Both series and parallel cooling channel connections are common practices in production plants. Each method affects pressure loss, cooling efficiency, and the overall thermal performance of the mold differently. Understanding these effects is essential for optimizing the cooling process and ensuring consistent quality in molded parts.

In a series configuration, the cooling medium flows sequentially through each cooling channel. The coolant enters the first channel, exits it, and then enters the next channel, continuing this path through all channels before returning to the cooling system. In contrast, in a parallel configuration, a manifold splits the cooling medium into multiple streams that simultaneously enter each cooling channel. The coolant is then collected back into a single stream before returning to the cooling system.

Effects of Series and Parallel Configurations

1. Pressure Losses
   • Series Cooling Channels:
     In this setup, the coolant flows through each segment of the mold in sequence. This configuration leads to cumulative pressure losses, as the fluid encounters resistance at every bend, turn, or restriction along its path. The total pressure loss in a series system can be described using the Darcy-Weisbach equation.

where:

	Pressure loss
	Friction coeficient
	Channel length
	Channel diameter
	Liquid density
	Flow velocity

Extended Flow Path in Series Cooling and Its Impact on Pressure Loss

In series cooling, the extended flow path of the medium results in greater pressure losses due to increased friction and, possibly, smaller channel and hose diameters. This can lead to higher requirements for the flow rate of the feeding pump.

• Parallel Cooling Channels:
  In this configuration, the coolant is split into multiple “branches,” each cooling a specific part of the mold. Since each channel operates independently, the total pressure loss is significantly lower, as the fluid does not need to flow sequentially through all channels.

For each branch, the pressure loss is still governed by the Darcy-Weisbach equation, but the shorter lengths and individual pathways lead to significantly reduced pressure losses. The total pressure drop in a parallel system can be modeled as the sum of pressure drops across all channels, calculated using:

2. Flow Turbulence

• Series-Connected Channels:
  The longer the fluid remains in the channel, the greater the likelihood it will transition into turbulent flow, especially if the coolant’s velocity is high or the channel diameter is small. Turbulent flow enhances convective heat transfer but at the cost of higher pressure losses and increased energy needed to pump the medium through the channels.
• Parallel-Connected Channels:
  In parallel channels, the flow is typically divided into lower-velocity streams that generally remain laminar or only slightly turbulent. This results in a more predictable and controlled flow but may lead to lower heat exchange rates if the flow rate in each branch is not appropriately regulated.

The Reynolds number Re helps determine the flow regime:

where:

Dynamic fluid viscosity

In general, turbulent flow (high Reynolds number, Re>4000Re > 4000Re>4000) enhances heat exchange but also increases pressure losses. In series channels, achieving turbulence may be desirable, whereas in parallel systems, maintaining a more laminar flow can provide better control and efficiency.

3. Heat Exchange Efficiency

• Series-Connected Channels:
  The temperature of the cooling medium rises as it absorbs heat from each successive section of the mold. By the time the coolant reaches the final sections, heat removal may be less effective due to a larger temperature differential. This can result in uneven cooling across the mold.
• Parallel-Connected Channels:
  Each channel has a more consistent coolant temperature since it flows simultaneously into each circuit. This results in more uniform cooling throughout the mold, leading to better heat management and, consequently, higher molded part quality. However, careful channel design is necessary to ensure balanced thermal distribution in the mold to avoid „dead zones” or inefficient heat removal.

The Nusselt number (Nu) is often used to quantify heat exchange efficiency:

where:

• h is the convective heat transfer coefficient,
• k is the thermal conductivity of the fluid.

In series-connected systems, the local Nusselt number will vary along the length of the connected channels and decrease as the coolant warms up. In contrast, parallel systems make it easier to maintain a more consistent Nusselt number across all channels.

4. Impact on Cooling Efficiency

• Series Configuration:
  • Temperature Gradient: The coolant passing through multiple channels sequentially absorbs heat, causing its temperature to rise. This creates a temperature gradient within the mold, where the initial channels are cooler, while the later ones become progressively warmer. This uneven cooling can lead to an inconsistent cooling rate across the molded part, potentially resulting in warping or other defects.
  • Reduced Flow Rate: The cumulative pressure loss in a series configuration can significantly reduce the overall flow rate, decreasing the coolant’s ability to absorb heat efficiently. This can lead to longer cycle times and lower production efficiency.
• Parallel Configuration:
  • Uniform Temperature Distribution: In a parallel configuration, the coolant entering each channel has approximately the same temperature, leading to a more uniform cooling process throughout the mold. This helps maintain consistent part quality and reduces the likelihood of defects associated with uneven cooling.
  • Higher Flow Rate: Since pressure losses are minimized in a parallel configuration, a higher flow rate can be maintained, enhancing heat exchange efficiency. This may result in shorter cooling times and improved production efficiency.

This post Series and Parallel Connections of Cooling Channels – Their Impact on Mold Cooling first appeared on Coolingcare.eu and is written by testadmin

What Cooling Water Parameters Should We Control to Minimize the Risk of Scale and Deposit Formation?

Optimally treating cooling water is crucial for minimizing the risk of deposits, scale, and corrosion (rust) in cooling systems. Below are the key chemical parameters that should be monitored:

1. Water Hardness (CaCO₃):
   • Optimal Range: 80-120 ppm (mg/L).
   • Excessive hardness can lead to scale formation (e.g., calcium carbonate), while very low hardness increases corrosion risk.
   • Control: Regular laboratory tests and, if hardness is too high, the use of scale inhibitors.
2. Water pH:
   • Optimal Range: 7.0-8.5.
   • pH levels below 7 can accelerate corrosion, while higher values encourage scale formation.
   • Control: Daily pH testing, with pH regulators (acids/bases) as needed.
3. Alkalinity:
   • Optimal Range: 100-300 ppm (as CaCO₃).
   • Higher alkalinity promotes calcium deposit formation, while low alkalinity may favor corrosion.
   • Control: Alkalinity testing and the addition of regulating agents as necessary.
4. Chlorine and Other Oxidizing Agents:
   • Optimal Range: 0.5-1.5 ppm for free chlorine.
   • Chlorine has antibacterial effects, but excessive levels lead to corrosion.
   • Control: Chlorine levels monitored with DPD or amperometric tests.
5. Electrical Conductivity:
   • Optimal Range: 500-2000 µS/cm (system dependent).
   • High conductivity indicates high salt concentration, which promotes deposit formation and corrosion.
   • Control: Regular conductivity measurements and blowdown (partial drainage and refill with fresh water).
6. Oxygen Content:
   • Oxygen in cooling water fosters corrosion.
   • Control: Use corrosion inhibitors (e.g., sodium sulfite) to reduce oxygen content.
7. Iron and Copper Concentration:
   • Optimal Range: <0.5 ppm for iron and copper.
   • Higher concentrations may indicate internal system corrosion.
8. Chemical Agents and Inhibitors:
   • Scale Inhibitors: Polyphosphates, organic phosphates, phosphonic acid (prevents calcium salt deposits).
   • Corrosion Inhibitors: Molybdates, nitrites, zinc phosphates, silicon compounds.
   • Biocides: Chlorine, bromine, isothiazolinones – used for biological control (bacteria, algae).
   • Dispersants: Help keep suspended particles in water to prevent sludge formation.

What Products to Use?

• Corrosion and Scale Inhibitors: Prevent scale buildup and rust formation.
• Biocides: Control microorganism growth (bacteria, algae) in the system.
• pH Regulators: Acids or bases, depending on pH readings.

For efficient and effective water treatment, regular monitoring and adjustments based on these parameters are essential to maintain a well-functioning cooling system.

This post Optimal cooling water parameters first appeared on Coolingcare.eu and is written by testadmin

When talking to customers, we always try to convince them to test the device they are interested in. We believe that before making an investment decision, the effectiveness of the solution should always be verified, especially when we are not dealing with a product that directly boosts a company’s productivity (like an additional injection molding machine, for example), but rather with a device that indirectly „unlocks” productivity and minimizes production costs.

During our visits to various companies, we often encounter competitors’ machines that, for some reason, are not being used and are left gathering dust in a corner. When we ask why the machine is not being used, we usually hear that it did not perform as expected in practice—whether in terms of effectiveness, ease of use, or reliability. This naturally raises the question of how the purchase decision was made and why the final users of the product were not actively involved in the decision-making process, or at least in giving their opinion on the solution.

Marketing departments can be very creative, writing things in brochures designed to catch the attention of a specific target group. It often turns out that a loudly promoted feature is something entirely trivial and obvious, or worse, that the so-called „automatic” XYZ device still requires frequent operator intervention during the process.

From our 7 years of experience, we’ve learned that purchase decisions made solely based on price, without considering the actual needs of the company, often result in the purchased machine being set aside and unused because it is either a) ineffective or b) impractical from the operator’s perspective. Such a purchase is a waste of money and, even worse, spoils the market, because the chance of buying another device with similar features is usually lost.

That’s why, as a manufacturer, we urge you to test, compare, and verify what you read and hear from salespeople. Remember, the most expensive machines are those that aren’t used; such an investment will never pay off. Verifying the effectiveness of a solution in your production environment will allow you to truly assess the machine’s performance, ease of use, and overall design.

This post The most expensive machine is the one you don’t use, because it will never pay off. Don’t buy a pig in a poke. first appeared on Coolingcare.eu and is written by testadmin

To minimize the risks associated with declining cooling efficiency, regular cleaning of cooling channels must be incorporated into routine mold maintenance. Here are some best practices to help keep cooling channels clean and operational:

1. Regular Preventive Cleaning: Establish a cleaning schedule based on the mold’s usage frequency and the type of coolant circulating in the system. Regular diagnostics and short preventive cleaning sessions effectively prevent contaminant buildup before it leads to more significant issues that impact the process.
2. Flow Monitoring: Implement systems to monitor the flow of the cooling medium through the channels. Early detection of flow reductions or increases in the delta T (the temperature difference between inlet and outlet) can indicate blockages or the accumulation of scale or rust.
3. Documenting Maintenance Activities: Maintain detailed records of all maintenance activities, including cleaning dates/times and flow rates recorded for individual channels. This documentation helps track cooling efficiency declines over time and can guide future decisions regarding tool maintenance.
4. Choosing the Right Tool: Ensure that the cleaning device has features that allow for efficient and thorough cleaning, as well as monitoring the performance of each cooling circuit in the tool. It’s beneficial if the device also has data logging capabilities, enabling you to review and reference the data in future cleaning sessions.

This post Best Practices for Effective Cooling Channel Cleaning first appeared on Coolingcare.eu and is written by testadmin

Neglecting regular cleaning of cooling channels can have serious consequences for both the mold and the production process. As contaminants accumulate, the flow of water becomes restricted, reducing the efficiency of the cooling system. Lower heat dissipation due to a layer of low thermal conductivity insulation, combined with restricted flow, can cause localized overheating in the mold (known as hot spots). This leads to uneven cooling and unstable part quality. As a result, the percentage of defective parts increases, production costs rise, and more frequent mold repairs or even replacements become necessary. In critical cases, the cooling channels may become completely clogged, forcing a mold shutdown, disassembly, and mechanical drilling of the blockage, which generates enormous costs. This not only increases operational expenses but also negatively affects the ability to meet production deadlines. In times when customer quality requirements are so demanding, maintaining stable part quality with the shortest possible cycle time is crucial.

Potential Problems Arising from Tool Thermal Disturbances:

1. Extended Cycle Times: Contaminated cooling channels result in slower heat transfer, meaning the mold requires more time to cool. This leads to longer production cycles, reducing overall process efficiency and increasing operational costs.
2. Part Defects: Uneven cooling can affect part quality. Defects such as warping, sink marks, and dimensional deviations become more common, leading to a higher rejection rate by quality control. Additionally, uneven cooling can create internal stresses, reducing the strength of the product and causing it to crack under load.
3. Faster Mold Wear: Reduced cooling efficiency forces the mold to operate at higher temperatures for longer periods, accelerating the wear of mold components. This can shorten the tool’s lifespan and require more frequent repairs and refurbishments.
4. Higher Energy Consumption: An inefficient cooling system requires more energy to maintain the mold’s proper temperature, leading to increased energy costs and a greater environmental impact.

This post Consequences of Neglecting Cooling Channel Cleaning first appeared on Coolingcare.eu and is written by testadmin

The mineral deposits are primarily composed of calcium and magnesium carbonates. Carbonates, which are generally insoluble, are precipitated by heating water containing soluble calcium and magnesium bicarbonates. Bicarbonate is thermally unstable and will decompose to form carbonates and thus limescale when heated.

Factors influencing scale deposition:

• The higher the (temporary) water hardness, the more scale will form.

• The higher the pH (alkaline pH) of the water, the greater the tendency to scale

• The higher the temperature to which the water is heated, the more scale build-up will be present.

Precipitation and scaling on channel walls increases dramatically when the water temperature exceeds 60 degrees Celsius. It also depends on the hardness of water, so in some areas the problems caused by limescale are greater than in others. To counteract limescale problems, most injection molders deploy some form of water treatment to minimize the risk of mineral-based deposits such as calcium or magnesium.

The DS2 cleaner is recommended to remove limescale from calcium and magnesium deposits.

Another type of deposit is formed during the corrosion process. These can be solid, water-insoluble deposits (such as incrustations during the microbial corrosion process) or scale – a layer of solid corrosion products or hard iron oxides. Like other deposits, they are dangerous to the ducts, restrict the flow and reduce the efficiency of heat removal.

Rust-based scale in the channels of water-cooled molds will typically have a high concentration of iron oxides / corrosion by-products. This is mainly because companies use „closed-loop” water systems where the concentration of iron oxide is up to seven times higher than in regular tap water. Another reason for the formation of deposits from the corrosion process may be the water left in the channels after the cleaning process. The dissolved oxygen in the water reacts with steel causing corrosion.

The DS1 cleaner is recommended for descaling with a high concentration of iron oxides.

This post Types of sediments and scale deposits first appeared on Coolingcare.eu and is written by testadmin

We see this type of connections most often in bigger molds that have a large number of cooling channels. It is impractical to connect cooling to each of the channels separately, so they are usually bundled into one manifold, the purpose of which is to supply the cooling media to the individual cooling circuits in the mold. Of course, this type of solution is not perfect. We must remember that the parallel connection of channels will typically generate various pressure drops (these drops may result from large disproportions in diameters, lengths or distances of the channels from each other, forcing them to be connected to the manifold with hoses of different length) which inevitably translate into uneven distribution of the cooling liquid to individual circuits, even if a manifold with an appropriate pressure-balancing volume is used. This solution should be treated as a compromise, as we should always try to connect channels in such a way that the risk of uneven distribution of the coolant is as low as possible. In a situation where one of the circuits is partially or completely blocked, a parallel connection will prevent the cleaning liquid from reaching this channel, because the solution will always try to find the path of least flow resistance.

However, it should be remembered that the process of cleaning the channels is not a process of cooling. This is a common misconception that people who bridge channels for cleaning use, arguing that the mold is connected in the same way during production. If we want to effectively clean the circuits connected to each other by means of a manifold, we must use a feed pump with a much higher capacity, that is able to overcome pressure drops generated by the cooling system, while maintaining the appropriate dynamics, which will guarantee the effectiveness of cleaning in the shortest possible time. The effectiveness of devices equipped with single pumps with a higher flow rate depends primarily on the number of litres of pumped liquid in a given time, which is never the most effective solution. That is why it is worth looking for solutions using hybrid systems, such as the patented, two-stage hydromechanical cleaning process in CoolingCare machines, in which two cooperating pumps for each of the cleaning sections are used. This approach gives much more flexibility and significantly reduces cleaning time.

This post A few words about parallel connections… first appeared on Coolingcare.eu and is written by testadmin

The purpose of the efficient cooling system of the mold is to guarantee an even distribution of temperatures on individual molding cavities, which translates into appropriate dimensional tolerances and the quality of injected parts.

Any temperature deviations caused by flow disturbances and / or the inability of the channels to effectively take away the heat will, over time, translate into the deteriorated quality of the manufactured product, the circulating medium circulating in the mold cooling system receives heat from it, ensuring an even temperature distribution, which in turn translates into appropriate quality, compliance with dimensional tolerances or cycle time.

Corrosion products, limescale and other deposits on the walls of the channels are the silent killer of the efficiency of our cooling system. Scale deposits reduce the efficiency of the cooling system by reducing the its diameter. Worse still, due to its very low thermal conductivity, even a thin layer of scale acts as an insulator, making it difficult to receive the heat from the molding cavity. The scale never precipitates evenly, which can quickly lead to disturbed mold thermal behaviour and quality problems. That is why it is so important to regularly monitor the cooling efficiency in our molds and act preventively.

It should be remembered that the issue of cleaning channels and maintaining high cooling efficiency throughout the life of the tool applies not only to those made in additive technologies, but also to conventional, drilled cooling channels. The only difference is that the complex geometry of the channels and the small diameters of the channels with conformal cooling make cleaning more difficult and requires the appropriate tools and methods. This does not mean, however, that classic structures with drilled channels are free from problems related to reduced cooling efficiency or clogging. It is a very common phenomenon and, worst of all, it happens imperceptibly.

This post Do you control the performance of your injection molds? first appeared on Coolingcare.eu and is written by testadmin

Every year, companies around the world unknowingly lose hundreds of thousands of Euros due to the gradual decline in cooling efficiency in their tools and machines. Lower mold efficiency, longer cycle time due necessity of counteracting dimensional deviations of plastic parts, longer mold downtimes, maintenance and servicing – all these factors increase operating costs and translate into a decrease in company profits. The source of these problems originates not only in the quality of the cooling water, but also in the processing temperatures, which translate into precipitation and gradual deposition of deposits and rust inside cooling channels of molds as well as other heat exchangers.

The rate at which mineral deposits or corrosion byproducts are deposited depends on many factors, such as the chemical composition of the cooling medium and the operating temperature. Also, the way the cooling is designed can have a significant impact on the decrease in cooling efficiency. „Dead” areas that generate zero flows will be places where the deposits precipitated from the cooling medium will naturally settle. It is important to simulate the flow of the medium at the design stage of the mold cooling, so as to avoid fundamental errors that increase the risk of a drop in cooling performance. Unfortunately, at the stage of constructing the mold, the topic of the decrease in cooling efficiency due to calcification of the system seems so distant that it is rarely taken into account.

This post Factors influencing the decrease in cooling efficiency first appeared on Coolingcare.eu and is written by testadmin

This is a question faced by companies looking for solutions to address the issue of declining cooling efficiency in tools due to gradual buildup of scale and rust deposits. The answer is not straightforward and could be summarized as „it depends.” To properly select a device that will work well in your facility, several key factors should be considered. Below, we briefly discuss each of them:

Price vs. Efficiency

Price is always a key factor in purchasing decisions, especially when multiple departments are involved in the decision-making process. It is worth looking closer at what a given price includes, as it may turn out that the capabilities and performance of a seemingly more expensive solution result in a faster return on investment than a cheaper option. This can be influenced by factors such as the number of cleaning sections or the cleaning technology itself. For example, the CA6 device, which has six independent cleaning sections, allows for an average of 240 molds to be cleaned per year, assuming that each channel is connected to the device separately (without circuit bridging). This provides six times the performance of single-circuit devices that are popular in the market. Bridging circuits for cleaning is always discouraged due to increased pressure drops, which negatively affect the pump’s dynamics and increase the risk of channel blockages. A larger number of cleaning sections gives greater flexibility, especially when each section is equipped with a dedicated set of pumps. Such a solution, of course, costs more than a system built on a single pump. The final decision is up to the buyer, but it is important that this decision is made consciously, understanding the physics and dependencies involved.

Automation of the Process and Personnel Involvement

Another factor to consider when choosing a device is the level of automation of the entire process. There are simple and inexpensive manual devices on the market that require the operator to manually set individual operations. As labor costs rise, companies are increasingly leaning toward solutions that minimize human involvement. In addition to manual and semi-automatic devices, our portfolio includes advanced units that practically reduce operator tasks to connecting the mold, selecting it from the database, and pressing the START button. Advanced algorithms carry out the entire process, from mold blowout, leak and flow tests, measurements, cleaning, rinsing, and system drying. This approach also minimizes the risk of operator errors.

Collecting data on Cooling Efficiency and Mold Condition

When choosing a device, it’s worth asking whether you’re looking for a unit that only allows cleaning or one that offers additional functions, such as flow rate measurements, leakage & blockage tests, or channel rinsing. You may even be looking for a solution that enables the collection of cooling efficiency data over the entire life of a mold, with the ability to generate reports and program the machine to reference the information in the database during cleaning sessions. Collecting information on cooling efficiency changes over time is one of the biggest added values a device can bring to a company. This allows the maintenance department to implement a preventive cleaning policy, saving a lot of time and often stress. Combining a database with intelligent machine modes, where the device can be programmed to clean until reference flow rates or stable flow rates are achieved, further saves time and eliminates the risk of damaging the tool due to overly long cleaning sessions. After all, how is an operator supposed to know how long the cleaning should take?

Safety of Operation

Often overlooked in the early stages of the purchasing process, this aspect is actually one of the most important. It’s not uncommon for molds that require cleaning to be worth hundreds of thousands of euros. Therefore, you need to be confident that in the event of an unexpected situation, such as a leak, the machine can autonomously and quickly decide to stop the process. A common solution in cheaper devices is the use of floaters, which are supposed to „guarantee” maintaining the correct amount of liquid in the tank. However, they do not protect against leaks because their response time is too slow. Therefore, it’s worth looking for solutions based on ultrasonic sensors, which, with surgical precision, control the liquid level in the tank and can respond quickly to leaks, stopping the process. This is just one example of the safety features used in the CS and CA series devices.

Process Effectiveness

All the factors mentioned above may become secondary if the cleaning process itself is ineffective. Conventional cleaning methods rely on pumping chemically active solutions through channels using either rotary or diaphragm pumps. The flow dynamics through the channel are so low that the process entirely depends on the effectiveness and aggressiveness of the selected cleaning agent, aimed at dissolving deposits. This cleaning method, combined with a lack of process automation and effectiveness monitoring, increases the risk of tool damage, as cleaning time depends solely on the operator’s assumptions. An alternative solution is cavitation cleaning, where the cleaning medium only softens the deposits, and the actual cleaning and removal of scale take place mechanically. A sudden pressure drop creates millions of vacuum bubbles, which collapse and generate shock waves, breaking up the deposit layer on the channel surface. Thanks to the incomparably higher dynamics of the process, hybrid cavitation cleaning allows for a significant reduction in the total cleaning time, which is another argument in favor of choosing this cleaning technology.

Internal Company Analysis

Finally, it is important to note that the machine that will best suit a given facility largely depends on:

• Nature of production – Whether the production is for the automotive, medical, or optical industries, where both molds and reporting requirements are very stringent.
• Number and size of molds – For larger quantities of tools and channels, devices with a greater number of cleaning sections are recommended. Choosing such a device will have a direct impact on process efficiency without the need to serially connect channels.

By carefully considering these factors, you can select the right cooling channel cleaning device that not only improves your cooling efficiency but also optimizes your overall production process.

This post How to Choose the Right Cooling Channel Cleaning Device? first appeared on Coolingcare.eu and is written by testadmin