GMW GMW17622 PDF

This standard covers the requirements of body shop applied structural foams used for structural reinforcement of body cavities and other areas where structural reinforcement is required and secondary for Noise, Vibration and Harshness (NVH) reduction. These materials impart structural integrity to the parts with which they come in contact, but shall not be considered a main structural component. The structural foam part is installed in the body shop, and expands to fill the cavity when processed through Electrodeposition Priming Operation (ELPO) bake ovens. These materials may be die cut, preformed, or molded.

Material Description. Materials approved to this standard may be either tacky or non-tacky. The materials must have suitable fasteners or maintain sufficient green strength to production substrates until they are fully expanded (cured). The materials must not accelerate corrosion of the substrate with which they come in contact.

Tacky (T). Tacky foam materials may be formed into parts which are applied directly to oily metal. They must remain in position in the uncured state up to and throughout the pretreatment, ELPO and baking process.

Non-tacky. Non-tacky foam materials generally require a carrier or fastener to hold them in place in the uncured state, up to and throughout the pretreatment, ELPO and baking process. Parts made from these materials have an optimum design for corrosion avoidance when they allow sufficient clearance between the uncured part and the adjacent metal to enable electrocoat coverage behind the part.

Material Types. Material types are defined by compressive modulus at target bake conditions defined in Table 3.

• Type 1: < 250 MPa

• Type 2: 250 MPa to 450 MPa

• Type 3: 450 MPa to 700 MPa

• Type 4: 700 MPa to 900 MPa

• Type 5: > 900 MPa

Symbols. Not applicable.

Applicability. Typical applications include structural reinforcement of body cavities (i.e., pillars, rails) and other areas where lightweight structural reinforcement is desired. 1.4 Remarks. These materials are not intended to be weldable, fuel resistant, or applied in the paint shop.