2/28/2020 | 2 MINUTE READ

Debunking the Deburring Process

Facebook Share Icon LinkedIn Share Icon Twitter Share Icon Share by EMail icon Print Icon

A car manufacturer struggled with a complex and unreliable deburring process for its crank case production line until it was introduced to a tool designed specifically for cross bore deburring.


Facebook Share Icon LinkedIn Share Icon Twitter Share Icon Share by EMail icon Print Icon

Connect at

HEULE Precision Tools will be exhibiting new technology at IMTS 2020 in Chicago this September.

Plan to meet up with their team or get registered here!

A German car manufacturer recently found itself in a cranky mood regarding its crank case production line. Though everything else in the line was humming along, deburring cross holes in the crank shafts required a complex and unreliable process that was grinding away its production time, not the leftover burrs.

Crank Case Deburring

The crank case has five cross-bore oil holes (red) that intersect with the main bore hole (yellow). The unevenness caused by the geometric conditions at the points where the bore holes intersect ruled out the use of conventional deburring tools.

Many machinists have found themselves in a similar situation—deburring cross holes is a stubborn problem requiring multiple pass-throughs that still don’t get the job done. The car manufacturer used two deep-hole drills and drove through the boreholes 8 to 10 times each. Despite repeated deburring, burrs remained and required visual inspection and reworking. At 1.4 million components per year across five production lines, each extra pass to deburr adds up quickly.

Finding a Solution

The manufacturer’s head of technology went to the AMB trade fair in Stuttgart to discuss the problem with Heule, a leading producer of deburring tools. The head of technology knew the supplier from a previous deburring project and knew the company could offer a tailored solution to the cross-hole problem.


The solution was a deburring tool based on COFA-X, tailored to the specific application like all cross-bore deburring tools. It is suitable for all intersecting bore holes up to 1:1.


Cross Hole

The intersection of the cross bore (6.4-mm diameter) with the main bore hole (11.6-mm diameter) caused a large unevenness with an eccentricity of 1.9 mm.

Not only was deburring, itself, a complicated process, but the car manufacturer had specific needs that made the process even more nuanced. The intersection of the cross bore (6.4-mm diameter) with the main bore hole (11.6-mm diameter) caused a large unevenness with an eccentricity of 1.9 mm. Conventional deburring solutions and standard products available at the time just weren’t up to the task.

Heule worked with the car manufacturer to create a product that would suit its needs. The first solution proposed had a large control housing that the manufacturer didn’t have the space for in its facility. Heule went back to the drawing board and came back to the manufacturer with the COFA-X, a revision of its COFA tool designed especially for cross bore deburring.

After months of testing and communications back and forth, the car manufacturer commissioned Heule to repeat in its production plant the successes it had in the development laboratory. By the third run, the automated deburring process was corrected and optimized to perform the task without error.


The quality officer visually inspected the chamber using an endoscope and confirmed the result: “No burrs.” The quality of the deburred surface was even better than before. The manufacturer was ready to get the production line back up and running for mass production.


Deburred Hole

The arrow indicates the burrs on the unprocessed borehole (left). The new tool removes burrs in a mechanically defined, more reliable way, shown on the processed borehole on the right.

Cross bore deburring, a process that once took 8 to 10 passes and then even more fine tuning, can now be done in one pass with one tool and one operator. Heule’s initial testing showed that each COFA-X could process about 7,000 boreholes, allowing the manufacturer to deburr the crank shafts more reliably and with less tool downtime than before. The results had the car manufacturer feeling a lot less cranky, thanks to the COFA-X.

Heule Precision Tooling | 513-860-9900 | heuletool.com


  • A Standard Approach to Classifying Burrs

    Variations in the definition of a burr created problems for shops trying to provide deburring solutions and for customers trying to figure out what solutions to look for.

  • Finding Faster Deburring

    While attending a trade show in the fall of 2000, a research and development employee at Upchurch Scientific (Oak Harbor, Washington) saw a magnetic deburring and polishing machine. It was well known throughout Upchurch that manual deburring was very labor intensive, so he took note of it.

  • Robotic Deburring Provides Flexible Alternative

    The consistent performance and radial compliance of this device is making companies re-evaluate their manual deburring operations.