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screen printing => Equipment => Topic started by: ericheartsu on March 08, 2013, 02:48:43 PM
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Our little gauntlet is having issues clearing a dark gray ink, through a 272 screen. I'ts a really blocky design, almost banner link, but it's not laying down enough ink on a single or even a double stroke.
We started with a tripple duro squeegee, switched to a smiling jack, and are now trying a 70 duro.
Any ideas as to what could be going on? pressure seems pretty constant
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My first consideration would be to lower the mesh. Dending on the image a 160 should do it.
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If the mesh isn't the problem, see if you can put enough pressure on the head to bend the squeegee
over. Bad cylinders can look strange sometimes.
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Yeah the leaky cylinder will cause those problems and I don't know how to determine a leaky M&R cylinder but on ours you can put your finger on the top of the chopper assembly during the print stroke and if you feel air coming out of the top air hole then you've got a leaky cylinder. After checking that I would definitely go to a lower mesh count. Are you trying to print WOW and need to print the gray through a high mesh count?
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just got back from lunch, and will try the air cylinders now.
Using a higher mesh, for a super soft print. It's just a one color print
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more flood pressure.
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Reduce grey, lower mesh, adjust pressure, profit.
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First look at the squeegee and see if it is bending when the choppers put pressure on it. You want to see it have equal pressure. If one of them has gone out it should have uneven pressure when printing.
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After no luck, we switched a different head, and it worked perfectly.
So this leads me to believe it's time to order some new cylinders!
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After no luck, we switched a different head, and it worked perfectly.
So this leads me to believe it's time to order some new cylinders!
Eric!
I assume it is an older Gauntlet. If is is change the print cylinders to 1" bore instead of the original
3/4" cylinders. Flood cylinders can remain 3/4". I might have some layin around my shop. You got
my numba!
winston
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After no luck, we switched a different head, and it worked perfectly.
So this leads me to believe it's time to order some new cylinders!
Eric!
I assume it is an older Gauntlet. If is is change the print cylinders to 1" bore instead of the original
3/4" cylinders. Flood cylinders can remain 3/4". I might have some layin around my shop. You got
my numba!
winston
I did the same thing as what Winston said here. Huge difference. We run 3/4 on the flood and 1in for the squeegees. Well worth the investment.
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Before you replace the cylinders check the MAC valve(s) first. Call M&R service for the procedure to troubleshoot the cylinders/mac valves
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Those cylinders aren't rebuildable? I know the newer presses have rebuildable cylinders.
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I'm guessing it's the older style head with two linear bearings, and the cast head--they have slots in the sides of the heads for bars that brace the squeegee and floodbar holders front to back, and have the height adjustment on top with a lock on the side. The rather small cylinders are inside the head. The newer style is like a cartridge--a box with a height adjustment barrel on top, quick connects on a side, and a shaft out the bottom that threads onto a yoke for the holders. Much nicer, for sure.
Might be worth double checking your guys are keeping those channels clean and well greased too--if you run them dry they'll wear the head, and height adjustments get a little weird if it gets a lot of play in it.
I could only assume going 3/4 to 1" on the choppers would be huge--when I ran a GT-8, we were always slowing down the stroke because we couldn't get enough pressure against the ink/screen. I still miss having single/double and front/back on switches though. The E100 is a little tedious like that.
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Anybody know the largest bore that will fit on a '92 GT-6?
We have 3/4" installed (0.80" o.d.).
I know that 7/8" will fit.
But will the 1 1/16" get in there?
It looks close by my caliper measurements.
A lot, like practically all our print choppers are weak as hell (yes, also checked the Mac valves and going to replace at least one) so I'm going to retrofit all new and want the most muscle I can fit in there.
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i think I would run 1" in mine. You should be fine with that, and put small ones on the flood, there isn't a need for a ton of flood pressure.
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It looked like the 1 1/16" would fit but I wasn't sure. Have to order a couple and see.
Are any of these rebuildable? I see SMC and Bimba make ones that will work in both sizes. Or maybe it's not worth it to rebuild?
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nope, not rebuildable.
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nope, not rebuildable.
That seems silly. What is that makes them go? Prolly a $0.75 o ring.
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uhh are you sure they can't be rebuilt? we are rebuilding the air switches at the moment. super small o rings inside, they leak a bit and make the air locks really weak. I need to upgrade our bimbas too, mainly in head 1 and 6 for whites. I think 1" is the way to go zoo...
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I think 1" is the way to go zoo...
Damn right it is...if they fit. I'll post up if they do or not.
I wouldn't mess with trying a rebuild on 'em unless they were made specifically to be rebuildable.
We're 2x stroking color 1 on a 2co DC run right now b/c only one of our heads has full pressure, all the other cylinders are weak so I'm seeing the importance of this. DC takes a little muscle even on an auto press. No complaints though, beats knocking all this out on the manny, which is tied up anyways...
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Like Homer said it's usually the first and last head with this issue. You can put a drop of pneumatic oil
in the air inlet to see if it helps, and verifies this is the problem. On other machines I've seen sticky
air valves create similar issues (typically not getting full pressure until the end of the stroke).
Rebuildable air cylinders are $$. It's a sealed vessel with some pretty hefty forces going on....
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1" will fit fine. I run 1" on the squeegees and 3/4" on the floods. 3/4 just cannot handle the pressure. It was the first thing I changed within days of getting the press.
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Yup, not rebuildable. like eb said, the ones that are get pricey.
I preferred the Clippard brand, but they were 7/8th inch bore.
I am going to check around Aero's site for a single action cylinder for the RPM.
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Like Homer said it's usually the first and last head with this issue. You can put a drop of pneumatic oil
in the air inlet to see if it helps, and verifies this is the problem. On other machines I've seen sticky
air valves create similar issues (typically not getting full pressure until the end of the stroke).
Rebuildable air cylinders are $$. It's a sealed vessel with some pretty hefty forces going on....
The shop I started at has the same model same year press, when we moved it (nearly ten years ago now,) I went through the whole mac bank and pulled the top hose, put a drop of oil in, replaced it. That machine went over two million impressions a couple years ago, and they still haven't replaced any of the cylinders or valves. Don't get me wrong, most of them could sure use it, but the thing is still banging out prints.
Of course, you've already checked your oiler, right? ;)
Homer: Never thought about pulling apart an air switch--I have a few that are getting hissy, might have to check that out. Thanks for the hint.
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1 1/16" will fit on these presses. It increases pressure twice as much as a 3/4'' cylinder.
Force = Power Factor x Pressure
To keep it simple ex. 100psi
3/4" -Power Factor .44
1 1/16" " " .88
So a 3/4 at 100psi= 44psi, 11/16" at 100psi = 88psi
Quite a difference!
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Of course, you've already checked your oiler, right?
1 drop every 7/8 cycles with everything on... I think I read that right in the ol' manual? I'm new to using metric crap tons of air in machines. Air supply appears to be bone dry so far, nothing to drain from the FLR.
That's cool Winston, makes a lot of sense to think about it that way. Glad to hear the big ones fit, I had ordered just a pair to check.
Now I wonder if you can upgrade the stroke/flood cylinders too? They appear to struggle with getting the stroke going and up to speed and staying smooth and consistent across that whopping 15-16" of travel.
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Of course, you've already checked your oiler, right?
1 drop every 7/8 cycles with everything on... I think I read that right in the ol' manual? I'm new to using metric crap tons of air in machines. Air supply appears to be bone dry so far, nothing to drain from the FLR.
That's cool Winston, makes a lot of sense to think about it that way. Glad to hear the big ones fit, I had ordered just a pair to check.
Now I wonder if you can upgrade the stroke/flood cylinders too? They appear to struggle with getting the stroke going and up to speed and staying smooth and consistent across that whopping 15-16" of travel.
we are in this boat too. they seem to struggle as soon as it starts printing, causing weird lines in alot of our prints
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Of course, you've already checked your oiler, right?
1 drop every 7/8 cycles with everything on... I think I read that right in the ol' manual? I'm new to using metric crap tons of air in machines. Air supply appears to be bone dry so far, nothing to drain from the FLR.
That's cool Winston, makes a lot of sense to think about it that way. Glad to hear the big ones fit, I had ordered just a pair to check.
Now I wonder if you can upgrade the stroke/flood cylinders too? They appear to struggle with getting the stroke going and up to speed and staying smooth and consistent across that whopping 15-16" of travel.
we are in this boat too. they seem to struggle as soon as it starts printing, causing weird lines in alot of our prints
Yeah the chatter at print start is kinda silly, you could place the top of the image lower but at some point you have what, a 12x15" print area? So far all we're running is DC on it and it's just fine (freaking great actually and saving our butts in here right now) but we haven't ran anything bigger than 6x9 or so and won't have to until next week I don't think.
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we were getting that in our new machine, the lines are the flood bar stuttering along the stroke. for us -it was insufficiant air volume. Maybe check your air lines for a kink /leak? Check the valves too, maybe it's a little dirty or possibly sticking. If it does it on every head then you may need more air....The old gauntlets sip air, they don't need much at all. What type of set up do you guys have? We had to run a 3/4" line to a 30 gallon captive air tank along with a 56 cfm chiller from our 80 gal tank. but this is to run both gauntlets, the gauntlet 2 gulps air, I can watch the tank drain about 5 PSI with every index. the 6 color gauntlet can run on a bike pump compared to that thing....I need to find a rotory screw asap.
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We are running a 7.5hp with a 10gallon tank through a matched compressor. We have a back up tank connected to that, and we run our 6/8 gauntlet, our 10/12 xpress, our svecia, and roller master all through it. the xpress and svecia don't have any issues with the stuttering...but we do need a new oiler on our press, maybe it's just running dry
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Adjust the oiler to approx 1 drop of oil per every 7-8 revolutions.(critical)
Homers right on the airlines! Crank up your air pressure as high as it will go to the regulator. Adjust
between 105-115 at the regulator. don't forget to adjust flow control valves on the bottom.
Also Drain all the sludge from the bottom air tank. (press frame) . Cut the air, unloosen the plug,
and blow it out. Get all kinks or replace air lines as needed. Grainger has it 5/32",1/4". The cool
thing on these old gauntlets, is that you can retrofit and "trick" the heck out of them. You can increase
stroke cylinders also. When the presses were designed 16 newtons was tight. The Looser the screen
the higher off contact. If you use higher tension frames, drop your off contact. Make sure squeegee rubber
is FLAT... Round corners so edges don't turn down. Sufficent air pressure is critical on all air presses. They can
fly if you treat um right!
winston
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For us, also 7.5 horse screw/chiller/tank, 3/4" line. Prob not an air supply issue for us at least, surprised how little the compressor kicks on actually. The rods on our stroke cylinders feel very well lubed to me and I think the oiler is running fine from watching it when I set it, if anything it may have been over oiling. Our flood seems fine but the stroke "chatter" is more like the stroke cylinder starts pulling and the blade hangs out and can't move (at some speeds) or comes slowly and then speeds up, like it's caught on the squeegee edge and can't break the surface tension. Probably just the nature of air heads but I could see where a stronger stroke cylinder might be the missing link. I mean, if you beef up the choppers but the stroke cyl can't pull them consistently at that pressure, well what's the point?
On the valves I was kind of thinking I should've just bought a brand new mac valve bank for this thing instead of the two single 45a's I have coming. It would eliminate a lot for trouble shooting.
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Drain all the sludge from the bottom air tank. (press frame)
Brilliant idea, def going to do that. I have all this wonderfully clean, dry, perfectly lubed air running into a tank full of god knows what.
So you can increase those stroke cylinders then? Looks like there's some serious room for upgrading there, what do you recommend?
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1/4" or so . Don't go crazy unless you have larger compressor. (critical)
Do little things! They really add up.
good luck.