Claims:We claim:

1. A Variable Surface Sheet-Blank holder mechanism for incremental Sheet Forming (ISF), said mechanism comprising:

(a) one or more Variable Support Surface/s (VSS) formed of one or more Local Support Surface/s (LSS) of power pin (PP) grids as sheet blank holder;

(b) said Variable Support Surface (VSS) firmly mounted on the pedestal of an ISF machine;

(c) said blank holder formed by operating the power pins (PP) of said Local Support Surface/s (LSS) in a controlled manner by means of the Electronic Control Unit (ECU) of said ISF machine;

(d) one or more Single-Point Incremental Sheet Forming (SP-ISF) tool/s (T) mounted on a robotic arm of said ISF machine for performing Single-Point Incremental Sheet Forming (SP-ISF) or Double-Point Incremental Sheet Forming (DSP-ISF) process on a sheet material blank;

(e) a plurality of slots configured about said mechanism for lateral retraction of one or more of said LSS of power pin (PP) grids therein and predefined by said ECU to create working space within said VSS for operating said Incremental Sheet Forming tool (T) therein;

wherein each of said Local Support Surface/s (LSS) of power pin grids of said VSS are pre-configured by said ECU according to the targeted profile of the sheet component to be manufactured by said Incremental Sheet Forming (ISF) process, said LSS of power pin (PP) grids firmly holding said sheet material blank in any two directions in a three-dimensional space to conduct said ISF process in the remaining third direction of said three-dimensional space.

2. Variable Surface Sheet-Blank holder mechanism as claimed in claim 1, wherein said VSS comprises two of said LSS comprising of a plurality of power pin (PP) grids each, to firmly hold said sheet material blank therebetween to conduct said ISF process for obtaining the profile/s and/or feature/s on said sheet material blank of said targeted sheet component.

3. Variable Surface Sheet-Blank holder mechanism as claimed in claim 2, wherein one of said LSS each is disposed on either side of the sheet material blank to be worked upon on said pre-configured Local Support Surface/s (LSS) of power pin grids to obtain said profile/s and/or feature/s.

4. Variable Surface Sheet-Blank holder mechanism as claimed in claim 2, wherein said LSS of power pin (PP) grids are configured identical for facilitating the removal and/or addition thereof within said VSS, based on the location of each profile and/or feature of said targeted sheet component.

5. Variable Surface Sheet-Blank holder mechanism as claimed in claim 1, wherein each of said power pin (PP) of said LSS of power pin (PP) grids is moveable along a predefined direction by a respective hydraulically or pneumatically or solenoids operated pin cylinder and controlled by said ECU.

6. Variable Surface Sheet-Blank holder mechanism as claimed in claim 1, wherein each of said LSS comprises m x n number of identical power pin grids, in which ‘m’ is the number of power pin grids in longitudinal direction and ‘n’ is the number of power pin grids in transverse direction, and each power pin grid includes ‘p’ number of power pins (PP).

7. Variable Surface Sheet-Blank holder mechanism as claimed in claim 1, wherein said Incremental Sheet Forming tool (T) is operable at any position and/or at any angle in said three-dimensional space in the surroundings of said tool (T).

8. Variable Surface Sheet-Blank holder mechanism as claimed in claim 1, wherein said Variable Support Surface (VSS) is configured as VSS (200) comprising a single Local LSS (200) having a plurality of power pin (PP) grids.

9. Variable Surface Sheet-Blank holder mechanism as claimed in claim 8, wherein said sheet material blank (10) is firmly supported on said Local LSS (200) to conduct Single-Point Incremental Sheet Forming (SP-ISF) process by using one of said Incremental Sheet Forming tool/s (T).

10. Variable Surface Sheet-Blank holder mechanism as claimed in claim 9, wherein one of more of said power pin (PP) grids of said Local LSS (200) predefined by said ECU is/are laterally retracted in corresponding slot/s provided about said mechanism to conduct Single-Point Incremental Sheet Forming (SP-ISF) process by using one of said Incremental Sheet Forming tool/s (T) in the working space so created.

11. Variable Surface Sheet-Blank holder mechanism as claimed in claim 1, wherein said Variable Support Surface (VSS) is configured as VSS (200) comprising an upper Local LSS (210) and a lower Local LSS (220), each LSS (210, 220) having a plurality of power pin (PP) grids separated by said plane (S-S) disposed therebetween.

12. Variable Surface Sheet-Blank holder mechanism as claimed in claim 11, wherein one of more of said power pin (PP) grids of said Local LSS (210) or LSS (220) predefined by said ECU is/are laterally retracted in corresponding slot/s provided about said mechanism to conduct a Single-Point Incremental Sheet Forming (SP-ISF) process by using one of said Incremental Sheet Forming tool/s (T).

13. Variable Surface Sheet-Blank holder mechanism as claimed in claim 12, wherein one or more of said power pin (PP) grids of said Local LSS (210) or LSS (220) predefined by said ECU is/are laterally retracted in corresponding slot/s provided about said mechanism to conduct a Single-Point Incremental Sheet Forming (SP-ISF) process by using one of said Incremental Sheet Forming tool/s (T) in the working space so created.

14. Variable Surface Sheet-Blank holder mechanism as claimed in claim 11, wherein one or more of said power pin (PP) grids of said Local LSS (210) and LSS (220) facing each other on either side of said plane (S-S) predefined by said ECU is/are laterally retracted in corresponding slot/s provided about said mechanism to conduct a Double-Point Incremental Sheet Forming (DP-ISF) process by using one of said Incremental Sheet Forming tools (T) from either side of said plane (S-S) in the respective working spaces so created.

15. Variable Surface Sheet-Blank holder mechanism as claimed in claim 1, wherein the packing density of said power pins (PP) in said LSS is predefined by said ECU depending on thickness and/or characteristics and/or mechanical properties of said sheet material as well as based on the various profiles/features to be formed therein.

16. Incremental sheet forming (ISF) process (P) performed by using said Variable Surface Sheet-Blank holder mechanism as claimed in claims 1-15, wherein said process comprises the steps of:

(i) pre-configuring in said ECU, all profile/s and/or feature/s sequentially to be made on said sheet material blank for obtaining a targeted sheet component;

(ii) removing and/or adding one or more power pin grids from the respective Local Support Surface/s (LSS) of variable support surface (VSS) to create working space for the respective Incremental Sheet Forming tool/s (T) to form each respective profile and/or feature to be obtained on said sheet material blank;

(iii) firmly holding said sheet material blank on or between said Local Support Surface/s (LSS) for conducting said Incremental Sheet Forming (ISF) process;

(iv) moving said Incremental Sheet Forming tool/s (T) multiple times on an unfinished surface (UFs) of said sheet material blank for making a respective pre-configured profile and/or feature of said targeted sheet component thereon; and

(v) repeating the process steps (ii) to (iv) for each profile and/or feature to be made on said sheet material blank to obtain said targeted sheet component.

17. Incremental sheet forming (ISF) process (P) as claimed in claim 16, wherein said Incremental Sheet Forming tool (T) is disposed on one side of said plane (S-S)for conducting a Single-Point Incremental Sheet Forming (SP-ISF) process in the working space created on the opposite side of said plane (S-S).

18. Incremental sheet forming (ISF) process (P) as claimed in claim 16, wherein one of said Incremental Sheet Forming tool/s (T) each disposed on either side of said plane (S-S) for conducting a Double-Point Incremental Sheet Forming (DP-ISF) process in the respective working spaces created on either side of said plane (S-S).

19. Incremental sheet forming (ISF) process (P) as claimed in claim 18, wherein said Incremental Sheet Forming tool/s (T) disposed on either side of said plane (S-S) are aligned offset by a predefined distance to facilitate the flow of sheet material on moving said ISF tools (T) in a coordinated manner, while conducting said Double-Point Incremental Sheet Forming (DP-ISF) process.

Dated this 17th day of December 2019.

Digitally Signed.

(SANJAY KESHARWANI)
APPLICANT’S PATENT AGENT
REGN. NO. IN/PA-2043. , Description:FIELD OF INVENTION

The present invention relates to an improved sheet forming process for manufacturing sheet material components, predominantly automotive components. In particular, the present invention relates to an improved process for manufacturing automotive components for incremental sheet forming process by using single probe or multiple probes. More particularly, the present invention relates to a Variable Surface Sheet-Blank holder mechanism for manufacturing automotive components having several features by using a single point/probe incremental sheet forming process (SP-ISF) or a double point/probe process (DP-ISF) performed on the sheet material blank supported on variable surface/s formed of power pin grid/s.

BACKGROUND OF THE INVENTION

Incremental sheet forming (ISF) is a sheet forming process without using conventional forming dies. Generally, ISF involves forming sheet components by using a round tipped tool, e.g. having a diameter of 5-20 mm, attached to CNC machine, milling machine, robot arm or the like. This tool makes indentations on sheets in the first stage and follows a contour of the targeted profile for the component to be manufactured therefrom. In a second stage or subsequent stages, this tool makes further indentations to form the next contour of the targeted profile in this indented sheet component and continues to perform such further indentations until the final targeted profile of this sheet component is obtained. Incremental sheet forming process can also be applied to polymer and composite sheets too.

The term Single Point Incremental Forming (SPIF) is used when the opposite side of the sheet is not supported and Two Point Incremental Forming (TPIF) when another tool probe supports from other side of sheet.
Another classification is based on the relative movement of the sheet and forming tool therefor. For example, in a positive ISF system, the sheet is deformed to make a protrusion therein by lowering the forming tool incrementally on a protruding die or blank hold fixture.

Whereas, in a negative ISF system, the sheet is deformed to make a cavity therein by holding the sheet on a static fixture. ISF involves a pin or tool having spherical tip to perform highly localized material deformation in a certain portion of the sheet being worked on. Due to the simplicity of this pin, both symmetrical and asymmetrical profiles can be easily made in sheets in a cost-effective manner by using an ISF process.

ABBREVIATIONS USED:

ISF : Incremental Sheet Forming
SP-ISF : Single-Point/Probe Incremental Sheet Forming
DP-ISF : Double-Point/Probe Incremental Sheet Forming
LSU : Local Support Unit
VSS : Variable Support Surface

Since ISF process is normally completely controlled by CNC processes, it does not require any die that is necessary in conventional sheet metal forming.

This substantially reduces the cost per component due to elimination of dies and punches and also increases the turnaround time for low production runs by dispensing with die manufacture. ISF adds value by saving huge tooling cost and few months’ time required for the development of prototype parts. However, for high production runs the time and cost to produce a die is compensated by the higher per component speed and lower per component cost.

Several studies have recognized that the formability of metal materials under the localized deformation provided by incremental sheet forming is better than in conventional deep metal drawing process. However, there is a reduced accuracy with the components produced by ISF processes.

ISF uses a three-dimensional arrangement, in which sheet is firmly held in X-Y plane using blank holder. This sheet is formed, as the ISF tool is free to move in this X-Y plane and to complete the tool path after each small step along Z-direction in a coordinated manner to form the desired profile developed and pre-stored by CAD.

DISADVANTAGES OF THE PRIOR ART

However, the disadvantage with this ISF process is that a single component having different profiles cannot be made by this process, because after making a first profile in the component, making another profile is impossible, as this the first profile already made therein, would be damaged during subsequent ISF operation on the same sheet with first profile made therein.

Therefore, there is an existing need for an improve process for carrying out incremental sheet forming (ISF) and a system for carrying out incremental sheet forming, which can overcome the aforesaid limitation of the conventional ISF process performed on a component having multiple profiles and which is made of sheet material, preferably but not limited to metal sheets.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide an improved incremental sheet forming process for making a plurality of profiles on a component made of sheet material.

Another object of the present invention is to provide an improved incremental sheet forming system for making a plurality of profiles on a component made of sheet material.

Still another object of the present invention is to provide an improved incremental sheet forming process for making a plurality of profiles at different locations on a component made of sheet material.

Yet another object of the present invention is to provide a Variable Surface Sheet-blank holder mechanism for performing incremental sheet forming process for making a plurality of profiles at different locations on a component made of sheet material.

A further object of the present invention is to provide a Variable Surface Sheet-blank holder mechanism for performing incremental sheet forming process to make profiles at different locations by using single-point forming (SP-ISF) tool.

Yet another object of the present invention is to provide a Variable Surface Sheet-blank holder mechanism for performing incremental sheet forming system to make profile/s and/or feature/s at different locations by using a single-point (SP-ISF) tool.

A further object of the present invention is to provide a Variable Surface Sheet-blank holder mechanism for performing incremental sheet forming system to make profile/s and/or feature/s at different locations by using a double-point (DP-ISF) tool.

A still further object of the present invention is to provide a Variable Surface Sheet-blank holder mechanism for performing incremental sheet forming system to make profile/s and/or feature/s at different locations by using a double- point (DP-ISF) forming tool.

A yet further object of the present invention is to provide a Variable Surface Sheet-blank holder mechanism for performing incremental sheet forming system to make profile/s and/or feature/s by using a Local Support Surface (LSS) made of a variable grid of pins.

These and other objects and advantages of the present invention will become more apparent from the following description, when read with the accompanying figures of drawing, which are however not intended to limit the scope of the present invention in any way.

DESCRIPTION OF THE INVENTION

The present invention comprises a variable surface sheet-blank holder mechanism configured to be changed by attachment or detachment of a grid of local support pins. These pins are preferably grouped in grids of same or different numbers.

Further, the present invention preferably offers several Local Support Surface (LSS) as the sheet blank holder formed of a plurality of power pin grids and which can be attached to or detached from the VSS for facilitating ISF forming in specific region of the sheet blank for forming desired profile/ and/or feature/s therein. Since sheet is firmly held in any two directions (e.g. X, Y directions), ISF process is performed in the remaining direction (e.g. Z direction) and the desired pin grids can be slid along X or Y direction to facilitate the sheet to deform along Z direction during this process.

More preferably, the present invention offers a VSS formed of a plurality of Local Support Surface (LSS) which are disposed on either side of the sheet blank being worked upon. For example, one LSS is disposed above the sheet to be worked on and another LSS is disposed below sheet blank to be worked on.

Still more preferably, Local Support Surface (LSS) are configured identical to be removed or added, based on the location of the desired profile/s and/or feature/s to be made during the ISF forming process on the sheet blank.

Yet more preferably, Local Support Surface (LSS) can be used as local Variable Support Surface for SP-ISF process as well as for DP-ISF process.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided Variable Surface Sheet-Blank holder mechanism for Incremental Sheet Forming process, the mechanism comprising:

(a) one or more Variable Support Surface/s formed of one or more Local Support Surface/s (LSS) of power pin grids as sheet blank holder;

(b) the Variable Support Surface (VSS) firmly mounted on the pedestal of the ISF machine;

(c) the blank holder mechanism formed by operating the power pins (PP) of said Local Support Surface/s (LSS) in a controlled manner by means of the Electronic Control Unit (ECU) of said ISF machine;

(d) one or more Single-Point Incremental Sheet Forming (SP-ISF) tool/s mounted on a robotic arm of the ISF machine for performing the Single-Point Incremental Sheet Forming (SP-ISF) or the DSP-ISF process on a sheet material blank;

(e) a plurality of slots configured about the mechanism for lateral retraction of one or more of the LSS of power pin grids therein and predefined by the ECU to create working space within the VSS for operating the Incremental Sheet Forming tool therein;

wherein each of the Local Support Surface/s of power pin grids of the VSS are pre-configured by the ECU according to the targeted profile of the sheet component to be manufactured by the ISF process, the LSS of power pin grids firmly holding the sheet material blank in any two directions in a three-dimensional space to conduct the ISF process in the remaining third direction of the three-dimensional space.

Typically, the VSS comprises two of the LSS comprising of a plurality of power pin grids each to firmly hold the sheet material blank therebetween to conduct the ISF process for obtaining the profile/s and/or feature/s on the sheet material blank of the targeted sheet component.

Typically, one of the LSS each is disposed on either side of the sheet material blank to be worked upon on the pre-configured Local Support Surface/s (LSS) of power pin grids to obtain the profile/s and/or feature/s.

Typically, the LSS of power pin grids are configured identical for facilitating the removal and/or addition thereof within the VSS, based on the location of each profile and/or feature of the targeted sheet component.

Typically, each of the power pin of the LSS of power pin grids is moveable along a predefined direction by a respective hydraulically or pneumatically or solenoids operated pin cylinder and controlled by the ECU.
Typically, each of the LSS comprises m x n number of identical power pin grids, in which ‘m’ is the number of power pin grids in longitudinal direction and ‘n’ is the number of power pin grids in transverse direction, and each power pin grid includes ‘p’ number of power pins.

Typically, the Incremental Sheet Forming tool is operable at any position and/or at any angle in three-dimensional space in the surroundings of the tool.

In an embodiment of the present invention, there is provided an ISF machine, in which VSS comprises single Local LSS having a plurality of power pin grids.

Typically, the sheet material blank is firmly supported on the LSS to conduct SP-ISF process by using one of the Incremental Sheet Forming tool/s.

Typically, one of more of the power pin grids of the LSS predefined by the ECU is/are laterally retracted in corresponding slot/s provided about the mechanism to conduct SP-ISF process by using one of the Incremental Sheet Forming tool/s in the working space so created.

In another embodiment of the present invention, there is provided an ISF machine, in which the VSS comprises an upper LSS and a lower LSS, each LSS having a plurality of power pin grids separated by the plane disposed therebetween.

Typically, one of more of the power pin grids of either LSS predefined by the ECU is/are laterally retracted in corresponding slot/s provided about the mechanism to conduct SP-ISF process by using one of the Incremental Sheet Forming tool/s.

Typically, one of more of the power pin ids of either LSS predefined by the ECU is/are laterally retracted in corresponding slot/s provided about the mechanism to conduct SP-ISF process by using one of the Incremental Sheet Forming tool/s in the working space so created.

Typically, one of more of the power pin grids of the LSS facing each other on either side of the plane predefined by the ECU is/are laterally retracted in corresponding slot/s provided about the mechanism to conduct a DP-ISF process by using one of the Incremental Sheet Forming tools from either side of the plane in the respective working spaces so created.

Typically, the packing density of the power pins in the LSS is predefined by the ECU depending on thickness and/or characteristics and/or mechanical properties of the sheet material as well as based on the various profiles/features to be formed therein.

In one embodiment of the present invention, there is also provided an ISF process performed on the aforesaid Variable Surface Sheet-Blank holder mechanism, in which the process comprises the steps of:

(i) pre-configuring in the ECU, all profile/s and/or feature/s sequentially to be made on the sheet material blank for obtaining a targeted sheet component;

(ii) removing and/or adding one or more power pin grids from the respective LSS of the VSS to create working space for the respective Incremental Sheet Forming tool/s to form each respective profile and/or feature to be obtained on the sheet material blank;

(iii) firmly holding the sheet material blank on or between the LSS for conducting the ISF process;

(iv) moving the Incremental Sheet Forming tool/s multiple times on an unfinished surface of the sheet material blank for making a respective pre-configured profile and/or feature of the targeted sheet component thereon;

(v) repeating the process steps (ii) to (iv) for each profile and/or feature to be made on the sheet material blank to obtain the targeted sheet component.

Typically, the Incremental Sheet Forming tool is disposed on one side of the plane for conducting a SP-ISF process in the working space created on the opposite side of the plane.

Typically, one of the Incremental Sheet Forming tool/s each disposed on either side of the plane for conducting a DP-ISF process in the respective working spaces created on either side of the plane.

Typically, the Incremental Sheet Forming tool/s disposed on either side of the plane (S-S) are aligned offset by a predefined distance to facilitate the flow of sheet material on moving the ISF tools in a coordinated manner, while conducting the DP-ISF process.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described in the following with reference to the accompanying drawings.

Figure 1 shows a perspective view of an exemplary component made from a planar sheet material by using the improved ISF process P carried out on the ISF machine M configured in accordance with the present invention.

Figure 2 shows another perspective view of the component shown in Figure 1 after rotation thereof towards right by 900.
Figure 3a shows a perspective view of the Variable Surface Sheet-blank holder mechanism consisting of upper and lower Local Support Surface (LSS) units, each consisting of LSS power pin grids to be used as blank holder of the ISF machine configured in accordance with the present invention for performing SP-ISF or DP-ISF process P to make the component.

Figure 3b shows a VSS mechanism configured in accordance with the present invention and provided with a single (lower) local support surface (LSS) firmly supported on base frame installed on a pedestal mounted on ISF machine base for carrying out the ISF process.

Figure 4 shows first feature of the component shown in Figure 1 highlighted to be initially made in the first series of process steps described further below.

Figure 5 shows a sequential process chart as well as respective positions of Single-Point/Probe (SP-ISF) tool used for performing improved Single-Point/Probe (SP-ISF) ISF process P developed in accordance with the present invention, to obtain the first feature formed in original sheet blank.

Figure 6a shows the first step obtained in final step thereof with the tool in a position on initially formed sheet before being withdrawn from this first feature formed therein and ready to be moved away before proceeding to next ISF forming operation in component.

Figure 6b shows an enlarged view of the working area (Fig. 3b) in the vicinity of the single-point tool tip while performing the improved ISF process configured in accordance with the present invention. The variable surface sheet-blank holder mechanism made of local support surface (LSS) having power pin grids pre-configured by ECU of ISF machine before commencing this SP-ISF process are also shown.

Figure 7 shows the second feature of component shown in Fig. 1 highlighted in the sheet to be obtained during the subsequent series of process steps to be performed later.

Figure 8 shows a perspective view of VSS of Fig. 3 arranged for making the second feature of the component highlighted in Fig. 7 in the initially formed sheet held between upper and lower LSS units and obtaining a subsequently formed sheet with the first and second features by using an SP-ISF tool.

Figure 9 shows the second feature obtained in final step and SP-ISF tool in final position on sheet before being withdrawn from this second feature. The SP-ISF tool is ready to be moved away before proceeding to the next ISF forming operation to form a third feature with hole and made in the above formed sheet of the component after automatically (algorithm driven) sliding LSS units for adjustment thereof for forming the next feature by using ISF tool.

Figure 10 shows another sequential process chart as well as respective positions of DP-ISF tools used for performing improved Double-Point/Probe (DP-ISF) process 2P developed in accordance with the present invention, to obtain the same first feature formed in original sheet blank shown in Fig. 1.

Figure 11 shows a perspective view of the arrangement of making the first feature obtained in final step of above-described DP-ISF process 2P, with tools now shown in a position on the initially formed sheet with the first feature completely formed therein, before DP-ISF tools being withdrawal therefrom and moved away and prior to perform the next series of steps for forming the second feature of the component after automatically (algorithm driven) sliding the LSS units for adjustment for forming the next feature to be subsequently formed on this initially formed sheet during this DP-ISF process 2P.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following a Variable Surface Sheet-blank holder mechanism for performing an incremental sheet forming (ISF) by using grids of locally supporting surface (LSS) of power pins configured in accordance with the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention.

Figure 1 shows a perspective view of an exemplary component 100 made from a planar sheet material 10 by using the SP-ISF having Variable Support Surface (VSS) with multiple grids of locally supporting surface (LSS) of power pins and configured in accordance with the present invention and supported on ISF machine M. For example, component 100 includes a first feature 12 formed in sheet blank 10 as a two-step depression and two trapezoidal protrusions 20; 30 (with a hole 32 formed therein) and raised above the plane of the original sheet blank 10 and two depressions 40 (more clearly visible in Figure 2) formed by pressing previously incrementally formed sheet below original plane of sheet blank 10.

Figure 2 shows another perspective view of the component 100 shown in Figure 1 after rotation thereof towards right by 900. In addition to features 12; 20; 30, 32; and 40 of Fig.1. Depressions 40 are made by bending sheet blank 10 about bending lines E-F and G-H and disposing the portions of depressions 40 in different planes of component 100 as shown in this figure.

Figure 3a shows a perspective view of a typical VSS 200, consisting of an upper LSS unit 210 and a lower LSS unit 220, each of which e.g. consists of nine LSS power pin grids (only visible for upper LSS 210 here) marked as power pin grids 1, 2, 3, 4, 5, 6, 7,8 9. The number of LSS power pin grids and the packing density of power pins (PP) within a LSS power pin grid is selected based on the category of components to be formed by using this ISF process. This VSS 200 is used as a blank holder in the ISF machine (Fig. 3b) which is configured to make component 100 of Fig. 1 by using the improved SP-ISF and/or DP-ISF process developed in accordance with the present invention. Each LSS power pin grid units 1 to 9 disposed at the above and below the plane S-S (separating LSS units 210 and 220 in Fig. 5), consists of predefined equal number of power pins 230, 240. Sheet 10 is placed between LSS units 210 and 220 for performing ISF process P thereon, as discussed below. The respective power pins 230, 240 of upper and lower LSS units 210, 220 are axially aligned with each other precisely after proper installation of on these units 210, 220 placed on this ISF machine. These pins 230, 240 are axially moveable (vertically in directions d1, d2, d3, d4 as shown in figures 5, 8 and 10 shown here) by means of the individual actuating mechanisms provided and controlled by optimum tool path planning algorithm (Figure 6b), by means of which individual pin 230, 240 cane be moved to form the targeted variable support surface for making a specific features targeted in the process sequence, e.g. P1-P5 (Figure 5); process sequence P-7-P10 (Figure 8); and process sequence 2P1-2P5 (Figure 10) and so on.

Figure 3b shows a Variable Surface Sheet-blank holder mechanism configured for performing the improved ISF process developed in accordance with the present invention, on a VSS mechanism with a single (lower) local support surface LSS firmly supported on a base frame B, which is installed on a pedestal mounted on the base of machine M. The ISF machine M (not shown) includes a conventional robot arm R electronically operated and controlled by ECU provided thereof. An SP-ISF forming tool T having a tool tip Tt and rotating at high-speed (if required, else assume it not rotating) is made to travel in X-Y plane after each downward step pressed in Z-direction by the robotic arm R according to the profile of the LSS grid by vertically moving individual pins thereof and pre-configured by machine ECU based on CAD drawings pre-stored therein for making a targeted product, e.g. a component 10. Although, the embodiments shown and described herein are representing a vertical movement of power pins of typical LSS grid, it is not a limiting factor and the idea underlying this invention can be implemented to orient LSS grid with multiple power pins for moving these pins in any three-dimensional space disposed at any angle and accordingly, these LSS grids can be suitably mounted and installed to make multiple features of the components in a single setting of the SP-ISF tool adjusted by using the ISF machine ECU. It is also conceivable that like conventional SP-ISF or DP-ISF processes, the improved SP-ISF and/or DP-ISF tool configured in accordance with the invention is also adequately lubricated by continuously surrounding the tool tip Tt, by using appropriate coolant flow for causing a minimum friction between this tool tip Tt and sheet 10 during forming thereof on ISF machine.

Figure 4 shows first highlighted feature 12 of component 100 shown in Fig. 1 and which is to be initially made in a first series of process steps P1-P5 described below.

Figure 5 shows a sequential process chart as well as respective positions T1, T2, T3 of Single-Point/Probe (SP-ISF) tool T used for performing the improved Single-Point/Probe (SP-ISF) ISF process P developed in accordance with the present invention, to obtain first feature 12 formed in the original sheet blank 10. For example, feature 12 includes a stepped conical profile with a first step 12a and a second step 12b with a closed cup formed therein. As clearly visible here, sheet blank 10 is firmly held in the VSS mechanism 200 between the upper LSS unit 210 and the lower LSS 220 unit thereof and only power pin grid LSS 2 (Fig. 3a) is retracted from upper LSS unit 210 to create the working space for facilitating incremental sheet forming process P by tool T in the original sheet blank 10 by using this improved SP-ISF process P. This SP-ISF process starts at step P1. At next process step P2, tool T is automatically moved down to touch sheet blank 10 at position T1. In subsequent first pass at step P3, tool T is automatically moved further inwardly and downwardly by the ECU in a predefined manner to incrementally press down the material of sheet blank 10 to form the planar surface for forming (I) a first step 12a of targeted feature 12 and tool T stops at position T2. Now the corresponding support power pins of unit 220 are retracted according to the instruction given by the machine controller (ECU) based on pre-stored algorithm therein, for making the necessary support ready for making the next feature 12b. In subsequent second pass at step P4, tool T is automatically brought further inwards to a tool position T3 and automatically moved further inwardly and downwardly in a predefined manner to incrementally press down the material of planar surface of first step 12a for partially reforming (II) the same to obtain a second step 12b with a closed cup-like profile of targeted feature 12 in the initially formed sheet 10A. Since CAD drawings are already stored in the ECU of the ISF machine, e.g. a CNC machine, each and every feature (e.g. 12; 20; 30, 32; 40) of component can be accurately and quickly replicated sequentially, however without damaging the feature/s formed in the preceding improved ISF forming step/s.

Figure 6a shows the first step 12a obtained in final step P5, and tool T is in a position on initially formed sheet 10A before being withdrawn from first feature 12 formed therein and ready to be moved away before proceeding to next ISF forming operation in component 100, e.g. forming a second trapezoidal feature 20 (Fig. 1) subsequently in this initially formed sheet 10A.

Figure 6b shows an enlarged detailed view of the working area in the vicinity of tool tip Tt while performing the improved ISF process P developed in accordance with the present invention. Before commencing this SP-ISF process P, this variable surface sheet-blank holder mechanism consisting of at least one local support surface LSS constituted of one or more power pin grids pre-configured by the machine ECU, depending on the targeted profiles and/or features to be formed by the SP-ISF process P (Figs. 5, 8) or DP-ISP process 2P (Fig.10). Each power pin PP is moved in the predefined direction by means of pin cylinders operated hydraulically or pneumatically or even actuated by solenoids. Here, tip Tt of tool T is shown moving in the arrow direction Tm and leaves behind a finish formed profiled surface Fs made by this tool tip Tt moving ahead towards the unfinished sheet surface UFs yet to be worked on. Tool T requires a predefined number of turns or movements along unfinished sheet surface UFs for complete forming of each targeted feature of the component made by this improved SP-ISF process P or DP-ISF process 2P. It is to be noted that the packing density of power pins in LSS grid is predefined by the machine ECU depending on thickness and characteristics/mechanical properties of the sheet material as well as based on various profiles/features to be formed therein, by means of this improved ISF process P.

Figure 7 shows highlighted second feature 20 of component 100 shown in Fig.1 to be made in the above-described initially formed sheet 10A (Fig. 5-I) to obtain this subsequently sheet 10B (Fig. 5-II) formed with second feature 20 in the subsequent series of process steps P7-P10 carried out as described further below.

Figure 8 shows a perspective view of a VSS mechanism 200 of Fig. 3b arranged for making second trapezoidal protrusion feature 20 of component 100 of Fig.1 in first formed sheet 10A (Fig. 5-I) held between upper LSS unit 210 and lower LSS unit 220 by means of a SP-ISF tool T. Here, the row of LSS power pin grids 3, 4, 9 (Fig. 3a) of the lower LSS unit 220 is selected to be automatically retracted laterally within a respective slot provided about plane S-S by means of the VSS mechanism configured in accordance with the present invention by the ISF machine ECU. The retraction of this row of LSS power pin grids 3, 4, 9 facilitates in making the second feature, e.g. trapezoidal protrusion 20 raised above the separation plane S-S by pressing SP-ISF tool T upwards. Again, it is clearly visible that the initially formed sheet 10A is firmly held completely between upper LSS unit 210 and lower LSS 220 after retracting the row of LSS power pin grids LSS 3, 4, 9 to create a working space for performing the SP-ISF process by tool T. The SP-ISF process starts at P7. At the next process step P8, tool T is automatically moved up to touch the initially formed sheet 10A at position T4. Now, the SP-ISF tool T starts forming and automatically moves further outwardly and upwardly in a predefined manner to incrementally press the material of initially formed sheet 10A for forming the targeted feature, e.g. trapezoidal protrusion 20 in the next process step P9 until the tool position T5 is reached and then the tool T is stopped at this position T5 by ISF machine. In the subsequent process step P10, tool T is withdrawn from this second feature 20 formed in the sheet 10B so obtained and retracted into a resting position thereof before proceeding to the next ISF forming operation in component 100, e.g. the third feature 30 formed with a hole 32 therein, in the sheet 10B formed with the second feature 20 (Fig. 5-II). This way with the help of CAD drawings already pre-stored in the CNC machine, all targeted features (e.g. 12; 20, 22; 30; 40) of component 100 are similarly made sequentially, accurately and quickly by this SP-ISF tool T by suitably retracting the unnecessary power pin grids 1 to 9 of either lower LSS unit 210 or upper LSS unit 220 or from both of these units 210, 220 in each step one-by-one, without damaging the feature/s formed the preceding ISF forming step/s thereof.

Figure 9 shows the second feature 20 obtained in the final process step P9 and tool T is in its final position T5 on sheet 10B (Fig. 5-II) before being withdrawn from the second feature 20 formed therein and ready to be moved away to a resting position thereof, before proceeding to the next ISF forming operation in component 100, e.g. to form the third trapezoidal feature 30 with a hole 32 formed therein.

Figure 10 shows another sequential process chart as well as the respective positions T41, T42 T43, T44 of the DP-ISF tools Tu and Tb used for performing the improved Double-Point/Probe (DP-ISF) process 2P developed in accordance with the present invention, to obtain the same first feature 12 to be formed in original sheet blank 10 shown in Fig. 1. For example, feature 12 includes a step with a first conical profile 12a and a second conical profile feature 12b with a closed cup formed therein. Original sheet blank 10 is firmly held between upper LSS unit 210 and lower LSS 220 unit and only LSS power pin grids 2 of both upper and lower LSS units 210, 220 are retracted therefrom to create a working space for facilitating the performance of the improved incremental sheet forming process 2P in the original sheet blank 10 by using tools Tu and Tb therefor. This DP-ISF process 2P starts at process step 2P1 and proceeds to a next process step 2P2 in which the upper tool Tu is automatically moved down to touch the original sheet blank 10 from above at position T41 and at the same time, the lower tool Tb is automatically moved up to touch original sheet blank 10 from below at position T42. This way, the sheet blank 10 is firmly held together between the tips of tools Tu and Tb. However, these tools Tu and Tb are aligned slightly offset for facilitating the flow of sheet material when these tools are moved in a coordinated manner radially inwards and downwards at the next process step 2P3 during the first pass of this DP-ISF forming process 2P to incrementally form the planar surface of the first conical profile 12a on these tools Tu and Tb on reaching their respective inwardly and downwardly positions T43 and T44. This way initially formed sheet 10A is obtained with the step with a first conical profile 12a formed therein. Subsequently, this DP-ISF process 2P proceeds to the second pass in next process step 2P4 to form a second profile feature 12b with a closed cup shaped formed therein. For this purpose, tools Tu and Tb are automatically moved from their respective positions T43 and T44 further inwardly and then started to move downwardly by a predefined distance and then started to moved further inwardly and downwardly to reach their respective final positions T45 and T46 in a predefined manner to incrementally press down the material of the planar surface of the first conical profile 12a to obtain the second step 12b formed with the closed cup to finally make the sheet 10B formed with targeted first feature 12. Now, both tools Tu and Tb are stopped at these positions T43 and T44 at step 2P5. As stated before, since CAD drawings are already stored in the ECU of the ISF machine, e.g. CNC machine, each and every feature (e.g. 12; 20; 30, 32; 40) of component 100 can be accurately and quickly replicated sequentially, but without causing any damage to the feature/s formed in the preceding step/s of the improved DP-ISF process 2P, while conducting the successive process step/s.

Figure 11 shows a perspective view of the arrangement of making the first feature 12 obtained in final process step 2P5 of the above-described DP-ISF process 2P, with tools Tu and Tb positioned on the initially sheet 10A completely formed with the first feature 12 before being withdrawn therefrom and ready to be moved away to a resting position before proceeding to the next series of process steps for forming the second feature, e.g. first trapezoidal feature 20 in component 100. In the same manner as described above, other features 30, 32; 40 etc. can be made in sheet component 100 in the required number of process steps either by using a SP-ISF process P or by using a DP-ISF process 2P illustrated in the figures as described above.

This ISF machine is suitably configured to form various required feature/s and/or profile/s accurately, quickly and repetitively by pre-storing the desired characteristics, profile/s and/or dimensions in the ECU thereof.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The Variable Surface Sheet-blank holder mechanism for performing incremental sheet forming process or simply ISF (SP-ISF or DP-ISF) by using the corresponding SP-ISF tool T or DP-ISF tools Tu and Tb illustrated in figures and as described above and configured in accordance with the present invention offers the following advantages:

• Applicable on conventional SP-ISF and/or DP-ISF machines by retrofitting with these improved SP-ISF and/or DP-ISF tool/s.

• Offers to make multiple pre-configured feature/s and/or profile/s in a single setting the machine ECU using the improved ISF SP-ISF and/or DP-ISF process.

• Quick and repeatable with precision to make a variety of feature/s and/or profile/s in sheet materials.

• Suitable for sheets of any materials, like metal sheets, polymer sheets, composites of pre-defined characteristics and mechanical properties.

• Save the prototype tooling cost and substantially reduces the time for the development of proto stamping parts.

The description of the exemplary embodiments above is intended to be read in conjunction with the accompanying drawings, which are to be considered part of the entire written description. In the description, relative terms such as “lower”, “upper”, “horizontal”, “vertical”, “above”, “below”, “up”, “down”, “top”, and “bottom” as well as derivatives thereof (e.g. “horizontally”, “inwardly”, “outwardly”; “downwardly”, “upwardly”, “inclined” etc.) should be construed to refer to the orientation as described or as shown in the figures of drawings under discussion. These relative terms are for convenience of description and do not require that the corresponding apparatus or device be constructed or operated in a particular orientation.

The terms concerning attachments, coupling and the like, such as “connected” and “interconnected”, refer to a relationship, wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise.
The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments.

It is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation. The exemplary embodiments described in this specification are intended merely to provide an understanding of various manners in which this embodiment may be used and to further enable the skilled person in the relevant art to practice this invention.

Although, the embodiments presented in this disclosure have been described in terms of its preferred embodiments, the skilled person in the art would readily recognize that these embodiments can be applied with modifications possible within the spirit and scope of the present invention as described in this specification.

Accordingly, the skilled person can make/devise innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies and assemblies, in terms of their size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.

The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to imply including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention.