CN106844992A - Multidirectional hammering type progressive forming method and product obtained by same - Google Patents

Abstract

The invention discloses a multi-directional hammering type progressive forming method and products obtained by the method. In the method, tool processing tracks are compiled into wave processing tracks, and the direction, wavelength and amplitude of the tool hammering are controlled by changing the direction, wavelength and amplitude of the wave track. Frequency and amplitude, only on a three-axis CNC milling machine and a dedicated progressive forming machine, the multi-directional hammering progressive forming with periodic contact between the tool and the sheet can be realized. The method can improve the problem of uneven deformation of the sheet metal that occurs in the ordinary incremental forming process, thereby improving the forming performance of the sheet material.

Description

A multi-directional hammering type progressive forming method and products obtained by the method

technical field

The invention relates to a multidirectional hammering type progressive forming method and a product obtained by the method, and belongs to the technical field of sheet metal progressive forming processing.

Background technique

Sheet metal incremental forming technology adopts the idea of rapid prototyping technology "layered manufacturing", driven by CAD model, can form products without mold or only punch, very suitable for processing single-piece or small-batch thin-shell products , is a favorable supplement to traditional stamping. It has broad application prospects in manufacturing industries such as aviation, aerospace, home appliances, medical equipment and automobiles.

Commonly known as incremental forming, the tool and the sheet are always in contact during the forming process, so it is also called continuous contact incremental forming. If during the forming process, the tool also performs a "hammering" action while moving along the processing track, that is, the tool is continuously lifted and dropped, and makes periodic contact with the sheet, it is called hammering progressive forming. Compared with continuous contact incremental forming, due to the periodic contact with the sheet metal, the hammer-type incremental forming has very little friction with the sheet material along the horizontal direction of movement, which further improves the forming performance of the sheet material, reduces the deformation force, and does not It will cause the parts to be twisted along the processing direction, and can also form mesh plate parts.

The prototype of sheet metal incremental forming is that the craftsman uses the method of hammering to deform the sheet material to the shape to be formed. Since the hammering direction can be freely rotated when the craftsman hammers the workpiece, the local deformation of the sheet can be controlled by continuously adjusting the hammering direction and hammering force during hammering forming, so that the local thickness of the workpiece can be controlled. In contrast, the hammering angle of the existing hammering incremental forming is fixed at 90°, and the hammering direction does not change during forming, so the plate thickness cannot be freely adjusted.

Contents of the invention

The invention proposes a new multi-directional hammering progressive forming method, which avoids the problem that it is difficult to change the hammering direction by hydraulic or mechanical driving in the current hammering progressive forming method. The hammering direction of the tool can be flexibly controlled by reasonably programming the NC program to control the local thickness of the workpiece and improve the formability of the sheet.

The technical scheme that the present invention adopts is as follows:

A multi-directional hammering type progressive forming method, comprising the following steps:

(1) Use 3D software to establish a 3D geometric model of the workpiece;

(2) Using 3D software or manual programming to generate the continuous contact incremental forming processing trajectory of the workpiece;

(3) Output the discrete points of the continuous contact incremental forming processing trajectory in step (2) to meet a certain forming accuracy;

(4) interpolating the processing track points output by step (3) to obtain new processing track points;

(5) Introduce sinusoidal fluctuations in the vertical direction according to the tool horizontal speed and processing time, adjust the new processing trajectory points obtained in step (4), control the introduced amplitude, and generate a hammering-style progressive hammering angle of 90° forming trajectory;

(6) Take the line connecting the tool trajectory points between two adjacent troughs as the rotation axis, and rotate the trajectory point between the two troughs around the rotation axis by a specific angle to realize the controllable direction of the fluctuation;

(7) Output the wave processing trajectory of multi-directional hammering progressive forming;

(8) The forming tool performs multi-directional hammering progressive forming on the workpiece to be processed according to the processing track described in step (7).

Further, the specific process of step (3) is: according to the wavelength of the sine wave to be introduced and the number of track points that each wavelength should meet, the processing track points output by step (3) are interpolated by the Lagrange linear interpolation method.

Further, the sinusoidal fluctuation is shown in formula (1).

In the formula, ( _xi , y _i , _zi ) represent the spatial coordinates of a point i of a tool processing track output in step 4; (X _i , Y _i , _Zi ) represent the space Coordinates; A represents the amplitude of the introduced sine wave; λ represents the wavelength of the introduced sine wave; v represents the horizontal feed speed of the forming tool; t _i represents the elapsed time required for the tool to go from the initial position to point i.

Further, the direction of the line connecting the tool track points described in step (6) approximates the direction of the tangent of the horizontal tool movement.

Further, the output format of the processing track in step (7) is a format recognizable by the CNC machine tool or the special incremental forming machine.

Further, the concrete process of described step (8) is as follows:

Make the workpiece to be processed into a flat structure, make the geometric center of the workpiece to be processed coincide with the geometric center of the forming fixture, and press the surrounding of the workpiece to be processed; the forming tool is controlled by a CNC machine tool or a special progressive forming machine according to the steps (7 ) generated wave trajectory data point by point progressive shaping.

A product obtained by adopting any one of the multi-directional hammering progressive forming methods.

The beneficial effects of the present invention are as follows:

It is difficult to change the direction of hammering by hydraulic or mechanical driving in the existing technology. Redesigning progressive forming equipment or adding a controllable multi-directional hammering device to existing equipment obviously requires high cost investment, long cycle and complicated control system. Feasibility cannot be determined.

The invention compiles the machining track of the forming tool into a fluctuating machining track, controls the direction, wavelength and amplitude of the wave through a numerical control program, and can flexibly realize the multi-directional hammering progressive forming in which the tool and the sheet material are in periodic contact. The multi-directional hammering progressive forming method of the present invention can overcome the problem that the plate thickness of the existing progressive forming is mainly determined by the forming angle, and can better control the local thickness of the workpiece, thereby improving the formability of the plate.

The multi-directional hammering type progressive forming method described in the present invention can realize the control of the hammering direction, frequency and amplitude only through the direction, wavelength and amplitude of the wave trajectory in the numerical control program, so there is no need to change the existing forming equipment Design, does not need to add additional devices, low cost, can be used on the existing three-axis CNC milling machine and special progressive forming machine.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are For some embodiments of the present invention, those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is a schematic diagram of the generation process of wave machining trajectory in multi-directional hammering incremental forming.

detailed description

The embodiments of the present invention are described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and describes detailed implementation and specific operation process, but the protection scope of the present invention is not limited to the following implementation example.

The multi-directional hammering progressive forming method researched by the present invention compiles the tool processing trajectory into a wave processing trajectory, and controls the direction, wavelength and amplitude of the wave through the numerical control program. When the forming tool moves according to the programmed processing trajectory, it can be Realize the multi-directional hammering progressive forming with periodic contact between tool and sheet. With this forming method, only ordinary three-axis CNC machine tools are needed to realize the change of the hammering direction, which can better simulate the craftsman's hammering forming process, and overcome the problem that the thickness of the existing progressive forming plate is mainly determined by the forming angle, so that it can Improve the formability of sheet metal and improve the forming quality of products; including the following steps:

(1) Use 3D software to establish a 3D geometric model of the workpiece;

(2) Using 3D software or manual programming to generate the continuous contact incremental forming processing trajectory of the workpiece;

(3) Output the discrete points of the continuous contact incremental forming processing trajectory in step (2) to meet a certain forming accuracy;

(4) interpolating the processing track points output by step (3) to obtain new processing track points;

(5) Introduce sinusoidal fluctuations in the vertical direction according to the tool horizontal speed and processing time, adjust the new processing trajectory points obtained in step (4), control the introduced amplitude, and generate a hammering-style progressive hammering angle of 90° forming trajectory;

(6) Take the line connecting the tool trajectory points between two adjacent troughs as the rotation axis, and rotate the trajectory point between the two troughs around the rotation axis by a specific angle to realize the controllable direction of the fluctuation;

(7) Output the wave processing trajectory of multi-directional hammering progressive forming;

(8) The forming tool performs multi-directional hammering progressive forming on the workpiece to be processed according to the processing track described in step (7).

Above-mentioned three-dimensional software can select CAD/CAM software, below is example with UGNX8.0 software, the present invention is described in detail:

Example 1

The implementation process of multi-directional hammer progressive forming is shown in Figure 1, as follows:

(1) Establish a three-dimensional CAD model of a variable-angle conical cup in UGNX8.0 software;

The generatrix of the cone cup in the three-dimensional CAD model is an arc line, the radius is 100m, the opening size of the cone cup is 100mm, and the angle ranges from 20° to 90°.

(2) The machining module in UGNX8.0 software generates the machining trajectory of continuous contact incremental forming. The precision of the incremental forming processing trajectory is set to 0.02mm, and the continuous processing trajectory is output in the form of discrete points through calculation.

(3) Enter the sine wave, and set the wavelength of each sine wave to meet the number of trajectory points to be 18, and use the Lagrange linear interpolation method to interpolate the discrete processing trajectory points output in step (2) to obtain a new processing The spatial coordinates of the track point _i are ( _xi , y, _zi ); the wavelength can be controlled.

(4) According to the formula (1), the hammering incremental forming trajectory with a hammering angle of 90° is generated. Select the sinusoidal wavelength λ to be 0.6mm, the amplitude A to be 0.8mm, and the horizontal feed speed v of the tool to be 300mm/min; the spatial coordinates of a point i on the hammering progressive forming track with a hammering angle of 90° are obtained as

X _i = x _i

Y _i =y _i

In the formula, ( _xi , y _i , _zi ) represent the spatial coordinates of a point i of a tool processing track output in step 4; (X _i , Y _i , _Zi ) represent the space Coordinates; 0.8 means the amplitude of the sine wave introduced; t _i means the elapsed time from the initial position of the tool to point i.

(5) Take the line connecting the tool track points between two adjacent troughs (approximately the tangent direction of the horizontal tool movement) as the rotation axis, and rotate the track point between the two troughs around the rotation axis by a specific angle to generate a new tool path trajectory.

In the 20°-40° area of the variable-angle cone cup opening, the hammering angle of the tool is usually set at 90°, and the tool wave direction is not changed; in the 40°-65° area of the variable-angle cone cup process, the The track point is rotated 20° around the axis of rotation; the track point is rotated 45° around the axis of rotation in the area of 65°-90° at the bottom of the variable-angle cone cup.

(7) Output the wave processing trajectory of multi-directional hammering incremental forming in a format recognizable by CNC machine tools or special incremental forming machines.

(8) Under the control of the machine tool, the forming tool is gradually formed point by point according to the wave trajectory data generated in step (7).

In the above method, the processing trajectory of the forming tool is compiled as a wave processing trajectory, and the direction, wavelength and amplitude of the wave are controlled by the program in the UGNX8.0 software, which can flexibly realize the multi-directional hammering progressive forming of periodic contact between the tool and the sheet metal . The multi-directional hammering progressive forming method of the present invention can overcome the problem that the plate thickness of the existing progressive forming is mainly determined by the forming angle, and can better control the local thickness of the workpiece, thereby improving the formability of the plate.

Example 2

A plate-shaped formed part, namely the product, is obtained by the multi-directional hammering progressive forming method described in Implementation 1. After using steps (1)-(7) to obtain the corresponding program, then use an industrial pure aluminum 1060 plate with a thickness of 1mm to cut the plate into 230×230mm, so that the geometric center of the plate coincides with the geometric center of the forming fixture , press the plate around 15mm and clamp it; the forming tool is gradually formed point by point according to the wave trajectory data generated in step (7) under the control of the machine tool; the final product is obtained.

Although the specific implementation of the present invention has been described above in conjunction with the accompanying drawings, it does not limit the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, those skilled in the art do not need to pay creative work Various modifications or variations that can be made are still within the protection scope of the present invention.

Claims (7)

1. A multi-directional hammering type progressive forming method, is characterized in that, comprises the following steps: (1) Use 3D software to establish a 3D geometric model of the workpiece; (2) Using 3D software or manual programming to generate the continuous contact incremental forming processing trajectory of the workpiece; (3) Output the discrete points of the continuous contact incremental forming processing trajectory in step (2) to meet a certain forming accuracy; (4) interpolating the processing track points output by step (3) to obtain new processing track points; (5) Introduce sinusoidal fluctuations in the vertical direction according to the tool horizontal speed and processing time, adjust the new processing trajectory points obtained in step (4), control the introduced amplitude, and generate a hammering-style progressive hammering angle of 90° forming trajectory; (6) Take the line connecting the tool trajectory points between two adjacent troughs as the rotation axis, and rotate the trajectory point between the two troughs around the rotation axis by a specific angle to realize the controllable direction of the fluctuation; (7) Output the wave processing trajectory of multi-directional hammering progressive forming; (8) The forming tool performs multi-directional hammering progressive forming on the workpiece to be processed according to the processing track described in step (7). 2. the multi-directional hammering type progressive forming method as claimed in claim 1, is characterized in that, the concrete process of step (3) is: according to the wavelength that will introduce sine wave and each wavelength should satisfy the number of locus points, The processing trajectory points output in step (2) are interpolated by Lagrange linear interpolation method. 3. The multi-directional hammering progressive forming method according to claim 1, characterized in that the sinusoidal wave is shown in formula (1). $\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\\ {\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\\ {\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; sin</span>}\frac{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; \&pi;vt</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>\end{array}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$ In the formula, ( _xi , y _i , _zi ) represent the spatial coordinates of a point i of a tool processing track output in step 4; (X _i , Y _i , _Zi ) represent the space Coordinates; A represents the amplitude of the introduced sine wave; λ represents the wavelength of the introduced sine wave; v represents the horizontal feed speed of the forming tool; t _i represents the elapsed time required for the tool to go from the initial position to point i. 4. The multi-directional hammering incremental forming method according to claim 1, characterized in that the direction of the line connecting the tool track points in step (6) is similar to the tangent direction of the horizontal movement of the tool. 5. The multi-directional hammering incremental forming method according to claim 1, characterized in that the output format of the machining track in step (7) is a format recognizable by a CNC machine tool or a special incremental forming machine. 6. The multidirectional hammering type progressive forming method as claimed in claim 1, characterized in that, the specific process of the step (8) is as follows: Make the workpiece to be processed into a flat structure, make the geometric center of the workpiece to be processed coincide with the geometric center of the forming fixture, and press the surrounding of the workpiece to be processed; the forming tool is controlled by a CNC machine tool or a special progressive forming machine according to the steps (7 ) generated wave trajectory data point by point progressive shaping. 7. A product, characterized in that it is obtained by the multi-directional hammering progressive forming method described in any one of claims 1-6.