Cavitation in ultrasonic technology

Cavitation is a physical phenomenon that plays a central role in ultrasonic cleaning. It occurs when high-frequency sound waves (typically between 20–80 kHz) are introduced into a liquid. This causes microscopic vapour bubbles to form, which grow rapidly and then collapse. These implosions generate high local temperatures and pressure peaks that remove dirt particles from surfaces – even in the finest structures and hard-to-reach areas.

Advantages of cavitation:
• Thorough cleaning without mechanical action
• Gentle on sensitive materials such as glass, metal and ceramics
• Effective on complex geometries (e.g. medical instruments, watch parts)
• Environmentally friendly, as less chemicals are often required

What is cavitation?
Cavitation refers to the formation and collapse of microscopic vapour bubbles in a liquid, triggered by rapid pressure changes. In ultrasonic technology, this effect is specifically used to clean surfaces effectively – even where brushes or chemicals fail.

The cavitation process
• Generation of ultrasonic waves
• An ultrasonic transducer converts electrical energy into high-frequency sound waves (typically 20–80 kHz).
• These waves propagate in the cleaning fluid and generate alternating high- and low-pressure phases.
• Formation of cavitation bubbles
• During the low-pressure phase, tiny vapour bubbles (microbubbles) form in the liquid.
• These bubbles are unstable and grow over several cycles.
• Collapse of the bubbles
• During the high-pressure phase, the bubbles implode abruptly.

Cleaning effect
• The implosion generates microjets and shock waves.
• These act directly on the surface of the object to be cleaned.
• Dirt, oil, oxidation and particles are mechanically removed – even in crevices, boreholes or rough structures.

Temperature of the liquid:
• Higher temperatures promote bubble formation and improve the cleaning effect.
• Type of cleaning liquid

Soprod is a Swiss manufacturer of watch movements and components and is now part of the Festina Group.

Soprod SA Les Reussilles was founded on 16 September 1966 in Tramelan in the Swiss Jura with the aim of manufacturing mechanical watch components on an industrial scale.

Later, Soprod became a general movement manufacturer and assembled movements for other companies, including ETA. The company was acquired by Léman Capital and merged with Swiss quartz specialist SFT Group in 2005 to form a new company. The company hoped to create an alternative to the ETA 2892-A2.

This group was acquired in 2007 by Peace Mark from Hong Kong, which, however, went bankrupt the following year. STM was bought back in 2008 by Festina's management, without the quartz production for the mass market that the company had established in China.

Today, Soprod is the parent company within the Festina Group, which manufactures components for Swiss watches.

Soprod's most important mechanical movement is the Soprod A-10, which is based on the Seiko 4L family. On this basis, Soprod also manufactures a range of complications, including large date, second time zone, power reserve indicator, 24-hour display, chronograph, moon phase and more. Soprod also manufactures escapements and balance springs for other manufacturers.

Boley is an official LISTA sales partner and supports you in planning your workshop.

PLANNING & SERVICE
Professional support for your workshop equipment with BOLEY and LISTA.

As a LISTA sales partner, we provide you with expert support in the selection and configuration of high-quality drawer cabinets and workshop equipment. Are you planning a new project or would you like to optimise existing work areas? Then benefit from our experience and comprehensive product knowledge.

Individual advice for customised solutions
Whether workshop, warehouse, production or office - we will advise you personally and according to your needs. Together we will analyse your requirements and help you to put together the right LISTA solution. Even if you have special requirements, we will work with you to find the right product selection from the diverse LISTA system.

Service-orientated - from the idea to the order
We provide you with reliable support from the initial consultation to the order. Thanks to our close partnership with LISTA, we can respond flexibly to your wishes and offer you a wide range of options - for a well thought-out and functional furnishing solution.

Nacre Pearls are high-quality artificial pearls that are designed to look and feel very similar to real pearls. They consist of a crystal core that is coated with several layers of nacre (mother-of-pearl) - hence the name.

Properties of Nacre Pearls:

• Silky-smooth surface with a mother-of-pearl-like lustre
• High shape and colour uniformity - ideal for jewellery design
• Robust and durable as they are not as sensitive as real pearls

They are particularly popular for DIY jewellery, pearl necklaces, bracelets or earrings. Nacre is the material that real pearls are made of - it is formed from shells and is known for its iridescent lustre.

Real pearls vs. nacre pearls - recognising the differences
All important differences are listed in the table. If two real pearls are rubbed lightly against each other, you will feel a slightly rough resistance - with artificial pearls, the surface is smooth and glides without friction.

How to work with Nacre Pearls
The pearls are threaded with normal pearls - with pearl thread, wire or elastic band. The ends are stylishly secured with crimp beads and calottes.
These beads are also ideal for earrings, bracelets, necklaces, hair jewellery or buttons.

Since 1866, GRIFFIN 1866 has stood for the highest quality in the manufacture of stringing materials. Founded by trimmer Karl Schinle in Schramberg, the company recognised the jewellery industry's growing demand for professional thread for necklaces and colliers at an early stage.

Thanks to close contacts with the jewellery town of Pforzheim, GRIFFIN quickly developed into the leading manufacturer of pearl silk - then as now a purely natural product with a special status.

GRIFFIN established itself worldwide under this brand and today offers modern high-tech fibres and jewellery wires in addition to classic silk.

Innovation and technical expertise are still central pillars of the company today. In-house machine developments and state-of-the-art production methods guarantee consistently high product quality.

Gebrüder Boley - Your specialist for high-quality beading ropes and accessories

For decades, Gebrüder Boley has been a close partner and leading supplier of the highest quality pearl silk and accessories. Our experience and our range guarantee quality, durability and perfection, so that every piece of jewellery is given its unique shine.

• Exquisite pearl silk for precise craftsmanship
• Comprehensive accessories for professional jewellery design
• Reliable quality thanks to many years of expertise

Discover our range and be inspired by our selection!

Since 1793, ETA SA has been setting standards in the development and construction of the finest movements. Deep-rooted expertise has laid the foundation for one of the world's largest manufacturers of wristwatches and movements. Research, innovation and first-class service form the foundation of its philosophy: every single movement - whether quartz or mechanical - receives the utmost attention. The best materials, outstanding quality, precision, reliability and performance are the core values of their products.

As a leading player in the watch industry, ETA draws on a unique heritage. With unrivalled technical, industrial and human expertise, they use their decades of knowledge to actively shape the future.

Boley - your reliable partner for ETA spare parts

For decades, Boley has been a trusted partner of ETA when it comes to high-quality spare parts for quartz and mechanical movements. Our extensive stock offers a huge selection of ETA components, so you will always find the right parts for your watch.

• Browse our database - Find precise spare parts for ETA movements.
• Large selection - From quartz movements to mechanical components - all in one place.
• Customised advice - If the part you are looking for is not in our database, please do not hesitate to contact us directly.

Our experience and our product range ensure that your movements can be serviced with reliable original parts. We are here for you - contact us!

The weekend workshop on 17.05. and 18.05.2025 on the subject of PUK fine welding was a complete success!

The latest fine welding technology was the topic of this seminar, which took place on the premises of Gebrüder Boley. In cooperation with Lampert Werktechnik, Gebrüder Boley also succeeded in organising a workshop on PUK fine welding in 2025. The participants took the opportunity to work live on the latest generation of PUK 6.1 welding machines.

The 2-day seminar took place last weekend on Saturday, 17 May and Sunday, 18 May 2025 under the direction of Susanne Englert, trained master silversmith and lecturer at the state drawing academy in Hanau.

The workshop focussed on the following topics:

• Repairs to delicate workpieces, including the welding of ear studs and settings.
• Welding in MICRO and PIN mode for welding on ear stud pins
• Fixation welding for attaching objects
• Treatment of individual special applications

The participants had brought their own jewellery and watches with them. Mrs Englert was able to use these as examples to work out solutions to problems for all participants and thus provide important tips for everyday workshop work. The focus was also on the exchange of experiences between the participants.

The participants spoke of a very successful workshop, which is offered annually in this form by the company Gebrüder Boley. We would like to take this opportunity to express our sincere thanks to all participants and especially to Mrs Susanne Englert and Lampert Werktechnik for their commitment.

Hermle movements for large clocks are indeed fascinating!

The publication of the installation dimensions in our online shop makes it much easier for watchmakers and repair experts to find suitable alternatives for large clock repairs.

Hermle movements enjoy an excellent reputation, especially for their precision and durability.

• Quality and workmanship: Hermle movements are known for their high-quality workmanship and the use of durable materials. They offer impressive accuracy, making them a popular choice for large clocks.

• Versatility: Hermle offers a wide range of movements suitable for various applications. This makes them a flexible option for watchmakers and repair experts.

• Price-performance ratio: Compared to other brands, Hermle movements offer a good balance between quality and cost



And this is how it works:

To find the installation dimensions of Hermle movements in our online shop, simply go to the desired category. There you will find a practical PDF document with the installation dimensions for each calibre, which will help you to check the interchangeability for your large watch repairs

Waldmann - 20-year guarantee

Imagine: at least 20 years of worry-free working thanks to our reliable lighting! We are so confident in the quality of our products that we offer you an exceptional 20-year guarantee. Our lights are made in Germany and designed to withstand the highest demands - today, tomorrow and for many years to come. The outstanding quality is the result of the commitment and expertise of our employees, who work with state-of-the-art production processes and sustainable technologies. Place your trust in Waldmann lighting for a long lighting life.

Why can we offer this guarantee with such conviction?

Quality “Made in Germany”:
Our luminaires are manufactured in Germany and undergo rigorous testing in our in-house light and test laboratories. The result? Products you can rely on worldwide.

Over 95 years of experience:
For almost a century, we have been developing and manufacturing luminaires that meet the highest quality standards. Our many years of expertise allow us to offer such a comprehensive guarantee.

Our own development department:
From the initial idea to the finished luminaire – we develop our products ourselves and work closely with our suppliers. This is how we ensure that only the best materials are used.

Worldwide service:
Our team is always at your disposal. Should a problem arise, you can rely on our fast and reliable service.

Repairability and spare parts:
Sustainability is an important topic for us. Our products are designed to be repairable. We provide spare parts throughout the entire warranty period, of course, to protect your investment.

professional precision welding with the PUK

**Welcome to the Boley workshop on 17 & 18 May 2025 in Stuttgart **

You can now register for our professional workshop on PUK fine welding. We will provide you with comprehensive support and offer you a practical exchange of experience with our qualified speaker.

Under the leadership of Ms Susanne Englert, master silversmith and current teacher at the stately Drawing Academy in Hanau, we are offering you this workshop with extensive training and exchange of experience on 17 & 18 May 2025 at our premises in Stuttgart. You will be trained on the latest ‘PUK 6.1’ equipment from Lampert Werktechnik and only need to bring your own pieces of jewellery and watches as practice pieces.

We have the following focal points in store for you on this workshop weekend:

• Applying metals
• Welding silver
• Carrying out ring changes
• Welding ear studs
• Welding of settings
• Repair of metal bands
• Reconditioning of watch cases
• Treatment of your individual special applications

Please note that the number of participants is limited to ten. We therefore look forward to receiving your prompt confirmation using the PDF registration form attached below or simply send us your written confirmation to support@boley.de.

The problem of testing gold jewellery

Authenticating gold jewellery is a major challenge. Due to the very diverse geometries (rings, necklaces and ear studs, etc.) and the composition (different mixed gold alloys in different carats), it is impossible to determine gold jewellery exactly using only one test method. The most common types of counterfeit jewellery are

• Counterfeit jewellery with base metals: This refers to the plating of a base metal with gold. This often occurs with rings or chains made of tungsten or tungsten carbide, whereby these materials almost perfectly imitate the density and thus the “heavy feeling” and feel of real gold jewellery.
• Under-alloying / hallmark fraud: If the gold content of an alloy is lower than specified by the hallmark.
• This can also be done in an even more sophisticated way, in that the surface of the piece of jewellery has the correct alloy and the underlying material is worthless foreign material or an inferior alloy.

Due to the large number of different types of gold alloys and jewellery geometries, the testing of jewellery is more demanding than that of gold bars, for example. The following testing methods should therefore be available when purchasing jewellery.

1. Electrochemical testing using the "CaratScreenPen ".
The CaratScreenPen uses an electrochemical process to determine the purity and fine gold content on the surface of gold and platinum jewellery. The measuring tip forms a so-called “galvanic cell” on contact with the object lying on the measuring surface. This results in a certain electrochemical behaviour, which is registered by the measuring tip and processed by the device.

2. density scale "DensityScreenScale "
You can use the density scales to quickly and precisely determine the density of all types of materials. It is equally suitable for analysing bars and gold jewellery to determine their purity and alloy composition and to determine bars or jewellery that have been “stretched” or under-alloyed with silver or copper. The density is determined using the tried and tested method of Archimedes: To do this, the object is weighed with a sieve under water and once “normally”. The density can be determined directly from the two different values. This gives you an insight into the quality and carat of the gold or even an initial indication of the possible presence of forgeries. Determining the authenticity and gold content of geometrically irregular objects such as jewellery is therefore no problem.

3. magnetic scale "MagneticScreenScale "
A sustainable method for measuring bars and coins is to determine the so-called magnetic susceptibility properties. This makes it possible to determine, even through blister packs and packaging up to a certain thickness, whether the material applied has the correct magnetic behaviour - para- or diamagnetic, i.e. attractive or repulsive. A so-called “tungsten detector” can be used to determine the presence of a potential foreign body: a gold bar as a so-called diamagnet displaces a magnetic field, creating pressure on the measuring head of the scale and displaying a positive value. If a supposedly genuine fine gold bar is placed on the scale and a negative value appears, it is in most cases a fake.

4. surface testing with test acids or X-ray fluorescence analysis

• The gold coating sample with test acids: In principle, the first, relatively simple and cost-effective step is to determine the gold content using gold test acids.
• X-ray fluorescence analysis (XRF): This determines the exact elemental composition of the jewellery on the surface. This method is very expensive (approx. 15,000 - 45,000 EUR) and is purely superficial: the maximum penetration depth is only 0.010 mm.

The complete and detailed article on the methods of gold testing can be found here:

Trends & highlights from Inhorgenta Munich 2025

INHORGENTA 2025, Europe's leading platform for jewellery, watches, gemstones and technology, once again set new standards from 21 to 24 February 2025: with over 25,000 trade visitors from around 100 countries and 1,338 brands from 38 countries, INHORGENTA 2025 got off to an impressive start to the year. With an increase in visitors of just under 1 per cent and exhibitors of 3.4 per cent compared to 2024 and a foreign share of around 40 per cent, the growth figures are more modest than in previous years, but they prove the increasing internationalisation of this trade fair.

GEBRÜDER BOLEY celebrated 165 years of commitment and passion for its customers at the trade fair. To mark the occasion, visitors to the stand were presented with a surprise package containing a wide range of tools and care products. Team Boley and the two owners, supported by Pascal Lutz - who has been actively involved with Boley for 2 years - and Marco Lutz, who will join them later this year, were delighted to welcome numerous new and regular customers.

GEBRÜDER BOLEY can look back on a successful trade fair. This year's sales focussed on the following trade fair trends and highlights:

1. everything around the gold purchase: Precision scales for buying gold, gold analysis scales, testing devices for determining the gold content of jewellery, bars and coins
2. testing equipment for analysing the authenticity of colourless gemstones to differentiate between simili, moissanites, laboratory-grown diamonds (CVD / HPHT) and natural diamonds
3. CNC-controlled engraving machinen for the personalisation of watches, jewellery and daily necessities
4. newly revised casing tables with integrated ‘Leica’ microscope units and extensive accessories

‘We were once again positively surprised by the number of visitors and the international character of the trade fair and will certainly not miss the 52nd INHORGENTA next year,’ says Michael Lutz, Managing Partner of GEBRÜDER BOLEY.

the generation change is imminent!

This year Gebrueder Boley proudly celebrates 165 years of commitment and passion for its customers. Over 10,000 retail customers from more than 60 countries rely on the expertise of the company expertise of the company, which as a full-range supplier of watch and jewellery technology more than 120,000 articles.

To mark its anniversary, Gebrüder Boley is not only presenting the latest innovations at the INHORGENTA 2025 trade fair, but also the next generation of the company's management. Pascal and Marco Lutz are the successors in what is now the fifth generation. Visitors can look forward to innovative products and trade fair novelties such as the

the new generation of Flexbo 4.0 drum tables
• The new generation of Flexbo 4.0 setter’s benches
• the ‘Leica Ivesta’ setter’s microscope sets
• the computer-controlled engraving machine ‘GravoTech M20X’ with user-friendly touchscreen
• the next generation of GRS setting and graving systems powered by compressed air
• New burs innovations from Busch, made of carbide steel
• Furthermore, combined testing devices for the differentiation of natural and synthetic diamonds, the so-called ‘lab-growns’, will be the focus of attention.

Visit us at the you will find us in hall C2, booth No. 302. We look forward to your visit!

Your Boley exhibition team

Horotec supports Gebrüder Boley at the Inhorgenta 2025 traide fair
10% Discount on all Horotec Tools

Did you know that Horotec from La Chaux-de-Fonds in Switzerland, the world-renowned supplier of watchmaking and precision engineering tools, and Gebrüder Boley have been working together successfully for several decades?

And this co-operation is growing from year to year, so that Boley is currently one of Horotec's leading sales partners worldwide. Both companies co-operate regularly at trade fairs and other events. At the INHORGENTA stand of Boley in Hall C2, Horotec will be presenting the following interesting innovations, among others:

• Universal tool for milling, drilling and deburring (Boley Art.-No. 514700)
• Dial kit for setting the dial feet (Boley Art.-No. 514710)
• Professional grinding tool for screwdriver blades (Boley Art.-No. 511266)

You will also benefit from a 10% discount on all HOROTEC tools in February 2025. You can experience many of these tools live at the Boley stand at INHORGENTA.

In addition, Boley stocks over 300 Horotec tools online. If you cannot find a Horotec reference in our online shop, please enquire via chat or email by support@boley.de for the price and availability. We can usually get you the desired Horotec item at short notice.

Your Boley Team

Voucher code: HOROTEC25 (valid until 28/02/2025)

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