Related tooling references: Hardened D2 Trim Die Stripper Plate CNC Tool Selection for Slug Windows and Guided Punch Bores and Aluminum Nitride Power Module Carrier CNC Tool Selection for Isolation Pockets and Fragile Ribs.
English: Delrin AF Star Wheel Tooling for Ratchet Teeth and Detent Pockets
This Delrin AF star wheel case focuses on drawing-based tool choice for ratchet teeth, detent pockets and a hub bore in PTFE-filled acetal. The search intent is not simply plastic milling; it is how to keep indexing edges sharp without whitening, fuzz or pitch error.
Star wheel features converted into polymer tooling
| Drawing feature | Chosen polished tool | Reason for the choice |
|---|---|---|
| Ratchet teeth | 3 mm single-flute polished carbide, sharp uncoated edge, air blast | Coated metal cutters are rejected because edge radius smears PTFE-filled acetal. |
| Spring detent pockets | 2 mm PCD ball nose, shallow raster | A drill-point pocket would create a notch that traps the spring tip. |
| Central hub bore | 8 mm polished carbide boring bar after helical roughing | A reamer can bell-mouth soft polymer if chips pack. |
| Dowel holes | Carbide brad-point drill and light hand-free chamfer toolpath | Twist drill breakout is rejected for exit fuzz. |
| Outer indexing relief | 4 mm O-flute finisher | Protects tooth pitch while removing support tabs. |
Process order that prevents tooth deflection
Machine the hub and dowel pattern first while the blank is round and well supported, leave tooth stock until the bore is stable, then finish ratchet teeth in light climb passes. Detent pockets are finished before final outside release so spring force will land on a clean radius instead of a drilled notch.
Delrin AF chip, burr and heat control
Delrin AF tolerates speed but dislikes heat trapped by dull edges. Polished carbide and PCD are chosen for shearing, while coated steel-style cutters are rejected when their edge prep pushes material. Chip control uses air blast and open flutes, not flood coolant that hides fuzz.
Indexing and edge inspection
Inspection measures tooth pitch, hub runout, dowel relationship and pocket depth; visual checks look for white stress marks at tooth roots. A test pin indexes across several teeth to prove burr removal did not change functional timing.
Star wheel tooling FAQ
Why use uncoated polished carbide on Delrin AF teeth?
The sharp polished edge shears PTFE-filled acetal instead of smearing it.
Can the hub bore be reamed?
Only if chips are fully cleared; fine boring gives better control in a soft polymer hub.
What inspection catches tooth burr problems?
A test pin indexing through several teeth plus magnified root inspection.
