Joseph I. Dougherty President IPR
Tooling plays a critical role in manufacturing quality tablets, requiring care in handling, cleaning, inspecting, measuring, and storing. Documenting these maintenance steps improves efficiency, quality, and compliance. Creating a tool management system helps streamline these activities
Identify and Document
First, identify the documents and information that accompanies the life cycle of tablet tooling followed by the management of inspection and measurement data. Specialized systems can aid in the tooling management and inspection.
Establishing user requirements and a project plan will help ensure a successful installation and startup. Key components include identification of critical records, inspection methods, data management, reporting, and compliance. Critical documents associated with tablet tooling include the upper punch drawing, lower punch drawing, die drawing, and tablet drawing.
The tooling vendor typically provides these drawings. But the tablet manufacturer must consider where the drawings are stored and how they are traced to associated tooling, for several reasons. First, the drawings define the measurement tolerances for new tooling. Second, drawings have a life cycle in terms of revisions and obsolescence.
Linking tooling sets to a revised drawing can prevent issuing the wrong set of tooling to production, and identifying obsolescence enables destruction of sets that are no longer in use. It’s also important to consider the type of inspections and corresponding measurement data. The most critical tooling measurement is working length, as the variation in a tooling set impacts tablet weight control, especially for smaller tablets.
A simple method for measuring working length is using an indicator on a height stand, but this requires operator interpretation for tool position and orientation. Measurement fixtures can improve efficiency and repeatability, helpful for higher volume tooling measurement requirements or multi-tip tooling applications.
Additional measurements include:
- Tip & Die Diameter – Enables identification of tip wear and tip to die clearances
- Tip Concentricity – Enables identification of bent tips
- Die Bore – Enables identification of wear and potential issues with tablet ejection
- Overall Length – Identifies potential issues with tablet take-off due to length variation
- Barrel Diameter – Identifies the proper barrel diameter per tablet press model and turret configuration
- Embossing – Identifies wear and potential issues in tablet coating or tablet identification
The Tablet Specification Manual, written by the APhA Tableting Specification Manual Steering Committee, provides guidance for determining required tooling measurements and inspection methods. Tooling identification must be considered to enable tracking of measurement and inspection data. Tooling vendors provide etching on punch necks and die faces to include unique identification information, and part numbering methodology should be considered to ensure compatibility with an inspection system.
Tracking and Tracing
Tooling sets should be identified and tracked for inventory, inspection, usage, and reporting purposes. Both tooling identification numbers and tooling set numbers should be traced to tablet and tooling drawings, and recorded. Also, establish a re-inspection schedule for tracking usage and wear. Establish usage tolerances to help determine end of tooling life. Tracking set usage enables predictive planning.
Furthermore, re-inspection and tracking set usage enables performance monitoring of tooling revisions such as changes in tool steel, coatings, or minor tablet design revisions such as increased lands or embossing changes to try to prevent picking and sticking. Reinspection also aids in reworking tooling, because the process helps identify working length variances before and after grinding the head flats or grinding/ stoning punch tips.
Use of digital or analog measuring devices enables electronic measurement interface for data collection to improve efficiency and accuracy—eliminating paper records, but requiring electronic record management, which includes specific compliance considerations. Weigh the type of data interface and repository to meet data integrity requirements.
Getting Visual
Visual inspection is an important aspect of tooling inspection as it can identify issues not easily measured. Some key aspects of tooling that should be visually inspected include:
- Punch Face – Inspect lands to look for wear or curled tips, inspect for cracks, wear, or dents from mishandling, identify proper embossing per tablet drawing
- Punch Head Wear – Inspect punch heads for pitting, inspect punch head inside angle for wear • Punch Tips – Inspect for side tip wear, mushroomed or curled tips
- Die Bore – Visually inspect for die bore wear
Visual inspection can also provide an excellent aid for tool orientation during measurement, which eliminates operator subjectivity. Graphic overlays can establish an orientation template associated to a tablet drawing. Images of the visual inspection can provide a historical reference and excellent communication reference with the tooling vendor.
Digital Demands
Collecting and measuring data electronically enables storage in a central repository, which, in turn provides reporting capabilities. Employing an SQL database enables data queries and off-the-shelf inspection systems provide standard reports. Some useful reports include inspection results, matching of punch working lengths to optimize press setup, working length variance reports to identify tools that may require rework or reject, set usage to determine end of life or selection of sets to issue based on use, and inventory management. Access to inspection management records should be restricted to authorized users, and record-locking capabilities allow multiuser and multi-site access.
Utilization of electronic records requires adherence to 21 CFR Part 11 for Electronic Records; Electronic Signatures. A summary of requirements is listed in Table 1.
Electronic systems require both Initial and periodic testing of devices—such as tokens or cards—for security purposes. The operator must ensure that any item that bears or generates identification code or password information functions properly and has not been altered in an unauthorized manner. Validation of an inspection management system including installation qualification, operational qualification, and product qualification may be required. Validation protocols are often available from system providers along with installation services, validation assistance, and training. Calibration and preventative maintenance procedures should be established to maintain any system implemented, and data protection procedures should be established for backup and disaster recovery purposes.
Implementing systems that apply these standards may take time initially, but they will pay off long term, by keeping better track of tooling—and, ultimately, reducing downtime and waste.