design and optimization

Use of computer to aid in the creation, modification, analysis, or optimization of a design.

You can see that the 3D sheet metal model is a great place to start the manufacturing process, play with ideas and basically help our customers where we can before any sheet metal work has taken place. The next stage once the 3D model has been finished is to create the flat 2D developed blank sheet metal part.

ë

CAD (Computer Aided Design) is used to both design products. It’s effectively a link between the drawing or model and the machining process needed to turn it into a real-life component.

Our Engineering Design Unit, with the help of experienced engineers and graduate men in the field of mechanical designing and manufacturing, is able to implement your layout in the format of Catia, SolidWorks, AutoCAD and CorelDraw software; as well as the design, modeling and reverse engineering of sheet metal working assemblies.

Benefits of our Design Services

As you might expect, not all of our customers are experienced Engineers, able to conceive and detail complex sheet metal designs and assemblies – taking into account wastage, bend loss, distortion and tooling constraints. That’s why we have a team dedicated to providing advice and solutions which are individually tailored to meet the diverse needs of our customers.

Each design is reviewed for viability, cost-effectiveness, and durability before being committed to production. We find that embedding this kind of quality in the process from the very start yields enormous benefits for both ourselves and our customers in terms of cost savings, turnaround times and the quality of the finished goods.

All the compiling of code to drive the laser cutting machine is generated with the click of a mouse and saved automatically to our system server ready for the laser cutting machine setter to call up when they are ready to laser cut the parts.

3D computer software models of sheet metal work components

When we sit down to think about a new sheet metal work project, we inevitably start by creating a 3D model of the component or assembly we are going to manufacture. Creating a 3D model has many advantages for us and our customers when we are planning to manufacture a new design or even an update to a past sheet metal component design. The ability to play with ideas in a software environment without having to commit to cutting or folding any sheet metal materials not only naturally saves time and money but it enables us to investigate different ideas quickly to find an acceptable solution to our customer’s needs and hopefully at a price that is right for both parties. The 3D sheet metal model can be exported and imported back in a STEP or SAT format enabling either our customers or us to initiate the design and update it in a free way until the final design is arrived upon. Some of the advantages of having a 3D model as the starting point for manufacturing are:

 

A) 3D images to aid communication of the design and understanding of the stages of manufacturing

The 3D model can be used to print out 3D views or wire frame images and dimensioned sections for bending, welding fabrication and inspection of the sheet metal work. These images can be used alongside the customers drawings where needed to communicate complex part details to the workshop to reduce the chances of confusion in production.

 

B) Material selection and thickness and its impact on the developed blank size for CNC laser cutting

The selection of the correct material and its thickness from a customized manufacturing database within the Bystronic sheet metal software system enables us to automatically create the developed blank to the correct size. As well as having the ability to create this blank size from the 3D model we can check it against the computer controllers on our Bystronic CNC press brake. We can check that the correct press brake tooling is used and the impact that will have on the developed sheet metal blank cut size and adjust it on the 3D model if necessary. This adjustment may be needed due to the bend radius of exact material specification used and can be physically checked with a sample piece of sheet metal to prove the design accuracy where needed.

 

C) The correct planning of manufacturing tolerances for production processes

The impact of manufacturing tolerance on sheet metal component design is important to achieve the correct fit of parts in the assembly. We have all see drawings with +/- 0.2mm tolerance for a part that is 50mm long and is being CNC sheared, which is fine. When the same drawing border is used for a 2000mm long component which is being CNC punched, bent up and welded we have to talk with the customer and investigate what is really important to them and adjust the 3D model where we can so that the sheet metal work produced will still be functional when it comes to assembly.

 

D) The fit of components such as the correct alignment of fixing holes between 2 or more components in any given assembly

As well as achieving the correct tolerance of sheet metal work from the 3D model the actual simple alignment of parts can be checked. The example show here of a sheet metal box and cover is a classic example. The box and cover may be presented to us as 2 separate 2D drawings on a DXG or DXF file or even a PDF image. By creating a 3D sheet metal model of the 2 parts together with the cover in position on the box we can check out for the customer any problems with the position of holes and the correct clearance for the cover to fit allowing for bend radius and powder coating thickness. If there is a problem at this stage it’s much easier to change the design slightly with the customer than manufacture a box and a lid both to the design drawings but not actually fitting together in assembly.

3D software model of sheet metal box and cover

2D developed sheet metal blanks

Now for us, having BySoft sheet metal software enables us to create a 2D blank (Image B) at the click of a mouse button. Not only is the sheet metal model unfolded correctly taking into account all the material type and sheet thickness details from the 3D model but any possible problems are highlighted at this stage as well. If a cut-out or hole is too close to a bend it will be highlighted in a different color for us so we can take the appropriate action. All the bend lines are also shown on the blank along with the direction and angle of each bend. This data can be useful to automatic setting the CNC press brake back-gauges or operators when they are manually programming the press brakes to bend the sheet metal components. We can also add dimensions and notes to the 2D developed blank drawing to enable inspection if required for important features or bend sizes in addition to the drawing from our customer.

At this stage, the 2D blank is a layout of the sheet metal components to be manufactured and also is machine specific. For us here at LaserSpike, we laser cut the blank with our Bystronic 4.4KW CO2 laser cutting machine.

 

2D developed sheet metal blanks with machine specific tooling

Once we have the developed sheet metal blank we can select which machine or machines we wish to use to manufacture the component. The big advantage of using BySoft software is that the 2D developed blank can be used to tool the part is several ways just with the click of a mouse button. The laser cutting parts can also be profiled with standard cutting “lead-ins” and an automatic tool path calculated to reduce head collision on the laser machine, heat build-up and the shortest route across the sheet to reduce overall laser cutting time in production.

CNC laser sheet metal part program

Sheet metal working laser cutting nests

Once the sheet metal blank has been tooled ready to produce a single part it needs to be applied to a sheet of metal ready for actual manufacture. The optimized pattern of components on the sheet can be automatically calculated by the BySoft software to achieve the best material yield from any given sheet size and quickest cutting path across the sheet to save time. The sheet used can be standard sheets which for us would be a choice of 3 sizes either 2.0M x 1.0M, 2.5M x 1.25M or 3.0M x 1.5M. If the volume is high enough then special sizes can be purchased in some materials to suit a component length and reduce wastage. For example, a sheet metal component blank that is 1.6M long would be wasteful with a 2.0M x 1.0M sheet but would be perfect have we purchased a 1.7M x 1.0M sheet. We can also use up remnants from past work or sheets in unusual shape (like circle, rectangle, etc.) to save buying in fresh material.

Sometimes we have to be able to force the blanks to have a certain orientation on the sheet. This may be ensuring about the grain of material when it comes to bending a component and has been specified by the customer. This is easy and we can control how much automation the software has and how much we need to layout the components by hand if needed to produce the correct nest.

 

The laser cutting next show here (Right Image) are of thin gauge parts that were not bent and had no grain effect on the sheet so we were free to get as many as possible from a sheet of metal with angular freedom of 5 degrees. You can see that the software is able to use a true shape nester to fit parts inside each other’s profile where possible to get the best use of material.

Sheet metal work CNC laser cutting optimized nest

The power of sheet metal design

It is a fact that small changes cut production costs dramatically. Effective sheet metal design should not set out to eliminate welding, but instead, uncover the most cost-effective ways to manufacture a part. The best designs exploit the strengths of the welding process and minimize its weaknesses.

SHEET METAl DESIGN; These three simple words can have a tremendous impact on a company's bottom line. Ideally, effective, innovative, and creative sheet metal design ideas come early in the product design phase, because those ideas will influence the entire project, from the point of manufacturing to the product's end use.

A good designer must know all of the available shop technologies, and it's no secret that one of the most labor-intensive is arc welding. The sheet metal designer should never set out to eliminate welding; after all, arc welding often is the best joining option for the product. The designer's goal should be to maintain design intent while maximizing manufacturing efficiency, and reducing or simplifying welding often can help.

Good sheet metal design should reduce, simplify, and mistake-proof shop floor processes to ensure greater efficiency and, ultimately, dramatic cost reductions. In other words, manufacturing should be as easy as possible. If, say, a new design eliminates welding but makes the bending process incredibly complex, the process is moving backward.

Smart sheet metal design can ease downstream manufacturing. This design gives space for a mechanical locknut, eliminating the need for welding.

Some Ground Rules

One rule of thumb: Bend long parts and weld short. CAM software for the press brake allows the designer to visualize all bends to discover which parts can be produced only by welding. Such software also allows him to try all bending sequence options and, in some cases, discover instances in which he can eliminate welding entirely. The designer must have a solid understanding of bend theory. This knowledge, combined with software, can be a real force in driving down costs.

The more knowledge a designer has, the more questions he asks. For example, it is almost impossible to put a 20mm flange on 8mm thick material; if the flange is required, it will probably be welded. But must the flange be the only 20mm? What is the design intent?

Consider similar circumstances, only now with thinner stock and shorter flanges. Are welded-on, 0.25-in.-high strips there to stiffen the assembly? If so, perhaps a rib or offset would suffice. In this case, the stiffening rib could be formed with an offset tool on the press brake (if the brake has sufficiently high tonnage for the job). Asking just a few questions may eliminate an entire process from manufacturing, and software helps designers quickly run through numerous possibilities.

The Simplicity of Tabs

Determine how parts will be assembled and held in place during welding. Often this requires fixtures, which have associated costs. But using tabs cut by a laser or punch can make a part self-fixturing, or nearly so. Parts also may be designed with tabs so that the parts own weight keeps it together long enough for a spot weld, thus eliminating the need for a fixture.

Tabs also can ensure there is only one way to assemble the part. The Image1 shows tabbing cut with a laser. The assembly still requires a jig, but a welder can fixture it in only one position. Imagine the challenge of a welder trying to obtain an exact center position by using just his eyes for every bracket.

Image1 shows an assembly with two end caps. Notice the different tab and slot positions; on the left, they are both vertical, and on the right one tab is horizontal. This ensures that the part goes together in only one way. Fixturing is simple, and the tabs ensure proper alignment.

 

Image2 shows Another laser cutting technique, stitch cutting, leaves micro tabs on the cut line and allows components to be bent by hand and then welded. This technique allows all components to stay together in the proper orientation and, again, makes for a self-fixturing assembly.

 

A part design should exploit welding's advantages and minimize its disadvantages, and the tab-and-slot approach exemplifies this. It maximizes one of the welding's greatest strengths, the efficient and complete joining of two components; and minimizes the disadvantage of extensive fixturing costs and setup times.

Image1

Image2

Weighing the Fabricating Options

This tabbed assembly still requires a jig, but a welder can fixture it in only one position.

Designers should evaluate finished part requirements. For instance, welding may require grinding, and if grinding is unavoidable, it should be as simple and as easily accessible as possible.

Image3 shows inside and outside welds, and each has advantages and disadvantages. The left part, with outside welds, can be finished from the outside, which leaves a sleek appearance, but the right component may require only minimal finishing if the welds are hidden after final assembly. Although the design on the right may require more material, it doesn't require grinding and so may cost less to produce.

Welding Alternatives

Image3

Image4 shows a bracket affixed inside a cabinet. Part markings, produced by either a laser machine as engraving, can show where to position the bracket. Markings may save some welding setup time, but asking another question could save even more: Do I need a bracket attached, or can it be cut from the base material?

 

As shown in image5, the internal flange could be cut with a laser and formed on a brake with the right tooling. Or, if the flange is short enough, form tools on a punch press could do the job in one setup. Just asking the question—Can this flange be shorter?—may lead to significant cost reductions. Still, these internal flanges would need to be designed with available bending technology in mind. A flange in the middle of a large panel may be too long for a punch press form tool and impractical for press brake tooling to access without deep backgauging.

Here's another question: Is welding the only solution or can mechanical fasteners do the job? Consider the image6, a joint normally welded that is now laser-cut and then joined with a bolt and fastener; the laser cuts the part to the dimension of the nut. The assembler needs only one wrench to tighten the bolt.

Image4

Image5

Smart Design, Simple Manufacturing

Simple designs are not always the most cost-effective to manufacture. In the image7, Design A shows a seemingly simple bracket. Found throughout manufacturing, the design requires two vertical welds to attach the back plate. Its work flow is as follows: laser, press brake, welding, finishing, and then assembly and shipping.

But can welds be eliminated? Will redesign produce other opportunities for improving the part?

Design B shows the bracket redesigned with flat tops to ease bending, but the welds are still there. Design C has no welds and requires five bends, three of which are performed simultaneously. Design D also removes the welds and requires only four bends, and the first two again can be formed at the same time. So in both C and D designs, the brake ram would cycle just three times.

All of these designs take backgauging into account. In Design B, the flat tops of the side flanges can slide against the backgauge pad, but it may not be ideal. The flat tops are somewhat narrow, and the operator can bend only one at a time. A fatigued operator may inadvertently angle the blank slightly just before the brake punch makes contact, perhaps enough to throw the bend out of tolerance and scrap the part. Designs C and D, though, allow the operator to bend the first tabs simultaneously, and they're across the length of the flat part. This makes it difficult for even the most fatigued operator to inadvertently mishandle the part once the tabs are flush against the backgauge.

All options aid manufacturability, and the best choice depends on available machinery and tooling. For instance, the bend sequence for Design C may produce some clearance issues, depending on the distance between the bottom-back and side flanges, the tooling segment widths the operator has available, and perhaps the material's overbending requirements to overcome spring back. Part design requirements also come into play. Those three bottom flanges in Design C may have different structural characteristics than the two-bottom-flange option in Design D.

The designs also have another benefit. They not only reduce or eliminate welding, but they also improve aesthetics and make for safer handling. The vertical sides now have a radius instead of a sharp corner.

Overall, the design alternatives have eliminated welding, improved appearance, provided a flat surface for the press backgauges, and reduced overall weight by adding more holes. Here's the new workflow: laser, press brake, finishing, and then shipping/assembly.

Image6

Image7

gas Options

There are some decisions to be made when it comes to which gas to use when laser cutting the sheet metal work. The common options with laser cutter are nitrogen, oxygen or compressed air as the cutting assist gases. The nitrogen comes directly from a tank where liquid nitrogen is converted to gas, the oxygen directly from banks of bottles and the compressed air from a dedicated air compressor. The choice of gas is dedicated by the types of material being laser cut, the thickness of the material, the final treatment or finish applied to the sheet metal work and the quality of cut required. The software makes the decision which gas to use based on a set of rules but we can change the gas if that is an option that the laser cutting machine can use.

See also:

Metal Art

Design and produce special and decorative metal pieces.

CNC Bending

CNC bending with high accuracy in flange and angle size.

Sheet Metal Fabrication

From low-volume prototype to high-volume production runs.

Tube Laser Cutting

Capacity to slice tubes with rotary option.

Submitting Form...

The server encountered an error.

Form received.