Optimising a Formulation
When looking at a production formulation it is impossible to understand the nature of the cost centres in the formulation and therefore how to cost optimize that formulation.
In the CompuChem formulation optimizer the formulation is presented in such a way that it is easy to manipulate the formulation for cost optimization
The optimization process in CompuChem begins with importing a production formulation into the Paint Laboratory database using the menu option shown below
Once the formulation is imported into the paint laboratory database the optimization process can begin
When the formulation has been imported it is initially in the same format as the production formulation but excluding the manufacturing instructions the vital statistics of the formulation are displayed at the bottom of the screen
The first stage of optimization is to sort and consolidate the raw materials so that recurring raw materials are brought together under the same code and the materials are sorted in the order of pigment filler binder solvent and miscellaneous
formulation before optimization
To start optimization select the following menu options to sort and then consolidate raw materials
Formulation after sort and consolidate
At this stage no constraints have been set on the formulation.
if we look at the bottom of the screen we can see the calculated vital statistics of the formulation
Now we have covered the basics of working with the optimizer let's look at a typical example of recalculating the formulation
Notes that whatever constraints we set on the formulation the formulation will always be optimized using the objective function ‘minimize cost’
Let's say for example we wish to increase the volume non volatile of this formulation while keeping the hiding power constant and staying below the critical PVC
Note that the calculated PVC is well below the critical PVC in this particular formulation
By clicking on the maximum PVC box and the minimum volume non volatile box the existing values will automatically be inserted into these boxes
Say for instance we wish to increase the volume non volatile to 50% while keeping the PVC below the critical PVC value at say 40%
We simply change these values in the corresponding boxes
We now set constraints in the formulation in order to retain the properties of the coating
Let's set the mass per liter of the pigments as a constraint, the ratio of the binders as a constraint, the ratio of the solvents as a constraint and the mass percent of the miscellaneous items as a constraint (using the appropriate menu options from the top menu)
The formulation will instantly be re calculated using the objective function minimize cost
Notice that's the cost of the new formulation is instantly calculated
we can experiment with how the cost will vary changing volume non volatile's and PVC simply by clicking the up and down arrows in the appropriate box or or entering new values
Notice for instance how increasing the PVC closer to the critical PVC value reduces the cost
Careful consideration of the constraints on the raw materials is essential in order to optimize the formulation without changing the physical properties of the final coating.