Cable manufacturers seeking elastic and non corrosive materials have long chosen stainless steel as a reliable metal. Choosing stainless steel is because of its cost-effectiveness and high tensile strength. Due to its durability and integrity retention, it is also the preferred choice.

However, precision applications require precision materials, which stainless steel cannot provide. Tungsten, as the industry's preferred material for manufacturing surgical robots, is rapidly becoming popular. This is because tungsten is more flexible and wear-resistant under the same size of stainless steel. In addition, the strength of tungsten is 30% higher than that of stainless steel.

Why is it tungsten?

Due to the characteristics of tungsten wire, cables can be used for a longer period of time and require minimal maintenance or replacement. Tungsten wire has excellent temperature resistance, strength, and flexibility. It is worth noting that it is one of the strongest materials discovered so far.
Tungsten also provides unparalleled flexibility, with radii as small as 1 millimeter. When you apply similar tight bending radii to stainless steel cables, they may fail due to multiple cycles of bending stress. Due to the inherent characteristics of tungsten wire rope, it has been proven to be more ductile, thus increasing the number of cycles compared to equivalent diameter and structural stainless steel cables.
Tungsten cable structure
Tungsten is one of the most flexible metals used in mechanical cable structures. The following are some common tungsten cables used for surgical robots.

19X19

This is one of the most common tungsten cable structures in surgical robots. This cable structure consists of 361 individual wires. Based on the diameter of the finished cable, the diameter of these filaments may be as small as 0.0005 inches. The reason why this surgical robot has such a common structure is its excellent flexibility and tensile strength.
Due to its flexibility and the number of wires, its tensile strength is lower than other equivalent diameter structures, but higher than stainless steel cables.

7X37

This structure has fewer wires than 19x19 and consists of 259 wires. Therefore, it is not as flexible as 19x19 or 7x49 with 343 wires. However, for some surgical robot applications, this flexibility is sufficient, and its tensile strength is higher, approximately 20% higher than the former.

8X19

This structure contains 201 wires, so it is not as flexible as a 7x37 or 19x19 structure. Due to the small number of filaments used in 8x19 tungsten wire cables, the wire diameter used is larger, so the fracture strength of this structure is slightly higher than that of the more flexible 7x37 and 19x19 structures of the same diameter.
This cable has excellent stiffness and moderate flexibility, combined with its excellent tensile strength, making it an ideal choice in the field of surgical robots.

7X49

Compared to 19x19 tungsten cables, the 7x49 structure containing 343 wires has the same flexibility and similar tensile strength. Due to the large number of filaments, engineers designing this structure must pay attention to bearing the inherent risks of this structure. Sava's engineers take special measures to control these conditions to produce the most functional tungsten cable.

19X37

This is another type of tungsten cable structure that provides the highest flexibility and lowest tensile strength among different structures. The 19x37 cable consists of 19 1x37 strands. Each 1x37 strand starts with 1x7 strands, then 1x19 strands, and finally forms a separate 1x37 strand. Subsequently, these 1x37 strands are twisted to form a 7x37, and ultimately a complete 19x37 cable is formed. This 703 wire and cable can use fine wires with diameters as small as 0.0005 inches.

Key points

Tungsten cables are currently the strongest and most flexible in the surgical robot market.
These cables have different structures, each providing unique characteristics and functions.
Cables with more wires are usually more flexible.
The most flexible tungsten wire cable is 19x37, which has 703 wires.