Fiber laser vs waterjet: which is best?

Many businesses are now looking at investing money to increase their production capabilities. For a lot of companies, the production line starts with a 2D cutting machine but, with so many different options out there, it is easy to get overwhelmed.  

In this article we will compare two of the more common cutting technologies: fiber laser and waterjet machines, looking at the pros and cons of each option. 

Visual 1: Fiber Laser cutting machine

So which option, fiber laser or waterjet is best for your business?

If cutting non-metallic materials is important for your business, a waterjet cutter is the only option. For metal cutting, if you need to cut highly intricate and accurate parts on thicker sheets (over 25 mm), again a waterjet is the obvious choice. If accuracy and heat distortion are not of the utmost importance on thicker sheets, a plasma machine may be a more cost-effective option. For more information on fiber laser vs plasma machines read our article here.

If thinner sheets make up the bulk of your cutting, a fiber laser is by far the ideal option. Their speed and accuracy make them an obvious choice for a wide range of industries.

The table below provides a summary of some of the key factors you may want to consider before purchasing either a 2D fiber laser or a waterjet cutting machine.

Table 1: Fiber Laser vs Waterjet- Key factor comparison

* Estimated data based on available market data
** May vary depending on the material and thickness being cut

In this article, you will find an answer to the following questions:

1. Material Versatility
2. Thickness Range
3. Edge Quality
          3.1. Heat Affected Zone (HAZ)
          3.2. Cut Edge
          3.3. Hole & Cut Quality
4. Productivity
5. Cost
          5.1. Purchasing Cost
          5.2. Operating Costs
          5.3. Maintenance
6. Safety

1. Material Versatility

Material versatility is always an important comparison point for different cutting machines. Between fiber lasers and waterjet cutting machines, waterjet is by far the most versatile cutting technology as it can cut almost any material (both metal and non-metal). The table below provides a summary.

Table 2: Fiber Laser vs Waterjet- Material Cutting Versatility Comparison

Fiber lasers are very sensitive to material textures and impurities as they can cause the laser beam to be distorted, reducing the energy available to cut the material (hence why it can struggle to cut through reversing mill mild steel). Cutting highly reflective materials such as copper and brass in high volumes on a fiber laser reduces the lifetime of consumable items. 

If non-metals are an important part of your business, then a waterjet is the obvious way to go. For the rest of this article, we will focus mainly on comparing the two technologies when cutting metals.

Visual 2: Non-metal piece cut detail

2. Thickness Range

The thickness range for a fiber laser machine increases with laser power. Additionally, higher-power lasers can produce dross-free cuts on thicker materials.  However, the pressure rating of a waterjet has a greater impact on the cutting speed than the cutting range. 

In general, a fiber laser machine will be able to cut up to 25 mm (with a 6 kW laser). Higher-powered lasers (10 kW +) may be able to cut thicker (<40mm) however, for high volumes, a fiber laser is likely not the most cost-effective option. If you need to cut large volumes of thicker materials, then you will likely want to consider either a plasma or waterjet machine.

Waterjets can cut material up to around 200 mm and potentially thicker although, they are much more expensive (both in terms of acquisition and operating costs) so unless high tolerances are necessary, a plasma machine will likely be the most cost-effective option. Find out more about plasma-cutting machines here.

Table 3: Fiber Laser vs Waterjet- Cutting Range Comparison

*Estimated data based on available market data

3. Edge quality

3.1. Heat Affected Zone (HAZ)

For some applications, parts must have no Heat Affected Zone (HAZ). Waterjet cutting is a cold cutting process (i.e. no heat is added to the material during cutting), preserving the structure of the material. The HAZ on a fiber laser is minimal, however, will vary depending on the cutting gas. Cutting with oxygen (typically used for thicker mild steel) will increase the thermal input into the cut. Sometimes, nitrogen is used instead of oxygen to minimize the effect of heat, however, this reduces the cut quality and produces more dross on the underside of the cut.

3.2. Cut Edge

The cut edge produced on a fiber laser has a striation pattern. Cutting too quickly causes the melt at the bottom of the cut to lag behind the cutting head causing the striation pattern to slant. This will eventually lead to the laser failing to cut through the material at a certain speed. Cutting too slowly results in a rough cut surface, as more heat is injected into the cut edge.

Waterjets produce extremely smooth cut edges, often without a striation pattern. As the waterjet cutting head moves along the cut path, the beam overlaps itself, going over what has already been cut producing the smooth cut edge.

Visual 4: Cut edge produced on a waterjet

Both fiber laser and waterjet machines have various cutting parameters that can be adjusted to get the best cut-edge quality. To achieve a consistent cut, maintaining the correct height above the workpiece is extremely important. Fiber laser machines have automated height controls, meaning the cutting head will automatically adjusts itself to account for material warpage. However, on waterjet cutting machines the height control has to be adjusted manually. If this is not done/ is done incorrectly, the head could hit the sheet and snap the nozzle. Adjusting the height requires the pump to be stopped, the nozzle replaced and the garnet line cleared before the job can be restarted (although in certain applications, these parts may be scrap).

3.3. Hole & Cut Quality

On thinner materials, both fiber laser and waterjet machines will be able to produce almost perfect holes. As you get thicker (approximately 10 mm and above), while a fiber laser will still produce an excellent cut, a waterjet will produce slightly better results. 

Table 4: Fiber Laser vs Waterjet: Hole & Cut Quality Comparsion

*Estimated data based on available market data

4. Productivity

Productivity is most easily judged by comparing cutting speeds. A fair evaluation would also need to include the number of cutting tools as it is possible to have four waterjet cutting heads cutting simultaneously on the same machine. 

When it comes to cutting speed, fiber lasers are by far superior and can be anything up to 10 times faster on thinner materials (less than 5 mm). For thicker materials, (above 10 mm) if speed is a priority, a plasma machine may be a better option. Find out more here. 

The graphs below show some examples of cut speeds you can expect from both a waterjet and fiber laser (cut speeds are based on market data, speak to machine manufacturers for exact values). The exact speeds used for cutting may vary depending on what is being prioritized: speed or cut quality.  

*Estimated data based on available market data

Graphic 1: Mild Steel

Graphic 2: Stainless Steel

Graphic 3: Aluminium

5. cost

5.1. Purchasing Cost

When deciding what type of machine is best for your business, the initial acquisition cost is perhaps the most important factor in any purchasing decision. 

The exact acquisition cost of a machine will vary depending on the specifics of each machine. The two major factors are:  

• • Power/Pressure specification of the machine
  • Cutting table size

Other factors that may affect the price are the number/type of cutting heads, automated systems etc. Estimate costs are shown below. 

Table 5: Fiber Laser vs Waterjet: Purchasing Cost

*Estimated data based on available market data

5.2. Operating Costs

Calculating the true operating cost of any machine is no simple task as it requires careful consideration of a wide number of different factors: power, consumables, labour etc. Other costs will be specific to the cutting method i.e. cutting gas for fiber laser and garnet for waterjets. 

When labour costs are factored in, these will likely account for the majority of the overheads. 

As with any machine, regular servicing is strongly recommended to minimize the likelihood of machine breakdowns. Most machine manufacturers will offer regular service visits. The recommended number of visits per year will vary depending on the machine’s usage. 

Fiber Laser

Operating costs will vary depending on the material and thickness being cut. Nitrogen is more expensive than oxygen, and when cutting thicker materials, the gas alone accounts for approximately 60%* of the hourly operating costs. Cutting with oxygen, however, typically for thicker mild steel, often reduces the lifetime of the consumables as the lower gas pressures make it easier for debris to go back up the nozzle damaging the protective window. As the power of a laser increases, the lifetime of the consumables decreases. 

The high energy efficiency of fiber lasers and generally low operating costs, combined with their high cutting speeds bring the cost per meter down.  

*Based on cost calculations where power, gas and consumables were accounted for.

WATERJET

As with a fiber laser, the exact operating costs will vary depending on what you are cutting and also, the cut quality you require. If cut quality is your top priority, you may need to slow the cutting speed down and increase the amount of garnet, however, this will increase the cost per meter of cutting. In general, consumable costs are higher than those of a laser. Further to this, the risk of human error when it comes to consumables on a waterjet machine is higher than for a fiber laser machine which could result in higher operating costs. For example, operators need to be extremely vigilant and monitor the pressure/cut quality to spot any errors as the pumps will fail instantly.

5.3. MAINTENANCE

A CNC cutting machine is often a crucial bottleneck in the overall production process. If the machine breaks down, it often has major implications and could even put a halt on production. This is why preventative maintenance is important to factor into your buying decision.

Fiber Laser

Even though fiber laser machines are fairly complex machines, many processes are automated and hence there is minimal operator interference for maintenance. Standard maintenance tasks include:

• • • • • • Clean daily slag bins/slats
          • Always check the assist gas when switching the gas on and check valves on gas bottles every time you replace one 
          • Daily check of consumables (window) to make sure it is clean and free of debris 
          • Check water coolant levels in the chiller are adequate for your laser cutter 
          • Monitoring for wear on the slats (wear will vary depending on the material/thickness being cut) 
          • Standardize routine controls and checks in your checklist 
          • Service machine by experts: 1-4 times a year depending on your usage

WATERJET

To maintain a waterjet the following tasks are strongly recommended. While these maintenance tasks are easy to complete, they may be more time-consuming than those on a fiber laser as gaining access to pipes for example can be more difficult.

• • • • • • Monitor closely the high-pressure plumbing, pump, filters, abrasive and water tank levels, ideally via specialized software
          • Perform daily checks for leaks in the pump & all high-pressure plumbing components 
          • Monitoring for wear on the slats (wear will vary depending on the material/thickness being cut) 
          • Only work with high-quality abrasive & keep it dry & free of debris 
          • Always check the quality of water as this will have the biggest impact on the lifespan of most components 
          • Always have spare components on hand 
          • Service your machine by experts: 1-4 times a year, depending on your usage

6. safety

Nothing is more important than the health and safety of your operators and staff therefore it is important to be aware of the potential hazards and any safety measures required for different types of cutting machines.  

The wavelength of a fiber laser is invisible to the human eye and if exposed can cause serious damage to both the retina and the skin. A fiber laser machine without the correct enclosure can be extremely dangerous to the operator and those in the same room. For machines with enclosures, any viewing panels will be made from a special protective glass which is safety rated. This glass is expensive and can increase the cost of a machine. 

Additionally, fiber laser cutting machines emit hazardous fumes when cutting different materials. To counter these, the machine will require an adequate extraction unit to remove any potentially damaging particles from the air, making it safe to breathe. These extraction systems will likely add to the cost of a new machine. If you wish to cut both mild steel and aluminium, you will need a reinforced filtration system due to the risk of an explosion. 

Table 6: Fumes emitted by material type

Waterjet cutting machines are associated with high volumes of noise which can cause hearing damage if adequate ear protection is not worn. 

During cutting, there is the risk of injury because of particles (water, abrasive, cutting material etc.) which have the potential to cause damage when inhaled or cause retina damage. Despite the dispersion of various particles during cutting, waterjets do not require large filtration systems as no hazardous fumes are produced. 

CONCLUSION

As with everything, fiber laser and waterjet cutting machine have their merits, however, for your business, there will likely be an optimal choice. 

When it comes to cutting thin metal sheets in high volumes, a fiber laser machine is an obvious choice. The fast cutting speeds combined with their high tolerances make it an ideal choice for a wide range of industries. 

If your cutting requirements vary greatly in material and thickness, a waterjet cutting machine is by far the best choice. Their flexibility will enable you to meet all your cutting needs and the complete lack of heat makes it the preferred choice for certain applications. 

If you have any questions about fiber laser machines or are looking for some expert advice on what technology: fiber laser, waterjet or even plasma, please do not hesitate to contact us. 

Our team of expert engineers would be more than happy to help you to identify the right CNC cutting machine for you. They’d be delighted to talk through your specific needs and how Esprit Automation could help you to meet them.