Energy efficient blow molder control
Blow molder system and associated method optimizes the performance, energy efficiency and/or operating costs of the blow molder. A blow molder controller executes a system model that relates blow molder input parameter changes to the characteristics of containers generated by the blow molder. Equipped with energy and/or operating cost data for operating the blow molder, the blow molder controller can select a set of blow molder input parameter changes for the blow molder that: drives the containers produced by the blow molder toward desired container characteristics, in an efficient amount of time, and in cost effective manner, considering the energy costs involved in implementing the changes.
1. A blow molder system comprising:
a blow molder for performing a blow molding process, wherein the blow molder comprises:
a plurality of molds; and
a blow molder sensor for sensing an operating condition of the blow molder;
an inspection system for inspecting plastic objects involved in the blow molding process; and
a blow molder controller that is in communication with the blow molder and the inspection system, wherein the blow molder controller is configured to:
receive outputs from the blow molder sensor and the inspection system;
determine a set of blow molder input parameters for the blow molder that drives the blow molding process toward a desired characteristic, wherein the set of blow molder input parameters are determined based on:
the outputs from the inspection system and blow molder sensor; and
operating cost data, wherein the operating cost data comprises energy costs for operating the blow molder; and
output the set of blow molder input parameters to the blow molder for implementation by the blow molder,
wherein the blow molder controller determines the set of blow molder input parameters by determining the set of blow molder input parameters that optimize a plurality of factors, wherein the plurality of factors comprise:
satisfaction of the desired characteristic; and
operating costs to implement the set of blow molder input parameters.
2. The blow molder system of claim 1 , wherein:
the blow molder produces plastic containers from plastic preforms; and
the desired characteristic comprises a desired characteristic of the containers produced by the blow molder.
3. The blow molder system of claim 2 , wherein the plastic objects comprise the plastic containers produced by the blow molder.
4. The blow molder system of claim 2 , wherein the plurality of factors further comprise an expected scrap rate for containers produced by the blow molder until the containers reach the desired container characteristic.
5. The blow molder system of claim 4 , wherein the set of blow molder input parameters comprises a change to at least one of the following operating parameters of the blow molder:
pre-blow timing;
pre-blow pressure;
power levels for individual heater elements of the plurality of molds;
preform temperature set points;
stretch rod timing; and
blow pressure.
6. The blow molder system of claim 5 , wherein the energy costs comprise electricity costs for a plant where the blow molder is located.
7. The blow molder system of claim 2 , wherein the blow molder controller determines the set of blow molder input parameters by performing steps that comprise:
determining multiple sets of blow molder input parameters, wherein each of the multiple sets of blow molder input parameters drives the containers generated by the blow molder toward the desired container characteristic; and
determining an incremental cost associated with each of the multiple sets of blow molder input parameters, wherein the incremental costs are determined based on current operating parameters of the blow molder and the energy costs for the blow molder, wherein the current operating parameters of the blow molder are sensed, at least in part, by the blow molder sensor; and
selecting a first set of blow molder input parameters from the multiple sets of blow molder input parameters based on the incremental costs associated with each of the multiple sets of blow molder input parameters.
8. The blow molder system of claim 2 , wherein the blow molder blows a fluid into the preforms to form the containers.
9. The blow molder system of claim 8 , wherein the fluid comprises air or a liquid.
10. The blow molder system of claim 1 , wherein the operating cost data comprises incremental costs to make changes to the blow molder input parameters of the blow molder, wherein the incremental costs are based, at least in part, on the energy costs for operating the blow molder.
11. The blow molder system of claim 1 , wherein the set of blow molder input parameters comprises a change to at least one of the following operating parameters of the blow molder:
pre-blow timing;
pre-blow pressure;
power levels for individual heater elements of the plurality of molds;
preform temperature set points;
stretch rod timing; and
blow pressure.
12. The blow molder system of claim 1 , wherein the inspection system comprises a material distribution sensor system for sensing a material distribution characteristic of the plastic objects.
13. The blow molder system of claim 12 , wherein:
the blow molder produces plastic containers from plastic preforms;
the desired characteristic comprises a desired characteristic of the containers produced by the blow molder; and
the plastic objects comprise the plastic containers produced by the blow molder.
14. The blow molder system of claim 13 , wherein the material distribution sensor system comprises at least one emitter-detector pair, wherein an emitter of the emitter-detector pair emits light energy and a detector of the light energy pair detects light energy.
15. The blow molder system of claim 14 , wherein the at least one emitter-detector pair comprises a plurality of emitter-detector pairs, wherein the emitter of each emitter-detector pair emits light energy toward the containers and the detector of each emitter-detector pair senses light energy that passes through at least one sidewall of the containers.
16. The blow molder system of claim 1 , wherein the inspection system further comprises a crystallinity sensor for sensing a crystallinity level of the plastic objects.
17. The blow molder system of claim 1 , wherein the inspection system comprises a camera.
18. The blow molder system of claim 1 , wherein the blow molder sensor comprises a sensor selected from the group consisting of:
an oven temperature sensor;
individual mold temperature sensors for the plurality of molds; and
a blow pressure sensor.
19. The blow molder system of claim 1 , wherein the energy costs comprise electricity costs for a plant where the blow molder is located.
20. The blow molder system of claim 1 , wherein the plastic objects comprise polyethylene terephthalate.
21. The blow molder system of claim 1 , further comprising an ambient temperature sensor for sensing an ambient temperature of a plant in which the blow molder is located, wherein the blow molder controller is further configured to determine the set of blow mold parameters based on temperature data from the ambient temperature sensor.
22. The blow molder system of claim 21 , further comprising a moisture sensor for sensing a moisture level of the plant in which the blow molder is located, wherein the blow molder controller is further configured to determine the set of blow mold parameters based on moisture level data from the moisture sensor.
23. The blow molder system of claim 1 , further comprising a plant moisture sensor for sensing a moisture level of a plant in which the blow molder is located, wherein the blow molder controller is further configured to determine the set of blow mold parameters based on moisture level data from the plant moisture sensor.