There are many types of prototypes, or proof-of-concept models. These terms can often blend together and cause confusion.
Proof of Concept
A proof of concept is the earliest version of a new product. This could be a new invention or an update to an existing product. The focus here is on functionality, not looks. Proof of concept models often lack visual appeal. Many invention prototypes start at this stage.
As the name suggests, this model shows the concept of the proposed product. It requires little or no investment in tools and is a great candidate for 3D printing.
3D modeling simplifies design visualization.
3-D modeling, along with computerized analysis, helps visualize the concept with clarity. You can simulate almost any physical condition. Spending a few hours on computerized analysis at this stage is wise. Detailed analysis can wait for later stages.
You should test the proof of concept’s performance. While analysis is helpful, it cannot replace actual testing. Even testing a single model can provide valuable insights.
Pre-Production Prototype
People often confuse this term with proof-of-concept models. I see the pre-production prototype as the next step after the proof of concept. This phase is a big step toward the final product. It also includes important manufacturing details. Consider expected sales volume and production methods. These include molding, machining, or casting. Expected quantities matter a lot. For larger volumes, use molding and casting in the design.
At this point, cut spending on any tooling, whether temporary or permanent. The design is still too flexible.
Testing of various types is essential. This might include performance tests to check how the product works in real life. You might also conduct approximate certification tests in-house to save time and money.
HALT Testing
HALT testing—highly accelerated life testing—can provide significant advantages in this context. This testing gradually increases stress until a failure occurs, showing design weak points. You should also complete FMEA analysis (failure modes and effects analysis).
Production Prototype
Now, some investment in non-permanent tooling may be wise. You should finalize decisions on part manufacturing. Use expected production methods for parts where possible and run short production tests. Formal certification tests are appropriate at this stage. Be ready to make changes.
Full Production
The design is now finalized. Permanent tooling is in place, and everyone involved needs to reflect on the product. Every department should contribute before starting production runs.
At this point, we must complete several tasks:
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Are all design changes finished? Are they long-term solutions or quick fixes?
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Are all part changes to print complete?
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Are part evaluations finished for form, fit, and function?
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Is all documentation complete?
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Is the packaging design finalized, and are the vendors ready?
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Are all bills of materials complete?
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Are all outsourced parts in stock?
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Has the organization trained all assembly personnel?
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Are all quality control documents and inspection criteria ready?
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Are vendors qualified? Is there more than one vendor for each part to avoid the risks of single sourcing?
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Are material sources approved?
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Have off-the-shelf prices been set?
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Have we addressed export legalities and controls?
This list is not exhaustive. Make sure everyone is comfortable before starting production. You have a lot of detailed work ahead.
Norman T. Neher, P.E.
Analytical Engineering Services, Inc.
Elko New Market, MN
www.aesmn.org