Sequential Injection to Multiple Mold Cavities

Abstract

An injection molding apparatus, comprising:an injection molding machine;a distribution manifold having a distribution channel,a clamp device arranged to clamp together, under a selected clamp force, a mold system having a plurality of mold cavitiesone or more first downstream channels fluidly coupled to the distribution channel;one or more first gates arranged to deliver injection fluid to a first cavity;one or more second downstream channels fluidly coupled to the distribution channel;one or more second gates arranged to deliver injection fluid to a second cavity;a control system adapted to:instruct the first upstream valve and a second upstream valve; andat least one downstream valve having a valve pin having a control surface for controlling flow of injection fluid.

What is claimed is: 
     
         1 . An injection molding apparatus, comprising:
 an injection molding machine;   a distribution manifold having a distribution channel, the distribution manifold arranged to receive injection fluid from the injection molding machine and further arranged to route injection fluid downstream via the distribution channel;   a clamp device arranged to clamp together, under a selected clamp force, a mold system having a plurality of mold cavities;   one or more first downstream channels fluidly coupled to the distribution channel;   one or more first gates, each first gate associated with a respective first downstream channel and arranged to deliver injection fluid to a first cavity of the mold system;   one or more second downstream channels fluidly coupled to the distribution channel;   one or more second gates, each second gate associated with a respective second downstream channel and arranged to deliver injection fluid to a second cavity of the mold system;   one or more downstream valves associated with each of the first and second downstream channels, the one or more downstream valves arranged to control delivery of injection fluid through the respective first and second downstream channels and associated first and second gates;   a first upstream valve arranged to enable and disable a first flow of injection fluid from the distribution channel to the one or more first gates;   a second upstream valve arranged to enable and disable a second flow of injection fluid from the distribution channel to the one or more second gates, wherein at least one of the valves has an actuator and a valve pin interconnected to the actuator, wherein the valve pin has a control surface with a selected configuration adapted to cooperate with a selected complementary surface of a respective channel, and wherein at least one rate of flow of injection fluid is controllable by controlling axial positioning of the control surface of the valve pin relative to the selected complementary surface of the respective channel; and   a control system adapted to:
 instruct the first upstream valve to enable flow of injection fluid to the one or more first gates at a first selected time; and 
 instruct the second upstream valve to enable flow of injection fluid to the one or more second gates at a second selected time that is delayed, subsequent, or sequential in time relative to the first selected time during an injection cycle. 
   
     
     
         2 . An apparatus according to  claim 1  wherein at least one of the first selected time and the second selected time is selected to provide one or both of a first peak time that is offset from a second peak time or a first pack phase time that is offset from a second pack phase time,
 wherein the first peak time is when a first peak injection fluid force or pressure occurs within the first cavity during the injection cycle, 
 wherein the second peak time is when a second peak injection fluid force or pressure occurs within the second cavity during the injection cycle, 
 wherein the first pack phase time is when a first pack phase injection fluid force or pressure occurs within the first cavity during the injection cycle, and 
 wherein the second pack phase time is when a second pack phase injection fluid force or pressure occurs within the second cavity during the injection cycle. 
 
     
     
         3 . An apparatus according to  claim 2  wherein a maximum cumulative fluid force or pressure that occurs within the first and second cavities during the injection cycle is less than a cumulation of the first and second peak injection fluid forces or pressures. 
     
     
         4 . An apparatus according to  claim 1  wherein injection fluid is injected into the first and second cavities first under a filling phase pressure or force and subsequently under a pack phase pressure or force, the filling phase pressure or force being substantially less than the pack phase pressure or force. 
     
     
         5 . An apparatus according to  claim 1  wherein the selected clamp force is at least equal to a cumulative peak force or pressure exerted by injection fluid within all of the plurality of mold cavities of the mold system over the injection cycle. 
     
     
         6 . An apparatus according to  claim 1  wherein at least one of the first selected time and the second selected time is selected to provide a time during the injection cycle at which injection fluid exerts a peak force or pressure within the first cavity that is substantially offset from a time during the injection cycle at which injection fluid exerts a peak force or pressure within the second cavity. 
     
     
         7 . An apparatus according to  claim 1  wherein at least one of the first selected time and the second selected time is selected to significantly reduce the selected force of the clamp device relative to a force equal to a combined peak force or pressure exerted by injection fluid within each of the plurality of cavities when injection fluid is delivered to the one or more first gates and the one or more second gates concurrently. 
     
     
         8 . An apparatus according to  claim 1  wherein the control system is further adapted to perform at least one additional act, the at least one additional act including:
 control timing of opening of one or more upstream valves to deliver injection fluid to at least some of the plurality of mold cavities at and over different or staggered times during the injection cycle; 
 control a degree of openness of one or more upstream valves to deliver injection fluid to at least some of the mold cavities at different selected times during the injection cycle; 
 control a degree of openness of one or more upstream valves to deliver injection fluid to at least some of the mold cavities at different selected rates during the injection cycle; 
 receive fluid pressure data from one or more pressure sensors arranged to measure fluid pressure at a selected position disposed within an upstream distribution channel; 
 control a degree of openness of one or more upstream valves during the injection cycle to deliver injection fluid to at least some of the mold cavities at different selected fluid pressures at certain selected positions to match a predetermined profile of pressures; and 
 control axial positioning of at least one valve pin to control a sequence or timing of injection fluid flow. 
 
     
     
         9 . An apparatus according to  claim 1 , further comprising:
 one or more pressure sensors interconnected to the control system and arranged to measure fluid pressure within a downstream fluid channel, the one or more pressure sensors disposed upstream and away from at least one of the first and second gates; and   a memory arranged to store a predetermined profile of fluid pressures, wherein the control system is further adapted to:
 instruct the actuator to axially position the valve pin to effect a fluid pressure at the upstream and away from a position of the at least one of the first and second gates that matches the predetermined profile of fluid pressures. 
   
     
     
         10 . An apparatus according to  claim 1 , further comprising:
 one or more pressure sensors interconnected to the control system and arranged to measure fluid pressure at one or more determined positions within a cavity; and   a memory arranged to store a predetermined profile of fluid pressures for the one or more determined positions at which the one or more pressure sensors measure pressure, wherein the control system is further adapted to:
 instruct the respective actuator of the at least one downstream valve to axially move the respective valve pin to positions that cause the pressure of fluid at the determined position within the cavity to match corresponding pressures of the predetermined profile. 
   
     
     
         11 . A method to perform an injection cycle, comprising:
 clamping a mold system together under a selected clamp force with a clamp device, the mold system having a plurality of mold cavities;   routing injection fluid via a common distribution channel to one or more first downstream channels, the one or more first downstream channels having respective associated first downstream valves and first gates that deliver injection fluid to a first cavity of the mold system;   routing injection fluid to one or more second downstream channels having respective associated second downstream valves and second gates that deliver injection fluid to a second cavity of the mold system;   enabling and disabling flow of injection fluid to the one or more associated first gates via a first upstream valve, wherein enabling flow of injection fluid to the one or more associated first gates includes instructing the first upstream valve to enable flow of injection fluid to the one or more associated first gates at a first selected time;   enabling and disabling flow of injection fluid to the one or more associated second gates via a second upstream valve wherein enabling flow of injection fluid to the one or more associated second gates includes instructing the second upstream valve to enable flow of injection fluid to the one or more associated second gates at a second selected time that is delayed, subsequent, or sequential in time relative to the first selected time during the injection cycle; and   at least one of the valves having an actuator and a valve pin interconnected to the actuator, wherein the valve pin has a control surface with a selected configuration adapted to cooperate with a selected complementary surface of the respective channel, controlling at least one rate of flow of injection fluid in the respective channel by controlling axial positioning of the control surface of the valve pin relative to the selected complementary surface of the downstream channel.   
     
     
         12 . A method according to  claim 11  wherein the selected clamp force is at least equal to a cumulative peak force or pressure exerted by injection fluid within all of the plurality of mold cavities of the mold system over the injection cycle. 
     
     
         13 . A method according to  claim 11 , further comprising:
 selecting one or both one of the first selected time and the second selected time to reduce the selected force of the clamp device relative to a force equal to a combined peak force or pressure exerted by injection fluid within each of the plurality of mold cavities when injection fluid is delivered to the one or more first gates and the one or more second gates concurrently.   
     
     
         14 . A method according to  claim 11 , further comprising:
 selecting one or both one of the first selected time and the second selected time to provide a first peak injection fluid force or pressure within the first cavity at a first peak time during the injection cycle and to provide a second peak injection fluid force or pressure within the second cavity at a second peak time during the injection cycle, wherein the first peak time is offset from the second peak time.   
     
     
         15 . A method according to  claim 12 , further comprising:
 selecting one or both one of the first selected time and the second selected time to provide a maximum cumulative fluid force or pressure within the first and second cavities during the injection cycle that is less than a cumulation of first and second peak injection fluid forces or pressures.   
     
     
         16 . A method according to  claim 11 , further comprising:
 selecting one or both one of the first selected time and the second selected time to provide a first pack phase injection fluid force or pressure within the first cavity at a first pack phase time during the injection cycle and to provide a second pack phase injection fluid force or pressure within the second cavity at a second pack phase time during the injection cycle, wherein the first pack phase time is offset from the second pack phase time.   
     
     
         17 . A method according to  claim 11  further comprising
 injecting injection fluid into the first and second cavities first under a filling phase pressure or force and subsequently under a pack phase pressure or force, the filling phase pressure or force being substantially less than the pack phase pressure or force. 
 
     
     
         18 . An injection molding system, comprising:
 a clamp device arranged to clamp a plurality of mold cavities together under a selected clamp force;   a distribution channel integrated in a distribution manifold and arranged to route injection fluid downstream;   a plurality of downstream channels fluidly coupled to the distribution channel, the plurality of downstream channels including at least one first downstream channel and at least one second downstream channel;   first and second gates associated, respectively, with each first and second downstream channel and arranged to pass injection fluid, respectively, to first and second cavities of the plurality of mold cavities;   first and second downstream valves associated with each of the first and second downstream channels, the first and second downstream valves arranged to control delivery of injection fluid through the respective first and second downstream channels and associated first and second gates;   first and second upstream valves controllably arranged, respectively, to pass first and second flows of injection fluid, respectively, from the distribution channel to each first and second gate, wherein at least one of the valves has an actuator and a valve pin interconnected to the actuator, wherein the valve pin has a control surface with a selected configuration adapted to cooperate with a selected complementary surface of a respective channel, and wherein at least one rate of flow of injection fluid is controllable by controlling axial positioning of the control surface of the valve pin relative to the selected complementary surface of the respective channel; and   a control system adapted to instruct the first upstream valve to enable the first flow of injection fluid at a first selected time and instruct the second upstream valve to enable the second flow of injection fluid at a second selected time that is delayed, subsequent, or sequential in time relative to the first selected time during an injection cycle.   
     
     
         19 . An injection molding system according to  claim 18  wherein the selected clamp force is at least equal to a cumulative peak force or pressure exerted by injection fluid within all of the plurality of mold cavities over the injection cycle. 
     
     
         20 . An injection molding system according to  claim 18  wherein at least one of the first selected time and the second selected time is selected to reduce the selected force of the clamp device relative to a force equal to a combined peak force or pressure exerted by injection fluid within each of the plurality of cavities when injection fluid is delivered to the first and second gates concurrently.