Mold Part Costs Are Introduced

• Posted by Jin hong February 5, 2021 - Filed in Arts & Culture - #Guide bush Mold parts  - 833 views

  Material Choice and Part Weight,
  The plastic material selection you make for your plastic part is not only critical to the part’s function, it also plays a huge role its cost to manufacture. Raw plastic material cost can range in price from $1 per pound to $25 per pound. So, care should be taken in plastic part design to minimize the weight of the part when possible.

  Choosing the correct plastic type can also help achieve faster cycle times or production rates of your parts to reduce overall costs. For small parts the cost of the material has a small effect on the unit price and the production rate has a large effect. On larger heavier parts the cost of the material has a large effect on the unit price along with the production rate.

  $ Material Part Cost = $ Plastic Material Price x Part Weight lbs

  Cycle Time and Mold Cavities
  “Cycle time” is a term used in our industry for both injection molding and CNC machining. In simple terms it is the amount of time required for a machine to complete one production cycle. The total injection molding cycle time is made up of the following steps:

  mold closing time
  injection fill time
  injection pack/hold time
  cooling time
  mold opening time
  part ejection or take out time
  re-cycle time (which would only apply when parts must be ran in a semi-automatic mode with a machine operator)
  So how does cycle time relate to part cost? Let’s discuss the primary sources of the non-material related costs for injection molding.

  Non-Material Related Costs
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  Let’s start with the machinery and equipment. Today’s high-tech servo driven injection Mold parts machinery is very expensive. The tonnage size rating of the machine and its surrounding support equipment will determine the overall capital investment required to run production. Small tonnage machine sizes are used for running small molds and small parts, and large tonnage machines are needed to run large molds with large parts.

  Even a small injection molding machine along with its support equipment will cost near $100,000 and very large machines will cost millions of dollars. It also follows that the machinery has a finite effective life cycle because it wears out and also loses its technological advantage to newer technology over time, just like everything these days. Knowing the cost being the capital ($) investment in machinery divided by its effective life cycle (time), it’s easy to understand that translates into an hourly operational cost of ownership of the equipment.

  Secondary to the capital equipment costs discussed above, would be a combination of fixed and variable costs like a factor for rent on manufacturing space, electrical power usage, etc. Through simple math these costs are also very easy to drill down into an hourly operational cost.

  The sum of all non-material related hourly costs combined and calculated out with a profit margin will become what is known as “machine rate” in our industry.

  Finally, here is how the simple non-material related cost of an injection molded part is determined by cycle time:

  The # of units produced per hour = (3600 sec / cycle time sec) x number of mold cavities

  $ Non-Material Part Cost = $ Machine Rate per hour / # of units produced per hour

  Since machine rates are all very competitive across the injection molding industry, cycle time and number of cavities in the mold are two significant determining factors in the total cost of a plastic molded part.

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