The first section of this guide will focus on the dissasembly of the robo shark and anylising the function of it's different compoents.

Later, this guide will look at the manufacturing methods and materials used in it's construction.

The first step in disassembling the shark is to take apart the outer shell.

Remove the battery compartment door to reveal a soft, clear silicone seal that waterproofs the compartment. The seal is wedged into a groove without adhesive and can be easily removed with tweezers.

The battery door contains two heavy metal plates to weight down the and help keep the shark upright in water. To disassemble further, remove the plastic plate. Carefully work around it with a utility knife, then slot a Flathead screwdriver in to pry it off. This plate is glued down so may not come off in one piece.

Under the shark's chin are two electrodes for water detection. Next to them are two small Phillips head screws (Red). Remove these screws, and the bottom half of the shark will come away, revealing the shark's internals.

for convenience, the sharks tail can be removed. This is done by gently squeezing the sides of the sharks tail (marked with red arrows) allowing it to pop off the retaining pins.

The sharks tail is flexible, allowing it to sway from side to side as the shark swims, creating a more realistic swimming effect.

The shark's belly is weighted, while its back contains a black blow-molded air tank that helps it float upright along the surface, exposing its dorsal fin in true Jaws style. To remove the bladder, cut or snap one of the retaining pegs (red) before sliding it out.

This is the most damaging stage of disassembly. Start by removing the two screws near the shark's tail. You'll then see several pegs molded into the upper shell (red). Spray these with isopropyl alcohol and let it sit and pool for 10-15 minuets.

Additionally, where the red upper jaw piece sits, the re are two pegs that slot into the two main halves of the upper shell. These should be sprayed with isopropyl to loosen them (marked with blue arrows)

Let all of the parts sit until the alcohol has evaporated, wipe away any residue with a paper towel.

Heat the joining pegs with a heat gun to help loosen them. Next, grab the shells and pry them apart, the glued joints should eventually pop apart.

To light up the sharks eyes, the light pipe connects to the led on the sharks brain box. this refracts light from the LED to the sharks eyes.

The shark's fins are secured with rings that fit over the pegs in the upper shell. Slip these rings off to remove the fins. The light pipe for the glowing eyes can also be removed with some force and isopropyl alcohol where it is glued in place (marked with blue)

Now for the interesting part: disassembling the shark's internals. Remove the five screws marked by blue arrows, securing the electronics case, gearbox, and propulsion system to the lower shell. Slide the pectoral fins off the hexagonal pegs on each side of the shell to remove them.

To swim like a shark, the shark uses an impeller (marked in red) to force water through a channel to the tips of the pectoral fins (marked in blue) propelling it forward. The motor also drives a gearbox that moves a gate (marked in green) back and forth, alternating the water flow between fins, causing side-to-side swimming motion.

The pectoral fins consist of two glue-bonded components, forming a channel for water from the impeller (blue) through their center, exiting at the tips (green) Pry them apart with a flathead screwdriver.

Gently pop open the electronics box by removing the last three screws (Red)

This reveals the LED that makes the shark's eyes glow (Pink), along with a capacitor (orange) and circuitry on the underside. The PCB has two solder pads that press against springs on the water-sensing electrodes (green). The box is in two halves, waterproofed by a silicone cover that also acts as a gasket, sealing the edges of the enclosure (Blue)

To disassemble the gearbox further, first remove the screws holding the motor cover in place (blue).

The motor cover can then be pulled off. It will provide some resistance as the wired connecting to the motor will come loose, snapping off (Red). These are held in place and waterproofed as they pass through the case with two dabs of silicone.

Additionally, this cover also retains the worm gears and axle that offer gear reduction in driving the gate (Blue). This worm gear and axle can be removed and set aside for safekeeping.

Use the tweezers to pry out and remove the silicone motor gasket that waterproofs the compartment.

Here, you can see the water channel gate driven by a cam-style system on a gear (blue). As the gear rotates, it moves a fork back and forth (Red), which in turn moves the gate.

There are two screws holding the top and bottom halves of the gearbox together (Blue) these can be removed and the halves of the gearbox separate.

The axle retaining the gate cam gear can then be removed from the gearbox shell.

The gearbox motor can then be removed from the shell. This requires the impeller and gearbox drive gear assembly to be pulled off the motor shaft. be careful not to loose the silicon O-ring (Blue) which provides water proofing around the motor shaft.

There is a final drive gear to be removed, concluding the disassembly of the upper gearbox shell. This component covered in grease, so be careful not to get any on your clothes.

This leaves one part to remove from the lower half of the shell: the gate assembly (Red) and cam follower fork (Blue).

Slide them off the axle. The lugs on these two components (blue) interlock, ensuring that when the follower fork moves, the gate moves as well.

That concludes the disassembly, now on to the materials and manufacturing methods analysis.

Attached is an annotated and labeled image of the sharks parts

All of the plastic components on the shark appear to be injection molded, asides from the air tank. The use of injection molding in these parts is evident as plastic injection points and mold ejector pin marks are evident (Red) (Hubs, n.d.)

Additionally, the geometry of the parts indicates that they are optimized for injection molding, with the parts features an open design that avoids undercuts or enclosed shapes, facilitating easy ejection from the injection molds (Hubs, n.d.).

The materials used in its construction are listed on the manufacturer’s website as Acrylonitrile butadiene styrene (ABS), polyvinyl chloride (PVC), and polyethylene (PE) (ZURU Toys, n.d.). The next step is to identify where each plastic is used.

The rigid shell of the robo shark, comprising both the lower and upper shell assemblies, is most likely made of ABS plastic.

This inexpensive yet durable plastic is commonly used in such applications (SpecialChem, n.d.). To verify this, a sample of the outer shell was cut, revealing a consistency and hardness similar to a known ABS sample.

In addition to the rigid shell, the robo shark features several soft, flexible parts, which are likely made of poly vinyl chloride or PVC.

PVC is widely used in a durable, flexible form (Material Properties, n.d.). To verify this, the soft components underwent a cut test, showing a hardness and consistency similar to the PVC sample piece.

Further testing of the suspected PVC components involved heating them with a heat gun. The parts became malleable quickly, a characteristic consistent with PVC (Material Properties, n.d.)

For the internal components, the gearbox housing and other plastic parts exhibit the same material properties as the external ABS parts, suggesting they are likely made from the same material.

However, the gears, impeller, and other internal components display different material characteristics. A key material identified in these parts is nylon, which is commonly used in prefabricated gears and motor components (Curbell Plastics, n.d.). , n.d.).

Testing revealed that these parts exhibit greater flexibility, bending more before breaking, unlike the ABS shell. This flexibility is a typical trait of nylon components (Curbell Plastics, n.d.)

The air tank that forms part of the sharks ballast system differs from the other components in material and manufacture method.

This component is manufactured with blow molding. This technique is cheaper than injection molding and allows the creation of water or air tight solid parts, making it ideal for this application (Alwepo, n.d.).

The air bladder shows a clear mold release line and uneven surface finish, both common traits of blow molding (Alwepo, n.d.). Additionally, the injection point for the part has been melted and sealed off.

From a material perspective, this part is likely made from polyethylene, as this is listed by the manufacturer as a material used in the sharks construction, and is commonly used in blow molding applications (Alwepo, n.d.).

There are also two rubber components in the shark, these being the battery door seal, the brain box seal and the motor gasket.

These appear to be made from silicone, due to their stretchy and slippery nature (Material Properties, n.d.). To test this, they are heated with a heat gun. Silicon will not deform as it is heat resistant, where other types of rubber may (Material Properties, n.d.).

As they did not deform, it is likely that these components are silicone.

In addition to the plastic components, the robo shark contains several metal parts including the gearbox axles, fasteners and the weights in the sharks belly. Although the manufacturer’s website states that these components are made of iron, their magnetic properties suggest they are more likely made from steel, coated in zinc.

This is determined from the bright, shiny finish on the parts, a strong indication that a zinc coating is present (Janekits, n.d.).

This coating is likely used to prevent rusting in the parts (A Class Metal Finishers, n.d.) as they are constantly exposed to water when the toy is in use.

These components are likely prefabricated, rather than manufactured specifically for the shark toy. Replacement screws for toys and electronics are commonly available made from zinc coated steel (Amazon, n.d.)

This concludes the materials analysis, a full bill of the materials including weights, materials, manufacturing methods and dimensions is attached at the end of this guide.