TSB

screen printing => Equipment => Topic started by: sweetts on March 25, 2012, 09:48:55 PM

Title: dwell time on dryer
Post by: sweetts on March 25, 2012, 09:48:55 PM
I have a harco ultra cure I was wondering how to adjust the time or temperature the heaters kick on and off. Like right now I have it set for 345 my heater stays on till it hits 365 and then wont kick on till it at like 325. There has to be an adjustment right?
Title: Re: dwell time on dryer
Post by: tpitman on March 26, 2012, 06:13:01 AM
I think every electric dryer operates pretty much the same. The panels are either on or off, and the temperature control attempts to average it out to the temperature you've specified, unless there's a control out there that operates more like the dimmer on a light bulb.
This is probably where a gas dryer shines.
Title: Re: dwell time on dryer
Post by: Printficient on March 26, 2012, 08:23:38 AM
Give Winston a call.  904-343-0848
Title: Re: dwell time on dryer
Post by: ebscreen on March 26, 2012, 02:27:43 PM
Is it a digital controller? If so, then yes there should be an adjustment for the over/under shoot or "swing" as they call it.
Analog (mercury switches) should have an adjustment for that as well, though I'm not familiar with it.

Two things. First is that setting too fine of a window (IE within a degree or even less) can have your panels
switching on and off several times a minute, if not every second. Not good for your relays or wiring or panels
even.

Second is that most digital controllers (PIDs) have a "auto-tune" or "learning" program. These are bad ass.
You set your parameters, and the controller learns the characteristics of what it is controlling. IE my dryer
is set to 425F, the controller (after learning for awhile) knows to throttle back the burner at about 415 or so,
so that it doesn't overshoot the set temp too much. Same for kicking back on. Keeps the dryer to within 2 degrees
or so of the set temp constantly.

Title: Re: dwell time on dryer
Post by: ScreenFoo on March 26, 2012, 03:17:49 PM
For the record, finally popped a mercury relay a couple years ago, after several decades of full time use, and it cycles about every ten seconds.  Seems like it's pretty consistent for temp, although with really thin stuff you can see the temp jump and drop with the cycling, even when it's cycling that often.

There's probably a trimmer on the control board for how close it tries to match the thermocouple to the control--or how fast it cycles, if there isn't a thermocouple.  Docs are hard to come by for that junk...
Title: Re: dwell time on dryer
Post by: Sbrem on March 26, 2012, 03:28:10 PM
You may also have a Percentage Input Timer,  but I've never seen one with a temp controller. We have one old dryer in which the controls were such a mess that in the end it's on full tilt, and we adjust with the best speed. Not very scientific, but it works fine and dandy. Digital controllers are indeed the way to go though, as mentioned above.

Steve
Title: Re: dwell time on dryer
Post by: sweetts on March 26, 2012, 05:52:29 PM
I will play some mire and let You guys know,,, it is a digital controler so I must have overlooked the adjustment

Sent  from samsung gem(the worst smart phone ever)
Title: Re: dwell time on dryer
Post by: ebscreen on March 26, 2012, 06:16:09 PM
Manual for the dryer likely won't have it. Look up the manual for the digital controller.
They can be a funky set of keystrokes.
Title: Re: Re: dwell time on dryer
Post by: sweetts on March 27, 2012, 09:20:04 AM
Manual for the dryer likely won't have it. Look up the manual for the digital controller.
They can be a funky set of keystrokes.
Will do I never thought of that Thanks! !!

Sent  from samsung gem(the worst smart phone ever)
Title: Re: dwell time on dryer
Post by: RICK STEFANICK on March 28, 2012, 08:59:57 PM
I would call mike over at brown.
Title: Re: Re: dwell time on dryer
Post by: sweetts on April 18, 2012, 03:10:13 PM
Give Winston a call.  904-343-0848
Hey Thanks for giving me Winston's contact info, what a nice guy  he was very helpful

Sent  from samsung gem(the worst smart phone ever)
Title: Re: dwell time on dryer
Post by: sweetts on April 25, 2012, 02:59:15 PM
Just a follow up I contacted the folks that make the controller, they sent a free manual and learned What all those functions do. LOl the dry is now acting like it should thanks for the assistance O0

Sent  from samsung gem(the worst smart phone ever)