Analysis

Table of Contents

1.1

Our product, the Bike Light, attaches to a bike seat and provides illumination from the rear. This increases riders' visibility and thus safety.

1.2

Circuit Board and Bottom Shell (side)

This circuit board has two soldered legs connected via positive and negative metal leads down into the battery bay. The circuit board is slid into two plastic holders which constrain the board.

Circuit Board and Bottom Shell (top)

There are two buttons, five LEDs, and two bottom laser lights soldered to the circuit board. Additionally, two screw holes in the board for use during fabrication.

Circuit Board and Bottom Shell (partially removed)

The bottom laser lights have threads. These are to enable the light to screw into the incline.

Light Shield

The light shield screw holes are useless because the part is clamped by both the top and bottom shell.

Top Shell

There are two threaded holes for screws deep in the plastic rods and at the top cover there are two holes for buttons. This simply is the top cover of the whole light.

Screw

Two screws are used to hold the top shell, bottom shell, and the light shield secure in their ideal positions.

Battery Bay

The battery bay is designed for two AAA batteries. It has two slots at the sides which hold the metal terminals that slide and fit into the slots.

Battery Cover

The battery shell can slide in or out for battery replacement.

Battery

Two size AAA batteries are used to power this light.

1.3

All together, the product consists of 17 parts. This isn't too surprising, several to hold it together and several for the electronics is about what's to be expected. The only ambiguity encountered about what counts as a part and what a sub-assembly was regarding the electronics. We ending up counting all of the wiring as one part, and each of the LEDs and lasers individual parts.

1.4

The only product-specific parts of the bike light are the top shell, bottom shell, battery shell, light shield, and circuit board. The other parts--the battery, the LEDs, the buttons, and the wiring--are all standard components that could be purchased from a hardware store.

1.5

Looking at the top shell and light shield, it is hard to tell exactly which materials they are made of. As described later in section 1.6, they are injection molded parts which narrows down the options. The top shield seems likely to be made from high impact polystyrene (HIPS). This is because it looks very visually similar to other products made from HIPS and also because the needs of this part of the product are met better by the properties of HIPS than most other plastics. The light shield is likely made from acrylic. Similar red light coverings are made from this material as well. The circuit board is made from fiber glass and copper, as with most circuit boards.

1.6

1.7


The injection molded parts of the bike light use several techniques to reduce manufacturing costs while still retaining the required structural strength for the parts. The walls of the injection molded parts appear to have a uniform thickness to ensure uniform cooling times throughout the part which reduces cycle times. There is also structural ribbing on the parts to allow for thinner walls while still maintaining rigidity in the parts which will reduce both material cost and cycle times for the parts. The interior of the injection molded parts appear to have a rougher surface finish than the exterior of parts in order to reduce costs in areas of the part where appearance does not matter.