Even with the most advanced PET bottle blowmolding system, there are variations in bottle material distribution from mold to mold. Each mold performs slightly different. This can be evidenced when analyzing bottles from a mold set, in the same region, as some produce thicker and some thinner distributions. These variations can result in inconsistent
performance from bottles of the same production run, leading to potential downstream problems.
Individual Mold Control provides the ability to further optimize the blowmolding process by controlling the blow parameters for each individual mold station (in add
ition to global parameters for all molds). This capability makes it possible to minimize mold-to-mold variation in thickness distribution.
With the Process Pilot system, high-precision thickness distribution measurements are captured on every bottle. Typically the Process Pilot system manages material distribution to a base-line thickness established on an overall average of all mold stations by controlling the oven parameters and P1 pressure as well as start time. These parameters are common to all the molds and move the material distribution close to baseline to produce a consistent quality of bottles. The Individual Mold Control option takes distribution management to a new level by identifing the distribution variance from mold to mold. Using an advanced control algorithm, the Individual Mold Control option provides the means to reduce individual mold station variability by proactively adjusting the pre-blow start time of each mold station through individual mold offsets. By doing this, the material distribution can be controlled on a per mold basis. This makes it possible to achieve an overall tighter distribution model over the entire mold set, much closer to the baseline than can be provided using the global approach. Furthermore, the level of trend analysis incorporated by Process Pilot on a mold station by station approach provides valuable data for condition-based mold station maintenance.
The benefits of Individual Mold Control
There are several benefits to controlling thickness distribution on the individual mold basis. These include the following
- Reduced production variation
- Increased production days due to targeted maintenance
- Elimination of “outlier” mold-specific containers that may cause downstream issues
- Opportunities for further light weighting
Availability and compatibility
The Process Pilot with the Individual Mold Control option is compatible with rotary stretch blowmolding systems that incorporate independent mold station management. The Individual Mold Control option is currently available for KHS Series IV blowmolders. There are plans to expand the mold control option for Krones and Sidel blowmolding equipment by year end. A retrofit version is also available for Process Pilot systems currently operating in the field.
Agr’s Process Pilot Automated Blowmolder Control system has proven to be a vital tool in the production of light weight bottles, while improving overall bottle performance and quality. It is unique in that it manages the blowmolder based on direct bottle measurements, on every bottle produced. By controlling the blowmolder based on direct feedback from bottle measurements rather than just blowmolder performance indicators, the Agr system can ensure that the final product has the desired quality and performance attributes in spite of environmental, blowmolder or material variations that occur during the production process. The addition of Individual Mold Control further compliments this.