There are several processing options for sheet metal cutting, some factors to consider when evaluating suitability include: material type, material thickness, part geometry, desired edge quality, throughput, 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), waterjet, plasma, EDM and laser. Waterjet cutting was widely used in industry in the 1930s, while flame machining and plasma cutting made their debut in the 1960s. Laser cutting was introduced in the 1970s. The scissors cutting method is difficult to trace because some variations of it date back to ancient times. In 2016, laser cutting was the largest segment in global metal cutting machine sales. Comparing cutting processes provides insight into what attracts a large number of manufacturers to laser cutting sheet metal. Instead of listing the pros and cons of each procedure, here is a brief one-to-one comparison between cutting and alternative procedures.
shear cutting method
Divided into two main types: Shear cutting (such as stamping), where the entire geometry can be cut out of the sheet at one time by mechanical force; Contour cutting techniques, where the cutting source draws the geometry like a pen.
Punching and Laser Cutting
Punch cutting can be very fast as in many cases the entire geometry can be engraved with just one stroke. However, this requires significant upfront tooling costs, so production batches should be sufficiently large. The mechanical force used in punching may be limited by certain geometric features and punch cutting is not recommended for some shops working in agile environments.
The contour cutting process uses flexible tools to accommodate changing designs without fixed costs. As such, they create opportunities for manufacturers to do prototyping, short and mid-term production. Fiber lasers have paved the way for cheaper industrial lasers with high power. When one compares lasers to stamping, more cost-effective technologies and advances in automation are rapidly changing the way sheet metal parts are mass-produced. Many manufacturers already use laser cutting as a supplementary process to punch holes for mass production or to replace old punch machines with laser cutters.
shear cutting method
We discuss the main advantages and disadvantages of the profile cutting method, focusing on sheet metal cutting rather than sheet metal cutting, because the highest demand for cutting in the market is sheet metal. Note that thicknesses up to 0.5 inches (12 mm) are referred to as sheet metal, while thicknesses greater than 0.5 inches (12 mm) are referred to as sheet metal.
Waterjet and Laser Cutting
Waterjet cutting machines are versatile in cutting metals and non-metals. Fundamentally, waterjet is a machining process, so for harder materials, more cutting force is required, and the cutting speed will be slower. Cutting metal requires the use of abrasives in the waterjet, which can lead to nozzle wear, and management of accumulated abrasive piles as well as abrasive fines can be costly to operate.
Waterjet cutting offers flexibility in terms of the range and thickness of materials that can be cut. Fiber lasers can cut sheet metal faster, often with orders of magnitude narrower kerfs, and they require no maintenance or consumables, making them the production solution of choice if a shop does a lot of sheet metal cutting.
EDM and laser cutting
Manufacturers using EDM have at least one thing in common. They need to meet very tight dimensional tolerances (typically a few microns or less). EDM has filled the market need for cutting high-value parts larger than 12 mm in thick-walled metals that require vertical cross-sections and require ultra-fine tolerances and sub-micron surface finishes. The EDM process is inherently very slow, and since the EDM process works through a micro-arc between the thin wire and the metal, it cannot be cut too fast to avoid shorting the wire to the metal or tripping due to too strong an arc. Unlike laser cutting, cutting speeds cannot be increased significantly for thinner sheets. Thin parts can be stacked for batch EDM cutting to increase productivity, but pilot holes need to be pre-drilled in each part as a pre-processing step to begin EDM cutting. In that case, laser cutting can be a complementary process to pre-cutting holes and cutting features that don’t require micron-level precision. For the common sheet metal processing range (0.25 mm to 12 mm), laser cutting is much faster than EDM (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 to thick plates (a few millimeters or tens of millimeters), the kerf is usually wider than laser kerf, the heat input into the part is significantly higher, and the cut surface is rougher in some cases . Plasma cutting is generally considered a less accurate method of cutting sheet metal than lasers. Historically, the advantage of plasma cutting over laser cutting has been in cutting thicker plates and lower-cost cutting of less precise sheet metal parts. The rapid increase in fiber laser power at increasingly affordable prices is enabling more precise cutting of thick plates every year. For example, stainless steel, mild steel and aluminum up to 50mm thick can be cut with high quality and high speed using a 10-12 kW fiber laser system. It is foreseeable that in the future there will be even more movement between these two processes in favor of fiber lasers.
CO2 and Fiber Laser Cutting
In recent years, laser cutting of sheet metal has been dominated by fiber lasers. The main reasons include process reliability, higher cutting speed, ability to cut reflective metals such as copper and brass, maintenance-free, and lower cost of ownership.
Fiber laser systems have established their ability to cut metals with high quality and accommodate complex part geometries that have been challenging for other processes. However, when making the final decision to purchase a fiber laser cutting machine, customers often focus on other aspects specific to their situation, including whether a particular system can handle their part’s tolerances and compliance. It is economical to produce parts using specific fiber laser systems. Below we discuss these two issues at the highest level.
Can Fiber Lasers Handle Your Part's Tolerances?
Factors such as kerf size, taper, surface roughness, heat input to the process, and process variability over long production runs ultimately determine whether or not a part can actually be held within tight tolerances. The combination of small kerfs, low heat input, good surface finish and stable cuts make fiber lasers an excellent choice for cutting precision parts. Cutting accuracy depends in part on the kinematic system of the cutting machine. The IPG Laser Cube platform complements the inherent precision of fiber laser cutting with high-precision motion systems and advanced motion control features that enable features with tolerances as low as ±0.001 inches.
Is Fiber Laser Cutting Economical For Your Project?
The capital and running costs of the cutting process vary widely. Given their high speed and reliability, fiber lasers often lead other processes in terms of part cost. In addition, fiber lasers have been made into economical components that were previously unattainable. In the foreseeable future, the advantages of fiber laser cutting will be more obvious.