At Heinz Engineering, we pride ourselves on our dedication to customer satisfaction. We’ll build parts to print if that’s what you need—but we always want you to know when there are opportunities to improve quality, cost, and lead time. 

Requesting finishing operations like heat-treating or anodizing midway through the machining process is one common way that customers inadvertently drive up prices and extend timelines. Finishing a part after machining is complete is the standard recommendation—and for good reason. 

Risks of Finishing Parts Midway Through Machining 

If you need your part finished in the middle of machining operations, we’ll gladly make it happen. But before you call out this request, make sure you’re aware of the risks involved:

Finishing parts

  • Thread warpage. Processes like heat-treating can alter material properties such as hardness, strength, and ductility. If we know we’ll heat-treat apart after machining, we can account for these changes. However, heat-treating mid-process can render parts with threads unusable. The property changes can cause threads to warp once they return to machining.
  • Tool breakage. The machining tools that cut raw material most effectively are more likely to break when used on hardened, heat-treated material. If you elect to have your part heat-treated mid-process, we’ll have to account for specialized tooling that can handle the change in material hardness post-heat-treating. 
  • Long lead times. When we send a part off for finishing mid-process, we break down its setup, then reset it once the part returns for further machining operations. We can avoid this process (tightening up lead times in the process) if we machine the part to completion before sending it out for finishing. 
  • Damaged finish. Machining a part after finishing it with anodize or chemical film coating can damage the finish, compromising benefits like corrosion resistance and potentially limiting the part’s lifespan. 

Best Practices for Finishing Parts 

When requesting a quote for a part that needs finishing, be sure to provide as much information as possible. If we know why you’re requesting a finishing operation midway through machining, we may be able to offer an alternate solution to minimize risks while still getting you the exact part you need. 

If, for instance, your goal is to make a hard material even harder, we may suggest heat-treating the material—in raw bar stock form or smaller pieces—before machining begins. This approach can be effective for materials like aluminum, but it’s not ideal for materials like Inconel that are already exceptionally hard and likely to break machining tools. 

In most cases, the optimal time to heat-treat a part or perform other finishing operations is after machining. Finishing a part that’s fully machined cuts machining cycle time, reduces tooling costs, and ultimately produces a better quality part.

If, for any reason, you wish to have your part finished midway through machining, we simply ask that you call out this request on your drawing so that we can plan for it accordingly. 

When you need machining for defense and aerospace applications, trust Heinz Engineering to deliver. Request a quote today and get a response in 24 hours.