Week 8 - Challenge 4 - Bumper

Aim

Create the Bumper Plastic component through the given Class-A surface. To begin with, the tooling axis for the given Class-A Surface should be created meeting the requirements of the draft angle and at the end perform the Draft analysis on the model.

Take the Thickness of the component to be 3 mm

INTRODUCTION:

CLASS-A SURFACE: A surface made by the designer which is given as an input to the plastic modeler/ sheet metal designer to work on. It is aesthetic surface and the outer most surface.

CLASS-B SURFACE: A surface below a certain thickness from the class-A surface is class-B surface. This is the surface that contains engineering aspects of a model for example Ribs cutout.

CLASS-C SURFACE: A surface that joins class-A and class-B surfaces together is called as a class-C surface.

Report

• A detailed report should be done explaining the draft analysis and the tooling axis creation.
• An explanation should be given on the way of creating the tooling axis, particularly the Bisecting method.

Draft Analysis:- Draft is a taper applied to the faces of the part that prevent them from being parallel to the motion of the mold opening. This keeps the part from being damaged due to the scraping as the part is ejected out of the mold, to do that the analysis is done and known as Draft Analysis

Tooling axis: The direction in which the mold or core and cavity opens is called as the tooling axis.

Tooling axis creation

As we see in 3D the tooling direction should be in the same direction of x axis, we can conclude by seeing that the tooling axis should be in this direction but for surity we need to do a visual inspection from every direction

Visual inspection

As we are seeing the class A surface in Y direction but not able to see all the faces

As seeing the class A from z direction but not able to see all the faces

But seeing it from x direction we are able to see all faces thats means the tooling axis will be in x direction

Bisecting Method

The one section surface of the class A was extracted and a point at the centre is created and an axis system was inserted to the point with the current feature is disabled.

Then, using project intersection along yz plane is created and the two inclined lines were drawn.

Then bisecting lines with the two inclined lines were drawn.

Class A Surface Draft Analysis

Then the draft analysis is performed and during the analysis we found that some of the areas are not clearing the 3 degree draft which means the tooling axis is not proper which means we need to readjust the tooling axis in order to get the accuracy

Then to get an accurate axis we use a new method in which the compass is needed and with adjusting the compass we can see slowly the red portion will turned to green which means at that point the draft analysis will be successful and then we right click and lock the compass direction and lock the direction lock.

So we again extract a surface and create a point on the surface (on surface command) and then select the line command and go for point and direction choose the poin and for direction right click and select the compass direcction and this line will be our tooling direction.

In order to check the correctness off the tooling axis choose tooling axis and select normal to view you didnt able to see the tooling axis by this check we can be sure that the tooling axis is correct

Creation of Class B:

• Now for Class B creation, we need to offset the class A surface inside by 3 mm and this is going to be our B surface
• Then we use the boundary command to check whether this is a gap or missing surface (mostly fillet created this problem)
• Then we need to make the missing surface either use the blend command, multi section solid or the last option is extract the both surface extrapolate it and then trim them and then join them
• At some places there will be gap so you have to extract these 2 surfaces and extrapolate these surface and trim them

Then use join command to remove the surfaces from the existing body by using sub element to remove which will break the link and not throw error later joining the trimmed surface and this surface

After patching and fixing the gap the outer edges are extracted and extrapolated with curvature continuity.

Creation of Class C:

The outer edges are extracted and then using the sweep (with reference surface) command the class C surface is created and at some egdes use the multisection to creat the surface which is not sweep and then join all the surfaces with the Class A surface

Final Trims:

Class A + Class C:

Then both class A and class C surface are joined to get the surface which is going to be trimmed off with class B surface in order to get the closed surface

If these 2 surface are not trimmed and giving connexity error use the entersect curve command and select both surface and check for black dot at that location both surface are not intersecting there we need to make changes and after fixing this we will trim both surface

Class A + Class B + Class C:

After trimming we get the closed surface and then we go to part design and use closed surace to create the plastic part

Draft Analysis for Solid Plastic Part

First the class – A surface is checked before creating the Class –B&C surface and finally the solid body must be analysed. Both can be done by following the below procedures.

By changing the view mode to custom view parameters – Material mode then the feature draft analysis is enabled.

Then the compass was activated and placed with the tooling axis by dragging the red pointer and then locked it.

Then, by selecting the quick analysis mode, the nominal value will be 3 degrees and checked for the component's draft angle.

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.

Draft Analysis of Class A Surface

Colour Scheme

Screenshots of the solid model with the proper color code of the draft angle in various orientations (Isometric, Front, Side, and Top View)

Isometric View

Front Side

Side View

Top View

Tree Structure

Please find the attached part file for your review