(1)In order to facilitate the drilling operation, and to reduce drilling costs, other manufacturers use high sulphur “free cutting grade” of stainless steel conforming to AISI 420 F. This raw material has numerous deficiencies, including reduced ductility and corrosion resistance. Our drilled needles on the other hand, are made from the same grade of surgical stainless steel as the highest quality surgical instruments. The raw material for these needles is martensitic grade stainless steel conforming to DIN Werkstoffnummer 1.4031. In the case of ophthalmic & certain specialty needles, maraging grade to AISI 455 is used.

(2)Other manufacturers anneal the drilled end of the needle to eliminate cracking during the swaging operation, which is a common problem with free cutting grade of steels. Our needles are uniformly hardened and tempered to a controlled hardness of VPN 525 to 625, which ensures adequate stiffness to withstand the pressure encountered in the suturing procedure while eliminating brittleness.

(3)Annealing of the drilled end results in discontinuous grain structure, which impairs the strength and corrosion resistance of the needle. In our drilled needle, since the drilled end is uniformly hardened with the body of the needle, the metallurgy and micro-structure of the needle is uniform.

(4)A further advantage of the drilled end being hardened is the better suture grip obtained after swaging. Though this requires higher swaging force, this results in higher pull-out strength than is possible with annealed end needles.

(5)Barber drilled needles are drilled with a funnel shaped counter-bore, which not only facilitates suture insertion during the swaging operation, but also obviates the possibility of suture “cut-through” during swaging.

(6)The outer side of the drilled end of the needle is also chamfered to eliminate any sharp edges at the swaged end.

(7)The raw material is also of a restricted specification grade with carbon controlled to 0.32 % minimum and Chromium 12.5 % minimum. Though the restricted specification adds considerably to the cost of raw material, as well as to the processing cost, the resulting product combines high stiffness with high ductility. Due to this, a drilled needle will withstand bending through a sharp 90 degree angle without breaking.

(8)The needles are polished to minimise micro asperities on the surface by a series of mechanical polishing operations followed by electro polishing. This reduces tissue drag during the suturing operation to a minimum.

(9)We have a unique point geometry for cutting edge needles, which has a convex curved profile from the tip of the point to the widest part of the point. This combines the advantage of the higher effective point angle right at the tip, which is strong and resistant to feathering, with a progressively reducing angle towards the widest part of the point. This gives excellent penetration characteristics. The point grinding is done on special purpose machines to ensure consistency.

(10) A strict Quality Control protocol is followed at each stage of the manufacture. The tests include sharpness testing, which is done on a specially designed digital sharpness comparator, which measures the force in grams required for penetrating a diaphragm made of polyurethane standardised synthetic material, which mimics the characteristics of skin. The stiffness of the needles is also measured with a special digital tester which enables the force vs displacement of the needle to be plotted, and which also determines whether the needle has regained its original shape without any permanent set.

(11) Drilled needles can optionally be offered with a ribbed body to increase the stiffness and improve the stability in the needle holder.

(12) Drilled needles can also be offered with a silicone coating, which is a polysilaxane coating with Dow Corning MDX4- 4159 grade silicone, duly cured to give a stable lubricant coating which considerably improves the penetration characteristics.