PEEK Machining & Supply for San Antonio Aerospace and Medical

PEEK, polyether ether ketone, is the polymer engineers reach for when ordinary plastics fail and metal is overkill. It keeps useful mechanical properties continuously at temperatures around 250 C, with a glass transition near 143 C and a melting point above 340 C, far beyond what nylon, acetal, or polycarbonate can survive. It resists most chemicals, hydrolysis, and steam, and it carries inherent flame resistance with low smoke and toxicity. For San Antonio's aerospace work, that combination means PEEK can replace metal brackets, bushings, connectors, and clips while cutting weight and eliminating corrosion. In medical devices it offers biocompatibility, the ability to survive repeated autoclave sterilization, and in implant grades, compatibility with the human body. Those are demanding application spaces, and PEEK is one of the few polymers that qualifies for both. The trade-off is cost and processing. PEEK is expensive relative to standard engineering plastics and requires careful machining or molding discipline to realize its properties. Buyers specify it deliberately, on parts where its temperature and chemical performance genuinely earn the premium rather than as a default plastic.

Unfilled PEEK is the natural grade, often a tan or beige color, and it offers the best ductility, impact resistance, and elongation of the family. It is also the grade most relevant to medical and food-contact work because it is available in compliant and implantable formulations. When a part needs toughness, electrical insulation, or biocompatibility rather than maximum stiffness, unfilled PEEK is the starting point. Glass-filled PEEK, typically 30% glass fiber, trades some toughness for much higher stiffness, dimensional stability, and improved resistance to creep and wear. It holds its shape better under sustained load and heat, which suits structural brackets and components that must keep tolerance in hot environments. The glass makes it more abrasive to machine and somewhat more brittle, but for many aerospace structural plastic parts it is the right balance. Carbon-filled PEEK, usually 30% carbon fiber, pushes stiffness and strength higher still while adding thermal and electrical conductivity and reducing wear in sliding applications. It is the choice for bearings, bushings, and wear components, and its conductivity helps dissipate static where that matters, such as around semiconductor handling. Carbon fiber raises cost and abrasiveness, so it is reserved for parts that genuinely need its mechanical or wear performance.

PEEK machines well compared to most high-performance plastics, but holding tight tolerances takes discipline because it is sensitive to heat and internal stress. As a semi-crystalline thermoplastic, PEEK can move dimensionally if machining heat or residual stress is not managed, so precision parts often benefit from annealing the stock before and sometimes during machining to relieve stress and stabilize dimensions. For San Antonio shops cutting PEEK for aerospace connectors or medical components, the practical guidance is sharp tooling, moderate speeds, good chip clearance, and attention to heat. Filled grades, especially carbon and glass, are abrasive and wear tooling faster, so carbide tooling and managed feeds matter. Coolant choice also matters on medical and food-contact parts, where contamination from cutting fluids must be avoided, sometimes pushing shops toward dry machining or compliant coolants. The payoff is that PEEK can hold genuinely tight tolerances and fine finishes when handled properly, which is why it can directly replace machined metal parts. Buyers should ask prospective shops about their experience with PEEK specifically, including whether they anneal stock, since a shop that treats it like generic plastic will struggle to hold tolerance on a stable, repeatable part.

PEEK's two biggest San Antonio markets, aerospace and medical, each bring their own qualification overhead, and that paperwork is part of the sourcing equation. For aerospace, parts often need AS9100 traceability, material certification to the specified PEEK grade, and sometimes flammability or outgassing data, since PEEK's low smoke and toxicity is a selling point on interior and confined-space components. For medical devices, the bar is ISO 13485 and biocompatibility documentation. Medical-grade and implantable PEEK formulations are distinct from industrial grades, and the supply chain for them is tightly controlled with full lot traceability. A shop serving San Antonio's medical-device base needs to handle that documentation and material control, not just machine the part. The common thread is that PEEK rarely ships as an anonymous commodity part. Whether it's going on an aircraft or into a surgical instrument, buyers should expect to specify the exact grade, require certification, and confirm the supplier can produce the traceability the application demands. Settling these requirements before the first chip is cut prevents a well-made part from being unusable because the documentation doesn't exist.