| ||Fasteners are a common joining mechanism in plastic parts. To place and hold fasteners in place, model matched features on both parts. Model a boss for the head of the fastener and a post to receive the threaded portion of the fastener.|
|With the Boss feature, you can design both components of a fastener placement, called head and thread. You can also design fastening ribs. Ribs are useful when the length of the boss is greater than three times the diameter.|
A Boss feature is placed at a point centered on the mating face of the head and the thread. The Boss is then extended to the next face of the target part body. To design the two mating components in the two opposite bodies, use the same placement elements with opposite directions.
| ||You can select the following placement elements:|
This feature can exist only if it can extend to a face of the target part body that is opposite to the placement point in the boss direction. The feature automatically determines the closest face of the part body to which it can extend. You can also select a different target body and flip the direction.
Use manipulators to set the dimensions of the Boss feature. When precise dimension input is not required, the manipulators are available on the preview to define the geometric parameters interactively.
During preview, the cross section of the Boss is shown in a plane normal to the camera axis. Pause the cursor over the cross section to highlight the segments that you can drag. Pause the cursor on key points to displays additional dots that you can drag. Some dots remain hidden to prevent excessive clutter in the preview.
There are two types of manipulators:
| ||When adding stiffening ribs on a From Sketch placement, the first rib alignment angle is measured from the sketch X axis.|
|For an On Point placement type, you can select a direction for the first rib alignment. Select a linear geometric element that projects onto the plane normal to the Boss direction.|
|You can select the number of ribs and the angle to fill around the Boss, beginning at the first rib alignment.|
For stiffening ribs, use the manipulators to determine the dimensions interactively.
The Boss feature includes an option for defining constant radius fillets at three different locations, as shown in the following images:
The goal is to create a couple of thread bosses using one point from a sketch and one 3D work point. For example, the part has different boss heights.
Creates a Boss feature using points of 2D sketches or 3D work points and direction elements.
| ||Head type. It is where the head of the fastener stays.|
| ||Thread type. It is where the thread of the fastener engages.|
Click the name of the dialog box tab to display definitions of the options.
Common to both types. It holds the controls for the Boss placement.
|, and click the Shape tab.|
|Body selector, to select the target body. |
From Sketch placement requires 2D points on the same sketch.
| ||Centers selector, to select the points.|
| ||Flip, flips the direction. The direction is automatically set as the one to the closest distance with the part bodies along the sketch plane normal axis. You can also flip the direction by dragging the direction preview arrow.|
|Offset From Sketch enter a value to start the boss above the sketch plane. Use a negative value to start below the sketch.|
|On Point placement requires 3D work points or sketch points and one direction.|
| ||Centers selector, to select the points. |
Direction selector defines the boss direction.
| ||Flip flips the boss to the opposite direction.|
| ||Fillet defines the constant fillet radius at the intersection between the boss (and ribs) with the target part body.|
|, and click the Head tab.|
| ||Countersink angle|
| ||Wall thickness|
| ||Shank height|
| ||Clamp height|
| ||Head diameter|
| ||Shank diameter|
| ||Clamp diameter|
Specifies the thread boss parameters of the Boss feature.
|, and click the Thread tab.|
| ||Thread boss diameter|
| ||Thread boss hole diameter|
| ||Thread boss inner draft angle|
| ||Thread boss outer draft angle|
The thread boss offers three hole types (hole check mark on):
| ||Depth Enter the hole depth.|
| ||Full Depth The hole is automatically extended to the internal wall face. The best practice is to avoid sink marks in molded plastic parts.|
| ||Through The hole cuts the entire part.|
| ||If the hole check mark is off, the thread boss can model an ejector pin.|
Stiffening ribs are optional. If the Stiffening Ribs check mark is on, all controls to input the Ribs parameters become active.
|Number of stiffening ribs indicates the number of ribs surrounding each Boss.|
| ||Rib thickness|
| ||Rib draft|
| ||Shoulder length|
| ||Shoulder top offset|
| ||Shoulder radius|
| ||Shoulder flare angle|
|Rib Fillet options|
| ||Rib fillet radius on the edges of the rib.|
| ||Rib blend radius at the intersection between the ribs and the boss.|
| ||Start angle is the first rib inclination angle with respect to the sketch X axis (when Placement is On Sketch). When Placement is On Point, the rib start angle is determined by a projected line on a plane that is normal to the Boss direction. |
Space angle is the angle to fill. This value is divided by the number of stiffening ribs to determine the angle between ribs.
| ||Start Direction the selector is active when the Placement is On Point. Use this selector to define the reference direction of the first rib.|
| ||Flip is active when the Placement is On Point. Use to reverse the direction of the first rib reference axis.|