Week 9 - Project - Master Section Development

CREATION OF CLASS A, B & C SURFACES, DOGHOUSE ,4-WAY LOCATORS AND DRAFT ANALYSIS FOR B-PILLAR

Objective:

The main objective of this project is to create class A, B & C surfaces, doghouse, 4-way locators and the draft analysis for the B-pillar using Catia V5.

Introduction:

The dog house is also a feature used in plastic product, in this component, this feature is used to avoid sink marks on the component and even it is used at the places, where there are perpendicular screw Bose directions and even at the more heights to the mating component. For the purpose of increasing heights for locators in this model the dog house is used.

Methodology/approach:

• For the creation of tooling axis and draft analysis, the first important input is the class A surface, then further using Catia V5, create the tooling axis and draft analysis, first, check the best direction (X, Y, Z) and select the direction at which the part will easy to remove from the mold. Y direction is selected for the Tooling axis.

• For creating the tooling axis use the Y direction, use the bisecting method for creating the tooling axis, first draw a intersection curve in ZY plane and then use the vertical line and draw a bisecting lines for both of them to get a centre axis line so we can have the centre for the tooling axis. Using the master section, the extract can be taken for intersection.

• Then perform the same in the other XY plane and get the bisecting lines for the tooling axis. Then use both the tooling axis in XY and ZY plane and get the bisecting line for them to produce the main tooling axis.

• Publishing – Use the publish option to publish the Class A surface and the tooling axis, so it is easy for using it for other features.

• Before working on the class B- surface, to make sure class A is up to the mark with the master section, there are some improvements made in the class A-surface as add-on with the flanges.

• Thicken the B-Pillar using some of the surface features, since the edge fillet has to be at equal distance on the offset surface, we add the thickness to the edge fillet, the final offset will be the B surface.

• The C surface is the surface which give the thickened body surface. This is made using the sweep surface option with the reference as outer surfaces of class A improved surface. Then it is trimmed with the Class A-surface.

• Then join and trim them to obtain the thickened part surface.

• Using part design create a solid body from the closed body feature.

• Draft analysis for the thickened B-pillar, the minimum draft angle is 3 degree for the B-pillar, there are some sections in the class A surface with less than minimum draft angle, those surfaces have to be improved.
• Analysis on class A surface

• Draft analysis for class B and C surfaces

• Analysis on running point - with the help of this option, the angles at every point can be checked easily. The area with green color can be suitable for the present tooling axis.

For the class B-surface there are some sections, which is less than the minimum draft angle that is because of the class A-surface, if the class A-surface is improved the B-surface will also be improved.

• Now let’s go for the design of the dog house with 4-way locators

There are some of the design dimensions for the creation, they are:

For the dog house:

• "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).
• Height of (B) should be between 3.0 – 6.0 mm

So, the designed dog house and locators are shown below using these dimensions. The doghouse and the locators are created using the references from the, master sections, but since the master sections has some dissimilarities in its design the improvement is necessary, the improved design is used in this case

The draft analysis is performed on the dog house with the locators with main tooling axis and lifter tooling axis. Draft angle here is 0.5 degree. Here the lifter tooling axis is considered for the dog house inner faces.

Below with the lifter tooling axis. 0.5-degree draft considered for the inner side walls.

Now let’s move on to the Rib design & analysis for this component:

Some of the important design aspects are:

For the B-pillar design the Thickness(t) is 2 mm

So Here are some calculations for the Coin holder ribs:

• Rib thickness at tip = should not be less than 75 mm
• Rib draft angle = Should not be less than 5 degree
• Edge fillet = Should not be less than 2 mm
• Rib depth or height = Should be greater than 5t, for this design 5*2.5=10 mm
• Rib root thickness = This should be 30% less or more than the thickness(t).
• The spacing between ribs = 50 mm

Let us now see the design:

• Then, use the feature draft analysis to check the draft analysis of the B-pillar ribs using the tooling axis.
• Use the analysis>Feature draft analysis toolbar to check the draft analysis, Use the compass and place in the main tooling axis direction line being upwards and lock it.
• Select the axis and the part so that the color changes according keeping the reference as tooling axis.

The ribs can be seen having a draft angle of 0.5 degree, so by this the draft analysis is good for the ribs designed.

The draft analysis is obtained for the closed surface of B-pillar with ribs.

Different views of the B-pillar with Ribs, dog house and 4-way locators:

• Front view

• Left side view

• Isometric view

• Top view

Conclusion:

The creation of class A, B & C surfaces, doghouse, 4-way locators and the draft analysis for the B-pillar using Catia V5 is carried out.