Week 9 - Project - Master Section Development

MASTER SECTION DEVELOPMENT

AIM:

The aim of this project is to develop a closed surface model by using the master section and developing B side feature for locking the degree of freedom of the component, Here we can use the B Pillar master section provided by the OEM standards.

PROCEDURE:

CREATION OF TOOLING AXIS

• A Reference point is created along the surface zero and a new axis system is created.
• The x-axis direction and y-axis direction along class A were used to create tooling direction.
• Finally, the tooling axis is created by bisecting the two lines which provide the master section, and it is published. Class A surface as input using surface operation command class B is developed.
• The tooling axis determines the direction of class c boundary swept with draft direction and draft provide in the tooling axis direction.
• When viewing from tooling direction normal to all the parts that are drafted should be visible, so it gives a rough idea to determine product manufacturing in injection moulding.

In the B pillar model, there are Two tooling directions one on the main tooling and the other on lifter side that is used to eject the parts during injection moulding.

The lifter axis is used because the attachment feature is the boundary by close walls. Extract the side of the master section.

Extract the side of the other master section also.

Then create a bisector for these extracts.

Then the bisection of these bisectors is the actual tooling axis created.

CREATION OF CLASS B SURFACE

To create the class B surface, select the class A surface and offset the surface to 2 mm.

CREATION OF FLANGE

From the master section, it can be observed that the B pillar is having a flange but the Class A surface which was given to us as input does not have any flange.

So, to create a flange on both A and B surfaces we first need to extract the boundaries of the Class A/ B surface as shown in the figure below.

After extracting the boundaries, apply a smooth option to avoid any surface continuity issues.

The surface of Class A/ B which is attached to the boundary needs to be extracted first which will act as a reference surface for the flange while sweeping.

Now sweep the boundary with the reference surface(the surface which we extracted) and give an appropriate angle such that the flange is aligned with the master section.

Offset the sweep surface to 2mm.

Similarly, Do it on the other side of the B pillar.

Now join the sweep surface with the class A surface and the offset surface with the class B surface to get the surface attached with the flange.

CLASS C SURFACE CREATION

To create a Class C surface, first, extract the boundaries ( all edges separately) of the Class A surface ( the surface with flange).

After extracting the boundary, we need to perform a smooth ( max. Deviation as 0.001mm) operation on it to create a continuous tangent surface.

Now using the sweep option create the surface.

FINAL TRIM

To create the B pillar component, we need to join all these surfaces(i.e., Class A, B, and C surfaces.)

First, join the Class A surface with the Class C surface and then trim this joined surface with the Class B surface to get the final output.

CLOSED SURFACE

Since these surfaces are hollow, we need to close them to form a thick solid component.

Using the Closed surface option in part workbench, a solid body from the surface can be formed. This will give us a solid component.

DOG HOUSE

The dog house is an engineering feature that is used in the plastic trim design. It is used as a supporting feature for other engineering features like snaps, locators, etc. that are mounted on the doghouse to increase their strength and to avoid sink marks.

To create a doghouse, we need to follow the master section which was given to us as input. The top surface and the supporting walls of the doghouse on which the locator is laid are created by simply extracting the lines from the master section in a sketch and extruding them to a certain length.

Now the help of master section 2 extracts a line to create a closing surface to the doghouse.

Trim it with the main surface and give a thickness of 2 mm to it and draft it to an angle of 0.5 degrees.

Locators are a great way to make sure the parts we are putting together fit the way we want them to fit. To create a 4-way locator, we need to create a sketch with two lines intersecting each other perpendicularly forming a ‘+’. Once the sketch is created, pad it to form a locator.

A draft of 0.5 deg is given to the locator and a chamfer of 5mm at 45 angles is given to the top edges of the locators.

The inner walls of the doghouse are created at an offset value of 1.2mm from the outer walls and the top surface for the inner walls is created by intersecting the Class A surface with the back wall of the doghouse.

This surface is then split with the close solid to create the inner walls of the doghouse.

To draft the inner walls of the doghouse, a lifter axis is first created and then a 0.5 deg draft is given to it following the draft direction of the lifter tooling axis.

The inner walls of the doghouse are created at an offset value of 1.2mm from the outer walls and the top surface for the inner walls is created by intersecting the Class A surface with the back wall of the doghouse.

This surface is then split with the close solid to create the inner walls of the doghouse.

RIBS

Ribs are created to increase the strength of a part without increasing the thickness of its walls. Because less material is required, ribs can be a much more cost-effective solution as well.

To create a rib, we first need to draw a straight line(where we want a rib) in the sketcher workbench. After creating the line, extrude it and pad it.

Since we need to create multiple ribs which are 50 mm apart, first go to the Class A/ B surface and extract the boundary/ edge where the flange is connecting to the main body. Now using the boundaries, create repetition points that are at 50mm from each other.

Now copy the rib(solid body) that we created and paste it into the main tree structure. Using the translate option the copied rib can move from one point to another. Repeat the above step for creating all the ribs and position them on the points that we have created using the repetition points option.

Offset the Class B surface to 10mm and trim the ribs with it removing the excess portion of the ribs and giving a draft of 0.3 to the ribs.

Create the ribs on the other side also.

Once all the engineering features are created, add it/ trim it to/ with the main body i.e., B pillar, and give appropriate fillet value to all parts of the body.

DRAFT ANALYSIS ON FINAL MODEL

To give draft direction, use the compass and align it with the tooling axis which we created for the model. Once it is properly aligned, select the surface of the model which will show us the draft angle given on the component. Make sure the draft angle on the component is having a 3 deg draft value (component showing green in color).

CONCLUSION:

B Pillar component with engineering feature using the master section and Class A surface as an input has been successfully created and draft analysis has also been performed for the same.