Week 11 - Project - A pillar Design with Master Section

AIM

         To create A Pillar’s Plastic Component through a given Class A Surface and Using given Master section to create B Side features, considering design rules and perform Draft Analysis on the final plastic component.

OBJECTIVE

• To make sure that the model meets the requirements of the draft angle.
• To create the Tooling axis using bisecting method / suitable axis.
• To perform Draft analysis on the given Class A Surface.
• To create the required Class B and Class C surfaces.
• To obtain a solid body from the surface using Close Surface feature.
• To create the B side features through given master section, considering design rules.
• To perform draft analysis on final plastic component.

MASTER SECTION

• Master section development takes place during the feasibility check and concept validation stages of the product life cycle.
• These are typically the guides for design requirements and which decide the component packaging after the development of the concept design, i.e., class A surfaces. 
• The master section helps us to decide the feasibility of the concept design, the clearances, the packaging, and the fixation strategy of a component before converting the concept design into a solid 3D engineering design.
• During the period of vehicle concept design, the evaluation of the master section performance depends mainly on the reference vehicle data and the experience of the structural design engineer.

A-PILLAR

• A-Pillar is located on either side of your car’s front window (or windshield).
• They also hold the hinges of your front doors. A-pillars are normally made of steel alloys.
• Besides being a supporting member, A-pillars are very crucial as far as safety is concerned. A-pillars usually carry a significant amount of load during a frontal collision or a rollover crash. So, the larger the width or cross-section, the greater would be the strength but A-pillars always block the driver’s vision (create blind spots) to some extent that can be realized while driving. So, having that said, using thicker A-pillars can make the situation even worst. It might further lower the driver’s vision and raise a question about the vehicles and passenger’s safety.
• Hence, the design of A-pillars must be optimized giving equal importance to both strength and the driver’s vision.

CLASS A SURFACE

• Class ‘A’ surfaces are primarily used in the automotive environment and refer to those surfaces which are visible in a product. In other words: A - class surfaces are those aesthetic/free-form surfaces, which are visible to us (interior/exterior), and have an optimal aesthetic shape and high surface quality.
• The surfaces or regions which are visible nowadays are considered for Class-A modelling. It is one of the reasons why the importance of Class-A modelling is increasing day by day. Majority of the time this term is used in Plastic Part designs. 

CLASS B SURFACE

• The Class B surface is created from the Class A surface, keeping the thickness of the component in check.
• The Class B surface resembles an offsetted surface from the Class A.

CLASS C SURFACE

• The Class C surface is used to bind the Class A and Class B surface together in order to form a closed surface.

PROCEDURE

Creating Tool Axis

• Initially the given Class-A surface was imported and checked for any discrepancies in the boundary and performed draft analysis on it at 3-degree draft.
• The ejection from the mould after manufacturing the interior trim must have the nominal 3-degree draft angle.
• Using master section provided, creating sketch, extracting lines and bisecting them to get Main tooling axis.

Creating Class B surface

• First offsetting entire class A surface to 2.5mm in the inward direction as 2.5mm is thickness of component.
• Some of errors were created in the offsetted surface like incomplete surfaces, gaps, small patches.

• These errors were solved by extracting surfaces, join by sub-elements to remove, extrapolating, sweep, multi-section surfaces etc commands.

• Joining patched surface to main surface, Class B surface was created.

Creating Class C surface

• We first extract the edges from the Class A surface with the help of the multi extract command which we create the path for a sweep for class C.
• Create a sweep with reference to the curve and the reference surface with a 90-degree angle and with draft direction where ever required and give the inside direction Check for the continuity of the surfaces if there is any gap go for extrapolated and trim all together now, we will get the class C surface.

• Joining class-A surface and class-C surfaces together.

Creating Solid Body

• Later, Joined Class A & Class C surface is trimmed with Class B surface to form the A pillar surface.

• Using the surface created, the solid plastic component was obtained using the Close surface feature present in the part workbench.

• The Tooling axis, side core axis, Class A, B and C surfaces were published.

DOG HOUSE DESIGN IN REFERENCE WITH MASTER SECTION

      Dog house is an engineering feature used in the plastic trim design. Dog houses are used as supporting features. Sometimes other engineering features like snaps; locators, etc. are mounded on them to increase their Height. Dog house and other engineering Features are built on B-surface.

Design rules for Dog house creation:

• "C" is where the doghouse contacts the backside of the surface
• Doghouse wall thickness at the intersection of the part wall (C) should be 40% or less than the main wall stock (T).
• The height of (B) should be between 3.0 – 6.0 mm

   

Creating Side Core Axis

DRAFT ANALYSIS

• First, we should change model into material mode.
• Go to insert and in analysis select feature draft analysis.
• Align the compass along tooling axis and lock it.
• Next click on the surface and see that the surface is within the permissible limit of the values.
• The green colour area shows that it satisfies the 3-degree draft angle. If not satisfied then by using the Running point tool the area is measured and then altered to get a successful draft for the created tooling direction.

On given Class A surface

On obtained PART BODY

CONCLUSION

• The creation of Tooling axis, Side core axis and Draft analysis were performed.
• The solid component was created from the surface geometry as per master section provided.
• The necessary screenshots and files were attached.
• The Class A, B, & C surfaces and also the Tooling Direction have been Published.