A medical device manufacturer recently wasted $28,000 on ill-fitting blister trays because they guessed their cavity dimensions. The truth? Perfectly sized custom blister packaging isn't about trial-and-error—it's science. Use this foolproof method to calculate your ideal cavity specs before tooling begins.

• Step 1: Map Your Product's Critical Dimensions

For accurate thermoformed blister cavities, measure:

• Maximum height (H): Include any protruding parts (e.g., syringe plungers)

• Base footprint (L×W): Add 2-3mm clearance for easy loading

• Undercuts: Flag any reverse-tapered sections needing clamshell packaging instead

Pro Tip: For irregular shapes like orthodontic blister trays, create a 3D scan for precision.

Step 2: Factor in Material Behavior

Different blister packaging materials require unique allowances:

• PVC blisters: Add 12-15% to depth for material shrinkage

• Rigid PETG trays: Only 5-8% expansion needed

• Anti-static foils: Extra 1-2mm clearance for protective coatings

Use our interactive cavity calculator (linked below) to auto-adjust for your material choice.

Step 3: Optimize for Production & Function

Final checks before approving custom blister tooling:

• Draft angles: Minimum 3° for easy release (5° for textured tamper-evident blisters)

• Wall thickness: 0.015"-0.040" depending on material (thinner for eco-friendly blister packs)

• Sealing flange: 5mm minimum for consistent blister sealing films

Test Your Knowledge:

(Embedded interactive tool: Drag product dimensions to see real-time cavity visualizations)

Mastering these calculations eliminates costly redesigns and ensures your pharmaceutical blister strips, electronics blister trays, or retail clamshells perform flawlessly. Remember—the right dimensions impact everything from production speed to shelf appeal.