US2021213663A1PendingUtilityA1
Method for deriving bulk viscosity of molding material
Est. expiryJan 13, 2040(~13.5 yrs left)· nominal 20-yr term from priority
B29C 2945/76053B29C 45/0046G01N 11/00B29C 45/7693B29C 2945/76859G01N 25/16B29C 2945/76107B29C 2945/76287B29C 45/77G06F 30/28B29C 2945/76006G06F 2113/22B29C 45/7646B29C 2945/7604B29C 45/766B29C 2945/76434
69
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Claims
Abstract
The present disclosure provides a method for deriving a bulk viscosity of a molding material. The method includes a step of deriving a plurality of parameters in relation to pressures, specific volumes and temperatures (PVT) of the molding material under a plurality of cooling rates and a plurality of mechanical pressures; deriving an equilibrium pressure based on the plurality of parameters obtained from a first slowest cooling rate among the plurality of cooling rates; deriving a rate of volume change of the molding material; and obtaining the bulk viscosity of the molding material based on the rate of volume change.
Claims
exact text as granted — not AI-modified1 . A method for deriving a bulk viscosity of a molding material, comprising:
measuring pressures, specific volumes and temperatures (PVT) of the molding material under a plurality of cooling rates and a plurality of mechanical pressures performed by a measuring apparatus, wherein the measuring apparatus includes a testing chamber configured for holding the molding material therein, a temperature-controlling cylinder configured for forming the testing chamber and a piston configured for sealing an opening of the temperature-controlling cylinder, and wherein the measurement includes applying the plurality of cooling rates to the molding material inside the testing chamber under an isobaric environment, or applying the plurality of mechanical pressures to the molding material inside the testing chamber under an isothermal environment; deriving a plurality of parameters in relation to the pressures, specific volumes and temperatures (PVT) of the molding material based on the measurement; deriving an equilibrium pressure based on the plurality of parameters obtained from a first slowest cooling rate among the plurality of cooling rates; deriving a rate of volume change of the molding material; obtaining the bulk viscosity of the molding material based on the rate of volume change; simulating the molding material based on the bulk viscosity of the molding material to derive a simulation result of the molding material; and transmitting the simulation result of the molding material to a controller to control a molding machine based on the bulk viscosity of the molding material to perform a molding process.
2 . (canceled)
3 . The method of claim 1 , wherein the plurality of cooling rates and the plurality of mechanical pressures are provided respectively by changing a temperature in the testing chamber and changing a pressure in the testing chamber of the measuring apparatus by the piston.
4 . The method of claim 1 , wherein the equilibrium pressure is derived by the following expression:
{circumflex over (ν)}(σ, T,Q ) PVTQ ={circumflex over (ν)}( p,T ) equilibrium PVT
where {circumflex over (ν)} is a specific volume, a is a mechanical pressure, T is a temperature, Q is a cooling rate, p is the equilibrium pressure.
5 . The method of claim 1 , wherein the deriving of the plurality of parameters includes:
deriving a plurality of control factors in relation to a pressure effecting on the molding material based on the first slowest cooling rate obtained from the plurality of parameters of the molding material; deriving a plurality of control factors in relation to a cooling rate effecting on the molding material.
6 . The method of claim 5 , wherein the plurality of control factors in relation to the pressure are represented by the following expressions:
(
T
t
)
slow
=
a
T
t
P
+
b
T
t
(
α
m
)
slow
=
α
m
1
+
(
α
m
0
-
α
m
1
)
(
1
+
(
λ
m
P
)
2
)
n
m
-
1
2
(
α
s
)
slow
=
α
s
1
+
(
α
s
0
-
α
s
1
)
(
1
+
(
λ
s
P
)
2
)
n
s
-
1
2
(
v
^
t
)
slow
=
a
v
^
t
P
+
b
v
^
t
where (T t ) slow is a transition temperature under the first slowest cooling rate, (a Tt , b Tt ) are control factors in relation to the pressure under the transition temperature and the first slowest cooling rate, (α m ) slow is a volumetric coefficient of thermal expansion of the molding material in a molten state under the first slowest cooling rate, (α m0 , α m1 , λ m , n m ) are control factors in relation to the pressure effecting on the volumetric coefficient of thermal expansion in the molten state under the first slowest cooling rate, (α s ) slow is the volumetric coefficient of thermal expansion of the molding material in a solid state under the first slowest cooling rate, (α s0 , α s1 , λ s , n s ) are control factors in relation to the pressure effecting on the volumetric coefficient of thermal expansion in the solid state under the first slowest cooling rate, ({circumflex over (ν)} t ) slow , is a specific volume at the transition temperature under the first slowest cooling rate, (a {circumflex over (ν)}t , b {circumflex over (ν)}t ) are control factors in relation to the pressure effecting on the specific volume at transition temperature under the first slowest cooling rate.
7 . The method of claim 5 , wherein the plurality of control factors in relation to the cooling rate are represented by the following expressions:
T t =q T t (ln( Q )−ln( Q slow ))+( T t ) slow
α m =q α m (ln( Q )−ln( Q slow ))+(α m ) slow
α s =q α s (ln( Q )−ln( Q slow ))+(α s ) slow
{circumflex over (ν)} t =({circumflex over (ν)} t ) slow exp(∫ T t T m (α m ) slow dT−∫ T t T m α m dT )
where q Tt is the control factor in relation to the cooling rate at a transition temperature, q αm is the control factor in relation to the cooling rate effecting on a volumetric coefficient of thermal expansion in a molten state of the molding material, q αs is the control factor in relation to the cooling rate effecting on the volumetric coefficient of thermal expansion in a solid state of the molding material, Q slow is the first slowest cooling rate, T m is an extreme high temperature that cooling rate effect can be neglected.
8 . The method of claim 5 , further comprising:
selecting a second slowest cooling rate based on the first slowest cooling rate.
9 . The method of claim 8 , wherein the second slowest cooling rate is represented by the following expression:
N*Q slow where N is a number substantially smaller than 1.
10 . The method of claim 9 , wherein the number is equal to 0.1.
11 . The method of claim 1 , wherein the bulk viscosity is obtained based on the following expression:
-
μ
d
=
σ
-
p
∇
·
u
where σ is a mechanical pressure on the molding material, p is a calculated equilibrium pressure, and ∇·u is the rate of volume change.
12 . The method of claim 1 , wherein the deriving of the plurality of parameters includes deriving a volumetric coefficient of thermal expansion of the molding material in a solid state and a volumetric coefficient of thermal expansion of the molding material in a molten state.
13 . The method of claim 1 , wherein the specific volume of the molding material is represented by the following expression:
{circumflex over (ν)}={circumflex over (ν)} t exp(∫ T t T α ν ( T ) dT )
where {circumflex over (ν)} t is the specific volume of the molding material at a transition temperature, T is a temperature, T t is the transition temperature of the molding material, α v is a volumetric coefficient of thermal expansion of the molding material.
14 . The method of claim 13 , wherein the volumetric coefficient of thermal expansion of the molding material is represented by the following expression:
α
v
(
T
,
P
,
Q
)
=
{
α
m
,
if
T
>
T
t
+
Δ
T
α
s
+
α
m
-
α
s
2
Δ
T
(
T
-
(
T
,
-
Δ
T
)
)
,
if
T
t
-
Δ
T
<
T
<
T
t
+
Δ
T
α
s
,
if
T
<
T
t
-
Δ
T
where α v is the volumetric coefficient of thermal expansion, T is a temperature, P is a pressure, Q is a cooling rate, α m is the volumetric coefficient of thermal expansion in the molten state, α s is the volumetric coefficient of thermal expansion in the solid state, T t is the transition temperature, and ΔT is a control factor of the transition state.
15 . (canceled)
16 . A molding system for preparing an article, comprising:
a molding machine; a mold disposed on the molding machine and having a mold cavity for being filled with a molding material; a processing module configured to generate a molding condition for the molding machine based in part on a bulk viscosity effect of the molding material within the mold cavity; and a controller operably communicating with the processing module and configured to control the molding machine based on the molding condition obtained from the processing module to perform an actual molding process for preparing the article, wherein the bulk viscosity effect is obtained based on the following expression:
-
μ
d
=
σ
-
p
∇
·
u
where σ is a mechanical pressure on the molding material, p is a calculated equilibrium pressure, and ∇·u is a calculated rate of volume change.
17 . The molding system of claim 16 , wherein a plurality of parameters in relation to physical properties of the molding material are measured by a measuring apparatus prior to the actual molding process.
18 . The molding system of claim 17 , wherein the plurality of parameters are inputted to the processing module.Cited by (0)
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