Power of the elements
 

We all know that water is a very useful substance, used extensively in the print and sign industries. Offset lithographic printing is impossible without it – although waterless printing is still used by some companies. We also use it for cooling, washing and cleaning but how many of you know it can be used for cutting a large number of materials?

Water has been used to erode, and hence cut materials, as early as the mid 1800s but it was not until 1933 when the first patented plans for a waterjet device were lodged by the Paper Patents Company in Wisconsin. Research continued into the 1950s by mainly aircraft companies in search of a cutting device producing an accurately cut substrate with a good surface finish.

Waterjet applications come in two basic designs, one with abrasive mineral additives, the other for softer materials without, using just water. Both devices have, as a basic design, the cutting head itself straddling a shallow bath of water with a support frame sunk just be below the water surface which holds the substrate being cut.

The basis of waterjet cutting is quite simple but the fundamental design stretches engineering technology to the limits. Basically, if you push water through a very small orifice at very high pressures, the stream of water that passes out has enough force to allow it to cut everything from plastic up to stone and the strongest of metals.

The pressure is relative, we have domestic water pressure somewhere around 2 bar or 28 pounds per square inch (psi). Now, consider you are using a pressure washer to clean the paving slabs on a pavement, we have all seen how the jet of water hitting the slabs cleans off all surface debris leaving you with an ‘as new’ looking pavement. The pressure your jet washer is cleaning the pavement at is around 130 bar or 1,900psi.

When you want to start to actually cut metals for instance, the typical waterjet cutting device has water pressure at an incredible 3,500 bar or 50,000psi. Clearly, to reach these pressures, the level of engineering that goes into the pumps and seals is extremely specialised, but the application of the equipment itself is very simple as we saw in the latest machine from AXYZ, the American-made WARDjet X-Series.

The X-Series of waterjet cutters come in three basic models, the X-1515, X-1530 and the very large X-2040. The model names have a correlation to the cutting area each can produce. They start with the X-1515 with a cutting area of 1.52 x 1.52m, the X-1530 with an area of 1.52 x 3.05m and the largest version the X-2040 with a vast area of 2.04 x 4.0m.

As explained, at the heart of each machine is the pump itself. Waterjet devices come with two designs of pump, crankshaft or intensifier style. As with any differences in basic design, there are pros and cons which either but AXYZ has installed in their machines Hyperthem intensifier style pumps.

AXYZ’s reason for choosing this type of pump is the maintenance cycles on them are much lower than the competition and they work the best in tandem with the Advanced Intensifier Technology (AIT) found in the three models. AXYZ claims the use of AIT means the device can work for longer, harder and requires much less service time, typically outperforming similar equipment by 20%.

The AIT system has further benefits when cutting any substrate. Electronics are used to smooth out the pulsing of the water under pressure, improving cutting outcomes. Advanced piston design reduces the wear on seals which are the Achilles Heel of any waterjet system. Large ceramic pistons move more water per stroke and a threadless design of the high pressure end of the pump makes maintenance easier.  

Each of the devices is very similar in design, the size being the only major difference between them. The cutting head is held on an over arch which straddles the width of the water bath. There are two major axes (X and Y); this being the principle method for placing the cutting head to a specific place on the substrate to be cut. Each being driven by a Computer Numerical Controller (CNC), stepper motors on each. This allows you to program the shape you need and have it reproduced to within +/- 0.025mm.

When it comes to how to get your images to the device, AXYZ has a clever motion control system called Move. There is a very simple Graphic User Interface (GUI) that will allow you to drag and drop the desired shape from the job queues and place it on any place in the substrate frame.

You can move, rotate, zoom and complete any operation on the Move GUI as if you were working on a tablet; in fact AXYZ state a USP being the fact it has been designed to work just as your tablet. There are lots of other functions embedded in Move such as input/output commands (I/O’s) for water, nozzle height and abrasives (if used). Notifications are shown up on the Move GUI and the format of the screen itself can all be altered via the simple touch screen icons.

So, with the technical issues all explained, why would a printer or a sign-maker be interested in buying a machine capable of cutting Titanium? Whilst it is true any waterjet machine can cut some of the hardest materials, it can equally cut some of the softest with the same accuracy and complexity.

With the high street looking to add to the multi-sensory shopping experience, point of sale promotions in plastics, foams and rubber based substrates all are being used to provide the ‘wow’ factor. As explained, the AXYZ WARDjet can produce the most accurate and intricate designs via the programmable controller. So it is easy to produce the shapes, contours and profiles of materials impossible to cut with traditional die-cutters, all done at the press of a button.

Furthermore, expensive dies and forms are not needed for general production, the storage of these being held in the controller and not as with bespoke die-cutter production elements, held in large storage areas. Lead times for die-cutting can be cut to minutes from days; you do not need to produce a cutter, just a program.

Clearly these machines are not for every printer or sign-maker, but with the diversity we need to produce for the ever imaginative client base, the use of new technologies for new products gives forward thinking printers food for thought.     

Brian Sims principal consultant, Metis Print Consultancy, www.metis-uk.eu

kiuipoiqwyjbcfetetyhtyhtukkkikqzzrrrepllkikmgjthgq