The following insights are offered on each of the factors that affect the quality, cost, and delivery of perforated product. To achieve a high quality, low cost product that is deliverable within a timely manner, it is recommended that these factors be considered when designing and/or specifying perforated material. They are:
Material Type
While using a material that meets the demands of the application is most important, choosing one that is commonly perforated is likely to be more readily available than one that is not. If important, specify material origin (i.e. Domestic, NAFTA, or other) and/or CERTS needed when requesting a quote. Failure to do so at that time may result in having to re-quote the requirement due to increased lead times and/or price.
Material Thickness
While materials of varying thickness can be perforated, full width perforating presses are designed to handle materials that range between .004″ to .25″ thick. As the limits are approached, the stiffness and hardness of the material dictates what can be perforated and in which patterns.
Hole Size
While a wide range of hole sizes can be perforated, the ability to produce them is dependent on the thickness of the material. As a rule of thumb, a greater than 1 to 1 ratio should be maintained (i.e. 1/8″ holes in 1/16″ thick material). In the event that the hole size is close to, equal to, or less than the thickness of the material, the greater the likelihood that punches may break – resulting in either imperfect or missing holes in the material. For this reason, where applications require the 1 to 1 ratio to be either pushed or exceeded, it is best to discuss with a Customer Service Representative the level of allowance for imperfect or missing holes and the cost associated with meeting that level.
Hole Shape and Configuration
While using a hole shape (i.e. round, square, slot, etc.) and configuration (i.e. staggered or straight) that provides the best solution for the application is important, choosing one that can be produced with existing tooling minimizes costs and enables faster delivery.
Open Area
While choosing a pattern that offers the required percent open area is of great importance, patterns with extreme open area proportions (i.e. 60% and higher) increase material distortion and can adversely affect quality and/or increase costs resulting from efforts to minimize the distortion. This is especially true when the perforated area is surrounded with margins on all four sides.
Margins
While they can be made in practically any size and can omit the need for having to weld perforated material to non-perforated material, margins can increase the difficulty in getting material within a desired flatness tolerance and can cause camber. This is especially true when:
• margins are wide (i.e. 3″ or more)
• margins are unequal
• margins are on all four sides
• the material type is hard (i.e. Stainless Steel 300 series, 1/2, 3/4, and full hard aluminum)
• material is thick (i.e. 11ga or more)
• the perf pattern is of a high open area (i.e. 40% and higher)
To minimize the amount of work and the associated cost required to get the material flat and without camber, either reduce or change one or more of these attributing factors. If unable to do so, consideration may have to be given to allow for less stringent tolerances.
End Margin Pattern
Unfinished and Finished
While it is considered industry standard practice to produce perforated areas with unfinished ends when enclosed within margins, finished ends can be produced providing that the tool is capable of doing so. In most cases, producing finished ends requires the employment of special production techniques. For this reason, finished ends may increase costs. To find out if a desired pattern can be produced with finished ends, contact one of our Customer Service Representatives. Unless otherwise specified, unfinished ends are quoted and produced.
Blank areas and/or Locator holes
While it is likely that blank areas and/or locator holes can be made in any pattern, the ability to do so is dependent on the versatility of the tool (i.e. center spacing). To find out if either desired blank areas and/or locator holes can be provided with existing tooling or if tooling would have to be modified or developed, provide us with a drawing of the part and a member of our staff will advise you.
Tolerances
While it is our intent to meet all desired tolerances, the ability to do so is dependent upon the workability of the material and the cost that is willing to be incurred. Two tolerance grades, Diamond Standard and Diamond Superior, are available providing that the material can be worked to within both ranges. Unless requested, Diamond Standard tolerances are held. To ensure that critical tolerances are held, specify Diamond Superior.
Surface Finish
While measures are taken to keep surface blemishes to a minimum, imperfections resulting from perforating, roller leveling, and shearing do occur and are therefore considered standard and acceptable. If material surface finish is critical, then it should be indicated on the request for quote so additional precautions (i.e. use of vinyl coated material, paper interleaving, etc.) are planned for and the cost is adjusted to consider the additional detail.
Degrease, Fabricate, and Finish
While perforated product can be supplied degreased, fabricated or finished, unless requested, these secondary operations are neither quoted nor performed. Although they may prolong delivery, secondary operations add value to your perforated product. While they increase the cost per part, letting Diamond perform these operations is easier and often costs less than what it would be if done by the customer.
Packaging & Labeling
While material can be packaged and labeled to customer specification, anything more elaborate than Diamond standard may increase costs. To calculate the number of skids required to complete the shipment and to ensure that product can be unloaded at the time of delivery, the max. skid weight and unloading capabilities should be communicated to the Customer Service Representative at the time of quoting. Failure to due so may affect the packaging cost and possibly result in problems when unloading material.
