Considering the following factors when designing with perforated metal will result in the most cost effective quality solution.
Material type
When choosing a material type, look at both the application demands and the total product cost. More expensive high strength alloys may provide a better overall solution, if a reduction in thickness can be achieved. The stiffness and hardness of the material determines what hole sizes and patterns can be perforated. Also realize that a commonly perforated material is more readily available than a specialty one.
Material thickness
Thinner materials typically perforate easier and faster, and are often less expensive. The right material thickness provides sufficient strength to the product while allowing the perforating of the desired hole size.
Hole size
In general it is advisable to use a hole size larger than the material thickness. The closer the hole size and material thickness come to a 1 to 1 ratio, the more difficult and expensive the process is. Dependent on the material type, smaller hole size to material ratios can be achieved. Contact your Sales Representative to discuss your special requirements.
Hole shape and pattern
We have tooling available for many different hole patterns and shapes. It is more economical to choose one of the available patterns, although special hole sizes and patterns can be accommodated at additional cost.
Open area
Obviously a hole size and hole pattern has to be chosen that meets the open area requirement of the application. Keep in mind that punching holes in a material adds stresses that can result in distortion of the product. The higher the open area, the more material distortion takes place, especially when the perforated pattern is bordered by margins on all four sides. These distortions can be removed by our special in house leveling process, leveling requirements should always be discussed with your Sales Representative.
Margins
Our perforating presses can be programmed to allow a wide variety of margins. However margins prevent material from releasing stress built up during the perforating process and can cause flatness tolerance and camber issues. This occurs especially with high open area patterns, with margins that are wide or unequal or with margins on all four sides. Thicker and harder materials aggravate this effect. Additional leveling steps can be applied to reduce stress, but the distortions can be so severe that normal tolerances cannot be met. In that case, consider changing one of the design parameters to reduce the effect.
End patterns
A finished end pattern is often more expensive than an unfinished end pattern . If not specified, unfinished end patterns will be offered.
Tolerances
As with other manufacturing processes, tolerances tighter than the standard tolerances will result in increased cost. Where possible, stay within the standard tolerances.
Surface finish
Perforating, leveling and shearing normally leave slight surface imperfections behind that are considered acceptable in the industry. If required, special precautions such as vinyl coated material and paper interleaving can be taken, at additional cost.
Cleanliness
The perforating process requires the use of lubricants, and unless otherwise specified, perforated products are supplied with an oily film on the surface. A degreasing step can be applied, but consider that the oil also works as a protective layer.
See our Perforated Metal Technical Info section for additional information on materials, tolerances, hole pattern and other issues that can ipact your product desigin:
|
