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Erkopress 300 Tp/Tp-ci™ |
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TECHNICAL NOTES
What equipment is used to create 3/10 mm (.3mm) thin copings?
The ERKOPRESS 300 Tp/Tp-ci pressure forming unit sold by Glidewell Direct. (item # 170000)
What material is used?
The ERKODUR 5/10 mm (.5mm) disc sold by Glidewell Direct (item # 521105). After pressing, the coping will be a uniform thickness of 3/10 mm (.3mm).
Do thermoformed copings fit the same as wax copings?
No, thermoformed copings fit better than wax copings. To achieve the correct expansion, we use 100% investment liquid (no water). This powder/liquid mix produces great results.
What instrument is used to trim excess material from the margins?
An electric wax pen with a modified tip (sharp blade).
What is the approximate temperature on the electric wax pen?
The ideal temperature setting will be determined by trial and adjustments. The blade needs to be hot enough to easily cut through the plastic material without actually burning it.
I´m having trouble getting the copings off the die. What should I do?
It is important to look for any over-extended margins. Since you are working with a plastic material, it only takes a small overhang to catch the margin. Using a semi-hard utility wax (white utility wax available from Zahn or Henry Schein) fitted in a small glass container will help pull the coping off the dies.
Do I trim my dies the same as before?
Yes, ditch the dies as usual. However please make sure the ditched areas of your dies are smooth and clean. This well-defined edge will enable the electric wax pen hot sharp tip to cut smoothly through the plastic and produce good-fitting margins.
Does this technique require any special Block out?
Proper block out is very important for two reasons. First, as the thermoform plastic is hard after it cools, it will engage any undercut and grab it firmly. Second, in this situation, if you manage to get the plastic coping off the die, there will not be enough metal to grind off to make any corrections after it has been cast. Because the metal coping is at 3/10 mm (.3mm), any attempt to reduce it to “make it fit” will ruin the coping—there is no room for errors. The proper block out is critical with this technique.
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