What Factors Affect the Price of a Blow Molded Part?

You want to manufacture the best part possible while being kind to your budget. To understand how much your blow molding project will cost, it’s important to dig into the elements of the process that influence that bottom line.

Here are five common factors that affect the price of a blow molded part.

Resin type

The materials you use to make your product have a significant impact on cost. High- and low-density polyethylene (LDPE and HDPE) and polypropylene (PP) are the least expensive resins commonly used in blow molding.

Along with variations in pricing between materials, virgin resin pricing, which is contingent on the price of crude oil or natural gas, can fluctuate widely over time.

Part dimensions

In general, the bigger your part, the more it will cost. But there are many ways a blow molder can work with you to reduce the cost of a large part. For example, using a resin that maintains its strength even when it’s blown very thin can reduce the amount of resin you need even for a very large product. Evaluating blow conditions and properly orienting the part in both the mold and the machine can save significant cost.  With shot sizes exceeding 50 lbs., size is seldom a problem in blow molding.

Structural requirements

Compartments, corners, tabs, handles, and other structural requirements can all impact the price of your blow molding project. Each special feature of your part requires unique tooling and may influence the amount of resin required. Computerized finite element analysis (FEA) programs can help identify areas that may fail so the design and material programming can be optimized before production.

Tooling

Tooling costs are part of the capital expenditure to get your blow molding project up and running. The tooling includes the customized mold and related machinery that will produce your part precisely to your specifications. The complexity and requirements of the tooling are related to your part’s structural requirements, size, and resin type. Blow molding allows independent design on each mold half for more creativity. Molds are typically made from aluminum which has 5 times higher thermal conductivity than P-20 steel resulting in 50-70% faster cycles.  It’s also is easily machined for fast mold delivery times.  By selecting a single source for your mold and production, you can eliminate divided responsibilities and save time.

Quantities

The amount of product you are producing both in single shipment releases and in annual quantities impacts part costs. Of course it is beneficial to produce a large amount of a product to absorb the initial set-up expenditure and allow for continuous improvement.  But, nearly any quantity can be competitively quoted.  In general, 1000 pieces is the minimum recommended production run size for blow molding because it takes about 24 hours.

 

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