Week 9 - Attachment Feature Creation (Ribs & Screw Boss) - Challenge 1

Attachment Feature Creation (Ribs & Screw Boss)

AIM:

• To Create the Door Handle Component from the given Class-A surface.
• To Create the tooling axis for the given Class-A Surface meeting the requirements of the draft angle.
• To Attach B side Features in the component.
• To perform the Draft analysis on the model.

TOOLS USED:

• Boundary
• Join
• Multiple extract
• Bisecting line
• Trim
• Surface offset
• Draft analysis
• Intersect
• Surface sweep
• Close body surface

DESCRIPTION:

1. CREATING TOOLING AXIS -

The Tooling Direction is basically the direction that the mold pulls a part. The mold is built in two separate pieces, basically. You have a Cavity side and you have the Core side. The Core pulls apart from the Cavity and that's the Dye line or the Tooling Direction.

• Open the given CAT part file.
• Check for gaps between surfaces for that click on join and then preview.
• If theres any gap between the surfaces join them with a maximum tolerance of 0.003 mm.
• Extract the boundary and dissemble the boundary.
• Find the correct tooling axis where the material don't interfere with the tooling axis and all the elements can be created.
• Create an axis system using at the centre of the switch Bezel.
• Intersect the yz plane with respect to the class A surface.
• Hide the class A surface and create point to point lines on the suspected drafts.
• Create bisecting line with the two lines and point to create a tooling axis.
• BISECTING LINES were used to get the exact medium from the two sides so that maximum positive draft angle can be achieved.
• The tooling axis is created for the component by bisecting two axis from x and y planes.

2. PUBLICATION

• Publication is done to the component to make it visible and navigate easily.
• To publish the component go to tools > publications and then select the tooling axis and the class A surface.
• A separate tree structure is formed under the main part.

3. DRAFT ANALYSIS

The Draft Analysis command enables you to detect if the part you drafted will be easily removed. This type of analysis is performed based on color ranges identifying zones on the analyzed element where the deviation from the draft direction at any point, corresponds to specified values.

• Before going to drat analysis go to customized view parameter >under mesh >check material and then click ok.
• Now for draft analyses go to insert » analysis » feature draft analysis.
• Use the compasss to define the draft direction.
• In the colour scale change the draft angle to 3 degree.
• The component changes to green in indication of passing draft angle.
• Use running point to check the angle on the component.

• The draft analysis is complete.

4. CREATING CLASS B SURFACE

• Extract the surfaces from the class A using multiple extract and untrim them.
• Use Extrapolate to make sure that all the untrims are properly intersected to trim and offset the surfaces to 2.5 mm to create the thickness.
• Trim the extra surfaces using trim command.
• Insert them into new geometrical set and name it with respective part names.
• Apply fillets to the model after creating the entire surface.
• If the edges are outside the fillet value will be added to the thickness of the component and if the edges are inside, the fillet value will be subtracted from the thickness of the component, for instance the thickness of the component Is 2.5mm the fillet value is 15mm so the outside portion value should be 17.5mm and inner eges should be filleted 12.5mm to get uniform thickness.
• Perform trims one at a time so that it will be clear to understand.

5. CREATING CLASS C SURFACE

• Extract the boundary from the class A surface using boundary command.
• Using disassemble tool to divide the boundary as the boundary contains domains.
• Use sweep command > choose profile type line > subtype as with draft direction > choose guide curve and draft direction > draft angle as 3 degree > preview.

• After getting sweep then trim the output with class B surface to get final output.

• Now open part design workbench and using close body surface create a solid of the component.

6. B SIDE FEATURES CREATION

a.CREATING THE RIB

Ribs are thin wall protrusions that extend perpendicularly from a wall or plane. They are usually found in clusters offering support to a plane that would have otherwise been too thick, but can also be stand-alone support for a single wall. They are commonly used to provide additional support and strength to a part. Thickness and location are essential to rib design.

First, the base surface where the rib has to be created is extracted using the Extract command. A positioned sketch is created and the profile for the rib is drawn.

Next, the profile is extruded, to find the height, h=Wall thickness * 5

=2.5*5

= 12.5 mm

Therefore, the height is 12.5 mm

The extruded surface is thickened,

Thickness,w=0.4*t

=0.4 2.5

=1mm

Therefore, the thickness of the rib is 1 mm

The draft is applied to the sides of the ribs. As per the design rule, the ideal draft angle is 0.5 deg

Then fillet is applied to the faces of the rib. As per the design rule, the fillet can be 0.25 mm.

Now, we have to check for the Rib root thickness.

To check for the Rib root thickness, We have to take an Intersection with the XY plane and the Coin holder component. Once we get to the intersection we have to create a tri-tangent circle at the rib area and measure it. The value must be within 30% greater of the wall thickness.

b.CREATING THE SCREW BOSS

Screw Boss features are commonly found in injection molding designs. They are used to aid in the assembly of molded parts by providing a channel for a screw. Their primary use is to strengthen holes or slots in the surface present in the part model.

Design rules consider while creating a screw boss

• Thickness

• Draft

• optional radii

• Boss gussets

• Type of ejection

The construction process of creating the screw boss is explained below:

For thickness, the design rule is as follows,

Thickness,w=0.6*T

=0.6*2.5

=1.5 mm

Therefore, the thickness of the boss can be 1.5 mm per side.

In this case, we have considered the size of the screw boss as M06.

Once the sketch is completed, then it is padded using the Pad'command. The height to diameter ratio can be 3:1

Next, the draft is given to the boss. As per the design rule, the draft given for screw boss is 0.5 deg.

Then fillet is applied to the faces of the rib. As per the design rule, the fillet can be 0.25 mm.

7.FUTURE TREE: