase evolution, mechanical properties, and erosion-tribo performance of the clad layers. Increase in microwave power resulted in reduction of Cr7C3 phase in clad layers, which eventually decreases the fracture toughness and microhardness of the clad. Clad fabricated at 600 W exhibited highest fracture toughness (11.6 ± 0.58 MPa√m) and microhardness (949 ± 47.45 HV). All clads exhibited highest erosion at 60 deg indicating a mixed erosion mode. Clads fabricated at power levels beyond 600 W, with less Cr7C3 content exhibited severe carbide pullout, thus deteriorated the slurry erosion resistance of the clads.

Tool wear and subsequent tool failures are essential issues in manufacturing, where tool failures may need future planning of tool’s inventory. A Tool Condition Monitoring System (TCMS) that predicts the tool’s life ahead of time could help better inform inventory operations regarding the stocking of tools. However, TCMSs for drilling tools that are based upon statistical models have been less explored. The primary objective of this paper was to explore predictive TCMSs for drilling operations that are dependent upon statistical models like SARIMA and ETS. Drilling tools each of diameters 4.76 and 6.35 mm were used to drill holes of 10 mm depth at two different spindle speeds (750 and 1100 rpm). Data were recorded in real time using an open-source microcontroller and accelerometer. Data included the time required to drill, peak work (time x maximum instantaneous power during a drill), tangential acceleration, and acceleration vibration. Once data regarding these parameters were collected, SARIMA and ETS models were calibrated to these data. For calibration, each of the parameters above was treated as a time series, where 67% of data were used for model training and 33% of data were used for model testing. Results revealed that the SARIMA model showed better performance (smaller error) in predicting different parameters compared to the ETS model. We discuss the implications of using statistical models in TCMSs for drilling and other manufacturing operations.

The present work aims to study the abrasive wear of kenaf/high-density polyethylene (HDPE) composites with 20% weight fraction reinforcement of the kenaf fiber. A unique technique of the microwave-assisted compression molding (MACM) was used to fabricate the composites. The pin-on-disc setup was used for two-body abrasive wear, in which the kenaf/HDPE composite acts as a pin and the abrasive paper (P100) acts as a counter surface. Two-body abrasive wear tests were conducted for HDPE and kenaf/HDPE composites at normal loads of 10 N, 20 N, and 30 N and the sliding speed of 1 m/s, 2 m/s, and 3 m/s within 100 m of sliding distance. Tribofilm formation was observed at higher values of load and speed, which helps in reducing the wear-rate of the composites. Wear mechanism of the kenaf/HDPE composite is discussed in detail and supported with scanning electron microscope (SEM) fractography.

Carbon nanotubes have been used as reinforcements in polymers due to their high elasticity, flexibility, and thermal conductivity. In this study, pellets of high-density polyethylene +20 wt% carbon nanotube and polypropylene +20 wt% carbon nanotube were cured using microwave energy. X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, uniaxial tensile test, and scanning electron microscopy was used to study morphology, thermal stability, and mechanical performance of the microwave-cured composites. X-ray diffraction analysis confirmed the bonding between the polymer and carbon nanotube as the peaks shifted and intensified. From the thermal study, it was observed that melting point of the composites is affected by microwave curing and the crystallinity of high-density polyethylene/carbon nanotube and polypropylene/carbon nanotube changed by 57.67% and 47.28%, respectively. Results of the uniaxial tensile test indicated that Young’s modulus of microwave cured high-density polyethylene/carbon nanotube and polypropylene/carbon nanotube composites were improved by 295% and 787.8%, respectively. Scanning electron microscopic fractography shows the stretching of polymer over-lapped on carbon nanotubes in the direction of the applied load.

Porous bio-composites made of Poly (L- lactide) (PLLA) and nano-hydroxyapatite (HA) are widely used in bone tissue engineering applications owing to their human bone mimicking properties. In this work, a novel method to fabricate porous PLLA/HA bio-composite scaffolds using microwave energy was explored. Microwave curing is a novel processing route of polymer-based composites, owing to its faster and uniform heating, better temperature control, which yields improved mechanical properties. The porosity in the PLLA/HA bio-composites was introduced through selective leaching methods. The developed scaffolds were characterized for the porosity using SEM. The porous scaffolds were observed to have a homogeneously interconnected porous structure with narrower pore size distribution. The theoretical porosity percentage was obtained in the range of 21% -23% where actual porosity percentage was in the range of 20-22 %. The porosity connectivity was comparable and having the value of 96.67%. The mechanical properties were also characterised in term of compression and flexural strength. The compression strength for PLLA+ 10% HA (11.17 MPa) was greater than neat PLLA, whereas the flexural strength was greater in case of neat PLLA (95.4 MPa).

Composite materials are widely used in the engineering field due to their high strength-to-weight ratio which offers enhanced mechanical behaviour of the components. Some of the widely used fields for the composite materials are body armors, safety shoes, sports and in many other regions. In this paper ballistic impact simulation of composite plate of Ultra high molecular weight polyethylene (UHMWPE) and alumina is done using ANSYS-AUTOYN 16.0. For analysing the behaviour of the composite plate the impact velocity is varied in steps and is directed perpendicularly on to the surface of the plate. Here three cases have been studied, in the first case UHMWPE as front plate of UHMWPE/Alumina composite has been considered for the impact whereas in second case alumina is used as the front plate of the impact and in the third case UHMWPE is alone used as the impact plate.