What is the peculiarity of 3D models for a 3D printer?
Programs for printing a 3D printer use models in the .stl format. The surfaces of such models consist of triangles or XYZ coordinates of the three points of each triangle, so the model can be represented as text – text format. In binary format, such triangles are polygons.
Stl models can be developed directly in programs and editors for 3D printing. And it is possible to export CAD-format models created in various CAD-systems to STL format.
All the most famous CAD systems have this ability and do it well. What if, on the contrary, the stl model, for example, scanned using a 3D scanner, is converted to a CAD format, i.e. vector format.
A model that consisted of many triangles will consist of mathematical figures – cylinders, planes, radius fillets, etc. In this case, some small elements of the part may be lost.
The Stl model is not suitable for NC machines, in most cases, solid-state models are used there, but for 3D printing, it fits perfectly.
Modeling for 3D printing is a special magic that is not available to every 3D designer. In this process, there are many nuances and features that need to be considered when preparing the model for printing.
What does every 3D designer need to know about modeling for 3D printing?
So that a 3D printer can “eat” your 3D model and not rebel, you need to properly prepare it, to competently prepare a 3D model for 3D printing.
Printing is limited by print resolution. It is not possible to print small parts that are smaller than the size of the nozzle. In addition, a problem arises when the previous layer does not have time to cool down and a new one is placed on top of it. The geometry of the object suffers from this. This problem is partially solved by forced cooling of the previous layer by airflow.
The size and geometry of the object. If the model has overhanging elements, then support structures must be printed. Supports are difficult to remove if they are printed with the same material as the main model. This spoils the not-so-perfect surface.
It is also necessary that the model has a flat base, otherwise, it will detach from the surface of the desktop. If the base of the model is non-flat or very small in size, then the model is printed on a special substrate – raft. Removing the raft also spoils the surface.
The maximum dimensions of the print field. There is a print working field. Model exceeding the dimensions of the maximum size of the print field at a time does not print. There is only one way out of this situation – you need to cut the model, print in pieces and glue the printed pieces.
Possibility to print mechanisms assembly. Assembly mechanisms, for example, a bolt-on in which a nut is screwed, is really possible, but not for FDM technology, not exactly of that accuracy. The nut and bolt fuse together. It is much easier to print the same bolt and nut separately.
Although, there are models of cars with spinning wheels and a whistle with a ball inside, which is broken off with a screwdriver.
Printed models do not need processing. The surface of the printed model is not at all perfect: burrs, ribbing, sagging. To smooth the surface, mechanical (sanding, burr cutting) and / or chemical treatment (a bath with a solvent) is used.
Non-waste technology. Unlike a milling cutter, there is significantly less waste. After all, an object is created not by removing the excess from a single piece of material, but by building.
Nevertheless, there will still be some waste:
Plastic tends to leak out of the nozzle during downtime
The percentage of defects can be very high (especially at the beginning of the path of a 3D printer)
When the coil of plastic ends, there remains a tail that is not enough to print anything useful
Supports, substrates, skirts, which are then cut off from the printed model
The printer is cheap or vice versa expensive. Of course, assembling a printer yourself is much cheaper. But this option is suitable for those who have time. Because part of the parts will have to be ordered from abroad.
Printers are assembled by hand, in particular, because of this they are expensive. But value is falling and will continue to fall. Again, everyone has different opportunities and for someone million dollars is not money.
Everything is simple! Plug and print. This is the biggest misconception. Whatever the printer for 150 thousand rubles or for 20 thousand, you still have to “dance with a tambourine.” If the printer is calibrated, you will have to select the slicer settings. For a good print, you need to gain experience. It took me about six months to do this, along with the constant completion of my printer.
On 3D printing, it is possible to make a good business. It will be a disappointment for those who are chasing money. There will be no huge profit because there is not much demand.
Competing with large-scale production does not make sense. It is much easier and cheaper to buy going to the store than to print it. Printing is suitable for personalized objects (for example, a mug with your name), small-scale production (if the entire circulation will cost less than the mold for casting), prototyping (for which 3D printing was first used). Again, the surface quality leaves much to be desired. And without post-processing, the item will not have a salable appearance.
A little more and everyone will have a 3D printer. To print something, one needs a model. And here the printer user is faced with the choice to print ready-made models or simulate himself. The average user does not have 3D modeling skills. Print other people’s models? Tired, no model needed. And he would order this 3D model somewhere, but then print can be ordered.