Loading ...
Loading ...
Loading ...
3M™ VHB™ Tape 5925
Design Considerations
Adhesion to the substrate is important in achieving bonding success. Adhesives must ow onto the substrate surfaces in order to achieve intimate contact area and
allow the molecular force of attraction to develop. The degree of ow of the adhesive on the substrate is largely determined by the surface energy of the substrate.
3M™ VHB™ 5952 family tapes bond well to high (HSE), medium (MSE), and medium/low (M/LSE) surface energy materials. The image below shows typical materials
in these categories.
Achieving good contact is also important. The necessary thickness of tape depends on the rigidity of substrates and their atness irregularity. While the 3M™ VHB™
Tapes will conform to a certain amount of irregularity, they will not ow to ll gaps between the materials. For bonding rigid materials with normal atness, consider
use of tapes with thickness of 45 mils (1.1 mm) or greater. As the substrate exibility increases thinner tapes can be considered.
Using the right amount of tape is important to handle the expected stresses. Because 3M™ VHB™ Tapes are viscoelastic by nature their strength and stiness is a
function of the rate at which they are stressed. They behave stronger with relatively faster rate of stress load (dynamic stresses) and will tend to show creep behavior
with stress load acting over a long period of time (static stresses). As a general rule, for static loads, approximately four square inches of tape should be used for each
pound (57 cm² of tape per kg) of weight to be supported in order to prevent excessive creep. For dynamic loads a useful design factor is 12 lb/in2 (85 kPa) for most
dynamic stresses in general applications.
Allow for thermal expansion/contraction. 3M™ VHB™ Tapes can perform well in applications where two bonded surfaces may expand and contract dierentially.
Assuming good adhesion to the substrates, the tapes can typically tolerate dierential movement in the shear plane up to 3 times their thickness.
Bond Flexibility: While an advantage for many applications where allowing dierential movement is a benet, the tape bonds are typically more exible than alternative
bonding methods. Suitable design modications or periodic use of rigid fasteners or adhesives may be needed if additional stiness is required.
Performance in Severe Cold Temperature can be challenging. Applications which require performance at severe cold temperatures must be thoroughly evaluated by
the user if the intended use will subject the tape product to high impact stresses. A technical bulletin “3M™ VHB™ Tape Cold Temperature Performance” (70-0707-
3991-0) is available for additional information.
Loading ...
Loading ...
Loading ...