Week 11 - Project - A pillar Design with Master Section

Aim: -

• Design an A-Pillar with Dog House plastic component through the given Class-A surface and Master Sections.
• Detailed explanation of Draft Analysis and Tooling Axis creation as per given Master Section.

Theory: -

• Before designing any component we have to go through its given Class-A, first we need to do some DESIGN RULES CHECKS i.e., surface quality check of the given Class-A.
• MAIN TOOLING AXIS (using Bisection Method) :- 2^nd Step is the Creation of Tooling Axis (It is the direction along which the mould moves).
• To decide the Tooling Axis for a given Class-A, we need to follow the Master Section given.
• Lifter Axis is made by creation of a plane on the given Master Section.

Creation TOOLING AXIS by BISECTION METHOD :-

• Faces of the component are identified first which may create a problem at the time moulding.
• In this method, Sketches are being made along with their Intersects to check whether the component’s faces are clearing the Tooling Axis in a particular direction.
• Sketch which we obtained after intersecting the faces with the respective planes, that are parallel or have small inclinations with the expected Tooling Axis (made for reference purpose) are only checked by creation of construction lines along them and bisecting them at last.
• Bisection method is only applied in the direction where we have a doubt that the particular face is not going to clear the tooling.
• The faces that are perpendicular or near to 90 degrees with the Tooling Axis clears the tooling easily and we don’t need to apply Bisection on their sketches.
• Bisected lines if more than one, are again bisected to get the Tooling Axis before doing Draft Analysis of the CLASS-A.
• Bisection Method is only applied to Symmetrical Surfaces only.

Draft Analysis: -       

• Draft Analysis is done to ensure that the solid component or its given Class-A skin meets the prescribed Drafting standards.
• In Automotive Industries,3 degrees draft is usually accepted as a norm amongst the Product Designers and the Mould Makers.
• Before performing the Draft Analysis, Tooling Axis is made in a manner that the component along with its Holes, if any, clears the selected tooling direction.
• Now, the 1^st step is to define the Current Draft direction by dragging and merging the compass on the top right corner of the CATIA window with our Tooling Axis and then locking the draft direction.
• Picking the surface by clicking on it shows the different drafts given on the various parts of a component with the help of colours whose values can be estimated from the Colour Scale in the Display option.
• Make sure to give a minimum of 3 degrees draft on the faces parallel to the Tooling Axis in general, and 1.5 deg & 0.5 deg on outer parallel faces and the inner parallel faces of Dog House that are parallel to the Main Tooling and Lifter Tooling Axis.
• We can manually check draft on all the faces by choosing the ‘Analyses under the running point’ in the Display option of the Draft Analysis Toolbox and then we can move on to the creation Class-B surface creation.

Draft Analysis on the A-Pillar along with its B side/Engineering feature (Dog House):-

Analysing Class-A: -

• Upon performing the draft analysis on the component, we saw that most of the surfaces are above the specified 3 deg draft.
• Images of Draft Analysis: -

Class b surface: -

By offsetting class a surface by 2.5 mm we created class b surface

Closed body: - by using joined class A & class c surface we trimmed the class b surface and we got a closed body.

 

Analysing A-Pillar along with Dog House :-

• Upon performing Draft Analysis, on the A-Pillar CAD and Dog House outer and inner faces with supporting Ribs we confirmed that the component having angle above 3 degrees,1.5 deg and 0.5 deg except few faces on the A-Pillar alone as shown below in the ppt.
• Here, we’ve improvised the draft angle to 2.9 deg (for A-Pillar),1.48 (for Dog House outer faces) and 0.48 deg (for Ribs and inner face) for the Main Tooling and Lifter Axis in order to include minor deviations.
• Images of Draft Analysis: -