Have you ever went to purchase an item and questioned how the company came up with the cost? A frequently asked question with injection molding is what determines the price. Six properties influence the rates. These properties include the raw materials being used, molding and labor, shipping and storage, maintenance and inspection, tooling, and packaging. The pie chart shown above illustrates a general breakdown of these properties (Bryce, 208).

Show Us What You’re Made Of

Raw materials make up forty percent of injection molding costs. A few different factors affect the cost of raw materials. These factors include questioning if regrind can be used, how much can be used, and how much regrind does the cycle produce on its own. Regrind is a byproduct of the manufacturing process. It is the recycled plastics that have already been processed through an injection molding cycle and its been ground or chopped up. If regrind is being used, the ideal amount is fifteen percent. Ultimately the volume needed to mold the parts is compared against the volume needed to fill the runner system. Each company has set equations that they use to come up with these values which provide the production cost for the molds.

Molding the Labor

Making up twenty percent of the cost is molding and labor fees. The cost for labor is generally incorporated in the injection molding machine rate. However, there are times when labor costs aren’t integrated. Determining the hourly rate and factoring in all costs that aren’t directly related to labor can be carefully calculated. A general rule of thumb is that if the labor increases, so does the cost. Each company has its own variables that are factored in to calculate the pricing. Non-related costs can include overhead values, indirect production costs, and benefits. These extra considerations generally double the hourly rate. For molding, the cycle time needs to be determined. Cycle time is the amount of time it takes from injection to ejection of the molded product. In order to calculate this, the wall thickness has to be identified and then plugged into a specific equation that’s unique to each company. This formula will calculate the molding cost of each unit.

From Point A to Wherever It Needs to Be

Shipping and storage rates encompass the smallest portion of costs. They only take up six percent of the total injection molding cost. Shipping costs fluctuate based on a variety of factors. One of the major factors that influences shipping rates is whether the product is being manufactured on shore or offshore. With manufacturing overseas, air freight will be the best option but this can get pricey although it reduces delivery time. The larger the mold is, the more expensive the freight will be since costs are based around the package dimensions and weight. Another factor with shipping overseas that needs to be accounted for is that the packages will have to go through customs. Manufacturing in the states will generally lower the shipping rates although the factories geographical location can influence the rates. One thing the project team often forgets to consider is where the products will be stored once they’ve been manufactured. Just in time (JIT) is a concept that’s structured around this problem. JIT implements that once parts are manufactured they are used immediately. This helps reduce storage fees although it’s very difficult to achieve this concept. If this concept can’t be met, there should already be a plan set in place which was determined during phase one of project development. The storage area should keep in mind temperature control, renting and storage fees, and also its location.

Sustaining Standards

Fourteen percent of costs are correlated to maintenance and inspection. This is for both the mold and the machines. As with most technologies and machines, the overall goal is to keep the mold running in top condition. These costs factor in the upkeep of the mold, which equals to eight percent of the original tooling cost. These costs cover machine parts, lubricant, damage repair, and any other maintenance that has to be taken care of. The products being produced should also be inspected. After each trial, there is an inspection phase. There are a numerous amount of factors to inspect with plastics. Some common elements that show up are sink marks, flash, bubbles, and weld lines.

The Right Tools For the Job

Tooling makes up twelve percent of injection molding costs. These costs have some flexibility since there are a variety of designs and types of steels used for the mold itself. Molds can be made out steel, aluminum, beryllium copper, and various other metals. The type of metal used for the mold, the number of mold cavities, and the size of the mold are all main factors in determining the tooling costs. The type of plastic being used in the molds also affects the tooling. If the plastic is using reinforcements or fillers, it can wear down the machine faster. For example, if glass fillers are being used, its more abrasive which will cause machine deterioration over a period of time.

Making Sure the Product Ships Safely

Last but not least, packaging is included in the cost breakdown. Packaging composes eight percent of costs. Here at Jaycon Systems, we do box-builds, custom shaped packaging, and thermoforming. Packing costs are determined by a few factors.

  •     The size of the container being used
  •     How the product is going to be placed
  •     The amount of space it takes up
  •     The number of products per container
  •     The materials used in order to execute the activity

 

All of these factors should influence the hourly wage by one and a half or three times the standard amount. This is a general rate to follow although every company is different in how they determine pricing. There is no set calculation to determine exact packaging prices.

Customized For Our Customers

There are a lot of different elements that come together to generate the cost of an injection mold. Some are obvious factors, and others aren’t as thought about as they should be. Each quote for injection molding is customized to fit the customer’s needs, and has built in room for revisions. The goal for every customer is different, which makes no two quotes the same. Next time a quote is provided for an injection mold, consider all of the factors that go into the end result.

 


Sources:

Bryce, Douglas M. Plastic Injection Molding...material selection and product design fundamentals. Volume 2: Fundamentals of Injection Molding series. Michigan: Society of manufacturing Engineers, 1997. Print.


"Tooling and Molds for Plastic Injection Molding - Rebling Plastics." Rebling Plastics. N.p., n.d. Web. 29 Apr. 2016.