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screen printing => General Screen Printing => Topic started by: ZooCity on April 09, 2015, 05:41:31 PM
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Circling back around to something brought up in a post a few weeks back - plastisol flash times with quartz units. Our flash times seem abnormally long. I want to figure out why and, more so, ensure that we are using our quartz flash correctly with this ink.
Today there's a perfect example on press, a PFP white base through a 150. It's PFP/revolve due to order size and the fact that it's underbasing fluoro green plastisol which always gets 2 underbases. 12.5" x 11" image, maybe about 60% solid fill area. Here's the exact spec on the base and it's flashing:
Sportsman EX
Wilflex Epic Quick White, no additives.
150/48 S @ 26 n/cm coated 2/1 round/dull edge - 55/90/55 blade - 1stroke @ 45psi - 4.5 speed - 15˚ angle - 5/32" or 0.16" off contact from platen
Platens @≈115˚F
Red Chili 2024 @ 2.75" from platen to bulb. Leveled. All zones on. Power:75 Time:10s
Seems long on the flash right?
We also get an issue on occasion where there's a wavy pattern in top colors going over a white plasti base. I'm convinced it's flash related at the base. Of course it came up on this run; a big fill area of plasti fluoro on the hilite will reveal every tiny thing that is wrong with a base. So I had my dude up the intensity, drop the time and try everything in between. We aim for "just flashed" so that the ink film is a little tacky feeling but we cannot lift off ink with finger pressure. The settings above were optimal for the print....
So what is the "right" way to flash plasti with quartz and when do these 0.5s flash times I hear about come into play? Quartz flashing is probably a non-issue for most of you all, but it's time for me to go to school on this.
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it sounds like you are using a really low mesh count for the underbase.
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holy ch1t 10 sec on a quartz flash is like forever.
for comparison... we have a 2024 RedChili-D ... we use the 'temperature' feature and the flash at 100% always, even on triblends...
for quick white, we have the temperature set at 200 degrees... first flash is probably around 10 seconds or so, after the flash warms up just a bit we're between 4-6 seconds for a standard gildan shirt... This is to full flash, none to very little tack... After platens are hot, we're down around 2.5-3 sec.
Bulbs are at the recommended height, right around 2.25" if I remember correctly.. (not at the shop so I can't run back and measure).
this is with a 160S same coating... just about the same print specs otherwise... even with a 110S, we've never had flash times over 6 seconds.
-J
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Hey,
Just because I have been playing with this lately, let me see if I can help.
Jvanick - are you allowing the flashy I turn on and off in between prints or leaving it on continuously.
Does the flash have an idle circuit where you can leave the bulbs at a lower power between prints?
What is your cycle time?
With these answers we can probably connect why one is so different from the other
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Hey,
Just because I have been playing with this lately, let me see if I can help.
Jvanick - are you allowing the flashy I turn on and off in between prints or leaving it on continuously.
Does the flash have an idle circuit where you can leave the bulbs at a lower power between prints?
What is your cycle time?
With these answers we can probably connect why one is so different from the other
the flash is definitely turning on and off.
there's no idle mode on the flash.
index dwell is at 5.5 seconds.
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Zoo city
What is your cycle or index dwell?
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Zoo city
What is your cycle or index dwell?
I'll check with the printer who ran this tomorrow. We don't record dwell times usually.
This might be why our time seems long, I believe my crew is currently using the eye/sensor on the chili so the flash kicks on as the platen indexes beneath it in the table down position, remains on as it tables up and strokes/dwells and, possibly, as it tables back down. It would depend on the dwell as you said but it could make our "10 second flash time" effectively more like a few seconds of actual table up flashing with the other seconds really providing much less intensity in the table down position. I'll look into it tomorrow, thanks!
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Zoo here is one more thought
1.
Jvanick's speed is very good and consistant, as he stated the first flash is close to 10 seconds. This is because everything is cold. The bulbs have to use some of there energy to heat there surroundings.
2. After running it quickly becomes, 4-6 seconds. The surrounding items (the bulbs, metal, pallets so
On) are already hot.
3. Once everything has been running the flash time is even faster.
4. In this case due to a consistant pace the flash rarely turns off and only for seconds.
Zoo city
1. Is running in revolver mode, on cycle one a shirt is being loaded only.
2. Cycle 2 a no shirts are being loaded or unloaded
3. Cycle 3 a shirt is being loaded and unloaded (much slower)
4. This is a very inconsistet and the flash is turning off for much longer times. In this case the surrounding areas absorb the energy again pushing the flash back to 10 seconds.
Solution be it the wrong way to do it or not...
1. Print faster, be more consistant (I know this isn't always a option)
Or
2. Print at comfortable pace, using a idle circuit. Keep the flash at about 20% as to keep the surroundings warm but not enough energy to burn a shirt (yes not as efficient as on and off but more consistant) I am not sure if this can be done on this specific unit or not. If not heat your boards up for 10 minutes before starting any testing, most likely will be enough to lower flash times, but with two rounds this might still not work perfectly.
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I agree with jvanick, our times are fairly similar but a touch quicker it seems. We are almost never over 5 sec on flash time. When we are running 200+ pcs orders I would say 90% of the time we are at 2.5 sec or less... I've know of shops that had bad main power fead to their shop causing stuff like flashes to not run to full power but to the eye looked in good working order. Might take a look there if you haven't already.
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We have all the same equipment. I ran a 500 piece 7 color job on it today with quick white underbase and had flash time at 2.5 sec to start. Pallets were warmed up first. At 50 shirts, flash was at 1.8 sec. At 100 shirts, the flash was at 1.1 sec. We ran at 66 dz an hour and had that job done in less than 40 mins. We always use 100% power. Never any less. We never run a flash on a run for over 3.5 secs and that is only if the pallets have cooled between switching screens, but that time only for the first 2 revolutions, and then never over 2.2 sec. We do use a press cable and not the sensor.
Our typical underbase is on a 135/48s
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Chris:
The wavy pattern you see when you print flash print your underbase and then throw a top color on is a form of Moire. The pattern presents itself when the peaks and valleys of the double base print (what ever has been p/f/p) interfere with the other peaks and valleys printed after.
If you change the mesh counts for the double base plate: 150 base 180 second white - then top color through what you want. The pattern will disappear.
The pattern is most evident in inks that are more translucent than others. Opaque colors hide the effect really well.
I guess my question about flash times is based on shirt type and weight, how dry are the shirts, how long are you flashing when the platen is in the up position/what is your index speed (as was asked earlier), and how thick of a base white are you printing?
Myself: we use SF2 cotton and low bleed. We print through the same mesh counts as you and lay down a verrry nice deposit. As a direct result I can rarely bring my flash down below 3 seconds. If the coverage area is big it stays up around 5 seconds. This is all counted when the platen is in the up position. We typically run at a 4 dwell, sometimes 4.5 if we have a large area of coverage. 14 color Sportsman EXG. I forgot which quartz flash....
When we print a second white in sequence and we need to flash it, we are usually at 2-3 seconds when the boards are at production temp. That is typically high 120's - low 130's.
I have had orders with a mix of shirts where we had to change the flash times for each brand/type of shirt. Some had excess moisture, some had a high poly content and flashed QUICK, some were just thin while others were very heavy. All that can change your flash parameters....
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Great thoughts Steve but not the cause in our case unfortunately. Flash times are very similar on a revolve or regular one trip around. Also, I have the crew trained well on preheating. Both the platens and the flash unit are warm and stay that way the entire run. With the flash not firing you can feel the built up heat coming out of the unit and, as I mentioned platens were at 115deg at start. But I agree, pace is important with flashing.
I don't want to get hung up on the revolve example. Revolving a base is ultra rare here, only for very small orders, this one is 36 pcs with 3 types of garments, and only for situations like neons where the base needs to be an ultra smooth work of utter perfection for the transparent top ink to look good. Normally this would be two UBs in sequence for a single revolution and the ub screens would typically be different mesh counts.
Danny, we must think alike as I already barked up that tree. Flash was installed on a 30a circ initially I did a calc on the fla again when we moved and bumped everything up to a 40a circ. Didn't make a notable difference.
I am really interested in checking the actual table up dwell, it could well be we're only flashing in table up for a handful of seconds. Also going to play with height to a degree. JW and jvanick, the direct comparisons are very helpful in examining this.
Rich, if you think a 150s is too open a mesh for a UB, think again! JW here is taking the "Alan approach" it seems- ultra open mesh count with fast clean strokes. The 135 is as close as I've seen to just printing through open air, that mesh dumps ink. We don't print plasti with a 135 s but it is the champion of HSA around here. In the right hands, you can do incredible things with any ink with a mesh that open. Anyone using these meshes right will have ink just completely on top of the garment so while it may look like we're all pounding too much ink into the shirts, it's actually not the case with thin thread mesh used properly.
Colin, that was our initial suspicion when it came up on other jobs in the past so we typically run alternating mesh counts. Regular plasti tends to have a 180 S base, 225 S top colors or the like. This is just a special case of needing serious deposit. Coincidentally we have a very similar job with identical inks going up soon so I'll try swapping the base or hilite mesh and see if that resolves it. Makes perfect sense that revolving the base would just enhance the moire effect.
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Zoo-
was hoping for the simple answer, here is another thought
Power:
Switching from a 30a breaker to a 40a breaker is not where the power issue is.
Where the power issues is:
1. The lines feeding the unit are two small. In this case they would get very warm during use.
Or
2. Let's say you are hooked up to 208 3phase. If you put a meter on the unit while it's turning on check the incoming line voltage. In many cases it will read 198v which will make the unit run much colder. in instances even lower than that. The lower that number is the colder the unit will run.
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Steve hit upon an issue that brought my company to it's knees. 208 vs 240 caused us very long flash times with infrared or quartz. We were in the 15 sec on infared, and 10-12 on quartz. We found that adding an additional flash if you have a head available helped keep pallet temps to 190 using a ray gun thermometer. We focused on pallet temps to get faster flash times but struggled with 208v for a year before getting 440v installed stepped down to 240. Cut electrical bills by 1/2 since 440 is far cheaper than 110 which is used in 2/3? lines to make 208v.
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we run tacanna and cayenne, both flash at 1.5 to 2.5 sometimes less.
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we're on 208v service here.. (actually hovers around 200 or so)... no problems with long flash times...
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in the control panel, are you setting the flash dwell under the Flash time or the Quartz time.
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We're 230v 3ph, high leg delta service here. I can confirm there are no voltage issues with the flash as I was just in there with the meter testing after the power surge we had last month. Steve, when I said I upped the circuit I meant the whole circuit was upgraded, not just a breaker swap. That's a crazy story Alan, I can't imagine dealing with that in a larger plant. 190 sounds real hot to run platens at, even as a last resort to comp for the flash times. Was that a long time ago? I hear you can't get a 440v service in my area anymore.
Someone mentioned humidity, it was about 70˚ and 24% humidity yesterday but weather is manic in our environment and can change many times throughout a day or a print run.
Investigated the dwell and how much time the flash was actually on in the up position. We're at about 5-6s in actual tabled up flashing for a job like I described. The rest of the time the flash is on the table is indexing or lifting/lowering. We're going to start using the PLC hookup and use the Quartz Flash settings to get better control of this.
So with these figures on flash time, what are you all setting the preheat and delay at?
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We're going to start using the PLC hookup and use the Quartz Flash settings to get better control of this.
So with these figures on flash time, what are you all setting the preheat and delay at?
Yeah, get the PLC!
I just figured you had it with a quartz.. ???
preheat at 7 seconds and you can adjust the time in the control panel with quartz time.
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That's a crazy story Alan, I can't imagine dealing with that in a larger plant. 190 sounds real hot to run platens at, even as a last resort to comp for the flash times. Was that a long time ago? I hear you can't get a 440v service in my area anymore.
Everything was a long time ago for me! I wish we had some of the newer flashes of today back then. My quartz were custom built flashes for an MHM SA 14/12, a tank of a press that maybe hit 400pcs per hour on a good day! All on or off and no sensors, just a dwell. We ran hot pallet temps to lower the dwell, but also had to use fans to balance the temp. Today's base plate inks also fuse a little sooner than ours did back then, hence high pallet temps with pallets that had no rubber covering. Plus we were running 110 with a thick ink deposit and needed the hot pallets.
Did get a free years rent due to 208v since I specified to realtor 240v which he claimed the building had! Still I never got 208v production to run as fast as 240v. About 2/3 the output.
Al
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Hey Zoo,
Thanks for the explanations back. Being new to the board, I am jumping into things without knowing the levels of expertise on this board. I hope some of my simple concepts will help the newer guys.
Couple more questions, a little more technical if you haven't found a solution yet.
What is wattage of each bulb?
What is the color temperature?
Are these bulbs third party of factory?
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Hey Zoo,
Thanks for the explanations back. Being new to the board, I am jumping into things without knowing the levels of expertise on this board. I hope some of my simple concepts will help the newer guys.
Couple more questions, a little more technical if you haven't found a solution yet.
What is wattage of each bulb?
What is the color temperature?
Are these bulbs third party of factory?
Sure thing Steve, I appreciate any and all input and it never hurts to double check things that you think you have on lock.
This is an M&R Red Chili, they may be able to answer the questions you have. My guess is all quartz bulbs are made by a third party and some manufacturers may have their own propriety ones made for them but heck, you would know that being a manufacturer. Sorry, I'm just not overly interested int he color temp/wattage/bulb make as I'm able to do easy, direct comparisons with others with this unit since it is so widely used.