Can a jet of water cut a diamond

FAQ

Material thickness and cutting accuracy in comparison - laser / plasma / EDM / water jet?

Can, a higher accuracy can be achieved with water jet cutting than with a flame or plasma cutting system. In addition, waterjet cutting systems cut higher material thicknesses than laser systems.

Furthermore, waterjet cutting machines have numerous other advantages over other solutions.

 

What cutting accuracy can I expect from waterjet cutting?

Can, a higher accuracy can be achieved with water jet cutting than with a flame or plasma cutting system. In addition, waterjet cutting systems cut higher material thicknesses than laser systems.

Furthermore, waterjet cutting machines have numerous other advantages over other solutions.

 

Should I cut underwater?

The biggest advantage is the reduction of the cutting noise to below 75 dBA. One negative side of underwater cutting is that the workpiece is difficult to see, if at all, while it is being cut. The workpiece handling also takes place under water - unless you have a water level control in the water tank. It should also be said that the cutting process suffers a reduction in performance of approx. 5% when there is 1mm of water coverage

Up to what thickness can I cut?

Up to 200mm thick steel and titanium are cut on a production basis. There are cases where thicknesses of 300 mm and 400 mm have been cut. However, the majority of users cut material with thicknesses between 10 mm and 60 mm.

How much water is needed at 400MPa cutting pressure?

That depends on the performance of the HP pump or water nozzle.


 

HP pump: water nozzle:

19 kw: 1.9 l / min 0.1: 0.32 l / min
37 kw: 3.8 l / min 0.15: 0.71 l / min
45 kw: 4.6 l / min 0.2: 1.22 l / min
75 kw: 7.6 l / min 0.25: 1.87 l / min
0.35: 3.57 l / min
0.4: 4.60 l / min
0.5: 6.82 l / min

How wide is the kerf?

The kerf is approx. 15% wider than the focusing tube diameter. With a 0.8 mm focusing tube, the kerf is 1.0 mm wide. As the diameter of the focusing tube increases, the kerf also widens.

How strong is the tapering of the kerf?

The resulting taper is a function of the cutting speed. The largest possible taper is equal to the maximum cutting width on the material surface (e.g. 0.8 mm) and 0.0 mm on the underside of the material. As you reduce the cutting speed, the taper also gets smaller until you get parallel sides. The usual taper for precision cuts is between 0.05 and 0.10 mm.

Do I have to drill a starting hole?

With most materials, the water jet creates its own starting hole (connection) without any further effort. With some composite materials, the pump pressure must be reduced and a special vacuum connection device must be used.

How is the beam slowed down?

Of 700 mm of water in the water tank.

What water quality is required?

There are the following minimum requirements for water quality:

  • pH value 7.0 - 8.5
  • Carbonate hardness 20 - 60 ppm corresponds to 2 - 6 ° dH
  • Calcium carbonate (Ca) 35-107 ppm
  • Chloride content (Cl)? 100 mg / l
  • Inlet temperature for feed water 10 - 25 ° C
  • Electrical conductivity at + 25 ° C 450 µS / cm
  • Filtrate dry residue 350 mg / l
  • Free, dissolved chlorine 1 mg / l
  • Feed water inlet pressure 0.2 - 2.5 MPa

Deviations from these values ​​lead to shorter service lives of the high-pressure seals of the pump and the nozzles. We therefore recommend a water analysis and, if necessary, appropriate water treatment.

Which electrical connection do I need?

A connected load of 37 kW must be taken into account for each installed abrasive cutting head.

When and how do I use more than one cutting head?

You use several cutting heads if you want to produce a large number of identical parts. Either a second cutting head is attached to the existing z-axis, or a second z-axis is installed, to which further cutting heads can then be attached. It is important here that each individual cutting head must be supplied with the same pressure and the same flow rate in order to be able to achieve an even cut.

How long does a high pressure pump maintenance interval last?

The high pressure seals must be replaced if they are leaking! With a constant working pressure of 400 MPa, the seals should be replaced after 400 to 1,200 cutting hours.

Which abrasive do I use?

Garnet sand is by far the most widely used abrasive. It convinces in the areas of acquisition costs, cutting speed, service life of the mixing head and health risks. Other abrasives include olivine sand, aluminum oxide, and some man-made materials.

How much abrasive do I need?

At 400 MPa working pressure you need for optimal cutting performance:

Nozzle 0.15 mm / focus 0.6 mm 150g / min
Nozzle 0.25 mm / focus 0.8 mm 350g / min
Nozzle 0.35 mm / focus 1.0 mm 450g / min

How long does the workpiece support last?

The shelf supports last many hours of cutting, provided you don't always cut in the same place. The grids can be shifted, exchanged and turned around, as with laser or plasma cutting systems.

How long does the focusing tube (= the focus) last?

Foci made from good ceramic carbide last around 100 hours. Foci made from the highest ceramic carbide quality last around 30% longer than foci made from other materials.

Such a focusing tube can provide up to 150 cutting hours with an expansion of the diameter by 0.5 mm. Many of our customers are already using somewhat used foci for the production of parts that do not require high accuracy.

How long does the water nozzle last?

A sapphire nozzle lasts 25 hours of cutting. A diamond nozzle (the highest nozzle quality) lasts much longer, but costs 30 times more and is normally only used for pure waterjet cutting.

Are waterjet cutting systems easy to program?

With the StM SmartCut, the flexibility of the water jet can be fully exploited. At the same time, the suggested strategies and the intuitive user interface make it very easy to operate. The software communicates directly between the waterjet cutting system and a standard office PC as a CNC control unit. StM SmartCut allows faster processing of cutting requirements and does not require any special CNC or IT knowledge.

How do I clamp the part to be machined?

Since the force acting on the workpiece is very small (less than 1 kg for precision cuts and less than 5 kg for average cuts), there is no need for complex clamping devices. Most users use simple, light weights to keep their workpieces stable.

Why should I work with a waterjet system and not with a laser?

Laser cutting is a very productive process. Nevertheless, the water jet has some advantages over the laser:

  • No strength restrictions
  • No problems with reflective materials like brass and aluminum
  • No heat influence, so there is no burning and no change in the material structure due to heat
  • With the water jet, heat-sensitive materials such as plastic, rubber or composite materials as well as glass, stone and very hard
  • Ceramic can be cut
  • Material change: only the cutting speed is changed. Neither gas nor optics have to be changed
  • Additional cutting heads can easily be attached for expanded production
  • Maintenance of laser systems is more specialized and difficult to carry out
  • The distance between the nozzle and the material is nowhere near as critical
  • Water jet systems are less capital-intensive to purchase than lasers

Why should I work with a waterjet system and not with EDM?

EDM is very accurate, but also very slow. It also requires an electrically conductive material and causes a change in the structure of the material through heat.

Why should I work with a waterjet system and not with a milling cutter?

If you want to cut the edge of the material and holes or create blind holes and threads, the abrasive water jet is usually much faster, easier to program and also cheaper than a milling cutter.

This is mainly due to the fact that we cut through in one go and that we do not generate metal chips. Additionally, waste is worth more in its entirety than in chip form.

What are the advantages of water jet cutting compared to plasma / oxy-fuel cutting?

Plasma cutting is a heat process. It adds large amounts of heat to the workpiece and leaves a heat affected zone.
The surface created by a water jet is generally better. There is no burr on the underside of the material, so post-processing is not necessary. The abrasive water jet is not subject to any restrictions on the cutting thickness and several working areas of a jet can be close together.

How much is charged for contract cutting on water jet systems?

Usually, between € 120.00 and € 220.00 per hour are charged for contract cutting on abrasive waterjet cutting systems.

How high are the operating costs of a waterjet cutting system?

The hourly costs start at € 19.00 for a small cutting head (nozzle: 0.15 mm / focus 0.6 mm) and go up to € 35.00 for a large cutting head (nozzle 0.35 mm / focus 1.0 mm). The amount includes all machine-related costs. Labor, leasing and depreciation have to be added.

How much does the abrasive cost?

The abrasive costs between € 280.00 and € 300.00 per ton ex works A-5531 Eben im Pongau.

What happens if my finger gets in the jet?

He is cut off. The safety equipment around the machine was therefore planned very carefully. The users of abrasive waterjet cutting systems are subject to stricter safety requirements than most machinists in other industries.

How loud is it when cutting?

The generation of noise during water jet cutting depends on the distance between the free jet and the workpiece surface - i.e. the distance in which the water jet moves in the air at supersonic speed. If you cut under water, the noise level drops below 75 dBA. If you cut over water, the noise level rises to up to 105 dBA, depending on the distance between the cutting head and the workpiece surface. In extreme cases, the entire work surface is covered.

How is the wastewater disposed of?

Neither the water nor the garnet sand contain toxic substances. Therefore, after the suspended matter has settled or has been filtered out, the water can be directed into the sewer. The abrasive can be disposed of as construction waste. If the processed material is toxic or hazardous to health, waste water and abrasive must be disposed of as special waste!

Is it pure water?

Yes. Most customers use tap water. Before the high pressure pump, the water must be filtered to 0.5 microns. Deionization and osmotic systems are not recommended. Such systems purify the water too much - and water that is too pure is extremely aggressive, which leads to increased wear and tear on the high pressure system.

Can i recycle the water?

Water and abrasives can be cleaned and recycled with the ONECLEAN system. You can find more information on the OneClean System subpage.

Waterjet service d.o.o. / A: Mate Balote 1, Poreč / E: [email protected] / T: 0976937225
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