polymer processing

The leading container leak detection systems are manufactured as a complete functional package with self-calibrating microprocessor and adjustable stand-strand conveyor or indexing rotary table. Leak detection systems may be equipped with one or up to four leak detection heads and require specific adjustments depending on the container design and production rate requirements. Most systems are programmable allowing the fill value and inspection time to be tailored and can accommodate a wide range of container sizes. Additional programmable functions allow the inspection cycle to be adjusted to Trimmer speeds or Blow Molding machine cycle time. The systems include an LCD display that indicate accepted and rejected containers in total and accepted containers as a percentage. Initial adjustment procedures include centering the leak detector nose cone assembly over the opening of the container, adjustment of the relative height of the nose cone assembly on the column stand and adjustment...

Following is a extruder startup procedure for a wheel blow molding machine: 1. Turn on the plant chilled or tower water supply to the extruder heat exchanger and extruder feedthroat. 2. Turn on the power at the PLC wheel drive cabinet by raising up the handle in the top right corner. An audible alarm will sound. 3. Push the reset button that is located in the middle of the cabinet door. The button will illuminate. 4. Go to the PLC monitor and wait momentarily for the computer to boot up. 5. Press the ACK and the RESET touch button on the screen . This will silence the alarm. 6. Press the touch button that reads HYD. WATER HEATS in the lower left corner. A start screen will appear. 7. Press the start touch buttons for the pump heats only. 8. Press the MAIN touch button in the top right corner to return to the main screen. 9. Verify that the green lights below the water and heats label on the screen are illuminated. This indicates an “on” condition. 10. Press each individual extruder...

C - If any data points are outside the control limits, treat them as a special cause. Caution: with 3 sigma limits, 3 out of 1000 times will not be a special cause, but 997 times out of 1000 it will be! P - Since the data should be normally distributed about the mean, look for any non-normal patterns. The easiest way to do this, is to divide the distance between the UCL and the mean or the LCL and the mean into 3 equal parts or zones. - If about 68% of the data points fall within the first zone above and below the average, then there are no special causes. - If there are more than 68% (say 90%) or less than 68% (say 45%) then there are special causes acting on the process. R - If there is a consecutive run of 7 points in a row above or below the mean, treat the 7 or more points as a special cause, i.e., the process has "shifted". Think of it as flipping a coin and getting 7 heads in a row. A very unlikely event!! (Actually, only 8 chances out of 1000!)

The tenth step in validating a injection mold with the overall process shown in injection mold validation flow chart is Qualification (Process Capability Study) . The steps before: 1. Mold certification 2. Dry cycle mold 3. Process stability test 4. Gage repeatability & reproducibility (R&R) test 5. Mold viscosity test 6. Balance of fill analysis 7. Gate Freeze Test 8. Commissioning (multi-cavity analysis) 9. Design of Experiments (DOE or DOX) Purpose: The purpose of the qualification study is to determine if the process can meet the specified key part tolerance ranges. The first mold being manufactured to produce a molded part might be made “metal safe”. In this case, the qualification step will determine how much metal needs to be modified in the mold. Resin and colorant properties also need to be evaluated so that process capability may be determined. Once a process has been selected from performing the Design of Experiments (DOE or DOX) , the qualification study needs t...