Engineers are under so much pressure to design properly functioning parts that they often fall into the trap of overengineering. The trouble is that overengineering inevitably increases cost and lead time on the machine shop floor. 

At Focused on Machining, we have a simple philosophy about complex parts: “If you need a part machined a certain way, we’re happy to do it for you. But if your materials, features, or tolerances aren’t necessary for the function of the part, we can save you serious time and money.”

We always like to check in with customers during the quoting phase because a conversation gives us a far better understanding of a part than a drawing or model. During these conversations, we often identify cost and time-saving opportunities that can be achieved simply by making a part slightly less complex. 

Today, we’re uncovering some of the common ways customers overengineer parts to help make you aware of these factors during the design phase. 

7 Ways Customers Overengineer Parts 

1. Making the tolerances too tight.

Tolerancing a feature to ​.002” or less indicates to our Denver machine shop that the feature is extremely critical. When a tolerance is that tight, we know that we need to really take our time, slow down our machining processes, and use fresh tools. But going slower and using higher end tools increases the cost and lead time of a part.

If you don’t want to pay more than what’s necessary, and your tolerances don’t have to be quite so tight, consider keeping tolerances at .005” or higher. 

2. Adding complex features that have no functional value.

It’s tempting to design a part that looks really cool. But keep in mind that complex aesthetic features like multifaceted surfaces are almost always challenging to machine. They may even require custom fixturing. Why spend more money than necessary for features that don’t improve part functionality?

3. Making walls too thin.

Since weight reduction is so important for aerospace applications, engineers will often design extremely thin walls to lightweight a part. This practice is especially common when designing the floor of a part.

But thin walls are more likely to warp, so any wall thickness measuring less than .06” creates risk during machining. And if you have exceptionally tight tolerances in addition to thin walls, the part will be even more challenging to make. 

Unless you need extremely thin walls for the function of your part, we recommend keeping them over .06” so that they won’t easily bend or deform. 

4. Asking for a hard anodized finish when regular anodizing is sufficient. 

Hard anodizing a part is risky because the plater adds so much growth to the part that tolerances may become affected. If necessary, we’ll consider dimensional changes that can occur during this process before we begin machining. But if you don’t actually need hard anodizing, regular anodizing is much less likely to impact tolerances. 

5. Selecting materials that are difficult to source. 

Aerospace parts often wind up in such demanding environments that engineers may choose materials that are more high-powered than necessary. But just because a certain material theoretically exists doesn’t mean it’s easy to source. 

If you’re concerned about thermal expansion because a part is going to Jupiter, you may understandably aim for a material with zero thermal expansion. However, if that material isn’t readily available (or available at all in some cases), there are alternatives. You can usually get comparable functionality from a material with very little thermal expansion that has been machined to the precise tolerances the part requires. 

6. Picking a harder material than necessary. 

Stronger materials are inevitably more challenging to machine (they create more wear on the tooling). And yet, engineers will often pick a harder material than necessary—especially when it comes to stainless steel. 

17-4 stainless steel, for example, comes in a series of different tempers based on the strength of the material. 17-4 stainless steel heat treated to condition H900 offers exceptional hardness. But 17-4 stainless steel heat treated to condition H1150 may provide sufficient strength for your application at a lower cost. Any opportunity to minimize heat treating will save you money.

7. Cramming too much data onto one page of a drawing.

This last example is less about overengineering a part itself and more about how dimensions are presented. 

As far as we’re concerned, there’s no such thing as too much information on a drawing. That said, some pages we receive are so packed full of dimensions that they’re actually difficult to decipher

When dealing with complex parts in particular, it’s helpful to break your dimensions into 2-3 pages so that none of your important data gets lost in translation. 

At the end of the day, we’re always willing to machine exactly the parts our customers need. But we also like to help you save time and money whenever we can. Simplifying a complex part is often as simple as having a quick conversation. So don’t be surprised if we reach out to discuss your quote! 

Ready to work together? Request a quote from our Denver machine shop and we’ll respond within 24 hours!