Sahaj Panchal's Blog

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Assembly mates in SolidWorks–advanced mates

Advanced mates in SolidWorks….

List below shows the advanced mates…

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As stated earlier in previous post, the advanced mates are used to assign limited motion to components, reducing degrees of freedom further. Say you can assign limit for a part so that it’ll move within the define limits only, or you can make a part follow certain path, and likewise.

(To use the following examples appropriately you need to first assign the standard mates so that the parts will be in proper alignment as shown in the respective images.)

Symmetric – forces two entities to be symmetric with respect to a plane/planner face.

Select two planes/planner faces, lines and points in this mates. But the selection should be of a same type, means planes only, or points only. Two planner faces of links are set to be symmetric with the right plane as the reference.

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Width – places two planes such that they are at equal distance from the selection.

Width selection – two planner faces – parallel or not parallel, in between which the component is to be placed

Tab selection – two parallel/non-parallel faces or one cylindrical face

The tab will be placed at same distance from the width selections. If the component to be placed is having planner faces then you can invert the mate selections.

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Path – force a component vertex to follow a path.

Component vertex – point, 3d point mid-point

Select a path – open, closed loop

The mate places a selected vertex at a random (mostly nearest from the current) location on path. You can even sketch the path within assembly as well. (which you need to do in the following example.) Draw the approximate curve shown (2d/3d).

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Select a mid-point of a bottom edge of the camera and select the path just drawn. You can invoke selection manager to let you select open or closed loops. The point is placed on the curve. Now if you try to move this part, if you observe, one can still place it anywhere on the path and even in any orientation. The video below says this all…

Component having path mate assigned, but can still be moved in any orientation.

You can reduce degrees of freedom of the part further by placing it at a finite distance on the path, which can be either a length value in document unit or a percentile value. Edit the mate to do so, and select an option as required instead of free in the Path Constraint sub-option. Distance – length/percentile length – will be measured from the start point of the sketch/curve, which can be flipped by checking Flip dimension.

But again doing so will make the component stick to the defined point, which still can be rotated in any axis. If you want it to move freely along the path, while still maintaining the correct orientation, you can edit Pitch/Yaw Control and select Follow Path option, which prompts you to select an axis of the component which will be tangent while moving along. The vector direction can be flipped as well. In the image below, the Z-axis of the camera is selected to be tangent to the path.

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Path mate assigned to the camera, while restricting it’s pitch and yaw moment.

As you can see in the video above, the component’s Z-axis is constrained to be tangent along the path. Reducing degrees of freedom further will prevent the part rolling along it’s tangent axis. Set Up Vector in the Roll Control sub-option and select a linear/planner element to define a direction and select which axis (from the remaining two) will be oriented in the direction selected. Again it can be flipped. The pink face is selected as vector direction in this case. Note that whenever you select a plane/planner face as a direction, it’s normal is used to define the direction.

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Further reducing degrees of freedom of the part by restricting the roll movement.

Now the part maintains correct orientation while moving along the path.

Linear/Linear Coupler – applies translational relation between components.

Moving one component forces the second one into the same or different direction, and up to the same or different distance. The example below indicates this. Moving the slider in longitudinal direction forces the bucket to go up and down.

The mate forces one component move while moving another in a specified direction, at a specific ratio.
Linear/linear coupler mate in reversed direction.

To do so: First place the components as required using standard mates. Then select a line of the slider as shown and select the temporary axis of the bucket. (Hide/show items > Temporary axis). Assign distance ratio if required, and mark Reverse if required to move components in reverse direction.

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Ratio here defines translation distance that’ll be covered by the second component while moving the first one, and vice-versa.

Limit mate (Distance) – limits the translation movement within defined range.

Assignment of the mate is same as of distance mate, in addition to this, simply enter max. and min. limits. In the example below, you can assign a range to the movable jaw so that it moves within the defined limits only. Select the highlighted faces as shown, define the current position, and max. and min. limits(0-114mm). You’re done!

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Try to move the movable jaw, it’ll only move within the defined limits.

Jaw movement without limit mate.
Video shows the movements of assembly components with limit mate applied to the movable jaw.

Limit mate (Angle) – limits the angular movement within defined range.

Again, assignment is same as standard angle mate. In addition, enter min. and max. range a part can move within. In this example, select the faces of the hinge as shown, define current position and define angular limits (0-270deg).

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Hinge component in motion without limits. Notice how the components are interfering each other. This can be avoided by assigning angular limits.
Hinge movement with angular limits applied.

 

That’s all for the Advanced mates. Click here to get the models shown within the post. Visit again for next post which contains Mechanical mates.

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