Moulds for Pharmaceutical and Electrical Components



Pharmaceutical packaging and electrical components look very different, but their moulds have a lot in common. In both cases a small defect matters: a closure that doesn't seal can spoil a medicine, and a void in an insulator can fail under voltage. Both sectors also depend on consistent parts in large numbers. This post looks at the mould types each sector uses in India and the design points that deserve extra attention.

Part 1: Moulds for pharmaceutical components

Typical parts

  • Bottles for tablets, syrups and liquids
  • Caps and closures, including threaded and tamper-evident designs
  • Jars and wide-mouth containers
  • Measuring cups, dropper parts and small device housings

Mould types used

Blow moulds make the containers. Small, precise pharma bottles are often made by injection blow moulding, which forms the neck with injection-moulding accuracy before the body is blown. Larger or clear PET bottles are usually stretch blow moulded.

Injection moulds make the closures. Threaded caps are commonly released by rotating cores, which is the job of an auto-unscrewing injection mould driven by a motor, servo, hydraulic unit or rack and pinion. Multi-cavity layouts, often with hot runners, suit the high volumes typical of closures.



Design points for pharma moulds

Auto-unscrewing injection mould with a row of threaded cores driven by a geared motor on one side and a hydraulic unit on the other

  • Neck and thread accuracy: the bottle neck and cap thread must match every time, across every cavity, so the closure seals and opens with the intended torque.
  • Cavity-to-cavity consistency: filling lines are set up for exact weights and dimensions, so drifting cavities cause line stoppages.
  • Surface finish and steel: polished cavities in corrosion-resistant stainless mould steels such as S136 help keep parts clean and the tool in good condition.
  • Clean running: designs that limit grease near the moulding area and allow easy cleaning suit hygienic production.
  • Documentation: pharma buyers usually want trial reports, dimensional records and material details for their own quality files.

See our pharma and medical moulds page for the relevant mould families.

Part 2: Moulds for electrical components

Typical parts

  • Coil bobbins and transformer insulation parts
  • Current and potential transformer (CT/PT) bodies
  • Insulators, bushings and switchgear components
  • Electrical housings and junction boxes

Why thermosets, and why the moulds differ

Many electrical parts use thermoset materials, such as DMC, BMC, phenolic, melamine and epoxy, because they keep their shape under heat and offer good dielectric strength. Unlike thermoplastics, thermosets cure through a chemical reaction in a hot mould. That changes the tooling:

  • Heated, not just cooled: compression and transfer moulds are held at curing temperature, so even heating across the tool is essential.
  • Wear resistance: mineral- and glass-filled compounds are abrasive, so hardened steels and well-supported parting faces are the norm.
  • Venting: curing releases gases, and poor venting leaves voids and blisters that can weaken insulation.
  • Flash control: clean shut-offs reduce deflashing work on every part.

Open current transformer APG mould plate showing the machined cavity and guide pins

APG moulds for instrument transformers

Automatic pressure gelation (APG) is widely used to encapsulate current and potential transformers in epoxy. Resin is fed into a heated mould under pressure. It gels from the hot mould walls inward, while continued pressure feeds material to make up for shrinkage. The mould must hold the internal windings in exactly the right position and heat evenly, so that the casting is free of voids and cracks.

At Madhav Plasto Mould, our CT APG moulds are built for epoxy-encapsulated metering and protection CTs. Alongside them we make DMC coil moulds, epoxy casting moulds for insulators and bushings, and compression and transfer moulds. See the full picture on our electrical and power industry page.

What both sectors should share with their mould maker

  • Part drawing or 3D model, with critical dimensions marked
  • Exact material grade, including filler content for thermosets
  • Annual volume and target cavity count
  • Machine or press details
  • Any testing the parts must pass, such as seal, torque or electrical tests

Need a mould for a pharma or electrical part?

Madhav Plasto Mould designs, machines and trials moulds at Bakrol GIDC, Ahmedabad, for manufacturers across India. Lead time for a complete mould is 5–10 weeks, with the exact figure set by the part's complexity. Send your drawing through our contact page, or call or WhatsApp +91-7383314026.

 

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