Making the PNGV Super Car a Reality with Carbon Fiber: Pragmatic Goal or Pipe Dream?

The Cost of Automotive Polymer Composites: A Review and Assessment of DOE's Lightweight Materials Composites Research

“…In comparison, assembly of the steel unibody accounts for about 28% of the total cost. Due to the relatively smaller cost contribution, the effect of a reduction in assembly time from 30 minutes to 5 minutes, which might come from an alternative bonding approach, has been found to be relatively weak in the BIW designs considered here (Dieffenbach 1996a). However, for the specific BIW designs considered in this study as discussed in Figure 5, this reduction in assembly time would help in getting the cost of composite monocoque BIW within $500 of the conventional steel unibody BIW.…”

“…The monocoque BIW design of composites has been found to be cost effective only because parts consolidation results in only a small number (~2-20) of relatively large parts. Figure 1 shows a recent study's cost comparison of two composite monocoque BIW designs (i.e., glass fiber-reinforced thermoset and carbon fiber-reinforced thermoplastic) against the conventional steel unibody for an annual production volume of 250,000 parts (Dieffenbach 1996a). From the cost perspective, these two composite cases provide the two extreme points.…”

“…A recent economic analysis examined two representative continuous fiber-reinforced thermoplastic composite parts (i.e., a body panel and a structural wing having weight reduction potential of 42% and 57%, respectively) made of polyamide (nylon-12)-reinforced with 50 volume % glass fiber (Hartmann 1998). The analysis indicates that even with optimizing processing technology that reduces costs by 30-40%, the economic viability of thermoplastic * The value here is the ratio of the part's cost difference to its weight savings, with the steel unibody as the baseline Source: Dieffenbach et al (1996a) composites remains a concern. The cost of materials always is a long-term major obstacle to additional improvements, as the materials contribute more than 50% of total cost even for a production volume greater than 100,000 parts/year.…”

“…The cost of the carbon fibers dominates the raw material cost of composites, for example, it accounts for over 80% of the total cost at a fiber loading of 41% by weight for carbon fiberreinforced thermoplastics considered earlier in Figure 1. To be competitive with the conventional steel unibody, it is estimated that the cost of carbon must be $7.50/lb if used at 16% volume (i.e., a volume 50% less than glass fibers) (Dieffenbach 1996a). If more carbon fibers are needed, i.e., 25% volume (or 20% less than glass fibers), then the carbon fiber price was calculated to be $1/lb for carbon thermoplastics to be competitive.…”