The Time of Day When Errors Happen

What time of day do mistakes most often occur?  That was a question we put to ourselves recently in an effort to see if we could find a pattern.

Everyone makes mistakes.  But what I would like to offer here is some research we did into finding the time, frequency and cause of mistakes in our press room.  True, they are not avoidable.  But as Bram Stoker said in Dracula, "We learn from failure, not from success!"  So I would like to share with you something insightful and practical that you can learn from and apply in your press room.  I don't present the solution, but a way of learning from it.

First of all, I would like to draw your attention to the chart below.  It shows the frequency of mistakes and press downtime associated with all mistakes made on our presses and auxiliary equipment.  We record and make a log of every mistake that takes place and this is the result of all the data compiled for two years.  I must add that we have a unique culture in our press room to honestly admit and record our mistakes.  But that's the subject for a future article...

Time of Day and Number of Mistakes and Downtime
The green line above shows the number of occurrences while the blue bar represents how much press downtime resulted.  Do you see a pattern?  Remember it is the culmination of 2 years data and it shows definite patterns.

Our press crews generally work an 8-5 shift and the occasional double shift.  What we see in the graph is a spike in errors first thing in the morning.  Then another spike between 11:00am and 12:00pm.  That one hour represents the highest number of  errors of any time of day and then tapers off the rest of the day until 5pm.  So the natural question we asked ourselves was - why?

We do not have any patterns in our printing schedule.  In other words, there is no print job that comes along on a daily basis at that time. In fact, none of the work we do starts or finishes at that particular time.  There was only one thing we found.


At 11:30 our press crews start a lunch rotation.  They go eat for 20 minutes and then return to the press.  This process starts in earnest at 11:30 and tapers off until finished at about 12:30.  During this time a little dosey doe takes place.  The crew members "cover" for one another while the press runs.  When we discovered this link, the cause was obvious.  The lesson?

  • Mistakes Occur When Crews Change
  • Running Short-Handed is Not Effective

It's hard to prove those conclusions without a wealth of data to back it up.  A short sighted viewpoint would conclude that there is little effect on press production.  And that running short handed may even save an employer some money.  But as the data shows, the employer pays in other ways.

So how do you avoid it?  Here I offer no solution as I said at the outset.  Everyone has to eat. People have to go the bathroom.  Inevitably, pressmen will have to cover for one another. Perhaps a better question would be "How do you minimize these factors?"

What We Did

We have since taken steps to ensure that the crew is never short handed.  Management comes out if need be to help relieve those going for lunch.  We also try to avoid lunch rotations when doing complex make readies.  Beyond that, it's hard to come up with a solution.  But hey, solving print problems was never easy anyway.

Ink Leveller Add-On That Makes it Work Right

I recently discovered a small tip for ink level control.  Please take a look at the ink level bar above.  It controls the level of ink in our yellow ink fountain.  The bar across the fountain supplies the ink, but please notice the the tips just underneath it.  Each tip has a small valve.  We put them on recently for two reasons:
  1. The leveller did not supply ink evenly to the entire fountain.  It's a natural that it loses pressure as it passes each valve on the way to the end of the fountain.  Notice that the tip closest to you in the picture is wide open.  As you go to the other end, the valve is almost closed.  Why?  To account for the drop in pressure.  Now our fountain fills evenly when it turns on.  The result is ink that is fresh all the way across the fountain.
  2. The leveller does not leak when not used.  Sometimes we pull it out to change ink or clean the fountain.  We now simply turn off all the tips and nothing leaks out.  
The valves themselves were not that expensive, but with six tips per leveller it adds up when you outfit the entire press.  It's an upgrade to the leveller that makes it work right.  I'm surprised it didn't come standard with the press, but I highly recommend the upgrade. 

Press Parts - OEM vs Aftermarket

If you have the luxury of working in a printing plant that uses only OEM parts, my hats off to you.  It says a lot about where you work.  For the rest of us that use aftermarket parts, I thought I would list the pros and cons of each since we have seen the pitfalls of both.  Even though you may not be the decision maker, I thought some of you would appreciate some of the pitfalls of each.



Good Quality - Your press manufacturer will provide the exact part you need, designed to do precisely what you need.  Plug and play.
Warranty - If the part doesn't work, a manufacturer will stand behind the product and usually back it up with some sort of warranty.  We have had this happen a couple of times.
Exact Parts - Finding parts is a no brainer.  The press manufacturer will have the exact part and you do not need to choose between different brands or types.


More Expensive - Manufactured in Germany?  Then that's the price you pay for German engineering.  Manufactured in China?  I guess you get what you paid for.
One Source - There is no choice where to buy the part.  You have one choice and you pay the price you are given.  I am certain that press manufacturers abuse this market like any others.  Just like buying the printer for your computer and then finding out the replacement cartridge costs more than the actual printer.
Quality is not always better - Many aftermarket parts produce better replacement parts than the press manufacturer itself.  You could be paying for just the name.

Aftermarket Parts


Cheaper - Hands down, usually the number one reason to buy them.
Availability - Most of our parts come from Germany when we order OEM.  Who has time to wait for that?  If there is a local parts manufacturer, you can wait hours instead of days.  Who has time to wait when the press is down?
Quality can be better - This can sometimes be the case.  Sometimes these aftermarket dealers improve on the part and try to get the edge this way.


Difficult to select the best - The selection can be difficult if there are too many choices.  Quality can vary.
No warranty - You will not always get a parts dealer that will stand behind their part with a warranty.  This helps to keep the price down.
Variations in quality - Aftermarket press parts manufacturers who have reverse engineered their parts will sometimes use inferior materials to keep the price down.  You get what you pay for.  

Which is best?

I worked at a company that was so cheap that they preferred we held everything together with twist ties.  I don't work there anymore, but I am now thankful just to get replacement parts - no matter where they come from.  Having said that, I cast my vote for OEM press parts.  Nothing beats the quality... as long as I don't have to pay for it.