Week 11 - Final project

DEVELOPMENT OF DOOR TRIM PANEL

INTRODUCTION:          

Door panels serve as an interface between the interior of the car and the inner workings of the door, and between vehicle occupants and the door. They are expected to meet a variety of design specifications regarding safety, aesthetics, and functionality. In addition, they are expected to continue the material theme of the dashboard and pillars while concealing intricate electrical and mechanical components for operating locks, windows, and other features. The door panel has evolved from a simple two-part system of latch and simple winding mechanism to a more sophisticated enclosure. Doors currently have an inner full-width panel consisting of electronic windows, central locking system, and speakers. These panels typically consist of a foamed core covered with either textiles or plastics.

In this project, an inner car door panel is given with class A surface, to create the door trim panel it is divided into sub-parts namely, a lower substrate, inner map pocket, outer map pocket, and door armrest.

INPUT:

Sectionalization:

                           Dividing the given surface into 4 parts to prepare each part individually for manufacturing and then assembling. The parts are created according to the master section given along with input. Top pictures I mention the different colour.

The different components given are

• ARMREST (Class A surface):

• LOWER SUBSTRATE (Class A surface):

• BOTTLE HOLDER (Class A surface):

• MAP POCKET (Class A surface):

1. DOOR ARMREST:

                  TOOLING AXIS:

                               Create a point on the class A surface to move the main tool for component creation on the base surface. Mask an axis over the point created with the same directions as the main axis. Using Intersect command from Generative Shape design select the YZ plane as the first element and the class A surface as the second element After creating the intersecting lines select the Line command and join the vertices which show the most possible draft angle manufacturable.

 Create a point on the class A surface to move the main tool for component creation on the base surface. Mask an axis over the point created with the same directions as the main axis. Using Intersect command from Generative Shape design select the YZ plane as the first element and the class A surface as the second element. After creating the intersecting lines select the Line command and join the vertices which show the most possible draft angle manufacturable.

Draft analysis (class A surface):

                   After Tooling Axis Select the Feature Draft Analysis option from the Insert Option. Next click on Use the compass to define the new current draft direction option and make it align with the tooling axis by dragging it to the axis. If the colour appears blue just click the invert option on the right side of the draft direction axis button.

 Class B surface:

                     Using the Offset command and taking reference from the master section provided an offset of 2.5mm is given for the thickness of the part. Since fillets were creating problems for surface creation so by using the multi-section surface command the remaining surfaces were created.

Class C surface:

                     Here all the outer boundaries are extracted according to the requirements. Using sweep command with the draft direction of (2-3) degrees we get the Class C surface. The sweep was created in patches as connectivity error was occurring each sweep was extrapolated and trimmed together to create one single class C surface.

Class A+C surface:

Close surface:

               Final surface model was created by joining class-A and class-C surfaces together and later trimming them with class-B surface.

Solid part:

       Once we get the surface model, we make it into solid model by going to part design and closing the surface. Once that is done, we run a draft analysis on the component and once it is clear, we move ahead with making B-side features and again run a draft analysis on the entire component. Below image shows the analysis on lower substrate component after making all the features. Overall completed model on armrest.

Draft analysis:

                     Our first step before starting the model should always be to check is the surface has enough draft that it will not create any problems while ejecting from the mould. This seems like a big task as we have to foresee something that will come at very later stage. But this is done by a small process called draft analysis. This analysis tells us whether our component will be safely ejected in the tooling axis we have provided. Some components require side core where there are under undercuts, holes or projections on the side walls, so for this we need a different tooling axis and a different analysis is required to check those areas. Draft analysis shows colour codes which are defined by the user for different values which also are defined by the user. These colours help us to analysis if the component is clearing the analysis and we are good to go ahead or not. In case the component fails the analysis for class-A then we have to submit the draft analysis report to the higher authority so that the surface of the component can be improved. Failing analysis simply means that the component does not have the required draft value it must have. In case our solid model which we develop, fails the analysis at some parts then we have to correct it ourselves. We have to make sure that our entire model is green which means it is clearing the analysis. So, we have to run analysis for class-A, solid model and other B-side features as every single component, regardless of its size should be ejected safely from the core.

2. LOWER SUBSTRATE:

      TOOLING AXIS:

Draft analysis (class A surface):

Class B surface:

Class C surface:

Class A+C surface:

Close surface:

Solid part:

Draft analysis:

3. BOTTLE HOLDER:

      TOOLING AXIS:

Draft analysis (class A surface):

Class B surface:

Class C surface:

Close surface:

Solid part:

Draft analysis:

4. MAP POCKET:

          TOOLING AXIS:

Draft analysis (class A surface):

Class B surface:

Class C surface:

Close surface:

Solid part:

Draft analysis:

Ribs:

          Ribs are thin wall-like structures that add support and rigidity to injection moulded 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.

1.Rib thickness should be 50 - 75% of the wall thickness.

2.Fillet radius should be 40 - 60% of the rib thickness.

3.Rib root thickness should not be more than 25% greater than the wall thickness.

4.Rib depth should not be more than 5 times the rib thickness.

5.Taper ribs for mould release.

Dog House:

           Dog house is an engineering feature used in plastic trim design. These are used as supporting feature and other engineering features such as bosses, locators etc are mounted on them to increase their strength. Dog houses require a slider for moulding and are subjected to draft analysis along the slider axis to prevent breakage during ejection from mould cavity.

Heat Staking using heat stakes:

              Heat staking technology is quite simple in concept. Whenever two or more components need to be attached to one another, and at least one is made of a thermoplastic, a combination of heat and pressure can be used to reform the plastic to the many shapes or profiles to retain or join the parts together.

                This creates a solid, hardware-free bond that uses the plastic’s inherent strength to keep the finished assembly together.

4 ways:

           4-way locators restrict 4 degrees of freedom along 2 axes of an object

Draft:

            Plastic heavily relies on mould draft in the course of its removal from the mould. Due to which plastic parts are to be designed with a taper (or, draft) in the direction in which the mould moves. In such case, the lack of an appropriate draft would make the removal of plastic parts almost impossible.

Radius:

             The radius should always be with regards to the part thickness thereby eliminating the prospects of high-stress concentration and resulting in the breakage of the plastic part. General guideline suggests that the thickness at the corner should be in the range of 0.9 times the nominal thickness to 1.2 times the nominal thickness of the part.

Push-pin:

       This Push pin assembles on the doghouse.

Flange:

              A flange is an area, typically perpendicular to the mould cavity edge, that either mates to another part of the mould or acts as a stiffener at the cavity edge, or provides valuable processing area for closed moulding processes.

FINAL OUTPUT: