The product you designed has a cost. This cost is very much determined by how you have designed it. If we look at the cost of a product, we can divide it into two major categories: Manufacturing and Assembly.
And all costs come down to: Labor force, material, energy, and down payment of a large machine. Material and energy are usually set to be low for most engineered parts, and if you buy materials in bulk you will get them even cheaper. Buying machine time is somewhat medium, but can also be very low if you are manufacturing parts at a high volume. Labor force on the other hand is usually a high cost, that doesn’t get much cheaper with more scale.
But just like you can optimize for the perfect stress distribution in a part, you can also optimize for the cost of your product!
Optimizing for low cost
When you are designing a product, you can optimize for a low price. It is called either Design for Assembly (DFA) or Design for Manufacturing (DFM). With DFM you focus on making your parts more manufacturable and therefore each individual part cheaper, that will not be the scope of this article.
DFA on the other hand is designing for easier assemble of your product. Often times easier assembly means fewer parts!
The part count of an assembly is one of the simplest and yet most effective measures for how easy a product will be to assemble.
Therefore, you should always strive to get to the lowest possible part count!
But how should I change my design?
The easiest way to start optimizing a design to lower the part count is to apply simple design guidelines. This design guideline you can use as a best practice checklist and will help you optimize for assembly. The list we have collected for you are the following:
Avoid entanglement: Springs can easily entangle and it would take extra time for the worker to assembly the product if he have to untangle springs from a bin. If the spring has closed ends, it would be less likely to entangle.
Avoid deep pockets: You might have tried to insert a bolt and drop it into a deep pocket where it can be hard to hit the hole. If the pocket is less deep than the shaft of the bolt, you won’t have this problem.
Self-aligning parts: Also in the case of the deep pocket. You can make a chamfer at the bottom of the pocket to make the part self-align.
Self-locating parts: Sometimes you might have to hold several parts in place while reaching for the allen key, this can be hard and you wish you had a third hand. By designing you part to have a mating geometry and be self-locating, you make this a lot easier.
Avoid reorientating the assembly: If you constantly have to reorient the assembly to add the next part, you will spending a lot of time reorienting the part. If the part is heavy, this will increase the burden a lot. Design the parts so they can be assembled from one side or at least from fewer sides.
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