02.01.2025

Advantages of bench edge sanders

Building design

Bench edge grinding machines are indispensable for optimum edge processing of marble or granite. In an interview with STEIN, Dieter Löffler, Sales Manager at Löffler Engineering + Service GmbH, explains the special features and advantages of this machine and provides information on the possible applications. STEIN: Mr. Löffler, what is special about the Löffler table edge grinding machines? Dieter Löffler: Our edge sanding machines from the KSL series have […]

Dieter Löffler: “Our edge sanding machines in the KSL series have a stationary work table for placing the workpieces on which the machine carriage with the processing supports, which is guided on a rail system, moves past. This distinguishes the KSL 80 and KSL 100 series from an automatic belt machine. The KSL 80 is a single-disc machine for workpiece thicknesses from 10 to 80 mm. It has face supports for max. grinding wheel diameters of 150 mm. The KSL 100 MG, on the other hand, is equipped with triple planetary sanding heads DSS 250 N and can therefore process workpieces from 10 to 120 mm perfectly. With oscillating sanding heads, the sanding thickness can even be increased to 250 mm. Incidentally, in the course of the recent revision of the KSL series, the best Löffler assemblies were combined with those of our sister company Burkhardt-Hensel.

Löffler: Compared to automatic belt machines, automatic table machines are characterized by greater flexibility in terms of workpiece dimensions. Even large-format workpieces that need to be processed on several sides can be easily rotated on the worktable using lifting rollers and precisely aligned on a stop rail. Processing heads on long and narrow workpieces is also no problem with the automatic table machine. The exact alignment and clamping of the workpieces during processing ensures that optimum polishing results are always achieved on the face and chamfers.

This important advantage is particularly important today in the production of high-quality kitchen worktops. This applies to small and medium-sized companies as well as industrial worktop manufacturers.

STEIN: Are there also disadvantages to benchtop machines and how do you argue here?

Löffler: In direct comparison with conveyor belt machines, the supposedly larger space requirement of table-top machines is often cited as a disadvantage. However, taking into account the three-metre-long infeed and outfeed roller conveyors, a fully equipped automatic belt machine requires almost as much space as the KSL series tabletop edge sanding machines.

Another advantage of the tabletop machine is the much better accessibility for tool changes and maintenance work, as the machine slide can be worked on unhindered at the front and rear.

An automatic conveyor belt machine also permanently requires a machine operator who places the workpieces on the machine, monitors the infeed process and removes the workpieces immediately after they have passed through. Working with a tabletop machine differs in that the operator can leave the machine running unattended after placing the workpieces and starting the processing program.

A comparison of other edging machines

Have special technical features: CMG strip edging machines from L. Hietel

Hietel, a supplier and consultant to the stone industry and stonemasonry trade operating in Germany and Austria, supports both a manufacturer of table edging machines, “Euro Masiv”, and a manufacturer of band edging machines, “CMG”. The CMG machines have some special technical features: for example, the table frame is designed in such a way that the endless belt can be replaced without being destroyed – there is no need for welding or gluing on site.

According to Gerald Schwan, Hietel Sales Manager Machines & Technology, the very stable and extremely durable design uses largely tried and tested standard elements available in the industry, which results in low spare parts costs and a low operating hours rate. The upper chamfering units are always adjustable in height; this means that the center of the grinding axis always meets the workpiece corner (vertical material edge to horizontal material surface). According to Schwan, this leads to perfect chamfers thanks to the optimum slip ring contact point for all possible workpiece thicknesses. The basic equipment always includes an adjustable depth stop for the first supports from the side and for the chamfer at the top and bottom. Diamond tools can therefore be used to calibrate poorly sawn edges, for example – this also ensures uniform chamfers.

Optimized Steup model Nano

The Nano model from Steup-Engineering is ideal for companies with limited space, as it has a compact design but is still as powerful as the larger models. The machine is available with seven or eight surface sanding units and normally four bevel sanding units as well as a water grooving or multifunctional unit. The total machine length of four meters is not exceeded. In the largest version “STKA 8-6 NA” with eight surface and six bevel sanding units, the machine length increases to a total length of just 4.45 meters. The throughput height (material height) is limited to approx. 65 mm – which is perfectly adequate for the construction sector from today’s perspective.
An important component of the machine is the central water supply to the grinding wheels. This technology has been in use at Steup for 40 years and guarantees optimum sanding results when processing composite material. However, the machine can also be extended with an external water supply if mainly engineered stone is to be processed.
Another optimization – available since model year 2017 – is the pneumatically controlled pressure roller system “3-PLUS” with three pressure rollers per cylinder unit. The roller pairing is designed in such a way that even with a material width of less than 100 mm, two pressure rollers are still engaged.

Successful partnership: Goldschmidt and Marmo Meccanica

The Dortmund-based company Goldschmidt has been selling Marmo Meccanica’s edge polishing machines in Germany for more than 25 years. The product portfolio of the Italian machine manufacturer includes a variety of edge polishing machines for straight and round edges up to 100 mm material thickness.

In particular, the equipment and modular concept of the edge polishing machines enables individual adaptation to the respective customer requirements. For example, the LCV and LCH models can each be supplied in over 40 model variants. These edge polishing machines are equipped with 6, 7, 8 or 9 sanding supports – with or without oscillation – for face sanding. For the top and bottom bevel, 1, 2 or 3 supports can be configured. Additional supports can be used for mitre cutting, milling or sawing a drip edge (water nose), sawing notches, calibrating and much more.

The PLC control allows the automatic individual control of each pneumatic support and thus also enables partial processing of the workpiece as it passes through, which is ideal for the production of worktops in T or U shapes or for spiral steps, for example. It is also possible to produce grooves and bush-hammered areas on the individually selected workpiece section. A sensor on the input side detects workpieces that are not at right angles and support control is automatic. The edge polishing machines are operated via a self-explanatory touchscreen with memory function.

Auto-dynamic positioning for horizontal edgebanders

As one of the world’s three largest manufacturers of edge polishing machines, Marmo Meccanica is constantly developing its range of machines to meet user-specific requirements. For example, the horizontal LCH and LCG models can now be equipped with an electronic component, the auto-dynamic positioning of the upper chamfer support to the fixing point. The compensation of up to 5 mm fluctuation in the material thickness (min. length 50 cm) is automatically compensated. The workpiece coming from the saw can be inserted into the edge polishing machine with the polished side without turning. The auto-dynamic positioning of the upper bevel guarantees a constant thickness of the bevel on the polished side.

20.12.2024

Cultural heritage

Piero della Francesca in London: “The Nativity” is once again open to the public

Building design

Now open to the public again: The newly restored painting of the "Nativity" by Piero Della Francesca in the National Gallery London. Photo: © The National Gallery — Now open to the public again: the newly restored painting of the "Nativity" by Piero Della Francesca in the National Gallery London. Photo: © The National Gallery

After three years of restoration, “The Nativity” by Piero Della Francesca is now open to the public again at the National Gallery London

The National Gallery in London recently completed the three-year restoration of Piero della Francesca’s “The Nativity”. At the beginning of December, the National Gallery presented the freshly restored and newly hung and framed painting as its Christmas present to the British.

Christmas present to the British: The newly restored “The Nativity” by Piero della Francesca

The 124.4 x 122.6 centimeter painting, created between 1460 and 1475, is considered to be one of the last that Piero della Francesca painted before he went blind. It was once owned by the family (the Marini Franceschi family from Borgo San Sepolcro, a descendant of Piero della Francesca’s brother Marco). In 1861, it was bought by the Briton Alexander Barker. It was acquired by the National Gallery in 1874. However, the painting was in such poor condition that even the British Parliament inquired whether the work was original or complete. The painting was badly damaged – the faces of the shepherds were as if erased and the colors appeared dull – and the panel support was cracked. The first restoration work was carried out in 1884, followed by further work in the 1950s to repair the loss of colour and stabilize the fragile poplar panel.

The painting has now undergone another 36 months of extensive restoration with the support of the Rothschild Foundation and the London Old Master dealer Fabrizio Moretti. To coincide with the rehanging and reframing of the painting at the beginning of December 2022, the National Gallery published a video about the work, which was led by Jill Dunkerton. The lead conservator kept the interventions to a minimum, but retouched the depiction of the shepherds in part using Piero della Francesco’s precise underdrawings to enhance the overall impression.

You can find out more about the restoration work in the video here:

“Spending the last three years with this beloved painting has been a real privilege, but also a huge responsibility,” explained Jill Dunkerton, the lead conservator, on the occasion of the new presentation. “Every decision, every tiny brushstroke of retouching, affects our perception of the painting’s appearance and meaning, potentially for many generations to come. I hope that visitors can now experience the quiet magic of the painting without the distraction of past damage.”

New framing, new hanging in its own room

The restoration was eagerly discussed in the British press and on Twitter: Art Newspaper / ARTnews). The art critic Jonathan Jones, known for his polemical tone, complained in his column in the Guardian, among other things, that the painting had now been prettied up as if for sale at the London art fair “Frieze. But it’s best to see for yourself: since December 1, “The Nativity” by Piero Della Francesca has been hanging in its own room at the National Gallery, inviting visitors to contemplate it in silence.

We wish all our readers a Merry Christmas and a relaxing holiday season!

29.11.2024

Industry news, Profession

Sharing and discussing digitization experiences

Building design

The annual conference of the German Museums Association is the largest museum conference in Germany. From May 2 to 5, 2021, it will take place online on the topic of “Digital Collection Work: The Changing Museum” It has become a nice habit that the individual working groups also meet during the annual conference of the Museumsbund. Even in this year of the digitally networked […]

It has become a nice habit that the individual working groups also meet during the Museum Association’s annual conference. Even in this year of digitally networked working at home, this has not changed. Only the word “digital” appears more frequently than ever before and the opportunities offered by digitization are being used and discussed particularly intensively. It is therefore hardly surprising that the spring conference of the German Museums Association is being held under the extremely timely heading: “Digital Collection Work: The Museum in Transition” and will be held entirely digitally.

From 2 May 2021, digital experts and museum employees from all over Germany will present their thoughts on museum work in the age of digitalization. Legal issues will be addressed as well as questions of networked research and opportunities to earn money with digital museum offerings. A questioning look at the topic of “Digitality as the ultima ratio in culture?” will conclude the three-day exchange of ideas, which will be followed by the working group meetings on the fourth day of the conference.

The speakers describe the topic of the conservation/restoration working group as follows: “We would like to discuss the benefits and limitations of the digital in conservation and look at the tools currently relevant to our fields of activity.”

In a compact, digital two-hour meeting, four areas in which digital work is possible will be presented. One lecture will deal with the mediation of restoration work using the example of Ernst Ludwig Kirchner’s “Bathers in Space” in an exhibition at the Saarland Museum. The following lectures will present “Digital tools for conservators in the museum”, “Digital courier support” and a “Handreichung Leihverkehr”. The organizing team does not claim to cover all areas that can work with digital possibilities in these two hours. The aim is to deal with topics “that the pandemic has brought to the fore”, according to the invitation.

Nobody has to miss out on meetings with speakers, networking, discussions and break-time talks during this conference from home. The Museumsbund promises digital services for all these conference-specific options.

Registration for the annual conference of the German Museums Association is possible at https://www.museumsbund.de/aktuelles/jahrestagung/. To take part “only” in the working group conference, you also need to register with the Museumsbund. An invitation to the free TEAMs meeting of the working group will then be sent out.