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moldingppm
2nd January 2014, 01:24 PM
Hello everyone.
I hope you all have had a good holiday and new years.

I have a 400 Ton HPM (1981 model I believe) that I'm having some issues with.
My normal startup for this machine goes as such;
1). Turn on machine power
2). Turn on barrel heats and pump, let sit for about an hour
3). Start production

Here's my problem. My oil temperature isn't rising by the time I start production. This causes the clamp to slam shut (if I have the forward slowdown at the setting that it was at when I shut it down). If I move the slowdown back, then I can get the mold to close nice and slow. Over a few hours, the machine starts to hit the slowdown point, and not reach final lockup (as if I have the slowdown set too far back).

I'd assume that this would be an issue with my oil temp? If I were to add a heater to my tank and start the machine with the oil at the same temperature (80*F +) every morning, would this stop that slamming and constant adjustment during production?

If this is an issue, does anyone have any ideas how I can heat my oil? I'd assume that I could rig a temperature controller with a t/c to heat the oil so that my oil is nice and warm on startup.


Thanks for your time.

Chris
2nd January 2014, 01:41 PM
ha ha, at first i was thinking mold heater when i saw the title.

How i am not fimiliar with an HPM, most machines have some kind of a valve at the water output to control the oil temp with. most of the time these are controlled through the controller or per-prgrammed from factory to keep the oil at a constant temp.

If you machine is not controlled by this method, you could always buy a controller, add a thermocouple in the oil tank, electronic ball valve to the out side of heat exchanger.


80 F is too cold for a injection molding machine, i like to run mine at 100-110.

Chris

moldingppm
2nd January 2014, 02:40 PM
I should have put a different title lol. But you're talking about the mechanical valve for the water cooling going to the exchanger. This wouldn't be a fix for my issue as keeping my oil cool is not the issue, I'm looking for a way to have the oil heated while idle. Being there is no load on it, the oil temp is barely moving.

Yes 100*F is more where I should be. My oil is around 65 when I'm starting the machine. See my dilemma?


ha ha, at first i was thinking mold heater when i saw the title.

How i am not fimiliar with an HPM, most machines have some kind of a valve at the water output to control the oil temp with. most of the time these are controlled through the controller or per-prgrammed from factory to keep the oil at a constant temp.

If you machine is not controlled by this method, you could always buy a controller, add a thermocouple in the oil tank, electronic ball valve to the out side of heat exchanger.


80 F is too cold for a injection molding machine, i like to run mine at 100-110.

Chris

moldingppm
2nd January 2014, 02:41 PM
I guess the correct term for what I'm looking to do is add an oil pre-heater

Chris
2nd January 2014, 03:26 PM
yes, cold oil will allow for a spongy clamp, actually when i came in today from the long holiday, my oil temp was 54F....the machine ran over an hour to get to 110, since then it has not come off of the setpoint, and my tower water is 60F

well with a controlled valve it will only let water through the heat exchanger when allowed..

therefore if the set point of the oil is at 110 and the actual temp is at 100 the valve would be shut, not allowing any water to pass through the exchanger, but if the actual temp got to 111 or higher, the valve would open, therefore cooling the machine down to 110 then closing.....this can go on and on and on.......

here is an exmple of the electronic ball valve
http://www.grainger.com/product/DYNAQUIP-CONTROLS-Electronic-Ball-Valve-1AWD9?s_pp=false

rickbatey
3rd January 2014, 02:42 AM
Even machines of that vintage normally had water saver valves on them to reduce the cooling water flow if oil temp was low. The diaphragm is gone, stuck open, or someone removed it years ago. I'd try to fix it but I don't think that's all your issue.
When a press sits, air rises to the top of the clamp and injection cylinders (mostly it separates out of the oil). Your issue is from the air being trapped in the cylinder. Your press may have a manual air bleeder or you can open and close it several times to flush the air out. Older Husky's had small manual valves you cracked open after closing mold, then you tried to build tonnage on it to flush. I also run the screw full stroke, both directions,before charging screw.
Also the cold oil is causing slow shifting of the valves. You need to make sure the preheat system works and if not repair it.
Rick.

brentb
3rd January 2014, 05:22 PM
Ditto for Toshiba, Rick and happy new year

moldingppm
3rd January 2014, 07:27 PM
I swore I replied to this earlier this morning. Anyway, the water saver, you're talking about the mechanical water valve that opens and closes water flow as the temp changes? The machine does have one, whether it works or not is the question.

Would the air have anything to do with the slamming? I've started the machine after working the clamp a few times in mold set as well as applied high pressure clamping, and still got slamming the first couple of shots.

Now, would the viscosity of the oil while it's colder (60*F) be different than at, say 110*F? I would assume so. So what I'm getting at is, if my oil we're at operating temperature (90-100*F) when I started my machine, would I have to make any adjustments if I shut it down at 100*F the day before? I know my question is a little tough to understand, I'm having a tough time conveying what I'm trying/need to do.

As far as the preheat system, that's exactly what I'm asking about. My machine has no preheater on it, so I'm trying to retrofit or add one to it to warm my oil before I start for the day. I'm sure having the machine sitting and idling for an hour or two will barely bump up the temperature as it's running with no load.



Even machines of that vintage normally had water saver valves on them to reduce the cooling water flow if oil temp was low. The diaphragm is gone, stuck open, or someone removed it years ago. I'd try to fix it but I don't think that's all your issue.
When a press sits, air rises to the top of the clamp and injection cylinders (mostly it separates out of the oil). Your issue is from the air being trapped in the cylinder. Your press may have a manual air bleeder or you can open and close it several times to flush the air out. Older Husky's had small manual valves you cracked open after closing mold, then you tried to build tonnage on it to flush. I also run the screw full stroke, both directions,before charging screw.
Also the cold oil is causing slow shifting of the valves. You need to make sure the preheat system works and if not repair it.
Rick.


Ditto for Toshiba, Rick and happy new year

Yep, my Shinwa Seiki's have the bleeders on them too. I'm not sure if this HPM does.

rickbatey
5th January 2014, 02:11 AM
No press I'm aware of has an oil heater; they just load the pump at say 30% and create heat by pumping the cold oil through a series of valves that are cracked open. Creating shear heat in the oil. Perhaps the valves or software parts are not working?
Cold oil in the ram cylinder can cause issues but it is sluggish valve reaction due to the thick oil if you've flushed the air out of the ram.
Yes the water saver valve is the bulb in the tank and a semi-mechanical valve to slow the water volume through the heat exchanger. It's more than likely stuck open. Close the tower supply valve next start up and see what happens.
Rick.

moldingppm
5th January 2014, 05:49 PM
My Shinwa Seiki's have an actual tank heater, all the others heat via pump load.
This machine has a BC Maco III-B controller on it, which I'm sure doesn't have any way of controlling oil temp, especially since someone retrofitted a temp controller on the machine to keep track of the temps.

I'll start the pump tomorrow and measure the temp with the tower on and then with the water on tuesday and see if I get any temperature changes. I will keep you posted. Thanks for all of your help!


No press I'm aware of has an oil heater; they just load the pump at say 30% and create heat by pumping the cold oil through a series of valves that are cracked open. Creating shear heat in the oil. Perhaps the valves or software parts are not working?
Cold oil in the ram cylinder can cause issues but it is sluggish valve reaction due to the thick oil if you've flushed the air out of the ram.
Yes the water saver valve is the bulb in the tank and a semi-mechanical valve to slow the water volume through the heat exchanger. It's more than likely stuck open. Close the tower supply valve next start up and see what happens.
Rick.