water leak

[Josue]

I receive a used mold that ran PC/ABS,,, the last company use oil MTC, at 100 ~ 120C,,, We only have a water MTC,,,
the technician replace orings , but the mold has some water leaks and only disapear until the mold reach the 100C,,, so technician think this happend becasue the mold should run with oil,,, whats your opinion?, leak have a relation to use oil or water?,,, if we use oil we will reduce the posibility to have a leak?
we use high temperature oring.

Thks.

[Sustainability]

I receive a used mold that ran PC/ABS,,, the last company use oil MTC, at 100 ~ 120C,,, We only have a water MTC,,,
the technician replace orings , but the mold has some water leaks and only disapear until the mold reach the 100C,,, so technician think this happend becasue the mold should run with oil,,, whats your opinion?, leak have a relation to use oil or water?,,, if we use oil we will reduce the posibility to have a leak?
we use high temperature oring.

Thks.

Hello Josue,

The water becomes vapor at 100C [Boiling point of water], if your mold requires 100C+ mold temperature, I will not be using water as a heating medium. Ddi you check the water level after running it for few hours, definitely it might have gone down. Again, the viscosity of water and oil is different at 100C, so there is good chance you may not see any water leak.

Thank you

[brentb]

Oil has a greater viscosity than water (in general). If the hot water is under pressure, it can be heated past it's boiling point (100°F)
How high is your TCU rated?
What kind of coolant lines are you using?
For HOT (oil or water), one should use braided stainless Steel Teflon lined hoses with what we used to call JIC type flared fittings fittings.
There are hot water TCU units rated to 215°C with water. Single from Germany is one.

Be safe and KOM
brent

PS TCU and MTC are synonymous

[jnewmanco1]

Wittmann makes some that can go up to 325° F with water. I switched out all molds from oil to the water at a previous employer and was very glad to have done so. Much easier, cleaner, and safer when plumbed and used properly. If there is a catastrophic leak, as long as someone's skin is not right up against the leak, all they can expect to get is a warm dampening. We put shields up between our units and the outside people that might be walking around.

You can also use negative pressure unit like a LogicSeal and still run your water without leaks if real repair is not currently possible or economically feasable.

[brentb]

Logic Seal as a last resort for me, but then never tried on a hot mold!

KOM

brent

[rickbatey]

I've used negative pressure units with hot mold, it worked but I don't like to use them.
As far as hot oil goes, the new synthetic oils without the loose carbon particles are GREAT compared to that old stinky stuff! While at RAD, we converted a mold from electric heat (it took 12 hours to reach operating temp!) to hot oil on the next facelift mold. With new Conair hot oil units, braided Teflon hoses, and special high heat couplings that had to have the sleeves aligned to unlock, HUGE improvement compared to the old ones. You might need to replace those mold fittings to stop the water leaks. Could be worn or damaged due to heat stress.
Rick.

[Josue]

thanks for the advices,,, we use temp controller from matsui, and this models use water and are capable to run at 120C,, I now this temp should be steam, but use water and we dont see any steam ,,, the problem that we have its a small leak at the cavity like tears,, but ones that the tool get over 100c stop the leaking,,, I have a nother cuestion, if a tool ran at 90C with oil , and we set 90C with water, could this affect to the part dimensions?
I think oil has a stable heat or less lost of heat etc... but I never had this experience,have you experience this ?, basically should not affect, however this lost or not stable hit could be a "big" difference?,, so far I already try and didnt found any significative diference but inial running was only like 80 shots,,,thank you

[brentb]

Really should be measuring steel temp and not medium temp!!!!
Match steel temp!!!!!

KOM

brent!!!!!