Board Expansion/Swelling while printing 300 GSM Board of size 28" x 40" - 5 Colour

[cooladi006]

Hi all,

I am looking out for a 5 Colour Offset with size - 28" x 40" of year 1990-1995 model.
I have been warned by a few that running a job in 28" x 40" size board will lead to board expansion/swelling and hence the print output would not have a good registeration.
Can anyone please clarify whether we ll actually have a registeration issue in printing due to board expansion/swelling ? If so, then what precautions are to be taken to ensure it does not happen and he print quality is maintained at its best.
Thanks.

Regards,
Aditya Jain,
Matrix Prints.

 

[Meny]

In 2 words - bull-****.
Yes , printing is not the absolute proccess , and paper may change on press due to water gain & pressure , but if this was the case..... no one would buy 40@ presses and surlly not bigger....

The problem may be on thin stock , but on 300 GSM it is nothing to worry about.
Any way , some presses have tricks to overcome fanout issues , but not as early as 1990 - 95.

Need advise ?

Good luck

 

[cooladi006]

There is a belief that paper slightly expands - may be slightly 0.5 mm in case of bigger sizes of sheet such as 28"x40" but would be safe of the sheet size is 23"x36".

Can I please know as to what kind of improvement in the machine would have taken place in the machines after 1995 which solves the issue of paper expansion/swelling so that I can take care of it while buying the 5 colour - 28"x40"

 

[Meny]

Newer Komori & KBA presses have the abillity to counter the fanout at the feed board
if you can not pay for it...simply comprmise , as this is the nature of print

 

[cooladi006]

Ok. I was just curious to know as to how do they counter the fanout.
I mean what is that particular feature which counters the fanout of the paper ?

 

[Meny]

log on to komori.com

You will find the full answers on komori web
site

 

[cooladi006]

Tried a lot looking through the website. Was not able to find out anything specific relating to solving the paper swelling/expansion issue.
Anyways thanks.
1 thing is clarified - printing 300 GSM Board with Sheet Size of 28" x 40" would not have any board expansion issue.
Only paper issue has to be sorted out.

 

[turbotom1052]

even the older Heidelberg presses offer a "compensator" on the ranger drum to make corrections for sheet fanout. The problem is that on many presses the compensator is not returned to its zero position after it is no longer needed and then it wears out and fails to work. This however can be fixed for relatively low cost.

 

[aqazi81]

@turbotom.... will you please explain, How that compensator helps in paper fanout? I have changed its setting many times but it has not made much difference.

 

[turbotom1052]

aqazi,
the compensator on a speedmaster puts a little bow in the center of the sheet as its in the ranger drum. If its not helping you ill bet its worn out. As mentioned above you must only use it when needed and return it to its zero position when not needed. If you continue to run over a long period of time when not needed it will wear and do nothing to help. Ive also found that it doesn't do much on board but when in good shape it helps on paper.

 

[aqazi81]

Ok...Thank you.