Bob Want

Bob Want is a technical tooling sales and application analyst with Tools For Bending Inc.

Telephone: 800 873-3305

"Avoiding Common Bending Problems with Common Sense"

Bob published an excellent article titled Avoiding Common Bending Problems with Common Sense in the December 2006 issue of TPJ. In the article he presses the point that proper understanding of the importance of choosing proper bend tooling cannot be understated.

Psychology of Choosing

His starting premise starts with the psychology of the choosing bending equipment. Bob has noticed that fabricators are often tempted to "go with the the gut instinct and...the flashiest solution." His point is that fabricators should resist that gut instinct and "try to use a methodical, calculated approach."

The Method of Choosing

The rest of the article dicusses the method that he suggests. You'll find ideas like keeping the solution as simple as possible (not any more complex or bigger and more powerful than necessary) are the constant themes through this article. That approach makes this article a gold-mine of information for engineers trying to learn the mysteries of tube fabrication.

Bender Basics

In the BENDER BASICS section, he has a short discussion the "keep it simple" paradigm regarding choosing benders. This discussion is more brief than I would have preferred, but it is a start. For example, I recommend that a few other variables be introduced regarding bender types. For example, any fabricator of mulitple bend parts that must change between parts periodically on the same machine should almost always choose a full three-axis CNC rotary draw bender rather than a one-axis NC bender (that controls only the bend arm). Furthermore, any application that has rotation (twist) between bend planes is a prime candidate for a rotational axis. One of our customers that replaced many of their NC machines converted CNC benders was able to more than double production from automating the Feed/Rotate axes.

Selecting a Bending System

His rule of thumb regarding centerline radius to centerline height is interesting: "if the centerline radius of the bend die is the same as or less than the centerline height of the bend die, the bend die stability under load in the bend cycle witll be compromised." TFB has solutions for this problem, but it is more costly. The job quote should be increased accordingly. Also, he discusses the idea of why at least two benders (CW AND a CCW) of the same capacity can be necessary. To newcomers, the term CW and CCW may be a little confusing at first: A CW bender is also called a RIGHT HAND bender. If you stand in front of the bender and reach out with your right hand to pull on the bend arm, your right hand will touch the part that swings outward. CCW benders are also called LEFT HAND benders. If you extend your left hand to the bend arm, then your left hand will touch the part of the arm that swings outward.

Conclusion

He finishes with this advice: "Before casually requesting all the bells and whistles when comparing tooling quotations, consider the simpliest solution to your needs first." I like that advice, and think its practice saves a lot of headaches for fabricators.

Link to the Article

Read the article at the TPJ site

--Mcone 09:14, 7 February 2007 (EST)