scholarly journals A Mixed Double-Sided Incremental Forming Toolpath Strategy for Improved Geometric Accuracy

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Zixuan Zhang ◽  
Huaqing Ren ◽  
Rui Xu ◽  
Newell Moser ◽  
Jacob Smith ◽  
...  
Keyword(s):  
Incremental Forming ◽  
Sheet Forming ◽  
Geometric Accuracy ◽  
Forming Process ◽  
Process Flexibility ◽  
Tool Positioning ◽  
Toolpath Planning ◽  
Forming Parameters ◽  
Planning Strategies ◽  
Dieless Forming

Double-sided incremental forming (DSIF) is a relatively new dieless forming process which uses two hemispherical ended tools, one on each side of the sheet, moving along a predefined trajectory to locally deform a peripherally clamped sheet of metal. DSIF provides greater process flexibility, higher formability, and eliminates the tooling cost when compared to conventional sheet forming processes. While DSIF provides much improved geometric accuracy compared to other incremental forming processes, current toolpath planning strategies suffer from long forming times. A novel mixed double-sided incremental forming (MDSIF) toolpath strategy is proposed in the present study. It simultaneously reduces the total forming time by half while preserving the best currently achievable geometric accuracy. The effect of the forming parameters, i.e., of the incremental depth and of tool positioning on the geometric accuracy of the parts formed with MDSIF was investigated and compared to those formed by traditional DSIF strategies.

A Mixed Toolpath Strategy for Improved Geometric Accuracy and Higher Throughput in Double-Sided Incremental Forming

2014 ◽  
Author(s):  
Rui Xu ◽  
Huaqing Ren ◽  
Zixuan Zhang ◽  
Rajiv Malhotra ◽  
Jian Cao
Keyword(s):  
Incremental Forming ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Geometric Accuracy ◽  
Recent Past ◽  
Forming Process ◽  
Process Flexibility ◽  
Formed Part ◽  
Future Work

Incremental sheet forming has attracted considerable attention in the recent past due to advantages that include high process flexibility and higher formability as compared to conventional forming processes. However, attaining required geometric accuracy of the formed part is one of the major issues plaguing this process. The Double-Sided Incremental Forming process has emerged as a potential process variant which can preserve the process flexibility while maintaining required geometric accuracy. This paper investigates a mixed toolpath for Double-Sided Incremental Forming which is able to simultaneously achieve good geometric accuracy and higher throughput than is currently possible. The geometries of parts formed using the mixed toolpath strategy are compared to the desired geometry. Furthermore, an examination of the forming forces is used to uncover the reasons for experimentally observed trends. Future work in this area is also discussed.

Effects of Tool Deflection in Accumulated Double-Sided Incremental Forming Regarding Part Geometry

2016 ◽  
Author(s):  
Huaqing Ren ◽  
Newell Moser ◽  
Zixuan Zhang ◽  
Kornel F. Ehmann ◽  
Jian Cao
Keyword(s):  
Sheet Metal ◽  
Relative Position ◽  
Capital Investment ◽  
Incremental Forming ◽  
Position Angle ◽  
Tool Deflection ◽  
Geometric Accuracy ◽  
Localized Deformation ◽  
Forming Process ◽  
Part Geometry

Incremental forming is a flexible dieless forming process. In incremental forming, the metal sheet is clamped around its periphery. One or multiple generic stylus-type tools move along a predefined toolpath, incrementally deforming the sheet metal into a final, freeform shape. Compared with the traditional sheet metal forming process, the incremental forming process is more flexible, energy efficient and cost effective due to lower capital investment related to tooling. However, maintaining tight geometric tolerances in incremental formed parts can be a challenge. Specifically, undesired global bending is usually induced near the region between the tools and fixture resulting in a compromise in geometric accuracy. To address this issue, Accumulated Double-Sided Incremental Forming (ADSIF) is proposed, which utilizes two tools on both sides of the metal to better achieve localized deformation while simultaneously constraining global bending outside the forming area. Moreover, in ADSIF, the two tools are moving from inward to outward, and thus the tools are always forming virgin material and so as to limit forces on the already-formed part. Thus, ADSIF has a higher potential to achieve the desired geometry. Nevertheless, tool deflection due to machine compliance is still an issue that can have a considerable effect on geometric accuracy. In this work, the effect of tool deflection related to part geometry is studied for the ADSIF process. The nature of using two tools, rather than one, in ADSIF inherently implies that relative tool position is a critical process parameter. It is the region near these two tools where local squeezing and bending of the sheet occurs, the primary modes of deformation found in ADSIF. The change of relative tool positions (i.e., tool gap and relative position angle) are studied in detail by first developing an analytical model. It is concluded that the tool gap will be enlarged under the influence of tool compliance while the relative position angle is less affected. Additionally, a finite element simulation capable of modeling tool deflection is established. The comparison between the simulation results using rigid tools and deformable ones clearly demonstrated the significant influence of tool compliance on part geometry. Lastly, an axisymmetric part with varying wall angles was formed, and it was confirmed that ADSIF demonstrates improved geometry accuracy compared with conventional Double-Sided Incremental Forming.

Comparison of the Geometric Accuracy by DSIF Toolpath with SPIF Toolpath

2014 ◽  
Vol 494-495 ◽  
pp. 497-501 ◽  
Author(s):  
Jin Han Wu ◽  
Qiu Cheng Wang
Keyword(s):  
Incremental Forming ◽  
Single Point ◽  
Metal Sheet ◽  
Single Point Incremental Forming ◽  
Geometric Accuracy ◽  
Forming Process ◽  
Forming Accuracy ◽  
Finite Method

As there is no sufficient support between the single moving tool and fixture, the formed metal sheet is easy to bend in single point incremental forming (SPIF). Double sided incremental forming (DSIF) is proposed in which two tools are used on each side of the sheet to improve the components forming accuracy. Element finite method is introduced to simulate the forming process with both DSIF and SPIF toolpaths and the component geometric accuracies are compared. The simulation result shows the DSIF toolpaths can obtain better geometric accuracy than SPIF.

Development of Tool Path Correction Algorithm in Incremental Sheet Forming

2014 ◽  
Vol 622-623 ◽  
pp. 382-389 ◽  
Author(s):  
Antonio Fiorentino ◽  
G.C. Feriti ◽  
Elisabetta Ceretti ◽  
C . Giardini ◽  
C.M.G. Bort ◽  
...  
Keyword(s):  
Tool Path ◽  
Error Distribution ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Correction Algorithm ◽  
Forming Process ◽  
Part Geometry ◽  
Toolpath Planning ◽  
The Difference ◽  
Tool Path Correction

The problem of obtaining sound parts by Incremental Sheet Forming is still a relevant issue, despite the numerous efforts spent in improving the toolpath planning of the deforming punch in order to compensate for the dimensional and geometrical part errors related to springback and punch movement. Usually, the toolpath generation strategy takes into account the variation of the toolpath itself for obtaining the desired final part with reduced geometrical errors. In the present paper, a correction algorithm is used to iteratively correct the part geometry on the basis of the measured parts and on the calculation of the error defined as the difference between the actual and the nominal part geometries. In practice, the part geometry is used to generate a first trial toolpath, and the form error distribution of the resulting part is used for modifying the nominal part geometry and, then, generating a new, improved toolpath. This procedure gets iterated until the error distribution becomes less than a specified value, corresponding to the desired part tolerance. The correction algorithm was implemented in software and used with the results of FEM simulations. In particular, with few iterations it was possible to reduce the geometrical error to less than 0.4 mm in the Incremental Sheet Forming process of an Al asymmetric part, with a resulting accuracy good enough for both prototyping and production processes.

scholarly journals Cranial Reconstruction Using Double Side Incremental Forming

2015 ◽  
Vol 639 ◽  
pp. 535-542 ◽  
Author(s):  
Bin Lu ◽  
Dong Kai Xu ◽  
Run Zhe Liu ◽  
Heng An Ou ◽  
Hui Long ◽  
...  
Keyword(s):  
Tool Path ◽  
Incremental Forming ◽  
Thickness Distribution ◽  
Single Point ◽  
Pure Titanium ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Geometric Accuracy ◽  
Backing Plate ◽  
Cranial Implant

Incremental sheet forming (ISF) is a highly versatile and flexible process for rapid manufacturing of complex sheet metal parts. Comparing to conventional sheet forming processes, ISF is of a clear advantage in manufacturing small batch or customized products such as cranial implant. Although effort on cranial reconstruction by using incremental sheet forming approach has been made in recent years, research has been mostly based on the single point incremental forming (SPIF) strategy and there are still considerable technical challenges for achieving better geometric accuracy, thickness distribution and complex cranial shape. In addition, the use of a backing plate or supporting die reduces the process flexibility and increases the cost. To overcome these limitations, double side incremental sheet forming (DSIF) process is employed for forming Grade 1 pure titanium sheet by using different toolpath strategies. The geometric accuracy and thickness distribution of the final part are evaluated so the optimized tool path strategies are developed. This leads to an assessment of the DSIF based approach for the application in cranial reconstruction.

Brass 70/30 and Incremental Sheet Forming Process

2013 ◽  
Vol 554-557 ◽  
pp. 1419-1431 ◽  
Author(s):  
Daniel Fritzen ◽  
Anderson Daleffe ◽  
Jovani Castelan ◽  
Lirio Schaeffer
Keyword(s):  
Incremental Forming ◽  
Single Point ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Cnc Machining ◽  
Forming Process ◽  
Wall Angle ◽  
Machining Center ◽  
Cad Cam ◽  
Cnc Machining Center

This work addresses through bibliographies and experiments the behavior of sheet brass 70/30 for Incremental Sheet Forming process - ISF, based on the parameters: wall angle (), step vertical (ΔZ) strategy and the way the tool. Experiments based on the method called Single Point Incremental Forming - SPIF. For execution of practical tests, we used the resources: software CAD / CAM, CNC machining center with three axles, matrix incremental, incremental forming tool and a device press sheets. Furthermore, measurement was made of the true deformation () and thickness (s1). Practical tests have shown that the spiral machining strategy yielded a greater wall angle, compared to the conventional strategy outline.

Experimental Investigation of a Backing Sheet Stiffener in Incremental Forming of Polycarbonate

2019 ◽  
Author(s):  
Tyler J. Grimm ◽  
Shubhamkar Kulkarni ◽  
Laine Mears ◽  
Gregory Mocko
Keyword(s):  
Incremental Forming ◽  
Elastic Recovery ◽  
Single Point ◽  
Plate Thickness ◽  
Steel Plates ◽  
Forming Process ◽  
Geometrical Accuracy ◽  
Backing Plate ◽  
Reduction Methods ◽  
Dieless Forming

Abstract Single point incremental forming (SPIF) is a dieless forming process for sheet materials. This process forms materials with a hemispherical forming tool which locally deforms the sheet at incremental depths. The freeform nature of this process promises significant efficiency improvements within small and medium volume industries where stamping is traditionally used. However, several drawbacks currently inhibit its widespread use. One of these drawbacks is springback or elastic recovery resulting in reduced geometrical accuracy. An existing approach to counter this involves using a dedicated backing die, increasing the cost of the forming apparatus and the overall energy input per part. Other springback reduction methods involve the direct addition of energy to the workpiece through electrical or heat input. This study investigates the use of sacrificial steel blanks as backing dies for incremental forming of polycarbonate sheets, to overcome the loss in geometrical accuracy affiliated with forming geometries with a relatively large distance between the geometry periphery and the clamped edge. The blanks were not bound to each other, but rather clamped along their edges. In this study, polycarbonate blanks were tested using a three-factorial design of experiments, with relative plate thicknesses of 0.4, 0.5, and 0.6, and wall angles of 15°, 30°, 45°, and 60° as independent factors. The test geometry used was a straight walled pyramid with a square base. Using the backing sheet, a reduction in the springback was observed, demonstrating the effectiveness of sacrificial backing blanks. Particularly, the ‘pillow effect’ at the base of the geometry was reduced. This is attributed to the higher stiffness of the steel plates, increasing the plastic strain on the polycarbonate. However, the formability is found to decrease for higher values of the backing plate thickness due to premature steel failure. In future studies, this work will be expanded to include additional thickness ratios, geometries, toolpath types, step sizes and materials to form a more complete trend.

Review of the effect of process parameters on performance measures in the incremental sheet forming process

2020 ◽  
pp. 095440542096121
Author(s):  
Ashish Gohil ◽  
Bharat Modi
Keyword(s):  
Process Parameters ◽  
Metal Forming ◽  
Lead Time ◽  
Incremental Forming ◽  
Low Cost ◽  
Research Work ◽  
Sheet Forming ◽  
Commercial Production ◽  
Incremental Sheet Forming ◽  
Forming Process

Incremental sheet forming process has developed the interest of researchers in the field of sheet metal forming due to high formability and capability to produce prototypes of new products at low cost and minimum lead time. Research work is going on in various front to enhance the process capabilities so that it can be explored for commercial production. In this article, progress and recent development in the field of incremental forming has been reviewed and presented for the benefit of practicing engineers and industry. The effect of various process parameters on the performance of the process have been summarized in this paper. Moreover, the issues which need attention are discussed towards the conclusion of this paper.

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