For manufacturing of surgical and dental instruments, MLINTRA first chooses the correct stainless steel grade for required instruments. MLINTRA takes the help of ASTM & DIN standards, DIN book, ISO's standard manual and other suitable literature for the manufacturing of surgical instruments.
For surgical instruments, mostly two types of stainless steels are used:-
• AUSTINITIC STAINLESS STEEL (AISI 300 Series) Non-Magnet.
• MARTENSITIC STAINLESS STEEL (AISI 400 Series) Magnet.
Mostly Martensitic stainless steel is used with AISI 410 & AISI 420 grades for the manufacturing of General Surgical Instruments.
Austenitic and Martensitic stainless steel are used for the manufacturing of Dental instruments.
AISI 410 Grade is used for manufacturing of NON-CUTTING Instruments.
AISI 420 Grade is used for the manufacturing of CUTTING Instruments.
AISI 304 is used for the manufacturing of the Tips of Scalars and Elevator Handles.
Other Stainless steel Grades are also used according to requirement of the instruments.
• Material shall conform to the mechanical property requirements as following:
Hardness Guidelines for Selected Class 4 Martensitic Stainless Steels in the Annealed Condition
Type Brinell Hardness
416 Mod 262
420 Mod 255
420F Mod 262
2. Corrosion Resistance
There are two test methods are specified for determining corrosion resistance
Copper Sulfate Resistance Test and Boiled Water Resistance Test.
A-Copper Sulfate Resistance Test
Check that there is No copper deposit on the instruments.
B-Boiled Water Resistance Test
Check that there is No blemishes on the instrument OR No visible signs of corrosion.
A-Function of needle holders & Haemostatic forceps
The function of needle holders shall be tested in accordance with the following:
Place a plastics fiber (e.g. a suture filament) of a maximum diameter 0.2mm between the jaws of the instrument at a point within the third of the length nearest the tip. Fully close the instrument and apply a tensile force of 20N to the fiber. Record whether the fiber is pulled out from the jaws.
After the test, no distortion, cracks or any other permanent modifications shall be visible.
B-Function of Haemostatic forceps
Place a test wire in accordance with table 1 or 2 as appropriate between the tips of the instrument jaws. Fully close the instrument to the last ratchets position. Leave the instrument in this position for 3 h at room temperature. Examine the instrument for the presence of cracks and permanent deformation.
4. Cutting (for cutting instruments)
The cutting ability of the instruments shall be tested in accordance with the following:
The testing material in accordance with the table shall be cut non-stop three times along two-third of the blade without lateral pressure.
• The testing material shall be cut cleanly without tearing.
• After the test, no distortion, cracks or any other permanent modifications of the instrument shall be visible.
5. Visual Inspection
All Instruments should pass the following inspections:
• The instruments shall have joints which move smoothly and shall be neither too loose nor too tight; it shall be possible to close and reopen the instruments easily with two fingers.
• All surfaces shall be free from pores, crevices and grinding marks. The instrument shall be supplied free from residual scale, acid, grease and grinding and polishing materials. Compliance with these requirements shall be checked by inspection under normal vision, corrected, if necessary.
• Check the instruments marking with Life Care trade mark & Code of the instruments.
• Instruments having tungsten carbide inserts shall have gold-colored handles.
• Check the instruments dimensions according to Catalogue.
6. Storage and sterilization
Be sure that warranty & instructions are properly sterilized.
• The packing design should be fulfill protected of each instrument against damage and deterioration.