US 6,006,601 A · Method for determining the precise initial volume of a mold cavity of an injection molding machine

Abstract

A process for determining the precise initial volume of the mold cavity of an injection molding machine in which a first and second section engage into seated alignment thereby forming a mold cavity. Vent valves, controlling communication between the interior and exterior of the mold cavity, are closed thereby sealing the mold cavity. An injection means begins injecting a test substance into the mold cavity. The test substance continues filling the mold cavity until the detection of a predetermined threshold level. A measuring means performs the step of measuring the amount of the test substance in the mold cavity, thereby providing sufficient information for calculating the precise initial volume of the mold cavity of the injection molding machine. The apparatus used to perform the method described herein comprises an injection molding machine with a mold cavity configured with vent valves capable of sealing the interior of the mold cavity from the exterior. A processing unit operatively connects to the injection molding machine, and a computer-readable control program code executing on the processing unit works the methods described herein to which the present invention relates.

Claims44

Dependent claims

A method for determining a precise initial volume of plastic necessary to fill a mold cavity of an injection molding machine, said method comprising the steps of:

a) providing a first mold section;
b) providing a second mold section capable of seated alignment with said first mold section thereby forming a mold cavity;
c) providing a vent valve capable of open and closed communication with said mold cavity;
d) providing an injection means;
e) providing a measuring means;
f) forming a mold cavity by moving said second mold section into seated alignment with said first mold section;
g) sealing said mold cavity by closing said vent valve;
h) injecting a test substance of a known density and compressibility through said injection means;
i) filling said mold cavity with said injected test substance until said measuring means detects a predetermined threshold level;
j) measuring the amount of said test substance injected into said mold cavity with said measuring means;
and
k) calculating said precise initial volume of plastic necessary to fill said mold cavity based on information from said measuring means.

9 more elements

A method for determining a precise initial volume of plastic necessary to fill a mold cavity of an injection molding machine, said method comprising the steps of:

a) providing a first mold section;
b) providing a second mold section capable of seated alignment with said first mold section thereby forming a mold cavity;
c) providing a vent valve capable of open and closed communication with said mold cavity;
d) providing an injection means for injecting a gas of known density and compressibility into said mold cavity;
e) providing a measuring means said measuring means comprising:
I) a flow meter for measuring the mass of said gas in said mold cavity;
ii) a pressure transducer for measuring the pressure of said test substance in said mold cavity;
iii) a pressure transducer for detecting a predetermined threshold level of said gas in said mold cavity;
and
iv) a thermocoupler for measuring the temperature of said gas in said mold cavity;
f) forming said mold cavity by moving said second mold section into seated alignment with said first mold section;
g) sealing said mold cavity by closing said vent valve;
h) injecting said gas into said mold cavity through said injection means;
i) filling said mold cavity with said gas until said measuring means detects said predetermined threshold level;
j) stabilizing said gas in said mold cavity by waiting a predetermined period of time after the detection of said predetermined threshold level to ensure that said predetermined threshold level remains substantially the same;
k) measuring the amount of said gas injected into said mold cavity with said measuring means said measuring comprising the steps of
i) measuring said mass of said test substance in said mold cavity with said flow meter;
ii) measuring said pressure of said test substance in said mold cavity with said pressure transducer;
iii) detecting said predetermined threshold level of said test substance in said mold cavity with said pressure transducer;
and
iv) measuring said temperature of said test substance in said mold cavity with said thermocoupler;
l) calculating said precise initial volume of plastic necessary to fill said mold cavity based on information from said measuring means.

19 more elements

A method for determining a precise initial volume of plastic necessary to fill a mold cavity of an injection molding machine, said method comprising the steps of:

a) providing a first mold section;
b) providing a second mold section capable of seated alignment with said first mold section thereby forming a mold cavity;
c) providing a vent valve capable of open and closed communication with said mold cavity;
d) providing an injection means comprising:
i) an injection nozzle comprising an inline injector assembly for injecting air into said mold cavity;
ii) a gate valve means for communication between said injection nozzle and said mold cavity comprising:
a) a mold cavity inlet for operative contact with said injection nozzle;
b) a mold cavity gate for operative contact with said mold cavity inlet;
and
c) a gate valve enabling open and closed communication between said mold cavity gate and said mold cavity;
iii) a pump means for pumping said air into said injection nozzle comprising:
a) a reservoir for drawing said air from;
and
b) a rotary pump for pressuring said air;
e) providing a measuring means comprising:
i) a flow meter for measuring the mass of said air in said mold cavity;
ii) a pressure transducer for measuring the pressure of said air in said mold cavity;
iii) a pressure transducer for detecting said predetermined threshold level of said air in said mold cavity;
and
iv) a thermocoupler for measuring the temperature of said air in said mold cavity;
f) providing a computer means comprising:
i) a processing unit operatively connected to said second mold section, said vent valve, said injection means, and said measuring means;
and
ii) providing a computer program executable on said processing unit, wherein said processing unit performs said method for determining said precise initial volume of plastic necessary to fill said mold cavity of said injection molding machine;
g) forming said mold cavity by moving said second mold section into seated alignment with said first mold section;
h) sealing said mold cavity by closing said vent valve;
i) injecting said air into said mold cavity said injecting comprising the steps of:
i) engaging said inline injection assembly with said mold cavity inlet;
ii) drawing said air from said reservoir with said rotary pump;
iii) pressurizing said air in said rotary pump;
iv) pumping said air into said injection nozzle with said pump means;
and
v) injecting said air into said mold cavity through said inline, injector assembly;
j) filling said mold cavity with said air until said measuring means detects said predetermined threshold level;
k) stabilizing said air in said mold cavity by waiting a predetermined period of time after the detection of said predetermined threshold level to ensure that said predetermined threshold level remains substantially the same;
l) measuring the amount of said air injected into said mold cavity with said measuring means said measuring comprising the steps of:
i) measuring said mass of said air in said mold cavity with said flow meter;
ii) measuring said pressure of said air in said mold cavity with said pressure transducer;
iii) detecting said predetermined threshold level of said air in said mold cavity with said pressure transducer;
and
iv) measuring said temperature of said air in said mold cavity with said thermocoupler;
m) removing said air from said mold cavity by opening said vent valve;
n) calculating said precise initial volume of plastic necessary to fill said mold cavity based on information from said measuring means said calculating comprising the step of:
i) utilizing the equation V=RMT/P where V equals said precise initial volume of said mold cavity, T equals the temperature of said air in said mold cavity, P equals the pressure of said air in said mold cavity, M equals the mass of said air in said mold cavity in moles, and R equals a constant associated with said air.

41 more elements

Dependencies are inferred from the claim text.

Method for determining the precise initial volume of a mold cavity of an injection molding machine

Life of this patent

Method for determining the precise initial volume of a mold cavity of an injection molding machine

Life of this patent

Abstract

Claims44