SUPER-FURNACE!!! (Sintering)

[CoolHandLuke]

2 hrs cycle time? you arent going to snap zirconias like twigs with this rapid cooling ?

 

[DMC]

I think I go from 900C high temp to ambient in under minutes in my porcelain oven with Zirconia. Right?

That's only to keep the porc from popping off. Zirconia can be cooled even faster than that.

So.....add more heat and time....

We are cooling in 30 minutes now from high temp. The Zirconia is not what slows me down, but rather my furnace. I don't want to destroy the insulation and elements from thermal shock.

Nothing is snapping.

Total time in furnace is just over 3 hrs, not 2hrs.

Did I really say Two hours somewhere in this thread? If so, that was wrong.

 

[jijimon]

What is the three buttons on the rightside used for...please explain

 

[DMC]

1) Vertical Take-Off

2) Self-Destruct Initiation

3) Self-Destruct Confirmation



Just kidding....
They operate a relay that energizes the transformer in bottom of furnace.
Used for safty. I cut power to elements only if I need to go up top and play with elements. Computer stays on. Meters still work. Elements are physically un-hooked from power. It's a big moving relay bar in a box.

 

[rkm rdt]

Amazing!

 

[CoolHandLuke]

so what youre saying is, you dont need to slow cool full contour zirconia... it has no porcelain, so it can go from full 1600 dec C to ambiet as fast as you can make it get there ?

and NOT break ?

 

[DMC]

Yeah, that's word for word exactly what I said.

As a matter of fact, why don't you throw your Zirconia into a bucket of water and quench at high temp.

Tell me how fast you cool Zirconia in a porc furnace.....

You still think 30 min. cool is too fast huh?

30 up
30 down
2hr hold.

 

[CoolHandLuke]

thats just my dillemma... my furnace for sintering currently is 2hrs to get to 1600 deg C, hold 2 hrs, natural cool to room (8 hrs)

but i see you with 3 hrs and i have to start wondering if im wasting 7 hrs.

 

[DMC]

You bought a new furnace from somewhere? right?

There is no way they would let you do this type of stuff, and provide some sort of warrenty on the equip. It's just too close to the edge!

What you see me doing is pushing everything to the limits! My furnace will need to be rebuilt much sooner than yours, as I will eventually crack the entire chamber into pieces! I will also be changing my elements more often. I will be breaking my trays more often and loosing my Moth-Balls all over the place.

BUT, there is hope!

I have found all these things cheap enough to outweigh the destruction and labor I face ahead and I gain the ability to accept files at 4:00 PM and even later (shhhhh) and still have to customer's lab next day.

 

[DMC]

thats just my dillemma... my furnace for sintering currently is 2hrs to get to 1600 deg C, hold 2 hrs, natural cool to room (8 hrs)

but i see you with 3 hrs and i have to start wondering if im wasting 7 hrs.

Open your furnace a little starting at 950C ( a few millimeters).....then at 750C a little more....then at 600C...then at 450C remove the tray!

We do this all the time! You will need to find a source for very very cheap trays, and beads.



We have a bucket of High-Temp Al-Cement. It has many good uses!

We re-glue our furnace back together. Same stuff they were made to begin with! I get from Zircar in NY.

This includes the door insulation. I try to keep furnaces very sealed.

It's exactly like making a Ginger-bread house with Iceing and foam blocks.

Smackle that crack, and seal her up! It fun and very cheap and easy.

Very dangerous to breathe the dust!

 

[DMC]

Your furnace walls and thermocouple with be reading 450C. It takes much longer to cool that, than your tray and the air inside the now craked chamber.

We use an Infra-Red thermometer with Laser pointer to confirm the tray is actually much cooler. So, the furnace is not actually reading the temp of the Zirconia and the tray.....convection with the open door gets those cooler faster. Did that make any sense?

 

[KMoft CDT]

Scott,
THANKS! for taking time to share so much in this thread and others. You're putting it all out there (Zr Balls and all!)
Too cool!!!
(gotta talk the owner into a Warp Drive for ourselves):flame::flame:

 

[KMoft CDT]

thats just my dillemma... my furnace for sintering currently is 2hrs to get to 1600 deg C, hold 2 hrs, natural cool to room (8 hrs)

but i see you with 3 hrs and i have to start wondering if im wasting 7 hrs.

Exactly!!!
I know I don't want to destroy the furnace... But I'm thinking...
I could get those trays out of the 1700B (GW) quicker, close the furnace back up and let it cool down on its own? (Maybe put the Zr trays under a Pyrex dish to slow the cooling a bit?)
What temp could I open it up?
s?

 

[KentPWalton]

That is a 15" tall 2 Liter bottle sir.

The furnace is over 5'6" tall and about 500lbs!

Not exactly a bench-top model.

It was scary as all hell trying to get the crate out of truck!


7000 watts of pure hell-fire at normal operation. A 20 amp/230V breaker won't work. I found that out already. Had to call the electrician for a little upgrade again.

Electricity is included in my Ten year agreement with Landlord. LOL

I didn't have any serious machines when I signed that. Now I bet I suck 2x my rent in electricity!! It's pretty funny too me.

Haha. Sucker born every day!

 

[Vazone]

You still think 30 min. cool is too fast huh?

30 up
30 down
2hr hold.

So you use 50 deg ramp for heating and cooling? that only for FCZ? or also use it for bridges?

i can set ramp to 70 deg/min

 

[e...w...h]

What's a good source for sintering trays? I'm having a hell of a time getting them from our vendor.

 

[DMC]

Sentrotech in the US, but they just order from China.

brofurnace.com or google?

I buy 20 at once. We are hard on the trays!

 

[e...w...h]

We have a prototype tray made from some top secret material that has lasted us weeks. Perfect. We do the 2 hr cycles and used to go through trays daily... they are cheap tho. Problem is... we only have one black tray

 

[e...w...h]

I'm in desperate need of 95mm diameter sintering trays! Anybody have some they can send over?