Electric machines have significantly improved the energy efficiency from the injection molding industry over the past 20 years. New strategies to save energy whilst keeping costs down during periods of rising energy costs is the necessity of the hour. Melt-stream heating, particularly from the barrel, presents a robust prospect. Typically, 30-70% of the power consumed by band heaters is wasted by radiation and convection on the surrounding environment. Eliminating these losses will reduce specific energy usage and allow machines being pre-heated faster utilizing the same power delivery infrastructure, thereby reducing downtime to improve productivity. Inherent characteristics of band-heaters also hamper temperature control response, limiting improvements partly-to-part quality uniformity and efforts to lower change-over times. A band heater’s temperature must first rise above that from the barrel just before the barrel might be heated, and conversely, a band-heater’s temperature must fall below those of the barrel prior to it being cooled. The thermal mass of band-heaters and also the thermal contact resistance between them as well as the barrel, therefore significantly boost the thermal inertia of the melt stream. The recent introduction of lower weight radiant heating elements provides a chance for improvement. Another new technology that offers significant advantages is noncontact induction. Barrel heating using helical induction coils has become considered for many years, but was poorly applied. Past efforts often used inefficient low-frequency power supplies and constantly position the coils in direct exposure to the barrel, undermining the compelling great things about induction. Heat generated within the barrel was still capable to escape to ambient and also the coils’ thermal mass wasn’t taken from the equation. Experience of the recent barrel also increased the coil’s electrical resistance & reduced efficiency gains.
Xaloy nXheat™ induction barrel heating (patent pending) sharply cuts energy costs and improves temperature control for better quality and much less scrap in comparison with conventional heater bands. The nXheat ™ barrel heating solution (patent-pending) uses an optimized high-frequency power supply and a thermal insulating layer interposed in between the barrel and coils to address the above issues and exploit the complete potential of induction. Each of the heat is generated directly within the barrel and remains during this process. The coil’s thermal mass is additionally eliminated, and coil resistive losses are negligible therefore the exterior surface is cool to touch. Barrel heating efficiency approaches 100 % and temperature control response is quite a bit improved.
Energy savings for barrel heating of up to 70% compared to heater bands
• Additional energy savings – upto 35% more – because of reduced air cooling load
• Additional energy cost reduction from reduced peak power demand
• Fewer heater failures to cut downtime and maintenance costs
• Immediate cooling and heating solution to improve quality and reduce scrap
• Quicker heat-up, typically 2X or higher, to enhance productivity
• More heating capacity- typically 3X higher wattage in the barrel- eliminates a bottleneck
• Higher barrel temperature ability to mold high-temperature polymers, or metal
• Cool exposed surfaces for increased operator safety
The nXheat™ system uses a high-frequency power source and helical induction coils to create heat directly inside the barrel wall. A thermal insulating layer is interposed involving the coils and barrel to combat heat loss, increase efficiency and improve control response.
The machine can be found in two forms:
1) all-zone nXheat™ by which induction heating completely replaces conventional heater bands;
2) nXheat-Hybrid™ where power-saving induction technology heats the barrel’s feed zone while conventional band heaters handle downstream zones.
All-zone nXheat™ delivers maximum savings in power consumption, about 50-70%. This is basically the ideal system for larger machines exceeding three heating zones due to high worth of the lowering of power consumption.
On smaller machines with two or three zones the nXheat-Hybrid™ system can deliver many of the savings from the all-zone system because induction can be used inside the barrel’s feed zone where the greatest volume of heat input is needed to start the melting process. On such machines, which normally have barrels with inside diameters of 50 mm or less, the hybrid system will typically give a 30 to 50% decline in power consumption.
Inside the hybrid system, downstream zones dexmpky42 use either insulated or uninsulated band heaters. Greater energy savings are achieved by using insulated band heaters. The identical sheet insulation that is used within the induction-heated feed zone can be used to wrap the downstream band heaters. The precision and fast response of induction heating in the feed zone will also substantially reduce temperature overshoot conditions that can take place with insulated band heaters.
The program will cover itself with power cost savings as well as other cost and quality benefits. Some examples are reduced scrap stemming from less variation in melt temperature and faster solution to changes in target melt temperature. The payback period on investment costs of these systems is extremely reliant on electricity rates, machine size and production schedule (hours of operation per year). Such a system typically costs about 25-50% of the all-zone system.