Value of Hydroforming

A true value of hydroforming is in the forming of parts without wrinkles or tears

The secret is in a unique fluid forming process, which offers advantages over conventional mechanical and hydraulic presses. The value of hydroforming has been proven over and over again in the past 50 years with the manufacture of metal parts for such markets and industries as commercial lighting, cookware, defense, aerospace, and land based power generation.

The hydroform machine or press is different from the conventional draw press. A comparison of the two drawing processes with regard to wrinkling is summarized from information from the Precision Metalforming Association, Independence, Ohio:

Compare the matched die process with the hydroform machine. Generally, with a conventional press, the blank is first placed on the top of a lower die and then the blankholder ring is lowered, making contact with the blank. Next, the upper die is lowered to make contact with the blank and now the part is ready to be drawn.

When this starts, there is a relatively small amount of material out of contact with upper and lower die, but then as the draw progresses, more and more material is drawn from under the blankholder ring, ending with having no contact either with the lower or upper die. To restate this, as the draw ring progresses, more and more material is actually out-of-control.

This is usually what causes problems with tearing or wrinkling with parts on conventional matched die tooling. In addition, as the draw progresses, the upper die member absorbs energy, which takes some of the hold-down force from the blankholder ring. As this happens, , the flange area is getting smaller and the material is work hardening—which actually more hold-down force to eliminate wrinkles.

However, everything is completely different when using a hydroform. In hydroforming, hydraulic pressure in the forming chamber forces the flexible diaphragm to be in contact with the blank during the entire drawing process. There is never a time when the material is not “in control”: it is always between the diaphragm and the punch, flowing smoothly without the stretch lines, scuff marks and work-hardening often that often happens with conventional dies.

Additionally, as progress is made during the course of the draw, the oil pressure is increased—which gives greater hold-down forces on the smaller flange area of the part…the result? Pressures that range from 5,000 to 15,000 pounds per square inch.

This true value of hydroforming shows itself in savings on finishing costs. Scuff marks, wrinkling, and shock and stretch lines are avoided. The cushioning action of the flexible diaphragm essentially prevents these faults from occurring, saving in finishing costs.

Hydroforming and Jones Metal

Jones Metal Products Company takes pride in producing parts without wrinkles and marks. This value of hydroforming results in a reduction of time and cost of finishing a customer’s order. With eleven hydroform machines in operation, the company can form parts from blanks up to 32 inches in diameter. Blanking materials include aluminum, stainless steel, nickel-alloys, titanium, copper, brass, and bronze.

For more information on the value of hydroforming, contact Jones Metal today!

Sources:
Precision Metalforming Association, Independence OH.
H. Singh, Fundamentals of hydroforming, 2003, Society of Manufacturing Engineers, Library of Congress Catalog Card Number 2003105327.

A. Esposito, Fluid Power with Applications, 7th Edition, Pearson, Prentice Hall, 2009, Upper Saddle River, NJ.

Ed Myers, Operations Manager, Jones Metal Products Company.


 
Recommended Resources from the Hydroforming Experts

Check out our latest video featuring
a deep dive on hydroforming by Jones Metal Products. 

 

Related Links