Specifying Inlay Bushings: ID, OD & Length Selection Guide
Key Takeaway: Select bushing ID to match tip insert OD (H7/h6 fit), OD to match plate bore (H7/p6 press-fit), and length = insertion depth + 2–3 mm margin. The inlay bushing protects the plate bore from repeated tip changes and provides precision guidance for the insert.
Dimension Selection Table
| Parameter | Determined By | Fit Type | Tolerance |
|---|---|---|---|
| Bushing ID | Tip insert OD | H7/h6 (close clearance) | Insert slides in by hand |
| Bushing OD | Plate bore diameter | H7/p6 (interference) | Press-fit into plate |
| Bushing length | Insertion depth + 2–3 mm | — | Must not protrude past plate |
| Bushing material | Application hardness | — | SKH51 standard; STAVAX for corrosive |
Why Bushings Are Essential
Without a bushing, repeated tip insert changes wear the plate bore directly. After 10–20 insert changes, the bore enlarges beyond tolerance, causing tip misalignment and part dimensional issues. The bushing absorbs this wear — it is far cheaper to replace a bushing than to re-bore a mold plate.
- Bore protection: Bushing protects the plate bore from repeated insert/remove cycles
- Precision guidance: Hardened bushing bore (HRC 60+) provides consistent concentricity over thousands of tip changes
- Independent replacement: Bushing can be replaced when worn without modifying the plate
Installation Procedure
- Step 1: Verify plate bore diameter is within H7 tolerance
- Step 2: Cool the bushing (freezer for 30 min) or heat the plate locally to ease press-fit
- Step 3: Press bushing into plate bore using an arbor press — ensure flush with plate surface
- Step 4: Verify bushing ID with bore gauge after installation (pressing may reduce ID slightly)
- Step 5: Insert inlay tip into bushing — should slide in smoothly with no force
Frequently Asked Questions
How do I select the correct inlay bushing ID?+
Match the tip insert OD with H7/h6 fit. The insert should slide in by hand with minimal clearance for concentricity.
What determines the inlay bushing OD?+
The plate bore diameter. The bushing is press-fit (H7/p6 interference) into the existing bore. Standard metric sizes available.
How long should the inlay bushing be?+
Insertion depth + 2–3 mm margin. Must guide the tip across its full working length without protruding past the plate surface.
Related
Need Inlay Bushings?
Specify plate bore diameter, tip insert OD, and insertion depth — we'll recommend the correct bushing specification.
✓ Standard sizes in stock✓ Custom lengths available✓ MOQ 1 piece