Ceramic Fiber Tools Made of High-Performance Ceramics for Optimal Deburring and Polishing Results on Surfaces, Edges, and Bores
Wherever workpieces require a special surface finish, ceramic fiber tools are usually the first choice. Here, high-performance ceramics meet components that must deliver top performance, especially in aerospace and automotive industries. Their unique properties far surpass those of conventional wire brushes or nylon brushes embedded with ceramic particles. For example, ceramic fiber brushes can be used to machine cross-holes and surfaces, while grinding pins are ideal for precise fine deburring.
These process-reliable deburring and polishing operations can be integrated into the complete machining of components, eliminating the need for manual rework. KEMPF, the deburring specialist from Reichenbach-Fils, is the exclusive distributor of these specialized deburring and polishing tooling solutions and now has extensive application expertise—from tiny titanium components to large engine blocks machined with Xebec ceramic.
To get straight to the point – no, ceramic fibers have nothing to do with ordinary stoneware and even less with a coffee cup. Rather, the material used is a "technical ceramic," which, unlike a coffee cup classified as utility ceramics, is sintered at high temperatures from Al2O3 aluminum oxide and a special binder, thereby acquiring its unique properties. The resulting oxide ceramic features high hardness (harder than steel) and is therefore ideally suited as a cutting material in metal cutting operations. Additionally, this type of ceramic is highly heat-resistant, dimensionally stable, and wear-resistant—making it an excellent choice for manufacturing deburring tools that can be used across a wide range of applications.
Since this material is particularly well-suited for polishing and grinding tasks, it is logical to combine the unique properties of high-performance ceramics into individual fibers and develop complete brush systems that far outperform conventional (metal or nylon) brushes. Because ceramic itself is very hard, yet the fiber rods remain flexible enough to conform to the workpiece surface, a uniform grinding effect is achieved, resulting in consistent and excellent polishing and grinding performance and thus producing uniform surface finishes. Furthermore, no secondary burr forms during machining, and no adhesion occurs due to the self-regenerating effect of the ceramic material. All of this leads to remarkable surface qualities (Ra and Rz values) that are difficult or impossible to achieve with other tooling solutions in metal cutting processes.
“Burrfree Straight Out of the Machine” – a Key Advantage for Any Series Production
The ceramic tooling solutions distributed by deburring specialist KEMPF, featuring the described Xebec ceramic fibers, can be applied to a wide range of machining operations. The consistent goal is to produce “burrfree straight out of the machine” and therefore to offer tooling solutions that can be integrated into the entire manufacturing process with the aim of completely eliminating manual deburring tasks. Especially for high-volume series components, the resulting (cost) benefits are significant.
At Schwab CNC in Rot am See, KEMPF enabled complete machine deburring for the series production of an actuator housing (steering gear housing) made of magnesium, exceeding the required quality standards. With an annual volume of 200,000 pieces, this was no easy task, as the necessary tooling solutions had not yet been used at Schwab CNC. In addition to the complex contours machined with the Back-Burr Cutter & Path deburring system, the flange surface and all contours on the underside of the component also had to be deburred. The ceramic fiber brush used for this, type BÜA11-CB40M with red fibers, ensures the desired uniform removal of the burr on the component.
Machine deburring with a ceramic fiber brush of the type BÜA11-CB40M with a diameter of 40 mm – this traces the entire component edge on the underside within seconds and deburrs it completely. Continuous robot loading ensures nearly 100% machine utilization. To guarantee consistent grinding performance across all parts, the brush overhang can be easily adjusted via a set screw on the aluminum sleeve, or a compensating holder can be used for automated wear compensation. Schwab CNC relies on a tool length adjustment of 0.0005 to 0.003 mm via R-parameter programming of the brush for this application.
Due to the unique properties of these ceramic fiber brushes, an average wear of 0.0005 mm per component allows for a tool life of well over 100,000 machining operations. To ensure consistent deburring performance, Schwab CNC additionally employs parameter programming of the brush length. In this process, the tool length of the brush is automatically reduced after each program cycle until the preset wear limit is reached. For this actuator housing (steering gear housing), the machine operator only needs to readjust the brush after 20,000 components. Manual deburring operations on this complex component have since been eliminated.
Left: After milling the aluminum die-cast cylinder heads, significant burr formation occurs primarily along the casting contours. This burr must be completely and reliably removed within the specified machining time.
Center: The previously used cup brush with abrasive nylon filaments failed to meet the requirements, resulting in residual burr remaining in series production.
Right: The result after using the Xebec ceramic fibers. The surface brush removed all burrs, the process speed was maintained, and the customer was more than satisfied.
Compared to conventional brush systems on the market, ceramic fibers also demonstrate their advantages. Corresponding comparative tests were conducted at an automotive supplier whose produced cylinder heads for a well-known sports car manufacturer still exhibited residual burrs in series production. The aluminum die-cast parts were dry machined on the exhaust side using a carbide insert cutting head for process reasons, which generated significant burrs toward the exhaust channels and on the casting outer contours that were supposed to be reliably removed by the process. However, with the previously used disc brush with abrasive nylon bristles SiC, it was not possible to remove the burr root at the desired process speed. Subsequently, the ceramic fiber brush type BÜA21-CB40M with white Xebec ceramic fibers and 40 mm diameter was also used in dry machining with cutting parameters n = 2,400 rpm, f = 4,000 mm/min, and ap = 1.00 mm. The results showed that the ceramic fiber brush achieved a significantly better deburring result with no secondary burrs formed. The desired process speed was also maintained.
An overview of the different brush types (colors) – different applications and materials naturally require different properties of the ceramic fibers used. The four colors serve solely as a distinguishing feature for the varying hardness levels and the resulting abrasiveness of the fibers.
Combination of PCD Milling Cutter and Ceramic Fiber Brush Reduced Machining Time by 30 Minutes
A company faced similar challenges with a component made of aluminum sand casting when tasked with deburring multiple milled pockets. The semicircular “camera mount” with a diameter of approximately 600 mm, designed for the optics industry, required several recesses for camera installation. The outer contour of the milled pocket, typical of casting profiles and undefined, needed to be fully deburred—a process that was not reliably achievable due to burrs formed during the creation of the recesses. To significantly optimize the entire process, the previously used solid carbide milling cutters, which produced excessively large burr roots, were replaced by PCD milling cutters from KEMPF. The standard KF 910 cutters with diameters of 14 mm and 20 mm, along with a custom PCD tool of 38 mm diameter, provided such effective preliminary machining that the ceramic fiber surface brush used for deburring the contours only had to remove minimal burrs. This not only reduced wear and thus extended the tool life of the ceramic fiber brush but also increased the durability of the PCD cutters by a multiple compared to the previously used solid carbide cutters. Since then, the camera mounts produced in medium-sized series have been manufactured 30 minutes faster using the optimized process and the newly implemented PCD cutters. Manual rework is no longer necessary, as all processes are executed by machine with consistent quality.
The milled pocket on the outside of the camera mount above the recess for the camera – to deburr the contour, the entire surface is simply machined with a ceramic fiber surface brush of medium abrasiveness (red), type BÜA11-CB25M. By using the KEMPF PKD standard milling cutter KF910, a burr-minimized milling process was also implemented, which significantly increases the tool life of both the milling cutter and the 25 mm diameter ceramic fiber brush.
Ceramic Fiber Tools Are Worthwhile Even for Small Series
Deburring operations also play an important role in small series production or even prototype manufacturing. Especially when machining highly precise components, the decisive factor is not quantity but solely the achieved quality of the machining. This is particularly true for components in the aerospace industry. In this field, Seiffer & Steiner Präzisionsteile GmbH in Lauffen am Neckar has made a name for itself beyond German borders, having co-developed a highly precise optical sensor part for satellites and taken on parts of the prototype manufacturing.
Since the highest precision and manufacturing quality are prerequisites here, fully automated and burr-free production was mandatory. However, for the machine deburring of numerous bores with partially asymmetrical and curved contours, as well as surface machining, Seiffer & Steiner relied on appropriate tooling solutions that had not been available until then.
A trade show visit to the Deburring Expo in Karlsruhe and the resulting initial contact with deburring specialist KEMPF from Reichenbach-Fils was set to change this sustainably. To produce the many surfaces, bores, and 3-D contours reliably and absolutely burr-free directly on the machine, among other tools, a variety of ceramic fiber tools were used. For example, all cross-holes were deburred with a ceramic Cross-Hole Brush. The specially designed brush uses the centrifugal force to press the flanks of the ceramic fibers against the bore wall, efficiently removing fine burrs up to 0.1 mm without damaging the bore. With different tool lengths, this solution can machine not only “standard” bores but also deep-hole bores up to 370 mm. For the surface of the mounting flange of the approximately 100 mm long component made of high-strength titanium, a surface brush with a diameter of 15 mm was used, which is ideally suited for deburring flat surfaces without creating excessive edge rounding. Various ceramic grinding pins with flexible shanks and special ceramic material heads provide the necessary finish, precisely performing the final fine deburring on contours and bores under 10 mm in diameter.
Side surface of the optical sensor component for satellites – clearly visible is the surface of the mounting flange machined with the most abrasive type of ceramic fiber brush (blue brush) BÜA32-CB15M. The small cross-holes at the left edge of the image were reliably deburred using a Cross-Hole Brush BÜCH-A33-7M (blue) with a diameter of 7 mm.
At the front face of the optical sensor component, the ceramic fiber surface brush BÜA32-CB15M was used to deburr all contours with sharp edges without creating a chamfer. The small cross-holes within the main bore were finely deburred using a flexible abrasive fiber stone of type BÜCH-PB-4B (blue) with a diameter of 4 mm.
7 Man-Hours Replaced by 2 Machine Hours
With a complete range of ceramic fiber tools, Binder GmbH - Apparate und Behälterbau in Crailsheim was able to optimize its production. The stainless steel processing company primarily manufactures pressure vessels for the food, chemical, cosmetics, and pharmaceutical industries and therefore must meet the highest standards in surface quality. The stainless steel vessel closures, which are made from a single piece and often contain numerous bores, cones, and grooves, must be completely burr-free and have a perfectly mirror-smooth surface for their later use. Since every milling cutter, especially on overlapping surfaces, leaves certain marks on the surface, these had previously been painstakingly removed by hand using various grinding and polishing attachments, which took about a full working day per closure lid (depending on size). Relief was finally provided by three ceramic fiber brushes that almost completely eliminated the manual work.
For surface machining (polishing and deburring of the workpiece edges), the most abrasive version of the brush type BÜA32-CB40M with a 40 mm diameter and blue ceramic fibers was used.
The milled cones were processed according to their angle using the ceramic mobile grinding fiber of type BÜA32-EB06M, also with blue ceramic fibers. This tool is ideally suited for machining the angled inner surface of the cones, as the contact surface is not flat like with other brushes but angled at approximately 50° (pointed).
Since the cones have different exit angles, the ceramic fiber wheel brush “WheelBrush” was additionally used at certain points. This tool is especially suitable when lateral surfaces need to be polished or deburred. Together with all three tooling solutions, Binder GmbH was able to shift nearly all production steps into the machine even for individual small series, standardize the processes, ensure quality, and exchange seven man-hours for only two additional machine hours in this machining operation.
It is evident that “ceramics” is one of the most versatile materials available. As the oldest man-made material in the world, ceramics have always played a role in human history and are now more in demand than ever as “technical ceramics,” as they have become part of the high-tech sector and continue to offer significant potential. In the field of machining, ceramics provide substantial advantages—such as higher material hardness compared to steel—yet they are still often underestimated. The examples presented demonstrate that tools made from ceramic fiber or ceramic stone deliver their benefits precisely when conventional tools reach their limits and components still require manual rework. As a deburring specialist, KEMPF provides the tooling solution that eliminates these unnecessary processes, saving customers time, money, and effort while optimizing production.
An overview of selected ceramic fiber brushes:
On the left, the smallest ceramic fiber brush of type BÜA13-EB01S “Mobile Abrasive Fiber” with a 1 mm diameter in pink. This brush is mainly used with portable devices for fine machining of small surfaces and edges.
Next to it, the ceramic fiber surface brush BÜA13-CB15M with a 15 mm diameter in pink, designed for machining small surfaces in the CNC machine.
The round brush of type “WheelBrush” BÜW-A11-75 with a 75 mm diameter is specifically intended for machining lateral surfaces and edges.
To the right, the blue ceramic fiber Cross-Hole Brush of type BÜCH-A33-7M with a 7 mm diameter, suitable for deburring cross-holes.
Far right, the ceramic fiber surface brush of type BÜA32-CB25M with a 25 mm diameter. This brush is especially suitable for somewhat larger surfaces. Diameters up to 200 mm are available for this brush type (XL).
The grinding pins with patented ceramic stone made of abrasive ceramic fiber material also take advantage of the unique properties and are ideal for deburring and polishing tasks. The versions shown in the image with flexible shanks additionally provide gentle and flexible contact with the workpiece, allowing for fine deburring without tool skipping, especially when machining cross-holes.