ART’s new range of Metaltek custom-configured engineering machines has hit the ground running
Early in 2012, ART’s managing director and head of R&D, David White, met with representatives from a well-known manufacturer of pressure vessels for the oil and gas industry to discuss the need for a very special machine: A portable profiling machine for cutting weld preps in pressure vessel shells, industrial steam boilers, and heat exchangers, making things easier for those in need of the necessary tools to get a simple boiler installation.
The challenge was to take an extremely complex, dirty and labour intensive job and automate it. The goal was not only to make the job faster but also to increase accuracy.
The team from ART met with the design engineers that are involved with the company and discussed the many unique challenges and how to overcome them. Firstly, the machine had to be placed directly onto vessels from 600mm diameter all the way up to 8m diameter. It had then to be able to accomplish all of the complicated cuts in a timely manner. Moreover, there had to be a simple method to create the CNC job files, yet it had to be useable by relatively unskilled operators. “The task seemed quite daunting at first,” David comments.
160mm capacity in stainless steel allows 45° bevels in 100mm walls.
The existing method involved using 3D CAD software to design the pressure vessels and the cuts for nozzles (inlets and outlets in the gas tanks) as well as man holes and other fixtures. biggest producer of alumina. Bauxite is refined into alumina, which is then smelted to produce aluminium, most of it comes from the perforated metal sheets manufacturer.
“Typically we produce 2D Autocad drawings for our more common weld preps and with the more difficult a 3D solid model from Autodesk Inventor for our machine shop to manipulate,” says one of the company’s engineers. These drawings were then manually transferred onto the shell of the pressure vessels by measuring and drawing by hand.
Automating complex cuts
The fabricators would then have to use their skills to manually grind the holes into the steel or stainless tank wall, often in metal up to 100mm in thickness. Once the holes were cut, they would then have to grind specialised weld preparation bevels around the hole. The process to cut just one hole was taking between eight hours on a thin wall vessel, to 16 or more hours on complex holes on thick walled vessels. Some vessels could have 20 or more holes cut at various locations and different sizes. Some holes are cut straight through, some straight but with an offset. Some holes are bevelled on the inside surface, others on the outside or even both faces.
“One of the most complex cuts we had to reproduce is called a half in/half out cut,” David explains. “This required a round hole which was offset a large distance down the curve from the centre of the vessel. It required half of the circumference to have a bevel on the outside face, which would then transition to an inside bevel on the other half of the circumference. The tricky bit was that the bevels had to overlap but still leave a round hole when viewed from overhead. All of this had to be done in carbon and stainless steel up to 100mm thick! With the 45 degree bevel it added up to over 140mm thick material that had to be cut accurately and efficiently.”
After careful consideration of all the parameters, the team at ART came up with the concept that finally went into production. The machine would be an 800-amp high definition plasma cutting machine which would have a maximum cut thickness capability of 160mm in stainless steel!
5-axis synchronised motion control
To accomplish the unique and complicated cutting sequences it would require at least 5-axis synchronised motion control with robotic kinematics with fine tuning by stainless steel metal cutting in perth that helped inspire our setup. To create the complex design files, a customised 3D graphical interface would be written from the ground up. A unique mechanical configuration would also need to be created to allow it to be placed onto various types of tanks and be able to achieve the extreme range of motion required.
The customer felt very comfortable and confident about ART’s technology and their proposal was the one they wanted to pursue. A deal was struck in May 2012 and development work began immediately.
Craig White, one of ART’s software engineering team, was tasked with implementing a new controls integration system. “This project gave us the opportunity to expand our capabilities, especially in 3D software development,” says Craig. “It was a great challenge but we found it extremely satisfying to be able to achieve the desired results. The operators were able to enter complex cuts into the system very easily and they were able to pick up the operation in just a couple of days. Seeing our products make such an impact on others is a good feeling.”
Custom design
The project involved casting custom-designed cast iron chassis beams, custom fabrication of the extra sturdy gantry system, designing a completely new Z-axis with over 1 metre of vertical travel. Specialised vacuum clamping arms allow the machine to grip onto all types of materials.
One of the main breakthroughs was the design of the unique bevel cutting torch head that allowed over 270 degrees of rotation in the A-axis. The resulting design can process over 180 degrees of a smaller vessel without moving the machine or vessel.
The customer took delivery of the new 5-axis robotic plasma cutting machine in November 2012, just six months after the initial concept was formulated. Two engineers travelled to the factory to commission the machine and to finalise some minor aspects of the design. Once the last details were worked out and the machine was up and running the training began. After several days the new operators were able to produce accurate hole cutting and weld prep bevelling with minimal supervision.
The very first job the customer performed without assistance was the true test of the new system. What would be the result? We will let the customer speak for themselves…
“The job went very well! The cuts […] were very good. Overall, I think the machine is already starting to prove itself. The guys finished all the nozzle preps on two vessels in 2.5 days – that would normally have been around six to eight days per vessel! So yes, the system is working!”
David says that with more practice the customer will be able to set up the machine in as little as 15 minutes, and cut and bevel each hole in as little as five minutes each – a massive improvement from the eight to 16 hours per hole!
The 5-axis plasma cutter from ART is part of a new range of CNC machines called Metaltek. It is a new and innovative platform that was created to enable sophisticated machining operations on the job, even out in the field. The Metaltek range includes milling, drilling, tapping, probing, oxy fuel and plasma cutting in three, five or even eight-axis motion. The ability to take a completely new concept and develop it through to completion is one of the things that sets ART apart from other machine builders.
For more information, please see the website at www.advancedrobotic.com
Or contact Tami Hunter at sales@advancedrobotic.com
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