Week 8 - Challenge 5 - Core & Cavity Design

AIM:

 

To create the core and cavity for Switch Bezel component through the given Class-A surface using Catia V5.

 

OBJECTIVE:

 

• Create a tooling axis following the OEM standard
• Making the Surface into Solid Body
• Part Thickness : 2.5 mm
• Performing the draft analysis to the component

 

INTRODUCTION:

                                                                                       

Cavity and core are the moulding elements that give shape to the moulded part.  Cavities are normally designed in the fixed half of the mould base, the injection side. Sometimes, however, cavities may be mounted on the moving side.  Cores are normally designed on the moving half of the mould base.

 

METHODOLGY:

 

• Creating the Tooling Axis

 

The tooling direction is used to find the direction in which the part is removed from the core and cavity. The draft angle should be positive to the tooling axis to manufacture the component easily. The step by step procedure of creating the tooling axis is given below.

 

Step: 1

 

Creating the point on surfaces respectively also extract the surface of the component.

 

                                                        

 

Step: 2

 

Now creating the intersection to the Z-Y and Z-X direction of the surface as shown below.

 

                                                        

                                                        

 

Step: 3

 

Now creating the bisecting lines for the intersection lines to the tooling axis for both Z-Y and Z-X axis. Once we get the bisecting lines for both axis now bisect that both bisecting lines to get min tooling axis.

 

                                                         

 

Finally we get our main tooling axis for the Switch Bezel component.

 

                                                         

 

• Creating the Core as B Surface.

 

Step: 1

 

Creating the B SURFACE by extracting the class A surface, by each surfaces separately, it is untrimmed and extrapolated to certain distance using point continuity for uniform extension all over the boundary as shown below.

 

                                                        

                                                        

 

Step: 2

 

The extrapolated surface are offset for 2.5 thickness and it is trimmed out to form exact shape.

 

                                                     

                                                     

 

Step: 3

 

Trimming the Side wall of the bin part to the main surface to get exact component as class A surface it is offset to the 2.5 mm distance.

 

                                                    

 

Step: 4

 

Top surface is extracted, offset, extrapolated and trimmed along the side walls as shown below. Edges are again fillet for radius 15mm to get aesthetic component.

 

                                                           

                                                           

 

 Fillet areas are examined whether we created to offset for the class A surface for the thickness as shown below.

 

                                                      

 

Finally we achieved the B class surface by extracting in the Class A surfaces.

 

                                                       

 

Step: 5

 

Once we get the B surface, now we are going to make rectangular block by sketching the part respective the B surface area to cover it.

 

                                                      

 

Step: 6

 

Now extruding the rectangular block to make core body for the component of B surface, and its trimmed with it. To get the actual core block as shown below.

 

                                                          

                                                          

                                                        

 

• Creation of C Surfaces:

 

Step: 1

 

Extracting the boundary of Class A surface and it is make into smooth curves to sweep the curves by using support surface to the tooling axis and to 3 degree draft respectively.

 

                                                    

                                                      

 

It is trimmed with b surface to make Class C surface as shown below.

 

                                                     

 

Step: 2

 

Once the all surface joined together it extruded and trimmed to certain distance to trim with Class C surface to get cavity block. Finally we created cavity block with Class C surface.

 

                                                    

                                                    

 

Creating the Parting Line and Surface:

 

Using the Class B and C surface going make the intersection to get the parting line. Its indicated in yellow colour dotted line for better visualization.

 

                                                       

 

For parting surface, we going to create the boundary on edges of component and it is extra polated and trimmed to the C surface to the separate parting surface as shown below.

 

                                                      

                                                       

                                                      

 

Making the Core and Cavity Component:

 

We created the core and cavity block. Now we ensure the whether it is perfectly matches with plastic component by intersecting the all the component. The color variation of core and cavity, Parting Line and Surface has been displayed for easy understanding.

 

                                                          

                                                          

                                                         

 

• Performing Draft Analysis:

 

The Draft Analysis command enables you to detect if the part you drafted will be easily removed. This type of analysis is performed based on colour ranges identifying zones on the analysed component where the deviation from the draft direction at any point, corresponds to specified values. This rule of thumb applies to parts with mold depths of up to 2 inches. At this size, draft as low as 1½ degrees will allow for an easy, non-damaging release from the mold when the expected shrinkage of the thermoplastic material occurs.

It’s also important to remember that draft angles are just one component of an effectively designed injection molded piece. Design for manufacture is one of the easiest ways to improve the quality and efficiency of your injection molding process, and it never hurts to stay up to speed on all injection molding best practices.

 

1. Draft Analysis for Class A surface:

 

Step: 1

 

Initially we perform the draft analysis to the class a surface to ensure that we have good quality of surface to make Class B and C surface to achieve the same kind of quality surface. First we have to set the compass on the main tooling axis to get the direction of core and part moves along as shown below.

 

                                                          

 

Step: 2

 

Once compass is locked in the axis, directly click on the surface it will appear quality of draft surface whether, it is pass or failed. Here the draft angle is given as 3 degree. Hence we achieved green colour on top surface. Hence it accepts the draft angle for the surface, so we build good quality component.

 

                                                             

 

Step: 3

 

Now we check colour variant scale to ensure the maximum and minimum area draft angle is achieved by displaying by green, red and blue colour respectively. If the surface appears red in colour while analysing it is not accepted.

 

                                                          

 

Step: 4

 

We can check the angle of draft given to surface by using draft tool analysis just point the over the surface where we have check angle of given draft to the component as shown below.

 

                                                         

 

2. Draft Analysis for final component:

 

Step: 1

 

First we have to set the compass on the main tooling axis to get the direction of core and part moves along as shown below.

 

                                                        

 

Step: 2

 

Once compass is locked in the axis, directly click on the surface it will appear quality of draft surface whether, it is pass or failed. Here the draft angle is given as 3 degree. Hence we achieved green colour on top surface. Hence it accepts the draft angle for the surface, so we build good quality component.

 

                                                       

 

Step: 3

 

Now we check colour variant scale to ensure the maximum and minimum area draft angle is achieved by displaying by green, red and blue colour respectively. If the surface appears red in colour while analysing it is not accepted.

 

                                                         

 

Step: 4

 

We can check the angle of draft given to surface by using draft tool analysis just point the over the surface where we have check angle of given draft to the component as shown below.

 

                                                         

 

Screenshot views of coin holder with draft analysis:

 

Front View:

 

                                                          

 

Side View:

 

                                                       

 

Top View:

 

                                                       

 

Isometric View:

 

                                                        

 

Publication:

 

                                                        

 

Conclusion:

 

Creation of the Core and Cavity for switch bezel has been successful done for the thickness of 2.5 mm, it has been converted from surface into solid body. The tooling axis has been created according the OEM standard. Drafting Analysis has been performed and results has been updated in step by step methodology.