What are the advantages of metal 3D printing in the cooling system of injection molds?

1. A huge gain in cooling efficiency: from "linear cooling" to "fitting cavity"
The traditional injection mould cooling system usually uses a straight or cross drilling design. The cooling pipeline has trouble reaching the mould cavity's complicated curved surface, which means that local hotspots (like thin walls and corners) don't get enough cooling, and the overall cooling time has to be lengthened to keep the temperature even. For instance, making automobile bumpers with deep recesses or complicated ribs using typical cooling systems can add 20% to 30% to the cycle time and 40% to 60% to the energy use.
Layer by layer stacking makes metal 3D printing possible. You can make spiral, dendritic, or conformal cooling water channels that fit the shape of the mould cavity. This makes sure that the space between the cooling medium and the mould surface is the same all the way around (with an inaccuracy of less than 0.5mm). This gets rid of the "cooling blind spots" that straight holes can't cover. As an example, B&J Specialty's automotive pipeline mould shows how 3D Systems' ProX® The DMP 300 machine manufactured conformal cooling inserts, which cut the cooling time from 60 seconds to 40 seconds. This made production 30% more efficient. The mold's surface temperature also changed less, going from 132 °C to 18 °C. This greatly lowered the chance of warping.
The conformal cooling water circuit can also improve the distribution of flow velocity through fluid dynamics simulation, which is even more significant. For instance, a certain electronic case mould uses a variable cross-section design (with an inlet diameter of 8mm and an end diameter of 5mm) to keep the mold's surface temperature differential under ± 3 °C. Traditional moulds, on the other hand, normally have a temperature difference of ± 8 °C. This even cooling helps lower internal tension in injection-molded parts, which can make them stronger and last longer.
2. Whole life cycle cost optimisation: going from "high initial investment" to "long-term benefits"
The initial cost of metal 3D printing equipment (like SLM Solutions equipment, which costs about 5 million yuan) and metal powder materials (like martensitic stainless steel, which costs 800-1200 yuan/kg) is relatively high. However, their full lifecycle cost advantages become very clear in mass production:
Improvement in the rate of material use: The use rate of traditional subtractive manufacturing materials is less than 45%. However, "near nett forming" technology has raised the use rate of 3D printing materials to almost 85%. For instance, a company that makes parts for aeroplanes employs 3D printed cooling inserts, which cut the amount of material used from 12 kg to 3.2 kg and the cost per piece by 73%.
Lowering energy use and maintenance costs: Improving the cooling efficiency cuts the amount of cooling medium needed by 30% to 50% and also makes the refrigeration unit work less hard. If you have an injection moulding project that makes 1 million pieces a year, cutting the cooling time for each item by 10 seconds can save you around 2777 hours a year, which is the same as adding 1.5 units of equipment capacity.
Extending the life of a mould: Uniform cooling cuts down on mould thermal fatigue damage, which can add 20% to 30% to the mold's life. Traditional moulds last about 500,000 times, but 3D printed moulds can last 600,000 to 700,000 times, which lowers the cost of the mould for each injection moulded product by a lot.
3. There are endless ways to innovate structures, from "simple pipelines" to "functional integration."
Metal 3D printing gets over the structural problems that traditional cooling systems have and makes the following new designs possible:
Microchannel cooling: SLM technology can print cooling channels with diameters as small as 1.4mm, which allows for very precise thermal control. For instance, the microchannel design of a medical catheter connector mould makes cooling 60% more effective while avoiding difficulties with degradation that might happen when cooling is not enough.
3D printing may combine high-strength steel and high-thermal conductivity alloys (like copper alloys) to make gradient material structures. A specific 3C electronic mould uses a cooling water circuit made of stainless steel and copper. This circuit has a thermal conductivity that is 2 to 3 times greater than that of ordinary H13 steel and a cooling efficiency that is 40% higher.
Integration of breathable function: The third-generation breathable steel method of laser can make a 0.04mm aperture and allow air to flow in all directions, getting rid of the problem of gas being stuck in moulds. By adding a porous layer to the bottom of the rib plate, a specific gas-assisted forming mould lowers the surface shrinkage rate of injection moulded parts from 8% to less than 2%.
4. The future of intelligent adaptation will go from "experience-driven" to "data-driven."
The smart improvement of cooling systems is being driven by the combination of metal 3D printing and digital technology.
Optimising simulations closed-loop: Software like Cimatron and Moldex3D can be used to simulate the cooling path, which can help you guess how the temperature will spread out and improve the design. After bringing the mould files from Cimatron into Moldex3D, B&J Speciality engineers were able to lower the temperature change by 86% and cut down on the number of mould trials through simulation.
Adaptive cooling control: The 3D printing cooling system can check the mould temperature in real time and change the cooling settings as needed when used with IoT technology. A German mould maker has improved the cooling efficiency of its online systems by putting sensors in the cooling water circuit. This has cut equipment downtime by 60%.
Ability to quickly iterate: During the new product development phase, 3D printing helps speed up closed-loop optimisation of "design print test iteration." A new company that makes battery modules for electric vehicles used 3D printing to make cooling plates and went through three rounds of design changes in three days. This made the cooling system 35% more efficient.