Click ME to close the menu.

Log In to MTD Channels to access your customer cockpit and see content more relevent to you.

Seco Tools latest developments on the machining of ceramic implants

Seco Tools latest developments on the machining of ceramic implants

Added to MTDCNC by MTDCNC on 03 September 2013

Seco Tools reports on the latest developments concerning the machining of ceramic implants using conventional machine tools, laser technology and special cutting tools.

The average lifespan of metal medical implants depends on their use.

The more active the implant recipient is, the faster the implant will wear. In some instances, this can mean that an implant’s life is short…perhaps being only 10 years or so. For less active people an implant will last longer with 25 years (before a replacement is required) being possible.

This means that for younger recipients an initial implant might need to be replaced one or two times during their life which is not an attractive proposition considering that the rehabilitation period for orthopedic type operations such as knee and hip replacements, is quite painful and extensive.

It’s a different story with ceramic implants.

Lasting approximately 75 years (or even longer), ceramic implants provide a more satisfactory solution requiring the recipient to undergo only one surgery and a single recuperation period. Furthermore owing to ceramic implants’ high wear resistance and bio-compatibility there is less chance of an implant deteriorating ‘in situ’ – a particular problem associated with metal implants when they wear.

Unfortunately it’s not all plain sailing with ceramic implants otherwise they would be used much more widely than is currently the case.

The main problem that has dogged ceramic implants’ acceptance is one of cost (of manufacture) which makes these types of implant expensive and, in many instances, unaffordable.

In an effort to make ceramic implants more economically viable medical device precision component manufacturers, often working in conjunction with universities and research facilities, have explored and tested new and different manufacturing methods using conventional machine tools.

To date, one technique using laser technology looks promising.

The laser concept

The key elements of machining ceramic implants cost-effectively combining conventional machining methods with  laser technology involves using specially-designed cutting inserts and the mounting of a laser on a multi-tasking machine tool.

By precisely positioning the laser beam ahead of the cutting insert, the ceramic material is plasticized, making it easier to cut. Recent developments in cutting tool technology that are having a positive impact on machining ceramics include the use of polycrystalline diamond (PCD) and cubic boron nitride (CBN) inserts. CBN in particular is proven to have a strong potential in this area.

To date, laser assisted machining (using the specially-designed inserts) has made it possible to successfully turn, mill and thread ceramic materials such silicon nitride, zirconium and alumina.

Significantly by using the new process cutting tool life improved and machine processing times for these materials was reduced. A win:win situation.

Furthermore by using multi-axis machine tool technology, complex-shaped ceramic parts previously impossible to make using the more traditional (grinding) method for machining ceramic implants, were able to be produced.

It is early days still but these results are promising and, through further research into laser-assisted machining techniques, cutting tool edge preparations and the chemical interactions between cutting tools and specific ceramic materials, a better and more comprehensive understanding of the ceramic cutting process will be achieved.

It is estimated that if progress with the laser assisted machining continues at its current pace, it could well replace diamond wheel grinding as the preferred method for machining ceramics in the near future - in much the same way that hard turning replaced grinding twenty years ago.

 And while the method is in its infancy, a major milestone has been passed in the quest to reduce the cost of manufacturing medical implants from ceramics.

Building Location