Modelporex, s.l. has reached an agreement to collaborate with the Enterprise FABROCAM in order to offer their clients a PROTOTYPED service.
MANUFACTURING CAPABILITIES FOR RAPID PROTOTYPING TECHNOLOGIES
1.- STEREOLITHOGRAPHE (SLA)
The Stereolithography is one of the ionizing techniques in the market. This technique triggers a process of polymerization through a UV laser incidence of a few milliwatts. The points targeted by the laser beam solidify, creating a consistent layer in the cutting shape that corresponds to each height. The 2D geometry of every cut or layer leads the movement of two galvanometric mirrors that reflect the laser beam onto the work surface. When the layer finishes, a piston goes down mechanically, allowing it to be covered by the new liquid layer with the desired thickness to continue the process.
This solidification is being carried out through layers until the piece is completed. Afterwards, a post-cured stage is required for the piece to be totally solidified. This treatment is carried out in an oven under ultraviolet light.
2.- POLYJET TECHNOLOGY
The materials used to manufacture the prototypes through the Polyjet Technology are photosensitive resins that are placed in liquid state and hardened thanks to the UV rays, in other words, they cure with solar light. The dimensional precision (0,1mm) and the quality in the details and the superficial final stage are optimal when the machine works with a layer height of 16 micron. This way the obtained pieces are totally valid for commercial presentations, exhibitions, etc.
Nowadays, the possibility of working with two materials simultaneously has been developed with this technology.
3. SLS, LASER SINTERING
Through this technology and from CAD 3D files functional prototypes are manufactured in Polyamide material. The sintering system uses a laser to unite some particles of plastic powder so it constitutes a piece through the powder. Like all prototyped technologies, it works with layers, in this case, powder layers
The powder itself that has not been united is used as a support for the cantilevered parts of the design. This technology has the possibility to work on several materials and even to incorporate fibre charges to provide it with more resistance to the prototypes.
The superficial final stage is rough but the prototypes functionality is good. The colour of the pieces is white. The prototypes cost is cut down meaningfully since some sets can be sent to be carried out in a single cask.
4. FDM TECHNOLOGY
For enterprises that want to produce their own fast prototypes but do not wish to carry out a big economic investment in a RAPID PROTOTYPING system, FDM turns out to be a good alternative.
Like in the previous systems, the parting element is a tri-dimensional CAD model, which is chosen by horizontal drafts and whose sections are transferred to the “Rapid Prototyping” machine where the piece will be manufactured.
The thermo-plastic material, in a semi-smelted state, is extruded through a nozzle and placed layer by layer until the model is completed. The header of the machine is fed through thread-shaped material. In the header, this material is heated up to 1º C above the smelting temperature.
When the material is placed by the header, it puts a determined pressure on itself, achieving, on the one hand, that it gets immediately welded with the previous layer and, on the other hand, the desired layer thickness.
The used temperatures in this process range from 70º C to 140º C.
The material is found initially in thread bobbins of 1.8 mm (0.07”) of diameter and in two kinds: a) the material of the piece itself, and b) the support, material of the same nature but more fragile. The existence of the support in the prototype manufacturing is essential in this kind of technology. The amount involved in every one of the materials varies depending on the shape and orientation of the piece during its conformation, avoiding breaking and deforming.
5.- HIGH SPEED MACHINING
The characteristics of plastic injection moulding are as different as the components, which makes it difficult to discuss global solutions for all the companies in the industry. The precisions, superficial final stages, etc.. are very different between a moulding destined to the manufacturing of telephone connectors or medical equipment and another destined to be a car bumper.
However, the industry feels the constant pressure of delivery dates every day becoming shorter and shorter and with quality requirements that 5 years ago were inconceivable.
The High Speed Machining consists of the optimization of the machining with the existing possibilities limited by the piece/ material to mechanise and tools- machines (CAD/CAM-CNC) available. This could imply mechanising at cutting speeds from 5 to 10 times higher than the ones that are used in a conventional way “for every material”.
The High Speed Machining tends to substitute the coating of great depths at low cutting speed for more and faster coating with less depth in the cut, obtaining a considerable increase of removed shavings (material volume per time unit).
High cutting speeds and high advances decrease the cutting power due to shavings that are becoming smaller and smaller.
6. VACUUM CASTING SYSTEM (VCS)
Vacuum Casting is obtained through the smelting of the silicone via a master model that once extracted allows us to have a soft moulding over which we can carry out the vacuum casting of the desired material.
A master model is carefully prepared, carried out usually by SLA or SLS, to obtain the junction plane and to assure a good final stage of the surfaces. Afterwards, the silicone smelting takes place around the master moulding.
Once the silicone has been hardened, the moulding is cut according to the junction plane and the master model is extracted, leaving a cavity to smelt copies. Due to the silicone flexibility, the little sloped cuts do not raise big problems when it comes to separating the moulding parts.
To carry out the copies, bi-composed polyurethanes are used. To avoid the apparition of air bubbles, the moulding is carried out in a vacuum so it is possible to produce high quality pieces at a higher speed. A wide range of polyurethanes with different characteristics exists, ideal for the manufacturing of the prototypes that can be used for functional testing under several conditions, such as mechanical and thermal testing or environmental-chemical testing.
The smelting of other materials can also be possible, for instance silicone. However, due to the viscosity of the silicone, this technique differs from the traditional smelting process. For silicone smelting different presses are used that allow the insertion of the silicone inside the silicone moulding. The silicone moulding is not too expensive and it offers great exactitude in the final stage, so the pieces manufactured with this technique are ideal to carry out the prototypes and small series.
7.-RIM – Reaction Injection Moulding
RIM (Reaction Injection Moulding) is a technique to produce plastic pieces through injection with low pressure of thermo-stable resins in moulds.
Different moulds can be used, however, resin moulds are the most frequently used ones.
Moulds are mainly carried out for small series built from a manufactured model through fast prototyped methods.
If you are in need of tangible prototypes essentially functional or assembling, this might be the technology that you need. The pieces that can be obtained can be of large dimensions, resistant, they can be tested, mechanised, they can receive subsequent treatments (sand blasting, depostitions, metallic treatments,…) and paint. We emphasise the flexibility of the obtained models, although not in a multi-directional way.
Polyurethane resins, with their different formulations, allow us to obtain a variety of plastics, from elastomers to polycarbonates.