When it comes to keeping your project on track, the work your fabrication partner will do can make or break the whole design process. Most modern fabrication shops have both water jet cutting and laser cutting available to ensure every project is cut precisely to order. While these two processes are similar (and interchangeable in some instances), their subtle differences are important. That’s why it’s important you know which method is better for your project so you can avoid any potential imperfections.
What are the significant differences between using a water jet or laser cutter?
High-pressure water cutters have been used since the 1800s after it was first used in the mining industry to cut through rock. Over time, the ability to achieve incredibly high pressures and adding in abrasive materials have made water, effectively, one of the sharpest and accurate cutting tools available.
Lasers came later, but their development has been rapid. Initially used to bore small holes in diamonds, the technology has advanced to where they can now cut most metals with very little waste. Although water jet and laser cutting do the same thing, they are not as interchangeable as you might think.
Here’s what you should know before you send your parts to a fabrication shop.
- Your materials will determine which cutting method to use
Water jet cutting is far more versatile than laser cutting. It can handle just about any type of metal but is also great with other materials like stone, glass, composites, and plastics. Any non-metallic materials in your project will most likely be suitable for water jet cutting, but not laser cutting.
There are three basic laser cutter technologies, C02, Crystal (Nd:YAG/Nd:YVO), and Fiber. Each can cut different types of material, but none will effectively cut all of them. Because of their initial expense, your fabrication partner may not have all three. Here’s a quick rundown of what each laser is specialized in cutting.
CO2:
A CO2 laser runs electricity through a gas-filled tube to produce the laser. CO2 lasers are great at cutting acrylic, leather, plastics, fabrics, MDF, paper, foam, fiberglass, rubber, wood, carbon steel, and stainless steel.
Crystal (Nd:YAG/Nd:YVO):
Crystal lasers can be used to coated and non-coated metals. They are also able to handle cutting non-metals like plastics and ceramics.
Fiber:
A fiber laser cutter is able to cut all types of sheet metal. This includes carbon steel, stainless steel, aluminum, titanium, and copper.
Knowing the capabilities of each type of laser and asking your fabrication shop which technologies they have could save you a lot of headaches. Sometimes fabrication shops get an order for work they have never done before, take on the job, and then find they can’t do it. Knowing your lasers and asking the right questions will give you assurance your partner is a good fit.
- Understand that how heat will affect the final product
Laser cutters put a lot of energy into a very small point as they slice metal. This creates heat build-up near the cut, known as the “Heat Affected Zone” (HAZ). With enough heat buildup from laser cutters, the properties of the metal can change along with warping, melting, and thermal damage.
In contrast, water cutting is a cold process. The thickness of the materials will influence how long it will take to make the cuts, but the material itself will not be affected by heat. Even with abrasive additives in the water to speed the process, any significant heat that is generated is carried away by the water itself, preserving the properties of the initial metals.
It’s important that the properties of your metal stay consistent. Even though water jet cutting may be a slightly longer process, it may end up being more efficient in the long run by reducing the amount of finishing work that needs to come after.
- Material thickness can make one form of cutting better than the other
Not only do laser cutters come in three varieties, they also come in a range of power levels to help with thicker materials. If you are leaning towards laser cutting, but the material is around 0.6 inches thick or more, you will want to dig into this a bit deeper. Ask your fabrication shop about their laser cutters, and take into account the HAZ that will develop from the increased time it takes for the laser to bore through the metal.
As the material gets thicker, water jet cutting becomes the more accepted option. Practically speaking, a water jet will be able to cut any depth that is likely to be needed in a typical engineering project.
The cutting precision will decrease with depth as well. Most fabrication shops should be able to handle around 5 inches of depth, with some up to a foot. The fabricators you speak with should be able to definitively explain how the depth of the cut will affect the final product in both time and precision.
- There will be a lot of factors that determine precision and accuracy
By all accounts, both methods of cutting can be considered “high precision.” The laser can cut a smoother edge that needs less finishing work, as long as the HAZ is not an issue. It can also cut a much finer line between edges. And as an added bonus, if you need your materials to be inscribed, a laser can do that too.
While water jet cutting has a wider cut and slightly rougher edge, its ability to quickly cut thicker and various materials often make it a good choice. In some instances, the water jet can even meet or exceed the precision of the laser cutter. If your project calls for very defined angles in your cuts, a laser may be able to do it, but the resulting HAZ will end up taking the angles out of spec. A water cutter can cut those tight angles and leave you with better tolerances by not changing the properties of the metal.
Again, it’s good to ask questions. Your fabrication partner should fully understand the capabilities of their technology and be able to apply it to your design specs. They should be able to see in your design what you are trying to accomplish and alert you to potential issues of using specific cutting technology in your project.
When technology overlaps, how do you make the right choice?
So, is water jet cutting better than laser cutting? Neither is better than the other, but one tool may be more suited to your particular project than the other. If you have a complicated project with many parts that need to be cut, you may even end up employing both technologies at different times.
In general, lasers are a bit better for cutting thin metal very precisely and efficiently, while water jet cutting would be the choice for thicker projects that require cold cutting.
Your budget is also a major factor that could determine which method you choose. However, a qualified fabrication shop will be able to look at your project and needs and give you options along with their recommendation. All things being equal, lead time and cost may be the deciding factor of which technique you opt to use.
Finding the right partner
Impact Fab is the oldest water jet cutting shop in West Michigan. With multiple cutting tables, we have the capacity to expedite projects and accommodate our customers’ timelines. Whether it’s single-part prototyping or large production runs, we provide a wide range of water jet cutting services that are precise, cost-effective, and delivered on time. We operate a 13′ x 13′ and a 6′ x 13′ table, and offer both abrasive and pure water jet cutting.
Contact us to review your project, material, and cutting needs. We’ll work with you to provide the most efficient option to produce the unique parts you need to finish on time and on budget.