Incremental Sheet Metal Forming Research Articles

Performance Analysis of Multi-Point Incremental Forming Tool using Martensitic AISI 420 Sheet Metals

Incremental Sheet metal Forming (ISF) Process is a suitable process which helps to produce various parts used in automotive sector by rapid prototyping. This method of producing a prototype helps industry in reducing the production cost. In ISF process, a final product is evolved through local deformation of the sheet metal made by the tool. Usually better formability is obtained when the tool makes a better contact with the sheet metal throughout the process. Improved formability elevates dimensional accuracy of the product, thus increases the market value of the product. A new tool with multiple ball ends capable of making multiple mating points over sheet metal was used in this research to enhance the efficiency of formability and surface finish. Ability of the new Multi-Point Incremental Forming Tool (MPIF) was investigated and compared to the existing Single Point Forming Tool (SPIF) based on the formability and surface finish. Forming Limit Diagram (FLD), Strain Distribution (SD) and Scanning Electron Microscope (SEM) were used to examine the formability of the sheet metal. The SEM & 3D-Surface roughness profilometer were used to observe the sheet metals surface finish. In addition to these experimental techniques a simulation results were also used to predict the stress and strain rate during forming process. The experimentation and simulation outcome shows that the MPIF provides superior formability and surface finish.

Comparison of Vibration Assisted Single Point and Two-Point Incremental Forming of Sheet Metal

Vibration-assisted single-point incremental forming (VASPIF) and two-point incremental forming(TPIF) are two innovative techniques employed in sheet metal forming processes, each offering distinct advantages and limitations. VASPIF utilizes high-frequency oscillations applied to the forming tool to reduce friction and improve material flow, resulting in enhanced formability and surface finish. Conversely, TPIF employs two independently controlled forming tools to deform the sheet metal incrementally, allowing for greater geometric complexity and improved accuracy compared to VASPIF. However, TPIF typically requires more complex tooling and setup, potentially increasing manufacturing costs and setup time. Both techniques have shown promise in improving the formability of sheet metal components while offering unique capabilities suited to specific manufacturing requirements. Vibration-assisted single-point incremental forming (VASPIF) and two-point incremental forming (TPIF) are two advanced methods used in sheet metal forming, each with its unique characteristics, advantages, and limitations. In this comprehensive comparison, we will delve into the fundamental principles, process parameters, applications, advantages, and challenges associated with both techniques. Starting with VASPIF, this innovative approach involves applying high-frequency oscillations to the forming tool during the incremental forming process. These vibrations serve to reduce friction between the tool and the work piece, facilitating material flow and enhancing formability. By effectively decreasing the frictional forces, VASPIF enables the deformation of difficult-to-form materials and improves the surface finish of the formed parts.

A novel framework for designing and manufacturing cranial prostheses through incremental sheet metal forming

A novel framework for designing and manufacturing cranial prostheses through incremental sheet metal forming

Investigating the effect of input parameters on tool wear in incremental sheet metal forming

Abstract Over the years incremental sheet metal forming (ISMF) has developed as a futuristic technique in which the metal sheets are transformed into the final product with the use of a solid metallic rod having a designed end, rather than a dedicated die. The production lead time is quite high in this process as compared to the conventional sheet forming methods. ISMF is most suitable for developing model for the purpose of research and development, manufacturing of the customized part and for low-volume production. Tool life is an important criterion for determining feasibility of any manufacturing process. The sliding of the forming tool over the clamped metal worksheet during the ISMF is another important aspect for understanding the tool-wearing behaviour. The present study has investigated the wearing of the 440C grade steel forming tool during the ISMF of aluminum grade AA3003-O. It has examined the process statistically to establish that the step downsize (P = 0.021) and sheet metal thickness (P = 0.005) significantly influence the wearing of 440C steel tool. The coefficient of performance, i.e., R 2 has been reported as 92.0 % with an adjusted R 2 of 81.9 %.

Investigation of Metal Wire Mesh as Support Material for Dieless Forming of Woven Reinforcement Textiles

Within the rapidly growing market for fiber-reinforced plastics (FRPs), conventional production processes involving molds are not cost-efficient for prototype and small series production. Therefore, new flexible forming techniques are increasingly being researched, many of which have been inspired by incremental sheet metal forming (ISF). Due to the different deformation mechanisms of woven reinforcement fibers and metal sheets, ISF is not directly applicable to FRP. Instead, shear and bending of the fibers need to be realized. Therefore, a new dieless forming process for the production of FRP supported by metal wire mesh as an auxiliary material is proposed. Two standard tools, such as hemispherical punches, are used to locally bend a reversible layup of metal wire mesh and woven reinforcement fiber fabric enclosed in a vacuum bag. Therefore, the mesh aids in introducing shear into the material due to its ability to transmit compressive in-plane forces, and it ensures that the otherwise flexible fabric maintains the intended deformation until the part is cured or solidified. Basic experiments are conducted using thermoset prepreg, woven commingled yarn fabric, and thermoplastic organo sheets, proving the feasibility of the approach.

Investigating the surface roughness of calamine brass in incremental sheet metal forming

Incremental sheet metal forming (ISMF) is an emerging metal sheet forming technique. ISMF does not require any special/dedicated dies for shaping the metal sheet into a desired part. The forming technique is an alternative for customized part generation, prototype making, and low-volume product manufacturing. The experimental investigation is focused on finding the significance of process parameters on the average surface roughness of the ISMF part. Limited process parameters were taken that majorly influenced the ISMF. Calamine brass (Cu67Zn33) is preferred for home alliance and grocery items because of its sustainability and corrosion-resistant properties therefore thin sheets of it were taken as worksheets. The surface roughness of the formed part was measured through atomic force microscopy (AFM) technique. Statistical analysis confirmed that the step-down size, feed rate of the tool, wall angle, and the thickness of metal sheet whose P-values were 0.013, 0.052, 0.030, and 0.036 respectively were significant for average surface roughness. Their contribution was calculated as 76.71%, 0.025%, 13.67% and 0.89% respectively.

Investigation of feature-based and space-filling tool path strategies for formability in incremental sheet metal forming

Investigation of feature-based and space-filling tool path strategies for formability in incremental sheet metal forming

A Study on the Effect of Multistage Toolpath in Fabricating a Customized Cranial Implant in Incremental Sheet Metal Forming

Incremental sheet forming (ISF) process offers a high degree of flexibility in the manufacturing of different sheet parts, which makes it an ideal candidate for prototype parts as well as efficient at fabricating various customized products at low production costs compared to traditionally used processes. However, parts produced in this process exhibit notable geometrical inaccuracy and considerable thickness reduction. In this paper, the single point incremental sheet forming variant of the process has been implemented to manufacture a highly customized cranial implant starting from the computed tomography (CT) scan data of the patient's anatomy. A methodology, from the modeling to the realization of the implant, is presented and discussed. The primary aim of the research was to analyze and study the effect of the multistage toolpath strategy compared to the traditional single-stage toolpath in terms of geometrical accuracy and thickness distribution. The final results show that the part formed in the multistage toolpath strategy exhibited a more uniform thickness distribution compared to the single-stage approach. Regarding the geometrical accuracy, the deviation analysis between the nominal and actual data has revealed that the multistage forming has significantly enhanced the final geometrical accuracy of the formed part.

The Effect of Tool Path Strategy on Mechanical Properties of Brass (65-35) in Single Point Incremental Sheet Metal Forming (SPIF)

In this paper, three tool paths strategies; iso-planar, helical and adaptive have been implemented to investigates their effect on the mechanical properties of Brass 65-35 formed by single point incremental sheet metal forming process. To response this task, a fully digital integrated system from CAD modeling to finished part (CAD/CAM) for SPIF process has been developed in this paper.The photo-micrographs shows an identical grain formation due to the plastic deformation of the incremental forming process, change in the grain shape and size was observed. It's found that the adaptive tool path play a significant role to increase the hardness of the formed specimen from (48 to 90 HV) and the grain texture of the formed specimen found as round shape, while the hardness is increased in little amount from (48 to 74 HV) in the specimen formed using helical and it’s grain texture was found as needle shape.

The Effect of Tool Path Strategy on Twist Behavior In Single Point Incremental Sheet Metal Forming

In Incremental sheet metal forming process, one important step is to produce tool path, an accurate tool path is one of the main challenge of incremental sheet metal forming process. Various factors should be considered prior to generation of the tool path i.e. mechanical properties of sheet metal, the holding mechanism, tool speed, feed rate and tool size. In this work investigation studies have been carried out to find the different tool path strategies to control the twist effect in the final product manufactured by single point incremental sheet metal forming (SPIF), an adaptive tool path strategy was proposed and examined for several Aluminum conical models. The comparison of the proposed tool path with the conventional iso planar and helical tool paths shows that there is no effect of twisting in the final model when using adaptive tool path, while the twisting effect are clearly observed and measured in the final product when using both iso planar and helical tool path When forming 80 and 110mm depth conical cup. The time of forming has been measured and its observed that in adaptive tool path the time of forming is less than 8.7 %from the helical tool path when forming conical cup with 50mm depth and less than of 8.91% when forming conical cup with 110mm depth

Formability and surface finish analysis of AA-6061 sheets in multipoint incremental forming process

ABSTRACT Incremental sheet metal forming (ISF) is` a versatile manufacturing process carried out without the help of a die and is one of the most sought-after research areas. This research work provides a deep investigation into the impact of input parameters on formability and surface roughness. A Multipoint Incremental Forming (MPIF) tool is used in this work. Through MPIF, better surface finish and improved formability can be achieved. Also, the time required for metal forming can be reduced. The main goal in this work is to obtain improved formability and excellent surface finish in the MPIF process. Response Surface Methodology (RSM) and Multi-Objective Genetic Algorithm (MOGA) are used in this work to find the optimum combination of process parameters, including sheet thickness, vertical step depth, speed and feed rate to obtain improved formability and surface finish.

Processing Strategies for Dieless Forming of Fiber-Reinforced Plastic Composites

The demand for lightweight materials, such as fiber-reinforced plastics (FRP), is constantly growing. However, current FRP production mostly relies on expensive molds representing the final part geometry, which is not economical for prototyping or highly individualized products, such as in the medical or sporting goods sector. Therefore, inspired by incremental sheet metal forming, we conduct a systematic functional analysis on new processing methods for shaping woven FRP without the use of molds. Considering different material combinations, such as dry fabric with thermoset resin, thermoset prepreg, thermoplastic commingled yarn weave and organo sheets, we propose potential technical implementations of novel dieless forming techniques, making use of simple robot-guided standard tools, such as hemispherical tool tips or rollers. Feasibility of selected approaches is investigated in basic practical experiments with handheld tools. Results show that the main challenge of dieless local forming, the conservation of already formed shapes while allowing drapability of remaining areas, is best fulfilled by local impregnation, consolidation and solidification of commingled yarn fabric, as well as concurrent forming of prepreg and metal wire mesh support material. Further research is proposed to improve part quality.

Investigation of the suitability of a fused filament fabricated tool for incremental sheet metal forming

Investigation of the suitability of a fused filament fabricated tool for incremental sheet metal forming

Investigation of surface roughness in multi point incremental sheet metal forming

Surface quality is one of the key parameters in Multipoint Incremental Sheet forming (MPIF). This work focuses on finding the factors influencing surface quality in MPIF. Three different parameters namely speed, feed and step depth are considered for the study. The effects of the above input variables on surface quality was investigated by Taguchi’s design of experiments and finally the optimum input parameters combination for minimum surface roughness is found. The most influencing parameter is found to be step depth followed by speed and feed. The findings were validated by a confirmation test.

An Approach to Measure Tool Wear through Image Processing in Incremental Sheet Metal Forming

The Incremental sheet metal forming (ISF) is come into the light due to its unique forming technique. In ISF, the metal sheets are transformed into the final product without using dedicated died. The plastic deformation of metal sheets is conducted through a simple forming tool. Its processing time resembles that the ISF is suitable for the formation of customized products, prototypes, and low volume production. Tool life in manufacturing processes is an important consideration for productivity. The present study is an approach to use image processing techniques to measure the exact location and amount of tool wear in the ISF tool which is made of 440C steel. Presently the complex histogram plot is under study. Therefore to predict the tool wear, feed-forward backpropagation (FFB) algorithm is utilized. It is reported that the maximum predicted tool wear of 0.0663mm is found in the trail run 05 with an error of 0.0104mm. The best-fitted value of the FFB model is observed at the epoch 05 with the value of 5.922e-005. The overall coefficient of performance i.e. R2 of FFB modeling is reported as 90.52 % with the mean absolute error (MAE) of 0.0042 which shows a good agreement of the prediction model.

Experimental investigations of warm incremental sheet forming process on magnesium AZ31 and aluminium 6061 alloy

Aerospace, automobile and biomedical sector focuses on innovative rapid manufacturing processes, which can enable product customization, reduction in cost and manufacturing lead time. Aerospace, automobile and biomedical industries mostly use magnesium AZ31 and aluminium 6061 alloy materials for manufacturing of products because of their lower elastic modulus, excellent corrosion and fatigue resistance. The conventional sheet metal forming processes often require additional tools like punch and die and would not be economically viable to produce the customized structure for applications. An emerging forming technique known as warm incremental sheet forming process is evolved, which is capable of forming intricate, asymmetrical components at elevated temperature with localized deformation method. The characteristics of warm incremental sheet forming process suggest the need for the investigation of magnesium AZ31 and aluminium 6061 alloy materials for wide application of the process. Experimental investigation on the influence of process parameters on warm incremental sheet metal forming of magnesium AZ31 and aluminium 6061 alloy materials using electric heating technique was studied. Experimental results revealed that magnesium AZ31 and aluminium 6061 alloy sheet metal component formed with incremental depth of 0.1 mm, wall angle of 50° and temperature of 300°C showed maximum formability and thickness reduction with minimum geometrical deviation.

Analytical approach to damage prediction in incremental sheet metal forming

Incremental sheet metal forming (ISF) is known to exhibit higher formability compared to conventional stamping. It is established that the mechanism of failure during ISF is by fracture occurring at higher effective strain than the local necking observed in traditional forming processes. The deformation limit in ISF is therefore estimated numerically using a suitable continuum damage model. However, simulation of incremental forming process including the damage model is often computationally expensive. In the present work, a simpler alternative combining finite element simulation and numerical solution outside finite element software is utilized. The finite element simulation is performed ignoring the damage model. The stress and strain history thus obtained in critical locations is utilized to estimate the damage evolution. The proposed method is useful when utilizing uncoupled continuum damage models. The proposed method is validated for typical cases by comparing it against the predictions from finite element method. Excellent correlation is observed between the proposed method and finite element simulation results.

Automatic generation of 3d spiral tool path for incremental sheet metal forming of mechanical parts with complex geometry

Incremental sheet metal forming is a flexible manufacturing technology that allows to form of various components on the same milling machine, without expensive tools. A hemispherical tool moves along a CNC-controlled tool path and deforms the sheet into the desired shape. The tool path has a significant role in the geometric accuracy of the final part. There has been very little research on the problem of the forming of sophisticated parts with asymmetric wall angles. This paper presents a new approach to generating optimized tool paths for single-point incremental sheet forming (SPIF). At first, a strategy is proposed for the automatic generation of a 3D tool path during forming in a single-step operation. Then, a systematic technique of creating intermediate shapes is investigated by defining tool paths interpolated from the final part shape. The proposed methodology is applied to form a hip cup prosthesis. This part has a complex asymmetric geometry with important angles, a multi-step approach is used. The proposed methodology to define the different tool paths was implemented in Matlab. A numerical simulation of the incremental forming process is performed to predict the final geometry of the aluminum sheet. A comparison of desired and predicted geometries shows the reliability of the proposed method.

Evaluation of uncoupled ductile damage models for fracture prediction in incremental sheet metal forming

The formability limit in a typical incremental sheet forming (ISF) far exceeds the conventional estimate assuming necking failure. The material subjected to incremental forming fails by fracture. Although damage models have been used to correlate the failure in incremental forming, a detailed understanding of the failure mechanism spanning strain paths is not clear yet. In this work, three parts with varied shapes (hybrid five lobe, pyramid and variable wall angle conical frustum (VWACF)) were developed using ISF to cover a range of possible strain paths. The failure is predicted using established uncoupled phenomenological damage models. Damage models were calibrated for AA1050 aluminium sheet by the method of inverse approach using carefully designed tensile tests and FE simulations. Three different damage models were implemented as user subroutine in commercial software code, ABAQUS/Explicit and the results predicted were compared. The linear damage accumulation used to develop fracture locus under monotonic loading could not predict the failure limit in a benchmark single groove test. Therefore a non linear damage accumulation rule (NLDA) is implemented to simulate ISF. The parameters of the NLDA were calibrated from the single groove test. The fracture forming limits during ISF was established using circular grid analysis near the failure zone of the formed part. A good agreement can be found between the experimental observations and numerical predictions for fracture location and part height. It was observed that the overall predictive capability of Hosford Coulomb (HC) damage model is better among three damage models investigated for the given range of loading conditions. However all the three models under-predicted the experimental fracture strain measured in ISF. The possible explanation for the discrepancy is explored.

Convolutional neural networks for prediction of geometrical errors in incremental sheet metal forming

Convolutional neural networks for prediction of geometrical errors in incremental sheet metal forming