Coin Holder Design

OBJECTIVE: To create the Coin Holder's Plastic component using the Class A Surface that is provided.

Firstly, we have to create the required Tooling-Axis for the given Class A Surface while meeting the requirements of the necessary Draft Angle & then perform the Draft-Analysis Operation on the Class A Surface itself.

After that, we have to create the required Class B & Class C Surfaces using which we have to create the Final Plastic Component and perform Draft Analysis on it.

MAIN REPORT:

Types of Surfaces and their Importance for an Automotive Plastic Designer:

• Class A Surface: Class A is an aesthetic surface with the highest quality finish. Most Class A Surfaces for an Automotive Component are made using 'Autodesk-Alias' based on the final Concept-Sketch. All Class A surfaces should have 'Curvature-Continuity' which means the continuity between the surfaces should share the same boundary. It is taken as a reference by the Automotive Plastic Designer to create 'Class B' and 'Class C' Surfaces.

 

• Class B Surface: The Class B Surface resides below the Class A Surface at a certain thickness. It is created using Engineering Principles that consist of all the necessary features such as Ribs, Bosses, Snaps, etc. This surface isn't visible to the observer from the outside.

 

• Class C Surface: The Class C Surface is the surface created between the Class A and Class B surfaces to join them with each other.

 

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

Our Class A Surface:

 

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' up to 0.003mm following the industry standard. 

 

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 on the Class-A surface and check if there are any internal boundaries other than the outer edge. 

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:

To create our Main Tooling Axis, we'll begin by using 'Extract Command' from the 'Operations Toolbar'  & Extract the Base-Surface from the Bin-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 point 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.

Before that, we're going to create an Intersection between our Class A Surface and our Bisecting Plane as shown below:

Now, we'll hide the Class A surface and inspect the intersection for any Draft-Angle using the Measure Tool.

  

As we can see from the above image that the wall of the component contains a Draft-Angle of 3.2 degrees and hence to find the Main Tooling Axis we'll start a positioned sketch and take this intersection as a projection using 'Project 3D Element' command from the 'Operations Toolbar' in Sketcher Workbench. Then we'll draw two new lines on the lines meant for the walls and draw a 'Bisecting Line' between them to create the 'Main Tooling-Axis' as shown below:

   

Therefore, the Green-Line shown in the above image represents our Main Tooling Axis.

 

DRAFT ANALYSIS ON THE CLASS A SURFACE:

Next, We will perform a Draft Analysis on the Class A Surface itself:

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'.

It is evident from the above image that the Draft-Analysis on our Class A Surface was successful and the component is feasible to manufacture.

 

PROCEDURE TO CREATE THE CLASS B SURFACE:

1. SIDE WALLS:

First, we're going to extract 4 surfaces as shown in the images below using 'Extract Command' from the 'Operations Toolbar' with 'No Propagation' mode while avoiding the filleted surfaces.

Then, we'll untrim these extracted surfaces using the 'Untrim Command' under the 'Join Command'.

Now, we're going hide all the parents and extrapolate these untrimmed surfaces using 'Extrapolate Command' while defining the 'Continuity-Type' as 'Curvature' & Propagation-Type as 'Point Continuity'.

Now, we'll trim all the unnecessary edges using the 'Trim' command from the 'Operations Toolbar' as shown below:

 

Now, the desired thickness of the wall is 2.5mm and hence we're going to use the Offset-Command to offset these side walls.

 

2. BASE:

We're now going to create the Base-Surface for our component and to start the procedure we'll unhide the Class A Surface and use the 'Extract' command to extract the base surface and the surface adjacent to the base as shown below:

Then, we'll untrim these extracted surfaces using the 'Untrim Command' under the 'Join Command'.

Now, we're going hide all the parents and extrapolate these untrimmed surfaces using 'Extrapolate Command' while defining the 'Continuity-Type' as 'Curvature' & Propagation-Type as 'Point Continuity'.

 

Now, we're going to offset these two surfaces in the opposite direction of their Class A Surface counterparts as that is our limit.

 

We'll also have to create an additional section for the base surface for which we'll unhide the Class A surface and extract the required surfaces as shown below:

UNTRIM OPERATION:

EXTRAPOLATION:

TRIM OPERATION:

2.5 MM OFFSET: 

FINAL TRIM FOR BASE:

 

3. TOP WALLS:

Now, we're going to create the Top-Walls. Once again we'll unhide the Class A Surface and this time we'll use 'Multi-Extract Command' as these walls are filleted.

 

Then, we'll extrapolate these surfaces using the  'Extrapolate Command' while defining the 'Continuity-Type' as 'Curvature' & Propagation-Type as 'Point Continuity':

 

4. APPLYING FILLETS:

After that, we'll measure the fillet values from the Class A Surface to apply to the Class B Surface.

The most important factor to take into consideration while providing the fillet values from Class A Surface to Class B Surface is that the Wall Thickness should be uniform at all points. 

If we measure the value of the fillets directly from the Class A Surface then we'll not get accurate values as the original edges are trimmed with respect to other surfaces while creating the Class A Surface. Hence, we'll use the 'Extract Command' to extract those surfaces and then untrim them using the 'Untrim Command' to recreate the actual edge of the filleted surface. When that is done, we can measure the actual value of the fillet using the measure tool. The whole process is shown below:

A. Value of the Edge-Fillet at one corner of the Side-Wall when measured from the Class A Surface itself:

 

B. Extracting the filleted surface using the 'Extract Command' with 'No Propagation Mode':

 

C. Using 'Untrim Command' to recreate the original filleted surface using which we can find out the actual value for the fillet:

From the above image, we can notice that the original value of the untrimmed surface is 10.077m instead of 16.08mm.

Now, when the Class B Surface is heading outward with respect to the Class A Surface then we have to add the value of wall thickness to the fillet value to maintain Uniform Wall-Thickness.

If we take the fillet value measured directly from the Class A Surface and add 2.5mm to it then while inspecting the wall thickness using the measure tool, we'll able to notice that the wall thickness is nowhere near 2.5mm as shown below:

 

We can notice from the above image the Wall-Thickness is 0.206mm instead of 2.5mm. 

Now, when we use the value of the fillet taken from the extracted and trimmed surface which is 10.077mm, and add 2.5mm to it and provide that fillet value to the edge of the side wall we'll notice that the wall thickness will be equal to 2.5mm as shown below:

We'll apply this method to all the rest of the edges to ensure that our wall thickness is uniform throughout the component.

 

From the above image, we can see that all the filleted surfaces on the Class B Surface are having 2.5mm distance from the Class A Surface as the Wall Thickness.

 

TRIMMING INITIAL COMPONENTS OF THE CLASS B SURFACE TOGETHER:

Now, we're going to trim the initial components of the Class B Surface together. We'll start the procedure by trimming the base and side walls together as shown below:

Next, we're going to trim the Top-Wall with the above surface as shown below:

 

Using the Dynamic Sectioning Tool we can inspect the Wall-Thickness between Class A &Class B Surfaces as shown below:

 

 

5. OUTER FLANGE:

Now, we're going to create the Class B Surface for the Outer Flange section.

We'll start the procedure by extracting the outer surface of the flange using the 'Multi-Extract Command' as shown below:

Then, we'll create a boundary along the inner section of the flange using the boundary command with limits as shown below:

Then, we'll extrapolate the surface along the newly created boundary as shown below:

 

After that, we'll offset it by 2.5mm to account for the Wall-Thickness as shown below:

 

Now, we'll unhide the Class A Surface once again and extract the rest of the surfaces needed for the outer flange using Multi-Extract Command as shown below:

 We'll extrapolate it and then offset it by 2.5mm as shown below:

Now, we'll trim both the offsets with each other:

Next, we'll create another boundary using limits for the other side of the outer flange:

We'll extrapolate the surface along the newly created boundary as shown below:

 

Finally, we'll trim this surface with our initial trim surface that includes the base, side walls, and top walls as shown below:

 

 

INTERSECTION BETWEEN CLASS A & CLASS B SURFACE:

 

 

Before moving forward to create the Class C Surface, we'll work on few things remaining in the Class B Surface.

While inspecting our Class B Surface with respect to the Class A Surface we came across a surface that was protruding outside and needed to be fixed. That protruding surface is shown below:

So now, to fix this we're going to follow the steps shown below:

First, we'll extract the flat surface adjacent to it.

Then, we'll untrim and extrapolate it as shown below:

After that, we're going to offset it by 2.5mm

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

 

Now, we're going to provide fillets for our Class B Surface as shown below:

1. First Fillet:

2. Second Fillet:

3, Third Fillet:

 

PROCEDURE TO CREATE THE CLASS C SURFACE:

We'll begin by unhiding the Class A Surface and creating a boundary as shown below:

We'll smoothen the boundary using Curve Smooth Command as shown here:

Then, we'll select all the surfaces along the boundary using the Multi-Extract Command as shown below:

Now, we'll perform a Sweep Operation using the Extracted-Surface and the Boundary.

First, we'll click on the Sweep Command and then under Sweep Surface Definition we'll select the Subtype as 'With Reference Surface'.

Then, we'll select the smoothend boundary as our Guide-Curve and the extracted surface as our Reference Surface. We'll insert the value of angle as 90 degrees as we want the Sweep-Surface to be Perpendicular our Main Tooling Axis. Also, We'll insert the value of length as 4mm and click on OK.

Now, we'll trim the Class C Surface with Class B Surface as shown below:

Finally, we'll use the JOIN COMMAND to join this trimmed surface with the Class A Surface to obtain the final Closed Surface.

Wall Thickness is uniform everywhere with a value of 2.5mm which can be measured using the Measure Tool.

We'll use the boundary command to check if there's any boundary present on the final surface.

  

It is evident from the above image that our final surface has no boundary and hence it is correct.

Now, we'll move to the Part-Workbench and create a solid body using the 'Closed Surface Command'.

 

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 the compass 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 anywhere on the surface of the Final Part the results of which are 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

 

INVERSED DRAFT-DIRECTION:

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

 

 

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:

 

 

TREE STRUCTURES:

1. CLASS A SURFACE:

 

2. MAIN TOOLING AXIS UNDER CONSTRUCTION:

 

3. SIDE WALLS UNDER CLASS B SURFACE:

   

 

3. BASE UNDER CLASS B SURFACE:

   

 

4. TOP WALLS UNDER CLASS B SURFACE:

 

5. INITIAL TRIMS:

 

6. OUTER FLANGE:

 

7. FILLETS:

 

8. CLASS C SURFACE:

 

9. CLOSED SURFACE & DRAFT ANALYSIS:

 

10. PUBLICATIONS: