Project - B Pillar Trim Master Section Development.

Project: B PILLAR Master Section Development

Aim: Door applique design with engineering features.

Purpose of master section: The master section helps you to decide the feasibility, clearance, packing, and fixation strategy of a component before working it in 3D.

Detailed report:

Method followed:

1. Creating a tooling axis to perform the draft analysis.
2. Creating a Class B surface from a given Class A.
3. Creating the Flanges on the Class B surface.
4. Creating a Class C surface and Plastic component by Close Surface.
5. Making a B-side features: Dog house, Four-way locators, and Ribs.
6. Performing a draft analysis from the side core (Lifter) axis and main tooling axis.
   
   

Procedure:

1. Creating a tooling axis to perform the draft analysis :

• In the given Class-A inputs we also have the Master section 1 & 2.
• From this, I extracted the lines of intersection and made a point that is created between the extracted lines to make a line that represents our main tooling axis.

Then at this point, a line or axis is created in the Y direction.

2. Creating a Class B surface from a given Class A :

• To create a Class B surface from Class A,
• First, we offset Class A for 2mm given the thickness value.

• After offsetting the surface we get patches and the surface is missing on the offset so we need to fix it first.
• For that, we are using the Multi-sections surface command by extracting the edges of the patches separately and smoothen the guide curves.

Use the Multi-sections surface to avoid any gap.

3. Creating the Flanges on the Class B surface :

• In the given Class A input, we do not get any Flanges but when we look at the Master section, there are flanges present in the intersection.
• Master sections are the guides for design requirements that decide the component packaging after technical (Styling, Concept, or Class-A) surfaces.

So, we make flanges on both sides so that we extract the boundaries of the B surface by tangent continuity

And make it smooth by curve smooth command to curvature continuity to avoid issues while sweeping.

• Then, the plane is created along the master section and the B surface intersected with these planes.
• The purpose of intersecting the surface is to have the reference of the sweep surface match with the master section lines.
• Now, the boundary is swept with a reference surface until it is parallel or aligned with the B side of the master section.

• Later, this flange is trimmed to join with the B surface and the same can be done for the other side and the A surface also.

• In the end, edge fillets are provided by measuring from the master section.

Creating a Class C surface and Plastic component by Close Surface :

For creating a Class C surface, we need to Extract all the outer boundaries and make those boundaries curve smooth of curvature continuity to avoid problems while sweeping.

Extrapolate it and Join all the extended Class C surfaces to the Class A surface and then Final trim it to the Class B surface.

After that, go to the par workbench and make a closed body by close surface feature.

5. Making a B side features :

1. Dog house

It is a ‘doghouse’ looking embossment for screws to attach one piece of plastic to another one. For example, you have a bumper cover, and you want to add a garnish to it. You would use doghouses to do so.

The dog house is created by operations given below,

• Extract the baseline of the intersection.
• Make a point and YZ plane on it.
• Create a C-section sketch and constraint it.

• Extrude the sketch and go to the part workbench and thicken it by 2mm.

• Make a line in the sketch, extrude it, and trim it to cut the dog house in the required dimension.
• Split the surface to the dog house solid
• Give a draft of 0.5 degrees and edge fillets of R1 and R3 by measuring it on the master section.

Avoid sink marks: The inner walls of the box are extracted and offset by 1.2mm to the outer side in a shape generative workbench.

Then, the base A surface intersects with the dog house's vertical back surface to get the lines that will be cut out and this profile can easily be covered with a side core or lifter axis.

This profile is extruded and later trimmed with the offset surface to get the final lower cut out. Lastly, the cutout surface is split with the thickened dog house to obtain the final dog house.

Then, the fillets and draft angle of 0.5 are provided to the dog house. But the inside surface of the dog house is drafted in the direction of the side core tooling axis.

2. Four-way locators

• To create 4 Way locators, the ribs should be created intersecting with each other.
• Open the Sketcher Workbench and Draw 2 lines intersecting each other and constraint it.

• Exit the Sketcher Workbench and Pad the Sketch with a thickness of 1.5mm.

• Now, provide a draft of 0.5 degrees to the faces. Here the pulling direction is the tooling axis and the neutral face is the top face.
• Locate the locator above the dog house and Union trim the locator with the dog house and provide the chamfer of 5*45 to the edges of the locators and fillets of 0.3mm.

• The dog house is located to the other side by creating the plane in between two dog houses and performing the symmetry operation.

Ribs:

To create the Ribs, Go to the Sketcher workbench and draw a straight line on the face you want to create a rib and constraint it.

• Extrude the line and then thicken the ribs.
• Go to the Class B or Class A Surface and select a line to extract. Select the Points repetition option to create the Points on the extracted line, give the offset distance as 50 and select the curve line.

• Now copy the Part body and paste it on the main Tree Structure. Use the Translate option to move the copied rib part body from the starting point to the ending 50mm point.
• Offset the Class-B surface to 10mm and split it to cut the rib surface.

• Now, the union trims the rib to get the final Rib structure by removing the unnecessary faces. Click Ok and Union trim the model.
• Follow the above steps repeatedly to create the ribs on both sides. The Final Solid component is created.
• In the end, provide the draft and fillets to the ribs of 0.2mm.

6. Performing a draft analysis from the side core (Lifter) axis and main tooling axis :

• To perform draft analysis, Go to the insert > Analysis > Feature draft analysis.
• Switch customize view parameters and select material.
• Click on the compass icon and align it with the tooling axis & click on the surface, we will get our results.
• From the below image we can see that the surface in green color has more than 3° and 0.4° for dog house and ribs draft which is most required for tooling feasibility. Also, see the color variant display box.

Side core tooling draft analysis :

Vertical tooling axis :

Final draft analysis :

On CLass A :

Geomtrical tree structure :

Results: B Pillar plastic component is created by considering standard design rules and make sure that the part is manufactured by injection molding.

Conclusion: There are some defects in given class A especially at corners.

Here, the draft analysis for the final component was not satisfactory as in some regions special at the corners the draft value was around 1.756 and -0.826 degrees which means the current tooling axis won't be able to extract the component properly. The solution can be to change the A-class surface around that corner or to change the tooling direction may be tilting to some angle so that it provides the positive draft angles. But changing the tooling direction means the master section also has to be changed which is again the long process.