Minimal burr drilling without a cap – where manual deburring was once necessary, components now come #burrfree straight out of the machine
Manufacturers are constantly seeking ways to make component production more efficient and cost-effective while maintaining or improving quality. However, no one expected that simply switching the drill at TRIES GmbH & Co. KG in Ehingen an der Donau would completely transform the entire production process. After switching to the ExBurrDrill from deburring specialist KEMPF, based in Reichenbach-Fils, not only did drilling quality improve, but tool life increased tenfold and extensive deburring efforts were eliminated.
Quality has been a top priority since the founding of the engineering firm Manfred Tries in 1964. This focus led to the development and integration of in-house production alongside the design of hydraulic components. In 1978, the current TRIES GmbH & Co. KG was established, now employing nearly 180 people and internationally recognized for its hydraulic control blocks, valves, and cylinders. As in the past, the company continues to specialize in the development and design of custom solutions in close collaboration with its customers. As a result, production volumes at TRIES range from single units to tens of thousands of parts per year, primarily used in special-purpose vehicles, wheeled excavators, and cranes from well-known manufacturers.
High effort for a standard component
When producing a turned part with cross bores for hydraulic blocks, measuring only about 120 mm in length and with an annual volume of around 25,000 units—a standard product at TRIES—the seemingly “simple” drilling operation turned out to be a real bottleneck in the entire machining process. The drills used generated significant burr formation at the bore exit inside the part, requiring manual deburring as a first step, followed by thermal deburring by an external service provider. Additionally, the short tool life of the drills led to unreliable process reliability, as burr formation had to be constantly monitored, and the drills needed replacing after just about 2,000 bores. This production workflow was unacceptable to Robert König, Head of Serial Production, prompting a search for a new and better solution.
The steel hydraulic housing clamped in the CNC machine. The ExBurrDrill with TiAlN coating (diameter 5 mm, Z=3) drills four holes in the part within a few seconds, without the need for subsequent deburring. The component comes out of the machine finished and already #burrfree.
A small drill makes a big difference
After multiple trials with drills from well-known manufacturers failed to produce satisfactory results regarding burr height at the bore exit, TRIES discovered the ExBurrDrill from KEMPF. This minimal-burr drill, developed by the deburring specialist, also ensures that no drill caps remain on the part due to its special geometry. With the support of KEMPF's field representative Thomas Welte, the drill was quickly tested at TRIES.
The component on the right and the cross-sectioned version for analysis on the left. Clearly visible are the complete bore and the two cross-sectioned bores (on the left part). The bore diameter is 5 mm, and the inner diameter of the main bore at this position is 14 mm.
Although expectations at TRIES were modest due to prior failed attempts—and simply eliminating the need for external thermal deburring would have been considered a success—the performance of the ExBurrDrill exceeded all expectations. Once implemented on several machines, burr formation at the bore exit was undetectable or barely measurable even after thousands of bores. Now running in continuous production, the performance is so consistent that no inspection is needed; the drill is replaced preventively after about 20,000 parts to preclude possible burr formation.
The bore exit inside the workpiece, shown in close-up, was created after approximately 4,000 bores using the ExBurrDrill. No burrs are visible.
Performance boost and production optimization
Since implementing the KEMPF ExBurrDrill, bore exits no longer require post-processing. Continuous inspection and machine downtimes due to tool changes are also a thing of the past.
Robert König, Head of Serial Production, is enthusiastic: “After the first successful application of the ExBurrDrill, we now use the drill for other components in three different diameters. In some cases, the drill performs up to eight bores per part—and even in these cases, burr formation is no longer an issue.”
Left: Thomas Welte, technical field representative of deburring specialist KEMPF GmbH; right: Robert König, head of serial production at TRIES GmbH & Co. KG, in front of the machine where approximately 25,000 parts are produced annually with the ExBurrDrill.
Engineered for minimal burr at maximum feed rate
The KEMPF ExBurrDrill offers additional advantages that significantly improve machining processes compared to standard drills. To unlock its full potential, this specialized drill is not offered as an off-the-shelf product but is custom-manufactured for specific customer applications in diameters ranging from 0.8 mm to 20 mm. The drill geometry is parametrically adapted based on the bore exit engagement conditions and the component's material.
Custom tool manufacturing enables the combination of multiple process steps into a single drilling operation. By using a step drill, for instance, both the subsequent deburring process and a countersinking or reaming process can be eliminated. This reduces tool change times as well as cycle times on the machine.
In principle, the KEMPF ExBurrDrill was designed to drill with minimal burr formation, ideally at higher feed rates than standard drills, and without leaving drill caps that pose risks to downstream tools. The ExBurrDrill’s special cutting geometry eliminates this risk. If edge breaking is required on the part, subsequent deburring tools are significantly relieved due to the minimal residual burr. If the bore is ECM-deburred, the process runs with significantly fewer disruptions thanks to the much smaller residual burr.