Disc cam profile design based on 3D Studio MAX
Cams are widely used in industry. For a variety of different machines, the cam working profile can be designed analytically or graphically. When designing with analytic methods, it must be programmed specifically for a particular form, which is time consuming and has little chance of being reused. The graphic method is simple and easy to perform, and the general mechanical graphic design has been able to meet the requirements of use.
First, the disc cam contour design
The following is an example of a cusp-to-center linear motion follower disc cam to introduce the whole process of cam contour design.
It is known that the cam rotates clockwise at an equal angular velocity ω, the radius of the base circle is rb=30 min, and the movement law of the follower is as shown in Table 1.
Table 1 Movement law of follower
1. Create base circle and follower
In the newly created .max file, use the ciecle command to create a circle with a radius of 30mm as the base circle, and use the box command to create a cuboid as the follower. For the convenience of drawing, then use the box command to create the auxiliary lever and the auxiliary lever. The center coordinates of the piece are moved from their geometric center position to the center of the base circle; they are aligned using the Align command and their initial relative positions are finally determined as shown in Figure 1.
figure 1
2. Draw a displacement line diagram
In the Track View, the movement trajectory of the follower along its Z direction is edited into a displacement line diagram as shown in FIG. 2 according to the movement law of the follower. The editing process first needs to set several key points, then edit the animation values ​​of each key point and the type of tangent at the key points according to the requirements of the motion law of the follower, and fit the points into the required motion curve. When the time slider is moved, the follower reciprocates up and down according to the required motion law.
figure 2
3. Determine the end position of the follower during the reversal process
image 3
Move the time slider to a point (such as frame 30), as shown in Figure 3, the follower will rise a distance. Use the “Select and Uniform Scale†command and simultaneously press the “shift†button to extend the auxiliary lever in the Y-axis direction to the end of the follower and copy. Then, use the "Rotate" command to rotate the copied auxiliary lever 30' in the opposite direction, as shown in Figure 4. Several positions of the end of the follower are determined in the same way, as shown in FIG.
Figure 4
Figure 5
4. Draw cam working profile
Turn on the capture. Use the "NURBS Curve/Point Curve" command to sequentially capture the end position of the auxiliary member and draw a smooth curve, that is, a cam profile. As shown in Figure 6.
Image 6
Extend the curve with the "Extrude" command to obtain a disc cam. As shown in Figure 7.
Figure 7
Second, the dynamic simulation of cam mechanism
The cam mechanism motion model is established, and the rotation and reciprocating movement of the cam and the follower can be set to be animated according to the respective motion laws, and the two members are in the correct relative position in the initial state. Thus, when the animation is turned on, what is displayed on the screen is that the rotation of the cam causes the follower to reciprocate.
As can be seen from the above, the follower has been reciprocating up and down within a range of 360o according to the required motion law. What you have to do now is to let the cam turn. Place all components in the initial correct relative position and link the cam to the base circle with the "Select and Link" command, then in the "Track View", edit the rotation curve of the base circle around the Z axis to make it in the 360o range Do it at a constant speed. In this way, the cam rotates at a constant speed with the base circle.
Another way to turn the cam is to move the geometric center of the cam to the center of the base circle, and in the "Track View", edit the rotation curve of the cam around the Z axis to make it rotate at a constant speed within 360o. In this way, the cam rotates at a constant speed.
Third, summary
The disc cam profile design based on 3D Studio MAX has the following advantages:
1. Avoid the tedious programming process using analytical calculation methods;
2. Avoiding the graphic method using the scale drawing and measuring the line segment drawing, which improves the efficiency and improves the accuracy;
3. Based on the cam contour design, the establishment of the mechanism motion model is simple and effective.
4. The created graphic file can be imported into other software for editing, so as to facilitate the design and processing of the cam.
Steel H Beam,H Section Steel,H Beam 200,Metal H Beam
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