Functional Injection-Molded Prototypes
In the product development process,
molders must react quickly and accurately to engineering changes, and
delays in the schedule can make a difference between success and
failure. Functional prototypes gives the product designer or the
original equipment manufacturer a best-results approach to proving
product integrity and providing answers to critical questions needed
for a production path.
No matter what industry you serve, the market for injection molding often demands expedited launch schedules, lower overall development costs and products that do not compromise the intended design or material. In the product development process, molders must react quickly and accurately to engineering changes, and delays in the schedule can make a difference between success and failure. The need for functional prototyping has never been greater.
But what is functional prototyping? Simply put, it’s a prototype process where the same tool that provides the prototype for testing and validation can be used for the initial production run. In some low-volume scenarios one tool is used for the entire production run.
The functional prototype process gives the product designer or the original equipment manufacturer a best-results approach to proving product integrity and providing answers to critical questions needed for a production path.
Benefits of Functional Prototyping
There are several benefits to functional prototyping, including:
- Speed to launch: A functional prototype allows product engineers to prove concepts and support initial production launch with a short, cost-effective path using real-time and real-life validation data.
- No compromises: When building a functional prototype mold in the hybrid process—using all of the machining technologies available and the methodology of inserting a variety of soft, hard and heat-treated hybrid materials—you will create a mold that not only supports initial fast-path-to-market requirements and low- or moderate-volume needs, but there will also be no compromise to the customer’s original product design or geometry. Tolerances in the range of +/-0.0025 over one inch are achieved.
- A bridge to manufacturing: Depending on the material and geometry of the functional prototype tooling, any one prototype tool is fabricated using a hybrid concept of tool manufacturing. Functional prototypes of this nature can yield between 50 and 200,000 shots, which bridges prototyping to production and can cover either the initial or complete production volume.
- Complexity at lower cost: Functional prototyping is ideal for highly detailed, tight-tolerance molded products and assemblies, and affords customers the opportunity to lower overall project cost. Customers are able to stretch program budgets further and reduce the amount of manufacturing processes it takes to bring a product to market successfully and economically.
Traditional Choices are Limited
Functional
prototyping offers distinct advantages when you need to move straight
to production, while traditional options have their shortcomings for
various reasons. SLA, for example, the process of stereolithography,
cannot be used. It is strictly for producing three dimensional “feel
and touch” models, essentially a mock-up or visual aid for presenting a
product concept or idea. Another option is a prototype that is machined
from a solid. However, this often does not represent final product
intent. In many cases, the machine-from solid-plastic-part concept
requires numerous concessions to your product design.
Another traditional process would be the use of the SLA or machine-created model representing the actual prototype part required in the urethane-casted rubber mold process. Urethane cast molds will yield a short-life product yield for injection molded parts, but with a large sacrifice to the eventual tolerance repeatability and in many cases, resin limitations.
The term “rapid tooling” is not a process, patented software or a special machine. It is merely a loose term used to describe tooling created in the fastest path available. If you are to use rapid tooling for your mold process, you will be required to make numerous design concessions so your product or math data can be created in a CNC cutter path program.
A True Functional Prototype
When
considering a functional prototype, be sure that the prototype meets
all the aspects and requirements needed on the project. If absolute
speed and the fastest turnaround are imperative, there is a prototype
process out there that will give just that. But the word “functional”
needs to be dropped from the inquiry.
A true functional prototype:
- Does not limit design or require compromises with the tool fabrication. It also should not require sacrifices in the final resin or allow for loose tolerances.
- Uses the exact product geometry and math data, 100 percent. The only design changes should come as part of design-for manufacturability recommendations that will stabilize the product during post-mold shrinkage, thereby optimizing the dimensional tolerance and repeatability of the manufacturing process.
- Can be made out of any engineering grade thermoplastic in any color. The mold fabrication process must take into consideration the material and its tolerance requirements.
- Must be manufactured in a molding process that is controlled and monitored, with documented repeatability and part-to part, lot-to-lot dimensional stability.
- Brings products to market quickly and does not leave a customer stranded on the dock when a product needs go beyond the initial prototype phase.
- Supports initial product validation requirements and initial product fulfillment. When we think “prototype” we think of something that’s produced fast. It’s also nice to realize the prototype, in a functional sense, can connect with production and support initial or complete production needs. A prototype that will be there initially and quickly without any compromise to product math data or dimensional tolerancing and is based on the quantity or total volume required may be the only tool needed for a component or product.
