Integrally heated, flow-through design bushings: Elite series SV and LV bushings can process commodity and engineering-grade resins.
Close-pitch mini-manifold systems: Precision series bushings with internal flow and external heat are suitable for processing temperature-sensitive resins.
Heated spine bushings, nozzles, manifold blocks, and pre-assembled hot-runner systems.
In these cases, metal saturates the refractory lining between the loop and the bushing. The above prediction methods don't detect this saturation because the effect of the buildup masks the effect of the saturation.
However, when the bushing contains an uncooled joint that incorporates a transite T-bar for the electrical isolation, the thermal gradient in the bushing joint area is adversely altered.
In this method, the bushing is fitted with Type K thermocouples.
Certain applications demand special bushing designs, including longer lengths for greater accuracy allowing the bushing to butt up to the workpiece, thin-walls for use in high precision close hole patterns, and directed coolant bushings for drilling hardened steels that require cooler running drills.
Drill bushing characteristics that must be considered include length, inside and outside .diameters, head, and material.
Headed press fit (ANSI H) - Low cost bushing for use where high pressure, as may be caused by chip buildup between the spindle and the bushing, could force headless bushings through the jig plate.
Since neither the conductance ratio nor the reactance ratio enables the determination of how close the saturation network is to the bushing, a new measuring stick is required.
Using a simple clock diagram, the thermocouples are taped to the outside of the bushing at the 3, 6, 9 and 12 o'clock positions.