Lenses with thinking power

© TRUMPF

3D scanner optics work autonomously. Welding optics control the temperature of the plastic melting process, and fixed optics monitor the state of the process. In Industry 4.0, optics have their own minds, too.

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f smart factories are ever to become the norm, machinery and machine components need to be capable of registering and acting on much more information. TRUMPF took this insight to heart and is now applying it to optics as well. Customers don’t have to wait for smart factories to start enjoying tangible benefits from this. They are already benefiting from easier processing, better results, more flexible application and increased durability of components.

Intelligent 3D scanner optics

Scanner welding

Scanner welding enables highly productive and flexible production line layouts, making welding in series production faster, more accurate, and thus more cost-effective. In scanner welding, the beam guidance is done using mobile mirrors. The beam is guided by changing the angles of the mirrors. During welding, the scanner optics can also be guided over a workpiece in conjunction with a robot. This “flying” movement is what inspired the term “welding on the fly”: the robot and the scanner optic synchronize their movements in real time. The use of a robot increases the workspace significantly, permitting true three-dimensional part processing.

The new I-PFO is optimized for use on industrial robots. It is especially useful for on-the-fly processing of larger workpieces. The robot arm guides the flange-mounted optics over the workpiece in one fluid movement. In this process, the arm does not need to travel to exact positions – it just needs to bring target areas into the working range of the I-PFO scanner optics. The scanner begins processing autonomously as soon as the relevant area comes into range, whenever this is in line with stipulated process parameters.

The robot and the I-PFO work smoothly together because the optics, robot and workpiece all use the same coordinate system. As the robot moves, it constantly communicates details of its current position and planned direction of travel directly to the optics. Using this information, the optics continually calculate their own exact position in the working area; in doing this, they also takes account of clamping fixtures and only fire when the welding spot is fully accessible. The robot and optics are self-sufficient since everything happens without the addition of an intermediary “master” control unit. In this system, the optics themselves are the “master”.

compatible for use with any robot

on-the-fly-I-PFO

Probably the smartest scanner optics in the world: the I-PFO communicates with the industrial robot to achieve real processing on the fly. This requires the offline TruTops control software. (Photo: TRUMPF)

As a matter of principle, the I-PFO is compatible for use with any robot. Users do not have to use any particular brand in order to ensure successful communication between the two. In large-scale production, it’s possible to operate the I-PFO in an economical way since a single beam source is sufficient to provide up to six I-PFO optics with laser light simultaneously.

It is when it comes to changing over workpieces that the intelligence of the I-PFO is particularly evident. All the operator has to do is use the TruTops I-PFO software to quickly enter CAD data about the welding cell, robot, workpiece, and the desired welding spots. Then work can start straight away.

When components are changed, operators can simply use the robot’s hand-held programming unit in the cell to make any necessary ad­just­ment. The new programs can then be transferred without any problem to the virtual world of TruTops I-PFO again.

self-adjust to match current work­pieces

If a new type of workpiece is brought into the welding cell, the optics can process it immediately using the appropriate automation concept. This fulfils one of the key require­ments of a smart factory – that machines self-adjust to match current workpieces. There could also be other solutions that involve workpieces bringing along their own processing data – perhaps in the form of a chip or a laser marked code that selects the appropriate I-PFO program. It doesn’t get any smarter than that.

The first big customers have already been won over: one premium auto­motive manufacturer has been using the I-PFO since 2016.

Plastic welding with power control

PFO20-measures-and-regulates-temperature

Laser transmission welding of plastics: the PFO20 uses a pyrometer to measure the temperature directly in the melt. If the temperature is too high, the optics scale down the laser output in real time as appropriate. The welding result is perfect, scorching is avoided, and optimum bonding is assured. (Photo: TRUMPF)

In the laser transmission welding of plastics, the critical factor is the precision of the temperature generated in the workpiece by the laser beam. If the aim is to weld specific close contours such as acute angle corners, there can be scorching at the seam because heat accu­mulates and overlaps in the confined space. This causes the temperature to rise, resulting in burns that reduce the quality of the seam. In theory, the solution to the problem is simple: keep the temperature constant in the corner contours while the laser power output there is deliberately reduced. In practice, however, that is a tricky technical problem.

That’s why the engineers at TRUMPF have developed the new PFO20 welding optics with live temperature monitoring. A pyrometer is mounted on the rim of the optics and, guided by a number of mirrors, it looks directly into the melt along with the laser beam. If the melt temperature exceeds a critical level, which is adjustable, the optics scale down the power output of the laser beam in real time. In this way, operators can fully process every contour at the optimum welding temperature – and achieve durable and esthetic seams.

optimum welding temperature for every kind of plastic

Welding-of-plastics

In laser transmission welding of plastics, the temperature builds up in the corners of contours. That leads to scorching. This problem can be countered by reducing the laser output at these points and thus keeping the temperature constant. On the left, consistent power output leads to increased temperature and scorching; on the right, constant temperature leads to uniform process results. (Photo: TRUMPF)

As a result, the optics can process every kind of plastic at its optimum welding temperature. This makes things considerably easier for operators, who only need to think about the welding contour they desire – and then let the optics do the rest. As it goes about its work, the PFO20 also provides valuable data for quality assurance. Since the processing temperatures are known at every point in time for every workpiece, this furnishes important documentary support material. In the case of the PFO20, the principle also holds true that the optics react flexibly and self-adjust to match the current workpiece and materials. A number of automotive industry suppliers are already using the optics in production – such as for the welding of plastic components in vehicle interiors. The PFO20 is particularly suitable for axial applications such as welding sensor casings. In addition, TRUMPF also offers an integrated joint monitor as an optional extra.

Smart monitoring of fixed optics

Today, the BEO D 70 fixed optics, too, come with more thinking power. To match what is offered by CFO Controlled Focusing Optics, TRUMPF customers now also have the opportunity to upgrade the BEO D 70 with intelligent accessories.

  • Sensors monitor the temperature and flow rate of the optics’ cooling water and give a warning or raise an alarm if anything is abnormal.
  • Another sensor measures the scattered light reflecting onto the processing lens and gives a warning if levels are critical.
  • The protective glass monitor shows how contaminated the protective glass is and passes on the data to the TruControl control software.
  • Even for standard optics, TRUMPF now offers its Teleservice. After customers enable the Teleservice, service technicians will very quickly be able to connect directly to the laser and the intelligent optics via a data link. Lots of problems can be solved in this way by remote maintenance – and if that isn’t possible, the on-site service technician receives a detailed diagnosis of the fault.
  • An optional module monitors the crossjet air stream, which blows away smoke residue and weld spatter before they can contaminate the protective glass or the lens.
  • Another module monitors the pressure of the shielding gas supply in order to ensure that enough shielding gas always reaches the weld seam so as to achieve the best welding results.
  • Customers can also use a power measurement cartridge in their TRUMPF optics and make regular laser output measurements directly within the processing optics. That is particularly practical in tight mounting situations where there is no space to put measuring equipment underneath the optics.

All these options make standard optics more intelligent and deliver valuable data to aid production. In using them, customers extend the service life of their optics and lenses and at the same time also ensure a better process outcome.

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