How are disc golf discs made?
What is a disc golf
Disc golf is a rapidly growing sport that combines elements of accuracy and distance, similar to football, played with a flying disc or frisbee. The sport has seen significant growth in recent years, with the number of courses in the United States alone increasing by 10% each year for the past three years. This growth is expected to continue as more people become aware of the benefits and enjoyment that disc golf offers.
Disc golf has its roots in the broader history of frisbees, which date back to the Frisbie Pie Company of New Haven, Connecticut. The term “frisbee” became synonymous with flying disc play, and in the 1950s, the first mass-produced flying disc, the Pluto Platter, was created. The Professional Disc Golf Association (PDGA) was formed in the 1970s to promote the sport, and today it has over 14,000 members in 20 countries playing on over 700 frisbee golf courses.
Disc golf is played by throwing a frisbee from a tee area toward a target, which is usually a metal basket. The object of the game is to complete the course in the fewest number of throws. The sport requires both accuracy and power, as players must navigate through various terrains and obstacles to reach the target in the least number of attempts.
The popularity of disc golf is on the rise, with 40,000 athletes in 35 countries competing in the sport. The World Flying Disc Federation (WFDF), established in 1984, oversees organized competitions in nine different events, including disc golf and freestyle, with member associations in 22 countries and provisional members in an additional 28 countries.
Disc golf is not only a recreational activity but also a sport with potential for Olympic recognition. For a sport to be eligible for the Olympics, it must be played in at least 50 countries for two years. Ultimate Frisbee, a related sport, is already played in 35 countries, and its popularity, along with other frisbee sports, is growing.
Materials Utilized in the Production of Disc Golf Discs
In the contemporary era of disc golf, the manufacturing of discs has evolved to primarily utilize a specific plastic known as polypropene.
Polypropene, classified as a thermoplastic resin, possesses the unique ability to melt when heated and solidify upon cooling. This characteristic renders it an ideal material for the disc golf disc manufacturing process, as it can be easily molded into a variety of shapes and forms.
Beyond polypropene, manufacturers also incorporate other materials such as polyethylene resin, thermoplastic elastomer (TPE), and polyurethane plastics in the creation of disc golf discs. While some manufacturers might experiment with alternative materials, thermoplastic resins dominate the industry due to the numerous advantages they provide.
One significant advantage of thermoplastic resins is their capacity for reshaping, coupled with their stability and resistance to high impacts. Additionally, thermoplastic resins are considered environmentally friendly for disc production. They are recyclable, eliminating the emission of harmful odors and toxic fumes throughout the manufacturing process.
The Process of Disc Golf Disc Production
Disc golf discs are manufactured using a rapid and efficient method known as injection molding. This technique involves the injection of molten plastic into a closed mold, which is often designed with multiple cavities. Within the mold, the plastic cools and hardens, taking on the form of the cavity’s shape.
The injection molding process is capable of producing intricately shaped discs, necessitating only minimal trimming once the discs are removed from the mold. This method is not only efficient but also versatile, as it is used to produce a broad spectrum of items, including toys and automotive components.
The machinery used for injection molding is equipped with several key components: a hopper for feeding raw materials, a heated extruder barrel to melt the plastic, a reciprocating screw to move the melted plastic forward, a nozzle to inject the plastic into the mold, and a mold clamp to secure the mold in place. The machine heats the plastic to a temperature that allows it to flow under pressure, injects the molten material into the closed mold, maintains pressure during the injection and solidification phases, and finally opens the mold to facilitate the removal of the finished disc golf disc.
Preparation of Raw Materials for Disc Golf Disc Production
- The initial stage involves a compounding operation that transforms resin into a form suitable for injection molding, often incorporating additives. For thermoplastics, this process typically results in the creation of dry, free-flowing pellets through extrusion and drying, which occurs at the plastic manufacturer’s facility. Post-compounding, the material undergoes checks for moisture levels and molecular weight.
- The resulting plastic pellets are transported to the disc golf disc manufacturer in bulk, either in bags weighing 50-100 lb (22.7-45.4 kg) or in larger boxes of 500-1,000 lb (227-454 kg). These pellets are introduced into a large drum, where pigments and additional weight-enhancing additives are mixed in. A bonding agent, such as oil, is used to ensure the pigment adheres to the pellets, and the drum is vibrated to ensure thorough blending.
Feeding the Material into the Molding Machine
- The unmelted pellets are loaded into a hopper, which feeds them into the barrel. The hopper may include a drying system to eliminate excess moisture and a magnet to remove any metallic contaminants. In some cases, the compounding process is partially or fully completed during this step.
Transporting and Melting the Material
- The molding compound is transported from the feed section into a heated extruder barrel containing a reciprocating screw. As the material moves down the barrel, it is gradually melted. The tapered screw facilitates pumping, compression, decompression, and mixing, creating a pressure gradient that degasses the material through vents in the screw. Thermoplastic materials necessitate longer screws with compression ratios ranging from two to three or higher.
- Towards the end of the transport process, a predetermined volume of compound, known as a shot, accumulates in front of the screw. When the screw’s travel is reversed, this shot is forced forward. To prevent backflow during injection, a mechanical valve is installed at the screw’s tip.
Injection into the Mold
- Once sufficient material has accumulated for mold filling, the screw rotation halts, and the machine prepares for injection. The molten plastic is injected into the mold through a nozzle, under high pressure (typically between 10,000-30,000 psi), using a system of runners leading to the mold’s gate. Multiple gates are often used for material delivery, with each gate fed by a channel or runner. Proper injection also requires adequate venting of air within the mold.
Cooling and Removal of the Molded Disc
- To expedite solidification, the mold is equipped with a cooling system, often involving holes through which a cooling fluid like water can circulate. Once the disc solidifies, the mold clamp, which keeps the mold halves closed against the injection pressure, opens to allow retractable arms to extract the disc. Concurrently, the screw begins rotating to melt material for the subsequent shot.
Decorating the Disc Golf Disc
- Post-molding, the disc golf disc is decorated with imprints or designs that include the disc’s name, manufacturer, and other relevant information. Hot stamping is the most common method, but other techniques include silk screening and letterpress printing, with the latter using a separate ink pad for each color.
Packaging the Disc Golf Discs
- After decoration, the disc golf discs are prepared for packaging. One common method is to place each disc into a plastic bag and attach a cardboard header with staples. Alternatively, the discs can be placed on a cardboard backing and shrink-wrapped with plastic film. In some cases, the discs are packaged in boxes.
Ensuring Quality in Disc Golf Disc Production
Weight and flexibility are critical quality metrics in the production of disc golf discs. The weight of each disc is meticulously managed through the injection molding process, where the machine’s screw mechanism ensures that the correct amount of material is injected into the mold, thereby controlling the weight automatically.
Flexibility is another key attribute for disc golf discs, and it is assessed by placing a weight on the disc’s edge and measuring the degree of curvature it experiences. This test provides insights into the disc’s structural integrity and play performance. According to the Professional Disc Golf Association (PDGA), it is sufficient to test a single sample of a new golf disc design for flexibility to ensure consistency and quality across the production run. This selective testing helps maintain high standards while optimizing the manufacturing process for efficiency.
Distinctions Between Disc Golf Discs and Frisbees
While the sports of disc golf and frisbee are inherently connected, there is a common misconception among some enthusiasts that the discs used in these sports are identical. In reality, there are significant differences between a disc golf disc and a frisbee, both in terms of their physical attributes and their flight dynamics.
The production of disc golf discs, which are engineered for long flights and precision, involves a more sophisticated manufacturing process compared to that of frisbees. Disc golf disc manufacturers must first identify the specific type of disc they are producing, such as putters for short shots, midranges for medium-range throws, or distance drivers for long distances. Each type of disc golf disc has unique requirements that must be met to satisfy the needs of players. Consequently, the manufacturing of disc golf discs is a more complex undertaking than the production of the frisbees typically found in recreational settings.
