A short guide to 3D printing at school

By Marc-André Girard (@magirard)
A joint dossier of L'École branchée and Carrefour education

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The educational potential of 3D printers is immense. Although the technology has existed since the early 1970s, the market has been greatly democratized in recent years thanks, in particular, to the expiration of several patents on technologies used at the time. Today, these tools are relatively affordable and, if the trend continues, they will become even more accessible in the coming years.

Observers believe that 3D printing will invade the technosphere to revolutionize it and forever change the relationship that humans have with the object. Will 3D printing be the new internet? Will it invade American and Canadian households? Will it revolutionize aid to developing countries? Will it become an essential tool in schools?

This dossier aims to provide a technical portrait of 3D printing and current possibilities in schools. For its realization, the author tested five different models and familiarized himself with the technique, which allows him to reveal some important tips.

File Summary:

1. Introduction: A short guide to 3D printing at school
2. The educational potential of 3D printing
3. 3D printing at school: where to start?
4. " 3d printing 101 ”: function and materials
5. Five 3D printers tested for your educational activities
6. Frequently asked questions about 3D printers

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The educational potential of 3D printing

Already, the medical applications of 3D printing are endless. From printing molds to make in-ear headphones to making prostheses to replace human limbs, it quickly found itself at the heart of many hopes for improving the quality of human life. Companies in the health sector are also striving to try to print human tissue. The L'Oréal company recently announced that it would test its products on 3D printed human skin. A 3D human tissue printing firm, Organovo, has already started the marketing of liver tissues for them to be subjected to toxicological studies. Soon, he will begin marketing nephrological tissue, always intended for medical studies.

Other areas of health are no exception. As much in orthopedics as in dentistry or even surgery, hopes are high: instruments, implants, modeling, prototypes, etc.

Education will not escape it!

While many believe that 3D printing plays an important role in what they qualify as medical revolutionThe question we are asking ourselves is: what are the educational potentialities of 3D printers?

Originally, the integration of 3D printers was part of the STEM educational model (Science, Technology, Engineering and Mathematics). The applications were mainly related to science and mathematics: use of geometrical formulas to better visualize complex shapes, manufacturing of robotics parts or printing of models related to the understanding of the human body.

The STEAM model (Science, Technology, Engineering, Arts and Mathematics) has rapidly enhanced the STEM model. Now, artistic applications have quickly emerged: they allow the creation of models of different works of art of all kinds in addition, of course, to be a new bulwark of creativity for students. We will come back to this.

Finally, the human sciences are not left out. In geography, it has become easy to print reliefs in order to model, for example, hydrographic basins or to conceptualize the development of a district of a city. In history, it is very simple to reproduce various tools used in ancestral techniques in addition to building monuments according to various architectural characteristics ranging from mud houses of the Vikings to the great European cathedrals.

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3D printing at school: where to start?

Different avenues to approach 3D printing for educational purposes ...

More and more schools are encouraging the emergence of entrepreneurship among students. Students can make their own items that they plan to sell. Now the only limit is their imagination: they can make replacement buttons for clothing, soap dishes, tools, eyeglass frames, jewelry, protective cases, etc. Educational companies such as Young Quebec companies give pupils or students the chance to market their products by creating a small student business. Definitely, 3D printers can help facilitate the emergence of a culture of entrepreneurship in schools.

In the same vein, instead of replacing an entire object, why not repair it by printing, when possible, the broken part? In short, creativity is at the service of entrepreneurship. We identify our own needs and those of those around us and we strive to meet them ourselves. It is about the redefinition of the link that each human has with the object.

The use of digital 3D design tools increases artistic possibilities. Historically, excluding sculptural works, students have been used to designing in 2D, either on a sheet of paper, a canvas, or on a digital medium. Now we have to think differently, with different tools. For example, software like SolidWorks is essential because it manages the entire process, from creation to printing. It also allows the user to create elementary 3D parts quite easily. It is also software that is used in several engineering faculties, allowing students to easily design a three-dimensional work and see it take shape.

In addition, combined with other advanced tools, in a digital manufacturing workshop or in a Fab Lab, the creative possibilities are multiplied tenfold. This is the very principle of makerspaces, these digital manufacturing workshops set to take schools by storm in the coming years.

Some printer manufacturers offer educational activities on their website, in addition to access to their community of users, very often from the school network. Of course, most of the educational material created is available in English.

The first Fab Lab in Canada, that of Community (Echofab), offers a workshop of discovery of 3D printing to Montreal.

Also, it is possible to contact other companies that sell or use this technology. For example, Voxel Factory also gives training, whether or not you buy a 3D printer. They offer a printing service for ad hoc manufacturing needs if one does not wish to acquire such a device.

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"3D Printing 101: How it works and materials

Before we get to the question of choosing a 3D printer, there is one important criterion to consider: the filament. It's a bit like wondering about the type of ink cartridges for a conventional printer. And before considering the filament, you need to understand the entire operation of the device.

Operation

By definition, the 3D printer works in a additivethat is, it melts very thin layers of thermoplastic on top of each other that fuse together to form the object designed using three-dimensional design software. This thermoplastic comes, most of the time, in spools that look suspiciously like a string trimmer's replacement wire and is usually hung behind the device, allowing the end of the filament to be taken and connected to the mechanism. extrusion through a tube. The thread is melted as the printer makes an object and the spool unwinds. Subsequently, it will obviously have to be replaced.

These spools are generally sold at a weight of 750 grams of material and said thermoplastic wire wound therein generally has a diameter of 1.75 mm. Contrary to what one might think, the yarn is rarely sold by length!

The two main materials used by 3D printers in schools are ABS and PLA (explained a little later). Here, it seems important to mention that there is no ideal polymer. As with everything, there are advantages and disadvantages to each. In addition, besides ABS and PLA, there are several other materials: nylon, ninjaflex and other types of polymers.

ABS

Acrylonitrile butadiene styrene, better known by the acronym ABS, is a plastic that is very common in our lives. We only have to think of the famous Lego blocks or various plastic parts on small household appliances for everyday use. This type of polymer is known for its strength and it is for this reason that it often serves as a structure for a part or an object. Its melting temperature being relatively high for a polymer, ABS is little affected by high temperatures.

Concretely, an object printed with an ABS filament does not risk deforming if it is near a heater, a household appliance, a light or any other source of domestic heat.

Thanks to its strength, it is possible to manufacture plastic screws or interlocking parts. It is even possible to lightly sand the part.

However, ABS has two major drawbacks. At first, as long as it has not frozen, it remains fragile. This is the reason why the printing is deposited on a heating plate or, in certain cases, carried out in a heated enclosure to avoid the risks of deformation during a rapid change of temperature. Also, ABS can give off an odor of molten plastic. Manufacturers disagree on whether ventilation is necessary and several studies show that toxins released into the air are nearly five times lower than public health standards in the United States. That said, research is carried out at melting temperatures much higher than those used by non-commercial 3D printers.

The meal

Polylactic acid, or PLA, is another polymer used in 3D printers. Its particularity is that it is biodegradable since it is usually made from cornstarch or sugar cane residues. This makes it a particularly popular material since its ecological footprint is smaller than that of ABS. Moreover, PLA is frequently used in food packaging and in several medical instruments. Its melting temperature is lower than ABS. This means that an object printed with a PLA filament risks deforming if it is near a heater, a household appliance or if it is forgotten in the car during a heat wave in summer ...

Many believe that PLA is a less solid polymer than ABS. However, when used for educational purposes, few projects will be able to see the limits of the polymer. Obviously, since PLA is made from organic materials, the smell that emanates from the molten plastic is not very disturbing, even pleasant. While it doesn't go unnoticed, a subtle sweet smell is perceptible, which some say resembles the smell of maple syrup.

The printing of the PLA part is done on an unheated plate. It is generally recommended to place an adhesive tape on it to increase the adhesion of the part. Some choose to spray hair spray to maximize this grip. Others make a special glue for this purpose. To have experienced it, it is indeed desirable to use the tape and the fixative to facilitate the setting of the first filaments printed on the plate. Also, a European company has developed a fixative dedicated only to 3D printing, the 3DLAC.

You can do your own testing, but here's a combination that works well: the two-inch-wide 3M 2090 Blue Tape (available in the paint section of your favorite hardware store) and the 3DLAC hairspray in question. Adhering the PLA well from the start maximizes the chances of a successful print and prevents the part from pitching and possibly damaging the nozzle.

The right coil

The prices for a spool of PLA wire typically range from 40 $ to 80 $ for 750 grams at a diameter of 1.75mm. Ditto for the spools of ABS filament, which can however be a little more expensive. Often, manufacturers offer a slight discount on the purchase of several spools (between half a dozen and ten). Also, companies other than the manufacturers offer spools of filament at prices lower than those normally recommended. Usually one can consider paying ten dollars less.

For example, the Dutch company ColorFabb offers excellent quality filament, in a multitude of colors, at prices around 40 $. They even offer filaments containing bronze dust recreating works of art that can look like real statuettes, once polished! One last detail, and not the least, the ColorFabb filament spool is transparent. This makes it easy to estimate the amount of remaining filament.

Here are two things to consider to save money when purchasing the filament. First of all, the best way to save money is to buy several spools in the same order. There is then the possibility of saving between three and five dollars per item when buying more than ten. Ask your dealer. Second, there is inexpensive filament on resale sites like eBay. Before making such a choice, which risks damaging or clogging the printing nozzle, remember that it is relatively complicated to make repairs yourself on such a device. And spare parts are expensive. When a nozzle blocks, the projects it is supposed to print also block and students are left waiting. It is not to be overlooked. Often, the savings do not justify the educational risks or repairs that await you.

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Five 3D printers tested for your educational activities

First of all, it is important to understand that the market for 3D printers has only just democratized. The devices, although they have significant educational potential, remain a technology that will evolve rapidly. For example, very few printers allow two-color printing. It is expected that this will change shortly. Also, during intensive use in schools, it is necessary to foresee that durability problems are likely to arise. Indeed, the printers that follow are devices that are not manufactured for such intensive use. What makes these technologies interesting for schools is that they represent a compromise between quality and price.

Also, these devices require a good deal of patience. Although 3D printers are paradoxically simple and complex at the same time, the key remains the adjustment of the printing plate. Precision is the secret: if the platen is too far from the extrusion head, the adhesion will be poor. Conversely, if it's too close, the nozzle won't flow and it may clog. The worst part is that in all these adjustments, the difference is a mere millimeter!

1. DittoPro, by Tinkerine

When it comes to this printer, the first quality of the device is definitely that it is made in Canada. Indeed, Tinkerine is a company based in Vancouver, which can lead to believe that the parts will reach us quickly, in addition to being able to transact with them in Canadian dollars.

At a glance when it is in operation, one point is obvious: the emphasis is placed on highlighting the printed object. Indeed, the front of the printer is completely open and well lit thanks to LED lighting. Students can see the different stages of printing and have access to the printing plate quickly and directly. However, they should avoid touching the mechanism, as they might get burned more easily than with other models. Nevertheless, the DittoPro is a real eye-catcher for students.

PLA printing is done on an unheated glass plate. In our case, the device was used in a small office space and there was hardly any smell. The same applies to the noise of the device: apart from the fans, the printing module is discreet. There is no risk of disturbing the classroom dynamics.

Note that the DittoPro is not connected to the computer and only an SD card slot is available in front of the device. This is not ideal in education since it is necessary to ensure that the students all have an SD card. In this era of cloud computing, Tinkerine could have planned to connect their printer to a wireless network. The company says, however, that this choice was made to prevent printing from stopping when the computer goes to sleep. In addition, although navigation in the control screen is easy to use, the wheel button for navigating the menus needs to be reviewed, as there is a lag between its activation and what happens on the screen. . Finally, when an SD card is used, the display shows the time remaining until printing is complete. This is very convenient and helps to facilitate the planning of the educational use of the printer.

In short, the printer in question is easy to use and its mechanism is not of a very complex construction. However, knowing that 3D printers are relatively fragile, it is highly desirable to do business with a local distributor. Voxel Factory is the official distributor for Tinkerine in Quebec and Eastern Canada. Based in Montreal, the company performs maintenance and repair of 3D printers at a rate of 50 $ / hour (or 35 $ / hour if the customer purchased the device from them). The premises are located near the Jacques-Cartier Bridge, in the Hochelaga district.

Overall assessment:

Easy to use, we never needed to calibrate the tray. Relatively sturdy, the lighting and access to the print bed highlight the work of the printer. Requires more products to ensure adhesion (tape and fixative). Excellent value.

Specifications:

• Printer dimensions: 37 x 39 x 43.6 cm
• Printer weight: 10 kg
• Printing volume: 22 x 16.5 x 22 cm (7986 cm³)
• Resolution: between 50 and 200 μm
• Connectivity: SD card, USB (with third party drivers installed)
• Compatibility: Mac or PC
• Material: PLA (1.75 mm diameter)
• Price of the filament: between 40 $ and 80 $ for a 750 g spool.
• Suggested retail price: 2000 $
• Educational discount: 100 $/printer discount offered at Voxel or 200 $/printer discount when purchasing three or more printers.
• Basic warranty: 1 year

Reseller's website: https://www.voxelfactory.com
Manufacturer's website: http://tinkerine.com

2. Mojo, from Stratasys

This 3D printer is certainly the most advanced model of those selected for comparison for school environments. The great peculiarity of the Mojo, made in the USA by Stratasys, is that it prints using two rolls of filament confined in separate cartridges. The first is made of ABS + polymer and the second is a support filament which is water soluble. This last filament allows the impression of a structure to support the impression of different shapes having strong inclinations. It therefore allows the printing of a larger range of objects, even if its printing volume is smaller than that of its competitors.

Due to the use of ABS as a filament, the printing chamber is heated, which eliminates the risk of deformation of the printed part. Everything is secure and inaccessible to students, which removes the danger of burns during the operation. The pupils can however observe the evolution of the creation of the piece through a small window giving a frontal visual access to the illuminated enclosure. Also, Stratasys offers a cleaning station Wavewash in which the part can be immersed in circulating heated water, which facilitates the dissolution of the support filament. Also, when replacing the cartridge, a new extrusion head is provided to replace it to always ensure quality printing and, of course, reduce the risk of jamming. Each time you change the cartridge, it's a bit like having a new printer.

The Mojo is only compatible with a PC computer, to which it is connected via a simple USB cable. The cost of replacing the cartridges is particularly high since a new extrusion head is supplied; however, this ensures minimal maintenance by limiting the risk of clogging the part.

Stratasys is a Minnesota company that specializes in industrial or commercial 3D printers, which are often used by jewelers, engineers or artists. It is distributed in Quebec by SolidXperts, based in Montreal in the west of the island, a company that also provides maintenance service for these printers. For a maintenance plan and a one-year warranty extension, 600 $US is required annually.

In short, the Stratasys Mojo is the gateway to more complex and better finished educational projects, probably of an artistic or entrepreneurial nature. It is a step in the right direction for the production of objects which could be marketed by students leading a personal project or which are part of various entrepreneurial activities.

Overall assessment:

Definitely, the Mojo is a top quality printer. Being able to print objects with steep slopes thanks to the dissolvable backing filament is a plus. However, the price remains high for the needs of the students and the means of the schools. Model more oriented towards corporate clients.

Specifications:

• Printer dimensions: 63 x 45 x 53 cm
• Printer weight: 27 kg
• Print volume: 12.7 x 12.7 x 12.7 cm (2048 cm³)
• Resolution: 170 μm
• Connectivity : USB
• Compatibility: PC
• Material: ABS+ (3 mm diameter)
• Filament price: 399 $US for a 1350 g spool.
• Suggested retail price: 5995 $US including cleaning station Wavewash
• Basic warranty: 1 year

Reseller's website: http://www.solidxperts.com/fra/
Manufacturer's website: http://www.stratasys.com/fr

3. Replicator (5^e generation), Makerbot

Makerbot is certainly one of the most famous manufacturers in the field of 3D printing. Moreover, the company was bought by Stratasys in 2013 to be able to gain a foothold in the market for 3D printers accessible to all consumers. This ensures some access to parts and the availability of technical assistance.

Unfortunately, although this company is recognized as one of the pioneers of 3D printing, Makerbot has experienced major difficulties in recent years with the plastic extruder, which gets clogged frequently. Fortunately, the new extruder (Smart extruder +) remedies the situation and adds a spectacular dimension to the printer. In fact, not only does it stop the printing in progress if it runs out of filament, but it alerts the user on his or her smartphone of the situation. The printer then picks up where it left off. Another interesting feature is that the printer is equipped with a camera in the printing chamber. This means that you can connect to the printer to visually see the progress of the printing process, features that will certainly be appreciated by the students!

The printer has a rugged look and, as Makerbot likes to point out, this is a fifth generation. It is clear that this is an advanced device. Among other things, this is expressed through a large control screen activated by a precise and robust thumbwheel. The colored LED lighting is effective and complements well the black silhouette of the printer. Basic printing information is available on the printer's casing: job completion percentage, print time and time remaining, image of the finished product, etc. This information is also available on the printer's display. This information is also available on theapplication Makerbot mobile.

The filament spool is inserted at the back of the device, in a compartment provided for this purpose; it is therefore not apparent. This adds to the aesthetics of the product. A small window is provided to see the amount of filament remaining in the spool.

Like the Stratasys Mojo, the Replicator is also distributed in Quebec by SolidXperts.

Overall assessment:

The connectivity of this device is fantastic. It easily connects to a Wi-Fi network and jobs can be sent wirelessly to the printer. The camera is an asset to allow students to see where their project is at. However, the printer is particularly noisy, which may interfere with the smooth running of a lesson.

Specifications:

• Printer dimensions: 52.8 x 44.1 x 41 cm
• Printer weight: 16 kg
• Printing volume: 25.2 x 19.9 x 15 cm (7522 cm³)
• Resolution: 100 μm
• Connectivity: USB, network, Wi-Fi
• Compatibility: Mac, PC, Linux, iOS, Android
• Material: PLA (1.75 mm diameter)
• Filament price: 48 $US for a 900 g spool or 430 $US for 10 spools
• Suggested retail price: 2899 $US or 3887.99 $US for a printer combo, 10 spools of filament and an additional year of warranty and service.
• Educational discount: There are no educational prices, but there are occasional promotions.
• Basic warranty: 6 months. Extended warranty available for 1 year (350 $US), 2 years (720 $US) and 3 years (1105 $US). The warranty includes telephone technical support via Makerbot and the cost of parts. This excludes the service of a professional.

Reseller's website: http://www.solidxperts.com/fra/
Manufacturer's website: http://www.makerbot.com

4. The Ultimaker 2+

This 3D printer model is somewhat reminiscent of the early models manufactured with a slightly more retro look than its competitors: a brushed gray metal body with frosted plastic panels riveted to both sides as well as the back of the device. On the other hand, the top and front of the device are completely open, allowing for a short, but easy access to the print area. It offers one of the best print volumes of the printers featured in this review. The enclosure is also well lit with LEDs.

Interesting point: the Ultimaker 2+ loads the filament by itself. Simply place the tip of the filament in the hole behind the machine and select the material loading menu on the screen and it's done. According to the manufacturer, this feature keeps the filament as far away from dust as possible.

Also, the Ultimaker2+ is very versatile since it can vary the materials used: PLA or ABS. Its printing plate is therefore heated. However, it is important to make sure to calibrate the plate before printing, because the plate seems to be easily misadjusted. Moreover, if the platen is poorly calibrated, the first print layer simply does not adhere. Also, the printer comes with an assortment of four nozzles (0.25 mm, 0.4 mm, 0.6 mm and 0.8 mm) that are easily changed by simply unscrewing them manually before printing. This increases the level of precision of the print.

The printer is working fine, but it is a bit noisier. A few beeps are heard when the extrusion suddenly changes direction. The electrical connection behind the device could be reviewed; the connector looks like an old wire S-Video, which is not easy to connect.

The connectivity of the device is made possible thanks to an SD slot, but also thanks to a USB cable.

Ultimaker is distributed across the country by Shop3D, a company based in Ontario. The service in English is impeccable and prompt, even if it remains difficult to send technicians on site in Quebec.

Overall assessment:

During the test, we had to adjust the chainring several times and try our luck several times, but once we found the right fit, everything was impeccable. Also, this model is more versatile so as to satisfy the needs of several users at the same time. Peeling off the part from the print bed is also a snap once the print is complete. Finally, the fact of using a filament of larger diameter seems to make it easier to handle the spool, and therefore the supply.

Specifications:

• Printer dimensions: 49.2 x 34.2 x 55.8 cm
• Printer weight: 11 kg
• Printing volume: 22.3 x 22.3 x 20.5 cm (10,194 cm³)
• Resolution: between 20 and 600 μm
• Connectivity: USB, Wi-Fi, SD card
• Compatibility: Mac, PC, Linux
• Material: ABS and PLA (2.85 mm diameter)
• Price of the filament: 50 $ for a 750 g spool.
• Suggested retail price: 3625 $ (including delivery and preventive maintenance)
• Basic warranty: 1 year parts and labor (excluding the extrusion head)
• Extended warranty: two additional years for approximately 750 $ annually

Reseller's website: http://shop3d.ca
Manufacturer's website: https://ultimaker.com

5. The Cube Pro Trio, by 3D Systems

In many ways, the Cube Pro Trio is a printer that is different from the other printers in this testbed. First, it is much larger and heavier. This means that it can print larger parts, but at the same time, it takes up more space in the classroom and is less portable. Secondly, it allows for three-color printing (or two-color printing for the Duo model, or one-color printing for the basic model) thanks to three extruders that are part of the same print head. It is a more versatile printer since it can be used with three types of filament (ABS, PLA and nylon) in addition to a dissolvable filament that serves as a temporary support for printing strongly inclined shapes. Finally, all the magic happens inside the machine: the filament is located there and unfolds in the tubes. The enclosure is also heated during printing and this heat is automatically regulated by a small chip in the filament cartridge. In short, this chip informs the machine and the software of the type of filament it contains and the color of the filament. Since PLA requires less heating than ABS or nylon, there is a way to open the door in front of the printer and remove the top and back panels to get a good view of the operation.

The printer offers an interesting degree of automation, requiring less manipulation on the part of the users. The supplied software is comprehensive, although less intuitive and user-friendly than others. A special glue is supplied with the machine and it must be applied to the print bed. Once the operation is complete, the plate only needs to be rinsed and it is ready for use again.

This printer offers three levels of resolution and three padding options that can be adjusted using software and no matter what choices you make, printing takes place relatively noisily. This is because the print bed moves in concert with the print head during operation. As the printer is downright a cube (hence the name of the model) and part of the closed structure seems sturdy, we would expect some level of soundproofing. On the other hand, the quality of the printing is excellent. Point to emphasize: the printing in ABS took place without any odor.

Cube line printers are manufactured by 3D Systems and distributed in Canada by Konica Minolta. The basic warranty is one year, but it covers parts only. They must therefore be changed by the user using a telephone service based in the United States.

The cartridges are sealed to protect the filament from moisture. While installing these cartridges is relatively straightforward, removing them involves a certain waste of material since what is removed from the printer cannot be rewound into the cartridge. This is particularly sad, especially since the cartridges are more expensive than those of the competition and it is impossible to replace them with filament from another manufacturer. However, for those with ecological considerations, 3D Systems offers a recycling service for cartridges, unused filament as well as printed parts. All you have to do is mail it to one of their recycling plants in South Carolina or Germany.

Overall assessment:

This printer offers a huge design space and gives a great impression of technological innovation in the management of cartridges. However, their loading is not easy since it is done inside the machine, in a cramped space; if you have big hands it won't be a pleasant experience!

Specifications:

• Printer dimensions: 57.8 x 59.1 x 57.8 cm
• Printer weight: 11 kg
• Printing volume: 20.04 x 23 x 27.04 cm (12,463 cm³)
• Resolution: between 70 and 300 μm
• Connectivity: USB, WiFi
• Compatibility: Mac, PC
• Material: ABS, PLA and nylon (1.75 mm diameter)
• Filament price: 132 $ for a 670 g spool (sealed cartridge)
• Suggested retail price: 5279 $ (excluding 120 $ shipping cost)
• Basic warranty: 3 months parts and labor (excluding the extrusion head)
• Extended warranty: 9 months (398 $), 2 years (664 $) and 3 years (1063 $)

Reseller website: http://konicaminolta.ca/business/products/3d-printers/index.html
Manufacturer's website: http://www.3dsystems.com/

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Frequently asked questions about 3D printers

1. How much does it cost to print a part?

Obviously, this is the first question that comes to mind, as it can be expensive to allow all students access to the printer without control. A simple formula can be applied:

(Spool price / spool weight) x part weight produced = part price

As an example, here is a small Aztec figurine that measures 8cm in height, 4.5cm in width and 3cm in depth. It is filled to 15 % inside since it is unnecessary to fill the entire object and this saves a lot of filament, and therefore money, without however affecting the quality of the latter. The average cost of a quality spool is 50 $ for 750 grams of filament. When printing this 24.5 gram part, the total filament cost would be 1.63 $. This excludes the cost of depreciation and maintenance of the printer itself. Note that print management software usually displays the weight and quantity of filament (in meters) used. It is therefore easy to do the math without necessarily having to make a first impression.

2. How long does it take to print a part?

3D printing takes time, which is a somewhat dichotomous reality with the advent of new technologies in society. Indeed, we are in the era of instantaneity; 3D printing will bring students back to praise slowness and precision with plenty of time for wonder and the development of patience. That said, teachers should plan their activities well, because if they think they can print a few coins during their term, they are wrong!

Specifically, the printing time depends on several factors:

• The size of the room;
• Its filling;
• Its design complexity (slopes, details, etc.);
• The quality (or resolution) of the print;
• Printer capabilities.

It is therefore difficult to answer precisely. However, this information is usually disclosed in print management software. Also, as an indication, the Aztec figurine mentioned above will have required 3:06 of printing.

3. Is it possible to print several parts at the same time?

Yes, it's just a matter of organizing the print tray in the software according to the projects and you're done. However, keep two things in mind: first, beyond the feeling of maximizing the use of the print tray, the more you increase the job, the longer it takes to print. Second, make sure your software is able to print all the parts at once, not one at a time. If one part is printed first, it becomes difficult for the extruder to walk around the printing plate properly and this is very likely to cause breakage.

4. Can we print at night?

This is indeed a widespread practice, but it is not recommended for two main reasons: first, if there is a problem with the process, no one is on hand to intervene (filament shortage, jamming, etc.). In addition, manufacturers do not recommend unattended use of the machine, especially since it involves heating and melting polymer.

5. What happens if the filament spool empties during printing?

It depends on the printer. Rare printers allow printing to stop and then resume when the spool has been changed. Filament detection systems weren't implemented in all machines, at least not for non-commercial printers (excluding Makerbot's Replicator). In this case, the extruder continues to print, but without polymer. There is therefore no filament exhaustion detection system.

However, software usually estimates the amount and weight of filament needed to make the part. As a result, there is a way to weigh the spool of filament to get an overview of how much is left. For greater accuracy, weigh an empty spool and subtract the weight from that in the machine.

6. What is the print resolution?

From the outset, it is important to know that 1000 microns (μm) is equivalent to one millimeter. So, the smaller the resolution number, the higher the resolution. On flat parts, this does not matter, as the difference between a resolution of 20 μm or 200 μm is imperceptible to the naked eye. However, for gradients, curves or slopes, it will make a significant difference.

The majority of manufacturers or experts in the field recommend a resolution of 60 μm for manufacturing a high resolution part. For a part that is not intended for a use where aesthetics is essential, for example for preliminary tests, 200 μm is more than enough. Keep in mind that the higher the resolution, the higher the print time.

7. Can I print in two or three colors at the same time?

Some machines offer this possibility with a double extruder (see, among others, the CubePro Duo or Trio from 3D Systems). Other printers, meanwhile, offer the "pause" function where it is possible to manually interrupt printing to change the filament. Otherwise, some parts fit together; just print the different pieces in different colors.

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Sincere thanks to :

• Mr. Jean-François Niaison, president of SolidXperts.
• Mr. François Lahey, co-owner of Voxel Factory.
• Messrs Kenneth and Jacky Wan, co-owners of 3DShop.
• Messrs Jamal Hashim and Jean-Pierre Houle from Konica Minolta, partners of 3D Systems