Electroplating specifications (“specs”) refer to written sets of standards and recommendations for the specific plating process being completed. Specifications are extremely important, as they allow engineers to clearly and directly communicate their expectations to the plater.
How Specs Are Used
As an example, a common black oxide spec is MIL-DTL-13924. This specification outlines bath requirements such as temperature and supplemental oil treatments, and also lists the materials that may be processed using this spec. Within the spec are classifications for the different materials that further specify the process.
When choosing a spec, engineers must be as precise as possible and include every part of the spec, not just the reference number.
For example, the zinc plating spec ASTM-B633 not only defines the zinc plating process but also includes a service condition that indicates thickness of plating and a finish type that details the chromate conversion requirements and color. The chart below shows the various thickness and chromate conversions that this spec can have.
Putting this information into practice, an engineer has designed his part to have a tolerance of .0002 inches and needs the finished color to be all black. His spec should then read:
ASTM B633 Type II, SC 1, color: Black.
In order for the part to be processed as the engineer has specified, all of this information must be included with the engineering print and supplied to the plater.
Sampling and Testing Requirements
Specs also often include sampling and testing requirements to ensure the quality of the finished process.
When passivating a part using ASTM A967, for instance, a spec may include six possible tests that can be run after passivation to ensure the part meets the standard. The engineer can choose which test to perform by reading the spec and calling upon one of the following practices:
- Practice A. Water immersion test
- Practice B. High humidity test
- Practice C. Salt spray test
- Practice D. Copper sulfate test
- Practice E. Potassium ferricyanide-nitric acid test
- Practice F. Free iron test
Which test the engineer chooses depends on the materials being passivated, the costs involved, and the availability of the tests at the plating facility.
Using Specs to Choose a Plater
Specifications provide a way for engineers to communicate their expectations to the plater using a clear and universal standard. First, though, engineers need to become familiar with the specs they use and carefully include all the information conveyed in the specification description.
When choosing a plater for your next project, be sure to provide engineering prints along with the specifications. Don’t be afraid to ask about their capabilities and which tests they perform to make sure that the finished parts will meet your requirements. A good plater will work with their clients to ensure that everyone understands the process at hand and that the desired results are achievable.
Having a solid understanding of specifications for your unique needs will ensure that all of your electroplating jobs get completed safely, efficiently, and on-time.