| Selection question | Carbon-fiber proposal | Glass-fiber proposal |
|---|---|---|
| Material identity | Specify carbon grade and tow or fabric | Specify glass grade, sizing and reinforcement format |
| Stiffness and mass | Ask for directional component data | Ask for the same geometry or an explicitly redesigned part |
| Electrical requirement | Check conductivity and isolation at interfaces | Require finished-part insulation evidence where needed |
| Manufacturing | Confirm layup, cure and quality controls | Confirm reinforcement placement, cure and quality controls |
| Commercial scope | Separate material, tooling, scrap and inspection | Compare the same accepted part and order quantity |
Separate fiber data from laminate data
Toray publishes distinct carbon-fiber grades and modulus families. That grade-level information is useful for specifying reinforcement, but it is not the allowable property of a finished laminate. Request the supplier's reinforcement schedule, resin and tested specimen configuration. Compare measurements taken in the direction that matters to the component.
Evaluate the joint and service environment
Ask the designer to review how loads enter the part through bolts, bonded joints and supports. Include electrical isolation, moisture, temperature and contact materials in the comparison brief. A material change can alter the connection details even if the external dimensions remain unchanged. Obtain a documented disposition for those interfaces before purchasing a replacement material.
Ask for two controlled proposals
Give both bidders the same functional requirements and quantity. Allow each to propose a suitable construction, but require drawings, finished mass, qualification scope, production method and tooling cost. Evaluate the accepted component cost instead of comparing fiber price alone. Use a representative trial part to resolve fit, finish and inspection questions before committing to production.
Sources and scope
These references support the stated technical context. The purchasing checklists are GetFRP recommendations. Manufacturer documents do not certify other suppliers' products.
- Toray: carbon-fiber grades and technical resources
Carbon-fiber grade distinctions; not finished-part design allowables.
