Gear Manufacturing Research Articles

Investigation on Fabrication of SS316 Gear by Wire-EDM

Manufacturing of miniature gears with good accuracy and quality, and at low cost is a challenging task for traditional manufacturing processes. Wire-cut electric discharge machining (WEDM) has the capacity to machine any conductive material to fabricate typical shaped products like gears with high level of accuracy and quality. In present research, stainless steel (SS) alloy 316 is used to fabricate miniature gears by WEDM. The experimental array is designed according to Response Surface Methodology (RSM) based central composite face centered (CCFC). Four input parameters namely servo feed (SF), duty factor (DF), servo voltage (SV) and wire feed (WF) with three levels each are used for experimental array to investigate the process performance in terms of cutting rate (CR), and product i.e. gear quality in terms of mean roughness depth (Rz) and dimensional deviation (DD). After WEDM parameter optimization, confirmation experiments are performed at the parametric setting by considering equal importance to all response variables. A very close agreement between the experimental and predicted values have been observed.

Application of Avinit Vacuum Plasma Technologies Avinit to the Manufacture of High-Precision Full-Size Gears

Application of Avinit Vacuum Plasma Technologies Avinit to the Manufacture of High-Precision Full-Size Gears

Validation of the plane-based penetration calculation for gear skiving

To simulate the manufacturing process of gear skiving, a plane-based penetration calculation is used. With given gear, tool and process data, the simulation is able to provide characteristic process values, for example chip thickness or cutting length. In order to validate the manufacturing simulation, the simulation results are compared against the outcome of the actual manufacturing of gears based upon skiving. The characteristic process values are validated by comparing chip geometries and tool wear to the simulation results. Furthermore, the simulated gear geometry is compared to the manufactured gear.

Recent developments in sustainable manufacturing of gears: A review

Most socially aware manufacturers place a premium on awareness. Manufacturers must comply with a variety of stringent environmental criteria in order to remain competitive on a global basis. The manufacturing industry as a whole is working to increase efficiency and quality of products while also keeping the environment pure and sustainable. This could only be done by using environmentally friendly fluids and lubricating techniques when machining, decreasing waste, active waste management, and eliminating energy usage, among other things. The key services providers to other manufacturing and industrial segments, including the gear manufacturing industries, are also working on implementing strategies aimed at improved sustainability. A few more latest developments in gear manufacturing to improve sustainability can be summarized as reducing its use of mineral-based lubricating oil by employing alternate solution lubrication techniques such as least amount lubrication (MQL) and dry machining, material saving, waste reduction, reducing power consumption, and maintaining efficiency by reducing the number of gear manufacturing operations. This study examines and summarizes the present state of technologies for gear manufacture that is environmentally sustainable, as well as suggests strategies to improve productivity and the quality while maintaining environmental sustainability.

Lean six-sigma: Panacea to reduce rejection in gear manufacturing industry

This paper has covered the elimination of process variation to remove the wastages in the gear manufacturing industry. The well-known DMAIC (Define-Measure-Analyze-Improvement-Control) approach, which is the part of Six Sigma was used to decrease process variability, which contributes to a decrease the waste, thus improves total business efficiency. DMAIC methodology has been adopted for this research work in which various tools have been used, such as SIPOC (Supplier, Input, Process, Output, Customer), Pareto analysis, MSA (Measurement System Analysis), SPC (Statistical Process Control), Root & Cause analysis. A Bull gear product of the Company was selected for the improvement as this product has the highest rate of rejection. The variation in Measurement over Teeth (MOT) and Pitch circle diameter (PCD) were two defects which had a major contribution to rejection. When the framework was successfully deployed, Bull Gear rejection level was reduced from 10641.08 to 13193.21 ppm (part per million) and the sigma level increased from 4.37 to 4.81 with the sigma shift. These results demonstrated the impact of the lean six-sigma initiative at the gear company, which has operational efficiency and improved consistency to improve business performance and accommodate customer’s needs.

Proračun jačine pitinga kod materijala od livenog gvožđa i legura bakra

An attempt is made to predict the pitting strength of cast iron and copper alloy materials from their compressive yield or compressive proof strength for a reliability of 99% at 107 load cycles. The compressive yield or compressive proof strength is related to the tensile strength of ductile cast iron and copper alloy materials by a proportionality factor. Two proportionality factors are used for brittle cast iron materials. The pitting strength formulation incorporates a nominal design factor at 99% reliability which is estimated from a probabilistic model based on the lognormal probability density function. Pitting strength estimates from the predictions are compared with those of American Gear Manufacturers Association (AGMA) estimates and data from other sources. The predicted values for gray cast irons had variances in the range of -11.28% to 25%. Ductile cast iron pitting strength estimates deviated from those of AGMA by -30.28% to 1.73% and 16.76% to 36.34% for Austempered ductile irons. The variances obtained for cast bronze were from 11.17% and 14.73%, but the sample size was small. These variances appear to be reasonable due to the many factors that can influence pitting resistance. Since pitting strength data for many grades of cast iron and copper alloys are not available (especially in the public domain), they may be estimated by the expressions developed in this study for initial design sizing. Also, the pitting strength of new cast iron and copper alloy materials could likewise be estimated for initial design sizing. This will eliminate long and costly contact fatigue testing at the initial design phases, which of course is necessary for design validation.

Job safety hazard identification and risk analysis in the foundry division of a gear manufacturing industry

In today's Industry 4.0 scenario, various steps have been taken in automation for effective workplace implementations. It leads to prevent industrial incidents and prevent the injuries inside the workplace. However, the industries that have implemented the automation cannot achieve zero accidents. The practical implementation of safety is a challenging task with the cooperation of every worker. This case investigation deals with effective safety management implementation using management approaches to implement and identify the potential hazards. The case assessment is carried out using the risk assessment methods with the combination of JSA analysis method. The effective methodology potential type of incidents is identified by using the Job Safety Hazard Identification and Risk Assessment (JSHIRA) analysis. Approximately more than 50% of hazards are eliminated using the JSHIRA Methodology. The JSHIRA method critically assesses the various potential threats encounter in the workplace.

Analyzing the Environmental Consequences of Production Processes from a System of Systems Perspective: A Case of Gear Manufacturing in the Automotive Industry

Many research studies have been done to investigate different aspects of environmental challenges. In the product development context, there have been attempts to reduce the environmental impacts of associated activities including the production processes themselves. As a result, various technological improvements have been made and new production processes e.g. powder metallurgy technologies have been introduced that may demonstrate a lower environmental footprint compared to conventional processes e.g. cutting machining technologies. However, a production process with a lower environmental impact may lead to reducing the quality/performance attributes of the produced parts (gear) and probably of final products (transmission box). Therefore, the efforts intended to produce more sustainable products by using production processes with less environmental footprints may lead to some unintended consequences such as increased maintenance requirements and/or demand. This is a rebound effect from a system of systems (SoS) perspective. This paper aims to analyze the impacts of more environmentally friendly production processes on the total environmental impact associated with a product given they may have a negative impact on a part/product’s quality and performance or usage. This paper introduces a methodological approach to analyze the environmental sustainability of a production process at a SoS level. This is done by including the entire supply chain of a product-system and its interacting systems by using the results of the attributional/consequential life cycle assessment (LCA) method. The approach validity approach is demonstrated in the case of gear manufacturing in the automotive industry.

Optimization techniques to optimize the milling operation with different parameters for composite of AA 3105

Manufacturing processes become a direction to get our vision into this modern environment. Despite its expense, it is broadly used in various manufacturing. Milling is one of the most robust radical machine tools with thorough material removal. Machining parameters can perform much more complex, indexing operations and much more for gear manufacturing. The whole effort gives you a snapshot of the result of development constraints taking place on machining. As a grid material, AA 3105 was used. The material for the workpiece for the study to advance the level of expulsive materials is carbohydrated eggshell powder (RHA). The orthogonal array is designed for three stages, three-factor designs and tests on the efficiency of machining are performed using Taguchi Model, ANOVA, and regression analysis. Milling data is used to generate a statistical equation which eventually determined useful in analyzing variance. Answer surface technique, an experimental design was used for experiments. Material for the workpiece was AA 3105 as matrix material, Carbonized eggshell powder, and rice husk ash (RHA), and the tool was a high-speed steel end mill cutter. The process parameter's direct and interaction effect with the speed of the spindle, depth of cut, and feed rate was studied, which helped select process parameters to material removal rate, indicating end-friction activity immobility. The predictive models in this analysis are assumed to be similar to those observed experimentally with a confidence interval of 95 percent.

Proračun otpornosti na piting čeličnih materijala

A single expression for estimating the nominal pitting strength of steel materials, based on surface hardness, is developed from first principles for a reliability of 99% at 107 load cycles. It requires the hardness values to be measured in Vicker's hardness scale. The expression may be used for any steel material processed by hot rolling, cold drawing, quenching and tempering or case-hardening. The formulation incorporates a nominal design factor at 99% reliability which is estimated from a probabilistic model based on the lognormal probability density function. Pitting strength estimates from the expression are compared with those of American Gear Manufacturers Association (AGMA) estimates and data from other sources as indicated in Tables 3 and 4. The expression predicts lower values at low hardness but higher values at high hardness. The variance is between - 15.21% and 10.13% for through-hardened steels. For case-hardened steels, the variances range from 14.23% to 20.26% between the estimates and available data. These variances appear to be reasonable considering the many factors involved in pitting resistance. The main advantage of this study is that pitting strength of new steel materials may be estimated for initial design sizing without long and costly contact fatigue testing which of course is necessary for design validation. Also, the estimation method developed may be applied to other materials, metallic and non-metallic. Suggestions are made for estimating some pertinent pitting strength adjustment factors when considering field or service pitting strength.

Multi-objective optimization of the manufacture of face-milled hypoid gears on numerical controlled machine tool

A new method is presented for advanced manufacture of hypoid gears on numerical controlled machine tool. The tool geometry and machine tool settings are determined to introduce the optimal tooth modifications into the teeth of hypoid gears. The goal is to reduce the maximum tooth contact stresses, angular displacement error of the driven gear, and energy losses in the oil film existing between tooth surfaces. The calculation is based on the optimal variation of machine tool settings on the classical machine tool for hypoid gear manufacture. The novelty of the method is that during the machining process of teeth surfaces, the variation of machine tool settings on the cradle-type hypoid generator is conducted by polynomial functions of fifth-order. By an algorithm, this variation of machine tool settings is transferred to the numerical controlled machine tool for hypoid gear manufacture (hypoid generator). The obtained results have shown that by applying the optimal manufacture process, considerable reductions in tooth contact stresses and angular displacement errors of the driven gear, and a moderate reduction in energy losses were obtained. Therefore, by applying this new method in practice, advanced manufacture of hypoid gears on CNC hypoid generator is made possible, resulting improved operating characteristics of the hypoid gear pair.

Studying the Effective Parameters on Teeth Height in Internal Gear Flowforming Process

The flowforming process is a chipless metal forming process that is used to produce precise thin walled tubes. Manufacturing of internal gears using flowforming process is a difficult-to-achieve, but very interesting process in which the gear may be produced without the need for high forming forces and r high tooling cost. In this study, manufacturing of internal gears using flowforming process is studied. The process has been numerically analyzed and simulated. The plastic behavior of the material, and friction conditions were determined using tensile and friction tests, respectively. Several controlled test were performed to evaluate the validity of simulation results. A comparison of simulation and experimental results indicates very good agreement. Once the simulation is verified, the effects of roller diameter, thickness reduction percentage, feed rate and attack angle on tooth height were obtained using design of experiments (DOE) procedure. According to DOE results, attack angle (α), thickness reduction percentage (T), interaction between roller diameter and attack angle (D×α), and interaction between roller diameter and feed rate (D×f) are the most significant parameters affecting the tooth height. The tooth height increases with increasing the roller diameter and thickness reduction, but decreases with increasing the feed rate and attack angle.

Gear Cutting in a Globoid Pair with an Initial Cylindrical Involute Gear

The cutting of convex–concave conjugate surfaces of a globoid pair with an initial cylindrical gear is considered. Experimental assessment confirms the practical utility of the proposed approach. That permits the manufacture of globoid gears with increased load capacity when the hardness of the contacting surfaces is very different, without the need for globoid mills.

Prospects of dry continuous generating grinding based on specific energy requirement

Abstract The continuous generating grinding (CGG) is an essential finishing process to manufacture gears with excellent accuracy and efficiency. However, a large amount of heat is generated during grinding, which consumes a considerable amount of electric power for the coolant supply. Although dry grinding has attracted significant attention in recent years, the basic mechanism of heat generation for this process is not well understood. Thus, the prospects of dry CGG have been quite limited. In this study, the authors unraveled the heat generation mechanism of the dry CGG by measuring the on-site temperature in the grinding area, in addition to conducting simulations and estimating the specific removal rate and the specific grinding energy. As a result of the measurement, the entire temperature history was obtained, and a clear dependence of the measured temperature on the infeed was observed. In addition, the specific removal rate was calculated to be 2–3 mm3/mms, and the specific grinding energy was calculated to be more than 100 J/mm3. It was indicated that the specific energy could be further reduced, as a large fraction of the heat was generated by friction and not by shearing. It was revealed to be important to properly determine the pitch of the grinding wheel as well as to suppress clogging by chips and to set proper dress intervals, for realizing dry CGG with high material removal rate.

Fuzzy assessment model to judge quality level of machining processes involving bilateral tolerance using crisp data

ABSTRACT Ongoing pursuit of greater process quality has always granted manufacturers advantage in an increasingly competitive market place. This has prompted numerous researchers to develop quality assessment models for various machining processes. The Six Sigma quality management method, which determines process quality based on yield, is a useful standard of process quality which provides reference to both manufacturers for process improvements and consumers in product selection. This study has employed the loss-based Six Sigma quality index (SSQI) to analyze the quality level of a machining process with bilateral tolerance. The resulting evaluation with not only reflects loss and yield for the machining process; it also directly presents the attained quality level. In practice, must be estimated based on collected data to determine process quality. Unfortunately, uncertainty and imprecision are inevitable features of any data collection. This can lead to erroneous inferences of quality assessment using the crisp-based estimate . We, therefore, propose a fuzzy estimate of and develop the associated fuzzy statistical testing to increase the reliability of assessment and reduce miscalculation. The proposed fuzzy statistical test method is illustrated via a real-world example from a gear manufacturing plant.

Effect of Chromium Doping to Hardness Properties in the Manufacture of Spur Gears Made from Ferrous Powder

A gear is a part of a machine that has a very complex shape so that it requires special care and expertise in the manufacturing process. Powder metallurgy offers an efficient manufacturing process for the production of these complex machining parts. In this study, Cr metal powder was selected to increase the hardness properties of spur gears made from iron (Fe) powder. Doping Cr by 0%; 0.5%; 10%, 1.5% and 2.0% will be added in gear manufacturing. Water is used as a binder with a ratio of 1:15 which is then packed by 15,000 kg or 15 tons then heated or sintered at a temperature of 1200 oC for 1 hour. The shrinkage ratio of the sample to the sintering treatment averaged 4.6%. 0.2 kg of load applied to the Vickers hardness test. Vickers hardness values ​​obtained were 60, 77, 90, 184 and 211 respectively for the Cr doping of 0%; 0.5%; 10%, 1.5% and 2.0%. From these data it is found that the addition of the element Cr increases the hardness properties of iron gears. The hardness value shown is still too small, this is because there is still a lot of porosity generated in the sintering process because it is not in a vacuum condition.

Study on the optimum standard parameters of hob optimization for reducing gear tooth root stress

Optimising the hob used to manufacture gears is an attractive approach for minimizing the gear tooth root stress. However, currently available approaches often require modifying the hob for every gear case, which limits their practical application and increases design and manufacturing costs. In this study, two sets of Bezier curve parameters for gear hobs were developed to minimize the tooth root stress: one for standard hobs and the other for protuberance hobs. The two parameter sets can be used to modify any hob and effectively reduce the gear bending stress, and they are widely applicable to all common gear cases. Calculation with the finite element method indicated that the first-best parameter set for standard hobs reduced the stress of most gear cases by 6%–10%. The second-best parameter set for protuberance hobs reduced the stress of almost all gear cases by 7%–15%. The average optimisation potential was 10.73%. Meanwhile, the manufacturing cost is very low because an optimised hob can be applied to producing other gears. These two parameter sets are a significant contribution to the optimisation and manufacture of gears.

The research of oil film thickness on the gear tooth surface: A review

Increasingly demanding performance standards and operating requirements are driving the growing interest on the influence of gear oil film on reliability under the condition of high speed and heavy load. The fatigue life of gears can be increased by optimizing the oil film thickness on the gear tooth surface. The oil film thickness can reflect the ability of the gear to resist pitting and gluing failure. Many theories and experiments are devoted to the study of the oil film thickness. The improvement of gear manufacturing accuracy also makes the influence of tooth surface roughness on oil film thickness not negligible. In order to compile and categorize key investigations in an expansive field with substantial recent research, this work reviews oil film thickness with focus on numerical calculation methods, influence of gear surface roughness on oil film thickness and fatigue life analysis based on oil film thickness.

The features of the gears profile forming by the electrical discharge machining

The article describes the possibilities of using electrical discharge machining for the manufacture of cylindrical gears. The developed method of calculating the coordinates of the reference points of the trajectory of the wire electrode-tool provides shaping of the surfaces of the teeth of the involute wheels in a form similar to that obtained by the edge tool using the generating method. The description of a software tool for automating the technological preparation of production of gears, implemented on a electrical discharge machine when processing blanks from various materials.

Adaptive data-driven modular control approach to computer aided process planning for manufacturing spiral bevel and hypoid gears

Machine setting modification has been an increasingly important access to the accurate flank manufacturing geometric accuracy control for spiral bevel and hypoid gears. More recently, machine setting driven integration of the theoretical design and the actual gear manufacturing is gaining more and more attention. In this paper, the traditional machine setting modification is extended to the case when higher-order component of the prescribed ease-off flank topography is investigated in form of high-order polynomial expression. Moreover, the actual gear manufacturing and general measurement are integrated into an adaptive data-driven high-order machine setting modification. In particular, this modification method is used to perform adaptive modular control for computer aided process planning (CAPP). Here, a data-driven operation and optimization is developed for adaptive high-order modification. It mainly includes: (i) Polynomial fitting and its optimization by using overall interpolation based on energy method, (ii) Data-driven ease-off flank parametrization based on the fastest descent Newton iteration method, (iii) adaptive control strategy by considering the sensitivity analysis, and (iv) Levenberg-Marquardt (L-M) based approximation for high-order machine setting modification. Given numerical test can verify the proposed method.