Prototyping 6

Prototyping on a new level with Crealeon | 2022

Today it is hard to surprise professionals with terms such as “prototyping” or “rapid prototyping.
However, each speaker puts its own meaning into them. Often it is the exact understanding of the meaning of these words that determines the quality of the order. Meanwhile, the meldmaker’s practice shows that in most cases customers who have a need in prototyping don’t understand what they should get and why. The author of the article offers to understand the meaning of these terms and find out what advantages prototyping technology provides.

Let's agree on concepts

According to open sources of information, the word “prototype” comes from the Greek for “first” and “impression. The first part of the term is clear: indeed, a prototype is an early example or model built to test a concept, design, or process. The second part, “impression,” is precisely the essence for which everything is conceived. Already at the stage of selecting the type of prototyping, the questions of exactly why and what the prototype will be used for should be answered. Today, prototyping can be used almost everywhere: for quick realization of ideas and fantasies, as a unique type of production, as fully functional models and samples, for various applications.
But there are some subtleties. We are all used to thinking that “prototyping” is a derivative of the words “prototyping” or even “rapid prototyping”. However, it’s worth separating these concepts.

A prototype is first of all some physical object-sample, model, mockup. Prototyping – the process of creating (using certain methods or technologies) some physical object for specific purposes. The last indication is not insignificant, because that is where the crux of the matter lies. “Rapid prototyping” is a literal translation of the English phrase rapid prototyping into Russian, denoting a certain prototyping technology. There is a misconception, introduced by sellers of this specialized technology, that rapid prototyping is carried out exclusively on 3D-printers. It is just as wrong to agree with this as it is to believe that the widespread SLA (stereolithography) technology is printing. It must be understood that rapid prototyping is not exclusively printing on “magic” printers, but only a kind of prototyping process based on the transfer of material from the reservoir on the plane of model creation in the working area of the installation.

3D printing. Let’s dwell on available today and the most popular technologies of prototyping.
Perhaps today it is difficult to identify a single technology that could be, as before, namely 5-7 years ago, the prevailing and flawless, such as was or seemed by virtue of its prevalence all the same SLA. Technological advances have spawned a host of alternative ways to obtain prototypes.

SLA. The advantages of stereolithography: high accuracy and speed; excellent external surface quality and high level of detail models.
Various mechanical and optical properties of modern materials used expand the scope of SLA. The technology is ideal for:
obtaining transparent (no yellowish cloudy color) parts;
design verification prior to production start-up of tooling and tools to avoid design errors;
production of complex parts and parts that cannot be produced otherwise;
production of visual prototypes for demonstration and demonstrations;
obtaining prototypes for functional testing;
Creating reference materials (models) for tooling production control and master models for silicone molding.

FDM. Object is formed by layering molten filament of fusible working material (plastic, wax). The working material is fed into an extrusion head, which extrudes a thin filament of melted material onto a cooled platform, thus forming a current layer of the object being developed.

Laser powder sintering (SLS – Selective Laser Sintering). The laser beam sequentially sinter the powder material along the contour of the individual layer. Rapid prototyping of metal and ceramic parts takes place precisely with this method. One advantage is the high performance properties of the materials used.

Multi-Jet Modeling (MJM). The printer has different modes of model making. By combining these modes and using each of them depending on the need, the grown object at the output has an unprecedented quality of detail, which fully meets the specified parameters and expectations of the user.
The smooth outer surfaces of the wax models reduce material consumption and labor intensity at the machining stage.
The model material for these machines is acrylic photopolymer and the support material is wax. The size of the working chamber, for example, of the ProJet DP 3000 printer is quite sufficient to model relatively large (up to 30 cm) objects.
All of these technologies can be classified as 3D printing.

According to open sources of information, the word “prototype” comes from the Greek for “first” and “impression. The first part of the term is clear: indeed, a prototype is an early example or model built to test a concept, design, or process. The second part, “impression,” is precisely the essence for which everything is conceived. Already at the stage of selecting the type of prototyping, the questions of exactly why and what the prototype will be used for should be answered. Today, prototyping can be used almost everywhere: for quick realization of ideas and fantasies, as a unique type of production, as fully functional models and samples, for various applications.
But there are some subtleties. We are all used to thinking that “prototyping” is a derivative of the words “prototyping” or even “rapid prototyping”. However, it’s worth separating these concepts.

A prototype is first of all some physical object-sample, model, mockup. Prototyping – the process of creating (using certain methods or technologies) some physical object for specific purposes. The last indication is not insignificant, because that is where the crux of the matter lies. “Rapid prototyping” is a literal translation of the English phrase rapid prototyping into Russian, denoting a certain prototyping technology. There is a misconception, introduced by sellers of this specialized technology, that rapid prototyping is carried out exclusively on 3D-printers. It is just as wrong to agree with this as it is to believe that the widespread SLA (stereolithography) technology is printing. It must be understood that rapid prototyping is not exclusively printing on “magic” printers, but only a kind of prototyping process based on the transfer of material from the reservoir on the plane of model creation in the working area of the installation.

3D printing. Let’s dwell on available today and the most popular technologies of prototyping.
Perhaps today it is difficult to identify a single technology that could be, as before, namely 5-7 years ago, the prevailing and flawless, such as was or seemed by virtue of its prevalence all the same SLA. Technological advances have spawned a host of alternative ways to obtain prototypes.

SLA. The advantages of stereolithography: high accuracy and speed; excellent external surface quality and high level of detail models.
Various mechanical and optical properties of modern materials used expand the scope of SLA. The technology is ideal for:
obtaining transparent (no yellowish cloudy color) parts;
design verification prior to production start-up of tooling and tools to avoid design errors;
production of complex parts and parts that cannot be produced otherwise;
production of visual prototypes for demonstration and demonstrations;
obtaining prototypes for functional testing;
Creating reference materials (models) for tooling production control and master models for silicone molding.

FDM. Object is formed by layering molten filament of fusible working material (plastic, wax). The working material is fed into an extrusion head, which extrudes a thin filament of melted material onto a cooled platform, thus forming a current layer of the object being developed.

Laser powder sintering (SLS – Selective Laser Sintering). The laser beam sequentially sinter the powder material along the contour of the individual layer. Rapid prototyping of metal and ceramic parts takes place precisely with this method. One advantage is the high performance properties of the materials used.

Multi-Jet Modeling (MJM). The printer has different modes of model making. By combining these modes and using each of them depending on the need, the grown object at the output has an unprecedented quality of detail, which fully meets the specified parameters and expectations of the user.
The smooth outer surfaces of the wax models reduce material consumption and labor intensity at the machining stage.
The model material for these machines is acrylic photopolymer and the support material is wax. The size of the working chamber, for example, of the ProJet DP 3000 printer is quite sufficient to model relatively large (up to 30 cm) objects.
All of these technologies can be classified as 3D printing.

prototype 4
prototype 3
prototype 2
prototype

Prototypes from blanks

Another way to obtain prototypes is to process workpieces on CNC 3-axis machining centers by milling. This type of prototyping today makes it possible to produce parts with maximum dimensions up to 1800.600. 500 mm, which is not available in most cases on 3D printers. But the most important difference or, we can say, a reasonable addition is that for milling a solid billet (e.g. ABS block) is used, which guarantees product characteristics comparable with the properties of a plastic part made by injection molding technology.
The cost of milling is usually much lower compared to other product manufacturing technologies. And the precision of modern machining centers makes it possible to make precision parts.
Flexible machine settings and operator experience make it possible to produce thin-walled parts, including double-sided machining. Large parts are produced using sequential joining of smaller parts. Proper machining design and precision allow even parts with so-called undercuts to be produced.
It is now possible to produce prototypes from a variety of materials suitable for
MDF, polystyrene, styrofoam, polished and black ABS, polycarbonate, acrylic, polyamide-6/66, POM, PP, PE, Teflon, polyphenylene, polyphenylene sulfide, polyphenylene oxide, polyetherketone, polyetherimide, polyamidimide, polyestersulfone and other plastics.

However, nowadays it is not enough to have only the usual plastics at our disposal – when creating structural elements and layouts, the use of such materials as:

  • metals (aluminum alloys, stainless steel, zinc, brass, copper, bronze);
  • zirconium and zirconium ceramics. The properties of this metal are ideal for jewelry and watch parts. Zirconium alloys have excellent characteristics – they are lightweight, very strong and hypoallergenic;
    Ceramics with different chemical and physical properties (high specific electrical resistance, high compressive strength, resistance to oxidizing environments, and high resistance to fire);
  • quartz glass.
    In some cases, if it is necessary to obtain a functional layout or prototype with a high quality external surface, additional aerosol coating is used, including its popular type, such as soft-touch. It is enough to specify the desired color of the product according to the RAL catalog and the surface texture (gloss, semi-gloss, matte) when placing an order.

To paint the parts, we use aerosol paints with a high degree of adhesion to polymeric materials and wear resistance.

Casting in silicone molds.

The task of obtaining a small series of parts (up to 100 pieces) from plastics is solved by using polyurethane resin casting into silicone molds under vacuum. The key advantages of this technology are low time consumption and moderate cost in comparison with aluminum or metal molds manufacturing.

Silicone injection molding is the ideal solution for the following tasks:
– obtaining prototypes and marketing models;
– manufacturing of small batches of parts;
– Short lead times;
– obtaining parts of very high quality or with the possibility of finishing the surface;
– production of large and small parts weighing from a few grams to several kilograms;
– possibility of a wide choice of colors and textures (e.g., roughness);
– guarantee of moderate unit cost.

Wide range of polyurethane resins similar in their physical and mechanical properties to thermoplastics allows to get high quality models while casting into silicon molds. Such materials as ABS, polyamide, polypropylene, polyethylene, transparent polycarbonate and acrylic, rubbers and elastomers are also used.
In conclusion, it should be noted that only a comprehensive and balanced approach to prototyping can solve a lot of problems at the stages of its creation and use and guarantee that those tasks for which the prototype was conceived will be implemented in full.