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Namograph

Grant Bradley

New Member
Hello,

Does someone have experience creating a namogram graph in excel? I have two different plastic resins with different ranges of melt index that I am trying to determine at what ratio will the melt index achieve a specific target value.

X-Axis:
Resin A = 40 to 50 MFI
Resin B = 5 to 7 MFI

Y-Axis:
Resin A = Weight %
Resin B = Weight %

Target MFI when Resin A and Resin B are combined would be 25. The result from a logarithmic sheet of paper is 70% of Resin A combined with 30% of Resin B.

The chart needs to graph or determine the intersecting MFI when the "Weight %" is varied between both "Resin" types "A" and "B" to achieve the target MFI of 25.

If anyone can help with this graph or calculation based on entering different values it would be greatly appreciated.
 
@Grant Bradley

Interesting question. I had to wikipedia namograms.

They might be easy to construct (not the weird circular ones) assuming we know the equations. I couldn't figure out equation for the MFI of combined resin from what you wrote.

That said, I think you can build a normal calculation logic where when you enter input MFIs and weights, Excel can tell you what the combined MFI would be, assuming you know the equation. You can even use either solver or goal seek to figure out weight combination that gives the desired MFI.

Please share the equation you are using on the log scale so I can help with setting up the worksheet.
 
Here is the file from the other post
 

Attachments

  • Brine_Permeability_Capillary_Pressure_Nomograph.xlsx
    397.8 KB · Views: 11
Please see the attached paper namogram chart. I put the points on the chart as explained above. I'm not sure how to create a formula for the logarithmic function but if someone can come up with a calculation that would tell me the percentages of each material to mix together based on a target value that would be good also. I used a range for MFI but the calculation could be done for a single MFI for each resin type.

It would also be beneficial to have the logarithmic chart drawn so different data sets could be applied for different types of resin.

Please let me know if there are additional questions.

Thank You
 

Attachments

  • ~OT72EWI001F.PDF
    905.1 KB · Views: 11
I don't think you need a formula, just the knowledge that there's a logarithmic relationship.
Try the following, you should be able to recognise the numbers in the equations. Format the result as % and it will show you the needed percent of the resin having the MFI of 5 v that having an MFI of 40:
=TREND({0;1},LN({5;40}),LN(25))
77.4%
Similarly for the upper values of the MFI ranges:
=TREND({0;1},LN({7;50}),LN(25))
64.75%

You can use commas instead of semicolons throughout.
 
Last edited:
Thank you for the help with the formula. I tried to create a form where I could change the values set for Resin A and B and reference these in the formula but it gives me an error. Is there a way to make that work so I can adjust the different MFI values and see what the ratios are without going into the formula to set these each time?
 
See attachment. I would like to change the melt flow values and the result to update as changes are made (link values in formula).
 

Attachments

  • Melt Flow Formula.xlsx
    8.6 KB · Views: 4
H4:
=TREND({0;1},LN(G4:G5),LN(G6))

J4:
=TREND({0;1},LN(I4:I5),LN(G6))

H5:
=1-H4

J5:
=1-J4
 
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