Electrical Discharge Machining (EDM) increases automation and precision in orthopedic manufacturing

When manufacturing products for the orthopedic market, precision is of the greatest importance. The right combination of technology and automation can ensure this precision, while reducing production costs and increasing capacity at the same time. At Onyx Medical, we believe it is important to develop our skills and knowledge in order to meet our customers’ needs. In this article, I’d like to share one way we are doing that with an EDM machine that enables us to create perfectly straight holes in our cannulated drills – faster, and at a lower cost, than other techniques.

Orthopedic instruments that require high-precision drilling

A cannulated drill is an example of an orthopedic product that requires extreme manufacturing precision. Used in fixation surgeries for fractured bones, the drill has small-diameter hole through which a guide wire is inserted, which is used to drill a small guide hole in the bone where a tunnel or screw hole is required.

The advantage of this process is that the guide wire can be repositioned without causing undue trauma to the bone. When the position is right, the cannulated drill is driven along the guide wire to drill the actual hole into the bone. This way of working makes for a more precise surgery, provided that the guide hole in the cannulated drill is perfectly straight. If it is not, the guide wire might move off of position while drilling.

Comparing gun drilling vs EDM for the creation of perfectly straight holes

One way of creating holes in orthopedic instruments is gun drilling. The gun drilling process uses a single fluent drill held stationary or slightly rotated. The drill has a high-pressure coolant that runs through the center and removes chips and lubricates the drill. A challenge with gun drilling is that when drilling long holes, the drill can drift somewhat sideways. So, as the drill exits the workpiece, it will come out slightly off center.

Another method of creating a perfectly straight hole in a cannulated drill is electrical discharge machining (EDM). This method uses the effects of rapidly recurring electrical discharges between electrodes and the drill. The discharges create sparks that erode small parts of the material from the item, in this case, the cannulated drill. The cannulated drill is positioned vertically to the EDM machine and the sparks from the electrode reach the center of the drill and erode a uniform diameter hole all the way through its center.

An EDM machine makes it possible to create smaller, longer and straighter holes than with gun drilling. The holes can be as small as 0.8 millimeters in diameter and up to 200 millimeters in length.

Automated manufacturing for reliable results and reduced production costs

The EDM machine is also highly automated. Once the cannulated drills are loaded, the machine does the rest, changing electrodes and positions automatically. This reduces human operator time and ensures more consistent and reliable results. The key role of the human operator is to position the cannulated drills correctly, and exactly vertical to the machine. Once that is accomplished, the EDM machine produces straight, centered holes every time.

Elos Medtech continuously seeks to drive innovation forward and enhance our technical knowledge and skills in order to meet the demands of the market. Onyx Medical’s investment in an EDM machine in 2017 contributes to this goal. During our process of validating the machine, we have developed solutions and routines that perfect its performance. We have also designed and tested a variety of different fixtures to make it easy to load the machine with cannulated drills.

We are closing in on a solution that makes it possible to load the machine at the beginning of the day, after which it will run smoothly on its own for the rest of the day. The operator then unloads the completed parts, loads the machine with new parts and presses “go” again. This process produces reliable and high-precision results, reduced production costs and higher capacity.

I hope you enjoyed reading my blog article about our new EDM machine at Onyx Medical. Feel free to contact me with questions, or visit our website for more information. Also, don’t forget to visit Elos Medtech on social media and Elos Medtech’s knowledge blog for more interesting articles.

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