The similarities and differences between laser cutting and waterjet cutting are not always as apparent as you might hope. In fact, it can sometimes be challenging to understand which is better, as each serves a specific purpose that can be more suitable for one project vs. another. To determine which type of cutting is better for your needs, you need to start by asking yourself some questions:
- What is it that you want to cut?
- What is the thickness of the material that you want to cut?
- What type of edge finish and tolerance are you seeking in your project?
- Will heat affect your finished part?
This article has been prepared to help you understand the differences between these two cutting techniques, and why waterjet cutting is often the superior method.
What is laser cutting?
Laser cutting, as it would imply, leverages a laser to melt and either burn or vaporize the material that is being cut. A focused beam of light is used to make the cut, and the laser is either static or moves across the material. Most laser cutters work best with materials that are between 0.12” and 0.4” thick.
Laser cutting is very commonly used when a flat sheet of medium thickness steel needs to be cut. However, laser cutters can cut through an expansive range of plastic, wood, glass, and metal, excluding highly reflective metals.
What is waterjet cutting?
Again, as the name would imply, waterjet cutting using highly pressurized water mixed with an abrasive substance. Many find waterjet cutting to be superior to laser cutting because the waterjet technique can cut through a wider range of materials and provide a very clean edge finish.
The advantages of waterjet cutting include:
- The ability to work with a wide variety of materials
- Can cut materials that are not well cut by laser cutters
- No heat-affected zones (HAZ) – laser cutters will often leave dark burn marks along the edge of the cut
- Environmentally friendly
- Safer than working with a laser
- The material does not need to be uniform
- Can cut through thicker parts
- Leaves a better edge finish after cutting
The cost of waterjet cutters vs. laser cutters
Plasma cutters tend to be the lowest in price, but they do not provide near the cutting ability of a laser or waterjet cutter. Waterjet cutters require ultra-high pressure pumps, which can bring the starting point of these cutters to $100,000 with many as much as $350,000 depending on the included features.
Laser cutters, even though they don’t provide the versatility of a waterjet cutter, are far more expensive. Most high-quality laser cutters start around $250,000 yet can easily exceed $1,000,000.
The extreme difference in price between laser cutters and waterjet cutters is another reason many fabricators go with the waterjet option.
Operating costs of waterjet cutters vs. laser cutters
After taking on the actual cutter's initial expense, the operating costs need to be taken into consideration. You will need to account for power and gas, as well as the cost of consumables and abrasives. Further, these machines will require maintenance to keep them in safe and effective operating condition.
When looking at operating costs by the hour, laser cutters are estimated at approximately $25 per hour. Waterjet cutters, however, are a bit more expensive, at approximately $30 per hour.
The production rate of waterjet cutters vs. laser cutters
After considering operating costs, the next expense is to consider production rates. Your production rate is judged by comparing cutting speeds and cutting tools. For example, a waterjet cutter with four heads can cut simultaneously, providing increased production rates. When comparing single heads per cutter, the laser cutter will be able to cut within the range of 20 to 70 ipm (images/impressions per minute). Waterjet cutters are slower, cutting between 15 ipm down to just a fraction of an inch each minute.
Cut edge quality of waterjet cutters vs. laser cutters
When talking about industrial cutters, the cut edge quality indicates the squareness of the finished edge. It also speaks to how the waste product or dross adheres at the bottom of the cut. Waterjet cutters provide the highest quality cut, which leaves very little if any waste product behind. Laster cutters also give a precise square cut, but they can leave some dross behind on thicker mild steel and stainless steel materials.
Though waterjet cutters do not require heat, this can pose problems when very small items need to be cut.
Cut art precision of waterjet cutters vs. laser cutters
Precision, specifically cut art precision, is all about how the resulting part size compares with the part size that was programmed into the cutter. It also takes into account the width of the kerf. Heat distortion can throw off the final size as well.
Waterjet cutters, by far, offer the best precision, usually within 0.005” of the intended part with a kerf width of 0.035”. Further, as mentioned previously, waterjet cutters do not create heat distortion. On the other hand, laser cutters cut within that same 0.005” and have an average kerf width of 0.025.” Unfortunately, laser cutters can create some heat distortion, notably on a thicker plate.
Flexibility of waterjet cutters vs. laser cutters
Flexibility is not as quantifiable as the previously mentioned aspects of cutting. However, fabricators and machinists will definitely consider flexibility. Further, shop owners will consider flexibility as part of their assessment of return on investment (ROI) for their cutter purchase.
Waterjet cutting is highly versatile as these cutters can cut through just about any type of material. Laser cutters are restricted to metals as well as some plastics, fiberglass, and fabric. If you want your shop to offer a wide range of services to your customers, it might be better to take on the higher investment that a waterjet cutter requires. Over time, this investment can pay off as customers wanting certain materials cut will not be turned away towards a competitor.
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