Formlabs Form 1+ in the Detailed Practice Test

SLA is the 3D printing technology, which is said to surpass plastic. In the test, we put the Formlabs Form 1+ on the test.

In 3D printing for hobbyists, stereolithography is established as a further printing technique in addition to FDM deposition (Fused Deposition Modeling). One of the best-known representatives is the form 1+ of Formlabs. It is intended as a desktop device for engineers, designers and model builders and should be suitable for prototypes and castings thanks to high print quality and precision. We took the printer to the test lab and looked at it in practice.

Hardware installation – simple and clear

The printing process of stereolithography does not rely on plastic, which is rolled up or used as rods, but on liquid synthetic resin as a printing material. This also makes the installation of the Formlab Form 1+ different from an FDM printer. When the Form1 + comes out of the box, the 3D printer is pre-calibrated ex factory. In order to get it ready for use, we use the resin basin, into which we fill the plastic resin up to the specified mark (about 200 milliliters). The printing platform sits at the top of the device and can be simply pushed into the holder using a lever and fixed. The platform itself is pointing down, because Form 1+ creates the 3D objects copywriter. It can be used to build objects up to a size of 125 x 125 x 165 mm (width x depth x height). This completes the hardware setup. In the test it proves to be very easy to carry out.

On the 3 printer itself there is a display and a control knob. When we switch the Form1 + on for the first time, it automatically adjusts the basin and platform. The 3D printer looks quite futuristic with its orange-colored hood, which extends across the entire pool and printing platform. But the cover has quite practical reasons: it protects the printer from unwanted UV light and ensures that its rays do not escape uncontrolled outwards. This is because the 3D printer hardens by laser, which hits the liquid from below, the resin at precisely the places at which the 3D object arises. At the same time, the printing platform sinks into the basin from above. In order to cover the entire platform with the laser, it is deflected by mirrors inside. The 3D object grows layer by layer as it hangs over the platform.

Important role – the printing software PreForm

The method of stereolithography requires a precisely prepared 3D printing template.This assisted accepts the Form1 + program preform, which can be downloaded free of charge from the mold Labs site and for Windows is available from XP and Mac OS X.Preform uses English as a menu language and can handle STL and OBJ files. If we open the program, the first step is to define the layer thickness and the print material. Here, you should pay close attention to what is on the bottle label, because the resin varieties differ fundamentally. In the test, we use transparent plastic resin of the type Clear with the designation “02”.

In addition to adapting the size and position of the object on the platform, the definition of support structures is particularly important. This is because without them the printing process can go wrong. We experienced this in our first experiment: When we print out the standard test object – our Saheltopf – without auxiliary structures, it falls into the basin immediately before it is finished. We must stop the process.

The support can be automatically generated or defined manually in the program. For the latter, we click on “Advanced” in the support menu and define the details such as the strength of the auxiliary platform or the distance between the platform and the object. Practically here is the link to the help pages of the manufacturer, because absolutely self-explanatory are the names at the first moment not.

Another word for support: auxiliary platforms are defined in preform with intention with notches. This is what we want when we want to release the finished item from the platform. This is because the spatula and air penetrate between the building surface and the object at the given points. Thus it dissolves without great effort. In addition, the notches prevent the metal surface of the platform from scratching.

Formlabs Form 1+ – last steps before printing

Once all settings have been made, click on the orange button in Preform. Now showing software to the compressed prediction: the fluid requirement, the number of printed layers, the printing time and the defined pressure locations. All true, we click on “Send to Printer” and the program calculates the 3D print file – the G-code it immediately at the via USB sends connected form Labs form 1+.

The finer the resolution, the longer the program needs to calculate the G code. The temporal differences are serious: with the highest resolution (0.2 millimeter layer thickness), it takes just 56 seconds for the G code to land in the printer’s memory. If we select the finest resolution (0.025 millimeters), the computation time increases to 9 minutes. If the form 1+ has loaded the print file, the USB connection to the printer can be solved, because it works exclusively from the internal memory. However, the actual print does not start until we press the button on the display.

Print speed and print quality of Form 1+

When it starts printing, the platform sinks into the resin basin. We have little to do with the process itself. From the outside we see only the light beam, as it hits the platform through the basin. Remarkable: For a 3D printer the Formlabs Form 1+ works very quietly. The reason: the mechanical movements are limited to the lifting and lowering of the construction platform and a minimal pivoting of the resin basin. Exposure through the laser is completely silent. Over time, the print object “grows” out of the liquid.

During printing, the display shows both the remaining time, the sum, and the finished layers. The time calculated by the print program exactly matches our measured values. This is rather unusual for a 3D printer. Our previous test candidates of the FDM department gave here mostly approximate estimates rather than a reliable value.

The Formlabs Form 1+ has a total of four print resolutions. They range from 0.2 to 0.025 millimeters of layer thickness. Clearly, the pressure in the coarsest resolution is the fastest. For our small potty, the 3D printer requires just 50 minutes. Conversely, at the finest resolution, 5:56 hours pass before the potty is finished. The difference can also be determined by the layers: From 196 layers, the effort increases to 1568 layers in the finest mode.

Work after printing

When the object is finished, the platform moves upwards and the object hangs on it. Now the moment has come for the disposable gloves that Formlabs has added in the finishing unit. Because we take off the construction platform together with the object and place the object upwards on the work board intended for the reworking. There are two plastic containers, a spatula and a fine pair of pliers. The equipment is supplied with the Form 1+. Also advisable are lint-free paper towels, such as the kitchen roll.

With the spatula, we remove the print object from the platform. For this purpose, we attach to the given notches on the auxiliary platform and allow air between the platform and the object. Now it is easy to take off and put into the plastic container, which we previously filled with alcohol. This is not included in the scope of supply. You need to get it at the pharmacy.

In the liquid we swivel the object for about 2 minutes and let it bathe for another 10 minutes. Since the alcohol takes the stickiness of the synthetic resin, the object should be completely covered by the liquid. Formlabs advices another 10 minutes in a second container with alcohol. Then we take out the object and place it on the microfiber cloth provided for drying.

We first clean the construction platform with the spatula and then use the kitchen towels to completely remove the resin residues and to clean the spatula. This should happen quickly after the pressure, since otherwise the resin residues are hardened by daylight and are difficult to get away. The object is best dried overnight, before we release it from the support structures. The supplied pliers provides good service. As a rule, the supports can be removed well. If there are leftovers, we can file them away to increase the stability of the object.

Print quality – fine, but not always error-free

The Formlabs Form 1+ delivers extremely fine objects. Not always the highest resolution but a guarantee for a top result. Thus our pot shows the best result at 0.0.5 millimeters of layer thickness, but not at 0.025 millimeters. In every resolution, a minimal layer remains visible, even though the surface is completely smooth. Small errors occur in each resolution stage. This can be due to the quality of the original, but also to the print material. So rare but small errors do not seem to occur. Because form Labs itself offers on the website information on how they can be repaired after printing. One possibility: to dip a toothpick into the resin and the incorrect place – about a hole – in order to fill. Cured then under a lamp or simply in the sun.

An indication of the form Labs, which has reached us after the test and we are happy to pass on: Especially for objects with a flat base to SLA behaves fundamentally differently than FDM. While plastic 3D printers can easily layer a vessel like our potty from the ground, SLA printers behave completely differently here. The solution: Either one prints the object with the open side to the platform. Or printout him wrong – say, 10 to 45 degrees offset from the platform and defines support in this area to ensure the maintenance of the building platform. Instructions for placing a master’s form Labs on the support pages.

Overall, the printer results from the SLA printer are definitely better than from a device that works with ABS or PLA. This is shown by our small statue: Even in the coarsest resolution, the network structure is absolutely clean. Disturbing elements such as threads in the interstices, which often occur in plastic 3D printers, master the stereolithography without problems. Also corners and vaults are worked exactly.

Consumption costs – SLA is costly

In the case of FDM printers, the consequential costs primarily focus on the plastic. Stereolithography printers, on the other hand, are more expensive to use. Not only the resin belongs to the consumables, but also the resin basin. According to Formlabs it is to be exchanged after 2 liters, since the ground is clouded and the laser can not work with it exactly. In addition, an extra tank is required for each color or type of resin – Cost: 55 Euro.

There are currently seven different varieties at Formlabs. They range from transparent (Clear) to flexible (Flexible) or extra strong (Tough). Also a variety that is designed for casting mode position (Castable). Here, the envelope burns without residue. One liter of resin currently costs 135 euros. Our potty weighs 15 grams. This costs it 2.03 euros. This is a hefty price, which is above all the plastic-processing 3D printers computed so far.

Add to that the alcohol: Since the printed object must be completely covered with liquid, we need almost one liter for our small test objects. Isopropyl alcohol is currently not available under 10 euros per liter. Nitrile disposable gloves are handy with the synthetic resin and the alcohol. They are numerous and will not cost the world with about 7 euros for 100 pieces later.

Conclusion – 3D printers for professionals and enthusiasts

The Formlabs Form 1+ is clearly designed for professional use. The SLA printer is easy to install, designed for continuous use, has a balanced, very clear printer software and can work without problems without any problems. True 3D printing fans will have their pleasure with it, but the handling of the resin and the alcohol is somewhat unusual at first. After a while, however, you get exercise and get along easily.

Overall, stereolithography is clearly superior to the FDM method in terms of print quality. This is reflected in the beautiful details of our print objects. However, this quality also costs a jaw. Because of the equipment price of 3400 euros not only synthetic resin, but also alcohol, substitutes and gloves are added to consumable materials. And, of course, the joy of experimenting is the same as with all 3D printers. Until the right material and the optimal settings are found in the software, some trial runs are required. To go the process is worthwhile however with the Formlabs Form 1+ in any case.


Formlabs Form 1+

design type

finished product

Minimum thickness (in mm)



synthetic resin

printing technology


Dimensions ready for operation (W x D x H in mm)

275 x 300 x 450



Print quality

Standard quality

very good

highest quality

very good

Pressure table adjustment

very accurate

Print quality with support

very good


Test object in low quality (in hours)


Test object in the highest quality (in hours)


Heating to operating temperature (in minutes)

not applicable


Max. Object size (W x D x H in mm)

125 x 125 x 165

supported printing materials

Flexible, Tough, Castable, Clear, Color

Building platform heatable


Display / memory card slot / USB host

Yes / no / no


USB 2.0

LED lighting

Yes (button only)

Supported Operating Systems

Windows XP, Vista, 7, 8, Mac OS


Form Labs Blog / our site

Weight printer ready for operation (in kg)






Well, many setting options

file formats


Display: language / menu structure

English / overview

Construction Printer: Installation / Material Assembly

Very simple / very simple

Printing: Stability printer / unattended printing

Very stable / yes


Power consumption (operation / rest / off)

23.1 / 12.6 / 0.9

Printing material (price per kg)

135 euros

Price test object (15 g)

2.03 Euro

Additional consumables:

Isopropyl alcohol, gloves, resin basin

Price (printer)

3399 euros