Using ProMax-One Part Cost Estimator™
Step 4. Calculate cost of the molding parts
Open ProMax-One Part Cost Estimator™. Select
the Part Cost Estimator option from the main menu at injecneering.com and run the program. Retrieve the mould record as explained in step 2.
This
program calculates the cost of the parts produced by a mold. This is a comprehensive
tool that considers most variables that affect the cost to produce a molded plastic
part.
Start a new cost analysis study.
Click on the New Calculation button
Enter the materials information.
Enter values for all different parts. It is best to enter this information prior to any other information. To add a part, click on the check box below the part number
Since the specific gravity was already typed, when the part volume is entered, the weight is automatically calculated and vice versa.
Each column represents a different part. For instance for a 2+3 cavity mold, only 2 columns must exist.
Use the Other Costs fields to include any costs incurred by secondary operations such as painting, chroming, de-gating, inspection etc.
Enter the remaining data
Enter only values that will affect the part cost in accordance to your quoting policies or terms negotiated. For instance, if only a fraction of the machinery cost is to be amortized in the piece price, enter only the fractional value. If the mould is provided by the customer, the Mold Cost value should not be entered. Yet the maintenance cost may be entered.
For the runner and sprue, you only need to enter one of three values: the weight as a percentage of the total shot size, its volume or its weight. For this case study, the percentile value is used as the mould has not been designed yet.
Analyze the results. Each part cost
and a breakdown are shown in results area
A more in detail view of the values used in the calculations can be seen by clicking
on the Show Calculations Data button.
The level of detail presented in the detailed view can be controlled by checking or un-checking the check boxes that appear in the upper area of the window. To quickly
make visible one item only, right click on the corresponding check box. All other
items will be hidden.
Note: All calculations are based on the fractional weight of a part to the complete shot weight.
For example, the formula to calculate cost of labour is:
Mach Rate Per Part = Mach Rate Per Cycle * Fraction Of Total Shot
An not:
Mach Rate Per Part = Mach Rate Per Cycle / Number Of Cavities
Therefore, for this example:
Fract Of Total Shot = 31.50 g / ( 31.50 g + 27.94 g ) = 0.53
Mach Rate Part 1 = 1.389 $/Cycle * 0.53 = 0.74 $/part
And Not:
Mach Rate Part 1 = 1.389 $/Cycle / 2 Cav = 0.694 $/Part
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