A hot runner mould keeps the plastic molten all the way to the part, so there is little or no runner to cut off, regrind or throw away. We design and build hot runner injection moulds in Ahmedabad for high-volume products such as food containers, IML containers, glasses and ice cream cups, from single-cavity moulds up to 16-cavity production moulds.

Every mould is trialled before dispatch, and you receive videos and photos of the trial and the moulded parts.

How a hot runner mould works

In a cold runner mould, the plastic travels from the machine nozzle to each cavity through channels cut into the mould plates. That runner cools with the parts and is thrown out with them on every shot.

In a hot runner mould, a heated system inside the mould does the same job:

  • Manifold: a heated steel block that splits the flow of plastic to each cavity.
  • Nozzles (drops): carry the melt from the manifold to each gate.
  • Heaters and thermocouples: keep every zone at its set temperature.
  • Temperature controller: a separate unit beside the machine that controls each zone.
  • Valve gates (optional): pins that open and close each gate for a clean gate mark and controlled filling.

The hot runner brand, and whether we supply the controller, depend on your requirement. See where these parts sit among the other parts of an injection mould.

Hot runner or cold runner: how to choose

Hot runner Cold runner
First cost Higher: the hot runner system and controller add to the price Lower
Runner waste None or very little A runner on every shot, reground or thrown away
Cycle time Often shorter, as there is no thick runner to cool Can be set by how long the runner takes to cool
Gate mark Small; with a valve gate, clean and flat Trimmed off or broken off
Colour and material changes Slower: the system has to be purged Quick
Maintenance Heaters, thermocouples, nozzles and controller to look after Simple
Best for High volumes, thin walls, many cavities Lower volumes, frequent colour changes, a tight first budget

For three-plate moulds as well, see two-plate vs three-plate vs hot runner moulds.

When does a hot runner pay for itself?

A hot runner costs more at the start and saves something on every shot after that. To see what a cold runner would cost you, work out how much plastic goes into runners in a year:

Runner weight per shot × shots per year = plastic moulded as runner

For example, a 4-cavity mould with a 12 g cold runner that runs 1,000,000 shots a year moulds 12,000 kg (12 tonnes) of runner every year. Even if you regrind it, regrinding takes labour and power, and regrind is not acceptable for every product.

Add the cycle time a hot runner can save, and it usually pays back on moulds that run for months at a time. For short runs, frequent colour changes or a tight first budget, a cold runner is often the better choice. If you are not sure, ask us to quote both.

Moulds we build with hot runners

Every mould on our product pages can be built with a hot runner or a cold runner. Hot runners pay back fastest on thin-wall, multi-cavity disposable moulds:

Houseware, industrial and toy moulds can have a hot runner too, when the volume makes it worthwhile.

What we need for a quote

  • A drawing, a sample, or photos with the main sizes
  • The plastic material, and the grade if you know it
  • The number of cavities you have in mind
  • How many parts you plan to make in a year
  • Your injection moulding machine (clamping force and size)
  • Where a gate mark is acceptable on your part
  • Any hot runner brand you prefer, and whether you already have a temperature controller

Every quote includes a free DFM review of your part. See how we work on plastic mould design and DFM review.

Looking after a hot runner mould

  • Follow the heating and shut-down order in the operation manual that comes with the mould.
  • Do not leave the system heated for long without moulding: plastic held hot for too long can degrade and cause black specks.
  • Purge thoroughly when you change colour or material.
  • Watch the zones on the controller. A zone that will not hold its temperature usually means a heater or thermocouple needs replacing.

Questions after delivery? Call or WhatsApp us on +91 99258 10161.

Frequently asked questions

An injection mould with a heated manifold and nozzles inside it. They keep the plastic molten all the way to the gate, so little or no runner is moulded and thrown away with the parts.

Yes. The hot runner system and its temperature controller add to the first cost of the mould. It saves plastic, and often cycle time, on every shot, so it pays back on high volumes. If you are not sure, ask us to quote both a hot runner and a cold runner version.

We build moulds from a single cavity up to 16-cavity hot runner production moulds. The right number depends on the size of the part, your yearly volume and your machine.

It depends on your requirement. The hot runner system, and whether we supply the temperature controller, are chosen for your part, material and budget. Tell us if you prefer a brand or already have a controller.

A hot runner nozzle with a pin that opens and closes the gate on every shot. It leaves a small, clean gate mark and gives better control of filling, which is why it is often used on the base of cups and glasses.

Usually, yes, if the machine has enough clamping force, shot size and space for the mould. A hot runner also needs a temperature controller for its heating zones; we can supply one if you need it. Send us your machine details and we design the mould to fit it.

Yes. We have shipped moulds to Africa, Nepal, Sri Lanka and the USA, by sea or air, with trial videos and photos before dispatch.

Get a quote for a hot runner mould

Send your drawing or sample on WhatsApp (+91 99258 10161), email info@hitbhavmould.com, or use the form below. We reply Monday to Saturday, 10:00 to 19:00 IST. Buying from abroad? See export orders.

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