What is the Difference Between Drag Knife and Tangential Knife Cutting Technology?

It seems that Roll-fed cutter technology is everywhere these days. If you’re not hearing about the speed, precision, and performance of the latest models at trade shows or in magazines, you’re certainly seeing the results of these cutters in the form of ads, signage and store windows at businesses and on fleet vehicles the world over.

Here we’ll discuss the two main types of cutting systems that drive roll-fed cutter and plotter technology so you can apply the best performing and most cost-effective system to your finishing and cutting operation.

How Does Drag Knife Technology Work?

Summa Drag Knife Cutting Head

Drag knife (or swivel knife) technology is the type of cutting technology used in the newer Summa S One Series, as well as the Summa S2 D Series.

Drag knives are designed to spin freely on their vertical axis, allowing the blade to cut while being pulled across the substrate by the cutting head, while the media is simultaneously moving forward and backward via contact with the pinch rollers. This synchronization of both cutting head and media creates fast, efficient cutting while keeping the drag head positioned accurately for the next cut as the knife scrolls and rotates about its vertical axis.

Drag knife cutting heads don’t have the capability for vertical movement in and out of the substrate.

Without the ability to lift above the cut material, as highlighted on step 3 on the above graphic, the drag knife leaves a very small imperfection at the location of any corner. For most artwork, this imperfection is minor and easy to cut cleanly while weeding.

How Does the Drag Knife Respond to Media?

Drag knife cutters are exceptional for cutting most thin to medium thickness media types like cast and calendered vinyl, laminated vinyl, digital print media, rigid sandblast foils, or even flock and flex materials. Multiple blade types are available for both the Summa S2 Series as well as the S One series of drag knife cutters, increasing these machines’ abilities to cut additional media types substantially.

"Drag knife cutters are exceptional for cutting most thin to medium thickness media types like cast and calendered vinyl, laminated vinyl, digital print media, rigid sandblast foils, or even flock and flex materials."

Additionally, the S One is getting strong reviews as an excellent system for cutting window tint and paint protection films for the automotive after-market industry

What are the Advanatages of Drag Knife Cutters?

While drag knife technology has some limitations, it is the most widely used roll-fed cutting technology in the world. The recently discontinued SummaCut Series is one of the most popular series of vinyl cutters ever built. The recently launched S One builds on that success with a multitude of technical, performance and operator experience improvements.

The Summa S One Series unites power and precision with an efficient and affordable high-speed drag knife cutting head that allows for quick switches between blades, thick material blades, plotting pens or pouncing tools. Combining intelligent and easy-to-use features with up to 600 grams of cutting force, the S One™ Series outperforms many manufacturers' high-end cutters

Learn more about the Summa S One Drag Knife Cutter here:
Summa S One Series Vinyl Cutters

Learn more about the Summa S2 D Series Drag Knife Cutter here:
Summa S2 D Series Vinyl Cutters

How Does Tangential Knife Technology Work?

Summa Tangential Knife Cutting Head

Instead of a freely rotating knife, the tangential knife is fully controlled by a motor, allowing for more cut downforce. This external motor extends and retracts the knife into and out of the media at high speeds, while positioning the knife in the correct orientation for the next cut path. Whereas the drag knife remains in the media during the entire cut, tangential cutter technology lifts the knife from the media, rotates it and lowers it back into the media at critical places like tight angles and corners creating a slight “overcut” for easy weeding.

When it comes to cut-quality, nothing can emulate genuine tangential cutting. Graphics weed easier. Thick materials slice better. Intricate designs cut with pinpoint accuracy.

How Does the Tangential Knife Respond to Media?

Without the drag forces that influence the knife’s trajectory, tangential technology allows for much higher cutting pressures and enables the use of longer knives and blades compared to drag knife technology. As a result, the user will be able to cut thicker and harder substrates with exceptional detail and quality. This technology is common on flatbed cutting machines, used to cut thick substrates. To achieve a high-quality cut in applications such as floor graphics, vehicle graphics, textile, sandblast, and safety signs, we highly recommend the additional investment in tangential knife technology.

Summa and Tangential Knife Technology

The Summa S2 T Series utilizes industry-leading Tangential Knife Technology. Despite all the state-of-the-art features, S2 T Series cutters remain remarkably easy to use. A vibrant, full-color LCD touch-screen featuring an upgraded graphic user interface and intuitively reorganized menu system allows the user to conveniently control every function and parameter.

By combining the world's most sophisticated cutting technology with legendary Summa tracking, S2 T Series vinyl cutters are truly in a class by themselves. Three high-power digital servomotors drive even the most demanding materials with unsurpassed performance. Summa's patented MicroSprocket™ drive drum technology provides precision media handling and remarkable repeatability on every job, from start to finish.

Learn more about the Summa S2 T Series Tangential Knife Cutter here:
Summa S2 T Series Vinyl Cutters

What are the Advantages of Tangential Knife Cutters?

"The Tangential technology's depth control also allows you to both die cut and kiss cut vinyl during the same job."

Aside from cutting speed and the ability to use thicker blades, another advantage of Summa knife technology is accuracy of depth control. Operators can set cutting depth as deep or shallow as they like, depending on project, material and substrate thickness. The Tangential technology's depth control also allows you to both die cut and kiss cut vinyl during the same job.

A further notable advantage is the cutter’s abilities to cut corners, angles, and intricate artwork. As every corner is overcut slightly, weeding intricate designs is much more efficient, even while cutting meticulous detail in thicker or laminated material.

TL;DR Summary

Drag knife blades cut by being pulled across the media, with no ability to raise or lower into the substrate. Drag knife cutters are exceptional for cutting most thin to medium thickness media types like vinyl, digital print media and tint. They are generally a more inexpensive roll-fed cutting technology compared to Tangential knife cutters.

Tangential knife cutters have a separate motor in the cutting head that raises, lowers, and controls the direction of the blade along the cut path. Tangential knife performance is better for detailed cutting, precise corners, and thicker materials where longer blades may be required. Generally speaking, tangential cutters are more precise, more powerful, and are generally considered to be a higher performing system over drag knife cutters.

Learn more about our latest vinyl cutter promos on our Deals and Promos page.

Vinyl cutters