SORMZ Impression difference between units

Hi All,
We were doing print test of a SORMZ. When we did the solid breakaway test, there was huge difference between two units.
I have attached the pics for the reference.
We tested on 100 gsm Art Coated paper. Unit 1 solid ground was achieved at 0.1 mm on impression setting gauge, while same paper and same blanket on unit 2 achieved near solid ground at 0.3 setting on impression gauge.
In unit 1 if we move the impression gauge to 0.15 or above, there is no impression at all.
Yellow is unit 2 and Black is unit 1.
Can you please comment on what can be wrong that is causing so much difference between 2 units.

 

hey aqazi,
have you put a packing gauge on all the cylinders to verify that you are printing at correct height? Are blankets new? The most accurate print test results will come from blankets that are all, pretty close to the same age, and packing verified with a packing gauge as opposed to what the undercut tag lists. Ive seen variations when packing to the numbers on the tag. Especially on an older press where the cylinders may have caved in a bit. Once you've determined that both units have good blankets printing at the correct height, and that the plates are printing at the correct height, then try the test again but instead of yellow ink use something more visible. If you don't have a packing gauge then I strongly suggest you buy one. I usually try not to plug any products on this site but for affordability and great design I like the Baldwin packing gauge.

 

Thanks for your input turbotom . I interchanged the blankets to rule out any difference because of blankets but the result was same.
What mechanical issues can be with the press if let's suppose the blankets and packings are correct ?

 

Is there a dial that you turn, to adjust impression pressure that is out of sync? -e.g. dial gauge say 0 but actual thickness is 0.2-

 

Its a SORMZ, and there is an indicator for setting impressions one on each side, DS and OS.
How can I determine that it's a impression gauge fault or something else?

 

I don't know how accurate those dials that take a U wrench to adjust will be after years of use, but they can be used for a reference point at least.

If you've already made sure that the bare cylinder is free of rust and corrosion, probably the best way to check cylinder cut is to simply use a packing gauge. That won't tell you if the cylinder is even all the way around - although it probably is, but it will tell you for sure how much packing you need. With the press on impression, you could also use a feeler gauge to tell you what's going on with the distance between the impression cylinder bearers and the blanket cylinder bearers.

 

Looks and and sounds like your first move would be to check bearer pressures, Asif. You mention print test, if this is pre purchase assessment, the checking/setting procedures are a bit involved. You could start with blanket / impression pressure check, whereas on impression, there should be .35mm gap between impression and blanket bearer. Good luck!

 

@ Junker and Alibryan, 0.35 gap at impression settings on 0 and then machine on impression to check ?
This machine is in production and visually in immaculate condition and looks like it was refurbished fully.
The suspicious part is that the owner imported this press just 2 months ago for his own print house and now he is selling it at very cheap price.
So I'm a little sceptic about this.

 

I don't know anything about the .35mm setting. I do know that like with any press, you pack the plate and blanket cylinders for consistent pressure and the impression cylinder pressure you adjust for paper thickness. The one thing about a SORMZ is that with those dials on either side, not only can you adjust impression but you can also adjust plate to blanket pressure as well. However I don't know why you would want to do that unless you were packed to run off of the bearers and wanted some wiggle room for the type of blankets you were running. In any case, you need to be sure that those dials are set to zero as well, and that they're accurate.

There's a few things you could try so that you're able to troubleshoot what's going on with the press. It could be something minor that's fixable by adjusting your pressures, or it could be something major that's mechanical inside the side panel. Whatever it is, without a satisfactory breakaway test, I wouldn't suggest purchasing the press if you're planning on producing high quality work.

 

Yes, clean blanket bearers and impression undercut thoroughly, manually put unit on impression and and with long .35mm feeler strips, determine where dials are positioned when you have an even, strong pull on both sides. I believe it was in the late '80s Heidelberg did away with the plate /blanket adjustments, but if you have those be sure they are zeroed if you run another test. If you were running good blankets during this test, it appears there may be cylinder damage, easy to prove if it was the blanket causing the poor breakaway by flipping blanket and seeing if the problem moved.

 

How is the squeeze between blanket and plate? Try putting impression on without water rollers for solid and see if you have a uniform transfer to rule out the plate packing and check the impression jackets thickness -if there is one that is-

 

It's year 89 press with only one gauge for impression setting for blanket to impression cylinder .