Rexolite® Machining & Material Properties

Wall Thickness & Part Geometry

• Favor uniform wall thickness wherever possible to minimize internal stress and warpage during machining.
• Avoid very thin, unsupported walls on large parts. Use ribs, fillets, and gradual transitions instead of sharp corners to reduce cracking risk.
• For acoustic or RF lenses, keep transitions smooth and avoid abrupt section changes that can introduce reflections or local stress concentrations.

Tolerance & Surface Finish Expectations

• Set realistic tolerances based on part size. Tight features (bores, interfaces) can often be held to a few thousandths of an inch, but global flatness and parallelism should be looser on larger parts.
• Specify RF-critical surfaces explicitly so they can be machined and finished with appropriate tooling and feeds.
• Avoid over-constraining dimensions that do not affect electrical or acoustic performance. This keeps cost and scrap under control.

Rexolite® is a relatively easy-to-machine, rigid dielectric material, but it behaves differently from metals or tougher engineering plastics. Process control is critical to avoid chatter, surface defects, and stress-related failures.

Chatter & Dimensional Instability

• Pitfall: Chatter on thin walls, long features, or lightly supported parts can leave poor surface finish and shift critical RF or optical dimensions
• Prevention:
  • Use sharp, positive-rake carbide tools and conservative step-downs to reduce cutting forces.
  • Optimize fixturing with full support under thin sections and minimize tool overhang to improve rigidity.
  • Adjust spindle speed and feed to keep a consistent chip load and avoid dwelling in the cut.

Polishing & Surface Finish

• Pitfall: Over-aggressive polishing or incorrect abrasives can round edges, change optical curvature, or leave micro-scratches that impact RF and acoustic performance.
• Prevention:
  • Define critical surfaces (lenses, RF interfaces, sealing faces) and apply controlled multi-step finishing only where needed.
  • Use fine-grit abrasives and progressively finer compounds, checking geometry against drawings during the process.
  • Avoid excessive localized pressure or heat during polishing to prevent distortion or surface haze.

Crazing, Cracking, & Heat Management

• Pitfall: Crazing or micro-cracking can occur if Rexolite® is machined with dull tools, excessive heat, or aggressive coolants and solvents.
• Prevention:
  • Maintain sharp tooling, light cuts, and proper chip evacuation to keep cutting temperatures low.
  • Use air blast or compatible coolants. Avoid aggressive solvents that can attack the material.
  • Design toolpaths to minimize re-cutting chips and reduce rubbing, which generates unnecessary heat.

Holding Tight Tolerances Without Over-Stressing The Part

• Pitfall: Forcing parts in fixtures or chasing unnecessary micron-level tolerances can introduce internal stress that shows up later as warp or dimensional drift.
• Prevention:
  • Use conformal soft jaws or vacuum fixtures where appropriate to distribute clamping loads.
  • Focus tight tolerances on function-critical features and keep non-critical dimensions more forgiving.
  • Allow parts to relax between roughing and finishing operations on large or complex geometries.

Protecting Optical & RF-Critical Features

• Pitfall: Handling and secondary operations can nick edges, scratch surfaces, or contaminate RF and optical features.
• Prevention:
  • Mask or protect finished critical areas during subsequent machining steps.
  • Use clean, lint-free handling practices and dedicated packaging for finished Rexolite® components.
  • Inspect critical features under appropriate lighting or metrology (e.g., optical comparators, profilometry) before shipment.