There are several different technologies available in the fast moving industry of laser and waterjet cutting. In this comparison we will cover laser, waterjet, and micro waterjet cutting technologies to provide the best possible guidance on the difference in the technologies, their strengths and weaknesses, in order for you to choose the best fit for your cutting needs.
Waterjet Or Laser, Which Is Better?
As a manufacturer or fabricator the focus is on cost, speed and cutting capabilities. The waterjet and the laser are both capable of cutting a variety of materials at high speeds. The choice of which one is more accurate, faster, and better for production is determined by your needs and what will bring value to your specific application.
In the following we will provide you with a condensed comparison of the following waterjet and laser cutting machines:
- laser cutting
- femtosecond laser cutting
- waterjet cutting
- micro waterjet cutting
How a Laser Cutting Machines Work
Laser technology is based on a light beam focused to a fine point creating very high power density. The light is characterized by the light beam being highly parallel and of one single wavelength. There are several different laser technologies available. The most common ones are:
- Fiber laser (continuous laser)
- Femtosecond laser (pulsed laser)
- CO2 laser
Fiber Laser – How it works
Fiber laser cutting generally uses a high-power diode laser that emits light that is directed through a fiber-optic cable to a cutting head. The light can be of different wavelengths depending on the laser source. The choice of wavelength depends on what material is being cut. The laser can either be continuous or pulsed. A fiber laser cutting machine generally operates with a continuous laser.
The laser cutting utilizes the beam focused to a small focal point creating a high power-density, so that the target material is rapidly melted, vaporized, ablated, or ignited, and the molten material is blown off by a high-speed gas flow coaxial with the beam, thereby cutting the workpiece. The gas can also have the function to protect the cut surface from surrounding air (oxidation).
A motion system operated by computer numerical control (CNC) is used to program the path of the beam over the material. Typically, the machine uses a motion control system to follow a CNC or G-code program of the pattern that is to be cut onto the material.
Working with the lasers requires eye protection which is important as the invisible laser light can injure the eye.
Femtosecond laser – how it works
A femtosecond laser creates bursts of laser energy at a high rate of speed. It is measured in femtoseconds, which is one quadrillionth of a second. Femtosecond lasers are used to target and break down materials all the way to the molecular level, without damaging the surrounding areas.
The femtosecond laser is an ultra-short pulsed laser capable of producing pulses with a temporal magnitude in the x10-15 second range (e.g. 1 fs = 1×10-15s). The short pulse has a high power, which instantly vaporizes the material. This eliminates heat transfer to the material and there are no heat affected zones. Utilizing a femtosecond laser, finer, more precise geometries are possible due to low thermal distortion during cutting and kerf widths (i.e. cut width) as small as 5 µm resulting from a high quality laser beam. The process also has the ability to partial penetration ablation which means you can make surface texturing.
The process is somewhat demanding to set up – cut speed, pulse frequency and laser focus must be optimized to get a good result. A non-optimized femtosecond cutting process can lead to thermal damage such as re-deposited debris, re-cast layer on the cut wall and heat affected layer; similar to that observed from a traditional thermal laser cutting process. The Femtosecond laser has the capability for cutting most materials.
The process has low average power, which means it is slow for cutting but very accurate. Tolerances can be as good as micrometer precision level. Suitable material thickness is generally below 1 mm.One of the most common usages for femtosecond lasers is in machining medical parts such as stents, catheters and even more.
How Waterjet Machines Work
Waterjet Cutting – How it works
Waterjet cutting is basically an accelerated erosion process within a selected material. Highly pressurized water is released through a ruby or diamond nozzle into a mixing chamber. This pressure creates a vacuum and draws garnet sand into the stream where it is then targeted at the object in place for cutting.
A traditional abrasive waterjet machine can typically provide cutting tolerances down to ca ±0.1 mm depending on the part geometry and material. It is versatile and easy to set up. It pierces starting holes and cuts contours in the same setup.
The waterjet process can cut all materials without heat influence. Thus, the material properties remain unchanged at the cut surface. Material thicknesses up to 300 mm have been demonstrated.
Typically the jet diameter is in the range of 1 mm. The abrasive waterjet cut surface is generally characterized by a smooth upper section transitioning to a slightly striated lower section. The surface quality is highly dependent on cutting speed, which means that this tool can be optimized for either high quality or speed.
Micro Abrasive Waterjet Cutting – How it works
Micro abrasive waterjet cutting is different from traditional abrasive waterjet cutting when it comes to accuracy, edge and surface quality, and kerf width. This process shares the general benefits of traditional waterjet described above but expands the applications to fine mechanics.
Ultra-High Precision & Quality
On a micro abrasive waterjet machine the jet stream diameter is very thin (down to 0.2 mm) and more coherent compared to traditional waterjet. To produce precise parts it requires a machine tool designed for high precision motion. Under these conditions the waterjet can be used for ultra-high precision cutting to tolerances down to +/- 0.01 mm or even better.
The micro abrasive waterjet utilizes a precision powder garnet which produces very fine surface finish. A servo controlled abrasive feed is required to obtain a stable process.
This extremely precise cutting process offers an enormous variety of possible applications within industries that rely on ultra-high precision, surface and edge quality, and cost efficiency. Micro abrasive waterjet machines can now offer what, for a long time, was not feasible with traditional waterjet machines.
A Detailed Comparison: Laser vs Waterjet Cutting Machines
| Micro Waterjet | Waterjet | Femtosecond laser | Laser | |
|---|---|---|---|---|
| Typical tolerance on cut part | +/- 0.01 mm | +/- 0.1 mm | 1-5 micron | +/- 0.1 mm |
| Typical Thickness | 0.02-30 mm | 0.5-300 mm | <1mm | 1-20 mm |
| Kerf width Ø | 0.2- 0.5 mm | 0.5-1.5 mm | Down to 5µm | 0.1- 0.5 mm |
| Cutting power | 2-15 kw | 10-30 kW | 20-50 W | 0.5-6 kW |
| Run-time per part | Long | Short | Long | Short |
| Typical Edge quality/surface roughness | Fine | Medium/ Rough | Excellent | Rough |
| Toxic gas or vapor | No | No | Depending on material cut | Depending on material cut |
| Material distortion | No | No | No | Yes |
| Heat Affected Zone | No | No | No | Yes |
| Micro cracks | No | No | No | Yes |
| Material limitations | No | No | ? | Yes |
| Fixturing required for typical part | Yes | No | Yes | No |
| Cutting process | Non-thermal | Non-thermal | Thermal | Thermal |
| Ease of use | High | High | Low | Medium |
| Typical Cost per part | medium / high | low | high | low |
Machine Cost
| Machine USD | Cost Per part | |
| Abrasive Waterjets | $60,000 – $500,000 | Low |
| Micro Abrasive Waterjets | $300,000 – $700,000 | Medium / High |
| Laser Cutting machines | $50,000 – $300,000 | Low |
| Femtosecond Laser Cutters | $400,000 – $800,000 | High |
Operating costs
| Cost per part | Running cost | |
| Abrasive Waterjets | Low | $15-$30 per hour |
| Micro Abrasive Waterjets | Medium & High | $15-$30 per hour |
| Laser Cutting Machines | Low | $13-$20 per hour |
| Femtosecond Laser | High | Ask Lasea! |
Waterjet machines require some consumable items such as nozzles, seals, water, electricity and abrasive material (garnet).
Laser cutting machines consume gas for cutting and also have nozzles, protection glass and lenses that need to be replaced. They also require repair or replacement of the laser tube every 2 years approximately, and the biggest cost of operation is electricity of which the laser consumes a significant amount.
Waste
Laser cutting: The molten metal or material debris from the cut is collected in the machine table. Besides that gasses can be produced that are sometimes toxic, especially for cutting polymers, for some materials containing chrome like, stainless steel, the very hazardous Hexavalent chromium [Cr(VI)] can be emitted.
Water jet cutting : These involve cleanup and disposal of the abrasive material which is collected in a catcher tank. The abrasive media itself can normally be used as landfill but how to handle the waste ultimately depends on the potential toxicity of the material being cut.
Cutting Capabilities
| Complex Cutting | Thickness | Hole / Pierce | |
| Abrasive Waterjets | Complex 3D cutting | 0.5-300 mm | can pierce or drill holes |
| Micro Abrasive Waterjets | Complex 3D cutting | 0.2-30 mm | can pierce or drill holes |
| Laser Cutting machines | Complex 3D cutting | 1-20 mm. | can pierce or drill holes |
| Femtosecond Laser | Complex 3D cutting | <1mm | can pierce or drill holes |
Material & Application
| Can Cut | Can NOT Cut | Application | |
|---|---|---|---|
| Abrasive Waterjets | Aluminum, Copper, Brass, Glass, Titanium, Plastic, Rubber, Composites, Armor Plating | Diamonds, tempered glass | Industrial parts with low precision requirements, where material integrity is important. |
| Micro Abrasive Waterjets | Nitinol, Shape Memory Alloy (SMA), Magnesium, Aluminum, Gold, Silver, Copper, Brass, Glass, Titanium, Plastic, Rubber, Composites, Armor Plating | Diamonds, tempered glass | Medical device, luxury watches, electronics, and other precision components |
| Laser Cutters | Stainless Steels, Carbon Steels, Steel Alloys, Thin Aluminum | Transparent materials, and reflective materials. | Industrial parts with low precision requirements, where speed is important. |
| Femtosecond Laser Cutters | Stainless Steels, Shape Memory Alloy (SMA), Gold, Nitinol, Magnesium, Carbon Steels, Steel Alloys, Thin Aluminum | Medical device, luxury watches, electronics, and other precision components |
Cutting Speed & Accuracy
| Cutting Power | Accuracy | |
| Abrasive Waterjets | 10-30 kW | +/- 0.1 mm |
| Micro Abrasive Waterjets | 2-15 kw | +/- 10 micron |
| Laser Cutters | 0.5-6 kW | +/- 0.1 mm |
| Femtosecond Laser Cutters | 20-50 W | 1-5 micron |
Ease Of Use Finecut Micro Waterjet Technology
The waterjet technology is easy to set up and use. By adjusting speed both tolerances and surface quality can be selected. High accuracy parts will need a special fixture to keep material fixed during cutting. The Finecut machine has a user friendly operator interface that does not require any CNC operator skill.
In Conclusion
As there are many aspects of the requirements to consider when you are choosing production technology for your parts, it is hard to give a clear guideline for when a production technology is preferred before any other. As a rule of thumb, following advice can be followed: