Switch Bezel Design

DESIGNING CLASS A, B & C SURFACE OF SWITCH BEZEL

OBJECTIVE

Create the Switch Bezel Plastic component through the given Class-A surface, and create tooling axis, perform draft analysis and also create Class-B surface& Class-C surface.

INTRODUCTION

The Draft allows the part to easily eject from the mold. The draft angle is to reduce friction between the core, cavity and part and it also avoid the damages. The minimum draft angle is 0.5 degree and the most common draft angle used in the plastic design is 3 degrees.

In CATIA the draft analysis is performed based on colour ranges identifying zones on the analysed element where the deviation from the draft direction at any point, corresponds to specified values.

Tooling direction is the main element that to be consider while designing a plastic component. In moulding machine the arrangement is given to open the mould along the direction. It is the direction in which the core and cavity opens.

CLASS A SURFACE

1.Visible surface and aesthetic look
2.Surface with textures
3.Surfaces provided by customer(OEM)
4.Don't have any features like(rib ,snap ,bosses etc.) on class A surface.
5.Class A surface is made from scanned data with different software like alias etc..
6.Surfaces which is having CURVATURE CONTINUITY IS CALLED class-A.

CLASS B SURFACE

1.Invisible Surfaces.
2.Surface mostly don't have textures
3.Surface need to be create according to class-A surface.
4.Having all features(Rib, boss, snap etc.) in B-side surface only.
5.Surfaces which is having TANGENT CONTINUITY IS CALLED class-B

CLASS C SURFACE

Which join both Class-A and Class-B Surface

METHODOLOGY

GIVEN CLASS – A SURFACE (BASE BRACKET)

PROCEDURE

First the continuity should be checked in the given Class A surface. By using the boundary option

Tooling axis

• Extract the base of the switch bezel using multiple extract option. Create a point on it using on surface option
• Insert axis system in the point, create a sketch on it using YZ plane
• Make intersection on it, draw two inclined line on the intersection
• Using the bisecting line option by selecting the two inclined lines and the point create a line which is the tooling axis y
• By using the same method create a sketch on the XZ plane make intersection on it. Draw a line on the intersection and draw an another line which is 5 to 6 degrees from the first line. Which is the tooling axis x
• Create a bisecting line using the X & Y Tooling axis we get the Tooling axis and publish it

TOOLING AXIS

CLASS B Surface creation

• Create the Class B surface one by one first the Bezel rest surface (Pink colour) extract the surface, untrim the surface Repeat this operation for the walls and the base surface of the switch bezel
• For Base and wall, offset the surface for 2.5mm which is the thickness of the component.
• Trim all the surface to form the Class B surface
• Now perform the fillet operation

CLASS B SURFACE

CLASS C Surface creation

• The edges of the Class A surface is extracted using the multiple extract and then converted into smooth curvature to avoid the patches.
• Sweep (with draft direction) option is used selecting the smooth curves as the guide curve and tooling axis as the direction and draft angle as 3deg
• Trim the sweep that created and join it with the Class A surface
• Then trim the Class C with Class B surface

CLASS C SURFACE

Solid body creation

• Before creating solid body the surface part have to be checked weather is there any gaps in between it
• If there any gaps it can be joined using extrapolation and trim option.
• Define the part body and use close surface option make it a solid body

FINAL SOLID BODY

Draft analysis

• For plastic parts the Nominal draft angle is 3deg, but even 7deg is allowed for the subassemblies like ribs and slots
• INSERT - ANALYSIS - FEATURE DRAFT ANALYSIS
• First the compass is moved to the part (the compass should be placed on the tooling axis) which used to define the new current draft direction, then lock the draft direction using the lock icon
• The colour chart indicates the various condition of the draft angle . the green colour indicates that the part passes and the and can be used for the further operations
• By using the analysis under the running point icon we can check draft angle at the various surfaces of the component
• There are two modes in the Draft analysis quick mode and fully detailed mode
• If the surface satisfies the 3Deg then it shows in green in colour if not appears in red colour

CLASS A DRAFT ANALYSIS

SOLID BODY DRAFT ANALYSIS

Feature Tree

CONCLUSION

The Class B, Class C and the solid body of the switch bezel is created from the given Class A surface and the draft analysis is performed