NASCC 2010

Come and check out Cleveland Punch and Die at the NASCC Steel Conference in Orlando, Florida this year. The show will take place May 12-15, 2010 at The Gaylord Palms Convention Center. CPD will be in booth #613. Check out this floor plan for a visual view of our location and the location of all the exhibitors at the show this year. You can also check out the NASCC website to register for the show or find out more information. As always, we are extremely excited for the opportunity to meet new customers as well as see our friends and dealers throughout the industry. We hope to see you there!

Lubrication - Punch Easy

The Cleveland Punch and Die tip of the day is perhaps the most important when it comes to punching; the use of lubrication (Punch Easy). Lubricating the tooling on a punching machine can play an influential role in extending tooling life. Understanding the forces that occur in the space between the punch and the material being punched may help explain why lubrication should be used. As the punch passes through the material, tiny amounts of the material are fused to the punch surface. As punching cycles continue, layer upon layer of material is deposited on the punch, causing the punch diameter to actually grow. The clearance between the punch and die eventually becomes so small that the punch may become pressed into the die. Lubricants act as a barrier between the punch and the material, which will significantly reduce the amount of material deposited on the punch, thus prolonging its life.

The most commonly asked question when it comes to lubrication is "Which kind of lubricant works best?" Obviously, the higher the viscosity, the greater the protection. The higher viscosity works especially well for slowly retracting punching applications. However, on fast-cycling punching machines, the protective barrier on the sides of the punch can become a sticky, air-displacing vacuum generator on the face of the punch. During the fast retraction of the punch, the slug may pull out of the die and actually adhere to the punch face.

As mentioned earlier, CPD recommends our patented lubricant Punch Easy. Punch Easy is a non-pigmented, honey colored, heavy duty, odorless punching and shearing oil for thick materials. It is used on ferrous or non-ferrous metals where scoring, galling and friction is a problem. Its is a particularly good punch and shear oil for thick, high carbon steel, armor plate, grader blade, farm implement tools and stainless steels. Punch Easy is unparalleled for high production and multiple stage punching or stamping operations. Actual pyrometer readings indicate an operating heat reduction in drawn parts, punches and dies of as much as 40%. Punch Easy is to be used for cold applications and is not designed for any hot applications. Punch Easy may be used right out of the container or diluted with light mineral oil or "Easy Thin" for less severe jobs. Punch Easy is available in quarts, gallons, 5-gallon pails, case lots, and 55 gallon drums. Easy Thin can be purchased in gallon containers and works best when diluting Punch Easy. Call your CPD representative to order your Punch Easy today!!

The Operator is King

The Cleveland Punch and Die tip of the day is having an educated operator. The operator controls many factors pertaining to tooling life. The operation of a punching machine is a learned skill and the operator should be familiar with all functions of the machine as well as all safety features. Extreme pressures are generated when punching holes, therefore safety should be of the utmost concern to the ironworker operator. Guards should always be in place before the operation of any machine and the user is responsible for the machine and tooling to be set-up properly in order to avoid injury. Achieving "More Holes Per Dollar" will always be a fabricator's top priority, especially in these difficult economic times. By following the basic procedures that have been discussed in this blog, tooling life will surely be extended. In turn tooling costs will be reduced, profits maximized and a competitive edge will be obtained.

Round The Square Corner

The Cleveland Punch and Die tip of the day is to round the corner! Tool life can be influenced by the shape of the hole being punched. Tooling with sharp corners, like a square or rectangle, will break down much faster than tooling with a rounded corner. For square and rectangle holes, a 1/16" or larger corner radius will significantly extend tooling life and is recommended whenever possible.

Material Thickness Versus Punch Diameter

The Cleveland Punch and Die tip for the day deals with the relation of material thickness to punch diameter. The thickness of material being punched plays a significant role in punch and die life. This is especially true when punching holes where the diameter of the punch is close to, or greater than the thickness of material. During the era of the mechanical punching machine, the general rule of thumb that has been practiced is to not punch material thicker than the diameter of the punch.

Since the beginning of the hydraulic punching machine, the shock once associated with mechanical punching is minimal. Although, in certain applications, extreme pressures may be generated when holes are punched in material that is thicker than the diameter of the punch. The pressure and wear on the punch and die is greater during this type of punching and will consequently shorten tooling life. While we don't suggest engaging in this type of punching, we do know that there are applications where it can not be avoided. In these circumstances, we would recommend plenty of lubrication (Punch Easy) and extra clearance to provide some relief on the pressure exerted to the punch.

Know The Material Hardness

The Cleveland Punch and Die tip for the day is knowing the hardness of the material being punched. Punches and dies used to pierce holes in A-36 steel structural beams, plate, or sheet metal should be confined to and used only on these types of materials. Attempting to punch certain materials such as armor plate or spring steel will often exceed the capabilities of the tooling, causing it to fail.

When dealing with material hardness, factors involving the thickness and diameter limitations must be considered. The diameter of the punch must be such that the punch's compressive strength is greater than the force required to pierce the hole. This punching force can be found by multiplying the material thickness by its shear strength in PSI, then multiplying by the length of the cut. The general rule of thumb is to never punch a hole where the punch dimension is less than the material thickness. (ie, 1/4" punch through 1/2" material)

The maximum allowable compressive stress depends on the type of tool steel from which the punch is made, and its hardness. For example, oil-hardened, shock resistant tool steel will withstand 300,000 PSI compressive stress before breaking and can be used at 250,000 PSI with good tool life. Other tool steels can also be considered, depending on the material to be punched. When ordering punches and dies, the user is responsible for advising Cleveland Punch and Die of the type of material, the hardness and the thickness of material being punched. Having this knowledge will allow your CPD customer service representative to provide the highest quality tool for your specific application.

Check the Clearance!

The Cleveland Punch and Die tip for the day deals with the clearance between the punch and die. The clearance not only affects the punch and die life, but also the appearance of the hole. The clearance is determined by material thickness as well as the type of material being punched. Using correct clearance will result with approximately the top one third of the hole measuring the size of the punch and the bottom two thirds flaring to the approximate inside diameter of the die.

Insufficient clearance usually causes a secondary shear to be generated, resulting in additional wear on the punch and thus reducing punch and die life. Excessive clearance may result in a large flaring or "blow out" as well as a burr on the bottom of the material. Material "roll-over" may also occur along the top edge of the hole which will cause the punch's sharp edge to break down rapidly.

This figure shows an example of the effects of excessive and insufficient clearance:

No exact science exists for determining the proper clearance between the punch and die. What may work well for one particular type of material may be unsuccessful for another. However, the following chart provides good guidelines when punching A-36 mild steel:

    Material Thickness                     Die Clearance

1/4" up to 1/2"                              1/32"

1/2" up to 3/4"                              1/16"

 3/4" up to 1"                                 3/32"

1" and over                                  1/8"

When punching material other than mild steel, refer to the follow table:

Following these clearance guidelines will surely increase the life of the punch and die, resulting in "More Holes Per Dollar".