Blow Molding

About Blow Molding and Blow Molding Services Including: Blow Molded Cases, Blow Molded Plastics, Blow Molders, Plastic Blow Molding & Plastic Bottles.

Blow molded plastic is any hollow plastic product, the most common being bottles, which results from the blow molding process. Plastic blow molding is arguably the most common plastic molding process due to its high cost-efficiency, long run capacity and application versatility. Plastic bottles are the most commonly blow molded product, including blow molded bottles for a very wide spectrum of applications, such as clear plastic bottles, plastic water bottles, plastic baby bottles, plastic spray bottles, peanut butter jars, milk bottles, plastic cosmetic bottles, blow molded cases, garbage cans and many other containers and products. Blow molders and blow molding companies manufacture toys, CD cases and other consumer items into almost any hollow, three dimensional shape in any color and material transparency. Industrial items such as gas tanks, bulk drums and corrosive liquid containers are blow molded, as are most household chemical and cleaning containers. Plastic blow molding presents an excellent, portable containment solution for volatile substances with maximum cost efficiency.

The blow molding process begins with melting down the plastic and forming it into a parison, or preform. The parison is a tube-like piece of plastic with a hole in one end in which compressed air can pass through. Using a blow pin, air pressure is introduced through the inside of the parison, forcing it to assume the shape of the mold. The end product is cooled by conduction or the evaporation of volatile fluids in the container. The purpose of blow molding services is to form a uniform finished product that does not need to be joined together in any way. Blow molding services use three basic methods for producing blow molded plastic: extrusion, injection and stretch blow molding.

Extrusion blow molding is the simplest type that allows for a wide variety of container shapes, sizes and neck openings, along with handleware of many kinds. Injection blow molding is a hybrid of the injection molding and blow molding services and is suitable for smaller containers but not for handleware of any kind. Two types of stretch blow molding are injection stretch blow molding (ISBM) and reheat and blow (RHB) molding, both of which are typically used to manufacture P.E.T bottles for juice, water, etc. In the ISBM process, a preform is injection molded and then transferred to another station on the machine, where it is blown. Because ISBM is so costly, it requires long runs for products such as peanut butter jars, water bottles and liquor bottles. In RHB, a preform is purchased from a vendor that has already put it through an injection molding process. It is then reheated in a relatively simple machine in order to prepare it for blowing. RHB is advantageous because the purchaser does not have to invest in expensive injection molding machinery but still has access to a large catalog of existing preforms.
 
Distinct advantages exist for choosing the blow molding process over other plastic manufacturing processes. It is the most well-suited method for forming hollow plastic parts. It has much lower mold costs than injection molding. Blow molding has a faster cycle time than that of rotational molding. In many cases, one blow molded plastic piece can take the place of many individual parts. However, the scattering of mold thickness is a potential problem, and quality control is important to make sure none of the blow molded products have holes, leaks or unevenly thin walls. Strong, precisely even walls are better created by rotational molding or plastic extruding, but for the thousands of applications which require high volume production over precision, plastic blow molding is an ideal choice.

Blow Molding and Blow Molding Services Image Provided by Western Industries, Inc.

Blow Molded Plastics Types

• Blow molded cases are formed by blow molding processes.
  
• Blow molded plastics are plastic parts formed by blow molding.
  
• Blow molders create hollow plastic parts.
  
• Extrusion blow molding is the process in which a hot parison or preform is placed into a two-part mold. In the mold, the parison or preform is inflated with compressed air, which presses it against the walls, and then is cooled and removed by separating the mold halves.
  
• Injection blow molding blends the two methods of blow molding and injection molding and is typically used in the manufacturing of soda bottles. A preform, which is similar to the parison, is either injection plastic molded and then transferred to a blow molding machine, or the injection and blow molders are combined.
  
• Injection stretch blow molding (ISBM) is a two-stage, stretch blow molding process in which a preform is injection molded and then transferred to another station where it is blown and ejected from the machine.
  
• Plastic blow molding is a process that uses inflated thermoplastics in molds.
  
• Plastic bottles are hollow containers made of plastic.
  
• Reheat and blow (RHB) is a stretch blow molding process in which a preform is injection molded by a vendor and then purchased and reheated by another company.