The Offset Pressman

I asked this question recently to one of the head press installers for Man Roland.  So here is the answer.  It's time to change your pins when they are either damaged or worn.  Sounds simple, but it is apparently a little more involved than that.  If you work on a press folder that uses pins, you may be interested to know the three reasons he outlined for changing them.  They can help in troubleshooting folder problems .  1.  They get damaged.  This is when most of us pressmen change the pins.  They get bent or break off in a folder jam. Even then, if you are like me, you will not change the pin unless it is really bad. 2. Worn beyond bevel.  This is a less noticeable reason to change the pins.  Quite often at the tip of each folder pin, there is a small bevel that leads up to the point where the pin is meant to pierce the paper.  As time goes on, this bevel will wear down.  What makes it less perceptible, is that the bevel can wear down with it.  Once that bevel disa

How do you make the fastest printing press in the world?  You find the one part of the press that hinders it from going faster and innovate technology to improve it.  With web presses, it's not the printing units that slow it down.  It's not the flying paster and it's not even the basic folder.  Rather it is usually the chopper table itself. To deal with this, some press manufacturers have come up with technology to slow down the signature after the first fold (over the former board) and second fold (along the tuck and pin cylinders).  Man Roland has designed a patented form of brakes that stop the copy in its tracks to allow it to be pushed down to the quarter-fold nips. The thicker the product, the harder it is to stop.   Hence the 6 "skis" on each side of the chopper table are able to function independently to give a perfect fold. In fact, it gets better than that.  While running, fiber optic sensors located near the headstop will monitor how straight

Calculating blanket and plate packing is not rocket science, but is technical enough to have a calculator on hand.  At our shop we simply have a standard blanket and plate thickness, so there is really little need to sit down and figure this stuff out when it comes time to change packing.  However, having an understanding of the math behind it will make you a better pressman .  So here goes. First and foremost, the calculations below assume that your bearers are set properly .  Once you have those set, you are ready to start using this formula.  Let's start with your plate to blanket setting. Calculating Blanket to Plate Squeeze Your desired squeeze from blanket to plate is .005".  In other words, that is the total amount of the blanket and the plate being over the bearer height.  GATF recommends that the plate be packed .001" over bearer while the blanket is .004 over bearer (or whatever is determined based on your paper thickness).  Formula:  (Required pla

Description:  After the printed signature leaves the jaw cylinder, completing its first fold, the then enters the quarter-fold area.  If the quarter fold is engaged, there are functions of the process that can cause tears. Problem:  Tears happening at the lead edge of the signature. Description:  The lead edge refers to the part of the signature that is already folded once.  This copy just "kisses" the head-stop before being pushed down through the quarter-folding nips by the chopper blade.  This timing is critical for success. Solution:  This is most commonly a timing issue.  Adjust the timing of the chopper blade to allow the signature to barely touch the head-stop before going down.  If the chopper blade goes down too soon, it will cause an uneven fold as there is less control of the signature.  If the chopper blade goes down too soon, it will cause tearing issues.   Problem:  Tears happening at tail edge of signature. Description:  This is also related to timin

Managerial postures have shifted greatly over the years.  In the thirties and early forties, management operated in hard nosed direct order - you did it or else mode.  Industrial psychology had not yet reared its ugly head.  No manager of that era was concerned with labor saving devices.  Workers were supposed  to get tired on the job.  Indeed if you were to look at the workload of that era, you would find, on a high speed press, one man hand feeding ink to two eight unit presses.  One man tending to two roll stands.  Three men jogging four delivery points.  Each of these jobs required an almost breaking point physical effort.  I know all of these jobs because I did each on and believe me, I was glad to have had the opportunity. Physical amenities in those days were Spartan to say the least.  Dark, gloomy, noisy, ominous, was the norm for press rooms.  Absolutely no smoking was allowed even in the washrooms.  Smokers would sneak a smoke by exhaling into a flushing toilet to escape d

Description:  Tears can happen at many places in the folder.  However, this section refers to tears happening before it enters the chopper fold area.   Problem: Too much tension at former nose. Description:  Idler rollers immediately below the former nose are used for controlling tension as the web slides over the former.  Too much tension at the end of the nose itself will cause tears as the web travels down into the folder.  You will generally hear a cracking sound as the paper makes small tears. Solution:  Move the position of the idler rollers immediately below the former to adjust the tension. Problem:  Belts are not aligned to carry the signature properly. Description:  As the signature transfers from the pin and tuck to the jaw cylinder, it must be held by belts.  These belts must be aligned in such a way that they do not cause tears.  At times the belt may be torn or they may not be aligned against the signature properly. Solution:  Move the former board (and chopp

I've written before about safety hazards in offset printing , but this time I wanted to share a recent audit of the noise levels around our web and sheetfed presses.  Here is what we found.  The results are rated in decibels (dB) 72 dB at our sheetfed presses Press: Man Roland web press Near folder: 94 dB In front of printing units: 89 dB Between printing units: 108 dB Press: Heidelberg GTO sheetfed Beside delivery: 72 dB The results were not surprising on the sheetfed press as a recent study found that out of 10 sheetfed presses, the average 79.3 decibels.  That represents a minimal risk.  Here is how the industry ranks the above decibel rates. No Risk (0-40 decibels) 30 dB - A whisper 48 dB - Normal conversation Our web presses rated as high as 108 dB Minimum Risk (40-84 dB) 70 dB - Traffic 75 dB - Hair dryer 80 dB - Garbage compactor Moderate Risk (84-100 dB) 85 dB - Lawn Mower 85 dB - Blender 88 dB - Subway High Risk (100 - 120 dB) 105 dB - Tr