Topics Covered
Introduction to Snowboards and Skis
History of Materials Used
Snowboard Materials
Ski Materials
Manufacturing Processes
Innovations and New Concepts
Negative Camber
No Camber
Edge Profiles
Beveled Edges
References
Introduction to Snowboards and Skis
Though icy winter conditions can cause treacherous road conditions, flight delays and numb extremities, many of us rejoice at the sight of snow as it marks the beginning of the winter sports season.
In recent years, skiing and snowboarding have becoming increasingly popular activities, with many individuals and families choosing to base an entire holiday around a location conducive to sliding down a hill a high speeds. In fact, with the emergence of dry and indoor ski slopes, skiing and snowboarding have become year-round activities, regardless of location.
The fundamentals are as follows: In snowboarding, the board is attached to the feet of the rider with a special boot set on a mounted binding. Snowboarding was inspired by surfing, sledding, skateboarding and skiing. Skiing is also quite similar to snowboarding, only that the skis are long rather than wide and you have the support of poles whilst traveling downhill skiing. In skiing, the feet of the user are in line with the direction in which the rider is traveling whereas in snowboarding, the user’s feet are almost transverse to the direction of movement.
As with any sport or activity, an increased interest has led to an increase in material innovation. This article gives an overview of materials used in skis and snowboards and points to how the sports may be shaped in the future.
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Improving the weekday commute... Snowboarding is becoming an ever more popular sport.
History of Materials Used
Snowboard Materials
The central structure of the snowboard is the core and it determines the characteristics of a snowboard. The cores are mostly made of laminated hardwood strips such as birch, beech, aspen, bamboo or a combination of some or all of these materials. Wood is used for the core as it helps in retaining the shape, enables good vibration damping and has less resonance when compared to plastic or foam. Other materials that can be used for the core include carbon, Kevlar, aluminium honeycomb and foam. Carbon is strong, light, high-strength, very good under compression, but this comes at a higher cost. Kevlar shows high strength, and is also a good dampener, good under tension and light-weight. Aluminium honeycomb is light-weight and strong, however is costly and does not have good damping capabilities. Foam is not used as the key material, as boards lose their camber easily and are not high-performing.
The fibreglass layers improve the stiffness of the board and ensure that the board does not deform. Resin is impregnated in the glassfibre sheets holding them together and rendering them strong. The topsheet is made of several materials such as wood, fibreglass, composites and plastics.
The snowboard base is made of a polyethylene plastic P-Tex. The base materials are usually followed by a number such as sintered 2000. The number is polyethylene’s molecular weight. A higher molecular weight indicates a stronger and more durable base. Graphite and other materials are also added to sintered bases making them stronger and faster. Graphite is conductive, hence as the snowboard slides, static charges are created between the snow and the base increasing friction. The static charges are dissipated by graphite, lowering the friction and increasing the speed of the base. Graphite bases are capable of holding more wax when compared to normal sintered bases, increasing their speed.
The edges of the snowboard are made of stainless steel or steel and are fixed using T-shaped inserts. Stainless steel inserts are in-built in the snowboard for the binding holes. The inserts are firmly attached to the core of the snowboard as all the force exerted by the rider on the snowboard will be transmitted through these inserts. The individual snowboard parts are held together with a resin. Wax is applied at the snowboard base so that less friction is created with the snow and its speed is increased.
Ski Materials
The central structure of the ski is the core and determines the longitudinal strength and the stiffness of the ski. Ski cores are normally made of fuma, fir, ash, paulownias, spruce, maple, bamboo or poplar normally with different wood strips laminated together. Wood has good vibration damping, retains shape and has a low resonance. In addition to the carbon, Kevlar, foam, aluminium honeycomb used to make the snowboard core, the ski core can also be made with fibreglass, air and titanium. Titanium is light-weight, high-strength and has good damping characteristics, but is costly. Air when used in the right proportion can bring down the ski core weight without any major impact on the core strength.
The ski sidewalls are normally made of ABS plastic often with rubber layers below to help in shock absorption and can have other material layers such as bamboo and aluminium. The torsional strength of the ski is rendered by the composite layers. These are mostly made of fibreglass; however, composite layers made of Kevlar, carbon fibre and titanium are also common. In most cases, a range of composite layers made of different materials are used.
The top sheet is made of a number of materials including wood, nylon, plastic, fibreglass and composites. The base material and the edge is the same as that of snowboards.
Manufacturing Processes
Torsion-box construction, laminated construction and single-shell construction are the ski manufacturing techniques commonly used. Various materials such as plastic and steel are compressed together forming laminated skis. In torsion-box manufacture, a soft inner core is wrapped with a hard outer material like fibreglass sheeting. In single-shell manufacture, a strong inner core is encased with a plastic or fibreglass mold.
Snowboards are made of fibreglass, plastic, steel and wood. The process normally followed for making a snowboard is listed below:
- The board top and base are made using the sublimation graphic application process ensuring colour brilliance and scratch resistance.
- Special dyes are used to print the artwork for the snowboard on a wide format printer and high heat is used to transfer the same to plastic sheets that constitute the bottom and top of the snowboard.
- After drying, the materials are made into shape and the snowboard’s steel edge is glued in place
- Triaxial fibreglass is cut to the required length and profiling and drilling of the wood core on a CNC machine is performed to ensure accuracy and precision.
- Other small components such as the tip and tail fill and rubber dampening material are cut to specification and materials are to be assembled for lay- up.
- A two part epoxy is mixed and the Ptex base material is kept in an aluminium cassette.
- It is essential that every shape and size of the snowboard has a corresponding cassette.
- On the PTex material, Epoxy is evenly followed by rubber dampening strips and a first layer of Triaxial fibreglass.
- The wood core is arranged and aligned after soaking. A second triaxial fibreglass layer is soaked with epoxy and the top sheet is arranged.
- After completion of the material lay-up, a top cassette is positioned with registration pins locking everything in place.
- The board is placed in a hydraulic or pneumatic press and the cassette is removed. The board is taken out and left to cool.
- The board is subjected 5 different grits of finishing belts, polishing the board, edges are finished, and after wax and polish the board is ready to ride.
Innovations and New Concepts
There are a number of new snowboard manufacturing concepts that are emerging and these are explained below:
Negative Camber
This is commonly known as a rocker. Here, the traditional camber is reversed so that when the board is placed on a flat surface the central section of the board is at a lower level than the ends that are formed upwards. In this way, it becomes more difficult to catch an edge as the natural tendency is to force the edges away from the snow making snowboards easy to spin around. However, due to this shape, the edge hold on harder snow is brought down significantly implying it is not suitable for free-ride boards. Freestyle specific snowboards have already been using the negative camber style and it is believed that it will impact other snowboards also.
No Camber
In this design, the board will be flat on a flat surface. In this shape, even though the edges touch the snow along their length, there will be no extra force to keep them there as in a traditional camber. The edge of this board is more than that of a rocker and less than that of a traditional board. This shape is now being used on powder orientated snowboards and on freestyle boards.
Edge Profiles
Innovative concepts that are aimed at producing better edge grip by focusing the edge pressure into few localized areas are slowly evolving. Several straight sections are used to make up an overall curve or the edge is given a wavy shape so that certain areas push into the snow more than the others. These innovations resulted from an attempt to uniformly distribute pressure along the edges.
Beveled Edges
In this design, detuning of the edges are done along the snowboard base so that the base is lower than the edges. The detuning of the edges is done by the same amount along the board but at times, the edges are detuned more in the board middle than at the tips.
References
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