Automated Deburring Made Simple

With its X-Bores series of deburring tools, Switzerland-based Heule has developed solutions for the automated deburring of cross bores.

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Deburring of cross bores can be a challenging task, especially in series production. Chemical deburring and common mechanical deburring strategies often require extensive secondary operations outside the machining center, especially where complex geometries and several cross bores leading into one main bore are involved.

With its X-Bores series of deburring tools, Switzerland-based Heule has developed solutions for the automated deburring of cross bores. The COFA-X, Snap-X, Cofa or cross bore deburring tool (CBD) can be integrated into a machine tool’s magazine and enable complete machining in one setup with defined cutting edges, the company says.

Deburring of Intersecting Bores with Identical Diameters

Cross bores with almost identical diameters show a very steep unevenness. According to Heule, this condition—the shape of the intersection—has made it impossible to deburr such cross bores mechanically so far. Starting with bore diameters of 4 mm and larger, the Cofa-X deburring tool (which is based on the standard COFA system and features an exchangeable carbide blade) radially removes the burrs off the bore edges, without requiring the workpiece to be turned or the spindle stopped.

In comparison with the standard system, Cofa-X possesses a pre-loaded blade, and the tip of the tool body shows a recess. This recess is necessary in order to enter the bore with an offset so that the blade does not suffer, the company explains. The Cofa-X system removes the burrs from interior uneven bore edges in applications with large intersections. It is designed to handle three types of bores: those with an identical or nearly identical diameter crossing each other; bores that merge into one another; and crossing bores with offset centers.

This system is effective on fittings, hydraulic manifolds, and other components with 1-to-1 ratio of holes.

Deburring Cross Bores Through the Main Bore

Another challenge shops are faced with are cross bores with various diameters leading into a main bore in different angles. Using modified deep boring tools, for instance, can lead to good results, but very often a 100 percent inspection process is necessary to make sure the burrs are all eliminated and not pushed back into the cross bores when the deep boring tool penetrates through the main bore. 

Heule’s Snap-X main bore tool deburrs the cross bores by penetrating through the main bore in one single pass. Several cross bores are machined right at the burr base. The radially supported and spring-loaded Snap-X blade is built with a clockwise and an anti-clockwise working cutting edge. Its form is convex and adapted to the cross bore. It enters the cross bore to the extent limited by the radius of the blade edge and the blade length. When the blade is working its way out of the cross bore again, it carries out the deburring in a skinning way of cutting.

Process Steps

With the spindle stopped, the tool head is moved 0.5 mm ahead of the main bore entrance in rapid traverse. In work feed, the tool is inserted into the main bore and moved to the first cross bore in rapid traverse. With clockwise rotation all intersecting bores are deburred in one single pass. The blade is kept movable in the tool body via a control bolt held under spring pressure. The blade has a special ramp-shaped recess where the control bolt engages in. While machining, the bolt glides up the ramp and increases the pressure on the blade, which brings the blade back to the starting position when exiting the bore again. In order to assure the best possible deburring result, the spindle rotation is switched to anti-clockwise rotation and all cross bores are machined a second time on the tool’s way out of the main bore.

Heule Tool Corporation | 513-860-9900 |