Parametric injection molding system and method

• US 20060012064A1
• Filed: 07/19/2004
• Published: 01/19/2006
• Est. Priority Date: 07/19/2004
• Status: Active Grant

• Current Assignee: Baxter International Inc., MKS Instruments Incorporated
• Original Assignee: Baxter International Inc., Umetrics AB (Sartorius AG)
• Inventors: Wold, Svante, Hutson, Lee Merrill
• Granted Patent: US 7,465,417 B2
• Time in Patent Office: Days
• US Class Current: 264/40.100
• CPC Class Codes: B29C 2945/76006 Pressure
• CPC Class Codes: B29C 2945/7604 Temperature
• CPC Class Codes: B29C 2945/76066 Time
• CPC Class Codes: B29C 2945/7611 Velocity
• CPC Class Codes: B29C 2945/7619 barrel
• CPC Class Codes: B29C 2945/7621 nozzle
• CPC Class Codes: B29C 2945/76307 hydraulic fluids
• CPC Class Codes: B29C 2945/76381 Injection
• CPC Class Codes: B29C 45/1769 Handling of moulded articles or runners, e.g. sorting, stacking, grinding of runners
• CPC Class Codes: B29C 45/768 Detecting defective moulding conditions B29C45/84 takes precedence

Abstract

The present invention provides a method and system for controlling the quality of a product produced by an injection molding production process. The invention includes performing a multivariate analysis on injection molding process data collected real-time and determining whether the real-time data is within a predetermined production control limit. When the real-time production data exceeds the control limit, the process is considered out of control and product produced during the out of control condition is removed real-time from the injection molding production process.

Claims

1. A method of controlling the quality of a product produced by an injection molding process comprising:

generating an injection molding process model from injection molding process data, the injection molding process model having a control limit;

collecting real-time injection molding process data;

determining whether the real-time injection molding process data is within the control limit; and

removing the product from the injection molding process when the real-time data process data exceeds the control limit.

2. The method of claim 1 wherein the determining and the removing occur substantially simultaneously.

3. The method of claim 1 wherein the injection molding process data and the real-time injection molding process data are selected from the group consisting of cycle time, melt temperature, fill time, melt pressure, cool time, pack time, mold temperature stationary, mold temperature moveable, injection time, hold time, shot velocity, shot cushion, fill pressure, pack pressure, hold pressure, back pressure, machine decomposition, hydraulic transfer pressure, position transfer, barrel temperatures, nozzle temperature and combinations thereof.

4. The method of claim 1 further comprising storing the injection molding process data in a database.

5. The method of claim 1 wherein the generating of an injection molding process further comprises the step of performing a multivariate analysis on the injection molding process data.

6. The method of claim 5 wherein the performing of a multivariable analysis is selected from the group consisting of performing a principal component analysis, calculating a Hotelling T² value, calculating a DModX value, performing a projection to latent structures analysis, and combinations thereof.

7. The method of claim 1 comprising the step of transforming the injection molding process data into at least one surrogate variable and calculating a Hotelling T² value and a DModX value for the at least one surrogate variable.

8. The method of claim 7 wherein the control limit is defined by the Hotelling T² value and the DModX value for the at least one surrogate variable.

9. The method of claim 8 comprising the step of calculating a Hotelling T² value and a DModX value for the real-time injection molding process data and comparing these values to the control limit.

10. The method of claim 9 wherein the control limit is exceeded if either the Hotelling T² value the DModX value for the real-time injection molding process data exceeds the Hotelling T² value or DModX value for the at least one surrogate variable.

11. The method of claim 1 further comprising the step of adjusting the control limit by combining the real-time injection molding process data to the stored injection molding process data and performing a multivariate analysis on the combined injection molding process data.

12. The method of claim 11 wherein the collecting the real-time injection molding process and adjusting the control limit occur substantially simultaneously.

13. A method for parametrically releasing a product produced by an injection molding production process comprising:

collecting real-time production data from the injection molding production process;

comparing the real-time production data to a predetermined production control limit;

determining whether the real-time production data is within the predetermined production control limit; and

removing from the injection molding production process any product produced when the real-time production data exceeds the control limit.

14. The method of claim 13 wherein the determining and removing occur substantially simultaneously.

15. The method of claim 13 wherein the injection molding production process proceeds during the removing.

16. An automated system for controlling the quality of a product produced by an injection molding production process comprising:

a data analysis module for generating a predetermined injection molding production control limit;

a data collection device for collecting real-time injection molding production process data;

a prediction module for determining whether the real-time injection molding process data is within the control limit; and

a diversion device in operative communication with the prediction module, the diversion device removing from the injection molding production process any product produced when the real-time injection molding production process data exceeds the control limit.

17. The system of claim 16 further comprising a controller in operative communication with the prediction module, the controller sending a signal to the diversion device when the real-time injection molding process data exceeds the control limit.

18. The system of claim 16 further comprising a transporter for removing the product from the injection molding machine.

19. The system of claim 18 wherein the diversion device further comprises a gate that removes product from the transporter.