Electric machines have significantly improved the energy efficiency of the injection molding industry over the last two decades. New methods to save energy and maintain costs down in times of rising energy costs is the need of the hour. Melt-stream heating, particularly in the barrel, presents a strong prospect. Typically, 30-70% of your power consumed by heater band is wasted by radiation and convection on the surrounding environment. Eliminating these losses will reduce specific energy usage and allow machines to get pre-heated faster utilizing the same power delivery infrastructure, thereby reducing downtime to enhance productivity. Inherent characteristics of band-heaters also hamper temperature control response, limiting improvements to some extent-to-part quality uniformity and efforts to minimize change-over times. A band heater’s temperature must first go above that from the barrel just before the barrel may be heated, and conversely, a band-heater’s temperature must fall below that of the barrel before it can be cooled. The thermal mass of band-heaters and also the thermal contact resistance between them along with the barrel, therefore significantly raise the thermal inertia from the melt stream. The recent introduction of lower weight radiant heating elements provides a chance for improvement. Another new technology that provides significant advantages is noncontact induction. Barrel heating using helical induction coils has been considered for decades, but was poorly applied. Past efforts often used inefficient low-frequency power supplies and try to position the coils in direct experience of the barrel, undermining the compelling features of induction. Heat generated inside the barrel was still able to escape to ambient and also the coils’ thermal mass wasn’t taken from the equation. Connection with 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 contrast to conventional heater bands. The nXheat ™ barrel heating solution (patent-pending) uses an optimized high-frequency power source along with a thermal insulating layer interposed involving the barrel and coils to deal with the above mentioned issues and exploit the full potential of induction. Each of the heat is generated directly throughout the barrel and stays in the process. The coil’s thermal mass is additionally eliminated, and coil resistive losses are negligible therefore the exterior surface is cool to the touch. Barrel heating efficiency approaches 100 % and temperature control response is quite a bit improved.
Energy savings for barrel heating as high as 70% compared to heater bands
• Additional energy savings – upto 35% more – on account of reduced air cooling load
• Additional energy cost reduction from reduced peak power demand
• Fewer heater failures to reduce downtime and maintenance costs
• Immediate cooling and heating reply to improve quality and lower scrap
• Quicker heat-up, typically 2X or more, to enhance productivity
• More heating capacity- typically 3X higher wattage into the barrel- eliminates a bottleneck
• Higher barrel temperature power to mold high-temperature polymers, or metal
• Cool exposed surfaces for increased operator safety
The nXheat™ system relies on a high-frequency power source and helical induction coils to produce heat directly within the barrel wall. A thermal insulating layer is interposed between your coils and barrel to combat heat loss, increase efficiency and improve control response.
The device can be purchased in two forms:
1) all-zone nXheat™ where induction heating completely replaces conventional heater bands;
2) nXheat-Hybrid™ through which 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 the ideal system for larger machines exceeding three heating zones because of the high value of the decline in power consumption.
On smaller machines with a couple of zones the nXheat-Hybrid™ system can deliver most of the savings from the all-zone system because induction is utilized within the barrel’s feed zone where the greatest volume of heat input is required to start the melting process. On such machines, which usually have barrels with inside diameters of 50 mm or less, the hybrid system will typically give a 30 to 50% lowering of power consumption.
Inside the hybrid system, downstream zones dexmpky42 use either insulated or uninsulated band heaters. Greater energy savings are achieved if you use insulated band heaters. A similar sheet insulation that is utilized from the induction-heated feed zone enables you to wrap the downstream band heaters. The precision and fast response of induction heating inside the feed zone may also substantially reduce temperature overshoot conditions that may appear with insulated band heaters.
The device will pay for itself with power saving money and also other cost and quality benefits. These include reduced scrap stemming from less variation in melt temperature and faster response to alterations in target melt temperature. The payback period on investment costs for these systems is highly dependent 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.