Gentle finishing of extremely hard surfaces

Overlapping rotational work piece movement is the basis for even, all-around surface finishes

Gentle finishing of extremely hard surfaces

The spindles allow the processing of batches of up to 18 work pieces. For this photo different work

At this year“s IMTS Walther Trowal is introducing the new drag finisher M-TMD 6M for treating high-value components that require a first-class surface quality. The new drag machines will place a mirror polish on the hardest materials – even on ceramic components. With these machines the costs for polishing can be reduced to a fraction of the costs for manual surface grinding and polishing. But even more important: They ensure absolutely repeatable, high-quality finishing results within an extremely narrow tolerance band.

Walther Trowal developed these new machines specifically for treating high-value components requiring extremely careful handling for the complete finishing process. For example, they are utilized for finishing the surface of turbine blades, impellers for turbo chargers, precision components for pumps and compressors as well as for orthopedic implants.

The new drag machines of the M-series have a carousel with multiple rotating workstations. In turn each workstation is equipped with spindle heads containing several spindle drives onto which the work pieces are attached with special fixtures. In addition, these machines also contain a stationary work bowl filled with grinding or polishing media. As the work pieces are „dragged“ through the stationary media mass, the simultaneous rotational work piece movement by carousel, workstations and spindles creates different overlapping patterns, which ensure an even and intensive coverage of the complete work piece surface.

Christoph Cruse, director of sales at Walther Trowal, foresees a big demand for these machines at some of his customers who produce delicate, high-value components. He explains: „With our new machines we want to assist the manufacturers of work pieces that must receive the best possible surface finish, and where even the slightest surface flaw or scratch might cause them to be scrapped. Furthermore, we target parts where deviations from the dimensional specifications of a few thousands mm can be a detrimental. The M-TMD drag finishers with their perfect surface coverage open brand-new possibilities for finishing such work pieces.“

Die M-TMD 4 drag finisher is equipped with four work stations and can process 12 parts in one single batch; the M-TMD 6 – with six work stations allows batch sizes of up to 18 pieces.

At this year“s IMTS Walther Trowal also displays a range of mass finishing equipment including rotary vibrators, the MV multi vib vibrators and a high-energy centrifugal disk finishing machine.

One drag finishing success story:
Polishing of the extremely wear resistant ceramic coating on orthopedic implants

One example for the successful use of the new drag finishers is a process, specifically developed by Walther Trowal, for polishing of knee femorals made from a chromium-nickel alloy, which are covered with a ceramic coating applied with a special vapor deposit method. To date these parts had to be finished manually in time consuming multiple steps with the risk of high quality fluctuations.

After a pre-grinding step the ceramic coating is polished in the new M-TMD drag finisher with a polishing medium specifically developed for this application. The result: Although the ceramic coating is extremely hard, the drag finisher produces a very smooth, shiny and highly wear resistant finish from the initially rough surface condition. The new coating extends the fatigue life of the implants from to date about 20 up to 30 years!

In developing this process Walther Trowal took an entirely new approach. Instead of using relatively soft polishing materials the company is adding an extremely hard substance to the polishing medium, namely diamond powder.

Christoph Cruse explains the advantages of the new process as follows: „Soft materials can be polished relatively easily. But the manual polishing of extremely hard coatings has been extremely difficult, especially because an even surface finish is essential for the functionality of the component. In the case of vapor deposit coating, with a layer thickness of just a few microns, it is essential not to remove too much of the coating material from the part surface. With the M-TMD drag finishing technology and the new polishing media we have resolved this difficulty: The finish is absolutely even on the entire surface area of the implants.“

Walther Trowal at the IMTS 2018
September 10 – 15, 2018, Chicago, IL, USA
North Building, Level 3, Booth 236609

The technical details

In standard drag finishers the work pieces are directly mounted to the workstations and „dragged“ through the stationary media bed producing an extremely high processing intensity. This method is more than adequate for most work pieces and produces excellent finishing results.

The new M-TMD systems allow one additional rotational movement, namely that of the spindles mounted to the workstations. The multi-spindle heads on the workstations can be also be angled allowing the adaptation of the media coverage on the work piece surface to different work piece geometries.

All process steps, from cut-down, over surface smoothing to the final polishing, take place in the same machine, without having to remove the work pieces from the spindles.

The new drag finishers are suitable for dry as well as wet processing. In wet processes for cut-down, surface smoothing and, occasionally, for polishing, special finishing compounds are used. For the targeted edge radiusing within a tolerance range of a few thousands mm, like for example for tungsten carbide drill bits or milling tools, dry grinding media are utilized. Dry processing is also used for high gloss polishing with special pastes and polishing media.

Facts about Walther Trowal

For 85 years Walther Trowal has been a pioneer and market leader in various surface treatment technologies. The company offers modular and custom engineered solutions for a wide range of surface treatment problems.

Initially only making vibratory finishing equipment, over the years Walther Trowal has continuously broadened its product range and today offers a wide portfolio of equipment and services for improving all kinds of surfaces, e.g. mass finishing, part cleaning, shot blasting and drying of a wide spectrum of work pieces, last but not least, the coating of mass produced small parts.

Walther Trowal offers not only various types of equipment but complete surface treatment systems: By linking the various equipment modules and automating the complete process, we are able to precisely adapt our process technologies to the technical requirements of our customers. This also includes various types of peripheral equipment and process water cleaning and recycling systems. Of course, we also offer comprehensive pre- and after-sale service like sample processing in one of our demonstration labs and global repair and maintenance service.

Walther Trowal serves many customers in many industries around the world. For example, in the automotive and aerospace industry, medical engineering and wind power generation.

Walther Trowal in America

The recently opened „Tech & Training Centre“ of the Walther Trowal LLC in Grand Rapids, Michigan has, among other equipment, a test lab for the „Trowal Coating“ technology allowing interested customers informing themselves about the most suitable coating method for their work pieces.

Trowal has also extended its presence in Latin America by recently opening a sales office in Mexico, which is, of course, using the knowhow and resources of the Grand Rapids facility.

Walther Trowal GmbH & Co.KG
Georg Harnau
Rheinische Str. 35-37
42781 Haan, Germany
+49 2129.571-0
+49 2129.571-225

VIP Kommunikation
Regina Reinhardt
Dennewartstraße 25-27
52068 Aachen, Germany

Optic chip with a long service life

Success for Retina Implant – retinal implant still functioning after more than 50 months

Optic chip with a long service life

The subretinal implant Alpha AMS by Retina Implant AG (Source: Retina Implant AG)

(Reutlingen) – The subretinal implant from Retina Implant AG has successfully demonstrated its long service life under real-life conditions. Implanted back in 2014, the chip is still functional and has enabled a previously completely blind RP patient, now in her 70s, to perceive light. The fact that the implant has thus exceeded a service life of over 50 months is a great technological success for the Reutlingen-based medtech company.

Retinitis pigmentosa (RP) is a degenerative retinal disease that leads to the destruction of the retina and often total blindness in the final stage. It is regarded as a „rare disease“, yet affects 20,000 to 30,000 people in Germany alone and around three million individuals worldwide. Retina Implant AG from Reutlingen has developed a subretinal implant that is able to restore partial sight to people who perceive very little or no light due to various forms of degenerative retinal diseases such as RP.

In Tübingen, an RP patient who had already lost all her sight received the implant in 2014. The chip implanted in the patient, now in her 70s, has been in operation for more than four years – and still functions as it did in the beginning. For instance, the patient can identify light sources and therefore find her way around more easily. „One of the greatest challenges when developing the implant was ensuring the camera chip in the eye would remain functional over many years,“ explains Dr. Alfred Stett, CTO of Retina Implant AG. „Unlike pacemakers and neurostimulators, which have their electronics and battery packaged in a fixed, hermetically sealed casing, our electronic chip is in direct contact with the retina – a light-permeable barrier layer that is a few micrometres thick is the only form of protection.“

The subretinal implant features 1,600 photodiodes and stimulation contacts that partially replace photoreceptors destroyed by RP. The chip is only around 12 square millimetres in size and is placed directly below the fovea centralis, which means it can move with the eye to locate objects. The latest generation of the implant, known as the RETINA IMPLANT Alpha AMS, was awarded CE certification back in 2016. In Germany, the cost of the implant is reimbursed by the statutory health insurance providers.

„Our forecasts regarding shelf life were previously based on ageing tests conducted in the laboratory and on model-based estimates of service life that are commonplace in the aviation industry, for example. These tests and estimates predicted a service life of 4.7 years. Our patient’s experience shows that we are on the right path. This success is the result of 15 years of intensive research and development to give blind people fresh hope,“ says Dr. Stett.

25 August 2018 Patient information day for congenital retinal diseases at Knappschaftsklinikum Saar GmbH, An der Klinik 10, 66280, Sulzbach, Germany, Augenklinik Sulzbach (Sulzbach Eye Hospital).

About Retina Implant AG
Retina Implant AG researches and develops innovative treatments and high-tech products for people suffering from retinitis pigmentosa (RP). The subretinal RETINA IMPLANT Alpha AMS can help blind patients regain a certain degree of useful sight. The CE-approved microchip is implanted beneath the retina (subretinally) at specialist RI implantation centres.
Transcorneal electrical stimulation (TES treatment) with the RI OkuStim® system offers RP patients with sufficient residual vision the opportunity to slow down the progression of the disease.
The company, based in Reutlingen, employs around 45 people and is managed by Reinhard Rubow (CEO and speaker of the Management Board), Jürgen Klein (Member of the Board, Sales & Marketing) and Dr. Alfred Stett (CTO, Member of the Board).

Retina Implant AG
Volker Hiller
Gerhard-Kindler-Str. 13
72770 Reutlingen
+ 49 71 21 3 64 03 – 282

Zeeb Kommunikation GmbH
Anja Pätzold
Hohenheimer Straße 58a
70184 Stuttgart
0711-60 70 719

mediCAD Hectec welcomes users of Localite OrthoPlanner

mediCAD Hectec welcomes users of Localite OrthoPlanner

With a handshake Jörn Seel, mediCAD Hectec, and Martin Bublat, Localite, seal the takeover.

(Landshut/Sankt Augustin) Localite GmbH is ceasing development of OrthoPlanner. In response, mediCAD Hectec GmbH is making it easy for existing users of OrthoPlanner to switch to the current version of its mediCAD digital pre-op planning solution. The mediCAD Classic 4.0 digital planning system is based on a database of more than 500,000 implants from more than 130 manufacturers around the world.

Moving forward, orthopedic practices and hospitals that plan operations with Localite’s Orthoplanner solution will be supported by mediCAD Hectec. Orthoplanner users can easily switch to the mediCAD digital planning solution, which is already in widespread use internationally. The manufacturer of OrthoPlanner will no longer develop the product. According to Jörn Seel, Managing Director of mediCAD Hectec GmbH, „A straightforward upgrade to mediCAD gives practices and hospitals access to a comprehensive and modern solution that is ready for future challenges. It includes a database of implants as well as Hip, Knee, and Osteotomy modules. We update medCAD online every month.“

mediCAD has a number of special features, including mirroring of the intact side to the deformed side, bilateral deformity correction, including Dror Paley, automated corrective osteotomies near the tibia, intertrochanteric osteotomies, direct transfer of planning data to EndoDok, and automatic detection of the calibration sphere. The software even integrates mobile devices, giving doctors immediate access to planning data from virtually anywhere. Any changes made on a mobile device are then sent directly to the PACS system.

The upgrade costs €499.00 (practice license) or €1499.00 (hospital user license) per workstation, including online installation and online introductory training. On-site training is available at any time for €1299.00, plus travel expenses. Conclusion of a maintenance contract (€299.00 for practice / €1500.00 for hospital) is required.

Hectec GmbH
Hectec GmbH has been continuously developing its „mediCAD Classic“ planning solution since 1994. This digital solution integrates all essential planning methods and documents processes for legal security. It covers every area of orthopedic surgery, from hips to shoulders and from feet to knees and the spinal column. „mediCAD Classic“ is a certified solution and has global approval as a medical product. „mediCAD Classic“ is distributed exclusively through authorized partners. As of early 2016, Hectec GmbH collaborates with 120 sales partners around the world. Approximately 4,000 hospitals currently use the solution. It is based on a database of implants that contains items from more than 110 manufacturers. Aside from implants, surgeons can also select from an extensive range of osteosyntheses for planning purposes in mediCAD. In addition to its classic and well-known 2-D solution, Hectec also offers 3-D planning software and a solution for mobile devices.

Hectec GmbH
Jörn Seel
Opalstr. 54
84032 Altdorf
+49 (0) 871 – 330 203-0
+49 (0) 871 – 330 203-99

TennCom AG
Dr. Kurt-Christian Tennstädt
Hohentwielstr. 4a
78315 Radolfzell
+49 (0)7732 – 95 39 30
+49 (0)7732 – 95 39 39