Filaments are a vital part of additive manufacturing. It is the main source in FDM printing. As there is rapid growth in industry, the filaments are available in a variety of sizes, brands, materials. The process consists of five steps. Now let us know in detail how the filament is made.
Step 1: Plastic – The first step in manufacturing filament is the preparation of plastic. Crude oil is heated in an industrial furnace during refinement. Main component is naphtha, which is chemically bonded in the reactor. Finally the products are melted and mixed with other products to form plastic. Then the resulting product is known as pellets or resin. Usually plastic suppliers manufacture plastic in white color so that customers may get their desired color when required. Pellets are very inexpensive compared to filaments.
Step 2: Preparation – The second step in the process is preparing the pellets and shaping them. Next they are solidified in order to form string-like structure. Now the pellets are put into an industrial blender and additives are added to it. These additives can be used to add colorants or to determine the properties such as resistance, strength etc.
Drying -Once the pellets are mixed properly they are moved to the drying section. Generally pellets absorb moisture from the air so they are called as hygroscopic. They are dried around 60°C to 80°C for a few hours.
Step 3: Shaping -The third step in this process is shaping the pellets into a string-like form. This involves both heating and cooling.
a)Heating – First the pellets are fed into a filament extruder which has a heating chamber. Here the pellets are melted into a sticky material so that the desired shape can be obtained. Now the string like material leaves the chamber and then moved into the cooling section with the help of nozzle.
b) Cooling -After leaving the chamber the filament should enter into two chambers. The first is full of warm water which is used to attain rounded filament. The second is full of warm water through which the filament cools and forms a new shape.
Step 4: Spooling -Now it is moved into the spooling section. This is done in order to check whether the filament’s diameter is as per the target diameter. Generally diameter may be 1.75 mm or 2.85 mm. Finally filament is wounded around a spool. After sensing the spool is full, the filament is detached. The same process is repeated.
Step 5:Packaging -The last step is selling the product. Company specific brand packaging is done. Packaging consists of labelling and barcodes for business purpose.