In a part produced using air bending, the metal is placed between a punch and a V-die as shown below: As the press brake forces the punch and the die together, the metal folds where the punch makes contact with the part. A bend should be at least the radius of the curl plus 6 times the material thickness from the curl feature. In a bent sheet-metal part, the Bend Radius is the radius of the bent metal where the punch meets the part. Because the parts are going to be hung from hooks and dipped it is beneficial to design hanging holes into your part rather than leaving the decision to the plater. The "neutral axis" is where the material doesn't elongate or compress during the bend. When your bend angle is 90 degrees, Outside Setback is the distance between the start of the bend radius, and the edge of the flange (see the picture below). Avoid recessed areas which are difficult to reach. Assume all areas of the part will be plated, masking is not recommended. From another dimple, dimples should be 4 times material thickness plus the inside radius of each dimple. When using a punch press holes should be at least 1 material thickness from any edge. OSH Cut offers both blank cutting and bending to make fabricated metal parts. 45° gussets shouldn’t be designed to be more than 4 times material thickness on their flat edge. The profiles for our available punches currently match what is shown above. This is what the k-factor defines. Formed lances and louvers will almost always require specialized tooling so be sure to understand what is available to you before designing the feature. In a part produced using air bending, the metal is placed between a punch and a V-die as shown below: As the press brake forces the punch and the die together, the metal folds where the punch makes contact with the part. If there are internal cutouts that overlap the region where the punch or die meets the metal, it can cause the part to deform, as shown below: Because the material does not make contact with the v-die in the above part, the metal does not bend properly. Rule Of Thumb: Never design a hole smaller than .040” Diameter unless laser cutting. We do not support customizable bend radii, but we selected common and optimal tooling so that if you design around our bend radii, you should be able to have your parts manufactured anywhere. Between two parallel ribs, minimum distance is 10 times material thickness plus the radius of the ribs. This will prevent the need for the operator to flip the part. We do not support customizable bend radii, but we selected common and optimal tooling so that if you design around our bend radii, you should be able to have your parts manufactured anywhere. Wire material should always be the same as the material being welded. What is Bend Allowance and Outside Setback? Minor change in sheet thickness can cause variations in part. The problems most of the manufacturers face while making a sheet metal part is the size of sheet metal. These holes can be small, just enough to get a wire hook through. Always consult a tooling profile chart when developing your part. - 3 - Embosses and Offsets – Emboss and offset dimensions should be to the same side of the material unless the overall height is critical. From the part’s edge, dimples should be at least 4 times material thickness plus the radius of the dimple. If the V-die loses contact with the part, it will not bend properly, if at all. During a bend, the outside of the material stretches, and the inside compresses. What is Bend Allowance and Outside Setback? A hole should be at least the radius of the curl plus material thickness from the curl feature. The arm geometry and throat depth of the spot welder will be a limiting factor. When using a punch press the diameter of a hole should always be equal to that of your tooling and you should never use a tool who’s diameter is less than that of the material’s thickness. When using a punch press the diameter of a hole should always be equal to that of your tooling and you should never use a tool who’s diameter is less than that of the material’s thickness. This also makes you vulnerable to reduced part accuracy. Somewhere in the middle, the metal does neither. Spot welding should be used for joining equally thick co-planar surfaces. You can calculate deductions and offsets yourself, if you'd rather not use CAD. Embossments and offsets should be measured to the same side of material unless it is necessary to hold an outside dimension. For holes, the minimum distance between the hole’s edge is 2 times the material thickness plus the hem’s radius. The "bend stackup" on our press brake looks like the following: Depending on the geometry of your bent part, it could collide with the punch or V-die, die holder, brake, punch holder, or ram during the bend. When you design your part in CAD, you can configure both the bend radius and k-factor to match our manufacturing processes, so that your finished part is as close as possible to the size you intend. There will always be a radius on the bend, as shown below: The bend radius depends on material properties and the size of the V-die gap used to bend the part. Between two extruded holes, distance should be at least 6 times material thickness. For open hems, the bend will lose its roundness when the inside diameter is greater than the material thickness. If you are creating a flat pattern manually, you will either need to compute bend deductions, or use our app to obtain bend deduction and other information for your bend. The part itself only touches the punch on the bend line, and the v … Sheet Metal Fabrication Resources, Blog and Discussion Forum. But again, sheet metal CAD is the best solution to ensure that your part is the correct size. . Recommended Minimum distance between two hole centers in sheet metal design should be equal to sum of hole radius plus two times the sheet thickness. But if the finished size of your part is important, we, At OSH Cut, we publish the bend radius that will be formed using our material and tooling. Gussets are used to strengthen a flange without the need for secondary processes such as welding. For selected bends, our system will report the bend radius, bend allowance, bend deduction, outside setback, and k-factor. Consult and. For example, when you bend a metal part, the outside of the bend has to elongate, and the inside of the bend compresses. Sheet metal design is usually for parts that do not require tight tolerances. To ensure strength the distance between a countersink’s edge and the edge of the material should be 4 times the material thickness. You can use this data to manually modify your flat-pattern if you need to do so. In an air-bending process, exact 90 degree angles are not possible to manufacture. The outside radius of a curl can be no smaller than 2 times the material thickness. The minimum width of a notch is equal to the material thickness and at least .04”. However for typical parts meant to be cost effective and easily produced the following tips should be useful. The diameter of a dimple should be no more than 6 times the material thickness. Because the material will stretch during the bend, the total length of the part - including the radiused area where the bend takes place - will be larger than the original flat pattern defined. When determining the length of a notch it is very important to understand the tooling used to cut the notch. For flat embossments, the maximum depth is equal to the inside radius plus the outside radius. In addition to hanging holes design drainage holes. This prevents bulging along the edge. Distance from outside mold line to the bottom of the cutout should be equal to the minimum flange length prescribed by the air bend force chart. Because Sheet Metal parts are manufactured from a single sheet of metal the part must maintain a uniform wall thickness. Only the truly critical dimensions should be highlighted as such. Below, we walk through how bending works, and how to understand the design rules published in our catalog. For round embossments or ribs, maximum depth is equal to the internal radius of the embossment. These holes will also give you control over how the part is positioned when it is dipped. Air bending is a method of forming sheet metal using a punch and die. Tool designer faces the heat of the manufacturer, and the manufacturer faces the heat of the designer. The minimum depth of a lance should be twice the material thickness and at least .125”, If the lance if formed with standard tooling be sure that the length of the bend is dividable by a standard set of. Sheet metal parts with a minimum of 0.9mm to 20mm in thickness can be manufactured. The minumum flange length is based on the die used to bend. For V embossments the maximum depth is equal to 3 times material thickness. When designing parts for laser cutting one should not make holes smaller than the thickness of the material. But again, sheet metal CAD is the, Channel width and max flange heights in the table below are measured from the. 6. In low carbon steel sheet metal, the minimum radius of a bend should be one-half the material thickness or 0.80 mm At OSH Cut, we publish the bend radius that will be formed using our material and tooling in our material catalog. Design For Manufacturability – Sheet Metal Guidelines Bends For the ease of manufacturing, multiple bends on the same plane should occur in the same direction.