Being a manufacturer of precision sheet metal, CNC machined, and welded parts, we strive to manufacture parts economically and cost effectively. We often receive prints of newly designed parts to manufacture that are poorly designed. Since we provide value-added engineering to all the jobs we manufacture, we will often discuss design changes to the mechanical engineer in order to make the part less expensive and more economical. Here are some design mistakes we often see:
- Too many parts for a single design
- Unnecessary tight tolerances for the part function
- Custom components that are similar to off-the-self components
- Parts that require impossible bends
All of these mistakes drive up the cost to manufacture the parts. As a result, we have created this blog post in order to give you some tips on what to keep in mind when designing metal parts for manfacturability. Design for Manufacturability (DFM) isn’t just designing a good end product, rather it considers the actual manufacturing processes involved and how it will affect the fabrication. DFM helps to reduce manufacturing costs, design parts that are easier to assemble, emphasizes standardization of parts, maximize the use of off-the-shelf components, and save time! The truth is, about 80% of manufacturing costs of a product (including the cost of materials, labor, processes, and assembly) are determined by design decisions, and 20% for production decisions (including process planning or machine tool selection). As a result, we have put together some basic guidelines to keep in mind when designing parts for manufacturability:
- Design common parts. A huge benefit that we always recommend when dealing with multiple assemblies in different product lines, is to design common parts that serve as a multi-functional and multi-use part. This not only saves time, but also saves a lot of money during manufacturing.This allows for increased production quantities which yields better pricing, and allows for flexibility to use on different parts. Not only that, but the time and cost that goes into designing parts can be cumbersome, so having a common part that is versatile is extremely beneficial.
- Design using off-the-shelf components. We have seen numerous companies that will design a custom part to be manufactured, when there is a very similar part that can be purchased off-the-shelf. If the function or purpose of the end product isn’t going to be affected, we absolutely encourage to use off-the-shelf products. It not only saves money from having to manufacture from scratch, but it saves a lot of time since the parts are already made. There’s no need to reinvent the wheel!
- Design with material usage in mind. A huge cost factor can come down to the material (depending on the type and how much material is required). So it is always important to keep in mind standard material stock sizes and how much your part will yield. If you design a part and it only yields one part per sheet/plate with a decent amount of scrap, you have to pay for all the scrap. But if you are able to tweak the design to allow for two or more parts per stock material with hardly any scrap, you just saved money by not having to pay for waste, and you have more parts!
- Design with the least amount of parts per assembly. Depending on the functionality of the assembly, being able to design with the least amount of parts will dramatically reduce the cost. For instance, if you are building an enclosure with four walls, there is no reason to have four panels welded at four corners when you can easily have two L-formed panels welded at two corners. Remember, less is more.
- Design with “more hands = more money” in mind. This may seem strange, but think about it…the more times someone has to handle a part during fabrication, the more costly it’s going to be. For example, if the part requires tight tolerances, the fabricator is going to be spending more time on a part to meet those tolerances than a part with very loose tolerances, which drives up the cost. Or if the part is highly cosmetic and requires more handling to prevent scratches and dings, the part is going to cost more. In addition, the more welding required, the more the price goes up. So an easy way to think of this is to design parts with the thought of the number of hands that need to touch the part, which correlates with the cost to manufacture.
Use these tips and you will see how your parts are better designed for manufacturability and how much money and time you will save. Keep in mind that every design situation is different and not all these tips are applicable. If you have tips that you would like to recommend, feel free to comment below! Thanks or reading along and stay tuned for our next blog post!