Kamaljit Singh Boparai

Development of rapid tooling using fused deposition modeling: a review

Purpose The purpose of this study is to highlight the direct fabrication of rapid tooling (RT) with desired mechanical, tribological and thermal properties using fused deposition modelling (FDM) process. Further, the review paper demonstrated development procedure of alternative feedstock filament of low-cost composite material for FDM to extend the range of RT applications. Design/methodology/approach The alternative materials for FDM and their processing requirements for fabrication in filament form as reported by various researchers have been summarized. The literature demonstrates the role of various post-processing techniques on surface finish of FDM prints. Further, low-cost materials for feedstock filament have been investigated experimentally to check their adaptability/suitability for commercial FDM setup. The approach was to realize the requirements of FDM (melt flow rate, flexibility, stiffness, glass transition temperature and mechanical strength), necessary for the successful run of an alternative filament. The effect of constituents (additives, plasticizers, surfactants and fillers) in polymeric matrix on mechanical, tribological and thermal properties has been investigated. Findings It is possible to develop composite material feedstock as filament for commercial FDM setup without changing its hardware and software. Surface finish of the parts can further be improved by applying various post-processing techniques. Most of the composite parts have high mechanical strength, hardness, thermal stability, wear resistant and better bond formation than standard material parts. Research limitations/implications Future research may be focused on improving the surface quality of parts fabricated with composite feedstock, solving issues related to the uniform distribution of filled materials during the fabrication of feedstock filament which in turns further increases mechanical strength, high dimensional stability of composite filament and transferring the technology from laboratory scale to various industrial applications. Practical implications Potential applications of direct fabrication with RT includes rapid manufacturing (RM) of metal-filled parts and ceramic-filled parts (which have complex shape and cannot be rapidly made by any other manufacturing techniques) in the field of biomedical and dentistry. Originality/value This new manufacturing methodology is based on the proper selection and processing of various materials and additives to form high-performance, low-cost composite material feedstock filament (which fulfil the necessary requirements of FDM process). Finally, newly developed feedstock filament material has both quantitative and qualitative advantage in RT and RM applications as compared to standard material filament.

Experimental investigations for development of Nylon6-Al-Al2O3 alternative FDM filament

Purpose The purpose of this paper is to fabricate Nylon6-Al-Al2O3-based alternative fused deposition modeling process (FDM) feedstock filament in place of commercial acrylonitrile butadiene styrene (ABS) filament (having required rheological and mechanical properties) for rapid manufacturing (RM) and rapid tooling (RT) applications. The detailed steps for fabrication of alternative FDM feedstock filament (as per field application) with relatively low manufacturing cost and tailor-made properties have been highlighted. Design/methodology/approach The rheological and mechanical suitability of nylon6-Al-Al2O3 feedstock filament has been investigated experimentally. The approach is to predict and incorporate essential properties such as flow rate, flexibility, stiffness and mechanical strength at processing conditions and compared with commercial ABS material. The proportions of various constituents have been varied to modify and improve rheological behavior and mechanical properties of alternative FDM feedstock filament. Findings The alternative material of feed stock filament was successfully developed and loaded in commercial FDM setup without changing any hardware and software. The result of study suggests that the newly developed composite material filament has relatively poor mechanical properties but have highly thermal stability and wear resistant as compared to ABS filament and hence can be used for tailor-made applications. Research limitations/implications In this work, no additive was added for improving the bond formation of metal and polymeric materials. The newly developed filament was prepared on single screw extruder. For more uniform mixing of metal and polymeric materials, further studies may be conducted on twin screw extruder. Also, for the present research work, the testing of newly developed filament has been limited up to mechanical testing, which may be extended to chemical and thermal analysis to understand thermal stability and degradation mechanism of newly developed composite material. Practical implications The proportion of filler material (Al-Al2O3) in Nylon6 matrix was set as a constraint, which was adjusted based upon melt flow index of original equipment manufacturer developed material (ABS), and temperature conditions were available at FDM nozzle (so that hardware and software system of commercial FDM setup need not to be altered). Originality/value The present approach outlined selection, processing, fabrication and testing procedure for alternate feedstock filament, which fulfills the necessary requirements of FDM process and has been customized for RT and RM applications. This work highlights mechanical strength evaluation of feedstock filament (which is necessary before the loading of material in FDM system). The potential applications of this investigation include RM of functional parts, tailor-made grinding tools for dentists and RT of metal matrix composite having complex geometry.

Comparison of tribological behaviour for Nylon6-Al-Al2O3 and ABS parts fabricated by fused deposition modelling

In the present work, a comparison of the tribological properties of Nylon6-Al-Al2O3 and ABS parts fabricated using the fused deposition modelling (FDM) method is made. Under dry sliding conditions at room temperature, the sliding wear behaviour of FDM-built parts with three different proportions of Al and Al2O3 was investigated. Loads of 5, 10, 15 and 20 were applied at a sliding velocity of 1.36 m/s for durations of 5 and 10 minutes. The results show that all FDM-built Nylon6-Al-Al2O3 components have better wear resistance as compared to their FDM-built ABS counterparts. Further, the influences of filler materials on various wear mechanisms such as adhesion, abrasion, etc. are identified. It was also observed that the composite materials prepared with different proportions are more wear resistant, having less friction coefficients and friction force than the commercially used ABS material for FDM components.

Wear behavior of FDM parts fabricated by composite material feed stock filament

Purpose In this study the friction and wear behavior of fused deposition modeling (FDM) parts fabricated with composite material and acrylonitrile butadiene styrene (ABS) material feedstock filament were realized and compared under dry sliding conditions. Design/methodology/approach The tests were performed by applying the load of 5, 10, 15 and 20 N with sliding velocity of 0.63 m/s for the duration of 5 and 10 min at room temperature. Findings The results highlight various wear mechanisms such as adhesion, abrasion and fatigue during the investigation. It was observed that the wear volume, friction force, friction co-efficient and temperature were sensitive to the applied load and time duration. The composite material showed a remarkable improvement in wear properties as compared to the ABS material. Research limitations/implications The investigations reported in the present research work is based on comparative analysis (of composite material and ABS material feedstock filament). The results may be different in practical applications because of different operating conditions. Practical implications The parts fabricated with proposed composite material feedstock filament are highly wear resistant than basic ABS filament. This may lead to the development of better wear resistance components for numerous field applications. Originality/value The potential of this research work is to fabricate FDM parts with composite material feedstock filament to cater need of wear resistant industrial components.

Experimental Investigations for Statistically Controlled Vacuum Moulding Solutions of Al-SiC MMC

The purpose of the present investigations is to study the effect of vacuum moulding (VM) process parameters (namely: chemical composition, component volume and vacuum pressure) for development of statistically controlled Al-SiC MMC. Starting from the identification of component/ benchmark, technological prototypes were prepared by VM process for functional validation of the parts. The study suggested the long-term performance level of the VM process after it has been brought under statistical control as casting solution for Al-SiC MMC. The provided data from the experimentation highlights the ability of the VM process to produce a product that will consistently meet the design requirements and the customer expectation.

Thermal and surface characterization of ABS replicas made by FDM for rapid tooling applications

This paper aims to focus on the changes in thermal and surface characteristics of acrylonitrile butadiene styrene (ABS) material when exposed to chemical vapours for surface finishing. The poor surface finish and the dimensional accuracy of the fused deposition modelling parts (of ABS material) because of the stair-stepping hinder their use for rapid tooling applications, which can be improved by vapour finishing process. The differential scanning calorimetry (DSC) tests are performed to investigate the thermal behaviour of ABS thermoplastic after vapour finishing.,The hip prosthesis replica has been used to highlight the efficacy of chemical finishing process for intricate and complex geometries. The replicas are treated with chemical vapours for different durations. The DSC tests are performed along with surface roughness, surface hardness and dimensional measurements of exposed replicas and compared with unexposed replica.,The longer finishing time, i.e. 20 s, manifested higher melting peak temperature, higher melting enthalpy and higher heat capacity along with smoother and harder surface as compared with unexposed replica. The finishing process enhanced the bonding strength and the heat-bearing capacity of ABS material. The vapour finishing process enhanced the thermal stability of the material which may extend its sustainability at higher temperatures.,The improved thermal stability of ABS thermoplastic after chemical vapour finishing has been demonstrated. This advancement allows the use of ABS in functional tooling suitable for small production runs with higher flexibility and lead time savings.,The heat effects associated with phase transitions as a function of temperature are studied in case of replicas finished with chemical vapours. The relationship between melting enthalpy and surface characteristics has been ascertained.

Process optimization of single screw extruder for development of Nylon 6-Al-Al2O3 alternative FDM filament

Purpose The purpose of this study is to investigate the process parameters of a single-screw extruder for development of Nylon6-Al-Al2O3-based alternative fused deposition modeling process (FDM) feedstock filament (in lieu of commercial acrylonitrile butadiene styrene filament). The effect of major screw extruder parameters on the tensile strength of fabricated filaments has also been analyzed. Design/methodology/approach The Taguchi experimental log has been designed for investigating the significance of input parameters of screw extruders (such as mean barrel temperature, die temperature, screw speed, material composition and speed of take up unit) on the tensile strength of fabricated filaments. The suitability of alternative material as an FDM filament has been verified by rheological investigations. The tensile strength of an alternative feedstock filament has been investigated experimentally according to the ASTM-638 standard. The analysis was performed by the analysis of variance (ANOVA) method with the help of MINITAB 17 software. The stiffness of the FDM printed parts with nine different feedstock filaments (prepared by selecting nine different combinations of analytical parameters) was determined by dynamic mechanical analysis (DMA). Findings The tensile strength of the feedstock filament was significantly affected by the variation of major input parameters during the processing of alternative material on a single-screw extruder. The ANOVA shows that two process parameters (namely, material composition and die temperature) were significant at the 5 per cent level (“F” value 41 and 21.96, respectively) and remaining two (mean barrel temperature and screw speed) were insignificant at the 5 per cent level. Further, a linear regression model has been developed to predict the tensile strength of the alternative feedstock FDM filament. The results highlight that a deviation of <1 per cent was observed (in the tensile strength of nine sets of experimental runs) as compared to the predicted values of the regression model. In addition to above, the DMA result also indicates that the filament fabricated with optimum combination of parameters has highest stiffness and is more suitable for the FDM system. Research limitations/implications During the processing of alternative material in a single-screw extruder and FDM system, the increase of filler contents adversely affects the contact surfaces. Practical implications The FDM parts with customized properties (viz., thermal and tribological) can be fabricated with alternative feedstock filament material. Originality/value The potential to consider alternative filament material for FDM system includes rapid manufacturing of functional parts, tailor-made grinding tools for dentists and rapid tooling of metal matrix composites having complex geometry.

Development of Rapid Tooling Using Fused Deposition Modeling

This chapter highlights the in house development of low cost alternative FDM feedstock filament with tailor made properties. The experimental study was performed to fabricate (Nylon6-Al-Al2O3 based) alternative fused deposition modeling (FDM) feedstock filament in place of commercial acrylonitrile butadiene styrene (ABS) filament (having specific rheological and mechanical properties) for rapid manufacturing (RM) and rapid tooling (RT) applications. The detailed steps for fabrication of alternative FDM feedstock filament (as per field application) with relatively low manufacturing cost and tailor made properties have been highlighted. The rheological and mechanical suitability of Nylon6-Al-Al2O3 feedstock filament has been verified experimentally. The approach is to predict and incorporate essential properties such as flow rate, flexibility, stiffness, and mechanical strength at processing conditions and compared with commercial ABS material. The proportions of various constituents have been varied in order to modify and improve rheological behavior and mechanical properties of alternative FDM feedstock filament. The developed feed stock filament was loaded in commercial FDM setup without any change in hardware and software. The results of study suggest that the newly developed composite material filament has relatively poor mechanical properties but have high thermal stability and wear resistant as compared to ABS filament and hence can be used for tailor made applications.

Effect of Process Parameters of Fused Deposition Modeling and Vapour Smoothing on Surface Properties of ABS Replicas for Biomedical Applications

In spite of numerous applications, the functionality of FDM patterns is severely influenced by poor surface finish which must be maintained as it would be further inherited by castings. The impact of process parameters of an advanced finishing technique i.e. Vapour Smoothing (VS) has been investigated on surface roughness, hardness and dimensional accuracy of hip implant replicas. The Taguchi L18 Orthogonal Array and ANOVA statistical tools were used to scrutinize the significant parameters. The exposure of hot chemical vapours tends to melt the upper surface of ABS parts which are immediately cooled. This led to improvement in surface finish and surface hardness as layers settle down as smooth surface. The shrinkage in FDM parts has been noticed due to layer re-settlement. Based on significant parameters, the mathematical models for each response were formulated using Buckingham Pi theorem. The multi-response optimization study was performed to endorse a single set of process parameters to attain best surface characteristics. The Differential Scanning Calorimetry tests were performed which reveal that VS process enhanced thermal stability of material due to increase in bonding strength.