Week 9 - Project 1 - Door Trim Lower with Engineering Features

Week 9 - Project 1 - Door Trim Lower with Engineering Features

AIM

Create the Door Trim Lower 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. 

Create the Heat Stakes and the locators considering the design rules mentioned in the video for the door applique.   

Requirements

• Screenshots of the completed design in various orientations (Isometric, Front, Side, and Top View)
• CATpart should be submitted as an attachment

REPORT

Class A Surface

Class A surface is a outer styling surface on which design engineer starts designing components.

Class B Surface

This surface is created by offsetting the Class A surface. The offset value is equal to the thickness of the component. On this surafce all the engineering features are provided.

Class C Surafce

The surface joining Class A and Class B in the tooling direction is known as Class C surface.

Locators

2 way or 4 way locators are used in plastic component to restrict the movement of component or degrees of freedom in desired direction.

Heat Stakes

Heat staking is the process of joining two dissimilar materials together. In heat staking we use local heating and cooling to raise the temperature of plastic components and allow plastic reforming to be carried out. This reforming is converted into a shape that will hold the secondary component.

Tooling Axis

Tooling axis is a direction in which core and cavity opens and closes. Draft angle is provided with respect to the tooling axis. While creating mold component from Class-A surface, we need to decide the tooling direction. It can be decided by visual inspection, deciding complex surfaces and bisecting method.

Tooling Axis Creation- Bisecting Method

• First check for the discontinuity of the surface received by join or boundary command. Then visual observation is done to decide which direction will be more feasible to create component.
• Few surfaces are identified which can create concern over draft angle
• A reference point is created in center of the bottom surface. And Axis system is created at that point. 
• Two different cross section profiles are formed using intersection with plane.
• For first profile in xy plane, Lines are drawn on the concerned boundary intersection profile. Then line is drawn bisectiong these two lines.
  
• For the second intersection profile in xy plane same procedure is followed.
  
• A bisecting line is created from the two lines created earlier with intersection profile. This bisecting line refered as Tooling axis line and this method is known as Bisecting method to create tooling axis.
  
  
  

Draft Analysis

To reduce the risk of damage to parts and tool while ejecting from mold a draft angle is provided to walls which are parallel to the tooling direction. It assists with releasing the part from mold.

To perform Draft analysis in Catia, Draft analysis feature is used. For that First tooling Direction decided. Then make sure material view mode is used. After opening the window, align the compass with the tooling axis by dragging it on the axis. Then click on the surface or the body on which draft analysis is need to perform. In the bottom black colour window provide the minimum draft angle and then match the body color with this color scale. Green indicated draft angle is more than minimum draft angle. If it is blue then it is between 0 to minimum draft angle. And red denotes it is less than zero. By this way we can identify the areas with draft angle less than minimum draft angle and work on that area by changing tooling axis angle.

         

Procedure

• Check for Discontinuity. If any, join the surface. And Publish it as CLASS A surface
• Identify concern planes. Create line in every concern planes. From the these line create bisecting line ie. final Tooling axis.
• Perform Draft analysis on Class A surface in the Tooling Direction
• Create Class B surface by offseting Class A surface and join them by trimming. Fillet Edges. Or use fill by creating close profile.
• Create Class C surface by extracting boundary of class A surface and sweep it by minimum draft angle along the tooling direction.
  
• To create final closed surface body, join and trim all three surface together and finish by giving remaining fillets.
  
• Convert this surface body into Solid body by Close Surface Tool
  
• Next step is to create locator. Create a iso-constraint sketch, use pad, draft, and fillet features and add to the main body.
  
• In similar manner create heat stake and translate it to the given points.
  
• Perform Draft analysis again on the Solid body.

RESULTS 

Draft Analysis

1. Class A Surface
   
   Class A surface Draft angle is more than 3 degrees with respect to tooling direction.
   
   
2. Solid Body
   
   In Solid body Draft Analysis, The class A surface shows the Draft angle more than 3 degrees. While Bottom surface (Class B) has negative draft angle. Class C surface has some mix draft angles. Some surface changes needs to be made by informing styling team.
   
   For Heat stakes and locators, all the surface pass the draft analysis test. It has minimum draft angle 0.5 degrees on walls. Please refer the colour chart.

Draft Analysis Views

Front	Side
Top	Isometric

Conclusion

Plastic compponent Door Lower Trim is created from given Class A surface in CATIA V5. The Tooling Axis created for the Class A surface, meets the requirement of Draft angle. Heat stakes and 4 way locators are created on the body And Draft analysis is performed on Solid Plastic Component too.