Roller replacement guidlines?

[tpeetros]

I'm trying to get some feedback from the folks in the industry on how often the rollers in a printing unit need to be replaced.

If I listen to the operators, they want new rubber every 8 months. We only buy Bottcher rollers for our 40" Komoris. I'm thinking that with proper care, we can pull the rollers, clean up the side frames and the journals on the rollers, replace the bearings, reset the rollers and be good to go. I'm guessing any standard would be based on number of impressions not time as that would vary depending on crewing and workload.

Any help would be appreciated.

 

[QualityPrint]

To find out your optimal replacement time use a durometer gauge to check the durometer when you are putting fresh rollers in. We use a 5 point increase on our ink rollers and a 7-10 point increase on our water rollers for a benchmark as to when they need to be replaced. This only has to be done a few times to establish an average for when to replace. Once that time is found you can set up a program.

I guess this all depends on how you want to characterize things. If you have very color critical clients and repeatability is a high priority you may want to tighten your tolerance. If you don't have color critical clients then you can probably get away with a little broader tolerance.

Replacing rollers is a costly venture and one must always keep that in mind when developing any type of maintenance program. For instance, 8 years ago we were running with ink rollers that increased 10- 15 points that were 3 years old. Stability was an issue though and we had to change to ensure repeatability. We are printing more repeatable now which helps greatly when matching proofs. I guess I don't have to tell you how the customers feel about that.

Hope this helps

 

[Lammy]

I'll second that. Durometer is the only way to be sure if they need replacing or not, aside from if they are totally falling apart ;-)

You should be able to contact your roller supplier and ask them what the rollers should be when they were shipped to you. Then you can check to see what your rollers are now.

You can also typically let your intermediate rollers go a longer (harder) than your forms.

 

[Cornishpastythighs]

Some print unit rollers may need to be changed more frequently due to the fact they are washed up much more than the other rollers. For instance 6 colour press printing 4 colour process in 4 units and spot colours in 2 units. Spot colours are changing for every job process colours are not. Spot colour units get hit with more solvent and will probably need to be replaced more often than the process rollers. Also roller life can depend on how they are set in the press, wash up procedures, type of ink (UV/Hybrid/Conventional) and type of solvent used for wash up (too aggressive). Just some thoughts for you.

 

[GazKL440]

Machinists = Often as possible to avoid fighting your press for good results.

Owner = often as possible to to ensure good returns.

This means once a year for operators, once a decade for owners.

As a machinist I see the diminishing returns that result from lengthy make readies, reprints and hair pulling for what they are: saving money NOW in new rollers = long term loss = false economy.

Unfortunately most* owners see the dollars flying out the door (let's face it a new deck of rollers for a big press ain't cheap... times 4, 6, 8 or more!!) and understandably baulk at splashing out on them

Middle ground would be when you reach that point where you look at a proof and think "hmmmmm going to need to tweak some rollers for this!".

Fair enough it would be great to live in a perfect world where replacing rollers on a reasonable schedule exists... but I guess given the struggle that the printing industry is facing simply to stay alive, that perfect world is shrinking rather quickly!

* not all owners are like this!

 

[CD102]

To find out your optimal replacement time use a durometer gauge to check the durometer when you are putting fresh rollers in. We use a 5 point increase on our ink rollers and a 7-10 point increase on our water rollers for a benchmark as to when they need to be replaced. This only has to be done a few times to establish an average for when to replace. Once that time is found you can set up a program.

Why have you set a wider tolerance for your water rollers? From what I have been told and read, it is especially important to keep tighter tolerances in your damper, especially if you are running alcohol free.

 

[QualityPrint]

Well we have done tracking over a few years and found that in our scenario this works best. There is always a balance with rollers between cost, scheduling, and performance. We have a tighter tolerance on our inkers because that is what we have found our durometer increase to be over our comfortable period of time. I don't think our water roller tolerance is too loose but maybe our inker tolerance is a little too tight. In regards to our water rollers, we see our 7-10 increase anywhere from 6 to 10 months into the life of the rollers depending upon workload. After our water roller durometer exceeds that limit we find that we have increased instability, scumming etc... but not before a 7. In my time in the industry I have learned that "by the book" doesn't always apply in your situation. So my approach is to gather as much information over an extended period of time to find out what works for best in my situation. The "by the book" info, for the most part, is just a guideline and guidelines to me can be tweaked. Our roller program is ever changing as we gather more information over time.

hope this helps

 

[STW100]

What is your deep cleaning process and time frame? Meaning do you ever use Feboclean & Calciumfix? How often? I'm not real familar with Komoris but I am a Bottcher dist and would be happy to get you a roller quote.
Stan, Intermountain Press Service, llc. ipsqm46.com

 

[QualityPrint]

We use Bottcher now and do febo and calcium fix at least once a week.