Method for controlling a rate or force of a clamp in a molding system using one or more strain gauges
A method of monitoring and controlling a molding clamping apparatus in an injection molding or other molding process is disclosed. The method includes creating a target strain profile, receiving a deviation limit, receiving a change in strain relating to a mold while it is closing from a first strain gauge, identifying a deviation from a target strain profile based on the output from the first strain gauge, determining that the deviation exceeds the deviation limit, and adjusting the rate or force of clamp movement. The target strain profile may have a first portion relating to a clamp closing process, a second portion relating to a filling process, and a third portion relating to a clamp opening process. The first portion relating to the clamp closing process may include an intermediate portion relating to a coining process having an intermediate clamp force setpoint.
1. A method of monitoring and controlling a molding clamping apparatus comprising:
creating, by one or more processors, a target strain profile for a clamping and unclamping process of a molding apparatus;
receiving, via an interface, an upper deviation limit and a lower deviation limit for the target strain profile;
measuring and amplifying a change in strain experienced by a first mold side with a first portion of a strain gauge assembly, the first portion of the strain gauge assembly being secured to the first mold side and a second portion of the strain gauge assembly being secured to a second mold side, wherein the first portion of the strain gauge assembly is acted upon by the second portion of the strain gauge assembly when the first mold side and the second mold side are closed;
receiving, as an output from the first portion of the strain gauge assembly, the amplified change in strain;
receiving, as an output from a temperature sensor, temperature data taken from the first mold side on which the first portion of the strain gauge assembly is located;
identifying, by the one or more processors, a deviation from the target strain profile based on the amplified change in strain provided as the output from the first portion of the strain gauge assembly and the temperature data provided as the output from the temperature sensor;
comparing, by the one or more processors, the deviation to the upper deviation limit or the lower deviation limit;
determining, by the one or more processors, that the deviation exceeds the upper deviation limit or is less than the lower deviation limit and adjusting a rate or a force of clamp movement.
2. The method of monitoring and controlling a molding clamping apparatus of claim 1 , wherein the first portion of the strain gauge assembly is configured to be portable between multiple locations on the outside surface of the molding apparatus or to a second molding apparatus or to a strain gauge bracket.
3. The method of monitoring and controlling a molding clamping apparatus of claim 1 , and:
receiving, as an output from a supplemental strain gauge, a supplemental change in strain; and
identifying, by the one or more processors, the deviation from the target strain profile based on the amplified change in strain provided as the output from the first portion of the strain gauge assembly and the supplemental sensed change in strain provided as the output from the supplemental strain gauge.
4. The method of monitoring and controlling a molding clamping apparatus of claim 1 , wherein adjusting the rate or the force of clamp movement includes adjusting a flow of oil to at least one hydraulic valve.
5. The method of monitoring and controlling a molding clamping apparatus of claim 1 , wherein adjusting the rate or the force of clamp movement includes adjusting an electric current or voltage to an electric motor.
6. The method of monitoring and controlling a molding clamping apparatus of claim 1 , wherein the target strain profile has a first portion relating to a clamp closing process, a second portion relating to a filling process, and a third portion relating to a clamp opening process.
7. The method of monitoring and controlling a molding clamping apparatus of claim 6 , wherein the first portion relating to the clamp closing process includes an intermediate portion relating to a coining process having an intermediate clamp force setpoint.