Vol. 23
January Issue
Year 2022


in Vol. 23 - 1 Issue - Year 2022
How Developments In The Field Of Consumables Are Creating New Application Opportunities For The Mass Finishing Technology

Christian Höhn, Head of Technology Management at Rösler Oberflächentechnik GmbH in Germany

The Rösler KeramoFinish® process is highly effective for creating very smooth functional or decorative surface finishes. It became possible by the development of non-abrasive, high-density porcelain media and suitable grinding and polishing pastes

The development of a highly effective pre-polishing media was one of the reasons for Rösler becoming a major supplier in the field of orthopedic implant finishing

The “multi-shape” ceramic media significantly reduces the risk of media lodging, particularly in case of complex work pieces with difficult-to-reach internal surface areas, including tight edges, notches and slits

Non-foaming plastic media greatly simplifies the handling of finishing processes. In addition, it helps reduce cycle times and eliminates the need for expensive rework.

The recently developed anti-dust compound drastically reduces the amount of residual dust when the finished workpieces are dried with organic drying media like shredded corn cob or crushed nut shells

More than 70 years have passed since the first mass finishing vibrator was invented, so it would be understandable if mass finishing was looked upon as a so-called “sunset industry” whose importance in the surface refinement market is declining. Quite the opposite is true! Thanks to a continuously expanding range of inventive finishing applications, this “old” technology is more relevant than ever in today’s manufacturing environment. It allows for effective and cost-efficient surface finishing, be it simple deburring or high gloss polishing, of extremely complex and delicate work pieces. This also includes the treatment of difficult-to-reach surface areas like internal passages, undercuts, drilled holes, etc. Mass finishing processes are always defined by the interplay between the machinery on the one hand and the consumables – media and compound – on the other; therefore, it is not surprising that to a large extent, the creation of new applications is driven by new, innovative products in the field of media and compounds. MFN had the opportunity to discuss some of these exciting developments with Christian Höhn, Head of Technology Management at Rösler Oberflächentechnik GmbH in Germany.

(?) MFN: Christian, could you tell us a bit more about the function and the responsibilities of the “Technology Management” at Rösler?

(!) C. H.: Of course. In our mission statement, we have clearly stated our goal of becoming the world’s leading company in the field of surface treatment. Naturally, we recognize that for achieving such an ambitious goal, our company must be more innovative than our competitors. Therefore, all functions of our product management teams for mass finishing and shot blasting as well as our customer experience centers for mass finishing and shot blasting were merged into the Technology Management department.
This integrated approach allows a highly coordinated and systematic observation of the market for surface treatment and enables us to quickly adapt our existing products to the latest market requirements and, if needed, to develop brand-new products. Of course, all this takes place in close collaboration with our colleagues from the R&D team.

(?) MFN: Do we understand you correctly that the product management for mass finishing and shot blasting and the respective demonstration centers are all part of the Technology Management?

(!) C. H.: That’s right. We consider both technologies as highly complementary and not competitive. This is particularly obvious in the additive manufacturing industry, where shot blasting and mass finishing go hand-in-hand for the post-processing of 3D-printed components. For example, shot blasting may be used for cleaning operations, such as de-powdering, and initial surface smoothing of the workpieces, whereas mass finishing is employed to further refine the work piece surface. If needed, mass finishing can even produce a high luster polish. Of course, mass finishing and shot blasting complement each other in other industries as well. But we also expect a lot of positive synergetic effects in the field of automation, particularly with regard to robotics, material handling and the digitization of surface treatment processes.

(?) MFN: What do you mean by digitization?

(!) C. H.: For us, digitization means the electronic monitoring of key process parameters in mass finishing and shot blasting operations. It also includes the cost management and predictive maintenance of the respective machinery.  This will enable our customers to maintain stable mass finishing and shot blasting processes and to quickly identify the potential for process improvements and cost savings.  We consider digitization to be extremely important for our customers. Therefore, we have bundled all our activities in this field under the slogan “Rösler Smart Solutions”.

(?) MFN: Thanks for enlightening us about the function of the Technology Management Department at Rösler and your company’s “Smart Solutions” approach. But how do mass finishing media and compounds fit into your technological strategy?

(!) C. H.: Without innovative consumables, mass finishing would never have become the leading technology for surface refinement it is today! There are many instances, where specially developed compounds and media have opened up entirely new surface finishing possibilities. 

(?) MFN: Can you give us some examples? 

(!) C. H.: With pleasure. For example, the development of non-abrasive high density porcelain media along with suitable grinding and polishing pastes was the basis for the amazing Rösler KeramoFinish® process that is used for creating functional and decorative surfaces on all kinds of components. For example, KeramoFinish reduces the surface roughness of air foils, including large fan blades, to Ra values of < 0.25 micron. This is achieved without compromising the layer of residual compressive stress created by a preceding shot peening operation! Or it creates surface roughness readings of Ra = 0.05 micron on the cylindrical rollers of roller bearings.  KeramoFinish is equally effective for creating attractive polished surfaces on consumer goods such as brass door knobs, cutlery, even on the blades of pruning shears.

(?) MFN: Are there similar success stories?

(!) C. H.: Today Rösler drag finishers and surface finishers are extensively used for placing the finishing touch on orthopedic implants like artificial knees and hips. This would not have become possible without our company developing a special plastic grinding media that creates an extremely fine pre-polish finish on the cobalt-chrome and titanium components.
Another success story is the cleaning and recycling of the mass finishing process water with centrifuges. This required the development of special recycling compounds that offer better dirt dispersing capabilities and produce less foam than regular compounds. Today more than 90 % of all mass finishing operations are run in recycling mode with centrifuges. This is a huge win for protecting our water resources and environmental sustainability. But it became only possible by the development of suitable recycling compounds.

(?) MFN: Can you tell us something about recent developments?

(!) C. H.: Yes, of course. But before I give you some examples, let me point out something else: In today’s industrial environment the demand for specialized media and compounds is actually increasing. The manufacturing industry must deal with rapid technological changes like the growing use of additive manufacturing for volume production of standard components, the demand for brand-new work pieces for E-mobility, the need for automated manufacturing cell concepts, growing pressures for environmental sustainability, etc. This forces our customers to review their entire manufacturing operation and look, among other things, for innovative, more cost-efficient surface finishing solutions. Naturally, they turn to us for help.

(?) MFN: How do these developments increase the need for specialized mass finishing consumables?

(!) C. H.: The customer surface finishing demands are becoming more specific, which can frequently not be met with our standard products. Special finishing solutions may have to be developed, which frequently requires the modification of existing or the creation of brand-new products.

(?) MFN: Please give us some examples.

(!) C. H.: Our customers are confronting us more and more with finishing tasks for workpieces with extremely complex geometrical shapes and difficult-to-reach internal passages. Even though our range of consumables comprises more than 15,000 different products, we have found that our standard media shapes pose a certain risk of lodging in such complex workpieces during the finishing process. Lodged media will not only impact the actual finishing results but can cause costly crashes at downstream assembly operation. Therefore, media lodging in the workpieces must be prevented completely! The prevention of media lodging in the workpieces is even more critical for automated processes. Automation means that our machines, along with the peripheral equipment, are running without human intervention. In other words, there is nobody who checks directly for lodged media and takes corrective action. Such problems are frequently handled by installing camera systems that detect workpieces with lodged media and automatically discharge them from the finishing system. But this is quite expensive.
Of course, a better approach is the prevention of media lodging in the workpieces altogether. Towards this goal Rösler, in co-operation with an external partner, developed a new ceramic media, called “MultiShape”. This unique product has rounded areas on all sides. It significantly reduces the risk of media lodging, particularly in case of complex workpieces with difficult-to-reach internal surface areas, including tight edges, notches and slits. Another advantage is that the MultiShape media maintains its extraordinary shape, even after extended use.

(?) MFN: And has this new media fulfilled your expectations?

(!) C. H.: Absolutely. In numerous customer applications it has proven to be highly effective. By the way, because of its unique geometry, the MultiShape media has been patented.

(?) MFN: Do you have any other new media developments?

(!) C. H.: Another recent development is a non-foaming plastic media. Mass finishing processes with plastic media frequently pose a problem with unwanted foam in the machine. This can drastically reduce the grinding effect of the media and prolong cycle times. Foam can also affect the separation of the finished workpieces from the media and can even cause problems with the process water cleaning system. This makes the handling of the finishing process rather difficult and can require substantial rework of the finished parts. A customer, operating 33 (!) Rösler mass finishing machines asked us to help him with this problem. With the newly developed non-foaming media, all the customer’s difficulties could be eliminated. The finishing results can now be consistently achieved within the prescribed cycle time, and the separation phase also works very well. The media switch has also greatly simplified the handling of the finishing process and completely eliminated the need for expensive rework. The non-foaming media turned out to be so effective that we decided to offer it across the board to all our customers.
Would you like me to describe another new development?
(?) MFN: Yes, by all means!

(!) C. H.: Over 90 % of all mass finishing applications are wet processes requiring the constant addition of water and compound. For this reason, the finished workpieces must undergo a drying process. Frequently, this takes place in dedicated driers filled with organic granules such as shredded corn cob or crushed nut shells. Unfortunately, these organic materials produce dust that can potentially contaminate the finished workpieces and the environment. In cases where such a dust contamination must be absolutely prevented, expensive mechanical dust collection systems have to be installed. Rösler has recently developed an anti-dust compound that drastically reduces the amount of residual dust on the work pieces and in the environment without affecting the drying performance. The compound, in the form of a liquid, can be easily dispensed into the drying media. Already, small amounts of anti-dust compound are effective over a period of several days, and it can be quickly replenished as needed, either manually with a spray bottle or with an automatic dosing pump. 

(?) MFN: What you told us is quite impressive....

(!) C. H.: These are just a few examples of new developments in the field of mass finishing consumables. Our experts at Rösler are adapting some of our standard media and compounds to specific customer requirements practically on a daily basis. And we expect this demand for specialized finishing solutions, be it in additive manufacturing, e-mobility, aerospace, medical engineering or any other industrial field, to grow rapidly. We feel that our company is uniquely qualified to meet these challenges: Since we develop and produce all our consumables and equipment in-house, we can quickly adapt our products to the customer demands and if needed, develop completely new products.

MFN thanks Christian Höhn for this interview!

For Information: 
Rösler Oberf lächentechnik GmbH
Vorstadt 1, 96190 Untermerzbach
Tel. +49.9533.924-802, Fax +49.9533.924-300
E-mail: d.hund@rosler.com