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Trade fair: Glasstec Düsseldorf 2018

23 - 26 October 2018

With our third appearance at the Glasstec in Dusseldorf we were finally able to establish ourselves as a constant in the industry of glass production machine manufacturers. The Glasstec in Dusseldorf is the world's largest and most international fair for the glass industry and its suppliers. More than 1,200 national and international exhibitors present themselves at this fair. A lot of work was needed to make the fair a success. This year we shared the stand with the furnace builder IWG from Zwiesel. This cooperation was beneficial for both sides. With a total area of 203 m², the booth has set new standards for tableware manufacturers. Maximum attention could be generated by the running and fully functional Laser Filament Cutting Machine (LFC). For demonstration purposes, the LFC was equipped with glasses. So we could demonstrate the visitors that the system achieves the best achievable mouth rim quality, without grinding or washing. We have again confirmed that there will be no way around this technology in the future.

In addition to the LFC a linear glass testing machine was issued which also provides much interest among the visitors. Many new contacts were established on the four days of the fair and existing customer contacts were maintained.

“Laser Filament-Cutting” development

Laser filament system heralds a new era in glass production

To date, there are two different methods in glass production to separate the blowing cap from the glass.

On the one hand, in the post-processing, cold glasses are mechanically broken with a scoring wheel or a laser at the desired separation point.  A thermal impact causes a split at the connection.   A disadvantage of this method is the necessary surface grinding of the parting plane after the splitting process.  As an external force acts on the glass during this process, it is a mechanical process. Especially with very large, thin stem and thin-walled glasses this leads to more breakage and thus increased production loss.  Furthermore, after the grinding process, a washing process is required to eliminate the resulting grinding residue.  The additional abrasive and water use required for this process, as well as the subsequent water treatment are not only associated with increased effort, but also with additional production costs.  In addition, water residues often remain on the glass.

The second method is to reheat the glass in the hot zone, to introduce energy at the point of separation by means of a laser and to pull the cap off the goblet.  The disadvantage of this technology is that it is a thermal process.  In order to separate the blowing cap as evenly as possible and also to be able to produce a precisely defined parting plane, both the viscosity and the wall thickness distribution in the parting plane must be very homogeneous.  This, in turn, requires that the quality and the tolerances with regard to wall thickness distribution or geometric tolerances (concentricity, ovality, etc.) in general, caused by upstream machines (blow moulding machine, press), sometimes must be as exact as possible.  This cannot always be ensured in the manufacturing process, therefore consequently increased production loss due to poor quality and breakage occurs.  Another major disadvantage of this technology is the limitation in terms of the desired mouth rim quality.  This technology reaches its limits, especially with a very fine, filigree mouth rim expression.

In the last two years, we have developed a new separation process that avoids or eliminates the disadvantages of the original methods.  In the case of laser filament cutting (LFC for short), the glass to be separated is laser perforated with a multiplicity of holes at subsequent mouth rim  heights over the entire circumference of 360°, the so-called filaments (0.002 mm hole diameter separated by 0.007 mm spacing from one another).  Since only a kind of perforation is generated at the parting plane, after the laser process the blowing cap remains connected to the remaining glass through small webs between the filaments and can be separated by a short heat input.

The parting surface quality produced by LFC after separation of  the blowing cap is so uniform and fine, as well as free of  chippage, that further post-processing in the form of grinding, as well as the washing is no longer required.  Completely dry glasses in turn have a positive effect on subsequent steps in the production process (laser marking, labelling, packaging ...).  As early as October 2016, a hand-assembled LFC system was delivered to a customer, to take over the cap separation of the handmade stemware.

The aim was to incorporate this process into an automated system, which could be integrated directly a current production line.  Here we developed an 18-station LFC system including loading and unloading.  Two stations each form one segment, so that the system consists of a total of nine segments.  These are subdivided into loading, pre-centering, measurement, laser chamber, blow-off chamber, unloading and three spare segments, which could optionally be equipped with a camera test.