|Are You Square?
|Several problems can occur whenever the press isnít square.
Consider: Web wrinkles are present when one unit is misaligned with another unit or the folder. Print register is affected and may be impossible to correct. Driveline couplings and drive shafts may wear out prematurely.
The tools used to correct alignment problems will vary from press to press depending upon its size and the way the driveline is configured. A plumb bob, a quality level such as a machinist level, music wire (piano wire), tramming rods with a dial indicator (distance rods), and Kraft gum tape are the basic tools used to check and square up the units.
Typically, large newspapers hire alignment companies that use highly accurate surveying levels with recital scales that measure within a thousand of an inch. Other alignment companies will use sophisticated laser levels to do the alignment leveling and squaring since it is quicker to use; unfortunately if the distances being measured are very long the light beam will spread and will cause some inaccuracies.
The plumb bob is used to transfer center lines from one level of the press to another. The plumb bob can also be used to quickly check the press units for vertical alignment.
The machinist level is accurate within a thousandth of an inch; unfortunately the distance between the units is quite long. To check the height between the units a long bar such as a one-inch by two-inch machined bar could be used for this purpose at whatever length is necessary to span the distance to be measured or checked for level.
A music wire strung from one end of the press line to the other is the quickest way to find out if there is any major unit offsets. Normally the wire is stretched away from the press unit slightly so that a shim block can be used to check for accuracy. The block would normally be coated with a light oil and then passed between the press unit and the wire. When the units are in proper alignment the block can be passed between the press unit frames and the wire without moving the wire.
A tramming rod is used to check the distances between objects. A makeshift-tramming rod can be made using a telescopic rod, which can be easily purchased at a camera shop and drilled so that a dial indicator can be mounted to it. The other end of the home made device is normally fitted with a ďVĒ block or a flat plate that has a dowel fit into one end of the plate. This device can then be used to check to squareness of one unit to the other or from lead-in roller to main press cylinder or from lead-in roller to lead-in roller. Professional tramming devices can be purchased from a machinist supply store.
The Kraft gum tape is used in some cases whenever a tramming rod is not available. The tape is placed all the way around the two objects to be measured and at one end, such as two lead-in rollers, so that the tape overlaps at one of the rollers. Once the tape has been placed around the two objects so that the tape overlaps, a mark is made across the overlap. Next the tape is moved to the other end of the two rollers (drive side to operator side or operator side to drive side). The objects are parallel with one another if the marks on the tape meet. If the marks on the tape donít meet then the objects will have to be repositioned.
It pays to be square. It will reduce your newsprint waste, improve print register, reduce labor costs and will cut your repair costs.
Frank Bourlon has more than 30 years experience in the newspaper industry. He is the executive director for Newspaper Production & Research Center. He can be reached @ 405-524-7774 or via email at email@example.com.
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