Buying a Water Jet Machine? Precision Machine means Precision Parts

There are many companies that manufacture water jet machines or components. When purchasing a water jet cutting machine, be sure to look good at the x-y positioning precision of the manufacturer of the machine. The more accurate the hardware capability, the more accurate the parts you are able to quote, and thus cut. The physical positioning of the hardware, both while moving and while at rest is an important aspect of the final tolerance of a part, but it is not the whole story. Just be aware that some of the other aspects that affect part tolerance include but are not limited to the following: material thickness, material hardness, machine manufacturer cutting models, cutting speed (quality), nozzle settings, abrasive feed rate, machine calibrations, stack cutting, and operator skill. Other maintenance issues that affect part tolerance include wear and tear on the jewel, the focusing tube, the wear of the slat surfaces, and the need for pump pressure maintenance (rebuilds). The sales person representing a machine manufacturer will undoubtedly focus on the best tolerance scenarios. Buyer Beware!

To Think is to Create

Many people suppose that cutting steel for fabrication, or blanking out parts for manufacturing is the focus of a water jet job shop. Yes indeed we do a lot of this kind of work, but many folks don't realize the artistic possibilities that are at hand when you consider that you can cut almost any material in almost any geometry. To think is to create. It only takes creativity. I am always amazed at the different types of projects that cycle through our shop. I am not an artist, but I have helped create a lot of art.

It's Who You Know

Aerospace associated with government is a hard niche to break into when selling water jet cutting services. Most, if not all government contracts that are awarded are awarded to prime contractors. Thus a relationship must be developed with the prime contractor, and not with the government agency that is requesting a quote for particular parts. The federal government does not have an acquisition category for water jet cutting services. We are told that the federal government is the single biggest purchaser of goods and services in our country, but for a water jet job shop, it takes a creative person to get past the secretary, or the answering machine of the prime contractors who have secured these large contracts, and speak to the purchasing department. It seems to be who you know, more than the quality of your work, although quality is very important. Thus you can see that it requires a relationship with these contractors to effectively participate in government contracts. The problem becomes how to develop that relationship if you do not have an opportunity to "show your stuff".

Water Jet Cutting Advantages Over Laser Cutting

Laser cutting is a very productive process and certainly has its place, although it is usually on thinner material. However, waterjets do have several advantages over lasers:

Thicker materials can be cut. Up to 6".
No issues with reflective materials such as brass, copper, aluminum, and stainless.
No heat input, so there is no heat-affected zone (HAZ). Tempered materials can be cut with no change in temper. Of course excepting tempered glass.
Waterjets can cut materials which are heat sensitive such as plastics, rubber, or composites, and even such materials as glass, stone, and very hard ceramics.

Most Versatile Cutting Machine

Water Jet cutting machines are arguably the world's most versatile cutting tool. These machines can cut virtually any material into nearly any two dimensional shape, with edge qualities ranging from just separating the material to a smooth sand blasted look. They can cut materials in thicknesses ranging from foils to material over 8 inches thick. No other tool can cut or machine a greater variety of materials.

Water Jet Cutting

Water Jet cutting services make use of a super high pressure stream of water that carries an abrasive grit. This abrasive mixes with the water through a venturi effect in what is commonly called the “focusing tube” just prior to cutting. This mixture of water and abrasive grit exit the focusing tube at speeds of approximately mach 2.5. Cutting pressures range between 45,000 to 90,000 psi for standard cutting models. For brittle, fragile, or delicate materials, piercing pressures range between 15,000 to 20,000 psi, and resume the higher cutting pressures when the pierce has been completed. This low pressure pierce is not true of all machines, and cutting models.