Cracks in the investment

[NathanNever]

Can someone explain the origin of these cracks. Occurred after a while I put the cylinder in the press furnace. I understood because I heard a tac. New packaging Speed ​​Press vest, two times at two times that I feel a tac and I have a slight crack. With the test kit provided by the rep did not happen. All according to instructions. Maybe I'm a bit slow in putting the ingot and Alox plunger, the investment retract, press on the plunger, and the cracks start?

 

[paulg100]

you make sure the plunger was completely clean?

If you use one with left over crap on it, it will split the ring like that as its forced into the ring.

 

[NathanNever]

Very clean, with a separator. The cracks do not appear to affect the work ..... I hope ......

 

[paulg100]

no they dont effect the work.

i get em now and again, dont cause any problems for me yet.

edit: i have the ep3000 with crack detection/pressure sensor though! if you dont have those functions may be more of an issue.

 

[NathanNever]

Thanks paulg100, now beginning to open ... oh yeah!

 

[NathanNever]

all right. I also have a ep3000. Are outputs with a layer of reaction is not just thin, above all 'inside of the crown. I do not like much, but I do not know what to do.

 

[paulg100]

when you next press a ring, drop the press temp by 2 degrees, then on the next ring 2 again untill you get fuzzy margins. that is your low temp cut off.

bump up 2c then that should give you minimal reaction layer with sharp margins.

edit: think im at 906 at the minute (it will be different for each furnace)/ Once you have it dialled in just use same programme for all ingots.

 

[NathanNever]

How do I change the software pre-installed?

 

[paulg100]

you can choose between factory programmes and custom ones.

read the manual man

 

[NathanNever]

You're right! I thought in the individual could not adjust E, and instead I can ... Ooops ... I had never entered into individual ...

 

[saleh zakut]

from E-MAX Product Information : After cooling to room temperature (approximately 60 minutes),the investment ring
may show cracks.
These cracks developed during cooling (immediately around the Alox plunger),as a
result of the different CTE of the various materials (Alox plunger, investment material
and pressed materials). They do not compromise the press results.

 

[user name]

from E-MAX Product Information : After cooling to room temperature (approximately 60 minutes),the investment ring
may show cracks.
These cracks developed during cooling (immediately around the Alox plunger),as a
result of the different CTE of the various materials (Alox plunger, investment material
and pressed materials). They do not compromise the press results.

Thats completely correct. If your getting an actual crack during the press, double check that your leveling cap is completely seated as soon as you fill the ring. You dont want the ring setting even a little ****-eyed during the press process.

 

[KentPWalton]

I hope you're scrapping the bottom of the rings before putting them into the ovens. And I don't mean using a model trimmer. Too much vibration and risk. I have a wet trimmer blade on top of a desk we hand scrap with on EVERY ring! This levels them off for proper pressing and allows gasses to escape.

 

[NathanNever]

Gases? but the pressed is in vacuum.

 

[KentPWalton]

Yes...the investment releases gases as it goes from a liquid state to a solid. Lots of gas builds up inside the rings. Have you ever had one explode in the burnout furnace? You have to scrape the bottoms of the rings if you are doing the fast burnout method. You don't have to scrape the rings if you are doing an overnight burnout because the rings bench set for 1 hour and go into a cold oven.

 

[NathanNever]

Is it okay to use a piece of sandpaper on a plan to keep it parallel?

 

[KentPWalton]

You can use anything you want. As long as you scrape the bottom to level the ring up and let gases escape.

 

[NathanNever]

Thanks Kent. I always used only the leveling cup.

 

[KentPWalton]

Have you had a ring explode in the furnace? Plus, don't use a watered model trimmer. The water actually reseals the ring.

 

[NathanNever]

No. Cracks have appeared a few seconds after entering and closed with the EP3000 press program. I heard a tick after about 20 seconds.