Project 2
Aim:
To create the a complete design of the tail lamp with all the assembly parts and child parts, also the attachment features by considering the design regulations in CATIA V5 Modelling Software.
Objective:
- To the design the solid body tail lamp parts like lens and housing all other parts with the base thickness of 2.5mm.
- To determine the reflectors shape and posotio0nong in the housing.
- To use the standard parts of Bulbs, Screw boss and vent caps.
- To obtain the red and clear lens separately in the tail lamp design.
- To obtain the final assembly drafting of the tail lamp design.
Introduction:
Tail Lamp of Car
In the automotive the tail lamp is mounted in the rear part of the vehicle to let the other drivers know the approximate size and shape of the vehicle. It is the important safety factors for a vehicle. The color of the tail lamp is mostly red as it should be clearly visible to the other drivers. The lens and housing of the tail lamp are designed as per the industry standards by checking the all the regulations while designing the reflectors and making sure that there is no bleeding of light happening in the casing of the tail lamp design. Anti-fog condition is also been taken care of so that condensation does not occur inside the reflect region. The bulb which are used in the lighting industry are taken as inputs and placed at appropriate position in the reflection.
The General position of the tail lamp assembly in the vehicle as shown below,
Tail Lamp assembly and Positioning in the SUV Car
Methodology:
- Creation of the Len’s solid body:
The class A surface of the provided lens are not properly structured well, some patch work is done to obtain the fine class B surface. Some rework is done to the class A surface at the edges. It is offset to 2.5mm respectively to make the class B surface. Both surface is joined by using the Class C surface to have closed volume of the lens solid body as shown below,
The closed surface volume is then converted into the solid body as shown,
The tooling direction is created for the lens to determine the draft angle of the lens body which is to check the lens will clear all the direction in the draft analysis.
The lens body appears as full green body which means the it clear all the direction, which can be easily remove from the mold, as shown below,
- Creating the welding track to the lens:
Designing the welding track for the lens, by making the flange in the lens body and it is attached with it by making union trimmed with lens body as shown below,
Draft analysis is performed for lens welding body appears as full green body which means the it clear all the direction, which can be easily remove from the mold, as shown below,
- Creating the Reflectors for the lens:
The tail lamp as three reflector function namely,
- Tail stop Function
- Turn Function
- Reverse Function
The tail stop function will glow as red in colour when the vehicle stop or pause at motion of the vehicle, turn function will activated when the driver presses the induction direction and the reverse function will be activated when the vehicle will be moved in reversing the vehicle.
In order to design the reflector a parabola is first designed for the back side and the circular surface was made by taking the focal point as the center, both of them were split together to get desired shape and position of the reflector. Parameter and relations features was used to specify the diameter of the parabola so that in the future was used to modify the asper the requirement of the company.
Once the reflector is ready, now we place the bulbs to the midpoint of the reflector using the focal point meets in the reflector. The bulbs are standard parts in the industry so it is imported into the work place and then it is positioned using the focal point using the axis translation. Each functions the bulb color differs as mentioned below,
- Tail\Stop Function – W21/5W Bulb
- Turn Function – W21W Bulb
- Reverse Function – W16W BULB
Along the bulb the holder and seating area of the bulbs also imported in o the workspace as it is also the standard parts it is attached with the reflector by union trimming at the focal point position of the bulb and reflector by positioning using the axis transformation. As per industry certain rules are followed which specifies what should be the minimum and maximum distance which each function should be placed by considering all these function the reflectors were be placed. By considering the industry aspects the positioning as done by following the industry standards.
The parabola were designed with radius of 75 mm for tail/stop reflector, 45 mm for turn and reverse reflector as these are the standards followed in the industry. The circumference of each reflectors are made with same radius of approximately 40mm as the minimum distance that should be maintained above the focal point should be above 30mm and the below the focal point should be 20mm. along the sides the minimum distance should be 20mm.
Once the reflector surface created into closed volume it turned into solid body, the bulbs are placed respectively to the functions using the focal point as shown below.
- Creating the lens housing:
In order to create the housing for the lens we have to create the master section for the reference purpose. Master section is created using the help of surroundings, welding track of housing the lens body. The lens welding housing is done by using the HOT PLATE welding technique was to attach the housing and the lens body to accommodate this both lens and lens housing held at same meeting point.
To create the housing many industry factors are taken into consideration to make sure that there is no light bleeding happening inside the lens.
Horizontal Master Section of lens and Housing:
Vertical Master Section of lens and Housing:
In housing designing the surrounding wall is maintained at 12- 15mm distance so that hot pate welding operation can be performed successfully, without any defect in the housing. The above images shows the 15mm distance maintained between the lens and surrounding, but middle point is around 5-6 mm part is maintained , this is due to the avoid the phenomenon of light bleeding.
Light bleeding: when there are ore then one reflector in the housing than the lens it should be designed in a way in which light bleeding should not be occur. Bleeding of light happens when one color of light intersects with another color of light placed in the same housing. If this happens clear color of light won’t be visible and thus lighting will not provide desired output.
- Crating the attachment features to the housing:
To fix the reflectors to the housing, the screw boss were designed I the separate part called mounting parts and them after designing they were placed at appropriate position and then union trimmed with housing. The intersection view shows the mounting designed and assembled with the reflectors is shown below,
To assemble the lens with housing, it require the screw in bosses, here we take M4 screw as industry standard.
It is placed on the dog houses so that there are no sink marks or defect on the solid body during molding process. On the top of the screw boss in the dog house the studs were placed to fix it with BIW attachment of the vehicle, as shown below
Designing of dog house is considered that it should be clear along the lifter tooling direction so they can be tooled easily along this direction. The below image shows the lifter direction for the dog house.
- Creating vents caps and hole:
One of the primary thing we have to consider while designing the lens is to avoid the condensation. Condensation occurs to the bulb due to when there is temperature difference between the surrounding then the lens will become unclear from inside due to drop lets will formed. To prevent from this situation vent areas are developed in the reflectors so the heat generated can be easily comb out from the back side of the reflector and the temperature does not become high at those regions
The positioning of vents are also taken into consideration, which depends on these factors
- It should not be visible to the customer.
- It should be easy for them to perform their function.
- It should not obstruct the flow of light or the light reflection.
- Creation of Ribs
Ribs used as support element for the screw boss, it is also designed by using the required position to add strength to the different mountings and reflectors are present on the housing. Positive mountings, vent areas along with vent caps and ribs are shown below,
- Creation of Parting lines:
Parting line is an inevitable defect for the plastic injection molded part. It happened on the surface where the moving halve and the fixed halve meets and formed an edge like circle around the surface. When the mold is closed and the molten plastic gradually fills the cavity, high pressure inside the mold will push the molten flow occupy every space in the mold core and leave the circular mark around the parting surface.
Here the parting line is created for the housing part, as shown below highlighted line,
- Creating of Wiring Harness:
A cable harness, also known as a wire harness, wiring harness, cable assembly, wiring assembly or wiring loom, is an assembly of electrical cables or wires which transmit signals or electrical power. The cables are bound together by a durable material such as rubber, vinyl, electrical tape, conduit, a weave of extruded string, or a combination thereof.
Every vehicle provides the one wire each for 1 Tai; Function, 1ground Function, 1 turn Function, 1 stop Function, 1 Turn Function, 1 Reverse Function. In our project we are going to provide with 4 pole connector which provides all these wires coming out with it.
Color of wire for each function:
- Tail stop Function – 1 Brown wire for Tail Function \ 1 red wire for Sop Function.
- Turn Function – 1 Orange wire for Turn Function, 1 Black wire for Ground
- Reverse Function – 1 White for Reverse Function and 1 Black wire for Ground
A grommet is designed at the back side of the housing which functions as a connector between the pole connector and the wires coming out from the housing. At the grommet addition wire can also fixed to give more function to the lamp.
- Creating of final lens (Red and Clear lens):
In order to incorporate all three function n he tail lamp design, a clear lamp is also designed along with red lens. It is done by using the insert molding technique will be used so all the function ca be clearly visible and perform their functions accurately.
Insert Molding Specification:
Parting Lines of the lens is made which will be used as the reference to separate the core and cavity while molding the lens. The below images shows the parting lines of the lens. The red and clear lens parting lines are highlighted in dotted line’s as shown below,
- Creating the Flutes in the Reflectors:
The lights spreads in all direction inside the reflectors, in order to project most of his light rays outside flutes are designed on each side surfaces of the reflectors so that all the light can be emitted in the outwards direction.
- Drafting of Assembly and Child parts of Tail Lamp:
Dimensions and regulations for each part is shown detail manner using drafting as shown below,
Here initially we are going to see the assembly drawing of the tail lam design,
Front View of the Lens Body Assembly
Side View of the Lens and Housing Assembly
Rear View of the Lens and Housing Assembly
Vertical Section showing the Lens Assembly
Horizontal Section of Lens Assembly
Detailed view of Screw Boss and Hot plate welding
Detailed view of Attachment Features in the Housing
The Child Part drawing as showing number of parts included in the tail lamp design,
- Lens:
Front View of the Lens Body
Side View of the Lens Body
Rear View of the Lens Body
- Housing:
Front View of the Lens Housing
Side View of Lens Housing
Rear View of the Lens
Vertical Section of Lens Body
Horizontal Section of Lens Body
Detailed View of Insert Moulding
Vertical Section of the Lens Housing
Horizontal Section of the Lens Housing
- Reflector:
Frontal View of the Reflectors
Horizontal Section of Reflectors
Vertical Section of the Reflector’s
- Bill of Material:
A bill of material or product structure is a list of the raw material, sub-assemblies, intermediate assembly, sub components, parts and its quantity of each needed to manufacture end product
The below table represents the BOM of the Assembly drawing of Tail Lamp Design.
The below table represents the BOM of the Child Part drawing of Tail Lamp Design.
- Tree Structure:
- Screen Shots of the Tail lamp Design:
Isometric View of Tail Lamp
Front View of Tail Lamp Design
Rear View of Tail Lamp Design
Side View of Tail Lamp Design
Conclusion:
The complete tail lamp design of lens and housing assembly by successfully made by following the industry standards.
- The solid lens and housing was made which can be attached together with Hot Plate welding.
- Attachment features like mounting and screw bosses were designed at the rear side of the housing to attach the housing the reflector to the housing.
- Draft analysis was performed on each stage to cross check if the parts made can be easily machined by using the required draft applied to each component.
- Drafting of the lens and housing assembly was achieved to represent the specification of each part.
- Bill of material was also presented to know all the information of the tail lamp design.