Category Archive: Perforated Products

3 Traits of Perforated Sheets to Identify before Ordering from Your Manufacturer

Perforation of material is accomplished by using mechanical means to penetrate, or “punch”, through material surface, leaving behind a hole of particular size and shape. In practice, perforated material typically consists of flat sheets that are modified by creating recurring patterns of punched shapes.

Implementation of perforated products into any project requires knowledge of the cost implications associated with specific metal configurations. It is important to understand the various characteristics of a sheet and the options available when specifying the product to be produced.

Before ordering custom perforated sheets, the buyer must typically specify these three traits:

1. Material Type and Thickness

There are many types of materials suitable for perforating, with what is most applicable for the specific projects dependent upon the material cost and properties. Commonly used materials for perforated metal are:

• Hot-rolled and cold-rolled carbon steel
• Galvanized Steel, typically pre-galvanized (galvanized prior to punching)
• Stainless steel (Type 304 and 316, both standard and low carbon varieties)
• Aluminum
• Brass
• Copper

Material thickness is also important to consider, especially since the cost of fabricated pieces is typically derived from the “per pound” price of the material, and perforated pieces are no exception. The thinner the perforated sheets, the less material used to create the finished piece, and therefore the lower the price per piece.

In addition to simply saving on material cost, it is easier for shops to punch and work thin(ner) sheets than it is to machine thicker pieces, which creates an associated savings in production costs as well. It is important to remember, however, that decreasing the cross-section of the sheets by choosing a lesser thickness will create a decrease in the structural capacity of the sheet.

Utilization of higher-strength pieces can, in some cases, result in an overall reduction in the number of pieces that are required. The designer must balance material thickness versus structural requirements to ultimately decide on the best way to achieve a cost-efficient project.

2. Hole Shape and Size

Perforated product producers are able to create a wide array of hole shapes and patterns in material sheets through the use of standard and custom punches, computerized punching pattern programs and special fabrication techniques.

• The types of hole shapes available in perforated products is limited only by the technological ability to machine the cutting dies into a specific configuration that can not only create the shape, but withstand the stresses of the punching process. A round hole is the easiest and most economical shape to incorporate into a perforated sheet, as the relative simplicity of machining a round piece results in low manufacturing costs.
• Hole size is determined by drawing a circle around the hole shape with a radius that extends from the center of the shape to its extreme outside edge. Typically the hole size is greater than or equal to the thickness of the material being punched, in most cases much greater. For high-strength material such as stainless steel, the hole size must generally be at least 2 to 3 times the thickness of the metal sheet in order to provide a clean cut, easier manufacturing and reasonable cost.

3. Margins

The end margin width on perforated sheets is normally zero, which means that there is no distance between the perforated patterns and the end of the sheet. This is known as an “unfinished pattern” and occurs when the punching continues to the ends of the sheet and the holes do not complete their last cut cleanly inside the sheet borders.

Stock sheets are most commonly available in an unfinished pattern configuration. It is also the least expensive way to fabricate a piece from scratch. If desired, a minimum margin width can be created on the ends, but require adjustments to the perforation process, resulting in more expensive sheets.

Learn More about Criteria Involved in Manufacturing Perforated Sheets

Knowing the exact specifications of your perforated product can help accelerate the project’s completion — and lets you know what to expect in terms of cost and timeline. To learn more about the factors that go into selecting your product, download our new eBook, Proper Selection for Perforated Products.

Choosing the Right Perforated Metal Pattern

Perforated metal has applications in a wide spectrum of industries, ranging from pharmaceutical to construction. It is created through metal stamping and characterized by a pattern of holes in a sheet or strip of metal. Depending on its intended use, perforated metal comes in a number of standard, as well as a wide variety of custom holes sizes, shapes and arrangements to meet the special requirements of each application. To select the right perforated metal, you may have to consider variables such as strength, applications, and ratios in hole and bar size.

Strength Considerations in Perforated Metal

The strength or stiffness of perforated metal sheets can be a crucial factor when used in stress conditions. This is especially the case when it is used as a protective layer in sound-proofed walls, as well as outdoor barriers or even pieces of furniture. Naturally, perforated metal is not as strong as non-perforated metal.

However, the two are compared to establish strength levels of perforated metal. This allows design engineers to determine what thickness of perforated metal will deliver the same strength of non-perforated metal. The strongest hole shape and pattern for any given percentage of open area is a 60-degree staggered, round hole pattern.

Selecting Perforated Metal for Specific Applications

The application of the perforated metal is another important factor. Perforated metal can be used to sound-proof rooms, shield radiation, and distribute heat, among many other uses. As an acoustic barrier, it causes sound waves to move in and out of the holes quickly, absorbing them into a sound absorptive layer underneath.

Perforated metal is also used in microwave ovens to contain radiation while letting heat pass through. The effectiveness of perforated metal in all of these various applications, however, depends on the size and number of holes in the sheet.

Hole and Bar Size in Perforated Metals

As a result, you should also consider the ratio between hole and bar size in a sheet of perforated metal. Bars are the spaces between the holes, occupied by metal. The balance between holes and bars in a sheet of metal can affect its strength and efficiency in different applications. Narrow bars indicate larger holes, while wide bars suggest smaller ones.

While the variations of hole and bar sizes are virtually countless, your options may be limited by the general rule that the material thickness of the metal being perforated should not exceed either the hole size or bar width of the pattern. There are exceptions to this rule, but keeping this general rule in mind during your application planning is advised. This is to reduce the likelihood of tool failure during manufacture.

To choose the right perforated metal pattern for your application, you may have to consider a number of key factors. The strength, application and distribution of holes and bars in perforated metal all have an effect on its functionality and efficiency.

Non-Metallic Perforated Products

Many plastics, vinyls, laminates and composites can be perforated, as well as non-metallic coatings and coverings bonded to metals. If you are considering such an application, let us know!

If you need assistance in selecting a perforated metal pattern, the experts at Metalex can help. Contact us today or download our eBook, Proper Selection for Perforated Products.