Post bonding

Cladding and backing metals are purchased in the appropriately heat-treated condition because corrosion resistance is retained through bonding. It is customary to supply the composites in the as-bonded condition because hardening usually does not affect the engineering properties. Occasionally, a post-bonding heat treatment is used to achieve properties required for specific combinations. 

After a satisfactory verification film is produced, an assembly may be fabricated specifically for destructive inspection to validate that the verification film was accurate. This correlation allows the use of verification film rather than more expensive destructive inspection for future changes such as duplicate tool fabrication and tool or detail modification. Simple assemblies are usually not destructively inspected because of high confidence that the verification film is entirely representative of the expected bondlines. Complex or large parts may not be destructively inspected because of the cost of the details and assembly time. In these cases other means of validating the verification film are used. Meticulous pre-bond detail and post-bond assembly thickness measurements may be sufficient to prove bondline thickness control. Ultrasonic inspection and X-ray photography (discussed previously) may be sufficient to prove that details are in the correct places and bonds are good. 

Adhesive that bridges package posts or is on the post bond area. 

The development of methods for post-bonding quality assurance might also be added to these faetors, since a barrier to the general introduction of structural adhesives into construetion is the lack of a reliable method of assessing the quality of bonded joints. 

If the adhesive layer was always to represent the weakest link in the joint, the quality of the assembly would be limited to an assessment of the cohesive properties of that layer. Unfortunately it is the interface which tends to be of greater concern because it is here that joint failure is more commonly encountered, particularly after ageing. The most useful tests for indicating interfacial quality are in fact pre-bonding surface inspection procedures, which can nevertheless suggest potential joint performance. The tests used for assessing cohesive properties of the adhesive layer must necessarily be post-bonding activities. 

The measurement of the strength of adhesion between adherend and adhesive requires a measurement of the intermolecular forces of attraction this is not currently possible. This aspect of quality control is therefore essentially reduced to assessing the adherend surface characteristics prior to bonding, although some post-bonding simple mechanical tests are appropriate. 

GATE POST BONDED TO MAT TYPIOAL BOTH SIDES OF GATE... 

Post bond treatments treatments such as machining, painting, anodisation or electroplating should not affect bond performance. 

ASTM D429-02, Method D, Post Bond Vulcanisation butt test [16]. Parts are clamped in a jig and put into an autoclave or oven. 

Modeling the chemical bond is certainty a major key for describing the chemical reactivity and molecular structures stability. Yet, since the chemical bond is a dynamic state, for the best assessment of its connection with the stability and reactivity, the pre- and post-bonding stages are naturally considered the present discussion follows (Putz, 2010a). 

FIGURE 4.2 Heuristic representation of the concept of atoms-m-molecule (AIM) compactness aromaticity (for the benzene pattern) as the ratio of the pre- and postbased molecule to the (vis-a-vis) post-bonding molecular orbitals (MOL) modeling (Putz, 2010a). 

The two molecular perspectives may be associated with the pre- and post- bonding stages of chemical bond at equilibrium therefore, the... 

Formulates two complementary pictures of chemical aromaticity, by relative compactness and absolute difference between the atoms-in-molecules and molecular orbital stages of pre- and post-bonding in a molecule, so contributing to deeper understanding of chemical bonding itself as a d5mamic competition of atoms in molecule with molecular orbitals as a whole ... 

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