Sheet metals have become precious assets to many manufacturing industries. However, designing sheet metals for fabrication might be a challenging task for most manufacturers. Designing them according to the client’s preferences requires great care and time.
Therefore, as a sheet metal designer, you must have remarkable design strategies along with clear goals. For better concept building, this article explains the best tips and tricks to design sheet metals effectively. By following these tips, you’ll surely be able to make the process smoother and more efficient.
Let’s dive straight into the article!
What are Sheet Metal Design Tips for Better Fabrication?
After a deep analysis of sheet metal designing results, some standards are set to attain perfect designs of sheet metals for fabrication. The following are the 12 best tips you should follow:
1. Consider the Hole Size
The hole size and position play a vital role when designing sheet metal products. The ideal way to estimate the hole size is to keep its diameter almost equal to or more than the thickness of the sheet metal material. Doing so prevents your tools from breakage or damage.
Whereas to create tiny holes, small punches are utilized, which can easily break while working. Moreover, designing consistent diameters of holes on a sheet metal surface helps to accelerate the production rate as there will be no need to change the tools frequently during the operation.
Additionally, ensure you always locate the holes away from the curls and maintain a fine distance between each hole.
2. Bend Radius
If you want to create more strain for the sheet metal workpiece, make sure it has a smaller bend radius. The cracks can be formed as soon as the fatigue point is exceeded.
In the case of ductile metals, the bend radius equal to the thickness of sheet metal would be enough. In contrast, other brittle metals like aluminium can work better if larger bend radii are made.
3. Maintain Uniform Bend Orientation
Bending the sheet metal leads to different required geometries of fabricated parts. It is preferred to locate the bends in the same place and direction. By manufacturing uniform bends, you can eliminate the requirement to reorient the products, which helps in both saving time and money. Hence, to boost the production process, you should consider this tip.
Hems play a significant role in making safe edges on workpieces by folding the edges of sheet metal. Usually, an open or tear-dropped hem is considered preferable due to its lower risk of breakage or fracture. On the other hand, you should avoid designing flat hems.
Moreover, you need to look at some parameters while designing open and tear-dropped hems:
● Open Hems
When dealing with open hems, it is crucial to create an inner diameter equal to or greater than the sheet metal thickness. Plus, make sure you keep the length of the folded portion four times the measurement of thickness.
● Tear-dropped Hems
The same ratios go with the tear-dropped hems. Yet, you need to aim for an opening measurement minimum of ¼ of the workpiece thickness.
5. Tabs and Notches
Measurement ratios are the key to perfect sheet metal designs. You must follow exact measurements, whether it’s a hem or tabs and notches. Like, in the case of tabs, their length should not exceed five times their width. However, their minimum width should be twice the thickness of sheet metal.
When it comes to notches, they should also be wide according to the thickness of the material. Further, the distance between each notch should be ⅛. In addition, if you’re thinking of designing the notches and tabs near a bend. The estimated ratio of their location is at least three times the thickness of sheet metal.
6. Tooling Choice
The tools you select for manufacturing your products are responsible for deciding the shape of the parts. For instance, there is a tool known as a conventional press-brake tool that helps produce straight-line bends on fabricated sheet metal workpieces.
In addition, you can adopt features including round embosses, countersinks, bridge lances, extrusions, and many others by using different tools.
7. Limit The Use of Tight Tolerances
If you want to design the sheet metal more efficiently, you need to limit the use of tight tolerances. Building the prototypes with unnecessary tight tolerances only results in high-cost finished parts production. Therefore, you should only include the features that impact your project positively without making it expensive.
Common examples of tolerance callouts are holes, radii, distances, and diameters.
8. Simplify the Folds
Undoubtedly, the more complex designs you’ll go for, the more money you have to spend. Therefore, make simple angles while creating bends if you want to save your budget. Apart from that, a perfect sheet metal design has the best folds whose radius is at least equal to the thickness of the metal material.
Furthermore, if you’re using thick parts, make sure you avoid creating small bends, as they are less accurate.
Offsets are also a kind of bends having a Z shape. You can mainly use these bends on clamps and brackets. The suggestion regarding offsets is to keep all the bend radii similar. Besides this, keep the parallel planes double the thickness of the material.
10. Flange Width
Another tip for designing an ideal sheet metal is to maintain the width of the flange. Typically, flanges are internal and external ridges responsible for strengthening the parts. The best ratio for the flange width is at least four times the sheet metal thickness. Designing a lower flange width may result in marks on the surface.
11. Sheet Metal Gauge
A sheet metal gauge is also one of the critical sheet metal design tips to consider. You need to choose the thickness of the sheet metal according to the part’s geometry. Generally, the bend angle of thick materials is limited and sharp bends are unsuitable for press brakes or punch presses.
You may also experience microscopic cracks on the sheet metal in this situation. Ultimately, the part becomes brittle and can be easily broken. Thus, it may cost you more. In a nutshell, you should prefer thin metals to avoid the complications of thick sheet metals.
Knowing the names of the sheet metal materials is not enough to choose the one. Instead, you need to have a more profound knowledge of the critical characteristics of these metals.
- Look for the tensile strength of the metal to determine the maximum load it can bear without breakage.
- You should choose a malleable metal according to the demand of your project.
- Hardness is another factor you must select wisely, as it is the ability to resist hard pressing.
- Temperature is one of the most important considerations as it impacts the property of the sheet metal. For instance, changes in electrical resistance occur due to temperature.
- Elongation ratio lets you know about the ratio of the elongated sample material.
Mistakes You Should Avoid When Designing the Sheet Metal Products
The following mistakes act as a hurdle for you when designing the sheet metal products for fabrication:
● Not Including Hardware Specs
When starting the operation, it is necessary to include the details of hardware specifications in the CAD file. Without the addition of them, the lead time for fabrication may extend. However, you must decide the type of hardware tools required for your project, such as nuts, bolts, studs, etc.
● Choosing the Wrong Finish
Finishes serve for the protection of products and enhancement of the material’s appearance. There are a few finishes that offer both services at a time. Yet, some only focus on looks, such as aesthetic finishes. Powder coatings offer a little protection from corrosion, while skill screening is meant to only add text or images without any protection.
On the other hand, chemical conversion finishes provide good protection for the parts by altering the properties of surfaces. You may consider galvanizing as the best finishing option.
● Designing Unrealistic Weld Requirements
Make sure that your welding requirements are always realistic. You can never weld inside a closed box, so weld on the outer surface of the part. Also, you need to consider the thickness of the metal before welding. The minimum material thickness required for welding is almost 1.016mm.
● Failing to Consider U-Channel Strength
If you aim for U-Channel designs of sheet metal, your key focus should be on the material strength and bending capabilities. Maintaining a 2:1 width-to-height ratio for designing U channels is the best practice.
● Non-skilled Workers
Manufacturing industries are suggested to hire experienced and professional workers to deal with the sheet metal fabrication process to achieve the desired goals. No doubt, you need to pay high to skilled workers, but it is better to compromise on the cost than your project.
Finally, keeping all the tips mentioned above and mistakes in your mind will help you to achieve perfect fabrication results without any errors. Along with these tips and tricks, a skilled manufacturer can guide you more about sheet metal designs. This combo will drastically impact the fabrication process of your products.