Hot Runner Systems in Injection Molding: Ultimatum Guide

Hot Runner Systems in Injection Molding- Ultimatum Guide

In today’s world, those who make and shape things need to find ways to lower the cost and time it takes to make them. Usually, to stay competitive in the market, hot runner suppliers offer many solutions to deal with the situation.

Usually done to deal with competition and fulfill client needs simultaneously. There are three types of frameworks in this space: pre-made, adjustable, and personalized.

Therefore, you must determine which hot runner is the most cost-effective to meet your needs. How do you choose the right one when too many choices are available?

So, this blog reveals complete information about hot runner systems that are available nowadays. And talks about the advantages of using a hot runner system, how to pick a good one, and other important things to know. Just stay tuned with us!

What is a Hot Runner Injection Molding System?

What is a Hot Runner Injection Molding System

Now, we’ll go into detail about the Hot Runner Systems. The Hot Runner system melts plastic with heat and then pushes it through tiny tubes to create a variety of shapes out of plastic.

Engineers use heat to melt plastic and turn it into a liquid. The hot plastic goes through thin lines to various parts simultaneously. These lines are called runners and are associated with the trim machine.

Hot Runner vs. Cold Runner Injection Molding Systems

Companies can choose between two methods for plastic injection molding: hot runners or cold runners.

The systems for hot and cold runners are different. Hot runners can directly inject plastic into the product. This method keeps the channels hot while injecting. Only a piece is removed every time.

Also, you can quickly use the mold again by cycling it. This helps things look nicer by making them smooth and detailed with a small injection spot.

Using hot runner systems is a great way to create many products quickly without creating a lot of waste. It’s also great for making a high amount of products.

And when we talk about cold runners, they are not cost-saving compared to hot runners. Although, hot runners have higher costs than cold runners. Cold runners have complicated layouts and a costly waste of resin.

Hot Runner vs. Cold Runner Injection Molding Systems

Cold runners produce more waste, making leftover plastic, taking off extra bits/de-gating, taking more time, and problems with looks and shape than hot runners.

When making plastic things, the cold runners use a special channel called a sprue to inject plastic into the other channels. As the name suggests, the plastic gets cool in a system of channels that are not heated.

It hardens in the holes and channels where the molten material flows. You need to cool and take away the extra plastic after each turn, which makes the turn take longer.

Also, plastic things made with cold runner systems have more imperfections because they have bigger openings called gates where the plastic goes in. Now, it is important to understand what each system can do well and what it cannot do well. Because every system can do various things.

How Does a Hot Runner Injection Molding System Work?

When using a hot runner system, the plastic in the tubes stays soft and doesn’t get hard. You can do things quicker by doing them faster.

The system stops people from throwing away too much plastic by keeping it in liquid form until it’s ready to be molded. Taking away the sprue system makes the finished product smoother because there is less cutting needed.

Main Components of Hot Runner

Hot runners are complex systems that must maintain a consistent temperature throughout the plastic mold so it can continue to be shaped, while also cooling the surrounding area so the plastic can harden quickly. The most vital pieces of the framework are the nozzles, manifolds, and links.

  • Nozzles or Spouts are the way to measure how deep something is. They connect to either the main part or a smaller part that goes into a hole.
  • Manifolds are tools used to hold, and guide melted plastic from a container to different spout openings. They come in different shapes and can also be made to fit specific needs.
  • Flow control jobs use valve technology to manage the flow of liquid plastic out of a nozzle.
  • Connections or Links are created within the system to provide function. They have different connections like electricity, temperature, water, air, and coolant.

Benefits of Hot Runner Molds

Benefits of Hot Runner Molds

There are a number of benefits that come with the hot runner system. Hot runners are now favored by many for the production of plastic molds and manufacturing. While using a cold runner is still necessary, using a hot runner has numerous advantages in various industries.

Flexibility in Design

People use hot runners in different ways. This thing is very important for many reasons. Having many options when using hot runners is great because it makes them more appealing.

Placing the gate in the best spot helps make the product look good and fills it well. Using edge gating, hot tip gating, or valve gating can all cause the same outcome.

You can use the Runner that heats up with different shapes of molds. Entryway adaptability helps make molds more straightforward to cool and improves the trim interaction.

Improved Molding System

The improved molding system makes it simple to start hot runner molds. After a shot that has not been filled, there are typically no particular runners that need to be eliminated. Until a planner gets a total image of the shape.

You should be aware that the mold can be utilized once the system reaches a sufficient temperature. By injecting materials with less stress, businesses can perform better.

Shape and plate bending and cutting caused by expanding materials will both be reduced as a result of this.

Automating the Process of Shaping Materials

Automating the Process of Shaping Materials

Mold Automation Hot Runner’s flawless flash-free plastic components also help with mold automation. The shape tools won’t get caught on runners, so the part will be consistent in size. Many companies are using machines to make plastic products and put them together.


Even though using a hot runner may cost more at first, it will end up saving money in the long run. Both the length of the production cycle and the amount of plastic waste produced during processing have decreased. As a direct result, productivity has increased.

High Quality of the Parts

Stopping the cold runner helps to improve how the material is pressed and filled. If something loses weight, it can cause dents on surfaces and parts that are not filled with material. The hot runner keeps the same heat when filling and packing things in the molds, starting from the opening to the end.

This affects people who want to use very specific spaces to get good quality and precision. If a hole in the mold gets broken or doesn’t work right, it’s easier to fix it so it doesn’t make bad parts or get too hot.

Reduce Cycle Time

Reduce Cycle Time

Usually, half of the injection’s total weight is made up of the cold runner’s density. Usually, it’s thicker than the wall of the molded part. If you use a hot runner instead of a cold runner, you can make the process faster.

The thickness part controls how long the cooling takes. That’s why it’s important. Moreover, because the hot runner has a smaller amount of liquid plastic, it helps to make the injection happen faster.

It also makes it easier for the injection screw to recover, helping to save time.

Runner Elimination

Companies are starting to use fancy materials more often because it’s getting more expensive to buy them. The cold runner costs more and is not like the hot runner. In hospitals or clinics, you must recognize that a damaged IV tube cannot be used again.

There are a few reasons why this might happen, like when it costs a lot to make something smooth again, and it makes loud sounds and dust. Also, it costs money to store things, and there are other things to think about too.

When making lots of things at once, like injection molding, recycling leftover materials can be hard. Hot runner systems have solved the problems of regrinding and expenses due to a shortage of runners.

Loopholes of Hot Runner

The hot runner system is a good choice, but people who make molds should know its problems too. By learning more about hot runner systems’ disadvantages, this section helps people choose the best one for their projects.

Great Care

Great Care

Hot runners need great care, meaning they require a lot of attention and care to keep working well or looking good. Using and taking care of the hot runner system can be hard.

If you don’t deal with it right, the hot runner can break because it’s very difficult. If things don’t work out, the business might lose a lot of money.

Need for Advanced Equipment

The usage requirements for hot runners are extremely stringent. To ensure hot runner molds function well, you must consider using specific machinabilities. These machines must work together perfectly.

If we don’t have everything we need to make a part, it could cause big problems when we’re making it. And if the plastic cover is not working properly, too much-melted plastic can harm the parts that carry the melted plastic.

If the nozzle and gate aren’t located correctly, it can ruin the end product.

Thermal Expansion & Contraction

There are lots of different hot runners that come in all sorts of shapes and sizes. Some hot runners shrink and expand when they get hot or cool down. Because of this reason, engineers always produce heat during the process. Controlling the heat given off when making something is hard to do.

Extra Care for Heat-Sensitive Resin

If you use a hot runner system for delicate plastics, you have to be careful and know more about it. If people don’t do the right things, bad things could happen.

The decrease might look like a little color change or be difficult and have to do with how the molecules are linked together. So, be extra cautious with resin that can be damaged by heat.


Hot runner parts cost a lot of money. As a result, buying a hot runner mold is getting more expensive. Moreover, if a company can’t produce a lot, it may not make sense or be necessary to use a hot runner system because it could be too expensive.

In poorer countries, people don’t use hot runner systems much because they are too expensive.

Price of Hot Runner Systems

Price of Hot Runner Systems

Although Hot Runner systems have benefits, they are costly. As we said before. A hot runner manifold usually costs $20,000 to $30,000. You also need to spend $5,000 more for the controller if you need it. If there are more sections in the manifolds, then the system will cost more money.

These zones are where hot liquid plastic goes into something. People sometimes call them drops. The system’s capacity to fill multiple cavities simultaneously increases with the number of drops.

What’s more, it prompts a proportionate expansion in the general expense of the framework. It is very important to know about these expenses. You should know these expenses are like an investment.

Types of Hot Runner Systems

There are two kinds of Hot Runner Systems: valve gate and hot tip. Also, the main contrast between the two is the method for infusing things. Before going on, we should comprehend the valve gate and hot tip.

What is the Hot Tip?

The Hot tip is an important setup and form of hot runner setup. The valve gate system is thought to be more expensive than the most common hot runner system. A hot tip is good for making lots of simple things quickly.

What Is a Valve Gate?

A valve gate is an infusion point that points to a mechanical valve. The valve gate closes when the machine injects plastic into a shape or mold. It closes quickly and leaves no marks or scratches on the item’s surface.

Producers use valve entryways for things that request high flawlessness and an incredible look and aesthetic. If you use it, then you will know that it is expensive.

Internally Or Externally Heated

Usually, the hot runner has two kinds. They both use two plates that are heated up by a complicated system. Heating molds from far away lets you use delicate materials that can’t handle too much heat.

If you warm up the molds from the inside, you can have more control over how the materials move. Hot runners come together from inside and outside heat designs. Since remotely heated runners typically disperse and control heat better, internal heated frameworks have largely become out of date.

In exchange for a higher price and a more complicated plan, heated runners boast superior warm conveyance over insulated runners. The type of material and what it’s used for will help you decide which one is better.

Insulated Runners

They are less expensive to build and have a simpler design than heated runners. Plus, they experience problems with uniform shape filling, freeze-ups at the entrance, and lengthy start-up periods for stabilization. Also, they need a fast process to keep the plastic soft.

Kemal Services

Kemal Services

Kemal offers really good plastic injection molding services to the whole world. We provide a complete system for creating fabric. This includes checking the fabric, making the tools, creating parts, finishing the product, and doing the final check.

Further, we provide a comprehensive manufacturing plan that takes into account every aspect of the manufacturing process, from the initial confirmation of raw materials to the creation of devices to the production of parts to the final evaluation.

Our team is experienced, and we are very good at responding quickly to our customers.  You should approach us because we can make custom plastic objects using a molding process, put together the finished products, and come up with new product ideas according to your requirements.

You can trace us at for further queries.


A hot runner system makes different plastic things by sending melted plastic into many shapes. Infusion molding is when plastic is kept liquid by heating it in a special container.

It makes things quicker and cheaper by using less plastic and saving energy.

People prefer hot runner molds because they can produce things quickly and with better quality than cold runner molds.

Although they may be more expensive at first and require regular upkeep, hot runner systems do not produce any trash. This means they can save money in the long term.

Problems with running usually happen in three areas. The most important things to consider are the diameter of the gate, the nozzle orifice’s size, and the gate land.

There are two types of hot runners, ones that get hot from far away (externally) and ones that get hot from the inside (internally). Heating molds from a distance is better for materials that can’t handle too much heat.

But, Keeping molds warm from the inside is a better way to manage how the material moves through them.

To make sure the melted plastic flows evenly. The hot runner molding tool keeps melted plastic at a very exact temperature. The plastic spreads out smoothly and breaks into pieces that are the same size everywhere.

Sum Up

Hot runner technology has helped make injection molding better. It improved the way things are made by controlling how things melt and are handled, making better quality parts, and more things can be made at once.

Because they function better, hot runner systems are superior to cold runner systems. So, big money can be saved by using less tar, making the production process go faster, and doing extra work after it’s finished. You can make hot runners different ways to work for different things.

The industry that makes molded products is improving by using hot runners instead of cold runners and by improving hot runner technology.

Plastic factories have new problems to deal with as they make things that are more complicated and use less plastic.

Hot runner systems are being used to solve these problems. We want to use better technology for delivering melted material in injection molding. This will become more important in the future.

Put your parts into production today

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