Method for measuring a flowing property in a resin transfer molding system

Patent metadata

Field	Value
Publication number	US-10946597-B2
Application number	US-201916667562-A
Country	US
Kind code	B2
Filing date	Oct 29, 2019
Priority date	May 5, 2017
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

Abstract

The present disclosure provides a measurement method for a molding system comprising an upper mold and a lower mold forming a mold cavity. The method includes applying a pressure difference to a molding resin for driving the molding resin to flow into a preform in the mold cavity; detecting a flow front of the molding resin at a first position and a second position in the mold cavity; and calculating a flowing property of the molding resin based on the first position, the second position, a travelling time of the flow front from the first position to the second position, and the pressure difference.

First claim

What is claimed is:

1. A measurement method for a molding system, the molding system comprising an upper mold and a lower mold forming a mold cavity, the method comprising:
applying a pressure difference to a molding resin for driving the molding resin to flow into a preform in the mold cavity;
detecting a flow front of the molding resin at a first position and a second position in the mold cavity by a detection device disposed over the upper mold;
detecting an internal pressure of the mold cavity by a pressure sensor disposed outside the mold cavity; and
calculating a local ratio of permeability to porosity of the preform based on the first position, the second position, a travelling time of the flow front from the first position to the second position, and the pressure difference,
wherein the mold cavity does not contain an internal pressure sensor configured to detect an internal pressure of the mold cavity.

2. The measurement method of claim 1 , wherein the step of detecting the flow front of the molding resin includes capturing a first image and a second image of the flow front at the first position and the second position respectively.

3. The measurement method of claim 2 , wherein the first image and the second image are captured by an image-capturing device as the detection device.

4. The measurement method of claim 3 , wherein the upper mold is transparent, the first image and the second image being captured through the upper mold.

5. The measurement method of claim 1 , wherein the pressure difference is constant during said travelling of the flow front from the first position to the second position.

6. The measurement method of claim 1 , further comprising measuring a front pressure of the mold cavity by a front pressure sensor coupled to an inlet port of the mold cavity, and measuring a rear pressure of the mold cavity by a rear pressure sensor coupled to an outlet port of the mold cavity.

7. The measurement method of claim 6 , wherein the steps of measuring the front pressure and the rear pressure are performed outside the mold cavity.

8. The measurement method of claim 6 , wherein the local permeability to porosity ratio of the preform between the first position and the second position is calculated based on the front pressure and the rear pressure.

9. The measurement method of claim 1 , wherein the step of calculating the local ratio of permeability to porosity includes deriving the local permeability to porosity ratio of the preform inside the mold cavity.

10. The measurement method of claim 1 , wherein the step of calculating the local ratio of permeability to porosity is performed based on the following expression:

K
~

ϕ
~

=

μ
⁢

⁢
G

P
0

⁡

(

t
n

-

t

n
-
1

)

⁢

∫

X

n
-
1

X
n

⁢

x
2

-

X

n
-
1

⁢
x

(

Gx
-
1

)

⁢
dx

where

K
~

ϕ
~

represents a local permeability to porosity ratio of the preform between the first position and the second position, μ represents a viscosity of the molding resin, P 0 represents the pressure difference, t n-1 represents a first timing at which the flow front of the molding resin is at the first position, t n represents a second timing at which the flow front of the molding resin is at the second position, X n-1 represent the first position, X n represents the second position, and x represents a travelling distance of the flow front, wherein the foresaid expression is an integral with respect to the first position and the second position of the flow front; and
where G is expressed in the following equation:

G
=

K

n
-
1

⁢
ϕ

K
⁢

⁢

ϕ

n
-
1

⁢

X

n
-
1

where

K
n

ϕ
n

is a constant, and

K

n
-
1

ϕ

Assignees

• Coretech Sys Co Ltd
• Univ Nat Tsing Hua

Inventors

• Yao Yuan
• Chiu Tzu-Heng
• Chang Rong-Yeu
• Hsu Chia-Hsiang
• Wang Chih-Wei
• Sun Shih-Po
• Huang Sung-Wei
• Yang Hsun
• Tsai Tsai-Heng

Classifications

• B29C70/546 Primary

  Measures for feeding or distributing the matrix material in the reinforcing structure · CPC title

• B29C70/54 Primary

  Component parts, details or accessories; Auxiliary operations {, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing} · CPC title

• B29C70/48 Primary

  and impregnating the reinforcements in the closed mould, e.g. resin transfer moulding [RTM] {, e.g. by vacuum} · CPC title

• G01N11/06

  by timing the outflow of a known quantity · CPC title

• B29K2995/0026

  Transparent · CPC title