5 Stages of Mold Creationkprokop
Current requirements towards techniques of creating metal components in molding process concern mainly the product quality and production time. It is important to remember that when launching a new element production, the evaluation of construction solutions, its ergonomics and visual features are essential. In order to do this, a prototype is created, it helps to eliminate any possible errors and make amendments in the design phase. Traditional process of model production is rather lengthy and expensive. With the use of rapid prototyping techniques and a 3D Printer working in Fused Filament Fabrication technology we are able to meet presented requirements.
Stage 1. Obtaining 3D-CAD Model
To obtain a 3D-CAD Model we can use CAD software for instance SOLIDWORKS and design an item from scratch. Another way is to use reverse engineering and generating points cloud with the use of 3D Scanner. It is also a good idea to use a CT scan or magnetic resonance, usually used in medicine for prosthetics geometry or implants. However, data generated with the aid of 3D Scanner, CT or magnetic resonance cannot be used directly. It is necessary to process it in CAD software in order to generate a proper lump.
Stage 2: Saving the model in STL format.
Saving the model in the STL format causes triangulation of lump’s external surface. What we get is a ‘shell’ of the model, built of triangles with specific parameters which are decisive factors when it comes to the quality of the print.
Stage 3: Opening the STL file in SOFTSHAPER software.
This gives us the possibility of dividing the model into layers of specific thickness, setting the percentage of model thickness, generating support structures, setting and rescaling the model in the working space and generating work paths. The print accuracy depends on the layers’ thickness, which can be regulated.
Stage 4: 3D Printing.
3D Printing time depends on a few parameters: layer’s height, wall thickness of the model, filling, printing speed, the type and number of supports. Presented rotor model was created in 6 hours filled up in 35% in VSHAPER SINGLE printer with Build Volume 270x270x200mm. Printing parameters were carefully chosen in order to obtain a durable model in shortest time possible.
The model is created in one operation and one setting and there’s no need to prepare supports, which in case of conventional method is more complicated and time-consuming. Molds created in FFF method are characterized by visible layers on the external surface. Proper post processing in the form of grinding, sandblasting or bathing in acetone fumes enables surface polishing.
Stage 5: Creating sand mold of bentonite mass.
We use the mold created by us to produce sand mold of bentonite mass. The use of molds made in Fused Filament Fabrication technology in the process of disposable sand molds creation makes it easier to generate a good quality usable mold or prototype. When designing mold in FFF method a few factors need to be taken into consideration: wall thickness of the model, signs on vertical walls, which are difficult to make, and model dimensions confined by the size of working space of the printer.
Using the FFF method to produce the mold we’ve been able to reduce the time of physical model production to eight hours ( with printing time of 6 hours).