Crystallinity and tolerance
PEEK is semi-crystalline. Cooling rate changes crystallinity, and crystallinity changes shrinkage and stiffness. Medical tubing must hold crystallinity constant so properties match lot to lot, and the thinner the wall, the harder it is to hold that and the dimensional tolerance at once. ±0.03 mm is what comes out stably while keeping crystallinity; ±0.02 mm sharply raises the sorting ratio on the same line, and that shows in the price.
Small bore, square, black
Prototype quantity and quotation
PEEK tubing prototypes start at 20–40 pcs. If the size is not already in production, die (end-tip) changeover cost applies, so bundling several sizes in one inquiry lets development cost be shared. Give annual volume too and we quote prototype and production prices separately.
Straightness, tolerance, length and quantity in the first email — most of these are answered within a day.