Al & Cu FOIL THERMAL STRAPS (CuFS®)

Gold Plated Copper Foil Thermal Strap


Generally, thermal straps made with copper cables offer the best overall flexibility-to-thermal-conductivity ratio, and the lowest cost of any metallic strap configuration (to learn more about which strap configuration best meets your needs, visit our Thermal Straps page).

However, there are instances where flexibility is not needed in all 3 axes, and tight packaging constraints (limited volume), low operating temperatures, and high thermal conductance requirements, may make an OFHC copper foil thermal strap (CuFS®) a superior alternative to cu rope or carbon straps.

Cu_Foil_Strap_2-resized-600

Though TAI offered (limited) custom CuFS® products since 2014, we now offer our first standard line, the “F-series.” As with our popular CuTS® products, because TAI actually makes the straps we sell, customers are no longer limited to simple, rectangular end fittings/terminal blocks (commonly associated with outsourced, welded foil straps from machine shops in the US and Asia).  Come back this fall for pictures of TAI's new straps!

While we are rolling out our new catalog and standard line, please feel free to contact TAI about any custom CuFS® program you may have.  To discuss your CuFS® inquiry or to place an order, contact our Director of Business Development, Tyler Link.

Pictured (Top Right): LAB GRADE Gold Plated Copper Foil Thermal Strap (November 2018). Pictured (Left): Custom Foil Thermal Strap (July 2013). 

 

CuFS® Standard Product LineFlexible Thermal Links - Copper Foil Thermal Strap F5-501

TAI now offers 6 standard models, and our full line of 24 standard models (and the new CuFS™ Catalog), will be introduced in 2019.  TAI provides our newest copper thermal strap products in 3 fixed widths, with multiple thickness, installation configuration/design options, and with many of our popular end fitting designs. Just like our cabling/rope straps, these straps can be manufactured and shipped more quickly than custom straps (4 - 6 weeks on average).

All Straps are Length and Bolt Pattern Customizable at NO CHARGE.

Standard Models:

CuFTS F5-501

Details on the 24 models that comprise the F5, F6, and F7 series will be added to this page in the summer of 2018---Our apologies for the delay; we've been a little busy filling orders for our popular CuTS® products, and rolling out our new PGL and GTL lines.

Pictured (Right Top and Bottom): F5-501 with custom bolt pattern (April 2018).

 

Comparison of Thermal Conductivity

OFHC Copper Thermal Conductivity Graph

 

 Thermal Straps

Pictured (Top Left):  conductivity graph of typical cryogenic thermal strap materials. (Top Right): F5-501 CuFS® pre-conductance test and shipping (April 2018).

 

ALUMINUM FOIL THERMAL STRAPS 

Thermal Straps__A5-501 AlTS and F5-501 CuFS

Because 1100 Al has roughly one third the density of copper and half the thermal conductivity, intrinsically there is a mass benefit of up to one third less for aluminum compared to copper straps. While our CuTS® and X-Series® products are often a better substitute for an Aluminum Foil Thermal Strap (AlTS™), there are some airborne and spaceflight applications which may benefit from an AlTS™ solution (particularly those that are extremely mass sensitive, operating at 50 - 70K, and with a relatively small amount of heat to dissipate).
 
TAI now offers custom and standard model AlTS™.  Like the F-Series Copper Foil Straps, all standard model AlTS™ are available in our 0.5", 1.0" and 2.0" wide models (our A5, A6, and A7-Series), with 0.001" stacks of Al1100 foils.  They are length and bolt pattern customizable, and standard orders ship in just 6-7 weeks, while customs ship in 7-8 weeks. 
Pictured: A5-501 and F5-501 Thermal Straps being prepared for shipping (December 2018).
 

 

Limitations to Consider

While aluminum foil-based straps can be an ideal solution in certain airborne and spaceflight applications, they have largely been replaced by TAI's CuTS® and PGL™ products.  This is because our copper rope straps provide superior thermal performance and flexibility (at a lower unit cost), and our pyrolytic graphite film straps, TAI's X-Series® PGL™ (while slightly more expensive), offer superior thermal performance, at a small fraction of the mass of an equivalent aluminum link (down to operating temperatures as low as 50K).  Furthermore, TAI's PGL™ products are made using the industry's highest performing carbon material at cryogenic temperatures.
 
Because 1100 Al has roughly one third the density of copper and half the thermal conductivity, intrinsically there is a mass benefit of up to one third less for aluminum compared to copper straps. However, there are a number of other factors to consider including:
 
1)      Aluminum straps will occupy twice the volume of copper straps for the same thermal conductance.
2)      Aluminum straps are limited to stacked-foil configurations that do not provide good flexibility on each axes. This means that curvature must be included in the thermal strap design to permit directional flexibility between the strap ends. When this is done, more mass and volume are added to the strap in order to maintain a specified thermal conductance, thereby reducing any benefit over copper braided thermal straps.
3)      Aluminum readily forms an oxide that can greatly degrade thermal performance at interface locations without proper surface passivation measures.
4)      Aluminum foil straps are far more expensive than TAI's CuTS®, and competing AlTS are the same price as TAI's GFTS® products.
5)      Aluminum straps have more handling and integration constraints than copper rope straps.
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