Physics questions

[ebscreen]

Some things I stay awake at night wondering, hopefully you guys can help.


Why has every vacuum lid exposure unit I've ever used always static shocked me
upon retrieving the screen after exposure?


On automatic presses with adjustable squeegee height and air pressure, are the two
adjustments interchangeable? IE can you lower the height of the blade and reduce the
air pressure for the same effect? Is 10 lbs of pressure on a half inch lift the same as 20 lbs on an inch lift?
(I'm sure it's not linear like that but you get the point) Would this explain how people print with vastly different
pressures?

[squeezee]

1. it could be your shoes, it could be your flooring, it could be the humidity in the room.  The neoprene rubber mat may store charge.

2. no

[alan802]

I treat squeegee distance travel and printhead pressure as different aspects and simply raise and lower the sq when adjusting angle and have it far enough down to make the mesh come in contact with the shirt.  You can use printhead air pressure all you want but if the sq isn't far enough down, all the pressure in the world isn't going to clear the ink so they do work hand in hand with one another.  And I also don't like pushing the sq down farther to simply add print pressure, you can have it down as far as you want but if you don't have enough printhead pressure, it's not going to print.  I use them in tandem to get what I want from a print and it's been great putting ink on top of the shirt instead of in it.

[ebscreen]

Thanks for the info guys.

For the static shock thing, it's happened on every unit (natural rubber, neoprene, butyl) in every
location (concrete and wood floor) I've ever been in. Vacuum pulling rubber over metal frame slowly
or something.


As for the squeegee pressure thing, I have a working knowledge of the concept, I just can't wrap
my brain around the actual physics. Weird stuff.

[Sbrem]

When you go to retrieve the screen, instead of approaching it gently, slap it medium hard. You won't feel the discharge because you're delivering greater force. Same with catching and getting zapped, I just give a quick slap to the dryer frame to discharge the static...

Steve

[screenxpress]

For the static shock thing, it's happened on every unit (natural rubber, neoprene, butyl) in every
location (concrete and wood floor) I've ever been in. Vacuum pulling rubber over metal frame slowly
or something.

Simple.  It's your magnetic personality.   

[ebscreen]

Haha, I was waiting for that.


I already smack frames, in and out of the exposure unit.
But that's another story.

[JBLUE]

When you go to retrieve the screen, instead of approaching it gently, slap it medium hard. You won't feel the discharge because you're delivering greater force. Same with catching and getting zapped, I just give a quick slap to the dryer frame to discharge the static...

Steve

LOL. I do the same thing. The wife thought I was crazy when she saw me buring screens the other day.

[Screened Gear]

Use a fabric softener sheet.

[Gilligan]

1. it could be your shoes, it could be your flooring, it could be the humidity in the room.  The neoprene rubber mat may store charge.

Or actually lack their of... humidity helps discharge static electricity.

[squeezee]

Try putting an earth strap on your unit - from the area where the screen goes.

[Im-Magic]

The air going into the Vacuum Blanket is causing it to gain electrons similar to a Van De Graaf Generator, hence the static charge and kick when you touch it. I agee that an eathing strap will solve the problem.

[mooseman]

True story many years ago, about 40+ now that I think aboiut it..... I had a somewhat frugal buddie who needed new carpet in his livingroom.
Being the tight fisted sort that he was he purchased a wall to wall carpet that was about 110%  nylon...I mean it was better than nylon and you guessed it major league static electric problem but hell he saved a ton of $$$$$.
It was so bad (and he was soooooooooo tight fisted) that he carried with him a piece of copper electrical wire bent and twisted into a loop kinda with the insulation on the handle part and about an inch or so of bare wire extending out beyond the loop.
He would use this gizmo to be the first part of him that touched things like lamps and such to "earth" the static charge he carried from that nice red rug.

Make  yourself a similar device, hang it on your exposure  unit and use it to be the first part of you that touches the metal frame, kinda like your own personal earthing device.
It is the jump across the gap so to speak that stings you when static charge is discharged.

 

[244]

Dry humidity,ozone and heat generating bulb,polyester mesh,and vacuum all add up to static. At the trade shows we keep a large coin like a quarter or euro in our pocket and use that to touch the machines before our hands do. Sometimes we see 1" sparks jump across the gap before we touch the product. Give it a try.

[mk162]

I know, I got an 1" long spark on the nipple one time when I was unloading shirts.  Not fun.