High speed welding cameras for troubleshooting and R&D

Posted on by
Reply

High speed cameras enable humans to view welds in incredible detail because they capture and distill welding phenomena like droplet detachment and defect formation.

The Canadian Centre for Welding and Joining offers a great online selection of videos made with two models of Phantom camera. For example, see this mesmerizing video of GMAW of steel showing globular transfer captured at 3000fps.

While high speed cameras produce amazing images of welding, they generate huge amounts of data. The practical data limit results in a tradeoff between resolution and frame rate. The higher the frames-per-second, the lower the resolution and vice versa. Also keep in mind that higher speeds mean shorter weld durations – you might only get to record 2 seconds of welding at the highest speed.

Most high speed cameras will let you select where along the frame rate vs. resolution continuum you wish to record. For example, this video of MIG welding was made with a Photron camera at 10,000 fps and 640×744 pixels resolution.

When it comes to high speed, how fast is fast enough? It’s possible to record welds at 10,000+ or even 100,000+ fps, but for most applications, 1000-2000 frames per second will allow you to view welds in sufficient detail for process parameter development or troubleshooting purposes.

If you are looking for a welding camera that captures video at higher than standard analog speeds, feel free to contact us for free advice on selecting a camera system and determining the appropriate frame rate and resolution for your application.

The frames per second question

Posted on by
Reply

MeltView welding cameras record video at standard film and television speeds (25 fps in PAL and 29.97 fps in NTSC). It’s possible to capture video at higher frequencies, but is it worth it? That depends on whether you are watching welding in real-time or recording it for playback.

For real-time monitoring, the key question is, what is the top frame rate that the human visual system can perceive? For recording and playback, the key question is, how fast are the welding events that you want to observe happening?

We’ll consider live monitoring of welding in this post and recording and playback of welding in the next post.

According to Peter Jackson, when filming The Hobbit, his crew wanted to create a “more lifelike and comfortable viewing experience” by increasing the fps above the standard 24. He reports that they “tested both 48 fps and 60 fps. The difference between those speeds is almost impossible to detect, but the increase in quality over 24 fps is significant.” So they opted for 48 fps.

If you didn’t get to watch The Hobbit in 48 fps, this app will help you to compare the difference that frame rate makes in viewing experience.
fps
First slow the balls down to 50 px/s.
Notice the background – it does appear more lifelike at 48 fps than 24 fps.
Set one ball at 30 fps and the other at 60fps. Then begin to increase their speeds simultaneously to 100, then 200, then 500, etc.
You can also try setting the two balls at two different speeds to simulate a slower moving object (e.g. the torch) and a faster moving object (e.g. the molten metal).

For live monitoring of welding, does 48 or 60 fps offer an advantage over 25 or 30 fps? Possibly a slight advantage in clarity, which may be noticeable for fast-moving processes such as GMAW or LBW (represented by speeds between 100-500 px/s in the simulation; note that at speeds of px/s <100 and >500, it’s hard to see any difference between 30 fps and 60 fps).

Perhaps more interesting to consider is what you can observe when you capture video at very high speeds, in the thousands of frames per second, e.g. for troubleshooting purposes. High speed imaging of welding is next.

Cameras for maintenance and repair welding in process and energy plants

Posted on by
Reply

Power and process companies have considerable motivation to extend the useful life of their facilities through preventative repair. Typically the cost of repairs is significantly less than that of new components, and scheduled maintenance has far less negative impact on profitability and reputation than unscheduled plant shutdowns. In the energy industry, periodic maintenance and repairs include:

  • Coating of gas and steam turbine parts with thermal spraying technologies.
  • Rebuilding of turbine blades using laser based direct deposition technologies.
  • Overlay welding of large evaporator wall areas in boilers using mechanized equipment.

MRO engineers seek methods that reduce overall downtime whilst ensuring the safety and reliability of parts. Tasks and tools include:

  • Identifying repair needs in a fast and accurate manner.
  • Simulating, scheduling and specifying the repair process.
  • Tools for carrying out the repair work in a timely and accurate manner.
  • Tools to ensure that the repaired components meet or exceed specifications.

MeltView DART-A and DART-X welding cameras, mounted to mechanized welding heads, can improve the speed and accuracy of repair welding. Repairs are often carried out in-situ, and cameras can reduce the need for supporting infrastructure (such as scaffolding) and make the operator’s task easier by providing magnified vision in inaccessible areas. One or two video cameras may be mounted to the welding head to observe the leading and/or trailing edges of the weld pool as well as wire and background. The MeltView DART cameras have integrated lighting and automatically switch between welding and non-welding states to provide a clear image in both conditions.

Monitor Micro Welding with MeltView 100

Posted on by
Reply

The weld torch and weld joints found in mechanized micro TIG and micro plasma welding stations are – as the name implies – small. Both the fine scale of these processes and the bright light emanating from the GTA or PAW torch present challenging conditions for operators who need to see what is going on.

Micro TIG or micro plasma welding stations often utilize microscopes to setup and monitor the process. Before starting the welding process, the operator will typically use the microscope to set up the part and then position a suitably shaded welder’s lens in front of his eyes. His hands are left free to make any necessary positional adjustments. Some micro welding machines are designed so that the operator does not need to observe the process except for the initial set-up. Such machines may use a dedicated industrial camera for this purpose. For machine applications where the operator is required to make in-process adjustments to torch position or welding parameters, such cameras are not suitable as they are incapable of providing a meaningful image of the thin seam during welding.

The MeltView 100, equipped with suitable lenses for micro welding, can be used to provide real-time monitoring solution for micro welding. A welding camera solution may lead to improved quality, reduced re-work (higher output, lower costs), and reduced set-up time. The operator doesn’t need to orient himself to a microscope or position and adjust a protective lens, and the ease of observing a magnified image of the weld on a monitor reduces operator stress and fatigue.

Improve set-up and processing bore cladding with MeltView CORE

Posted on by
Reply

Cladding or overlaying a nickel-based alloy on top of a steel substrate is a method often employed in the Oil and Gas industry to protect the underlying component from corrosive fluids. It’s critical that the cladding is applied continuously and evenly. Defects in the alloy layer defeat the purpose of cladding and result in costly scrap, re-work or even failure of the component in the field. The overlay process is often inaccessible to humans, and welding cameras can enable effective and cost-effective monitoring of this critical process.

The MeltView CORE camera is designed for monitoring horizontal bore cladding operations where a TIG torch is extended deep within a valve or Christmas tree. Typically such applications have high ambient temperatures due to preheating and long operation times. Both factors stress and fatigue the operator. The MeltView CORE can reduce the operator’s exposure to such hazards and improve working conditions.

The MeltView CORE is mounted on the torch arm so that it is located external to high temperature environments, reducing the need for camera cooling. The operator can view a magnified, clear image of the TIG torch and weld pool at the operation station for monitoring purposes. The motorized zoom, focus and iris may be controlled from the station such that the lens settings may be optimized whenever desired.

Presenting the MeltView DART-X

Posted on by
Reply

The MeltView DART-X welding camera delivers the same clear image quality as the MeltView 100 in a housing designed to withstand the intense heat and vapor/spatter of a welding environment. The combination of gas knife, easily replaceable spatter shields, water cooling and integrated lighting makes it the perfect visual monitoring solution for monitoring automated processes that have a high ambient temperature such as pulsed MIG cladding of pressure vessels, pipe welding, electrogas welding and internal pipe cladding.

DARTX-WEB

The camera automatically switches between arc-on and arc-off modes and is designed for working distances (between lens and melt pool) of 4-12″ (100-300mm). The analog output from camera feeds directly into a monitor .

Sample videos of different welding processes visualized by the MeltView DART are available at www.melttools.com.

MeltTools also supplies a range of accessories such as camera mounts, cable jackets, supply hoses and monitors for use with MeltView cameras such as the MeltView DART.

Sensing Changes in Automated Welding

Posted on by
Reply

Please follow the below link to the current digital edition of ‘The Fabricator’ where you will find our latest article ‘Sensing Changes in Automated Welding‘. This article, written with Stephen Thacker from MetaVision, covers the application of four different types of vision systems employed in automated welding

  1. laser triangulation
  2. machine vision
  3. welding cameras
  4. thermography

 

Cameras that help to monitor fusion welding processes

Posted on by
Reply

Below is our article from the current edition of the Tube & Pipe Technology magazine. 

MeltTools LLC has developed a range of cameras for cost-effective visual monitoring of fusion welding processes. MeltView cameras automatically adjust to immense changes in light to provide a clear image before, during and after welding. The cameras are ruggedized against the welding environment and customized to fit automated and mechanized welding applications such as internal pipe cladding and tube/pipe welding.

Rework and scrap rates have a significant impact on profit margins, and a clear image of the melt pool enables the operator to detect product flaws in real-time and correct processing errors. Other benefits of real-time visualization include faster and more accurate set up of welds, reduced operator stress/fatigue and shared process monitoring among operators, managers, and quality assurance team. Quality assurance may become integrated into production during in-process inspections, and visual records may be combined with process signal data as part of a product traceability program that enhances the manufacturer’s reputation.

With today’s sophisticated tube and pipe welding machines, a clear view of the melt pool is often difficult to obtain. It may be obscured by clamps, joint geometry, multiple torches, wire-feeders, sensors (including seam trackers and bead profilers) and shielding devices. To meet this challenge, MeltView cameras are designed to fit into various work envelopes. In addition, many welding processes are hazardous due to high temperatures, trapping hazards and awkward positions (e.g. great or small heights), and a visual monitoring solution is essential for safe and accurate operation. MeltTools is committed to reducing the barriers to integrating visual-monitoring systems into today’s welding equipment.

MeltView cameras feature integrated gas- or water-cooling for long-life and reliable function as well as an optional integrated gas-knife and replaceable spatter-guard to maintain a clear optical pathway under conditions of high spatter/vapour. MeltView cameras are also available with integrated LED lighting. The video output is in convenient analogue format, which may be fed directly into a monitor for a simple and easy-to-maintain visualization system or may be converted to a digital record for process analysis and/or record keeping.