Week 12- Final project

DOOR TRIM

AIM

To create a Solid body of Side Door Plastic trim using the given Class A surface and master section and adding thickness to the component. Including the engineering feature such as Dog house, heat stakes, flanges, push pin using CATIA V5 software tool.

INPUTS

• CLASS A surfaces of the SIDE DOOR PLASTIC TRIM including door arm rest, map pocket, bottle holder and lower substrate.
• Master section for the attachment features.
• Push clips for the assembly.

OBJECTIVES

1. Analyzing the Class A and performing necessary modification to obtain the modified class A, checking if there is gap between the given Class A surface.
2. Creating the tooling axis for all the components by using method such as normal to surface method or bisecting lines method.
3. Performing draft analysis of Class A surface.
4. Creating the class B surface with the help of surface workbench.
5. Creating the class C surface with necessary draft.
6. Creating the Side core tooling axis for the dog house.
7. Trimming the CLASS, A, B AND C Surface for obtaining the final trim for all the components.
8. Creating the closed body for all the components using part workbench.
9. Creating the attachments on the LOWER SUBSTRATE for assembly like 4 WAY LOCATOR, HEAT STAKES, DOG HOUSE, AND FLANGES.
10. Creating the necessary flanges on the other components (if the heat stakes are designed on lower substrate, then creating flanges on the other component such as map pocket, bottle holder etc.) for the assembly purpose.
11. Performing the draft analysis and make sure all parts are clearing with positive draft.
12. Assembly of the push pins over the dog house in assembly workbench.
13. Attaching all the images of the door trim components.
14. Final submission of door plastic trim.

INTRODUCTION

DOOR TRIM

The door trims are the interior parts that contain the most controls and decorative parts. As such,power window control, orvm adjustment knob,speaker placing,  there is a necessity for balancing gap between parts, as well as an overall sense of unity between the numerous parts.

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

Plastics is the core and soul of the door trim interior, one must have knowlege about the plastic being used and its cost associated with the molding and manufacturing. Here are some plastic material used in door trim panel and explained below.

Types of Plastic used in Automotive Industry:

Plastic seems to be popping up everywhere nowadays, and the automotive industry is no exception. High performance plastics used in cars are helping shape the future of transportation while providing us the safety and security we need for our morning commutes today. We're going to introduce you to some of the plastics at the forefront of automotive design and innovation.

1. Polycarbonate (PC)

Polycarbonate is so resistant to impact that it is often used for car bumpers and headlight lenses. This kind of car plastic is highly resistant to weathering, able to handle conditions from rain and snow to heat and cold. Polycarbonate is also lightweight, so it reduces a car's overall weight, which in turn improves vehicle and fuel efficiency.

• High weathering resistance.
• High strength and Toughness upto 140degree celsius.
• very good heat resistance
• Good Dimensional Stability (Plastic products are being melted and poured in cavity, after cooling this manufactured product must not get deformed or shrink. It should maintain the Desired shape as we obtain from sheet metal Product Manufacturing.)
• Good electrical properties, stable over wide range of temp, frequency and humididty.
• Excellent Transpency often used in Headlamps, Instrument Clustor.

2. Polypropylene (PP)

Polypropylene is used the most frequently of any plastic in automotive manufacturing. Being a thermoplastic polymer, it can easily be formed into almost any shape. It has excellent chemical and heat resistance and is generally resistant to impact. Given this plastic's resume, you will frequently find it in car bumpers, gas cans and even the carpet fibers of your car's interior flooring. It's also a more economical alternative to expensive plastics of similar strength and durability, which helps drive down the cost of manufacturing.

3. Acrylonitrile butadiene styrene (ABS)

ABS sheet is similar to PVC in that the final product offers a sleek finish. Steering wheel covers and dashboards are often made of ABS plastic. It's also well-suited to heavy-duty applications, so it can be used for automotive body parts, too. Plastic used in cars, like ABS, helps the body absorb and redistribute energy during an impact, keeping passengers safe.

• High rigidity - Used in Door Trim, Instrument Panel.
• Good impact rsistance and hence used in Bumpers.
• Good Insulating Properties.
• Good Weldiability and hence Instrument Panel and Pillar trims are plastic welded.
• High dimensional stability (Mechanically Strong and stable over time)
• Excellent Surface finish.

4. Polyvinyl Chloride

Polyvinyl Chloride, more commonly known as PVC, is a flame-retardant plastic that can be formed into either flexible or rigid components. PVC is another common plastic used in cars thanks to its formability and sleek finish: you'll often see PVC used for dashboards and automotive body parts.

5. Polyamides (Nylons)

• Good Rigidity and hardness.
• Good Dynamic Fatigue Resistance.
• High Imapact strength, even at low tempeature.
• High Heat resistance.
• Excellent lectrical Properties.
• Good abrasion and wear resistance.
• Good sound and vibration damping.
• Used in Plastic Gears, Push Clips.

6. Poly Ethylene Terephthalate (PET)

• Ouststanding Chemical Resistance.
• Water repellent and used in Wiper Arms.
• Superior strength aand stiffness and used in Gear housing.
• Excellent dimensional stabiliy.
• Good imapact Strengt.
• High heat resistance and hence used in Engine cover.
• Flame Retardant.
• High gloss.

CLASS A SURFACE

When it comes to automotive injection molding, a Class-A surface is any high-quality plastic component that you see, touch, or engage with inside or outside of a vehicle. Aesthetics play a significant role in injection molded parts being classified as a “Class-A” surface.

Styling or A class surface are the terms used in plastic product design. That mean the surface of a component which is smooth (aesthetic) or visible side to human eye after the part is being assembled. we can also consider the outer surface of exterior (in automotive) as styling though it not plastic, but Bumpers, side mirror housing, lightening systems and fender in many cases are plastic (exterior trims).

The entire visible plastic surfaces you see inside the car (Dash board or instrument panel, door panels, etc.) are Class A surfaces even the visible surface of bumper, fender, mirror housing, etc. Smooth finish of a surface is high priority.

Examples of Class-A Surface Exterior Components:

Body Panels, Bumpers, Exterior Body Trim, Exterior Pillar Seals, Fender Stuffers, Grill, Lights.

Examples of Class-A Surface Interior Components:

Seat Components, Dashboard, Closure latch mechanism covers (Door, hood, trunk, liftgate, etc.), Closure stabilizer bumpers, Instrument panels, Center consoles.

CLASS B SURFACE

Class-B surfaces are the secondary surfaces that can be seen sometimes, such as the inside of your door trim, dash board etc. These must be smooth and error-free as well, but are not held to the standards that class-A surfaces are. Customer rarely sees the Class B surface as it’s an inside surface. Class B surface has attachment such as heat stakes, dog house, flanges to support another panel.

CLASS C SURFACE

The class C surface is the surface which is created to provide thickness to the class A surface with the help of class B surface. The class C surface is the middle portion of the class A and class B surfaces. The class C is created with the help of the sweep command in surface workbench.

The class A surface's boundary is taken as profile (guide curve) and then tooling axis created is taken as direction of the sweep in subtype draft direction. The draft angle for the sweep is 3 degrees.

HEAT STAKES

Heat Staking is a joining technology to join two or more parts together where at least one is made out of plastic. The process is used to melt and deform the plastic material using heat and force at a set process time.

De-forming the plastic is achieved by heating it above the glass transition temperature and apply pressure. After heating, the materials are cooled down under pressure again to below the glass transition temperature.

Heat Staking is a pulsed-heat process to join two or more parts out of which one at least is made of plastic. The process is to deform the plastic material using heat and force at a set process time. The bond is made by partially de-forming the plastic part in order to fix the other.

Heat Staking makes it easy to bond metal to plastic and is commonly used in high volume/low cost applications such as automotive, IT and consumer appliances.

The plastic is deformed by heating it to a temperature above the glass transition temperature. Super-heated air or a thermode is used for this. Pressure is then applied to create the stake. After the stake has been formed, the plastic should be cooled down again below the glass transition temperature. Cooling is performed under constant pressure to ensure good fixation of the parts. Compressed air can be applied for cooling when a thermode is used.

Heat is used to facilitate the creation of the stake. Heat control is critical, especially for glass-filled plastics which often have a process window of less than 10 degrees Celsius. When the temperature is too high, the glass fibers come out of the plastic which leads to a rough surface and adhesion to the thermode. If the temperature is too low, the plastic will crack due to cold deformation.

In the conventional production process natural fiber base material, such as door trims, were heated and pressed. It was then necessary to use an adhesive to attach the brackets and other resin components, which are produced in a different process, to the back side of base materials.

However, with the simultaneous back-injection molding technology the resin components are simultaneously injected as the base materials are heated and pressed, which allows the resin in the base material and the resin in the bracket to combine. This not only leads to a stronger adhesion, but also removes the need for a separate adhesion process

Compared to the traditional adhesive-using production method, this new process makes it possible to reduce the size of the resin components, allowing for increased production efficiency and reduced mass in the final product.

Why Use Heat Staking for Plastic Assembly Projects?

While multiple industrial processes for high quality plastic assembly exist, heat staking continues to earn a significant amount of market share for the sectors. While the industrial products of conventional joining technique were attached using hardware fasteners, this practice has become obsolete once heat staking technology became the industry standard.

Heat Staking eliminates the need for extra hardware, which can become defective, break, or otherwise suffer from quality control issues. Additionally, hardware fasteners tend to be more expensive and labor intensive than heat staking plastic fastening options.

Heat Staking Benefits:

• Local heating resulting in no damage to surrounding materials.
• Accurate control operating within a small process window.
• Processing of glass-filled materials.
• No mechanical vibration.
• Similar and dissimilar materials may be joined: metal to metal, plastic to plastic, metal to plastic.
• Many heat-stake shapes possible through custom designed tools.

LOCATORS

There are two classifications of locating pins, 2-way and 4-way. A simple method to remember the difference between them is to consider the 3 axes of translational motion, and the 6 corresponding directions or Degrees of Freedom. A 2-way locating pin restricts motion along 1 axis (or 2 degrees of Freedom), like a round pin in a slot. Likewise, a 4-way pin restricts 4 degrees of freedom along 2 axes.

DOG HOUSE

• Dog house is an engineering feature used in plastic trim design.
• Dog houses are used as supporting feature.
• Dog house are provided to avoid Sink Marks in the Plastic trim design.
• We cannot Design a screw boss which is longer in size. It might break if its longer, to overcome this situation we design dog house and over that we provide screw bosses which gives strength to the plastic product.
• Push Pins are attached over the dog house only.

PUSH PIN

• Push-pins provide easy manual assembly and quick mounting.
• Push Pins, also known as dart type fasteners, are versatile in design for a wide range of applications.
• They are well-suited for simplified assembly or products knocked down for worker assembly in automotive industry.

FEATURES & BENEFITS

Advantages of plastic Push Pins include resistance to corrosion, shock and vibration. In addition, Push Pins will

not work loose.

Here are some clips which are used in automotive industry for attachment purpose of metal-to-plastic component:

1. Snap clips

This snap-fit design assembles parts in just seconds without tools or screws. Once mounted, the fasteners are invisible, giving exposed panels a clean, finished appearance.

The fasteners are easy to service, making them ideal for interior trim, IPCC, and pillar applications.

2. Double-headed clips

Double-headed clips are used to adjust the distance between two panels and are available with a seal for water tightness.

3. Push-rivets

Push-rivets provide easy manual assembly and high serviceability without compromising retention. Simply push through or turn the screw to lock and the expansion leg provides a secure joint.

4. Edge panel clips

Multi-functional edge clips can be used to join metal-to-metal or metal-to-plastic panels or profiles. Manual mounting is fast and easy and requires no drilling, screwing, or welding. Integrated barbs provide a tight grip and a secure assembly. Upturned lead lips ease assembly over the panel edge. Different designs are available to suit virtually any assembly environment.

 Sequence of Operations to generate CAD Model of a Plastic component:

1. Extracting the input Class-A surface into different parts of Assembly.
2. Looking for defects in Class-A surface.
3. Improving Class-A surface by patching defects.
4. Improving Class-A surface as per Master section.
5. Using boundary command or join command checking whether there are some minute gaps in between the given panels.
6. Creating Tooling Axis for all the components of door trim.
7. Creating Class-B surface.
8. Creating Class-C surface.
9. Creating a Closed Body using part workbench.
10. Creating the heat stakes as per the given master section.
11. Creating Dog House as per OEM standard design Rules.
12. Creating Locator.
13. Adding Draft as per requirement.
14. Performing the Draft Analysis on the component.
15. Using Side core tooling axis for dog house clearance in draft analysis
16. Using Boolean operations such as ADD, REMOVE, UNION TRIM where ever it is required.

DESIGNING OF PLASTIC COMPONENT FOR GIVEN DOOR TRIM PANEL:

Door Trim Panel consists of following Components:

1. Door Arm-Rest.
2. Map Pocket.
3. Lower Substrate.
4. Bottle holder.
5. Push pin.
6. Heat stakes.
7. Dog Houses.
8. Flanges

01. DOOR ARM REST

DOOR ARM REST WITH 2 FLANGES FOR HEAT STAKES, 2 FLANGES FOR 4 WAY LOCATOR AND ONE ONLY FLANGE.

FORWAD FLANGE IS  FOR 4 WAY LOCATOR AND BEHIND FLANGE IS FOR HEAT STAKE

 

  

 

 

DRAFT ANALYSIS WITH MAIN TOOLING AXIS

DRAFT ANALYSIS WITH SIDE CORE TOOLING AXIS

 

02. MAP POCKET

MAP POCKET WITH TOTAL 3 FLANGES - UPPER TWO FOR HEAT STAKES, LOWER IS ONLY FLANGE.

    

TOOLING AXIS OF MAP POCKET

 

 

DRAFT ANALYSIS

 

03. LOWER SUBSTRATE

There are total 8 Heat stakes with two 4 way locator and two dog house.

Placing of Heat stakes -

• Two 4 way locators are place at the top curvature of lower substrate for better assembly purpose, locationg the heat stakes and proper assembly of all the components of Door trim panel.
• Two Heat stakes are  placed at the top of the lower substrate to attach with the Door arm rest component.
• Two Heat stakes are placed at the upper edge of map pocket so that the map pocket get attached with lower substrate.
• Four Heat stakes are placed in the curvature of the lower substrate the function of this four heat stakes are to get attached with the Bottle holder.
• One Dog house at the Left side of the lower substrate, middle dog house and another at the right side bottom of the lower substrate. (Idea behind placing this Dog house comes from seeing the door trim panel of my Maruti Suzuki Wagon R where it is attacted on the similar positioning for better attachment of full Door trim and aresting all the Degree of freedom and translation motion except motion in + Y axis and - Y axis translation motion.)
• Three push pin placed over the dog house so that the metal door gets attached/ assembled to the Plastic Door Trim Panel.

 

DRAFT ANLYSISIS OF LOWER SUBSTRATE

 

DRAFT ANALYSIS OF HEAT STAKES AND 4 WAY LOCATORS

 

DRAFT ANLYSIS OF DOG HOUSE WITH SIDE CORE TOOLING AXIS

 

DRAFT ANLYSIS OF DOG HOUSE WITH MAIN TOOLING AXIS

 

04. BOTTLE HOLDER

 

 

TOOLING AXIS OF BOOTLE HOLDER

 

DRFAT ANALYSIS

 

05. PUSH PIN

 

 

06. FLANGES

 

DOOR TRIM

 

 

 

 

 

 

 CONCLUSION

Thus we have successfully designed the Door Trim Panel with given Master section with all the necessary components and attachements such as heat stakes, dog house, flanges, push pin.