3D printing has now become very popular, even fashionable, owing to the ready availability of cheap devices printing in the FDM technology (Fused Deposition Modelling – the name used in Stratasys devices) and the printing material. The availability and the media hype leads the customers and the less experienced owners of single-nozzled printers to believe that anything can be printed, from any material, in any quantity. We are approach by people with various questions, worse yet, we have clients who were given crooked printouts or models with support structures incompletely removed. They prompted us to write the following article.
Is it possible to print everything?
Yes and no. There are various printing technologies offering great possibilities, let us focus on the FDM, however. The question should rather be: does it make sense to print everything? Let us not forget about other methods of production. Indeed, printers have not replaced all other machines yet. If the project is a flat plate wit a few holes, maybe it is better to buy a piece of Plexiglas or another material and drill the holes? It will be more durable and probably cheaper. Unless, of course, someone feels it is a matter of prestige that the project has materialized on a 3D printer.
Complex printout shapes
3D printing makes most sense in the case of complex geometry components. We can print casings for various electronic devices, fans, etc. Usually in order to test the design before we order an expensive injection mould. However, a complicated geometry of a model can be quite a challenge for owners of one nozzle printers, making support structures with the same material as the model. The supports have to be mechanically removed, broken off, which can cause damage to the model, and the “printer” himself has more work to do. With some nooks and crannies, the removal of supports with may indeed prove impossible.
Fair exhibitors showcase very nice printouts, vases, etc., or items made for the printer (e.g., a wrench which is flat on one side). However, hardly anyone features printouts of prototypes. After all, it is not about designing only what can be printed. The problem of mechanical removal of the supports is solved with soluble supporting material laid by the second nozzle. Such a solution is used in the 3D printer we use. Both, the material for the model and for the supports is closed in watertight cartridges with a moisture absorbent, and is supplied in a hermetically sealed package. The ABS material absorbs moisture, with a detrimental effect on the material. In the case of printouts which only need a specific shape, it does not really matter, whereas it is crucial in models with such elements as latches.
3D printing still cannot substitute mass production by injection moulding. Several dozen printouts may pay off, however, the cost of printing hundreds of items, even if they are simple elements, will reach the cost of making a mould. All because of the printing time, which is a component of the service’s price. An element made with an injection mould can be done in several seconds, with a printer – a couple of hours.
Scale models – it is not enough to downscale the project
When someone wants to print a model of his design of a building or a machine, it is often, regrettably, not enough to downscale it, e.g., 50 times. After the downscale it turns out that some elements will have walls too thin or even be too small to be printed. For example, a machine has a metal cover sheet with a thickness of 1 mm, and the machine needs to be printed at 1:20, which means the cover should be printed at 0,05 mm, which is impossible. Moreover, a model sometimes contains empty spaces, which will be filled with support structures. Such a design will usually need to be modified for print or even designed from scratch.
How much will it cost?
It is obviously the first question asked, often all the information we get are the model dimensions. In order to receive a quote for a 3D printing service, it is not enough to provide the model’s volume or its dimensions. This could only be enough to specify the cost of plastic that will be processed for the model. The price of the service also includes the material for support structures and the time of printing, and this in turn depends on the complexity of the model’s geometry, its orientation in the printer’s work space, the layer thickness, etc. In short: the cost of printing a 1 cc model A may differ substantially from cost of printing a 1 cc model B, which is the reason why you must not believe the online calculators quoting printouts, which probably provide overpriced costs. One might as well ask how much it costs to travel from Berlin to Warsaw, about 500 kilometers in a straight line. The answer depends on which mode of transport you choose.
The 3D model is essential
In order to even start talking about 3D printing one needs to begin with creating a 3D model. An element’s picture, sketch or even a physical model of a defective part is not enough. With the help of additional software, callipers or a 3D scanner they may serve as a basis for a virtual three-dimensional model, drawn or designed. The creation of the model can be ordered too, but it will increase the cost of the service. Similarly, if someone wants to print a book, it first needs to be written.
3D printing is a service, not plastic
Recently, during a presentation of a company manufacturing 3D printers, I heard that printing of a prototype of a car vacuum cleaner cost 200 zł, the speaker ignored the fact that it is only the cost of the model material. After such presentations, the people who wish to print a small broken part think they will pay a few złoty, since the vacuum cleaner cost only 200. We often have requests about replacing damaged parts, without 3D files. It should become well-known that 3D printing service is not only the plastic that is given to the customer. It is also a few work hours to create a 3D model, sometimes using expensive hardware and software, the knowledge and experience, the electricity and other costs of running a business. This is why the cost of such services often exceeds the purchase price of equipment that the customer wants to repair. Despite such explanations, the clients become outraged: a few hundred złoty for such a small part? Does anyone quarrel with a taxi driver they would not pay 30 zł instead of 5 zł because the taxi has not used more than a litre of gasoline on the way? Reconstructions of used parts only make sense when unique elements are replaced or in order to test a prototype before its mass production.
In this article we aimed to explain what the 3D printing service is and what is its potential and its limitations. 3D printing was invented over 25 years ago for rapid prototyping in the industry. It has now become popular by cheap printers, able to produce models of very good quality, but not necessarily with a high degree of complexity. Those are made well by printers for a price of a car.