There are multiple processing options for sheet metal cutting, and some factors to consider when evaluating applicability include: material type, material thickness, part geometry, required edge quality, yield, allowable heat input or mechanical force levels, dimensional tolerances, capital costs, and operating costs.

The most popular traditional sheet metal technologies are shear cutting (such as stamping), water jet, plasma, EDM, and laser. In the 1930s, water jet cutting was widely used in the industrial field, while flame processing and plasma cutting made their debut in the 1960s. Laser cutting was introduced in the 1970s. The shear cutting method is difficult to trace because some of its changes can be traced back to ancient times. In 2016, laser cutting was the largest part of global metal cutting machine sales. Comparing cutting processes can reveal which factors have attracted a large number of manufacturers to use laser cutting of metal plates. Here, the pros and cons of each process are not listed, but a brief one-on-one comparison is made between the cutting and substitution processes.

Punching and laser cutting

Punching and cutting can be very fast because in many cases, the entire geometric shape can be carved with just one impact. However, this requires a significant upfront tooling cost, so the production batch should be large enough. The mechanical force used in punching may be limited by certain geometric features, and it is not recommended to perform punching and cutting in certain workshops working in agile environments.

Fiber lasers have paved the way for high-power industrial lasers to become cheaper. When people compare laser and stamping, more cost-effective technologies and advances in automation technology are rapidly changing the way sheet metal parts are produced in bulk. Many manufacturers have used laser cutting as a supplementary process for bulk production of holes or replaced old punching machines with metal laser cutting machines.

We discuss the main advantages and disadvantages of profile cutting methods, with a focus on sheet metal cutting rather than sheet cutting, as the highest demand for cutting in the market is sheet metal. Please note that those with a maximum thickness of 0.5 inches (12 millimeters) are referred to as sheet metal, while those with a thickness greater than 0.5 inches (12 millimeters) are referred to as sheet.

Water jet and laser cutting

Water cutting machines are widely used in cutting metals and non-metals. Fundamentally speaking, water jet cutting is a mechanical processing process, so for materials with higher hardness, greater cutting force is required and the cutting speed will slow down. Cutting metal requires the use of abrasive in the water jet, which may lead to nozzle wear. Managing the accumulated abrasive pile and abrasive powder also requires significant operating costs.

In terms of the range and thickness of materials that can be cut, water jet cutting has flexibility. Fiber lasers can cut metal sheets faster, usually with a narrow order of cuts, and they do not require maintenance or consumables. Therefore, if the workshop conducts a large amount of sheet metal cutting, it becomes the preferred production solution.

EDM and Laser Cutting

Manufacturers using EDM have at least one thing in common. They need to meet very strict dimensional tolerances (usually a few micrometers or less). EDM has met the market demand for cutting high-value parts with thick walled metal greater than 12mm, which require vertical cross-sections, ultra precision tolerances, and sub micron level surface finish. Unlike laser cutting, the cutting speed cannot be significantly improved for thinner sheets. Laser cutting can be a supplementary process of pre cutting holes and cutting features that do not require micrometer level accuracy. For ordinary sheet metal processing ranges (0.25mm to 12mm), laser cutting is much faster than electric discharge machining (even stacked versions) and can maintain high accuracy in many applications.

Plasma and laser cutting

Plasma cutting can be used to cut metal, from thin plates to thick plates (several millimeters or tens of millimeters), with slits typically wider than laser slits and significantly higher heat input into the parts, and in some cases, the cutting surface is rougher. Compared to laser, plasma cutting is often considered a less accurate method for cutting sheet metal. From a historical perspective, the advantages of plasma cutting over laser cutting lie in cutting thick plates and low-cost cutting of  precise sheet metal parts. Fiber laser power is rapidly increasing at increasingly affordable prices, making thick plate cutting more precise every year. For example, using a 10-12 kW fiber laser system can achieve high-quality and high-speed cutting of 50mm thick stainless steel, low-carbon steel, and aluminum. It can be foreseen that in the future, there will be even more movement between these two processing processes in the direction beneficial to fiber lasers.

The capital cost and operating cost of the cutting process vary greatly. Considering the high speed and reliability of fiber lasers, they are usually ahead of other processes in terms of component costs. In addition, fiber lasers have been made into economic components that were previously impossible to achieve. In the foreseeable future, the advantages of fiber laser cutting will become more apparent.

About HGTECH: HGTECH is the pioneer and leader of laser industrial application in China, and the authoritative provider of global laser processing solutions. We have comprehensively arranged laser intelligent machine, measurement and automation production lines, and smart factory construction to provide overall solutions for intelligent manufacturing.