Injection molding machine and viscosity measurement method

Patent metadata

Field	Value
Publication number	US-12544964-B2
Application number	US-202418759993-A
Country	US
Kind code	B2
Filing date	Jun 30, 2024
Priority date	Jul 13, 2023
Publication date	Feb 10, 2026
Grant date	Feb 10, 2026

Abstract

An injection molding machine and a viscosity measurement method of the disclosure are provided with an injection cylinder to which a viscosity measurement unit is attachable and detachable and a control device. When setting an inner diameter of the injection cylinder or an outer diameter of the injection shaft as D. For a capillary installed to the viscosity measurement unit, a capillary inner diameter is set as d. By respectively using three or more values γ k of the shear rate, k being a natural number, the control device is configured to calculate injection velocities V k based on Formula (1) and automatically sets a value of the injection velocity V k within a predetermined range, among the calculated injection velocities, as an injection velocity at a time of viscosity measurement.

[

Formula
⁢

(
1
)

]

V
k

=

d
3

8
⁢

D
2

⁢

γ
k

(
1
)

First claim

What is claimed is:

1 . An injection molding machine, comprising:
an injection cylinder, to which a viscosity measurement unit is attachable and detachable; an injection shaft, inside the injection cylinder; an injection driving device, driving the injection shaft; and a control device, controlling the injection driving device, so as to drive the injection shaft forward and rearward, wherein, when setting an inner diameter of the injection cylinder or an outer diameter of the injection shaft as D, and, for a capillary die and/or a slit die installed to the viscosity measurement unit, a capillary inner diameter is set as d and a slit length and a slit width are respectively set as B and H, the control device is configured to, by respectively using three or more values γ k of shear rate, k being a natural number, calculate injection velocities V k based on Formula (1) or (2) below and automatically set a value of the injection velocity V k within a predetermined range, among the calculated injection velocities, as an injection velocity at a time of viscosity measurement

[

Formula
⁢

(
1
)

]

V
k

=

d
3

8
⁢

D
2

⁢

γ
k

(
1
)

[

Formula
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(
2
)

]

V
k

=

2
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BH
2

3
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π
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D
2

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γ
k

.

(
2
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2 . The injection molding machine as claimed in claim 1 , wherein the viscosity measurement unit comprises:
the capillary die and/or the slit die; a measurement cylinder, to which the capillary die and/or the slit die is installed; and a pressure sensor, measuring a pressure of a molding material flowing in the measurement cylinder.

3 . The injection molding machine as claimed in claim 2 , wherein the viscosity measurement unit is configured so that two or more dies of different specifications are able to be installed to the viscosity measurement unit.

4 . The injection molding machine as claimed in claim 2 , wherein, the control device is configured to, for each value of the injection velocity V k within the predetermined range, calculate a viscosity η k of the molding material in accordance with the value of the injection velocity V k by using a measurement value obtained from the pressure sensor by operating the injection driving device.

5 . The injection molding machine as claimed in claim 4 , further comprising a display device, wherein the control device is configured to display the value of the injection velocity V k within the predetermined range and a value of the viscosity η k on the display device.

6 . The injection molding machine as claimed in claim 5 , wherein the viscosity measurement unit comprises a temperature sensor measuring a temperature of the molding material flowing in the measurement cylinder,
the control device, for each value of the injection velocity V k in the predetermined range, obtains an actual measurement value T k of the temperature of the molding material obtained from the temperature sensor by operating the injection driving device, and the control device further displays the actual measurement value T k of the temperature of the molding material on the display device.

7 . The injection molding machine as claimed in claim 5 , wherein the control device is configured to draw and display, on the display device, a graph illustrating a relationship between a value γ k of the shear rate and the value of the viscosity η k .

8 . The injection molding machine as claimed in claim 7 , wherein the viscosity measurement unit comprises a temperature sensor measuring a temperature of the molding material flowing in the measurement cylinder,
the control device, for each value of the injection velocity V k in the predetermined range, obtains an actual measurement value T k of the temperature of the molding material obtained from the temperature sensor by operating the injection driving device, and the control device further displays the actual measurement value T k of the temperature of the molding material on the display device.

9 . The injection molding machine as claimed in claim 5 , wherein the control device is configured to draw and display, on the display device, a graph illustrating a relationship between a value obtained by correcting the value γ k of the shear rate with Rabinovich correction and a value obtained by correcting the viscosity η k with Rabinovich correction.

10 . The injection molding machine as claimed in claim 5 , wherein the three of more values γ k of of the shear rate are values selected within a range of 1*101 sec-1 or more and 5*105 sec-1 or less, where * represents multiplication, and
the predetermined range of the injection velocity is 0.05 mm·sec −1 or more and 200 mm·sec −1 or less.

11 . The injection molding machine as claimed in claim 10 , wherein the three or more values γ k of of the shear rate are five values, which are R*10 1 sec −1 , R*10 2 sec −1 , R*10 3 sec −1 , R*10 4 sec −1 , and R*10 5 sec −1 , R being a number of 1 or more and 5 or less.

Assignees

• Sodick Co Ltd

Inventors

• Aiba Shuji

Classifications

• B29C45/77

  of velocity or pressure of moulding material · CPC title

• B29C2945/76006

  Pressure · CPC title

• B29C2945/7604

  Temperature · CPC title

• B29C2945/76204

  injection piston cylinder · CPC title

• B29C2945/7605

  Viscosity · CPC title