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Correctly “prepare” the prototype. Case Prototyping Technologies

How to choose the right technology for the prototype case of any device, what headaches do developers have, when the virtual 3D model becomes physical, and how to treat them? See instructions. The main thing here is to understand that a specific prototyping technology is designed to solve a specific problem.

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“A prototype is a working model, a prototype of a device, mechanism, or part.” So writes Wikipedia about this term.

What is the prototype for? To check the properties of the device, mechanism or parts. There are several properties to check.


... and there is much more that can be verified by making a prototype.

In other words, a prototype is needed at the moment when the virtual model enters the physical world. In this transition, problems that cannot be identified in the development environment necessarily emerge. They need to be caught before the process of preparing the hull or product for mass production begins.

There are a lot of prototyping technologies. We take the most common for the manufacture of plastic cases (as the most popular). By the way, the further to the end of the list, the closer this technology is to mass production.

Prototyping technologies: to each his own

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1. Handmade mock-ups made of plasticine, foam plastic, clay and other easily processed materials. Such models will allow to conditionally evaluate the appearance of the product, not more. Well, maybe even check the ergonomics. Production time - days (one, two, etc.), the cost is insignificant.

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2. Printing with plastic thread (FDM) - layering of molten plastic on the pad. So far, such details need to be seriously refined before use (plus painting and finishing). Similar prototypes, as well as mockups, also do not solve complex problems, but allow us to evaluate design and ergonomics. Often with their help you can understand the real weight of the product, some properties of stiffness. Production time - hours (except for manual processing). Cost - a penny.

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3. Laser sintering, printing with photopolymer (SLA, SLS) . The prototype of the case, made by such technologies, is already more or less complete: it allows you to check not only the design and ergonomics, but also to organize the initial study of the collection of the product, as well as to some extent assess the rigidity.

The advantage of the technology is the ability to print multibody prototypes, i.e. immediately the whole product. Details require minimal grinding, are suitable for painting and are indistinguishable from the real from afar. You can even make them transparent.

But the problem of such prototypes lies in the fragility and rigidity - it is easy to break a printed case, and it may not work to check, for example, whether the button is well pressed. In short, the real picture made by SLA or SLS technology will not give.

Production time - a few hours, the price tag - a few thousand rubles.

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4. Milling of plastic and metal. Such technologies will allow you to get close to the properties of the serial product. In fact, this technology begins with the “life test” of a design or a device case. After all, the material of the prototype has the same properties as the serial case - stiffness, torsion, springiness, etc. And such a prototype can close all questions on the collection, design, weight, destruction, behavior in real "street" conditions.

The situation with leak tightness testing is worse - after all, a rubber gasket cannot be made by milling. With transparency is also not easy.

Production time is several days, equipment for multi-axis milling cannot be called common, that is, the contractor must also be searched (but if necessary, write, we will give contacts). The price tag is tens of thousands of rubles.

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The photo shows the milled case in comparison with the case made by the FDM method.

5. Polyurethane casting in silicone molds is an excellent technology that answers almost all the questions on the physical properties of the body: rubber, transparent parts, exact correspondence with plastics in terms of rigidity, springiness, color, texture. Casting in silicone allows you to check even the properties of the future device, as its "behavior" in the cold or heat.

This technology, although simple, is expensive. There are few contractors. Even less of those who do neatly and beautifully. The term is several days, the cost is tens of thousands of rubles.

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6. Plastic molding under pressure in easily machined forms . In fact, this is already the circulation production, as close as possible to the series. But its cost is sometimes 2-3 times cheaper than production with the manufacture of full-fledged equipment, and even faster in terms of time.

The equipment for such casting is made of soft metals with the help of milling and manual finishing. But the material (molten plastic) is fed under pressure, as in normal production. You can get a prototype, identical to a serial product for all properties, and make small (thousands of pieces) series of enclosures or parts. Cost - hundreds of thousands of rubles, the term - a few weeks.
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Choosing the right technology.

So, you need to answer the question: “Why do I need a prototype?” And choose the technology depending on the answer. For example:

- The prototype is needed to check only the design → Choose a three-dimensional printing (3D).

- It is important to check the “collectability” of the instrument case with real components (for example, a board) → It is better to use 3D printing or plastic milling.

- We test the product in real conditions with real iron. Or do you want to show the device to the client, investor or take it to the exhibition → Choose a milling or casting of polyurethane.

- If the task is even more difficult (for example, it is important how, how many times it is pressed and when the button breaks) → Only polyurethane or plastic injection molding.

ATTENTION ! All technologies require varying degrees of development of the original model and design. And, if the first three of the above are sufficiently tolerant of errors in the design, then starting with milling in preparing the documentation you will need experience of the designer, and when choosing the latest technology in the list (6) - the designer with experience in preparing molded products.

If you have questions, send information on your product (project), we will advise the production technology and / or contractor (of course, already checked many times).

Source: https://habr.com/ru/post/437950/