Project 2

Tail-light Lens A-Surface.

Closed body of Tail-lamp lens.

Tooling-direction of Lens.

Draft-analysis of the tail-lamp lens.

we kept minimum draft angle as 4.95deg for graining purpose.

Graining- It is the process of adding a pattern ,texture applied to the A-surface.

welding channel of Tail lamp lens for Hot plate welding is shown in the picture below.

Thickness of the lens welding track for Hot plate welding is 2mm

For Tail light Lens we use PMMA material and for Head light lens we use PC material because Tail light is mounted on the back side of the vehicle and head lamp is mounted on the front side of the vehicle so, when vehicle will be running on the road there is a chance that stones,mud,wind will impact on the lens so,when these things gets hit on to the head lamp lens there is a chance of skretching.In order to avoid this we go for hard caoating(Is a type of coating which is applied on the lens to protect the lens strength from these particles and sun light) on head lamp lens.PMMA material is not sutiable for Hard coating.

The above picture is the section view of lens with hot plate welding channel,as we can see in the picture there is an under-cut which can be clear by using slider.

Above diagram shows the slider line, slider will move along this line to clear the under-cut.

Above picture shows the Reflectors for Tail/stop,Turn-indicator and Reverse Function.

Refelctors are used to reflect the light and to produce strong parallel beam of light.In reflector the source of light is placed at the focus which after reflection forms parallel beam of light and material of the reflector we used is PC.

Above picture shows the Bulbs with Reflectors.

For Tail-stop -W21/5W,W21 is for stop function and 5W is for tail function.The colour of Tail/Stop bulb is Red.

For Turn-indicator-WY21,Y stands for yellow/Amber colour of the bulb.

And for Reverse-function-W16W,colour of reverse function bulb is white.

Flutes helps to hide the visibility of the welding area and also help us to get uniform output of the light and appearance wise also it looks good.

Above picture is the housing for the lens.used these sections to create the housing with hot plate plate welding channel,housing thickness is 2.5mm and housing material is ABS.

Hot-plate welding- It is laso known as heated tool welding,is a thermal welding technique used to join thermoplastics.In this welding process a heated tool is place near the two surfaces to be joined in order to melt them after melting heat source is removed and the surfaces are brought together by applying pressure.

For mounting reflector into housing we use M4X10 screws for fixing the screws we use bosses as we can see in the above picture.There are certain design rules to create boss.

Our reflector material is ABS.we create bosses by following the above design rules.

Our screw is M4X10 that is of 10mm length therefore we should keep atleast 12mm depth of the hole because our screw is self tapping screw and it will come from the housing side and it should have atleast 10mm interference and also self tapping screw has sharp thread beause of which it will cut the plastic part we keep 2mm more because plastic material will get deposit on that space.Moreover providing thread into plastic part is not possible it will create under-cut.

we create the section that shown in the above diagram on housing so that housing get fix with the reflector's bosses.This section also acts as a 4-way locator which makes easy for assembly.

For Tail/stop bulb colour is red but the red colour bulb is costly therefore we normally keep red lens and the portion which is covering reverse and turn-indicator we keep as white for which we go for insert molding.

Insert molding - Insert molding is a process in which plastic is injected into a mold that contains an pre-placed insert.The result of insert molding is a single molded plastic piece with an insert surrounded by the plastic.

When we are not able to make two different colour on a part in a single molding machine than we go for insert molding.For our tail lamp both the Red and clear lens will be mold separately and after molding we just slide the clear lens into the red lens we design both the lens in such a way that they will snap together.

Above picture shows the section of insert molding by following this section we can avoid spots on the lens that will create by the ejector pins also at the same time rib will hold the red lens.

Bulb will generate heat thats why we use high temperature resistance material for the reflectors,we also know that heat flows from high temp zone to low temp zone in order to maintain the flow we provide few holes on housing so that heat can flow out from that hole.

And if we keep that hole open than water and dust may go inside of the lamp and we will not be able to clean it so in order to avoid this we use vent caps.

There may be some kind of fog accumulation happens on the lens from the back side.Therfore the user will not be able to see the light properly and the same time he or she will not be able to clean the foggyness and it occurs due to temperature difference known as condensation to avoid this we provide hole on the reflector and housing.

vent caps -

• protect dust to go inside the lamp
• When heat comes out from the hole vent cap ensure that flow is maintained as per standard.

Section view of the vent cap.

For mounting the Tail lamp on the vehicle we use positive mounting , 2 stud pins and one clip. First we fix the clip on the BIW part and then we fix two stud pins after then we fix the lamp by suing M4 screws mount on the positive mounting.

We use 3-2-1 principle to assemble the part on the vehicle

Main principle of 3-2-1 principle is-

• Support
• Holding (clamping)
• Locating (positioning)

For tail lamp we clamp it by using clip fixed on clip-area,hold it by using 2 studs and support it by using positive mounting.

Main objective of 3-2-1 principle are-

• Accurately postion the part at the desire co-ordinates.
• Restrict all 6 DOFs so that the part can not move.

Due to design contrains we can not increase the height of B-surface features,if we increase the height of the features then we will see defects on the part,if the root thickness of the B-surface features is more than 40 to 60 percent of the part thickness then there will be sink marks.In order to avoid it we use Dog-house,Dog-house increase the height of B-surface feature.

As we can see in the above picture we provide coring on Dog-house,coring is a material removal process from the B-surface feature for minimum 3 to 5mm height in order to maintain 40 to 60% of the part thickness to avoid sink marks.

We also provide bosses to hold the Studs.

Above picture shows the boss with ribs,we kept rib thickness as 1.2mm that is 60% of the part(Housing) thickness to avoid sink mark.

Above picture shows the Postive-mounting area and the on the postive mouting area is for M5 screw.

We create seperate tooling direction and slider direction for dog-house because dog-house itself is having an external under-cut and we use slider to clear the external under-cut.

We fix grommet on back pannel its main purpose is to protect water to go inside the pannel and from pannel to inside lamp.Pannel thickness is 0.6mm.

Above picture shows the wiring harness for the Tail-Lamp.

Above pictures shows different views of Tail-Lamp.

Housing tooling direction,draft analysis and parting-line of hosuing is shown in the above pictures.

Parting line of Red lens and clear lens is shown in the above picture.

For Turn indicator we follow ECE-R48 and ECE-R6 regulations.As per regulation-

• Colour-Amber.
• Position in width-Max 400mm from the extreme outer edge of the vehicle.Min 600 mm between two indicators.
• Position in height-Min 350mm and Max 1500mm.
• Visibility-Horizontal 45 deg inwards to 80 deg outwards,Vertical inwards 15 deg and outwards 15 deg.

( HORIZONTAL 45 deg inwards and 80 deg out wards)

(VERTICAL 15 deg inwards and 15 deg outwards)

In our design max height of the turn indicatorn reflector is 968mm and min it is 905mm which is ok as per regulation.

For REVERSE FUNCTION we follow ECE-R48 and ECE-R23 regulations.As per regulations-

• Colour- white.
• Position in width- No regulations.
• Postion in height-Min 250mm,Max 1200mm.
• Visibility-Horizontal(inboard=45deg,outboard=45deg), Vertical(inboard=15deg,outboard=15deg)

REVERSE REFLECTOR Horizontal(inboard=45deg,outboard=80deg)

REVERSE REFLECTOR Vertical(inboard=15deg,outboard=15deg)

In our design max height of the reverse reflector is 965mm and min it is 904mm which is ok as per regulation.

For TAIL/STOP function we follow ECE-R48 and ECE-R7 regulations.As per regulation-

Colour-Amber.

Position in width-Max 400mm from the extreme outer edge of the vehicle.Min 600 mm between two tail lamps.

Position in height-Min 350mm and Max 1500mm.

Visibility-Horizontal 45 deg inwards to 80 deg outwards,Vertical inwards 15 deg and outwards 15 deg.

TURN INDICATOR REFLECTOR Horizontal(inboard=45deg ,outboard=80deg)

TAIL/STOP REFLECTOR Vertical(inboard=15deg,outboard=15deg)

In our design max height of tail stop reflector is 1055mm and min it is 993mm which is ok as per regulation.