Custom Plastic Fabrication Advantages and Disadvantages
Orbital tube welding is known as possibly the purest, cleanest welding process, but the orbital welding process is also an economical choice for those requiring weldment perfection, as evidenced in a new article published by The Tube and Pipe Journal (a sister publication of The Fabricator).
The July 2020 article, titled, “Optimizing and economizing orbital welding for pipe projects: Getting around the conventional limitations of automated pipe welding processes,” features an interview with journeyperson Axenics welder, Tom Hammer, who details the capabilities and versatilities of orbital welding on metal tubing.
Orbital tube welding is used to solve a variety of technical challenges presented by Axenics customers, such as when it’s not practical or feasible to rotate a piece of metal tube or pipe for the welding process. The orbital welding process is also used for tight spaces that are not possible with other forms of welding.
Industries such as chemical manufacturing and alternative energy require the dispensing and transfer of gases and liquid chemicals with zero opportunity for contamination along the delivery journey. In such cases, Hammer prefers orbital welding on 316L stainless steel.
“That’s when it gets really delicate. We’re talking about welding on paper-thin metal. With manual welding, the slightest adjustment could ruin the weld. That’s why we like to use the orbital weld head, where we can dial in each section of the tube and get it perfect before we put the part in there. We tone the electricity down to a specific amount so we know when we put the part in there, it will be perfect. By hand, the variance is done by eye, and if we step on the pedal too much, it might blow right through the material,” Tom Hammer said in the Tube and Pipe Journal article.
How do you know if orbital welding is the right solution?
Hammer and the welding team at Axenics offer a “cheat sheet” or list of questions that helps them determine if your project would benefit from orbital tube welding as opposed to other tube-joining options. These questions take time and cost factors into consideration to offer you the best-possible quote:
- What type of tubing is already being used in the existing project? Does the material need to remain the same?
- What is the size and diameter of the tube to be welded?
- How many fittings are needed to complete the delivery system of tubing?
- How much space is required between weldments and tube fittings?
- What kind of tube finishing is needed?
- Does Axenics have the right head for the orbital welding machine in-house or will we need to purchase and/or have one designed?
- If the right head is not currently available, what is the cost to purchase the needed head or produce a custom head for the machine?
Industries that benefit from the orbital welding process
Ultra-clean welding is ideal for most industries, but there are certain ones which require:
- Zero contamination
- No less than 100% weld penetration
- Ultra-clean weld finishing
Alternative energy and chemical manufacturing were previously mentioned, but the semiconductor, medical device and life sciences commonly require high purity welds as well.
Orbital welding is generally used to provide the cleanest welds possible, significantly reducing a risk of micro contamination. Bacteria present in a delivery system is a significant problem for all of the industries mentioned above.
To ensure that welds have zero contamination, metal tubing weldments should be completed in a high-purity, particle-free environment, such as a cleanroom. Axenics’ Class 100 cleanroom is where the orbital welding process occurs, using a proprietary cleaning process.
We use 18 megaohms (MΩ) of deionized water to clean out each piece of tubing. Our welders wear cleanroom suits to prevent any contamination from getting into the tubes, and tools are cleaned before entering the space. We also flow argon through the inside of the tubing and through the welding torch to prevent oxidation from occurring.
Orbital weld testing is key for perfect welds
Hammer describes in detail the testing procedures and guidelines Axenics undertakes with orbital welding and other forms of welding in The Tube and Pipe Journal article:
“Every weld we do gets sight confirmation – full penetration testing. After that, the weld gets a helium spectrometer test,” he said. “Some welds get x-ray radiographic testing, depending on the code or customer requirements. Destructive testing is also an option.”
CNC tube bending
CNC tube bending is an effective solution for building various types of complex assemblies and an alternative to manual tube bending or welds or fittings.
Plastic bending happens when thermoplastic tubing is heated and its initial shape is altered with no need for cutting, welding or fittings. The result is a single piece of bent plastic tube featuring a variety of angles and/or number of bends. Plastic bending is a...