Abrasive waterjet cutting is widely used in industrial applications all over the world. In this JetTalk trilogy series, we explore why waterjet cutting and garnet are a match made in heaven. Furthermore, we also discuss why GMA Garnet can help give your waterjet cutting operations the edge over the competition.
1. What is waterjet cutting and how does it work?
Abrasive waterjet cutting is a (non-thermal) cold cutting process operated by a waterjet machine. Using only natural abrasive and water to cut almost any material, this process gives a smooth cutting surface with no slag or heat affected zones.
An ultrahigh-pressure pump generates a stream of water with pressure rated between 4000 – 6000 bar. This pressure is converted into speed. High pressure water (generally 3.8 litre per minute) flows through an orifice with a diameter between 0.10 – 0.33 mm (made from ruby, sapphire, diamond or tetraCORE™) into the cutting head, creating a stream up to 1.000 m/s.
Garnet particles are fed into the focusing tube (made from tungsten-carbide) via an abrasive inlet, then introduced into the water stream to produce the necessary cutting force to cut materials up to 100mm thickness with a tolerance of ± 0.1mm.
Waterjet cutting equipment offers incredible flexibility that can be easily adjusted for specific cutting requirement.
2. Why is garnet used as an abrasive in waterjet cutting instead of other substitutes?
Over the last 30 years, both natural and synthetic abrasives have been considered for use in waterjet cutting. Almandine garnet has been identified as the most suitable mineral for waterjet cutting due to its unique characteristics, high performance and overall profitability of the operation.
Abrasives softer than garnet, such as olivine or glass, provide long mixing tube life but do not ensure fast cutting speed. Abrasives harder than garnet, such as Aluminium Oxide or Silicon Carbide cut faster than garnet but do not provide a high cutting-edge quality and shortens the lifespan of the mixing tube by up to 90% in comparison to garnet.
In addition, garnet is also environmentally friendly as its waste can normally be landfilled or used as a filler in asphalt, concrete products, and could be recycled up to 5-10 times. GMA Garnet™ is the recognised industry standard among manufacturers of waterjet cutting machinery. It is precisely engineered to support both peak performance and longer lasting operating life for today’s highly sensitive waterjet cutting tools.
“Best cutting quality, we use less (5-20%) garnet to receive this result.” - GMA ClassicCut 80, Metal Service Centre, Waterjet Stainless Steel Cutting.
More waterjet tips and insights will be revealed in our next JetTalk article.
By Kjeld Lauritzen