Many factors are involved in precision machining—the design, raw materials, machines, and methodology are just a few. One factor that’s extremely important but sometimes overlooked is a customer’s intent.
At Reata Engineering, we care deeply about your intent for a part because, ultimately, it helps ensure the success of your project. If your part doesn’t look, feel, fit, or function as intended, it’s a bad part, and that’s unacceptable to us.
We want to make it easy for you to articulate your intent so we can be aligned on your project, and the best time to begin communicating this critical information is during the design stage.
7 Tips for Precision Machining Designs
Let’s explore seven tips to help you convey intent to your contract manufacturing partner.
1. Provide both a 3D model and 2D print
3D models have wholly reinvented how manufacturing companies make parts for customers. Sending your precision machine shop a 3D model is an excellent way to convey the physical geometries of your part and enable easy programming.
However, 3D models alone aren’t enough because they have one major drawback—a lack of detailed information. We recommend also providing a 2D print, which includes the specifications manufacturers need to make parts that look and function as intended.
When you provide both files up front, we clearly understand your intent from the start and can avoid back and forth down the line.
2. Identify critical dimensions
When preparing your 2D print to submit along with your RFQ, please remember to identify critical dimensions—at the very minimum.
We prefer to receive fully dimensioned prints, but we understand that sometimes that’s not feasible. We will, however, need to see the dimensions for any critical features called out.
Our holistic approach to manufacturing success begins with reviewing designs and ensuring we have the necessary information to make your parts. Including critical dimensions on your print helps convey your intent and empowers us to make your parts correctly.
3. Use GD&T standards and symbols
One way to make your part designs clear and comprehensive is to use Geometric Dimensioning and Tolerancing (GD&T) rules and symbols as much as possible.
GD&T is a set of standards used to communicate design intent and part function. Designs incorporating GD&T tend to be highly accurate because the precisely articulated system of language minimizes ambiguity between customers and manufacturers.
At Reata Engineering, we recognize that not all engineers are comfortable using GD&T and have some excellent resources to help you become more familiar with it.
4. Clarify dowel pin holes
Dowel pin holes indicate the accurate location and alignment of components. While very small, these features are critical in ensuring that your parts fit together correctly. We encourage our customers to note “for dowel pins” where appropriate on their designs.
Tolerances for dowel pin holes are another important consideration. Sometimes, we see designs that note a standard block tolerance for a dowel pin hole, which is far too big. A standard block tolerance is typically 20x larger in tolerance than what is ideal for a dowel pin hole, so be sure to call out specific tolerances for these features.
5. Make your true position on threads larger than 0.010″
Going back to GD&T, true position—the “total permissible variation that a feature can have from its true position”—can help convey design intent by indicating the field where a feature should be located.
We recommend making the true position on threads larger than 0.010″. If the true position is any smaller, the parts costs to manufacturer will increase.
6. Indicate hole depth or thread depth—not both
Contract manufacturing companies spend quite a bit of time talking to customers about the hole sizes in their precision machined parts. Because precision machine shops and customers often use different systems to measure holes, discrepancies can easily occur.
To avoid confusion, we advise customers to indicate only the hole depth or the thread depth—not both. Typically, customers will call out thread depth, and the contract manufacturer will determine how deep to make the hole.
7. Provide anodizing information
If your parts will be anodized, you’ll need to provide specific instructions in your print.
Do any holes need to be masked to prevent anodize buildup? Be sure to call that out clearly. Are there specific surfaces that must have a superior cosmetic finish? Let us know, so we can ensure that the anodizer racks your parts accordingly.
It’s also important to indicate whether the dimensions noted on your print apply before or after anodizing so that we can meet your specifications.
Reata Engineering Is Here to Support You
As a customer-focused company, we are here to help you with your precision machining designs. If you’re struggling to articulate your design intent, please don’t hesitate to contact us.
We have the capabilities and resources to see your product from concept to distribution. We are also experts in Design for Manufacturing (DFM) and Design for Assembly (DFA) and can share best practices for optimizing your design so you save time and money.
Let’s work together on your next precision machining project. Request a quote today!