Ivoclar Vivadent IPS e.max ZirPress - Manual (Page 21)

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Sprueing
Always attach the sprues in the direction of flow of the ceramic and at the thickest part of the wax-up so that smooth
flowing of the viscous ceramic during pressing is enabled. Depending on the number and size of objects to be invested,
either the 100 g, 200 g, or 300 g IPS Investment Ring System is selected. Bridges must only be pressed in the 200 g or
300 g IPS Investment Ring System. Before sprueing, weigh the ring base and record the weight (seal the opening of the
ring base with wax).
We recommend the following procedure to determine the
accurate wax weight:
– Weigh the IPS ring base (seal the opening of the ring base
with wax)
– Position the objects to be pressed on the ring base and
attach them with wax. Weigh again.
– The wax weight is calculated by deducting the weight of
the ring base and the weight of the ZirCAD framework
from the total weight.
– Use the respective number of ingots for the calculated wax
weight.
1 ingot 2 ingots 3 ingots 6 ingots
Wax Weight max. 0.7 g max. 1.7 g max. 2.2 g max. 5.1 g
Investment Ring System 100 g, 200 g 100 g, 200 g 300 g 300 g
The following sprueing guidelines must be observed:
– Observe a distance of at least 10 mm between the wax-up objects and silicone ring.
– The maximum length (wax objects + sprue) of 16 mm (100 g, 200 g) or 20 mm (300 g) must not be exceeded.
– If only one object is invested, a second short (blind) sprue must be placed. This ensures that the switch-off function of
the furnace works properly at the end of the pressing procdure.
– If the 100 g IPS Investment Ring System is used, a somewhat steeper sprueing angle to the ring base must be observed.
– In bridges, provide at least one sprue for each bridge element.
– In large crowns and/or bridge units (e.g. molars) 2 sprues should be provided (see”Sprueing of long-span bridges”).