FIELD OF INVENTION

[001] This invention relates to the field of CNC profile cutting by milling/ routing process and preventing vibration during this process. The present application is based on, and claims priority from an Indian Application Number 201741021665 filed on 21st June 2017, the disclosure of which is hereby incorporated by reference herein.

BACKGROUND OF INVENTION

[002] In CNC profile cutting machines, it is possible to clamp the sheets only at the edges.

[003] This results in vibration when cutting middle of sheet.

[004] This results in damage to work-piece and cutting tool.

[005] Some clamps use a spring-loaded plunger, that travels with the tool. Such plunger clamps typically drag on the sheet, thus scratching or damaging the surface.

[006] Hence there is a need to develop an automatic clamping system that can clamp the middle of sheet, without sliding on the sheet.

OBJECT OF INVENTION

[007] The principal object of this invention is to develop a robotic clamping system, that can clamp sheets in middle.

[008] Another objective of the invention is to develop a clamp that will hold without sliding or scratching the surface.

[009] Another objective is to develop intelligent software method to identify and calculate the clamping & un-clamping points automatically. [0010] These and other objects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF FIGURES

[0011] This invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:

[0012] FIG. 1 depicts the proposed robotic clamping system mounted on a CNC machine

[0013] FIG. 2 depicts close up view of the proposed robotic clamping system mounted on a CNC machine

[0014] FIG 3. Shows the side of the CNC machine Z-axis which is inturn mounted on the X-axis.

DETAILED DESCRIPTION OF INVENTION

[0015] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. For example, it should be noted that while some embodiments are explained with respect to cutting of sheet material in CNC milling machine, any other application may also incorporate the subject matter of the invention with little or no modifications. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

[0016] The embodiments herein describe an intelligent dynamic robotic clamping system, that will clamp in the middle of the sheet without sliding on the sheet surface, thus minimizing damage to sheet and tool. Referring now to the drawings, and more particularly to FIGS. 1 through 2, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.

[0017] FIG 1 shows a CNC cutting system 100, consisting of Y-axis 103, X-axis

104, Z-axis 105, Spindle motor 107, Spindle clamp 106 etc.

[0018] FIG 1 shows raw material sheet 101 clamped to ground table by set of fixed clamps 102. [0019] The proposed robotic clamp 100a is mounted on the X-axis (preferable) or Z-axis of the machine.

[0020] It consists of Arml 108, Arm2 109 and end effector 110.

[0021] The end effector 110 is typically a solenoid with a rubber foot. When solenoid comes down, it will rigidly hold the sheet. It can also be any other actuator giving smoother motion like RC servo, servo motor etc. The rubber foot will typically have multiple foots, to offer multi-point stable grip on the sheet.

[0022] FIG 2 shows the proposed robotic clamping system in more detail.

[0023] It is a 4 degree of freedom robotic clamp (three actuated joints and one free joint). Rotary axisl (111), Rotary axis 2 (112), Rotary axis 3 (113) and vertical linear axis 114.

[0024] Axis 111 and 112 are controlled by motors 120 and 121 respectively, which are in-turn controlled by an intelligent controller 100b.

[0025] Axis 113 is a free rotary joint without actuator.

[0026] Axis 114 is a vertical linear axis, with actuator 110.

[0027] The motors 120 and 121 have encoders mounted on them for accurate position detection.

[0028] Once clamping location is finalized, the motors 120 and 121 move the end effector to the desired clamping location.

[0029] The vertical axis actuator is energized and clamp goes down and clamps the sheet. [0030] Once clamping is engaged, the motor 120 and 121 are de-energized, allowing the joints to move freely, thus allowing the base point of the robot arml at pivot 111 to move freely along with XY moves of the machine.

[0031] Even though motors are de-energized, the encoders on the motors keep feeding position info to a controller.

[0032] Using this info, controller intelligently decides when to unclamp from the sheet, (using forward, inverse kinematics maths)

[0033] For unclamping, first the vertical axis 114 moves up releasing the clamping force. Immediately upon this, the motors 120 and 121 are re-energized and can carry the end effector to the next clamping location.

[0034] In one embodiment, multiple such 4axis robotic clamps are used, such that one clamp is always holding the sheet near the cutting point.

[0035] In another embodiment, the 4-axis robot can be an R-theeta robot, with a linear axis 112, instead of rotary axis 112.

[0036] In another embodiment, the robot clamping system can be located on the periphery of the machine, instead of being mounted on the moving axis of the CNC.

[0037] FIG3 shows side view of X & Z-axis of a typical CNC router machine. The base of the robot 111 can be located on the X-axis, close to the bottom-most point 301 of the X-axis (i.e. On back plate 302 or bottom plate 303 of Z-axis)

[0038] 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 understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.