785.271.5816 | info@fsea.com



Technology Focus

Automated Rule Bending Systems

by Robert L. Carter

May-June, 2004
One of the most exciting new technologies to be developed in the last several years for the diemaking industry are fully-automated rule bending systems - a technology that provides significant benefits to both diemakers and diecutters.

Essentially, there are three distinct types of systems in the broad classification of automated rule processing equipment. Although many lump these into a single category, it is important to differentiate between them in order to eliminate confusion and to establish common terminology throughout the industry. Machines that do not bend the steel rule but instead, cut, miter, notch and, in some cases, mark bending positions on the rule, will be referred to as ‘automatic rule processors’. Machines that perform some or all of the ‘processing functions’ (including final cutting, mitering, and notching), and also bend the rule - all within a single machine - will be referred to as ‘automatic rule benders’. Finally, there are multiple station systems, which process on one machine and bend on another, as at times, bending is first while at other times, processing is first. Since all of these systems require individual pieces to be manually handled one or more times, they do not fit into the category of automatic rule benders but could be more properly classified as semi-automatic bending and processing systems. Examples of what I have called automatic rule benders, machines which do it all in a single station, would be the machines sold by Ken Specialties, Helmold, and Adams Technologies.

The first rule processors/machines that could cut, miter, and notch the rule were introduced into the market in the mid 1980s. The earliest machines required manual programming. During the late 1980s, a computer interface was added, which enabled the individual part parameters such as length of piece, number and position of notches, etc., to be downloaded from the CAD files. These are similar to the systems that are currently being marketed as automatic rule processors.

The first rule benders were introduced in the early 1990s. The earliest machines were pretty much limited to bending. The final cutting, as well as the notching and mitering, were done on a separate, stand alone machine. These were the first of the semi-automatic bending systems.

The current generation of automatic rule benders, as previously mentioned, do the bending and perform most or all of the processing functions of cutting, mitering, and notching in a single machine. These types of machines were introduced to the marketplace in 1997.

How it Works
When working with an automatic rule bender, the first step is to load the CAD file. Basically, the data from any CAD system can be utilized by any of the automatic machines. However, it is important to remember the old axiom - garbage in, garbage out. A poorly constructed CAD file will not work well on any of the automatic rule benders. Gaps in lines, arcs that do not intersect straight lines, overlapping lines, poorly digitized files and files that have been improperly converted from graphics programs such as CorelDRAW® and Illustrator® are some of the file issues that will severely limit production and drive your operator crazy. One company that sells automated bending systems has stated that 90 to 95 percent of the problems it sees are related to the quality of the CAD file and only 5 to 10 percent are caused by the machine, the die, the steel rule, and all of the other things in the diemaking process that can go wrong. Obviously, a good CAD file is a critical requirement.

Once the file has been loaded, it appears on the screen of the bender. From this point forward, the automatic bender is just like another diemaking tool. The machine replaces the manual portion of diemaking with mechanical aids: electric, pneumatic and hydraulic. The computer interface, along with the CAD system, provides all of the dimensional and numerical data. But it is up to the diemaker to tell the machine what to do - where to break the rule, where to start and stop each piece, when to use miters and when to use straight cuts, when to add run through, when and how much to open or close bends and so on. Again, the automatic bender is a tool. And yes, it’s a very good tool. Some would even argue that it is the best tool ever introduced into the steel rule diemaking industry - even better than the laser. But it still takes a knowledgeable person to operate it - a person who is familiar with the basic principles of diemaking.

Next, let us examine what is necessary to produce the rule for the dieboard. Obviously, the specific procedures and operations depend on the type of machine being used. However, the operations required to operate any of the automatic benders are very similar. First, select the starting point of the first piece to be produced and the direction of travel. Next, select the end point of the piece. Confirm that the start and end points are correct. Then, assign a part name to the piece. In some cases, the computer will automatically assign a sequential part number. At this point, the computer needs to know a few things about the piece - specifically, how many of the pieces are required, is there a miter or straight cut on the starting end of the piece, and is there a miter or straight cut on the outer end of the piece? At this point, the information is confirmed and the piece or pieces can be produced.

In hand will be the final piece - cut, mitered, notched and bent, and ready to go into the dieboard. From this point, another piece can be set up through selecting the start point and direction of travel, selecting the end point and confirm, naming the part, entering the variable data, indicating the number of pieces and the type of cut on each end of the piece, and finally, running the piece.

Limitations
All automatic benders have some physical limitations. For example, some machines can produce sharp bends of up to about 1.25 degrees on 2 point rule. This means that bends of more than 125 degrees will have to be finished on a hand bender. However, the machines also provide the ability to make corrections to pieces, which, for one reason or another, do not fit perfectly into the dieboard. On certain automatic benders, any line can be lengthened or shortened by any amount; arcs or sharp bends can be bent more or less; and either of the end cuts can be extended or shortened. On the typical folding carton or corrugated die, 95 percent or more of the pieces should go directly from the machine to the die without any adjustment or handwork. The balance of the parts will require some handwork such as angle grinding joints and finishing bends that were beyond the machine’s physical limitations. On other types of dies, especially on those with a lot of relatively small “freehand” shapes, the percentage of pieces requiring adjustment and handwork will be higher. At worst case, 70 to 75 percent of the work would be done by the machine, leaving 25 to 30 percent of the work to be done with traditional diemaking tools. This would be more typical of jigsaw puzzle dies and work of this nature.

Productivity Improvements
The amount of total productivity improvement will depend on several factors, including the type of die work and how well the type of bender fits that particular type of die work, the efficiency of die shop, the type and condition of the hand tools available, and the experience and skills of the diemaker. Productivity improvements from a minimum of 2 to 1 to as high as 6 to 1 have been documented by current users of automatic bending systems. The average is in the range of 3 or 4 to 1. Again, there are numerous variables to be considered, and what is true in one shop may not be true in another. However, the worst case is that productivity will at least double.

Steel Rule Limitations
There are little to no limitations with the type of steel rule that can be used with an automatic bender. All of the machines can be calibrated to run any brand and almost any type of rule. However, a word of caution is in order. The quality and consistency of the steel rule are much more important in automatic machines than they are when using traditional hand benders. When a machine has been calibrated to apply a certain amount of pressure to generate a specific bend, it will always apply that amount of pressure for that bend. If the rule hardness is not consistent from coil to coil or from batch to batch, the same pressure will obviously produce a different bend.

Training Period
The training period will vary but in all cases, will be relatively short. It will usually take a few days to learn the basics, followed by a few weeks of gaining experience, confidence and speed. In many circumstances, it may be better to start with a diemaker who knows how dies go together and how to set up and bend by hand when necessary. It certainly doesn’t have to be the most experienced or highly skilled person, although it may be. A diemaker who has had some CAD training would probably be an ideal operator as he could more readily identify and fix file problems, but people with those credentials are hard to find. And it is always better to find and fix file problems before releasing the file to the diemaker. Obviously, it would take much longer to train someone with no prior diemaking experience.

Hopefully, this article has provided an insight on automatic rule bending systems and the advantages they can provide a diemaking/diecutting operation. Once the rule has been properly bent, all that is left is to cut and insert the score rule, add the rubber and the die is ready to run. n

This article was adapted from materials that were submitted as part of a program conducted by Robert L. Carter of Adams Technologies, Inc. at the International Association of Diecutting and Diemaking’s Diecutting Odyssey. It has been printed with permission from the IADD. IADD can be contacted at (815) 455-7519 or visit: www.iadd.org.