Method of obtaining products

FIELD: medicine.

SUBSTANCE: invention relates to method of obtaining products from titanium-based material with coating, representing semi-spherical head of medical semi-spherical cutter. Workpiece from unalloyed titanium is made by cold sheet-stamping stamping and drilling holes with countersinking. Hole centres are placed on two spiral lines with left approach, converging in dome, with obtaining semi-spherical head of medical cutter. External head surface is polished to roughness Ra not more than 0.1 mcm and cutting elements are made by flanging sharpened edges from left side of holes outwards and their sharpening. Nitration with vacuum ion-plasma method to the depth not less than 50 mcm is carried out. Titanium nitrade TiN layers are precipitated until total thickness of said layers is 4-7 mcm with microhardness more than 7000 MPa.

EFFECT: high cutting properties of semi-spherical head of medical cutter and its wear resistance are ensured with preservation of corrosion resistance and biological inertness.

1 dwg, 1 ex

 

The invention relates to a method of obtaining products of titanium alloy, representing a hemispherical head medical hemispherical cutter for the development of the acetabulum of the pelvis prior to installation of the appropriate implant and designed for continuous use in aggressive biological environments. The main component of the cutter is cutting thin-walled hemispherical head, on the outer side of which is by flanging shaped cutting elements.

Often hemispherical head medical cutters are made of stainless thermally hardening of steel by stamping (see, for example, "Waldemar Link", "Implants", product catalog, 2000, "Plus Orthopedics", "Implants for Orthopaedics and traumatology", catalogue of VNIMI, De Puy ASR International, "Surgical technique", 2000, No. 9998-90-173). For the manufacture of the cutting head stainless steel sheet material is subjected to hot forging and subsequent quenching. Occurring during hardening deformation changes cause a violation of the geometric parameters of the cutter, which reduces its dimensional accuracy. In addition, the heat treatment results in changes to the composition of the steel in the surface layer and, consequently, to decrease its corrosion resistance, and cutting edges to increased fragility that m which can lead to cracking and fracture of the head.

As the prototype accepted "Way of obtaining products from titanium alloys and products obtained by this method (variants)", RF Patent №2338811, in accordance with which products, including medical devices, is obtained from the pseudo-α or low-alloy (α+β) titanium alloy, comprising the manufacture of the workpiece, the polishing, the nitriding vacuum ion-plasma method to a depth of not less than 50 μm, and the deposition of layers of titanium nitride TiN condensation method.

However, to get a thin-walled workpiece milling heads of these titanium alloys by cold sheet metal forming is impossible due to their low ductility (δ=5-10%).

The optimal state of the metal thin-walled hemispherical head medical cutters is high plasticity her inner region and a hardened surface layer.

The present invention is to provide high cutting properties of the hemispherical head of the medical cutters and wear resistance while maintaining corrosion resistance and biological inertness.

The technical result is the performance and reliability of medical cutters due to the exclusion of brittle fracture of its hemispherical head.

The problem is solved due to the fact that the method of obtaining medical cutters of the material on the basis of titans coating, includes the manufacture of the workpiece, the polishing, the nitriding vacuum ion-plasma method to a depth of not less than 50 μm and the deposition of layers of titanium nitride TiN condensation method is used for the procurement of unalloyed titanium by cold stamping and drilling holes with a countersink and hole centers have two helical lines with the left approach, converging in the dome, getting a hemispherical head medical cutters, after which the outer surface of the head is polished to a roughness Ranot more than 0.1 μm and perform cutting elements by flanging pointed edges on the left side of the hole to the outside and sharpening, and the deposition of layers of titanium nitride TiN is carried out to obtain the total thickness of these layers 4-7 microns with a hardness of more than 7000 MPa.

Sheet unalloyed titanium grades VT1, VT1-0 has a high plasticity (δ over 30 - 55%), which makes it suitable for cold forming hemispherical billet head medical cutters. The resulting workpiece is cut off at the calculated diameter according to the size of the cutter, and then using the template on the surface of the workpiece is performed by drilling holes with a reamer. Hole centers have two helical lines with the left approach, converging in the dome, i.e. back in the direction of the milling of the acetabulum to avoid her through the passage, that can lead to patient injury.

The external surface of the billet heads with holes is subjected to grinding and polishing to obtain a roughness Ranot more than 0.1 μm to reduce the skid resistance of the free surface of the head of the bone when it is processed.

After flanging pointed edges and forming the cutting elements of the cutter head is subjected to nitriding at a temperature of 560-600°C for 40-60 minutes until the thickness of the hardened layer is more than 50 μm. To enhance the effect of hardening after nitriding optionally form a coating of 4 layers of titanium nitride TiN by plasma deposition from the vapor phase at a temperature of 400-420°C total thickness of 4-7 microns with a hardness of more than 7000 MPa.

The drawing shows the milling head on a spherical surface which made cutting elements (1), arranged in two helical lines (2) with the left approach, converging on the dome cutters. Milling is carried out by arrow (3).

Manufacturing process flow head medical cutters is as follows.

Fabrication of hemispherical billet head cutter carried out by the method of cold forming of sheet thickness of 1 mm of unalloyed titanium (grades VT1, VT1-0) and the crop on the estimated diameter of the hemisphere corresponding t the PA size cutters. The kit includes 11 types of sizes of cutters from 40 to 60 mm, Then on the surface of the workpiece using templates carry out the holes with a reamer with a diameter of 4 mm with the sharpening of the edges with the inner surface of the workpiece along two helical lines with the left approach, converging to the dome. Drilled workpiece is ground and polished to obtain a surface roughness Raless than 0.1 microns. The next operation is flared edges out using a special tool to a height of 1 mm from the left edge of the holes and pre-sharpening cutting edges protruding. Honed milling head is subjected to a preliminary surface hardening by means of vacuum ion-plasma nitriding at a temperature of 560-600°C for 40-60 min, after which the microhardness of the surface amounted to 5500 MPa. The final operation is the deposition on the nitrided surface of the head at a temperature of 400-420°With 4 layers of titanium nitride with a total thickness of 4-7 μm, which further increases the surface microhardness, which is not less than 7000 MPa.

An example of performing the method.

The milling head is made of cold rolled sheet, titanium grade VT1 thickness of 1.0 mm by cold stamping. After running the holes according to the technology described above, the cylinder is polished to sherokhovatost the surface R a=0,08 μm to form cutting edges. Hardening of the workpiece is performed by the method of ion-plasma nitriding at a temperature of 560°C for 50 min and then applying 4 layers of titanium nitride with a total thickness of 5 μm at a temperature of 400°C. After processing, the surface microhardness was 7800 MPa.

Wear a medical of the cutter head, treated under the proposed method, with a diameter of 56 mm was determined according to GOST 28684. As the test showed, during the cutting process on the plates of the PCB efficiency of the cutter and the radius of the blunting of the cutting edges has not changed. The ultimate state of one of the cutters 5 was achieved only after 52 cycles of testing, which indicates their high wear resistance and high cutting properties.

High corrosion resistance and biological inertness of titanium alloys are well known and greatly exceeds the corrosion resistance of stainless steels when working in corrosive environments, including the human body.

The titanium medical kits cutter heads, processed by the proposed method and the developed design submitted for testing in cyto them. Neprehrava in the Department of bone pathology. Within 9 months of use cutters found no deterioration in their health and traces to which Rosie.

Thus, the use of a hemispherical head medical cutters of unalloyed surface-hardened titanium processed by the proposed method and the claimed design ensures high cutting properties, corrosion resistance and biological inertness, as well as enhanced security in the processing of the acetabulum.

The method of obtaining medical cutters from a material based on titanium coated, including the manufacturing of the workpiece, the polishing, the nitriding vacuum ion-plasma method to a depth of not less than 50 μm and the deposition of layers of titanium nitride TiN condensation method, characterized in that is used for the procurement of unalloyed titanium by cold stamping and drilling holes with a countersink and hole centers have two helical lines with the left approach, converging in the dome, getting a hemispherical head medical cutters, after which the outer surface of the head is polished to a roughness Ranot more than 0.1 μm and perform cutting elements by flanging pointed edges on the left side of the hole to the outside and sharpening, and the deposition of layers of titanium nitride TiN is carried out to obtain the total thickness of these layers 4-7 microns with a hardness of more than 7000 MPa.



 

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5 cl, 2 tbl, 2 ex

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2 cl, 1 dwg

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12 cl, 3 tbl, 4 dwg

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EFFECT: increased functionality of cutting tool and quality of processing.

1 tbl, 1 ex

FIELD: metallurgy.

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EFFECT: increased functionality of cutting tool and quality of processing.

1 tbl, 1 ex

FIELD: medicine.

SUBSTANCE: invention refers to medicine, namely traumatology and orthopaedics. Injured finger flexor tendons are replaced within a fibrous synovial canal. For the purpose of the plastics, a graft made of a xenopericardial plate in the form of a twisted cylinder with cuffs on its ends and with ligatures along its length is used. The graft is attached to the tendon by ligaturing the graft inside the tendon stem; the ligatures are exteriorised on an external surface and tied together. A suture area is covered and reinforced with the cuffs to be anchored by separate interrupted suturing.

EFFECT: method provides adequate recovery of the lost function of the finger flexor tendons, prevention of potential complications, reduced injures.

4 dwg

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