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1. Background for Glass Packaging

• Glass is 100% recyclable and can be reused infinitely without quality loss.
• Advantages: strong, durable, chemically inert, impermeable to gas/water, ideal for long-term storage.
• Disadvantages: brittle, heavy, sensitive to thermal shock, possible ion leaching (important for pharmaceuticals).
• Types of pharmaceutical glass:
  • Type I (borosilicate): most durable, but costly.
  • Type II (soda lime sulphated): reduced alkali solubility, hazy appearance.
  • Type III (soda lime standard): lower standard, still widely used.

2. Raw Material

• Main ingredients: silica sand, soda ash, limestone/dolomite, alumina, colorants.
• Cullet (recycled glass) 30–50% helps save energy and cost.
• Functions:
  • Silica: base material.
  • Soda: lowers melting point.
  • Calcium: increases hardness & chemical durability.
  • Alumina/Boron: improves strength, thermal shock resistance.
  • Decolorizers & colorants: adjust clarity and produce colors (flint, amber, green, blue, red, opal).

3. Container Design & Tolerance

• Cylindrical, rounded shapes are common for easier forming, strength, and high-speed filling.
• By product type:
  • Carbonated drinks: cylindrical, curved bottles to withstand pressure.
  • Semi-solids (paste): wide-mouth jars.
  • Granules/powder: wide jars with airtight seals.
• Key parts: finish, neck, shoulder, sidewall, heel, base.
• Tolerance examples: volume, diameter, height, verticality – controlled by standards.
• Decoration: stippling, frosting, screen printing, labeling.

4. Manufacturing Process

• Steps:
  1. Cullet collection & treatment.
  2. Raw material batching.
  3. Furnace melting (1,350–1,600°C).
  4. Molten gobs cut & fed into molds.
  5. Forming methods:
     • Blow & Blow (narrow-neck bottles).
     • Press & Blow (wide-mouth jars).
     • NNPB (narrow neck press & blow – lighter bottles).
  6. Surface treatment (hot & cold coatings).
  7. Annealing (stress relief in lehr).
  8. Inspection & sorting.

5. Quality Control

• Covers: mold maintenance, raw material analysis, density, color, thickness, pressure/impact resistance, coating, thermal shock.
• Common defects: blisters, cracks, deformation, inclusions, thin walls, dirt, seams, scratches, etc.
• Defects affect safety, usability, aesthetics, labeling, and packaging efficiency.

6. Printing & Labelling

• Screen printing: sustainable (no label waste), durable, but lower resolution and hard to change artwork.
• Jet printing: higher resolution, flexible for quick content changes.
• Labelling (most common): paper/plastic/metal labels, easy to change design, compatible with auto labelling machines (hundreds → tens of thousands units/hour).
• Label styles: wrap-around, front & back, shrink sleeve.