High-precision medical machining

When it comes to the medical field, precision and reliability are crucial for producing high-quality biocompatible components. Kennametal’s TopSwiss™ line of tooling excels at meeting stringent requirements and close tolerances. This platform supports the development of cutting-edge medical technology, helping to improve the lives of those who rely on the latest medical innovations.
TopSwiss tooling features sharp cutting edges and aggressive geometries that create low cutting forces and excellent chip evacuation, ensuring longer tool life and superior surface finishes. The TopSwiss™ MBS (Micro Boring Solid) system is especially distinguished for its precision in machining extremely complex and small components.
“In regard to the TopSwiss MBS, especially for medical-grade applications, the tooling must be precise and reliable to manufacture components like bone screws, tulip heads, dental implants, and surgical instruments,” said Scott DeVinney, Senior Global Product Manager, Medical and Small Part Machining. “They have to meet the most stringent requirements for safety and compatibility with human tissue.”

Innovative Solutions
Finding the best results for customers is always a priority when designing the latest technology. When a prominent medical company is faced with the challenge of pinch-turning long instruments made of 17-4PH stainless steel, there is a struggle with tool life and chip control. To resolve this, the Kennametal team creatively adjusted parameters. They processed these instruments on Swiss-type turning machines using a standard TopSwiss ISO turning insert with advanced finishing wiper technology and a new coated cermet grade (KTP25S), designed specifically for Swiss-type turning. This resulted in excellent chip control and surface finish, and it increased tool life by 900%, from 50 to 500 pieces.
Additionally, a TopSwiss ISO turning insert with the new Light Finishing Swiss (LFS) geometry and grade KCP20S was used to enhance surface quality and chip control for a company needing a solution for turning PH stainless steel instruments. The TopSwiss tooling not only improved surface quality but also offered nearly 50% cost savings over the customer’s existing solution.

Advanced Coatings and Tool Holders 
The TopSwiss™ MBS platform contains micro boring inserts specifically designed for machining medical components. These inserts feature a specialised KCSM25S coating for a smooth, polished surface that reduces chip adhesion and improves component quality. The inserts also have a unique lead and relief angle that can withstand high tool pressure. Additionally, coolant is delivered directly through the tool to the cutting edge, reducing heat and improving chip control. For optimal performance, the inserts can be paired with HP (High Performance) tool holders, which offer high precision and repeatability to the centerline of ±5 microns.

Versatility and Customisation
Kennametal’s TopSwiss™ platform stands out for its versatility in handling a wide range of applications, with nearly 1,000 inserts available. This extensive selection allows for precise customisation to meet specific machining needs, whether it’s boring, profiling, back boring, grooving, threading or multi-directional turning.

Low Feed and Speed Applications
Highly effective in low feed and speed applications due to their superior chip evacuation, the TopSwiss™ ISO inserts ensure smooth operation by efficiently removing chips and preventing build-up. They provide excellent surface finishes and extended tool life, thanks to their precision and sharpness. With nose radii ranging from 0 (sharp) to 0.80mm and close tolerances (+0/-0.05mm), these inserts offer precise cutting capabilities.

Material-Specific Inserts
The ISO platform offers specialised inserts in both carbide and cermet grades. These inserts come in fine finishing, light finishing, parallel positive, and finishing wiper geometries. Carbide inserts can be used on steels, stainless steels, high-temperature alloys, and non-ferrous materials with grades such as KCS25S, KCM25S, KCP20S, and KN10S. Cermet inserts are designed for carbon steels, alloy steels, and stainless steels with the grade KTP25S.

The Importance of TopSwiss Cermet Wiper
Cermet is highly effective for machining applications that require high surface quality, dimensional stability, and tight tolerances. It is particularly suitable for high-speed finishing. Offering significant improvements in surface finish and productivity, the TopSwiss Cermet wiper insert features a secondary radius (rw) that follows the primary corner radius (r), effectively reducing the scallop height (Ra) and greatly enhancing surface roughness.

Key Advantages of Cermet Wiper Inserts

• Due to the larger size of the secondary radius, wiper inserts can achieve higher feed rates while still maintaining or even improving surface roughness. This results in increased productivity without compromising quality.
• Wiper inserts are most effective when used to activate features that enable the secondary radius to follow the corner radius. This includes straight lines, small angles, and chamfers. However, they are less effective on steep angles or chamfers, where the geometry does not allow the secondary radius to follow the corner radius.
  “When you’re using wiper inserts, it’s all about the details. Think about the lead angle and the specific feature you’re machining,” said DeVinney. “These details can make or break the effectiveness of the inserts. You must take the time to plan and set up carefully to achieve the best results.”
  To avoid workpiece damage, it’s crucial to select the appropriate material and machining speed and use coolant to prevent overheating. This can be achieved by adjusting cutting speeds, feed rates, and the depth of cut, ensuring proper coolant flow, and selecting the right cutting tools. Kennametal’s Swiss-type turning platform is the perfect solution to enhance efficiency and provides a cost-effective, versatile solution applicable to various materials.
  Kennametal’s TopSwiss™ platform stands out as a premier solution for precision turning. With its advanced tooling features, innovative solutions, specialised coatings, and material-specific inserts, TopSwiss™ ensures precise machining capabilities, particularly in the medical field.