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Heat Press Settings: How is pressure related to temperature and time?

Heat Press Settings: How is pressure related to temperature and time?

Heat Press Settings: How is pressure related to temperature and time?

(OP)
This is my first post and I am a newly graduated EIT, so please bear with me. I need to know how pressure
is related to pressure and time.
I only have equations that relate heat conduction to area, temperature, and time; furthermore,
I don't remember any such relationship in my heat transfer or thermo courses.

Background:

I work for a textile/garment manufacturer. The laborers in the plant use the heat press
to create neck seals and wrist seals for dry suits. Our newer heat presses have a pneumatic release
feature and the pressure is set digitally, but our older presses still use manual release and manual
pressure settings.

Problem:

The female employees in the plant have trouble using the manual release heat presses; it is simply too
hard for them to lift the handle that lifts the upper plate. My initial though was to simply lower the
pressure setting; this seems to solve the problem for the users, but I am wondering how to compensate for
the change in pressure by changing the time or temperature settings, or if I even need to. Why or why not?


Thank-you very much in advance, any help would be appreciated

RE: Heat Press Settings: How is pressure related to temperature and time?

There may not be a comparable setting. 350F for 10 minutes is not equivalent 3500F for 1 minute.

Presumably, your process is already optimized for a set time, given the maximum temperature the materials can tolerate. Running the temperature higher could potentially burn the material. Since time is money, there may be great reluctance to increase the time. No one can give you any relationship between the three; it would be unique to your process, equipment, and materials.

Have you looked at possibly augmenting the release mechanisms so that less force is required, i.e., like making lever-arm longer?

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RE: Heat Press Settings: How is pressure related to temperature and time?

(OP)
Thank-you for your reply. An engineer before me already modified the lever-arm so that it is longer,
but it is not sufficient. The heat press process is optimized for temperature and time with the constraints
that you mentioned; additionally, there is a constraint that the bond tensile strength must exceed 35lbf.
I have seen the QA tests and there is room to play around with time and temperature, but they have been using this
manual setting for pressure for quite sometime. I didn't want to do any DOE to test the settings but I guess there
is no other way. Do you know of any resources that discuss material bonding physics for engineers?

RE: Heat Press Settings: How is pressure related to temperature and time?

To echo IRStuff's comment (and expand on it) If you increase either the time or the temperature you run the chance of burning or melting the fabric rather than sealing it. (I'm thinking back to the days when I worked at my dad's dry cleaners and pressed clothes -- it was a fine balance between pressure, temperature and time.)

A simple solution may be getting them a mat to stand on so they are a bit taller (presuming they are standing).

I also suggest looking at the design of the machine. If the lever arm has already been lengthened, then maybe it needs to be oiled to reduce the amount of effort it takes to move it? Can you take a picture of the lever arm or that side of the machine? Maybe it would be easy to modify, but I don't know.

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RE: Heat Press Settings: How is pressure related to temperature and time?

From what little I know about rubber, I don't think that the pressure really has much to do with it.

There is "enough" to keep things from squirting out as they expand.

Less than "enough" and you don't make a good part.

"Enough" or greater is fine.

RE: Heat Press Settings: How is pressure related to temperature and time?

Instead of women operating the older presses, hire men. Case in point, one of our clients perhaps two decades had women performing certain tasks around injection molded parts and the problem was that the women hands would fatigue "prematurely" during their workshifts. The solution was that our client hired male Hispanics to do similar tasks and the problem was solved. The reasons were simple, these Hispanic men, in general, were stronger than the women and had the additional benefit of having small hands that were needed to do the tasks. By contrast American "Anglos" have larger hands than Hispanic males and large hands were not suitable for the tasks.

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