Guidelines to be followed by Contractors and Subcontractors for fast and accurate process of sheet metal design

With the booming services and the tools and techniques that are getting advanced day-by-day the engineering fields are working on providing more qualitative work and with high end finishing to it. The service here is all about sheet metal design services. By testing multiple types of metals that are available at an affordable cost, the fabricators of the sheet metals do demand for accurate fabrication drawings. This is possible only when the team follows the decided and defined software along with different factors that are required in the entire process of sheet metal modeling.

The entire process of sheet metal designing is to facilitate the overall and efficient production of the work cycles with an improved way that is better for the contractors and suppliers. Further, for the business optimisation and acceleration of the manufacturing process it is mandatory that the sheet metal designs compliant with the industrial standards. The team of engineers in the manufacturing industries find the entire process of metal and sheet metal designing challenging. The only reason behind it is the compliance rules and the quality of the standards that needs to be considered for delivering the tasks with faster and quicker deadlines.

Moving further, to achieve the control over the cost and to reduce the design iterations the engineers deliver the work with high-quality sheet metal parts along with the shop drawings of manufacturing and fabrication by using various platforms of CAD. The CAD drafters are the one who pertain wide and expert knowledge in the designing and drafting of solid works modelling that are set as per the guidelines of DFM. Further, it helps the sheet metal contractors and the manufacturing companies to reduce the costing in ECOs.

Now let us proceed further and check for complete guidelines that need to be followed mandatory in the process of sheet metal design service or if at all the contractors and the subcontractors are proceeding and opting for Outsourcing Sheet Metal Design Services.



  • To make the work easy and convenient for the manufacturing unit, the process of multiple bends should be occuring in the same direction.
  • Make sure to avoid the large part of sheet metals when the entire process is with small bent flanges.
  • If the carbon sheet metal is low, then the minimum radius of the bend should be accurately one-half of the overall material thickness. Or in other words, it should be 0.80mm (0.03 inch), whichever is larger.
  • The bends that are specified in as angles can be adjusted at plus or minus to one-half degree to the location that is adjacent to the bends.


  • The lowest radius in this is almost two times as that of material thickness. This is related to an opening to a minimum of thickness of one material.
  • The distance between the two i.e the curl and the edge of the hole is basically the radius of the curl and in that adding is material thickness.
  • The minimum distance between the curl and the internal bend should be approx six times the thickness of the material along with the radius of the curl.


  • The maximum diameter in the dimples should be six times the thickness of the materials along with the on-half maximum depth of the inside diameter.
  • The smallest dimple distance from a hole is three times the material thickness of the radius of the dimple.
  • The smallest distance between the dimple and the edge should be four times the thickness of the material along with the inner radius of it.
  • The minimum distance between dimples from a bend is two times the material thickness along with the inner radius of the dimple and the radius of the bend.
  • The minimum distance between one dimple to another dimple is four times the thickness of the material and in addition to the radius of each dimple.


  • It is necessary to hold the outside dimension of the material as the embossments and the offsets should be measured from the same side.
  • For the round embossments or the ribs, the maximum depth is as equal as the internal radius of the embossment.
  • If the embossment is flat, then the maximum depth is equal to the inner radius and in addition it is with the outside radius.
  • The material thickness is equal to 3 times the maximum depth for the V embossments.
  • The embossments should be having at least 3 times the material thickness as that from the hole's edge.
  • Between the two parallel ribs, the least distance should be 10 times the thickness of the material along with the radius of the ribs.

Extruded Holes:

  • In between two extruded holes, the minimum distance should be at least 6 times as that of the thickness of the material.
  • From the edge to the extruded holes, the minimum distance should be 3 times the material thickness.
  • From bend to extruded holes, the distance should be 3 times the material thickness plus the radius of the bend.


  • The height of the bent flange is directly related to the thickness of the material, along with bend radius, and the length of the bend. This is upto the lowest height.
  • The minimum width of the bend relief is the one that is of material thickness or 1.50 mm (0.06 inch), whichever is the greater.


Without the need of the secondary process of welding, gussets can be used to strengthen the flange. As gussets will always be requiring custom tooling there is a need to follow some basic guidelines that can give assistance. Before this process it is necessary to consult with the factory's brake press department to learn what process of bend will be used in the equipment.

  • 45° gussets should not be designed to be more than having 4 times the material thickness on the flat edge.
  • In the stage of holes, the difference between the hole's edge and the gusset must be at least 8 times the material thickness.


Hems is the stage that is used to create folds in the sheet metal in order to stiffen the edges and create a safe edge to the touch.

  • The inside diameter in the tear drop hems should be equal to the thickness of the material.
  • If the hems are open, the bend will loose its roundness, and that is in the inside diameter which is greater than the material thickness.
  • For holes, the distance between the hole's edge is 2 times the material thickness and adding to it is the hem's radius.
  • For bends, the minimum distance between the inner edge of the bend along with the outside of the hem must be 5 times the thickness of the materials. Adding to it is the bend radius and hem radius.


  • The minimum diameter of the hole should be equal to the thickness of the material. Either it can be in the size of 1.00 mm (0.04 inch), whichever is the greater.
  • The lowest interval in the middle of holes is directly proportional to the size and the shape of the feature of hole as well as the thickness of the material.
  • The minimum spacing that the edge of the hole should be three times the thickness of the material along with the form radius.
  • The distance the edge of the hole should be from a bend and that too it is two times the materials thickness and addition to it the bend radius.
  • The lowest interval between a hole and the edge of the material is directly proportional to the size and the shape of the materials thickness and the size of the hole.

Lances and Louvers:

The formed lances and louvers will be always requiring a tool that is specialized in it and hence it is necessary to understand what option is available and have an detailed understanding before proceeding with the designing feature.

  • The minimum depth of the lance should be double the thickness of the material and at least 125"
  • If the formation of the lance is accomplished with standard tooling, then be rest assured that the length of the bend is divisible by the standard process of sectionalized tooling.
  • From a bend, the thickness of the material should be at least 3 times and adding to it must have the bend radius. However the actual sizing is often way greater than this and is considered by the tooling profiles.

Notches and Reliefs:

  • The width of the notch is equal to the thickness of the material and at least .04". This is getting negated if the blank is getting from the edge by the process of laser system and that in the case of minimum and has only the kerf of the laser.
  • It is necessary to understand the tool that is used to cut the notch as this is very important to determine the length of the notch.
  • The minimum distance from the bend is 3 times the material length plus the bend radius.
  • In the process of fabrication with the punch press the minimal spacing between the two notches must be at least twice the thickness and at least 125".


  • The process of welding done with the hands should have the restriction to the gauges. The thickness for the same is almost thicker than 20 gauge.
  • Spot welding must be used for joining equally and with that the thickness should be at the coplanar surfaces. The arm geometry and throat depth of a spot welder will be to the limited factor.
  • Try to add wires if possible so as to remove the need of the welder. The welded joints must be designed as tight as possible so that the tolerance is possible.
  • The material of the wire should be the same every time for the materials that are being welded.


  • The sharp edges and the corners will be typically receiving in the count of double and as much as the plating material. It is because of the current density of the areas for which the process is taken into consideration.
  • Try and check for the possibility to tap and thread it after the work of plating. Neither be in an assumption that the material will be growing upto 4 times the typical plating thickness, and will be compensating the pitch and the depth accordingly.
  • Avoid the areas that are difficult to get in reach such as recessed areas.
  • As the parts are going to be hung up from the hook and dipped, it is beneficial to get design of hanging holes to that part rather than leaving it blank to the plater. These holes can be in the sizes as per the wire hook through which the work will be completed. This will also be giving the control of the wire that are dipped along with the position of the wires and hook.
  • Adding to the hanging holes the design for the drainage holes too are considered. It is because knowing the part of the orientation that is from the hanging holes it is necessary to make sure that the parts are cleaned easily post the process of plating.

Moving further, in this entire process of Sheet Metal Design service there are some more guidelines that are playing a vital role and the name for the same are mentioned below.

  • Ribs
  • Semi-Pierced Hole
  • Slots
  • Tabs
  • Counterbores
  • Countersinks


Till now reading this blog, you would have understood that how tedious is the entire process of the Sheet Metal Design is all about. Thus, to know more about it you can contact us by simply filling the form and letting us know your requirements. Based on that the team will be reverting back to you within 24 business hours with the details.

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