Time to Cut the Old Technology Loose

With its 14-year-old machine no longer meeting its needs, ButlerBuilt looked for a change in 2007. Butler and Ashleman considered two options: upgrade the existing plasma cutting system or purchase a new system.

The manufacturer of the original plasma power supply was in the process of discontinuing all support on the plasma system ButlerBuilt purchased in 1993. Additionally, the drive carriage on the plasma cutting system had an outdated rail design, and the drive capabilities were considerably less than newer machines on the market. An upgrade would cost almost as much as a new machine.

The decision was made to purchase a new machine, and Ashleman began an intensive process to research the best systems to meet their needs.

"Our first plasma system gave us good service for almost 15 years, but we chose to refresh with a new machine, new warranty, and new technology," Butler said.

All About the Accuracy
After mapping out ButlerBuilt's specifications and thoroughly researching several plasma systems, Ashleman determined the final decision on a machine would be based on three factors: part repeatability, tolerance of a finished piece over the life of a consumable, and optimal cutting speed.

"With our old system, as the consumable life grew, so did the part tolerance," he said."It was something we were trying to minimize, and it worked out great to find the machine that would do it for us."

ButlerBuilt selected a Genstar cutting table and a KALIBURN Spirit 150a plasma cutting power source from Westwood Robotic Technologies in Elizabethtown, N.C., in the spring of 2007.

The Spirit150a is a 150-amp machine, which gives the seat fabricator the power to maintain repeatability over the consumable's life span. The power source is more than double the size of the company's previous 70-amp system.

The new plasma cutter also gives ButlerBuilt the capability to cut materials up to 1-inch-thick plate, if necessary, and ¾-in. plate on a daily basis.

The majority of our production is 0.090-inch through 3⁄16-inch aluminum, but we were maxed out at high-tolerance cutting of ¼-inch pieces. Now we can quality-cut as much as an inch thick if we need to," Ashleman said.

ButlerBuilt's 150-amp system delivers the speed and cut quality it needs for a majority of the aluminum it cuts. But it also provides the strength necessary to mimic the same results on harder aluminum alloys, which can be comparable to cutting carbon steel.

Using plasma arc cutting to clean-cut stainless steel sheet and plate

To cut stainless steels and other metals with plasma successfully, fabricators need the following tools:
To clean-cut stainless steel sheet and plate, fabricators first must choose the right CNC cutting equipment and then set the correct process-related variables. Precise machine motion controls, torch-to-material distance control, and the correct plasma and assist gases all are crucial to producing weld-ready plasma-cut edges on all stainless steel thicknesses.

1. Precision machine motion controls
2. A smooth linear drive system
3. Software controls that automatically compensate and provide proper speed and acceleration and deceleration for various part features

During the plasma cutting process, material is in the molten state inside the kerf zone. Mechanical problems such as motion irregularities cause vibrations, which transfer through the machine axis into the cut edge. These vibrations are solidified into the cut surface and can be easily mistaken for process problems. These motion irregularities and/or vibrations cause a rough-cut surface, nonlinear cut edges, and overall poor cut quality.

Plasma Cutting Machine

To initiate the cutting process, a pneumatic probe locates the material position and provides an accurate and repeatable pierce height. After the pierce is made, the plasma arc cutting (PAC) voltage from the plasma power unit is used in a closed-loop process control system to maintain torch-to-material height while cutting.

Automatic voltage control precisely maintains the torch tip-to-material distance. This is vital when processing thin sheet and stainless steel plate.

Fabricators can process stainless steel with clean-cut surfaces by using nitrogen or a blend of oxygen and nitrogen as a plasma gas. These plasma gases provide a nonoxidizing plasma arc, which produces a clean-cut edge that is weld-ready without secondary operations.

Nitrogen also increases electrode life by preventing oxide formation on the tip of the halfnium electrode. Halfnium is used as the metallic element in the electrode, which also is compatible with oxygen as a plasma gas for steel cutting.

Pure oxygen is not recommended as a plasma gas for stainless steel cutting because of its oxidizing characteristics, which leave an oxidized, contaminated cut edge.
Compressed air is not used for cutting because it often is contaminated with water, oil, or other contaminants. These contaminants can cause regulator and solenoid valve breakdown, as well as plasma double-arcing.

The type of stainless steel assist gas (or shield gas) to use varies according to the material thickness and the desired cleanliness of the cut edge. Based on each assist gas type and the material thickness, different conditions and chemical reactions result.

CNC laser cutting Machine overview

CNC laser cutting Machine overview
We cut a metal sheet through intense laser beams to generate different shape or to fulfill different functions. The total procedure is done through a machine termed as CNC laser Cutting Machine, which runs on a CNC method in CNC machine shop. CNC is computer numerical control and most of the manufacturing machines run on this technology. CNC has brought a revolution in the industry through this application as various machines are based on this method.

Laser cutting

In laser cutting procedure, a beam of high density light energy is focused through a tiny hole of nozzle and when this laser beam strikes the surface of work piece, the material of the work piece is vaporized. CNC laser cutting process has become popular in the industry, owing to its capability of cutting simple to intricate designs accurately. This is the reason why it is used widely for many applications like architectural, aerospace, electronic, medical, automotive, power generation, biomedical, decorative, petrochemical and so on. Several products that are manufactured through plasma cutting procedure includes brackets, gaskets, cams and assorted mechanisms. The website www.emachineshop.com offers the best comprehensive details regarding the CNC laser cutting machine.

Laser cutting offer low cost for prototypes as physical tooling is not required. The heat distortion is very less and is restricted to 10% of material. This proves much effective in comparison to other sheet cutting procedure available in the market. The advantages provided by laser cutting include less of burrs, maintaining close tolerance, and can be performed on large range of materials. Laser cutting procedure works best on materials like stainless steel, carbon, nylon, wood, plywood, aluminum, polythene, derlin, acrylic and galvanized steel. It is difficult to cut metals like aluminium and copper alloys as they reflect laser light as well as absorb and conduct heat. . Unlike other sheet cutter technique, a software programming is also required to run the laser cutting machine and along with it operator check service needs to install to protect from error.

The material produced possesses a smooth edge and edge quality is usually very good for thin materials - around 1/16" or less. This procedure has helped the manufacturing sector immensely as variety of products can be made at the same time. This has helped in the advancement of industry sector. Various CNC machine shops now also use CNC laser cutting machine for their production along with water jet cutting and CNC machines.

Technology Gives A Cutting Edge in Cutting Sheet and Plate Metals

Technological advances in the field of manufacturing are what companies use to gain and maintain a cutting edge over their competition. Thirty years ago no one would believe the technologies of James Bond and Star Wars would find their way to the metal fabricator's shop floor; but they have. Two innovative alternatives to burning or oxidizing sheet and plate steel are :

- Laser Cutting of steel
- Plasma Cutting of steel

Laser technology gained much ground in the 1980's through Defense Department research. The Strategic Defense Initiative (SDI) paved the way for today's advanced commercial applications of laser use.

Plasma cutting machine

Laser is a word derived from Light Amplification by Stimulated Emission of Radiation. It involves the use of an electronic optical device. In the case of steel, output from the device, the laser beam, targets an area of the sheet or plate. This laser stream receives its direction from a computer, which pinpoints the area requiring the cut.

Cutting steel with a laser-cutting machine offers an accurate clean cut. Many other materials benefit from this process, such as wood, copper and exotic alloys. Sheet and plate steel receive cuts of close tolerance, much faster than traditional cutting methods. Laser cutting machines are capable of cutting steel up to one inch thick. These machines can perform these accurate cuts repeatedly and with high consistency.

With laser cutting, the cut edges of the steel are clean. This leaves a cut edge with a nice surface finish. This type of cutting allows for less warping of steel; as the zone affected by the heat is small. Laser applications mean less physical contact with the sheet or plate steel. This means less wear on the steel being cut and less chance of a poor quality cut.

Another great advantage of laser cutting of steel is that there is no wear on the laser. This is an advantage over mechanical cutting tools, which undergo stress and wear in the cutting process. If proper maintenance is performed on the optical mirrors used to reflect the laser beam to its target, many months of use are possible before they must be replaced; unlike standard tooling.

Plasma cutting machines utilize a different process. A plasma cutter or torch uses inert gas or compressed air. It uses pressurized nitrogen, argon, or oxygen. Today the use of compressed air is more common.