Manufacturing Process Of EXPO-MED Surgical instruments manufacturing is based mainly on Hand skill work. The master craftsmen spend their lives to learn the art and then produce world class instruments. Expo-Med use the material in production is as under:
Raw Material
First stage is the selection of material for a particular item keeping in view the required specifications. As discussed in my first post majority of the surgical instruments are manufactured from different Stainless steel grades. These grades for particular range of instruments can be found in standards as given as under: German Stainless Steel 440A Japanese Stainless Steel AISI 320 French Stainless Steel Pakistani Stainless Steel HRC48-52 depends on the requirement of our customers and cutting of tools required.
More description of the material used is as under:
Stainless Steel The majority of Expo-Med Instruments are manufactured from “Stainless Steel”. Stainless steel is not truly stainless but rather a highly corrosion and rust-resistant alloy. The metal is extremely strong and durable and more importantly has a characteristic ability to form protective or from Passivation layers. Steel is composed primarily of iron. The other components are as follows: Carbon 0.17-0.25% Silicon £ 1.0% Manganese £ 1.0% Phosphorous £ 0.045% Sulphur £ 0.043% Chromium 12.0-14.0%
Stainless Steel Grade Magnetic Stainless Steels AISI 410 /410X: Used for Gripping Instruments like Forceps, Tweezers, Dressing forceps, retractors etc. AISI 420A : Used for Cutting instruments like Bone Rongeurs, Chisels, Gouges, scissors with carbide inserts and Needle Holders etc. AISI 420B: Used for High grade cutting instruments like Scissors, Bone Rongeurs etc. Non Magnetic Stainless Steel AISI 304: Used for Cannula, Clamps, Holders, Spreaders, suction tubes etc. Appropriate selection of the material helps in achieving the intended output of the manufacturing processes and the final required specifications. Care Instructions”, Section 12. A12
Tungsten Carbide
Tungsten carbide TC an alloy of tungsten and carbon is used in the manufacturing process of Expo-Med Instruments as needle holders, scissors, pin cutters, pliers and wire tightness mainly for Orthodontics. Since the TC is harder than the steel used in needles, pins and wires it results in instruments with exceptional durability. Usually the TC is soldered or welded to the jaws or working ends of instruments. TC inserts that are soldered can be separated from the instrument and replaced when they become worn. TC that is welded to the stainless steel cannot be separated, and therefore is not replaceable.
Titanium Titanium is becoming more widely used, particularly in the manufacture of implantation devices used to repair fractures, e.g., plates and screws. Titanium is an appealing choice for implants because of its proven biocompatibility. Titanium made instruments is of high cost
Manufacturing Stages: Manufacturing stages fallowed by Expo-Med Instruments for the production of Surgical Instruments are: 1) Forging: This is a simply a process for shaping metal parts through compressive forces either Hot or in Cold state. There are two types of forging processes involved in surgical instruments manufacturing i.e. Hand forging for small quantities orders and Hammer Forgings for bulk quantities.
2) Press work: After getting a crude shape impression in a piece of metal the excess material around that shape is cut off (trimmed) to get more desirable shape in the form of forgings. 3) Milling: Milling is a material removal process, which can create a variety of features on a part by cutting away the unwanted material by machining. Through milling, different features such as serrations, Ratchets, Male & Female box cuttings, different types of grooves etc. are produced in surgical instruments.
4) Grinding / Filing: These are material removing processes using different types of grinding wheels and files. This is a very critical stage in the instruments manufacturing because here the base for the general shape is produced using different types of gauges and the initial settings are done.
5) Heat Treatment: Heat treatment is done to change the instruments physical and mechanical properties without changing the original shape and size like “Annealing” is done to soften the material and “Hardening” is done to Produce Hardness and “Tempering” is done to produce toughness in the instruments. Thus heat treating is a very useful process to help other manufacturing processes and also improve product performance by increasing strength or provides other desirable characteristics
6) Chemical Treatment: The main purpose of chemical treatment is to clean the surface of the steel parts and if carried out properly, they all increase the corrosionresistance.The main processes used in the surgical instruments manufacturing includes:
7) Pickling It is usually done after the heat treatment process to remove the scale formed because of oxidation. Dilute Sulfuric Acid / Nitric Acid is used for this purpose. 8) Passivation The passivation is performed when free iron, oxide scale, rust, iron particles, metal chips adversely affect the stability of the surface. Passivation consists of immersing stainless steel instruments in a solution of nitric or citric acid and sodium dichromate, dissolving the imbedded iron particles and restoring the original corrosion-resistant surface by forming a thin, transparent oxide film.
9) Electro polishing
Passivation also is accomplished by electro polishing. Electro polishing is an electrochemical process that is a super passivator of stainless steel and results in a more passive surface than the other methods mentioned above. The metal, which is electro polished gives a bright surface and appearance of metal looks fine. The second advantage is that some burr is also removed in this process. Most commonly
phosphoric and sulphuric acids are used in conjunction with a high current density to clean and smooth (by metal removal) the surface of the steel.
10) Fixing: At this stage setting is done to align the instruments with proper functioning.
11) Hand Skilled Polishing: This is the most tough job and required a very professional staff. These are the metal finishing processes to produce different types of appearances like mirror or dull. Different abrasives are used on a work wheel to finalize the finish. Following are the types of polishing
This is Mirror Polish
This is Titanium Coated/Paper Coated There are so many other textures available
12) Ultrasonic Wash
This is Satin Finishing Polish
This is 24k Gold Plated
In this process we process the finished instruments in trays kept under scratch resistant surface in trays to give them top cleaned look and dirt off the instruments from any type of polishing material and dust particles or stains.
13) Final Inspection, Packing & Then Dispatch. While quality is a concern at all points of the manufacturing and crafting process, it is at this stage that we demand a final inspection which checks the functionality critical dimensions and surface conditions of the instrument. This inspection is performed by our manufacturers. The instruments are checked for desired specifications and sent for final inspection and testing before packing.