First of all, we have to distinguish which kinds of plastic products are made.
Injection Molding
It is not the same as the blow molding principle, injection molding is the most widely used plastic making process. The raw material is injected into the mold with high pressure, so it is called injection molding.
Injection molding machine schematic
① Access to hydraulic pumps
② Piston for opening and closing the mold
③ Separate molds
④ Melted plastic
⑤ Screws
⑥ Hopper
⑦ Raw material particles
⑧ Finished product
⑨ Heater
⑩ Hydraulic machine piston
⑪ Fluid from hydraulic press
Like most of our caps, flip tops, swing caps, pump heads, hoods, nozzles and other such bottle accessories are all injection molding.
Screw Cap
Fine Mist Sprayer
Lotion Pump
Injection molding can be selected from almost all categories of plastic can be injection molded, the same category of plastic will have many different grades, such as PE injection molding grade, there are blow molding grade, different product applications on the choice of different grades of raw materials can be.
Many plastic products in life are also injection molded, bottle accessories are only a very small part of them, injection molding made into bottles can only be made into bottles with a larger diameter inside the mouth than inside the bottle, usually jars.
Blow Molding — Squeeze And Blow
Plastic bottle production process “blow molding” one of the raw materials are widely used PE, PP, PS, PETG EVA, etc..
The process is to melt the plastic pellets (raw materials) with a bottle blowing machine, extrude a hollow tube, cut a section into the mold, blow molding with high-pressure air, and remove the excess trim after cooling.
Extrusion blowing schematic
The color of the bottle made by extrusion is heated and extruded and blown together with the raw material and color powder mix before production.
Blow Molding — Injection, Pulling And Blowing
Plastic bottle production process “blow molding” one of them, than the simple blow molding, first more than one injection molding process, injection molding into a bottle blank and then blow molding into hollow blow molding products, bottle mouth and bottle bottom is relatively smooth without obvious burrs phi front.
PET Bottle Blanks<<
The first part is the injection of raw materials into the bottle embryo, the color of the embryo is the color of the bottle, the second part is the injection of the embryo heated into the mold through high-pressure air blow molding, materials are widely used PE, PET, PP, PC, etc. can be.
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Our commonly used PET bottles such as cosmetic bottle packaging and beverage bottles are made by injection blowing process.