No 
DP 
FR 
Inner diameter
of ring 
Length
of ring 
Revolution
of screw 
Temperature
of barrel heater 
Abrasion
amount 
Flowrate 
Power
consumption 
1 
A1 
B1 
C1 
D1 
data 
・・・・ 

2 
A1 
B2 
C2 
D2 



3 
A1 
B3 
C3 
D3 



4 
A2 
B1 
C2 
D3 



5 
A2 
B2 
C3 
D1 



6 
A2 
B3 
C1 
D2 



7 
A3 
B1 
C3 
D2 



8 
A3 
B2 
C1 
D3 



9 
A3 
B3 
C2 
D1 

・・・・ 
data 
5. According to the orthogonal array experiment and take data for each FR
According to the L9 orthogonal array the nine sets of experimental conditions
in rows are set and data are obtained experimentally or from calculations for each FR.
Then those data are inputted in the corresponding cells in the row positions.
In each cell a number of data exist, because experiments are done repeatedly
under the same conditions and/or under different outside conditions. When data are saved in Excel form, they can be easily imported into the software.
6 .Using the calculation software the optimum values for parameters that
satisfy all the FRs sufficiently are obtained
The recsat curve for each DP of each FR are calculated in the software
and shown on the monitor. The recsat function is explained in detail in
the book
"A Trump for Production Nakazawa Method" (sorry! it is written in Japanese).
Then a sum of the recsat curves of all the FRs for a DP, which is called "total recsat curve", is obtained
and shown. The corresponding point of the DP to the minimum total recsat
is the optimum value of the DP which satisfies all the FRs. The optimum
values of all the FRs are determined one after another. Using the software
you can easily obtain these results.
7. Making the product incorporating the above optimum values and confirm
that the FRs are satisfied , then the development ends
Once confirmed with the final product which is made from the optimum values
of DPs that all the performances are in the design ranges, the development
ends. Final results of the above injection machine is shown in Table 2.
Actually Abrasions were measured at three points.
Table 2. Final results of development

Abrasion (mm) 
Power consumption
(kWh) 
Flow rate
(productivity)
(g/min) 
Ring 
Screw head

Inner
diameter 
Length 
Length 
New type 
0.001 
0.148 
0.247 
15.3 
130 
Currently used type 
0.005 
0.234 
0.533 
32.3 
54 
This table shows that all the items are drastically improved.
When a performance or some are not obtained, please take the following
three steps.
1. When an optimum point is located at either end of the total recsat curve ( for example A1 or A3 ), experiment again reconstructing the orthogonal array of new levels of the DP which covers the expecting optimum point.
2. If that process does not succeed, another important DP may exist and
find it, and experiment again.
3. Nevertheless good results could not be obtained, the fundamental structure
( that idea ) must be thrown away to create other structures. You must
not cling to that idea to loose money and time.
How do you think this method? Isn't it easy to use? About sixty Japanese
wellknown companies introduced this method to gain much benefit.
HOME