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CNC Waterjet vs. Plasma vs. Laser: The Pros and Cons Before You Buy

Submitted by mattk on Thu, 06/04/2020 - 15:33

The most commonly asked question regarding CNC cutting tables is “What type is the best?”. It’s a great question, and a very important question—but has many different answers. There are a lot of factors involved in choosing between a plasma table, waterjet table, and laser table. Capabilities, upfront cost, cost to operate, cutting precision and quality, production rate, and adaptability are all important considerations to make when deciding to purchase a CNC cutting machine. This guide will discuss the pros and cons of each machine based on the aspects that customers have found valuable in the past.

 

Upfront Cost

It is likely that one of the biggest factors when looking for a CNC cutting table is your budget. Your budget can determine a lot early in the selection process. The initial investment in CNC cutting machines vary drastically depending on size, speed, and cutting type. Cutting type being the biggest contributor to the price tag, CNA plasma cutting tables are by far carry the lowest upfront costs. Depending on its size and features, a plasma CNC cutting table can cost between 12,000 and $300,000. Since the technology has become cheaper to produce, the price has dropped significantly over the last 5 years. CNC waterjet cutting tables and CNC laser cutting tables both come in small, consumer-grade variants that should be avoided for commercial use. Their appeal is their price tag—consumer grade models can be as cheap as $1,000. If you are looking for a commercial waterjet table, expect to spend at least $100,000 on a reliable industrial model with high capacity. The steep price is due to the expensive ultra high pressure pumps required to cut metal with water. Finally, CNC Laser cutting tables are often the most expensive option. If purchased used, these machines will often cost upwards of $250,000. New laser machines start around $350,000 and can easily exceed $1,000,000. No matter your budget, it’s always wise to educate yourself on your options—the pros and cons of all three options.

 

Operating Costs

Our estimations of operation costs include the power, consumables, maintenance costs, etc. and does not include labor costs associated with operation. The labor costs, as well as any additional overhead required for your cutting operation should always be considered when purchasing new machinery. Plasma continues to be the cheapest among the three options, estimated around $16/hr to operate and maintain. The main source of this expense is from power usage and parts replacement—torch bodies, torch tips, electrodes, etc. Laser CNC tables can vary greatly in their operating costs due to 2 major factors. First, laser cutters come in two variants—CO2 and Fiber. Fiber lasers are quickly becoming the more popular option because they are virtually maintenance-free machines. Fiber machines are also proving to be cheaper to operate per hour than CO2 machines. The second factor is the kW output. This determines the capacity of the machine, as well as its cost to operate. Fiber CNC Laser tables can operate between $10-18/hr. CO2 CNC Laser tables can cost between $12-20/hr to operate. Waterjet is usually the most expensive to operate due to the need for consumable abrasives. Such abrasives cost around $0.25 /lb. Depending on the pump capacity and cutting depth, waterjet cutters cost between $20-40/hr to operate.

 

Production Rate

Cost per hour is only useful if production rate is included in the assessment. For instance, a project may take 2 hours on a laser cutter, but 8 hours on a waterjet. With that in mind, the total cost of making one piece may vary greatly. In these production speed evaluations we are assuming only the speed of cutting, not taking into account tooling changes. If considering a larger machine with multiple cutting tools, take into consideration tool change time and/or reset time. Plasma table cutters currently have the fastest cutting speed amongst the three options. Depending on material thickness, plasma can cut up to 200 ipm (inches per minute). Laser cutters and their technology are quickly competing with the cutting speeds of plasma cutters. CNC Fiber Laser tables are slightly faster than CO2 cutters on all thicknesses. The main factor in the speed of laser machines is the kW output and optics technology. Waterjet is by far the slowest of the three options when cutting thick material.

*Always consult a manufacturer’s recommended cut speeds for different metal types and thicknesses.

 

Precision

CNC cutting tables, by definition, are precise cutting tools. That being said, we are working with a low-margin difference between Laser, Waterjet, and Plasma in regards to precision. Precision, in this discussion, is the dimensions of the final product compared to the programmed design. Factors such as machine quality, kerf width (how wide a cut the cutting tool makes), and cutting design, affect the precision of all 3 machine types. Plasma is arguably the least precise due to the possibility of heat distortion as well as inevitable dross, or splatter, accumulation. Plasma cutters have an average kerf width of 0.150”— the biggest of the three machines, and works within a margin of error of +/-0.020”. Laser CNC cutters and Waterjet CNC cutters are very similar in their precision capabilities. Laser CNC tables have an average kerf width of 0.025” and operate within an error margin of +/-0.005”, an insignificant difference for most applications. Finally, waterjet CNC tables have an average kerf width of 0.035” and have the same error margin as laser tables, +/-0.005. When exploring your options, be sure to understand all the applications you will use your table for, and whether precision is a high priority.

 

Cut Quality

If you are even slightly familiar with these three types of CNC cutting tables, you will have an idea of the cut quality they produce. You can also guess from the information we’ve already discussed which machines may produce the cleanest final product. The quality is determined by the squareness of the cut, the amount of dross or splatter, and whether there is an edge bevel. The clear winner in regards to cut quality is the waterjet, which produces little to no heat. Waterjet tables produce no dross or slag, and creates a very square cut when your nozzle is clean. Laser tables do produce heat, but on thinner materials, not enough heat is generated to make a notable amount of dross. The edge created by laser is square and even; very comparable to that made by a waterjet. Plasma tables produce a lot of het on the material, thus creating dross and material splatter on the work piece. Plasma tables can also produce a beveled edge on harder or thicker materials. Keep in mind, more often than not, most pieces coming out of CNC cutting tables are finished further by sanding and grinding. Though the waterjet and laser tables can produce finished edges, it is normally recommended to sand the product further.

 

Conclusion

There are plenty of additional factors to take into consideration when choosing a CNC cutting table. There are also a few more options to choose from, each with their own set of upsides and downsides. This tool is meant to give you a quick understanding and comparison of the three more popular tables, and give you a basic understanding of how to approach buying a table. As always, we recommend that you compare specifications, reviews, and machine standards for any table you are interested in. It also never hurts to conduct more research around CNC cutting best practices and machine types. Elite Metal Tools has a variety of CNC tables from some of the best manufacturers in the industry. Do not hesitate to reach out to us with questions or inquiries about CNC cutting tables, or any machine that will improve your shop or business.