Improving the system/reducing downtime

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Re: Improving the system/reducing downtime

Postby Gory » Sat Mar 02, 2019 12:36 pm

P1- We a lot of damaged aniloxes. Mostly vertical cuts and bumps that appear with every anilox rotation -
I am reading this to mean they are across rather than along the anilox, this is usually caused by bumping them during handling, the ceramic chips quite easily. Lines that run along the web, ie go all the way around the circumference are generally caused by abrasive particles in the ink getting trapped behind the blade.

P2- Some aniloxes are blocked therefore ink transfer rate is reduced. We have a laser cleaning machine but they say it damages aniloxes so it can only be used once every 6 months. Is this true?
there are a number of companies that specialize in anilox cleaning chemicals, get samples and try them between lazer cleanings.

P3- Operator has to visually check each plate to know which unit to place it in, knowing that each plate has the color written on it (Ex: Magenta plate has magenta written on it and the order file says magenta should be in unit 3 so operator places magenta in unit 3).
That's all I have ever seen

P4- Each doctor blade chamber has two tubes at the top of the chamber. When the return valve is clogged these tubes let out excess ink that is not returned to the bucket which causes the Ink to start spitting from those tubes at high velocity dirtying the machine and wasting ink.
do you have hoses to direct this into the splash pan under the chamber, if so do they actually lie in the pan?

P5- Doctor chamber explodes spilling ink all over the machine (Usually happens with highly viscous inks like white and gold)
not uncommon, unfortunately - some operators like to run ink pumps very fast, if the ink is going in faster than it can come out (or be consumed) it will find the weak point, build pressure there and blow. Not the only cause, but not uncommon. Time how long it takes for a gallon to come out of the chamber, then time how long it takes the pump to pump a gallon, go on from there.

P6- Operators dont know how to solve some of the problems. Through trial and error they keep wasting resources until the problem is solved without knowing what the defect and the root cause of the problem are
Do you have an experienced manager? Do you have any of the troubleshooting guides most ink vendors can provide you with one.

P7- Sometimes we have to stop production because a line of ink appears between each bag and the other (We call it joint but i dont know what the term is). Usually happens after cleaning
As said earlier - that is a picture of plate lift - also, hard to be sure but it looks like too much impression on the blues on those images, I see a 'halo' around the print - operators will often over-impress to compensate for weak ink strength/ worn or plugged aniloxes.

Good luck, have fun, keep us updated
Gory
 
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Re: Improving the system/reducing downtime

Postby Flexforlife » Sun Mar 03, 2019 4:57 pm

longtimefan wrote:This is one type..

What type of pumps or ink delivery do you use?



Checked with my boss he says we already have the filter but not of high quality like the picture you posted
Flexforlife
 
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Re: Improving the system/reducing downtime

Postby longtimefan » Sun Mar 03, 2019 7:39 pm

Flexforlife wrote:
longtimefan wrote:This is one type..

What type of pumps or ink delivery do you use?



Checked with my boss he says we already have the filter but not of high quality like the picture you posted

Get them.. They have magnets and will help
longtimefan
 
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Re: Improving the system/reducing downtime

Postby guy de cafmeyer » Mon Mar 04, 2019 4:14 am

Aniloxes ; These can only be damaged if mechanically damaged , Press problem ex) rollers don't lift when stopping and idling , or blades are being wound on to make up for a poor wipe .
I bought ceramic aniloxes about 10 years ago , and they are still going strong . One was damaged by the operator dropping something onto it , otherwise no problems . They are ultrasonically cleaned every two months , or where it is evident that a density is too low ( process set ).
Upon printing , one should start from a standard ; colour sequence same , aniloxes same , densities of process set same , and viscos the same . If your repro house is worth their salt , then only minor adjustments need to be made . Only once in a while should the operator be required to deviate from standard set-up . All jobs should have a history folder of the passed-off sample , with basic details ; sequence , aniloxes , visco's , progressive of each process colour , and the signed sample .Notes if a "fiddle" was needed . . .
Plates can be scribed with an N/T cutter ex) M for Magenta etc
Inks; if something is clogged , it means that it was not cleaned ? Also , one can place a filter on pumps nowadays , which is advisable . .
Explosion of ink ; One should have a valve on the ink pump that one can control the rate of flow . The doctor blade ends should leak very slightly , as it is the lubricant to prevent extreme wear of the end seals . These should be looked at continuously , and changed once the drip become excessive .
Ink Lines ; this is simply the plates lifting off the sticky back . This is common , but one can ; buy plates of softer shore ( limpness of the plate ) hardness , stick plate edges down with sticky tape , cut the plate edges at a bevel , use a more adhesive sticky back etc . Older plates tend to lift after time as their use does result in the hardening of the plate ..
Pics that you have posted have two defects ; the one has excessive impression , but too little inker . the other one is exactly the opposite :). The bad cupping on the edges is also visible , and this is a combination of stick back hardness vs plate durometer . ( Most common is plates of high durometer with softer tape , softer plates with harder tape .)
guy de cafmeyer
 
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Re: Improving the system/reducing downtime

Postby TexMaintMan » Wed Mar 27, 2019 7:08 pm

Wow... you have a lot going on. Let's start with your aniloxes.. Do you practice press side cleaning? In the media cleaner.. Are you using the correct media? Damaged aniloxes with score lines.. Are the blades set properly?

Plates.. Your plate department can add a line on the plate along one edge to determine which plate it is.
Doctor Blades.. should have 3 ports. Ink in the center port, return lines on either side. If the pump is set too high it will blow out the end seals.
TexMaintMan
 
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