Chris, I did some research on your furnace and it looks very interesting.
But one thing I'm worried about is that the plunger is air driven, very much like a hammer on the plunger's ring. Isn't it a bit risky ending up in cracked molds?
Ivo's is electronic with stop sensor.
Thanks
Thanks for the question. No hammers here, yes the plunger is air driven, but the speed and pressure are ring size dependent. Thus a 100g ring is more gentle than a 200g ring program or a 300g ring program. You must understand, the VARIO PRESS 300 and VARIO PRESS 300.e both have intelligent pressing systems that allow for the adjustment of pressure, speed and intelligent time as well as regular press time. Furthermore, the VARIO PRESS 300.e has the patented Advanced Press feature that can press lithium disilicate much faster than any other oven!
I am sure Patrick and others will agree, These ovens do not crack rings. In fact even some of the less intelligent ovens are not the culprit of cracked rings. Most (99%) ring cracking occurs due to a lack of consistent investing procedure or protocol, wherein the ring develops micro cracks due to improper handling. These micro cracks are then accentuated by the pressing oven. If you look at your rings as they exit the burnout oven and you see small cracks anywhere on the ring, then you need to revisit your investing procedure, because you are either not mixing fast enough, bench setting long enough or otherwise not allowing for moisture to escape the ring prior to putting it in the burnout oven. The moisture inside the ring that rushes to escape when placed in the burnout oven is one of the most common causes of cracked rings. That and misuses of debubblizer that causes finnning and Vaseline happy technicians that get Vaseline all over the ring former's.
1. Bench Set - I see it with Brand X's investment all the time because they have such a long bench set. No one has patience enough to wait 45 minutes. Instead they opt for the minimum time which is actually only meant for optimal situations. As soon as you wait the extra 10 minutes, cracked rings become a thing a the past.
2. Mixing speed - If you look at your mixer and you cant control the mixing speed (RPM),get a new mixer. It's that important. The faster you mix, the hotter the investment gets during bench set. The slower you mix the longer you need to bench set, but some investments do not like being to cold going into a hot oven soooooo...better know how fast you are mixing. This will also help you when the weather changes.
3. Vaseline and debubblizer...stop it..right now! Take your time and pour you rings carefully, then buy some new ring-formers because the Vaseline has probably worked its way into the ring by now. Having a hard time removing the rings without Vaseline? You might be surprised how easy it is with fresh ring-formers. If you insist on using debubblizer then from time to time you will get fining, deal with it. I would say always make sure its dried well, but that's a subjective statement. People tell me they blow it off with compressed air, but if you have noticed that's not a great answer because most of the time your compressed airlines have moisture in them! That is why CAD/CAM machines have to have serious air dryers on the lines....anyone that has bought a spindle knows what I mean.
Hope this information is helpful. Let me know if you have nay other questions.