One of the key tenets in the Stephen Covey book, The 7 Habits of Highly Effective People, is to “begin with the end in mind”. This applies to many areas of business and life, and quite relevant for developing products with components that require custom tube bending.
Thinking through how the part will eventually be manufactured can help inform product design, and give better visibility to costs, options and timelines. Specific things to consider are tooling, bend radius, machine technology, tolerances and materials, among other things. In this regard, collaborating with a trusted tube bending supplier early in the design stage can reap benefits at the end.
Think about this:
- A bend die is required for pipe and tube forming. Most suppliers will have a variety of this type of tooling; however, if a bend die does not exist for your desired radius, tooling may need to be created to meet the part specification. This can be costly, depending on size and material. Asking your vendor about available tooling early on can be helpful.
- As a general rule, the tightest achievable center line radius is one times the pipe or tube diameter. Whenever possible, give yourself some flexibility by choosing a center line radius that is 1-1/2 times the tube diameter.
- In the case of parts with multiple radii, a straight length is needed for the machine to grasp the pipe or tube between the bends. Standard tooling can accommodate a distance between bends of at least 3 times the tube diameter. Bends with a distance less than 3 times the outside diameter may be good candidates for freeform bending. Another option would be to use compound bend tooling.
- When designing a part there can be a tendency to play it safe with dimensional tolerances, but for cost efficiency it can be helpful to keep them only as tight as necessary as tighter tolerances may add labor. Information on which tolerances must be met should be included in your project scope.
- In an effort to economize on raw material costs, some product specs call out thinner walled tube or pipe. Keep in mind that a thinner wall may add more set-up for the bend to ensure consistency with the shape and eliminate the chance of wrinkling. In some cases, these added labor costs may outweigh the anticipated material savings.
The type of machine technology being used can also be a factor to consider. It’s important to have a vendor that has a solid base of up-to-date equipment and the technical expertise handle the needs of your project. Start researching vendors and have a list ready.
Having a basic understanding of what is involved in the bending process, and consulting with your supplier can be informative during the product development process to help decipher project timelines and costs. For information or to discuss an upcoming project, share your details here.
This blog was authored by Patrick Coenen, Project Engineer, Sharpe Products. Patrick can be reached at patrickc@sharpeproducts.com.