Surface finishing is a particularly important aspect when it comes to the manufacture of orthopaedic implants. Components such as hip femoral stems are subject to long-term cyclic loading, mechanical stress and the corrosive effects of body fluids, meaning that surface quality has a direct impact on performance, biocompatibility and reliability.
Traditional implant finishing can involve several separate stages, including manual belting, abrasive polishing, drag finishing and final manual buffing. While these methods are widely used, they can be labour-intensive, operator-dependent and inconsistent, especially with complex geometries. Not only this, but they can also introduce issues such as uneven material removal, edge rounding, defects in detailed areas and variation from batch to batch.
DLyte dry electropolishing offers an alternative approach. Rather than relying on conventional abrasion, the process uses solid electrolyte media and controlled electrical parameters to remove material by ion transport, selectively smoothing the peaks of the surface. This allows the surface roughness to be reduced while helping to preserve the original geometry of the part.
For femoral stem applications, DLyte has been used to target high-gloss, mirror-quality finishes with significant roughness reduction. Use cases have seen stainless-steel femoral stems go from an initial roughness of around 0.2 to 0.15 microns Ra, with the process targeting below 0.03 microns Ra.
A key advantage of the technology is its ability to produce homogeneous results across the whole component. Because material removal is electrochemical rather than purely mechanical, DLyte can avoid some of the limitations of abrasive processes, particularly where uneven media flow or high mechanical force can cause edge rounding or poor finishing in internal features.
In production terms, DLyte can also simplify the finishing route. The traditional process includes milling, manual belting, plastic media polishing, nutshell polishing and manual buffing. The DLyte process reduced this to milling, manual belting and DLyte finishing, or in some cases, go straight from milling to Dlyte. This reduction in process complexity can bring several benefits: shorter lead times, improved repeatability, reduced reliance on manual finishing, lower scrap and rework, and a smaller production footprint.
For medical manufacturers, another important point is surface integrity. Processing parts on DLyte leads to improved corrosion resistance, defect-free isotropic surfaces and proven biocompatibility of parts processed with the system. DLyte-processed products were tested according to UNE-EN-ISO 10993-5:2009 and considered non-cytotoxic and are now widely used in the medical sector worldwide.
As with any surface finishing process, results depend on the material, component geometry and pre-condition of the surface before treatment. For this reason, AGS recommends assessing representative components before confirming the most suitable process route. Ideally, customers should provide drawings or samples covering the smallest, largest and most difficult parts in the family, along with the current process, starting roughness, target finish and production volumes.
AGS works with DLyte to support UK manufacturers with application advice, sample testing and process development for demanding medical and precision finishing applications. For manufacturers producing implants, surgical instruments, needles, or other components requiring high-precision, DLyte offers a highly controlled route to improved surface finish, process repeatability and reduced dependence on manual polishing.
To discuss whether DLyte is suitable for your components, contact AGS with your drawings, material details and current finishing requirements.