Broaching Tool Research Articles

Tool wear prediction in broaching based on tool geometry

Abstract The aircraft engine is a safety-critical part of an aircraft. Constructive modifications resulting in ecological and economic improvements of the engine lead to necessary changes in manufacturing processes. The turbine discs in the low-pressure section are made of temperature resistant nickel-based superalloys. For the connection of the turbine blades with the disc, fir-tree slots are machined by broaching. The broaching process achieves high geometrical accuracy as well as process reliable rim zone properties. Alternative manufacturing processes such as milling or wire electrical discharge machining are still the subject of research in many applications and do not yet achieve the required process reliability. Especially in finishing operations, tool geometry is complex. In previous research work, the local rake angle and, as a result, the acting cutting force were determined analytically and empirically. Based on these results, the relationship between tool geometry, cutting force, and tool wear will be investigated in this work to enable a cutting length dependent prediction of tool wear. The aim of this work is a model-based prediction of tool wear for a given cutting length and a previously unknown tool geometry. For this purpose, a method was developed to predict tool wear using empirical test data as well as internal machine data. With the results of this work, it is not only possible to identify critical points on newly developed broaching tools by maxima of the cutting force, but also to predict wear locally, depending on the cutting length.

Improving the technology for restoring worn parts based on cold plastic deformation

Technological control scheme for forming worn parts during their restoration by deforming broaching is proposed. Particular attention is paid to the study of the stress-strain state, which provided the conditions for creating the necessary plastic flow of the product material towards the worn areas and made it possible to compensate the wear amount in these areas of the product and provide an allowance for subsequent machining. Taking into account the peculiarities of parts restoration technological process, the relationship between the required circumferential strain of the outer surface and the total tension on the hole is established. The influence of the number of deforming elements that perform the required deformation on the accumulated strain on the inner surface of the part was investigated. This made it possible to establish that the maximum accumulated strain of the inner surface is provided by the maximum number of elements with a minimum tension on the element. On the outer surface, the value of the accumulated strain does not depend on the number of deforming elements, but is determined only by the total tension and the workpiece thickness. Based on the simulation of deforming broaching in a wide range of changes in operating parameters, tool geometry and workpiece thickness, an analytical dependence was obtained to determine the angle that ensures the absence of axial strains when the workpiece is deformed. The necessary broaching modes and tool geometry were determined, which will ensure the required dimensions of the machined or restored part.

Analytical and numerical optimization of broaching tool tooth distribution

This paper presents a detailed mathematical analysis of the effect of tooth distribution on the stability of broaching operations. Analytic and numeric techniques are employed to analyse a simplified one-degree-of-freedom mechanical model of variable pitch broaching, to assess its stability, and to find the optimal tooth distances maximizing robustness against harmful self-excited chatter vibrations. A novel modelling approach, considering a theoretical infinitely long broaching tool, draws parallels with variable pitch milling, and analytic formulas for tuning milling cutters are extended to broaching tools. For a further increase of robustness, and to take feasibility constraints into account, a goal function based on the semi-discretization and spectral collocation techniques is implemented in a direct numeric optimisation framework. A new, detailed derivation of the corresponding parameter gradients is presented to enable the use of gradient descent techniques. Since broaching is inherently a time-limited process, optimal parameters found in this manner are then validated via time domain simulations to show the desirable transient behaviours achievable by this ideal tuning of the tool geometry.

DIGITAL GEOMETRY GENERATION OF HIGH PRECISION BROACHING TOOL CUTTING EDGES THROUGH IMAGE PROCESSING ALGORITHM

In this paper an efficient geometry description algorithm is proposed that reads the cutting-edge points of an arbitrary broaching tool from the provided model in a pixelated format which is surely available in any engineering environment. The created geometry can be scaled arbitrarily and used for simulations, ensuring adaptability due to its point cloud like format. High precision machining requires large resolution (microns) that often leads to unmanageable data storage needs with increased calculation time. To overcome these problems, the proposed algorithm is built around a pseudo arc-length-like continuation of the cutting-edge pixels, which works on broaching tools due to the cutting-edge geometry is free from any loops or isolas. This method provides all the important data including the high-resolution edge sections, related chip thicknesses and the normal directions for dynamic simulations and manufacturing.

The influence of cutting edge microgeometry on the broaching of Inconel 718 slots

In aero-engine production, the dovetails (firtrees) of turbine discs are manufactured by broaching. Introducing innovative micro-geometry modifications to broaching tools can significantly influence cutting force, energy consumption, tool wear, and cutting edge temperature during broaching. Therefore, this study aims to study this influence by treating the cutting edge by brushing with ceramic bristles. The results reveal that the increase in cutting edge radius significantly influences the cutting force, particularly its component in the forward direction, equating it to the tangential component. Furthermore, during the experimental tests, considerable wear was observed on the cutting edge, which generated strong vibrations detected through the force signals, accounting to poor surface quality and a higher coefficient of friction close to 1. The 2D simulations generated information on temperature distribution along the cutting edge profile. On the other hand, was observed the presence of subsurface damage characterized by distorted grain boundaries aligned with the cutting direction, along with the formation of uninterrupted non-serrated chips due to thermoplastic deformation. Further, 12 µm cutting edge radius exhibits the best performance in terms of cutting force, temperature, and surface quality.

Early detection of tool wear in electromechanical broaching machines by monitoring main stroke servomotors

This paper aims to provide researchers and engineers with evidence that sensorless machine variable monitoring can achieve tool wear monitoring in broaching in real production environments, reducing production errors, enhancing product quality, and facilitating zero-defect manufacturing. Additionally, broaching plays a crucial role in improving the quality of manufacturing products and processes. These aspects are especially pertinent in aeronautical manufacturing, which serves as the experimental case in this study.The research presents findings that establish a correlation between the variables of a broaching machine’s servomotors and the condition of the broaching tools. The authors propose an effective method for measuring broaching tool wear without external sensors and provide a detailed explanation of the methodology, enabling reproducibility of similar results. The results stem from three trials conducted on an electromechanical vertical broaching machine, utilizing cemented carbide grade broaching tools to broach a superalloy Inconel 718 test piece. The machine data collected facilitated the training of a set of machine learning models, accurately estimating tool wear on the broaches. Each model demonstrates high predictive accuracy, with a coefficient of determination surpassing 0.9.

Asymmetrical cutting-edge design of broaching tool based on FEM simulation

Finite element method (FEM) based model of broaching Inconel 718 was established to optimize an asymmetrical cutting-edge by the commercial software AdvantEdge in this paper. The asymmetrical cutting-edge form by two circles was proposed. The power-law (P-L) material constitutive model, including strain hardening, strain rate hardening and thermal softening was developed by split Hopkinson pressure bar (SHPB) test and high-temperature Vickers hardness test. The parameters of thermal properties were measured by laser flash diffusivity apparatus. The friction model between TiN (The outer layer coating material of the tool) and Inconel 718 was obtained by ball on disc friction test. The simulated and experimental results have been compared comprehensively in the items of chip formation and tool wear width. The results showed that the simulated results were consistent with the experimental results. The average errors of chip curl radius, chip thickness, wear width of rake face and flank face were 7.68%, 3.56%, 13.64% and 12.24%, respectively, which proved the accuracy of the simulation model. Then the optimal asymmetrical cutting-edge of broach were obtained through orthogonal test based on the accurate FEM model. The rise per tooth of the optimal broach tool is 0.04 mm/tooth, the rake angle is 13°, the circle radius R1 is 0.13 mm, and the circle radius R2 is 0.02 mm.

ShuffleNet v2.3-StackedBiLSTM-Based Tool Wear Recognition Model for Turbine Disc Fir-Tree Slot Broaching

At present, deep learning technology shows great market potential in broaching tool wear state recognition based on vibration signals. However, traditional single neural network structure is difficult to extract a variety of different features simultaneously and has low robustness, so the accuracy of wear status recognition is not high. In view of the above problems, a broaching tool wear recognition model based on ShuffleNet v2.3-StackedBiLSTM is proposed in this paper. The model integrates ShuffleNet v2.3, which has been channel shuffling, and StackedBiLSTM, a long and short-term memory network, to effectively extract spatial and temporal features for tool wear state recognition. Based on the innovative recognition model, the turbine disc fir-tree slot broaching experiment is designed, and the performance index system based on confusion matrix is adopted. The experimental research and results show that the model has outstanding accuracy, precision, recall, and F1 value, and the accuracy rate reaches 99.37%, which is significantly better than ShuffleNet v2.3 and StackedBiLSTM models. The recognition speed of a single sample was improved to 8.67 ms, which is 90.32% less than that of the StackedBiLSTM model.

Estimation of Drag Finishing Abrasive Effect for Cutting Edge Preparation in Broaching Tool.

In recent years, cutting edge preparation became a topic of high interest in the manufacturing industry because of the important role it plays in the performance of the cutting tool. This paper describes the use of the drag finishing DF cutting edge preparation process on the cutting tool for the broaching process. The main process parameters were manipulated and analyzed, as well as their influence on the cutting edge rounding, material remove rate MRR, and surface quality/roughness (Ra, Rz). In parallel, a repeatability and reproducibility R&R analysis and cutting edge radius re prediction were performed using machine learning by an artificial neural network ANN. The results achieved indicate that the influencing factors on re, MRR, and roughness, in order of importance, are drag depth, drag time, mixing percentage, and grain size, respectively. The reproducibility accuracy of re is reliable compared to traditional processes, such as brushing and blasting. The prediction accuracy of the re of preparation with ANN is observed in the low training and prediction errors 1.22% and 0.77%, respectively, evidencing the effectiveness of the algorithm. Finally, it is demonstrated that the DF has reliable feasibility in the application of edge preparation on broaching tools under controlled conditions.

Design and Development of Broach Cleaning Mechanism

Broaching is most commonly used in industries for rapid and correct profiling of metal work piece. Broaching can be used to generate any desired shape by means of tool called broach. The profile that is largely produced is keyway and Splines. The keyways and splines are required in automotive components such as gears and pulleys. The closure relates to Design and development device used for cleaning broach tool compromising of a circular brush that rotate around the broach through a compressed air (Pelton Wheel turbine Like Mechanism) designed specifically for broaching machine to remove the metal chips accommodated in-between broach tool tooth and thus improve productivity of the broaching machine. A basic overview of burr formation and removal is presented in this paper. The main advantages, disadvantages, limitations, part quality and precision of these operations are presented.

Combined lubrication of surface texturing and copper covering for broaching tool

Broaching is widely used in the aerospace field owing to its high efficiency and heavy load. However, heavy-load cutting causes intense squeezing and friction in the tool-chip contact area, resulting in a lack of lubrication. Therefore, three textures (i.e., micro-pit, stripe, mesh) are prepared on the rake face of broaching tool with a laser processing technique to improve cutting performance. Afterward, textures are covered with copper using the reciprocating rotational friction to enhance the wettability and heat dissipation capacity of the broaching tool. Experiments approve that striped textures covered with copper reduce the cutting force by 14.6% and the cutting temperature decreases from 90.13 to 76.9 ℃, compared with non-textured cutting teeth. Obtained results indicate that the wettability of cutting fluid on the tool surface is significantly improved due to the capillary force of micro-pores generated by the copper covering, especially in the direction to the cutting edge. Furthermore, the copper debris absorbs heat quickly in the cutting areas and is subsequently taken away by chips and cutting fluids, thereby reducing the cutting temperature.

Experimental Study on Surface Integrity of Ti6Al4V by Broaching

The performance of many parts in the airplane, aircraft engine and biomedical implants is highly related to their fatigue life, which is clearly depend on the condition of their surface integrity. The geometry parameters of broaching tools have an important influence on the surface integrity after broaching Ti6Al4V alloy. Therefore, this research studies the surface integrity of Ti6Al4V by broaching. The surface integrity is studied at different geometric parameters such as rake angles (α, and α0), clearance angles (β, and β0), and radius of the cutting edge (r0) in two last teeth of the broaching tool that perform chipping. The broached surface integrity is assessed in cases of surface roughness, microstructural, residual stresses, and micro hardness. These results show that the sample broached by tool number 1 (α = 18.4, β = 3.1, α0 = 45, β0 = 9, r0 = 0.02) had higher surface integrity because it was the smoothest surface and the thinnest deformed layer among the other samples. Since the main criterions in selection of the optimal tool are to create the smoothest surface and the least deformed layer depth in the broached sample, tool number 1(α = 18.4, β = 3.1, α0 = 45, β0 = 9, r0 = 0.02) is suggested as the optimal tool.

Design, development and test of a novel broach for long polypropylene tubes

Polymers are frequently used for a variety of applications in industry. One relevant field is plastic tubing. As plastic tubes are manufactured from thermoplastic material through hot-extrusion their dimensional accuracy is only moderate. Wherever high accuracy on tube diameters and roundness are required, the conventional production techniques reach their limits and more complex technologies are needed. Known approaches from metal machining are deep hole drilling and internal broaching. However, machining processes with chip removal on polymeric materials are not so common. Therefore, the authors studied cutting operations of polypropylene experimentally. Based on their findings they designed and built an internal broach for the machining of polypropylene tubes. Finally, the authors tested their developed broaching tool in a relevant industrial environment. The tool not only fulfills the dimensional machining requirements but also solves the present chip evacuation problem in a unique way. It enables free cutting through the whole operation and creates continuous straight chips with no need for chip breakers. Consequently, the timely cleaning step, required in traditional broaching, can be eliminated, which reduces the lead time significantly. Furthermore, the set of materials allows dry broaching. Coolant is not necessary. This leads to less waste, a cleaner production line, and avoids damage through aggressive liquids. Lastly, their design ensures that no loss of dimension occurs when resharpening the tool.

Wheel orientation calculation for helical rake flank sharpening of broaching tools

Helical rake flank is an important structure of helical broach tools. Its perfect sharpening is crucial to maintain the working performance of the tool and prolong the tool life, which is obtained via proper wheel orientation and suitable grinding processes. In practical, wheels with diverse profiles are adopted to satisfy the sharpening for various rake flanks. Therefore, wheel orientation identification methods with strong robustness are expected to deal with general helical rake flank sharpening tasks. Besides, proper grinding processes should be devoted to helical rake flank sharpening to improve the quality of broach tool. This study developed a wheel orientation calculation method that combing the specific process for helical rake flank sharpening with involving discrete enveloping. Firstly, a general model for grinding wheel is established, and the swivel-tilt-based orientation and positioning parameters of wheel are given. Then, through approximating the grinding motion as a serial of discrete wheels, the machined profile on the broach tool axial-section is expressed as the external enveloping profile of the intersection curves between the wheels and the tool axial-section. After distinguishing the enveloping profile by points along radial direction, the derivation of the instant contact line was provided. Furthermore, the mathematic model of the specific process about helical broach rake flank sharpen is established to enhance the wheel orientation identification algorithm. At last, both experiments and simulations are implemented to verify the effectiveness of this method and to investigate the influences of the process constrains via solution space.

The slide broaching burnishing and the influence of deformation on roughness of 314L stainless steel sleeves

The paper is intended to inform the reader of the effectiveness of the technological burnishing process utilizing a three burnishing broach mandrel for the inner finishing of cylinder surfaces. The burnishing tools were constructed out of 40HM steel, and the burnishing broach tool was secured in a Hydraulic Press MX-340G. The mechanism of slide burnishing broaching consists of prepared burnishing mandrel pushers with diameters Ø17 mm. The sleeves were designed to achieve a reduction ratio in burnishing of 0.3 mm to 0.5 mm. Here, slide burnishing was conducted in two passes, (down and then up). The burnishing was performed at a constant rate of feed and with the same force for all samples. In the thesis, classifications and characteristics of burnishing with conditions of process parameters and the used instrumentation are presented.

WITHDRAWN: Effect of Micro-texture of Flank Surface on Broaching Force and Surface Quality of Workpiece

Abstract The application of surface micro-texture in the field of processing tools has become one of the most effective ways to improve economic efficiency in the manufacturing industry. Broaching, as a highly efficient processing method, is widely used in various industries. In order to improve the cutting performance of broaching tools, three types of surface micro-texture were made on the flank face of broach by Nd: YAG laser: (i) pit in the A1 area (5-14 teeth), (ii) groove in the A2 area (15-24 teeth), (iii) V-type in the A3 area (25-34 teeth), respectively. Then, dry broaching experiments were carried out with a micro-texture broach tool (MBT) and the conventional broach tool (CBT) on the built broaching test system. The results show that compared with the CBT, the MBT tool can effectively reduce the broaching force and improve workpiece surface quality. The largest broaching force of the micro-textured teeth with pit is reduced by 6.62%, while the groove and V-type teeth are 4.84% and 5.63%, respectively. The workpiece surface quality of MBT tool is increased 51.87% compare CBT tool processing. This paper proved that the application of micro-texture on broaches can certainly improve processing quality and reduce energy consumption.

Modeling and assessment of broaching tool with grooves on the flank face

The last decade has witnessed an explosion of interest in the cutting load analysis for multifarious tools, especially in experiments and classical 2D model. But the cutting load model for broaching tool with grooves is still not clear and functional. In this paper, a new cutting load model applied to the broaching tool, which has some grooves on the flank face of the tooth, is reported. The model takes account of the load reduction effect of grooves on the tool teeth and the load strengthening effect of the bumps on the workpiece. Then, based on the new model, the cutting load simulation analyses for 5 different types of broaching tools are presented and compared with the corresponding experimental results. The results show that cutting load can be well assessed with the proposed new model. And an interesting phenomenon is found that the grooves on the tool teeth are not the more, the better. Among the 5 different types of broaching tools researched, 4/5 type broaching tool shows the best cutting performance.

Design of Broaching Tool Using Finite Element Method for Achieving the Lowest Residual Tensile Stress in Machining of Ti6Al4V Alloy

The aim of this study, is to use finite element simulation to achieve the optimal geometry of a broaching tool that creates the lowest tensile stress at the machined surface of the Ti6Al4V alloy. It plays a major role in reducing production costs and improves the surface integrity of the machined parts. The type and amount of residual stress determined by the thermal and mechanical loads transmitted to the workpiece. In this research, the two-dimensional simulation of the broaching process is done by finite element DEFORM-2D® software for the two end teeth of the tool that perform the cutting operation. In simulating the first tooth, Response Surface Method is used to select the desired controllable parameters of the process such as cutting speed, rake angle, clearance angle, rise per tooth and depth of cut. In order to establish low thermal and high mechanical load in workpiece, multi-objective genetic algorithm employed after perform simulation in the first tooth. In simulating the second tooth, Response Surface Method used to select desired controllable parameters of the process such as rake angle, clearance angle and radius of cutting edge. For the second tooth, a multi-objective genetic algorithm has been used. Ultimately, the geometry of the broaching tool utility has been designed to store the lowest tensile residual stresses in the machined surface for Ti6Al4V alloy.

Identification of the relationship of the magnitude of the rise tool tooth and the physical and mechanical properties of the material and the tool broaching

The article considers the existing methods of designing a broaching tool. The analysis revealed that they do not take into account the change in the physicomechanical measurements of the workpiece and tool occurring with the material at various temperatures in the cutting zone. The article offers a technique for taking this circumstance into account to increase the productivity of the pulling process. The method will allow to design a broaching tool for processing internal surfaces and it will increase the productivity of machining of internal surfaces.

Suitability of MC90 Intermet material for optimal design of carbon-free broach tool

Machining involves shaping different parts and producing complex profiles. One of the machining operation – Broaching is usually done to produce a wide range of complicated shapes, designs, internal and external pattern such as keyways, splines, slots, gears etc. Nowadays broaching is performed by using coated high speed steel tool material. However, due to lower hot hardness, the tool variables should be shortened and the process of lubrication also becomes compulsory. In order to overcome these defects, a material having higher hot hardness and an elevated – Temperature Conductivity (than the HSS) is preferred. So a hopeful alternative is the usage of a non-carbon cutting tool material – MC 90 Intermet. The article discusses the characteristics and the experimental procedures conduced in this material. This paper also discusses a methodology for designing an optimal broaching tool, considering its geometrical aspects. So, hence infusing this design structure into MC 90 Intermet yields a promising new alternative broach tool.