Blow molding is a process used for manufacturing and forming hollow plastic parts. The basic steps of blow molding are also used in forming other hollow shapes such as glass bottles. Blow molding is considered a very cost-effective method of manufacturing plastics, as it used to produce large quantities of containers.
Many plastics manufacturers choose the blow molding method as it offers many distinct advantages including; ¬
- The cost of blow molding is lower than that of injection molding.
- The machinery used for blow molding also costs less than that used in injection molding.
- Blow molding is used to manufacture one-piece constructions with no need to connect part halves. This can be used to create shapes and products that couldn’t be created via injection molding.
How Blow Molding Works
With blow molding, plastic is heated and filled with air until it becomes a “parison” (a giant balloon of hot plastic). Then, a mold of the desired shape is clamped around the parison while the air continues to follow until it takes the shape of the mold.
The blow molding method allows for more liberty in the design of the mold halves since each half forms its own wall shape. There are also other factors to be monitored when using blow molding including; air leaks, streaks, wall thinning, and flash.
Wall thickness variation, for example, is considered an essential factor for product designers to consider when using blow molding. Because quality control is an essential part of the process, it is crucial to look for manufacturers and suppliers that are qualified to measure and improve every feature of the product.
Blow molding is used to manufacture many commodities including; shampoo and water bottles, jerrycans and containers, stadium chairs …. Etc.
Injection Molding
On the other hand, injection molding involves complicated engineering to create detailed molds and tools.
How Injection Molding Works
In injection molding, molds are crafted from stainless steel and aluminum then injected with liquid polymer at high temperature and at extreme pressure. Then, the molds are cooled to release the plastic parts.
Injection Molding Offers Many Advantages Such As;
- Providing highly engineered detailed tooling with multi-cavity options.
- Efficient manufacturing for large quantities of small parts.
- Flexibility in changing the colors and type of material.
- Low scrap rates.
In injection molding, the main player is the mold itself as it is the key to creating the precision part. After the production of the mold is finalized, manufacturing begins. Plastic injection molding is perfect for mass production of the same part.
After the initial run, the parts will be thoroughly checked for any defects, and when none is found full production begins. Quality checks usually take place regularly when using injection molding. Common defects, strength, and color correctness are usually checked by the manufacturer.
