Eckert CNC machines using plasma technology, are not only precise, fast and efficient when cutting conductive materials such as carbon steel, stainless steel or aluminum. They also offer the possibility of plasma marking using the same torch, which greatly improves the work when drawing lines or applying alphanumeric symbols.

We decided to conduct a small experiment and check, what the quality of marking depends on, when working on the same material samples. We used S235 structural steel with a thickness of 15mm. In making four different samples, we used different gases used to carry out the cutting process, such as Argon and Nitrogen, to see how the quality of the symbols made would change depending on the gas used. We also used different sets of parts, designed for different amperage, as another variable in the machining process.

Plasma marking: fast, precise, fully automated

Marking, in a general sense, involves marking out lines and symbols on the surface of the material to be machined, with these lines intended, among other things, to assist in the further processing of the material in question. Marking using a numerically controlled torch on a CNC machine has obvious technological advantages over other, such as manual marking methods.

First of all, it guarantees precision, the gouges are accurate and legible, and their depth can be controlled.  It is worth mentioning, that automated scribing from traditional detail marking is more permanent and is not washed out or blurred in further machining processes. It's also speed of execution and economic efficiency. Workpieces can be scribed immediately during the machining process, and a set of consumable parts is worn to a minimum.

Marking quality and the use of different plasma gases: Nitrogen and Argon

Plasma cutting technology uses a variety of gases, such as Argon, Nitrogen, Hydrogen, but due to their different physical properties, mixtures of them work best. The selection of the right gas is, of course, determined by factors such as the type of material and the depth of the line, that we want to make in the material to be fired. 

How does the choice of gas affect the quality of marking? We prepared the first two samples on a set of parts designed for 170A, where the target intensity was 15A. The main variable, however, was the type of gas. It was observed that, under these experimental conditions, the sample prepared using Argon had slightly better quality than that obtained using Nitrogen.

Change of parts and lower amperage

First, we changed the set of parts to those designed for lower amperage (up to 50 A), resulting in a narrower plasma jet. Amperage is one of the key parameters in plasma cutting technology that affects machining results. Higher amperage allows higher cutting speed and depth, but requires a larger diameter nozzle, which leads to a wider plasma jet.

How does this affect marking, that is, the application of lines to the surface of the sample? For the lower amperage part, we used two different gases: nitrogen and argon. The first sample was made with nitrogen at 15A, while the last sample was made with argon at 9A.

As a result, we obtained four samples cut from S235 carbon steel with a thickness of 15 mm. All the samples were also plasma cut at 170A and the results were compared. The last sample, made with argon gas and the lowest current of 9A, had the best scribing quality. This sample received the highest score on our scoring scale.

In our experiment, we tested the effect of gas type and current intensity on the quality of routing. As a result, we obtained samples of varying quality, which confirms how many factors affect the marking and cutting process in CNC machine plasma technology.

Plasma cutting technology with CNC machines is characterized by a number of variables that affect both the cutting and marking process. In our experiment, we focused on studying the effects of plasma gas type and current intensity on the quality of marking, obtaining four different samples.

The quality of plasma marking depends on many factors, such as:

• the type and quality of material,
• quality and level of wear of operating parts,
• type of aggregate,
• type and quality of gases,
• scribing speed,
• current intensity.

However, the Eckert machine operator does not have to worry about the perfect selection of all parameters. Eckert machines are equipped with a database of predefined parameters that have been optimized and tested. As a result, the element of operator error is greatly reduced, guaranteeing the best possible routing quality.

The predefined parameters on Eckert machines are the result of years of research and experience. Which makes, that operators can focus on other aspects of their work, confident that the quality of routing will be at the highest level.