Challenge

Week 11 - Final project

AArun Muraleedharan30 Aug 2022

AIM

Create the Door Trim Plastic component through the given Class-A surface and master section and perform Draft analysis.

THEORY

CLASS A SURFACE: Class A surface is a surface made by the designer specially in automotive design which is the aesthetic part of a body and is given as an input to the plastic designer to work on it.

CLASS B SURFACE: It is a surface which comes below the class A surface with a particular thickness. This surface contains engineering features of a model.

CLASS C SURFACE: It is the surface which joins class A with class B surface.

MASTER SECTION: Master sections are the guides for design requirements which decide the component packaging after technical (Styling, Concept or Class-A) surfaces. Creating this master section should need 5 to 6 years of experience. This helps you to decide the feasibility, clearance, the packaging and the fixation strategy before working it on a 3D.

TOOLING AXIS: Tooling axis is the direction in which the core and cavity opens. If we are using proper tooling axis, we can avoid adding side cores thus the cost of manufacturing the component can be reduced.

It is defined as the direction in which the mould/core and cavity open. Selection of the direction of the tooling axis depends on the ease at which components can be easily ejected.

Generally tooling axis is decided from the natural axis of the design, that is, tooling axis is analysed with the x, y and z axis of the system. If the axis doesn’t clear the draft analysis, the next step is to look for the surface in which the drafting axis can be created in such a way that the axis is normal to the surface taken. These are the methods of deciding tooling axis. Bisecting method is the least used method.

DRAFT ANALYSIS: From draft analysis, we can verify draft angles, examine the angle changes within a face, as well as locate parting lines, injection and ejection surfaces in parts.

It is an important feature in Catia which helps the user to analyse the draft on various surfaces. The draft analysis toolbar provides two modes for analysis of the draft, first is the quick analysis which basically has three colours (green, red, and blue) for analysing on the other hand other option is the full analysis mode which enables a few more details into the draft and is used in the complex components.

Draft analysis in Catia:

Step 1: Ensure that customize view parameter is enabled and material mode is opted in view mode customization.

Step 2: Now go to insert > analysis > feature draft analysis.

Step 3: Drag axis bar to the tooling direction of part.

Step 4: Check for draft.

Surface will be in green if the draft angle is more than 3 degrees, blue if draft angle is between 0 to 3 degree and red if draft angle is less than zero degree.

Three degree is the nominal value for draft, whereas 0.5 degree can also be manufactured at ribs.

ENGINEERING FEATURES

RIBS: Ribs are thin wall-like structures that add support and rigidity to injection molded parts. They are thinner than primary walls and are used to support these walls, as well as bosses, by running perpendicular to these structures. Ribs are often used to replace thick wall sections to avoid sink marks, warp, and voids.

SCREW BOSS: Boss features are commonly found in injection molding designs. They are used to aid in the assembly of molded parts by providing a channel for a screw. Because of its function, a boss must have sufficient strength to do its job. This dictates a minimum size for the feature.

LOCATORS: It is a feature which is used to arrest the degrees of freedom for the components being assembled.

HEAT STAKES: Heat staking also known as thermoplastic 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 can be used in a wide variety of applications.

Advantages of heat stakes are:

Simplification of machinery.
Reduced cost of machinery.
Multiple fastening points.
Allows higher density of welds compared to hot air cold form or ultrasonic welding.

DOG HOUSE: It is an engineering feature used in plastic trim design. It is used as a supporting feature. By using dog house, we can support the other engineering features like heat stakes, screw boss and locators to locate them at a certain height where we cannot violate the design rules for the features. By using doghouse, we can avoid sink marks in class A surface.

OBJECTIVES

Creation of Tooling axis
Creation of Class B and Class C surface from provided Class A surface.
Creation of solid part out of surface modelling using master section for reference.
Create engineering features as per the design guidelines in the industry and with master section.
Draft analysis of Class A surface and final part.

PROCEDURE

Given input files with master section:

BOTTLE HOLDER

Creation Of Class A Surface

Class A surface is obtained as the input.
Join all the surfaces to obtain Class A surface if different surfaces are given as input and ensure no gap is present between any surfaces. Thus, Class A surface is obtained and publish it. Here, the provided surface is completely joined and can be taken as class A surface.
Publish class A surface.

Creation Of Tooling Axis

Tooling axis is created by extracting a surface and creating a point over the surface and is given as an input for the line definition passing through the point along y component as its direction.
Publish Tooling axis.

Draft Analysis Of Class A surface

Draft analysis is performed over Class A surface and every surface is obtained as clearing.

Most of the surfaces obtained are green in color, which means that the surfaces are clearing the draft analysis.

Some faces of the surface are not clearing the draft. It is seen that the draft over those surfaces is having draft less than the nominal draft value of 3-degree. So, it is recommended for the class A designer to redesign the class A surface for obtaining all the surfaces cleared.

Creation Of Class B Surface

Now, Class B surface has to be created. For this surface should be offsetted for 2.5mm.
Publish class B surface.

Creation Of Class C Surface

Now class C surface has to be created and it is created from the boundaries obtained from the Class A surface. This boundary is provided as the input curve for sweep command. Using sweep command, class C surface is created.
Appropriate sweep is the provided considering the flash and considering manufacturing procedures. Surfaces are extrapolated if necessary.
Publish class C surface.

Creation Of Closed Surface

Now Class A surface and Class C surface is joined.

Now Class B surface is also trimmed with the obtained surface to get the closed surface.

Boundary check is done to check for any open boundaries in the part.

The closed surface then obtained moved to part design and close surface tool is used to obtain the part.

Engineering features are added to the component from the master section provided. The engineering features seems to be not enough from the master section. So, I had given more flanges for the better fit of the component.

Draft Analysis Of Plastic Component

The obtained part is draft analysed to check for the correctness of obtained model by following the draft analysis procedure mentioned above.

Screenshots Of The Solid Model With The Proper Color Code Of The Draft Angle In Various Orientations

Class A Surfaces obtained are all green in color, which means that the surfaces are clearing the draft analysis. The faces that are obtained in red will be clearing in core side, as the draft direction is reversed, those red faces will be turned to green which means those surfaces are also clearing draft analysis.

Engineering features are also created in such a manner that it also clears the draft analysis.

Parting line is created for the bottle holder. Parting line is the line which comes between the junction of joined class A and C surface with class B surface. It is the line that separates core and cavity.

UPPER MAP POCKET

Creation Of Class A Surface

Class A surface is obtained as the input.
Join all the surfaces to obtain Class A surface if different surfaces are given as input and ensure no gap is present between any surfaces. Thus, Class A surface is obtained and publish it. Here, the provided surface is completely joined and can be taken as class A surface.
Publish class A surface.

Creation Of Tooling Axis

Tooling axis is created by extracting a surface and creating a point over the surface and is given as an input for the line definition passing through the point along y component as its direction.
Publish Tooling axis.

Draft Analysis Of Class A surface

Draft analysis is performed over Class A surface and every surface is obtained as clearing.

All surfaces obtained are green in color, which means that the surfaces are clearing the draft analysis.

Creation Of Class B Surface

Now, Class B surface has to be created. For this surface should be offsetted for 2.5mm.
Publish class B surface.

Creation Of Class C Surface

Now class C surface has to be created and it is created from the boundaries obtained from the Class A surface. This boundary is provided as the input curve for sweep command. Using sweep command, class C surface is created.
Appropriate sweep is the provided considering the flash and considering manufacturing procedures. Surfaces are extrapolated if necessary.
Publish class C surface.

Creation Of Closed Surface

Now Class A surface and Class C surface is joined.

Now Class B surface is also trimmed with the obtained surface to get the closed surface.

Boundary check is done to check for any open boundaries in the part.

The closed surface then obtained moved to part design and close surface tool is used to obtain the part.

Creation Of Doghouse

Doghouse are created by following the design rules.
It is then made to closed body and is made to part model.
Shell operation is performed to get hollow structure and then coring is done in order to avoid sink marks in the class A surface.
Drafts are given for the surfaces as per design rules and proper fillets are also provided.
As per the given master section, ribs and supporting features are also added in the doghouse.

Then, the doghouse is added to the main body.

Draft Analysis Of Plastic Component

The obtained part is draft analysed to check for the correctness of obtained model by following the draft analysis procedure mentioned above.

Side core has to be created for the doghouse to get ejected. So, a side core axis is also created for checking the draft analysis of the component.

Minimum of 1.5-degree draft is provided and the B side engineering features are analysed. Green colour is obtained in the draft analysis, which indicates that the draft provided all are in correct direction.

Minimum of 0.5-degree draft is provided and the B side engineering features are analysed using the side core axis. Green colour is obtained in the draft analysis, which indicates that the draft provided all are in correct direction.

Draft Analysis Of Plastic Component

The obtained part is draft analysed to check for the correctness of obtained model by following the draft analysis procedure mentioned above.

Screenshots Of The Solid Model With The Proper Color Code Of The Draft Angle In Various Orientations

Engineering features are also created in such a manner that it also clears the draft analysis.

Parting line is created for the upper map pocket. Parting line is the line which comes between the junction of joined class A and C surface with class B surface. It is the line that separates core and cavity.

DOOR ARM REST

Creation Of Class A Surface

Class A surface is obtained as the input.
Join all the surfaces to obtain Class A surface if different surfaces are given as input and ensure no gap is present between any surfaces. Thus, Class A surface is obtained and publish it. Here, it was required to modify the class A surface and has to be created as per the master section. For this purpose, it has to be offsetted for 1mm for the cushioning of the component.
Publish class A surface.

Creation Of Tooling Axis

Tooling axis is created by extracting a surface and creating a point over the surface and is given as an input for the line definition passing through the point along z component as its direction.
Publish Tooling axis.

Draft Analysis Of Class A surface

Draft analysis is performed over Class A surface and every surface is obtained as clearing.

Most of the surfaces obtained are green in color, which means that the surfaces are clearing the draft analysis.

Creation Of Class B Surface

Now, Class B surface has to be created. For this surface should be offsetted for 2.5mm from class A surface.
Publish class B surface.

Creation Of Class C Surface

Now class C surface has to be created and it is created from the boundaries obtained from the Class A surface. This boundary is provided as the input curve for sweep command. Using sweep command, class C surface is created.
Appropriate sweep is the provided considering the flash and considering manufacturing procedures. Surfaces are extrapolated if necessary.
Publish class C surface.

Creation Of Closed Surface

Now Class A surface and Class C surface is joined.

Now Class B surface is also trimmed with the obtained surface to get the closed surface.

Boundary check is done to check for any open boundaries in the part.

The closed surface then obtained moved to part design and close surface tool is used to obtain the part.

Draft Analysis Of Plastic Component

The obtained part is draft analysed to check for the correctness of obtained model by following the draft analysis procedure mentioned above.

Screenshots Of The Solid Model With The Proper Color Code Of The Draft Angle In Various Orientations

Parting line is created for the door arm rest. Parting line is the line which comes between the junction of joined class A and C surface with class B surface. It is the line that separates core and cavity.

LOWER SUBSTRATE

Creation Of Class A Surface

Class A surface is obtained as the input.
Join all the surfaces to obtain Class A surface if different surfaces are given as input and ensure no gap is present between any surfaces. Thus, Class A surface is obtained and publish it. Here, the provided surface is completely joined and can be taken as class A surface.
Publish class A surface.

Creation Of Tooling Axis

Tooling axis is created by extracting a surface and creating a point over the surface and is given as an input for the line definition passing through the point along y component as its direction.
Publish Tooling axis.

Draft Analysis Of Class A surface

Draft analysis is performed over Class A surface and every surface is obtained as clearing.

All surfaces obtained are green in color, which means that the surfaces are clearing the draft analysis.

Creation Of Class B Surface

Now, Class B surface has to be created. For this surface should be offsetted for 2.5mm.
Publish class B surface.

Creation Of Class C Surface

Now class C surface has to be created and it is created from the boundaries obtained from the Class A surface. This boundary is provided as the input curve for sweep command. Using sweep command, class C surface is created.
Appropriate sweep is the provided considering the flash and considering manufacturing procedures. Surfaces are extrapolated if necessary.
Publish class C surface.

Creation Of Closed Surface

Now Class A surface and Class C surface is joined.

Now Class B surface is also trimmed with the obtained surface to get the closed surface.

Boundary check is done to check for any open boundaries in the part.

The closed surface then obtained moved to part design and close surface tool is used to obtain the part.

Creation Of Doghouse

Doghouse are created by following the design rules.
It is then made to closed body and is made to part model.
Shell operation is performed to get hollow structure and then coring is done in order to avoid sink marks in the class A surface.
Drafts are given for the surfaces as per design rules and proper fillets are also provided.
As per the given master section, ribs and supporting features are also added in the doghouse.
The doghouse is then rotated for the easy manufacturing.
Doghouse is also copied and translated to other points for attaching the pushpins and to stick with the sheet metal component.

Then, the doghouse is added to the main body.

Draft Analysis Of Plastic Component

The obtained part is draft analysed to check for the correctness of obtained model by following the draft analysis procedure mentioned above.

Side core has to be created for the doghouse to get ejected. So, a side core axis is also created for checking the draft analysis of the component.

As I had rotated the model while adding the doghouse to th main body, so I had done the draft analysis with the side core axis by deactivating the rotation in the part model.

Draft Analysis Of Plastic Component

The obtained part is draft analysed to check for the correctness of obtained model by following the draft analysis procedure mentioned above.

Screenshots Of The Solid Model With The Proper Color Code Of The Draft Angle In Various Orientations

Engineering features are also created in such a manner that it also clears the draft analysis.

Draft analysis at 1.5 degree for the clearance of doghouse:

Draft analysis at 0.5 degree for heatstakes and locators:

Parting line is created for the lower substrate. Parting line is the line which comes between the junction of joined class A and C surface with class B surface. It is the line that separates core and cavity.

APPLYING MATERIAL DETAILS TO THE COMPONENTS

Plastic material is applied to every component and its measurements are taken:

BOTTLE HOLDER

Mass: 0.343kg

UPPER MAP POCKET

Mass: 0.222kg

DOOR ARM REST

Mass: 0.182kg

LOWER SUBSTRATE

Mass: 0.631kg

FINAL PART

After applyinf material:

Total mass: 1.399kg

CONCLUSION

Created Tooling axis
Created Class B and Class C surface from provided Class A surface.
Created solid part out of surface modelling using master section for reference.
Created engineering features as per the design guidelines in the industry and with master section.
Draft analysis of Class A surface and final part is also done.

REMARK: I had done one on one session and has been reviewed by the Technical Support Engineer.

Week 11 - Final project

Ship work like this
in your own course.

Talk to a career counsellor

Ship work like thisin your own course.

Talk to a career counsellor

Ship work like this
in your own course.