Question: How is the ASTM D5470 test modified to characterize Phase Change Thermal Performance?
Answer: Bergquist uses the Anter Quickline 10 to characterize our ASTM D5470 test results. The method is modified to condition the phase change material to 5°C over the stated phase change temperature. Understanding that time is also a key variable for material displacement or flow, the over-temperature conditioning is limited to 10 minutes and then allowed to cool, prior to initiating the actual test at the given pressure. The 10-minute time period has been demonstrated to be an acceptable time period for the thermal mass inherent in the Anter setup. Note: Actual application testing may require more or less time to condition, depending upon the heat transfer and thermal mass associated. The performance values are recorded and published at 10, 25, 50, 100, and 200 psi to give the designer a broad-based understanding of Hi-Flow's performance.
Question: What is the minimum pressure required to optimize the thermal performance of the Hi-Flow material?
Answer: Upon achieving phase change temperature (i.e. pre-conditioning), Bergquist has demonstrated that 10 psi provides adequate pressure to achieve exceptional thermal performance. Bergquist continues to research lower pressure wet-out characteristics in an effort to minimize interfacial losses associated with ultra-thin material interfaces.
Question: Will the Hi-Flow replace a mechanical fastener?
Answer: Mechanical fasteners are required. Bergquist recommends the use of spring clips to maintain consistent pressure over time.
Question: Can I use screw mount devices with Hi-Flow material?
Answer: Hi-Flow works best with a clip or spring washer mounted assembly. The continuous force applied by these devices allows the Hi-Flow material to flow and reduce the cross sectional gap. Bergquist suggests that design engineers evaluate whether a screw mount assembly will have acceptable performance. See TO-220 Technical Note.
Question: Is the adhesive in Hi-Flow 225F-AC repositionable?
Answer: The adhesive in the current construction does adhere more to the heat sink aluminum than to the Hi-Flow material. There is the potential that the adhesive will be removed by the heat sink surface when it is removed to reposition on the heat sink. Time and/or pressure will increase the bond to the aluminum increasing the potential for the adhesive to adhere to the heat sink.
Question: Is there any surface preparation required before applying the adhesive backed Hi-Flow to the heat sink?
Answer: Standard electronics industry cleaning procedures apply. Remove dirt or other debris. Best results are attained when the Hi-Flow material is applied to heat sink at a temperature of 25° +/- 10°C. If the heat sink has been surface treated (i.e. anodized or chromated), it is typically ready for assembly. For bare aluminum, mild soap and water wash cleaning processes are typically used to eliminate machine oils and debris.
Question: Is the Hi-Flow material re-workable?
Answer: If the material has not gone through phase change, the material will readily release from the device surface. For this situation, the Hi-Flow material will not likely have to be replaced. If the material has gone through the phase change, it will adhere very well to both surfaces. In this case, Bergquist suggests warming the heat sink to soften the Hi-Flow compound for easier removal from the processor. Replace with a new piece of Hi-Flow material.
Question: What is meant by "easy to handle" in manufacturing?
Answer: Insulated Hi-Flow products are manufactured with inner film support. This film stiffens the material, allowing parts to be more readily die-cut as well as making the material easier to handle in manual or automated assembly.
Question: What is meant by "tack free" and why is this important?
Answer: Many Hi-Flow materials have no surface tack at room temperature. The softer materials will pick up dirt more readily. Softer resins are more difficult to clean if any dirt is on the surface. If you try to rub the dirt away, the dirt is easily pushed into the soft phase change materials. Hi-Flow coatings are typically hard at room temperature rendering them easier to clean off without embedding dirt.
Question: What does "more scratch resistance" mean on Hi-Flow 625?
Answer: Hi-Flow 625 does not require a protective film during shipment. There are two issues with competitors’ materials:
1. Melt point of the material is low enough that it can go through phase change in shipment and be very tacky. Hi-Flow has a higher phase change temperature and remains hard to a higher temperature.
2. The Hi-Flow material is harder and is not as easy to scratch or dent in shipping and handling.
Question: Why is our product phase change temperature 65°C?
Answer:The 65°C phase change temperature was selected for two reasons. First, it was a low enough temperature for the phase change to occur in applications. Second, it would not phase change in transport. Bergquist studies show that shipping containers can reach 60°C in domestic and international shipments. The higher phase change temperature eliminates the possibility of a product being ruined in shipment. We offer a standard line of Hi-Flow 225 and 300 series products with 55°C phase change for those customers wanting the lower phase change temperature.
Question: In which applications should I avoid using Hi-Flow?
Answer: Avoid using Hi-Flow in applications in which the device will not reach operation at or above phase change temperature. Also avoid applications in which the operating temperature exceeds the maximum recommended operating temperature of the compound.
Question: What is ISO9001:2000?
Answer: The ISO certification is the adoption of a quality management system that is a strategic decision of the organization. This International Standard specifies requirements for a quality management system where an organization: a) needs to demonstrate its ability to consistently provide product that meets customer and applicable regulatory requirements, and b) aims to enhance customer satisfaction through the effective application if the system, including processes for continual improvement of the system and the assurance of conformity to customer and regulatory requirements.