CET Flatbed Neg. Pressure issues

[cwb143]

Don't know if anyone has posted this problem but I have a problem with negative pressure fluctuating too high and low. Sometimes while the printing is going it will drop to 2.8 and drop ink on material. So I'm wondering if there is a fix for this?

and on another note
This is the most manual machine I think I've ever ran there is nothing automated and that equals more chances for error and slowness. Ill never understand why they put vacuum zone controls in the back of a printer either.

 

[artbot]

does it seem to drop in the same spot? or same set of spots?

get to the controller and have the carriage go slowly across the gantry. see if you see any fluctuations in the negative pressure. have a piece of scrap on the table and make a mark if and where it does. if going back and forth with the gantry produces predictable points of negative pressure drops, then you have an air leak that is probably within the cable guide and that guide is arching the air tube at that point allowing air to escape.

as for CETs. very simple machine to work on. but i had lots of trouble with the used one i purchased.

 

[cwb143]

does it seem to drop in the same spot? or same set of spots?

get to the controller and have the carriage go slowly across the gantry. see if you see any fluctuations in the negative pressure. have a piece of scrap on the table and make a mark if and where it does. if going back and forth with the gantry produces predictable points of negative pressure drops, then you have an air leak that is probably within the cable guide and that guide is arching the air tube at that point allowing air to escape.

as for CETs. very simple machine to work on. but i had lots of trouble with the used one i purchased.

THanks but I don't think that will help me as when I come into the shop first thing in the morning is when I see the pressure all over the place and ink leaked out in the waste tray. Any ideas what is causing it to be unstable while not running?

 

[artbot]

i'm assuming that the printer/air pump is left on overnight. if the air pump is fluctuating here and there, the air pump is going out. i replaced the one on our fk with an original part $110. company is in the US. don't remember the specifics but you can read the info right on the pump. also there are many generic air pumps on ebay and such that should be able to replace for very little money.

also what model is this? the km512's on the fk had a tendency to get get a little loose at the ink inlet and would then sweat ink and let air in at the base causing negative pressure issues.

 

[synergy_jim]

sounds like a bad pump.

 

[StarSign]

I don't know much about the CET but my Arizona was having a similar problem we replaced the degasers and filters, fixed the problem.

 

[Tom Dalton]

Here, I posted a survey to find out what brand of UV printer is impressing its users. Please rate your CET here..
http://www.signs101.com/forums/showt...ot-UV-flatbeds

 

[cwb143]

Thanks Art! I'll check it out. last two days its been doing better and yes it's left on overnight. The model is the xpress 500. Dosn't appear to have any leaks in the lines. But for some reason its doing better as of lately.

 

[davecich]

Neg pressure issue

Call our office in the am and ask for Barry. When the seasons change, the manometer needs to be zeroed out. He will explain how. We are also creating a series on YouTube in which we have videos for the most common maintenance issues.

Dave Cich

ps- if you don't get satisfaction, call 404-915-7524. It is my cell.

 

[cwb143]

Thanks Dave will do. Also do any of you know why the printer prints everything in 180°? My preview shows the art in the correction position.
but when I print it out its rotated 180°. Is it just my printer or is that a know issue?

 

[artbot]

that drives me nuts. i think it's from the firmware being originally written for a belt feed printer and you would feed the print head first into the stops. well the person then gets on the other
side of the printer and the thing comes out head first (aka up side down). a person operating a flatbed sees the table, stands at the table and has a "south to north" relationship with the printer.
prints should print "bottom first".

we ended up making a huge error on a super expensive install without CET because it was so difficult to relate to the orientation. a gradient was upside down on a panel. some in the graphics department "pre-rotating" the images 180. others depending on the rip which is set to rotate. others un-pre-rotating. in the end, no one wants their print to appear on the table upside down.

 

[cwb143]

Awe man I feel your pain. No one should have to think too long whether or not the graphic is in the right position.

 

[davecich]

follow up and 180 degree

Sir,

I just want make sure your negative pressure issue is resolved. It is usually the monometer is dirty.

Also, Onyx was built originally for a roll printer. If you go into your default screen you can change it permanently.

Dave

 

[Matt-Tastic]

Thanks Dave will do. Also do any of you know why the printer prints everything in 180°? My preview shows the art in the correction position.
but when I print it out its rotated 180°. Is it just my printer or is that a know issue?

OK, I know this is a month old, but I wanted to chime in (also, i've been away from S101, sad days)

The print does not print "upside down". I assume you are printing from ONYX, which shows you the preview from top to bottom. the printer prints from the top point to the bottom of the image. Since it starts at the top, it seems to print "upside down", but honestly you're looking at it from the wrong side.

it's a matter of perspective, as we've been rotating images for trade shows to print "upside down" in the RIP for years, just so they hang on printers correctly when coming out.

 

[cwb143]

The negative pressure has been resolved. CET came out and did a wonderful job and fixed a lot of issues. But they couldn't fix the rotated image issue. You can rotate an image anyway you want in onyx and it will look the same on the preview at the CET monitor. But what prints out is 180° opposite no matter what you do. Since the CET monitor is in front of me. and the vacuum switch is in front of me thats the side I need the image to print where I can read or view right side up. The reason for that is cause we do alot of double sided printing and it would be easier to manage flipping sheets over and checking art positions. or if we're printing multiple sizes on a template that require special placement without having think about it upside down would be great! I know everything looks wonderful at a tradeshow printing one offs of Pamela Anderson but in the real world it just doesn't work like that. And I'm amazed at how many companies start off on the wrong foot with new printers without ever considering what others have done before them. Products could be so much better if they just study history and talk to operators in the field but I could say the same thing for software developers.

 

[CWolf]

Same issue

What was the solution for this. Im having the exact same issue only it seems to happen when we are not at work. Ill come in in the morning and will have lost all my inks. This has happened to me twice now. We have already replaced the main pump, printer is left on to mist overnight per CET instructions.

 

[Nameci]

First is close all your ink supply valves, remove the negative pressure regulator and blow air to clean it. If the negative pressure regulator is dusty, moisture accumulates over time and restricts air flow thru the throttle causing the negative pressure to increase. If after cleaning the negative pressure regulator the issue still exists, might be the right time to replace the negative pressure regulator. Another possible cause is a bad pump or overflowed ink on the ink overflow tank.

 

[lexcorp]

Former CET field technician here to help

I am glad your negative pressure issue got fixed. As far as the image goes and printing double sided prints. Using your margins and header in the CET software ensures accurate placement of the image no matter what the orientation on the screen.

For more information
Ryan Persad
470.216.4451
Persad2605@gmail.com