Challenge

Week 10 - Challenge 2- Attachment Feature Creation (Dog House)

TTamil Selvan2 Jun 2023

OBJECTIVE: To create the Door Trim Plastic Component from the given Class A Surface & then create two dog houses as attachment features for it while following the given Design Guidelines.

Draft Angle: Tooling must be cleared for easy ejection of the component, from the core cavity. In order to clear tooling certain value of draft is given to the component. A minimum of 1-3deg is provided on all plastic components.

DESIGN GUIDELINES FOR DOGHOUSE IN THIS CHALLENGE:

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
The draft angle with respect to the Main Tooling Axis should be 3 degrees & the Side Core Axis should be 1.5 degrees.

First, we will begin by checking the State of Connectivity for the Class A Surface and ensure that there are no gaps between the surfaces as all the surfaces should be joined well together with each other and shouldn't consist of any discontinuities between them.

Given class-A:

There are two methods to inspect the State of Connectivity for the Class A Surface:

1. Using the 'Join' Command' from the 'Operations Toolbar':

First, we'll click on 'Join Command' and select our Class A Surface. Then, we have to ensure that the 'Check Connexity' option is marked as shown in the images below. It will check for any gaps that may be present between our surfaces. Then, we'll click on the 'Preview' button and if it doesn't show any 'Connexity Error' on our surface then it means our surface is well-connected and there are no discontinuities between it.

In our case, there are no 'Connexity Errors' for the given Class A Surface.

In case there is a 'Connexity Error', we can fix it by increasing the 'Merging-Distance' and then performing a join operation between those surfaces.

2. Using the 'Boundary' Command' from the Operations Toolbar:

In this case, we have to click on the 'Boundary' command and then select the Class-A Surface. After that, we'll click on the 'Preview' button to highlight all the boundaries that are on the Class-A surface and check if there are any internal boundaries other than the outer edge boundaries.

In our case, there is only one boundary present on the Class-A Surface which is the Outer-Edge Boundary and hence we can conclude that all the surfaces are well connected.

PROCEDURE TO CREATE THE MAIN TOOLING AXIS:

We'll view the Class A Surface from different axes to find out the optimal axis along which we can create our Tooling Axis:

DRAFT ANALYSIS FOR THE CLASS A SURFACE USING THE MAIN TOOLING AXIS FROM THE FIRST METHOD:

Now, We will perform a Draft Analysis on the Class A Surface itself using the Main Tooling Axis created using the First Method:

Before starting with a Draft Analysis Operation, we will go to the 'Customize View Parameters' option under the 'View Toolbar'. Then we will enter the 'Customize View Mode' where we will go under the 'Mesh' option and select 'Material' and press 'OK'.

To start the Draft Analysis in the 'Generative Surface Design Workbench', we will go to 'Insert' and then look for the option called 'Analysis'. Once found, we will go under that and click on 'Feature Draft Analysis. This will open the 'Draft Analysis' Dialogue box. There, we will ensure that under 'Mode' we have selected 'Quick Analysis', under 'Display' we will select 'Show or Hide the Color Scale' and then select '3 Degrees' as the permissible draft angle. Then, under 'Direction' we will choose the icon with the symbol of the compass on it which stands for 'Use the Compass to define the new current draft direction'.

PROCEDURE TO CREATE THE CLASS B SURFACE:

We'll start the procedure by creating an offset for the entire Class A Surface at a distance of 2.5mm as that is the desired thickness for our final plastic component.
As this is a complex surface hence the offset will fail to offset every element according to our necessity. It'll select some sub-elements that belong to the filleted regions by themselves that we have to remove to get the rest of the surface that is offset.

This warning will be shown when we'll try to offset the Class A Surface.

PROCEDURE TO CREATE THE CLASS C SURFACE:

We'll create the Class C Surface with respect to the Class A Surface and provide draft angles to those surfaces that are parallel to the Main Tooling Axis. Surfaces at the bottom won't be needing any draft angle as they'll get cleared by the core itself. To create the Class C Surface we have to use various commands such as Sweep with Reference Surface and With Draft-Direction depending upon the necessity and at places where it'll be difficult for us to create a surface using Sweep, we'll use Multi-Sections Surface to create those surfaces. The draft angle will be 3 degrees.

Using Sweep Command with Draft Direction to create the C Surface:

Final Class C Surface:

PROCEDURE TO CREATE THE DOGHOUSE:

Reference Image provided for the construction of two doghouses:

It is just a reference image and doesn't exactly adhere to all the design rules but we have to take the reference image into account to create these doghouses on our plastic component.

DRAFT ANALYSIS WITH RESPECT TO THE MAIN TOOLING AXIS:

First, we'll place the compass on the Main Tooling Axis as shown below:

DRAFT ANALYSIS WITH RESPECT TO THE SIDE CORE AXIS:

Now, the inner section of the doghouse is needed to clear along the side core axis and hence now we'll place the compass on the Side Core Axis and perform the draft analysis as shown below:

From the above image, we can see that the draft analysis was successful and hence our doghouse will get cleared along both the Main Tooling Axis as well as the Side Core Axis.

Now, using Boolean Operations, we're going to assemble these doghouses with our main plastic component and create the final part as shown below: