Core & Cavity Design

OBJECTIVE: To create the Core & Cavity blocks for the Switch Bezel designed in the earlier challenge. 

 

Guidelines for the Tree Structure:

1. Ensure Proper Tree Structure.
2. Geometrical sets should have a proper name based on the sketches present inside of them.
3. All the sketches should be created under the Geometrical set 
4. Use the Close Surface feature to make a solid body from the surface.
5. Publications: Use the publication option and publish the below:

• Tooling Axis
• Switch Bezel Solid / Surface body
• Parting Line and Parting Surface

 

We have already designed the Switch Bezel in an earlier challenge and the link for that is given below: 

https://skill-lync.com/student-projects/week-8-challenge-2-switch-bezel-design-728

We will eventually design the Core and Cavity that the Injection Molding Machine will use to manufacture this plastic component. 

 

PROCEDURE TO CREATE THE MAIN TOOLING AXIS:

To create our Main Tooling Axis, we'll begin by using 'Extract Command' from the 'Operations Toolbar'  & Extract the Base-Surface from the Pocketed-Section of our Class A Surface using 'Propagation Type' as 'No Propagation' as shown in the image below:

Now, we'll create a point over that extracted surface using the point command while defining our 'Point Type' as 'Only Surface'  and then we'll state the Distance as '0mm' that will allow us to create a point right at the middle end of that surface as shown in the images below:

 

Instead of using the 'Default Planes' we will introduce an 'Axis-System' right at that point as shown below:

 

After deploying our new Axis-System, we have to create 'Clearance Lines'  that can be used eventually to create the Main Tooling Axis.

Hence, we are going to start the procedure by creating a 'Positioned-Sketch' along the ZY-Direction taking the point created before as our 'Projection Point'. 

Then, we’re going to create an 'Intersection' using the 'Operations Toolbar present in the 'Sketcher Workbench', and then we're going to use the 'Visualization Toolbar' to go to the 'No 3D Background' mode to work on our Sketch as shown in the image below:

We are doing all this to create a 'Clearance-Line' along the Y-Direction of the Class A Surface.

Now, we'll create two new lines over the lines shown below between these two surfaces so we can eventually create a mean line between these two opposite surfaces. 

Now, we'll hide all the projected lines and then create a Bisecting-Line using the 'Profile Toolbar' under the 'Line Command'. The Bisecting Line that is created will be more extended than we need and therefore we'll make it shorter using the 'Trim Command' as shown below:

After this, we'll convert the lines used to create the Bisecting Line into Construction Elements.

Then, we'll create a Clearance-Line along the X-Axis for which we're going to create a new sketch.

We'll start by creating a 'Positioned Sketch' along the ZX-Plane using the Projection Point we used for the previous sketch. 

We will use the command 'Cut the Part by Sketch Plane' from the 'Visualization Toolbar' and take an Intersection of the Class A Surface.

 

Then, we'll draw a line on the only surface we have in the X-direction and since we don't have an Opposite-Surface, we'll draw another line from the centre point at an angle of 3 degrees that is required as our 'Draft-Angle.

 

Finally, we'll have 2 Bisecting-Lines acting as Clearance-Lines along X & Y-Axis as shown below:

 Now, we'll create the 'Main Tooling-Axis' using these 2 clearance lines to make the final Bisecting-Line. 

 

When we view the Main Tooling Axis from the Normal View, we notice all the Surfaces as shown in the image below and that tells us that the required Draft Angles are present and our Tooling Axis is correct.

 

PROCEDURE TO CREATE THE CORE BLOCK:

First, we'll create a boundary along the edge of our Class A Surface as shown below:

Then, we'll extrapolate it as shown below:

Now, we'll use the Class C Surface to Trim it with our extrapolated Class A Surface but before doing that we'll create an intersection between them to check if a trim operation is feasible between them as shown below:

Initial Class C Surface:

Intersection Between Class C Surface & Extrapolated Class A Surface:

From the above image, we can see that there's a region in the intersection between both of these surfaces where they're not intersecting with each other; hence we're going to perform an extrapolate operation in the region so that they can intersect each other completely.

Extrapolating the Class C Surface:

After that, we'll trim them with each other as shown below:

Now, we're going to cut it with the Class B Surface as shown below:

We'll create the Parting Line and the Parting Surface:

Parting Line: We'll create an intersection between the Trimmed Surface shown above and the Class B Surface. The parting line is where the two halves of the mould meet around the parameter of the part. All parting lines need to seal properly when the mould is clamped in a moulding machine. It exists outside the component as shown below:

 

Parting Surface: A parting surface is a separable contact surface that separates the mould to remove the product and the congealed material from the pouring system. The parting surfaces provide support to the mould during the injection process and help to distribute the molten plastic evenly. It is important to design the parting line and parting face carefully to minimize potential defects in the moulded part.

In our case, we made it by using the split command on the surface of the core block along the parting line as shown below:

Note: Parting Surface is always outside of the Component's Area. 

 

Now, we'll create a sketch for the Core Block's walls as shown below:

Then, we'll use the extrude command to extrude the sketch with respect to the Main Tooling Axis as shown below:

 After that, we'll perform a Trim Operation with the earlier trimmed surface of the component as shown below:

We'll use the Fill Command to create a cover for the base section of the Core Block as shown below:

Then, we'll join it with the rest of the surface to create a closed body as shown below:

Finally, we'll move on to the Park Workbench by using the Closed Surface Command from the Surface-based Features Toolbar, we'll create a solid body for the Core Block:

We'll create an intersection between these surfaces to understand the relation between them better.

 

PROCEDURE TO CREATE THE CAVITY BLOCK:

For the Cavity Block, we'll perform the Extrude Operation once again using the same sketch we used earlier to create the walls for the Core Block with respect to the Main Tooling Axis as shown below:

To exclude the region for the component, we're going to trim it with the Class B Surface as shown below:

We'll use the Fill Command once again to create the base surface for the Cavity Block and then we'll join it with the previously trimmed surface as shown below:

Again, we'll move on to the Park Workbench by using the Closed Surface Command from the Surface-based Features Toolbar, we'll create a solid body for the Cavity Block:

 

Finally, we'll use the Translation Command from the Transformation Features Toolbar to translate both Core and Cavity Block 50mm in the opposite direction while the solid plastic component stays in the middle as shown below:

 

DRAFT ANALYSIS FOR THE PLASTIC COMPONENT, CORE BLOCK AND THE CAVITY BLOCK:

DRAFT ANALYSIS ON THE SWITCH BEZEL PLASTIC COMPONENT:

Finally, we'll perform the Draft Analysis for the Final Part in the Part Workbench:

We'll click on the 'Draft Analysis' under the 'Analysis' Toolbar in the Part Workbench.

Then, we'll click on the Compass Symbol under 'Direction' which stands for 'Use the Compass to define the new current draft direction'.

We'll drag and place the compass on the Main Tooling-Axis.

Then, we'll select 'Show or Hide the Color Scale' under 'Display' and define our Draft-Angle as 3-Degrees. After that, we'll click on the surface of the Final Part to show the results as shown below:

In the Draft-Analysis,

Green Colour stands for regions where the Draft Angle is more than 3 degrees,

Blue Colour stands for regions where the Draft-Angle is between 0-3 degrees, &

Red Colour  stands for regions where the Draft Angle is lower than 0 degrees

 

VIEW FROM INVERSED DRAFT DIRECTION: 

It is evident from the above images that the Draft Analysis is successful and the Final Closed Surface Part is feasible to manufacture. 

 

DRAFT ANALYSIS ON THE CORE AND CAVITY BLOCK:

1. CORE BLOCK:

 

2. CAVITY BLOCK:

 

3D VIEWS OF THE FINAL PART WITH PROPER COLOR CODE OF THE DRAFT ANGLE IN VARIOUS ORIENTATIONS:

1. FRONT VIEW:

 

2. TOP VIEW:

 

3. ISOMETRIC VIEW:

 

3D VIEWS OF THE CORE BLOCK IN VARIOUS ORIENTATIONS:

1. FRONT VIEW:

 

2. TOP VIEW:

 

3. ISOMETRIC VIEW:

 

3D VIEWS OF THE CAVITY BLOCK IN VARIOUS ORIENTATIONS:

1. FRONT VIEW:

 

2. TOP VIEW:

 

3. ISOMETRIC VIEW:

 

 

TREE STRUCTURE FOR THE CORE & CAVITY DESIGN:

1. CORE DESIGN:

 

2. CAVITY DESIGN:

 

3. PART LINE & PARTING SURFACE:

 

4. SOLID BODIES & DRAFT ANALYSIS:

 

5. PUBLICATIONS:

 

THE REQUIRED CATPART IS ATTACHED WITH THIS REPORT IN A ZIP FILE.