Guide to Avoiding Sheet Metal Part Design Mistakes
During the designing phase of sheet metal parts, engineers tend to face several challenges. This affects how the quote of the model eventually turns out. It is important to avoid these mistakes in your models. Here is further insight into some of the common design mistakes done and how to remedy them.
Positioning Sheet Metal Part Features Closely to Bend Lines
One common design mistake is placing sheet metal part features too close to a bend. Examples of such features include tabs and holes. At Creatingway, we recommend you follow the 4T rule when positioning such features. This means you should keep the features at a minimum of 4× the material’s thickness away from the bend lines. For instance, give your feature at least 0.200 inches if the quote specifies to use 0.050 inches of aluminum. This allowance avoids the occurrence of awkward deformity on the sheet metal parts.
Inclusion of Hardware Specs Details in The CAD File
Do not forget to include all details of the hardware specs in the CAD file. It avoids the development of longer lead ties during sheet metal fabrication. These specs can range from the specific type of self-clinching nut to the flush-head stud. Therefore, you will get exactly what you want on the part. Also, it saves time and the trouble of making decisions on your behalf.
Picking The Wrong Type of Sheet Metal for The Task
Selecting the right sheet metal is very important. When designing, consider the type of environment the metal part will face once complete. It would only be a waste if you quoted hundreds of parts made from unfinished steel whose installation is a salty, marine environment. Thus, avoid future customer complaints when the parts purchased begin corroding. Here are some factors to consider when selecting the right metal sheet.
- Protection from corrosion
- Cosmetic look
- Conductivity for electrical applications
- Mechanical features such as ductility, tensile strength, yield strength
- Manufacturability
- Wear resistance
Selecting The Wrong Finishing
Sheet metal part finishes mainly serve two roles. First, they protect the part. secondly, they make the part look even better. Aesthetic finishes emphasize o the looks rather than corrosion prevention. One great example is silk screening that adds images and texts o apart without increasing protection. However, finishes like powder coating offer some degree of protection unless scratched.
Chemical conversion finishes aim to protect your sheet metal part. The reaction alters the properties of the surface layer making it more corrosion resistant. Examples of such chemical processes are galvanizing and galavanting. It adds a protective zinc coating on the sheet metal. However, it is not advisable to weld galvanized steel as it produces dangerous fumes.
Anodizing makes the metallic color of your part pop out while also protecting it. Lastly is the chromate conversion option. This finishing process gives your part improved electrical conductivity. It also gives a great primer layer for painting later. Carefully consider these available options. Find out if it will suit the part you are designing.
Having Unrealistic Weld Design Requirements
At Creatingway, we recommend that you design the welds to be done on the outside of the sheet metal part. This sounds more realistic than trying to weld inside a closed box. The torch should be able to access the seam for welding to occur. Also, metal melts when subjected to high temperatures. Thus, there is a minimum metal thickness of 0.040 inches to avoid creating a molten metal mess. Finally, it is important to note the need for welding in the quote. Either use the welding nomenclature or function. Do not box corners as an indication of welding.
Think About the U-Channel Strength
Engineers commonly fail to consider the u-channel strength based on material strength. This determines the ease of bendability. We recommend you keep a 2:1 width-to-height ratio for u- channel design. This works well with the available broader tooling. In case you need narrower channels for the sheet metal part, consider a riveted or welded assembly.
Getting The Perfect Perpendicular Sheet Metal Part Corners
Did you know, when bending sheet metal part in a press brake, it does not form a perfect 90-degree angle? The tool instead forms a rounded tip that has a radius at the bend. To get the bend radius, we measure the length of the bent area and divide it by two. This figure defines the tool used in making the bend. You have to quote this value if the size of the curve is important. The common default bend radius is 0.030 inches. One amazing tip in reducing cost is sticking to radius for all the bends. Unless you want to get fancy and have a part with multiple radii. Take a look at these common mistakes in sheet metal part designing to get the most out of your design.
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