Week 11 - Final project

Week 11 - Final project

Objective: To make a solid body of a side door trim of a vehicle from the given class As of 4 parts of the door trim which are Lower Substrate, Bottle Holder, Map Pocket, and Door Armrest. Also, B side features like doghouse, heat stake and locator should be added, all obeying the design rules and guidelines.

Theory:

Role of plastics in the Automotive industry

The automotive industry is the third most important consuming sector of polymers after packaging and building and construction.

The role of plastic in the design and manufacturing of automotive vehicles has never been more essential, with stringent regulations and changing consumer habits driving demand for more affordable, lightweight, and fuel-efficient vehicles. Fuel efficiency has become one of the most important features in automotive vehicle design due to the rising fuel prices and stricter environmental regulations.

There are about 30,000 parts in a vehicle, out of which 1/3 are made of plastic. In total, about 39 different types of basic plastics and polymers are used to make an automobile. More than 70% of the plastic used in automobiles comes from four polymers: polypropylene, polyurethane, polyamides and PVC. Plastic has become one of the key materials required for the structure, performance, and safety of automobiles in recent years, with growth in plastic consumption being driven by light-weighting trends for fuel efficiency and consequently lower greenhouse gas emissions.

Manufacturing Process:

Injection Moulding:

Injection moulding is one of the most commonly used production processes for plastics. It offers a viable solution for the mass production of high-quality injection automotive parts from a broad range of polymers. In the automotive industry, where consistency, safety, and quality are of utmost importance, automotive plastic injection moulding is an important manufacturing process.

Plastic injection moulding is the process of melting plastic pellets that once malleable enough, are injected at pressure into a mould cavity, which fills and solidifies to produce the final product.

From left to right, the components of a rapid injection moulding press include ram (1), screw (2), hopper (3), barrel (4), heaters (5), materials (6), nozzle (7), mould (8), and part (9).

Tooling Direction

Tooling direction is the direction the mould takes to make the part. It is basically the direction that the mould pulls apart. The mould is built in two separate pieces, a cavity side and the core side. The core pulls apart from the cavity and that is the Tooling Direction.

Core is the male part which forms the internal shape of the moulding. Cavity is the female part that forms the external shape of moulding.

Parting line is the line of separation on the plastic part where the two halves of the plastic injection mould meet, i.e. where the core and cavity meet.

Design for Manufacturing & Assembly (DFMA)

Design for Manufacturing and Assembly is an engineering methodology that focuses on reducing time-to-market and total production costs by prioritizing both the ease of manufacture for the product’s parts and the simplified assembly of those parts into the final product – all during the early design phases of the product lifecycle.

Before becoming the singular philosophy it's known as today, DFMA used to be considered as two distinct methodologies: Design for Manufacturing (DFM) and Design for Assembly (DFA).

DFM is concerned with selecting cost-effective raw materials and attempting to minimize the complexity of manufacturing operations during the product design phase in order to reduce the overall manufacturing time and costs for product components. Similarly, DFA is concerned with reducing the product's assembly time, costs, and complexities by minimizing the number of individual parts, assembly steps, and the potential for variability in build quality. 

Function of Heat Stake, Locator, Doghouse, and Ribs

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. 

  

Heat Stake (cylindrical structure on the left)             

A 2-way locating pin restricts motion along 1 axis (or 2 degrees of Freedom). Likewise, a 4-way pin restricts 4 degrees of freedom along 2 axes. 

Dog house is a 4 sided box attached to a flat surface which usually requires a riser/slider to mould. In other words, it has 3 sides and a roof, where the roof usually has a hole for attachment purposes.”

Ribs can be added to parts to add rigidity or stiffness. Adding ribs allows for a part to increase strength and bear a higher load.

Procedure: 

These are the given class A surfaces. These have been slightly modified from the original due to imperfections and instability in the original one.

DOOR ARM REST:

MAP POCKET:

LOWER SUBSTRATE:

BOTTLE HOLDER:

#HEAT STAKES

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

#RIBS

• The ribs provide economical stiffness and strength to the part without increasing the overall thickness of the part.
• The ribs are used as locating and arresting in the assembly as locators.
• Proper allignment in mating parts, slot and rib pair is long lasting other than screw pair which loosen up with time.
• Acting as stops or guide for mating the tilted headlamps.
• Rib designs includes.
• thickness, quantity, height , manufacturibility and location.

#DOG HOUSE

• Dog house is the attachment feature which helps you to assemble things at certain heights and also resolve the plastic defects.
• There are plenty dog house design which can be used for assembly purpose but we will  be using the one provided to ous by the resources.
• The master section or  the enginnering drawing must be followed for creating the dog house.

#PUSH PINS 

• These pins are used for  the assembly purpose .
• These pins are guided into the sheet metal body.
• The pin is assembled over the dog house on one side and other into sheet metal.

END OF REPORT...............