The development of a commercial product is a complex costly and time-consuming process. The first stages involve a concept and the way it will look like and operate. The prototypes for them are self-made simple contraptions or look like mockups. The first actual full-fledged product sample is the one manufactured for engineering design process prototype.

The Aim Of Engineering Verification

Prototype engineering verification is the first representation of the design in actual life. It is the first time the product is manufactured the way it should both look and operate. The main purpose of this stage is to determine whether the design as a whole works as desired. Not just the operational parts or not just the visual elements. The design as a whole is tested.

Prototype Engineering For Verification Tests

Despite what is often thought, the manufacturing process for serial production is not yet established at this stage, so the way an engineering prototype is to be processed is variable. It must not necessarily be perfect. The aim is to make the prototype as fast as possible from the materials specified in the design. So, some small design modifications can be made. The ones that won’t change the vital parameters of the product, of course. And here we employ prototype engineering – the art of modifying the design so a prototype can be made faster. And establishing the methods to manufacture it faster.

The Importance Of Getting Help Early

A lot of design companies find themselves in deep waters at this stage. They could cope with previous simpler mock-up models or concept-proof prototypes since those need only perform one or two main functions and imperfectly at that. However, manufacturing a whole full-scale prototype requires a lot of work and specialized equipment. Smaller design companies just won’t have enough manpower and investment capabilities for such a feat. In order to get the product to the market, they employ specialized prototype shops. In order to pass the engineering verification stage, it is extremely important to contact those shops early on. They can give valuable insights into the manufacturability so that when the time for prototype production comes there are less remanufacturing iterations

The Importance Of Standardization

Any manufacturer will tell you that the more standard parts a product has, the better. Standard parts do not require processing, they are easier to come by and replacing them poses fewer difficulties than replacing custom parts. So, you want to make your prototype easier to manufacture? Consider changing some sizes to fit standard parts that can be bought in the market. The first things to look at are fixtures, gears, motors, micro-schemes, valves or pipes, lamps, bearings, sheaves, and buttons.

Engineering Prototype Manufacturing Methods

The difference between an engineering prototype and a latter production sample is that the first one is to be manufactured at a small scale. So, there is no need to invest in hard tooling. Soft ones and standard equipment units are more than enough. This is why the best choices are vacuum urethane casting methods for plastics, CNC machining processes for metal parts and additive manufacturing for complex elements. Add a few manual finishing operations here (take long but are much cheaper and more flexible) and you are all set.

Engineering Verification Tests

Now that you have your prototype, it’s time for the engineering verification tests (EVT). There are lots and lots of different measuring techniques that differ greatly for various industries but the overall sequence is pretty much similar. The EVTs usually consist of three stages.

Basic Functional Tests

These tests establish whether the product carries out the functions that were specified in its design. For example, take a car prototype. It has to, well, move at a certain speed while using a specified amount of fuel. A drone prototype must fly up to a specified height at a specified speed and so on. The tests are carried out in conditions brought as close to real use as possible. If there is an opportunity, the prototypes are manufactured as a small batch and given to volunteers for testing to get feedback. This is the most important test because if the “car” doesn’t drive, there is no point in manufacturing it.

Parametric Measurements

We have established that the prototype carries out its basic functions. After that, it is useful to analyze it while it works. Reliability and safety factors are assessed here. For example, the car may move and fast but what if it gets so hot it’s impossible to sit inside? Parametric measurements are aimed at detecting such inconsistencies. The prototype is usually fixed with tons of different sensors that measure temperature, pressure, voltage, noise, etc. The tests are thus conducted in laboratory conditions. They determine whether the product is fit for the whole range of different requirements imposed by the industry and country regulations.

Specification Verification

This type of verification actually starts while the product is being assembled. The designers check if all the parts fit the assembly well, they analyze whether there are obsolete parts or if somewhere an element should be united or split into an assembly. The manufacturer analyzes how technologically efficient the product and all its parts are, he checks all the tolerances and surface finish requirements and makes notes of unwanted requirements that make the manufacturing process larger but do not bring much efficiency to the product.

What Happens After The Tests?

After the tests have been completed all the obtained notes remarks and characteristics are analyzed by the designers and they decide, what should be changed in the design to make it better. After that, the whole product is reworked by the designers and another engineering prototype is manufactured. It is tested again and its overall efficiency is assessed and compared to the previous prototype. Some problems are solved and new ones are detected since the design has been changed. I would like to note that no product design is perfect and any well-made product undergoes at least a couple of prototype iterations because you can’t predict everything and every manufacturing operation hones your design considerably. After a number of iterations (3-5), the product is ready for the next stage: Design Verification Tests.