Finishing Considerations for Contract Manufacturing Services

“Finishing” may sound straightforward, but it actually encompasses a wide range of options and considerations that can seriously impact a manufacturing project’s success. 

As part of our contract manufacturing services, Polyhistor offers a comprehensive range of finishing services in-house and via a network of trusted vendors. Before you make a choice, let’s dive into some options and which factors you should consider.

Surface Finishing


Though a standard as-machined finish is always an option, we offer part sanding, polishing, and more for customers with specific requirements. These finishes impact the quality and appearance of a material’s surface. While many of these solutions may be employed for aesthetic purposes alone—such as giving a grand piano hinge an eye-catching engine-turned finish—they can also enhance functionality. For instance, we may sand a part’s surface prior to painting to ensure excellent paint adhesion.

Because a part’s surface finish directly impacts its quality, durability, and performance, selecting the right finishing process is critical. Polyhistor provides finishing to your specifications, whether you need a coarse-grit surface finish with a high Ra (roughness average) or a fine-grit, ultra-polished finish with a low Ra.

In addition to our standard, as-machined (“as-milled) finishes, you can ask the Polyhistor team about:

  • Sanding
  • Vibratory (“tumble”) finishing
  • Brush finishing
  • Bead blast finishing
  • Polishing
  • Prototype Wet Painting 


Our CNC machine shop provides coatings in-house as well as through our well vetted supply chain for anodizing, chromate plating, wet painting, powder coating, and more. These secondary processes add a protective or aesthetic layer to your part’s surface—a factor that could impact your part’s tolerances, depending on the thickness of the coating and how tightly your part’s features are toleranced. If you need assistance modifying your part design to account for coating, our in-house engineers are available to assist.

Coatings can also extend your lead time, so you should talk to our team and discuss your options before adding a specific coating callout to your part’s print. If one coating has a five-week lead time but another similar coating will take less than one week, we’ll notify you of the options and allow you to determine what’s best for your job.

Ask your Polyhistor representative about:

  • Powder coating
  • Cadmium plating
  • Chromium plating
  • Nickel plating
  • Zinc plating
  • Alodining
  • Anodizing
  • Black oxide on steel as well as stainless steel
  • Passivation

Selecting the Best Finishing Solution for Your Part

Before committing to a particular finish or coating, consider these questions:

  • Are you primarily finishing for aesthetic reasons?
  • Are you finishing for functionality?
  • How flexible is your timeline?
  • What’s your budget?
  • What are the part’s durability requirements?

Your answers to these questions will influence the choice of finishing service and your total cost and lead time. For example, if you request black nickel when black anodize would suffice, you could be looking at a 50x cost increase just for the finishing! On the other hand, if your parts require conductivity, the black nickel coating may be exactly what you need—and worth every penny to you.

Also, remember that some finishes are very similar in composition and can accomplish the same protective or aesthetic goals, and may have shorter lead times. The Polyhistor Team will let you know if there are any substitutions available that can help.

We’ll Help You Make Your Final Finishing Decisions

To select the right finishing process for your particular project, you need a manufacturing partner who understands the intricacies of each option. For example, a seemingly simple prep step, such as masking for wet paint, can be time-consuming and costly. If you talk to our team upfront, however, we can save you from any surprises and ensure your contract manufacturing services run smoothly from start to, well, finish.

Get Superior Finishing Services with Polyhistor

Our comprehensive portfolio of contract manufacturing services was developed to bring your vision to life, from individual parts and prototypes to full-scale product development services and high-volume production machining. 

Choosing the right finishing solution involves balancing the functionality and aesthetics you desire with your preferred cost and lead time. With Polyhistor on your side, you’ll be well-equipped to make the decision that best aligns with your project’s goals and constraints. At Polyhistor, we go the extra mile to offer finishing and coating services that make your products truly perfect.

Get a quote to work with us!