Product category:
CNC laser cutting and profiling machines
News Release from: Bystronic Laser AG | Subject: Laser cutting technology
Edited by the Manufacturingtalk Editorial
Team on 26 May 2006
Integration of process produces best
laser cutting
If laser cutting process time is to be minimized and simultaneously, the quality of the cutting result is to be maximized, perfect integration of all process elements is required, reports Bystronic.
If laser cutting process time is to be minimized and simultaneously, the quality of the cutting result is to be maximized, perfect integration of all process elements is required, reports Bystronic A laser cutting process consists of much more than the procedures on the actual machine
This article was originally published on Manufacturingtalk on 30 Dec 2004 at 8.00am (UK)
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If the cutting time is to be minimized and simultaneously the quality of the cutting result is to be maximized, perfect integration of all process elements is required.
* Development - over the last two decades, laser cutting technology has developed at a meteoric rate.
Today's machine concepts exhibit an almost unbelievable level of maturity compared with systems in those days, the laser power has been multiplied and state-of-the-art cutting technologies have arrived on the scene.
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Choosing a laser profiling resonator
Laser profiling technology has bought about incredible innovation in the metal fabrication industry and Matt Orford compares the benefits of three types of laser profiling system resonators.
Is the difference between today's machines simply the price, or does the user automatically get the 'best' system if the laser power is maximized? Absolutely not, since even today the machines are significantly different and often confront a company that is ready to make such an investment with a real headache in finding the optimal machine for its own requirements.
Particularly since sub-contracting companies operate in a highly competitive market and the demands placed on them by customers in respect of production possibilities, delivery times and quality have successively increased.
To have laser cutting systems in the workshop, with which one is able to meet these demands in the best possible way has become a central competitive advantage.
From the customer's point of view, processing speeds continue to play a decisive role in the competitiveness of the user.
These include the pure part-processing times, but also - and this is only too readily ignored - the time from the construction right through to the final stacking of the cut parts.
A productive laser cutting system minimizes the processing time at all levels: Construction, data transfer, setting-up and loading the machine, cutting the parts and unloading the machine.
At the same time this system must guarantee that the quality of the parts meets the increased demands and that the quality is always reproducible.
As a manufacturer of such systems, one can satisfy these demands only if one succeeds in tying together all the individual facets - from the CAD/CAM software, the machine itself (including the laser source, the control package and the state-of-the-art cutting technologies) and through to the automation solutions - into a complete high performance package.
And what's more: A successful integration of the listed facets requires that they are developed and manufactured in-house, as is the case with Bystronic.
* Cutting technologies - a central element in minimizing part-processing times and simultaneously maximizing the cutting quality are state-of-the-art cutting technologies.
At Bystronic these are the result of an on-going dialogue with the individual customers.
Perfect examples of this are the scanning, the arc positioning and the modulation.
Scanning, an innovative method for the linear processing of square and oblong holes, is used on the Byspeed high-speed laser cutting machine.
The holes are no longer processed one after another, but first all edges that lie along the X-axis are cut and subsequently all edges that lie along the Y-axis.
Thus a significantly higher cutting speed is attained and a unique cutting performance achieved which makes possible the high-precision cutting of 5.5 holes/s.
Using arc positioning it is not only possible to move along the machine axis in a straight line but also in continuous arcs.
The automatic selection of the optimal positioning method is based on the cutting direction of the contour.
This procedure exhibits two decisive advantages: Firstly, the positioning speed can be kept constantly high and secondly the wear and tear on the machine is reduced since jerky changes of direction are not necessary.
An effective method to further increase the precision is the modulation, which permits the power of the laser to be adapted to the rate of movement.
If this is reduced, for fine contours or a change of direction, the laser power is also reduced.
This is an effective means of avoiding burnt corners or edges.
Piercing method - there have also been continuous advances in the development of piercing procedures.
One example of this is what is known as Controlled Pulsed Piercing (CPP), a truly innovative method developed by Bystronic that can be used for sheet metal thicknesses up to 25 millimeters.
In a two-level process, a guide hole is first pierced with the head at a large distance from the steel sheet in order to protect the nozzle and the lens from excessive dirt.
Subsequently the piercing of the hole is completed with a small head distance.
The clever part is that a sensor is built into the cutting head that based on the reflected light can detect precisely when the piercing is complete and report this.
The machine can then initiate the cutting process without delay.
This procedure not only saves time but also results in a minimal piercing hole, which with a 10mm thick steel sheet is a mere one millimeter.
Additionally, CPP increases the process security of the machine, since the steel sheet is heated to a much smaller degree and hence the danger of the jamming of the part is greatly reduced.
A further example in this respect is what is known as the 'lead-in' with zero piercing time.
This is no longer a piercing process but rather a direct cutting procedure without time loss, which can be used for materials up to eight millimeters thick.
Once in position it immediately starts with the cutting.
This red section can be fully parameterized.
At the start of the contour a changeover takes place to the cutting parameters with which the cutting process is to be executed, also without any delay.
Subsequently the machine moves in an arc to the next contour to be cut.
Compared with traditional piercing, when applied consistently this procedure makes it possible to achieve a reduction in the part cutting time of up to 35 percent.
* Hardware - in order to implement the cutting technologies and piercing procedures described above, it requires an intelligent machine concept on the hardware side and high quality laser sources.
As far as the laser sources are concerned, although when processing very thick metal sheets the laser power is an important factor it is certainly not the only criterion.
At least as important is the reliability of the resonator, particularly with regard to the consistency of the laser power or its pulse behavior.
For example, for the realization of the lead-in function the laser source must be capable of increasing and decreasing its power without any delay precisely at the desired point.
If this is not achieved then even the highest laser power is of no use, and the possible time advantages that can be achieved using 'lead-in' cannot be exploited.
Also, the cutting results can be improved if the diameter of the laser beam is maintained constant over the whole of the cutting area, something that is particularly important with large format machines.
At Bystronic, these requirements led to the development of the Bylaser 5200 ARC laser source that incorporates the innovative Adaptive Radius Control technology (ARC), with which the divergence of the laser beam is successfully counteracted .
And with a laser power of 5.2kW it has more than adequate power to cut metal sheets up to 25mm thick with an excellent quality, and additionally exhibits a precise pulse behavior.
But the cutting machine itself must also exhibit special qualities before the cutting technologies mentioned above can be used in practice.
The scanning, for example, places very high demands on the machine's drive motors.
Hence it is not surprising that also here Bystronic has adopted its own solution, and based on a directly driven spindle nut on a fixed spindle and linear distance measurement has developed what is known as the Direct Helical Motor (DHM).
And the perfect interaction of the machine concept and the applied cutting technologies alone results in clear time savings and first class cutting quality * Software and control - however, the cutting process does not begin on the machine itself but already with the construction of the part and the production planning.
The cutting technologies are integrated in Bystronic's own CAD/CAM program package Bysoft.
Bysoft incorporates a technology assistant that adopts the correct cutting technology for the respective geometry of the part.
Taking into account the type of material, its thickness and the process gas, the assistant recognizes the appropriate type of operation and the maximum possible cutting speeds that can be used.
Additional time savings are achieved at the software level thanks to the fact that the modular Bysoft software is designed such that the user can quickly learn how to apply and operate it.
Additionally, the software package is completely transparent, which means that once a data file has been opened it can be passed from module to module in an internal format.
Further mosaic stones in the process that must also not be underestimated, are the setting up and the control of the machine.
Hence it is advantageous if the control package also originates from the manufacturer of the machine.
Just a few months ago Bystronic launched ByVision, a control software that sets standards in respect of speed and user-friendliness that will be very difficult to compete with.
With a transmission rate of 100 megabaud even large cutting plans can be transferred in approximately five seconds, and at any particular time the ByVision touch screen displays only those functions that are currently necessary.
* Integration - from the given examples it becomes clear that the integration of the individual facets of the cutting process to form a fast and high quality system can only be ideally achieved if all the important components carry the same stamp.
This is precisely why Bystronic has for many years applied the philosophy of 'everything from a single source'.
On-going developments at one level are augmented by accompanying steps on other levels.
For instance, newly developed cutting technologies are incorporated in the software at once so that they are immediately available to the customer in practice, and an in-house control package is always more capable of taking full advantage of the systems capabilities than one that is bought-in.
Compromises, which in the final analysis are reached to the disadvantage of the user, are avoided.
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