Sinterit Lisa Pro test: affordable, accessible and quality SLS 3D printing

Sinterit is a Polish manufacturer dedicated to making SLS 3D printing more affordable and accessible.

Introduction

Sinterit launched its first desktop SLS 3D printer- the Lisa- in 2015, and has been growing ever since. The Lisa is now in its third generation of updates.

Sinterit Lisa Pro test and review

Following the success of the Lisa, Sinterit announced the Lisa Pro in 2017, aimed at professionals wanting a higher volume of printing. At this price and accuracy level, the Lisa line of powder 3D printers is now unparalleled; Sinterit is virtually the only player in this niche market.

We were invited to visit the Sinterit facility for a few days to meet the team and test the Lisa Pro.

Benefits

• Excellent part quality and accuracy
• Intuitive interface and software
• No technical training required
• Affordable access to SLS technology
• Integrated printer farm function in the software
• Rigorous quality control and pre-calibration
• Reusable powder

Disadvantages

• Powder can get everywhere
• Can’t really be used in an open space office (dust, heat, clutter)
• Long printing and post-processing process (more than 20 hours for a small piece)
• Relatively limited choice of materials and colors (Nylon/TPE/TPU in shades of gray)

Test Sinterit Lisa Pro: our opinion

The Sinterit Lisa Pro offers accurate results with nice finishes and is easy to use, even for beginners. It is capable of printing complex and functional parts in one go, without support structures, and the unsintered powder can be reused.

Its main drawback, compared to ordering a part online or using an FDM 3D printer, is the “volatility” of the powder. It’s easy to get a little bit everywhere! While the Lisa Pro can technically be placed anywhere due to its relatively compact size, it is best to allocate a dedicated room for it.

In any case, it’s a great choice if you’re looking to produce parts in small batches or if you need to print prototypes regularly. It is also a solid alternative to using a 3D printing service; depending on your output, you can quickly recoup your initial investment and reduce your production costs.

Sinterit Lisa Pro : features and price

Printing volume

The Sinterit Lisa Pro offers a print volume of 150 x 200 x 260 mm. This may seem small if you’re used to FDM 3D printers, but it’s actually quite large for an SLS 3D printer, especially in this price range. Diagonally, you can print parts measuring up to 316 mm long.

Features

This 3D printer is equipped with interesting features such as a nitrogen chamber and a large touch screen with access to the webcam installed in the printing area. It is also possible to view the printing process through the small “window” on top of the printer.

Dimensions

The Sinterit Lisa Pro takes up a little space, measuring 690 x 500 x 880 mm and weighing about 90 kg. The Sandblaster (480 x 370 x 360 mm, 15 kg) and the sieve (600 x 340 x 300 mm, 22.5 kg) must also be taken into account.

Materials

Sinterit sells three types of powder available in several shades of gray:

• Nylon (PA12 Smooth and PA11 Onyx)
• TPU (FLEXA Black, Grey, Soft and Bright)
• TPE

Prices of the powders per kilogram range from 60 € (PA12) to 250 € (FLEXA Bright). The “FRESH” powder costs 120 €/kg (PA12). This should be added to your non-sintered powder (i.e. the powder left over after printing) at a rate of 30% in order to be able to reuse it.

The choice of materials is rather limited compared to what can be found for filament or resin-based 3D printers, both in terms of the type of plastic and the colors.

Nevertheless, you can also use third-party materials with the Lisa Pro, and its nitrogen chamber allows you to test more sensitive materials, like PA11.

Note: In some cases, to print sensitive materials, it is necessary to introduce an inert gas (such as nitrogen or argon) into the print chamber. The presence of a neutral gas prevents the powder from being contaminated by impurities in the air or simply by the oxygen itself.

Software: Sinterit Studio 2019

There are several versions of the Sinterit software. They essentially determine what materials you can and cannot print. By default, the Lisa Pro comes with the “Open” version, which allows you to print PA12, PA11 (nitrogen required) and FLEXA Grey and Black.

To print with FLEXA Soft, FLEXA Bright or TPE, you need the “Advanced” version (1290 €).

Sinterit Lisa Pro test: getting started

Hardware

The Lisa Pro has a nice design with clean finishes.

On the front of the printer, there is a large color touch screen and a magnetic panel hiding access to the motors, parts that should not be touched when the printer is running.

The right side of the printer includes the power button and a key lock (without the supplied key, the 3D printer cannot be started). Also on this side is the powder overflow tank, where unsintered powder can be collected.

To the left of the printer are the nitrogen hoses, covered by another magnetic panel.

The printer cover is thick and contains the laser system. This makes the cover slightly heavy to lift, but it is not disturbing. On the lid there is also a small (eye-safe) tinted window to look at the prints.

Software

Overall, the software is very complete. Sinterit Studio offers a simplified interface with five tabs:

• Preset: choice of printer, material and layer thickness
• Models: import of file(s), model placement and rotation, etc.
• Slice: conversion of the 3D model into a SCODE file
• Preview: view individual or cumulative layers
• Printers: send the model to the printer, view the process via the webcam and the estimated time remaining
  
  The “Models” tab allows, like many slicer software, to change the position of the model, view it from different angles, and other standard features. You can also stack different models on top of each other – one of the biggest advantages of SLS technology – and the software will show you any overlaps.

The software displays three different areas in the print space. The green area in the center represents the official print volume listed on the Sinterit website. It is possible to place templates in the yellow and red areas, but in this case Sinterit does not guarantee quality results.

The “Printers” tab allows you to set up a theoretically infinite network of Lisa and Lisa Pro 3D printers. If you want to run a “farm” of Lisa 3D printers, it’s entirely possible. At the time of our visit, Sinterit had over forty printers connected to the software.

However, while the software allows you to send files to printers, it does not allow you to start printing. This is a security measure, and you have to manually start printing on the touch screen of the printer in question.

A feature that could be interesting is a cost calculator, in order to know more or less the price of printing a particular piece. It is still possible to do the calculation yourself with the data generated by the software (it displays the amount of powder to be used and recycled).

Experiment: printing with the Lisa Pro

Below we detail the main steps we followed to print our model on the Lisa Pro. Grzegorz Konwlinko, technical specialist at Sinterit, guided and accompanied us.

1. Preparation of the model with Sinterit Studio
The software is very simple and intuitive to use, just follow the clearly defined and indicated steps.

We first selected the printer model (Lisa Pro) in a drop-down menu, then the material (PA12) and the layer thickness (0.1 mm).

In the next step, we imported our STL file. Usually, placing the model in the print volume can be tricky, as there are several rules or rather tips to follow in order to avoid deformations (we will publish a post about this soon). Our model did not need any special placement.

After placing it flat in the print area, we started the preparation (cutting) of the file, then sent the result (SCODE file) to the printer via the “Printers” tab.

2. Launching the printing on the Lisa Pro
Once the model was sent to the printer, we selected it on its touch screen. The screen also offers a simplified interface, leaving little room for errors and oversights.

The printer adjusted its powder bed to the right height. This way, we didn’t have to fill the entire print volume, but just the right amount.

At first, not wearing a mask seemed strange, as one might think that inhaling plastic powder particles could be harmful. However, Grzegorz assured us that this was not the case at all.

Anyway, after pouring the powder into the printer, we packed it down with a dedicated tool. We then poured a little powder on top to fill the remaining void.

Note: The powder is similar to flour, and is very volatile. Therefore, care must be taken when pouring the powder into the printer. It should be poured gradually and gently. It is also recommended to wear gloves when handling the material.

After we tell the printer that we have finished inserting the material, the rollers in the printer automatically level the powder. The surface of the powder must be completely flat before the printer can operate.

Once the powder was leveled, and after closing the lid and pressing “Start,” the printer began to heat up its print area. The rollers also spread a few layers of powder on the print tray so the model doesn’t get stuck to it. The touch screen displays useful information and data, including estimated time remaining and print chamber temperature. It also provides access to live webcam recordings.

Currently, it is only possible to view the webcam stream for ten seconds at a time. The stream must be accessed via the PC software to view the prints without time limit.

3. Post-processing of the printed part
With the heating time (up to 170°C) and the cooling time (up to 50°C), the printing took a little more than 20 hours. That’s pretty long considering the small size of our object.

We waited a little longer, until the temperature of the printer was down to about 35°C.

Note: In most cases, it is best to wait until the print chamber has cooled to room temperature. This avoids warping (deformation of the part).

We opened the printer and followed the instructions on the interface. The tray at the bottom of the print chamber rose automatically, revealing a large block of powder. We picked it up with a special box-like tool (see video below) to place it in a tray.

Once the block was retrieved, we picked the object from the bottom of the powder and brushed it off to remove the unused powder.

Next step, the sandblaster. This tool expels abrasive material through its nozzle, removing the last particles of powder and slightly smoothing the surface of the printed parts.

In our case, this step was not enough to remove the powder that was stuck between the moving parts in the walls of the box. Therefore, we could not close the box. After a few unsuccessful attempts with a scalpel, we finally let the part soak in water for a few minutes, and the matter was settled.

4. Recovery of unused powder
The last step consists in recovering all the unsintered powder in order to recycle it. The printer screen guides the user through each intermediate step.

First, the printer lifts the tray from the bottom of the powder bin. Then, simply push the powder into the slot on the right side of the printer. The powder falls into the hopper, a drawer that can be removed on the outer right side of the printer.

This step is very easy and takes only a few minutes.

Note: Before and after each print, you must also clean the glass laser cover located in the printer’s lid, as well as the two temperature probes located inside the printing volume.

To remove the powder tank, it must be unlocked via the touch screen. Then the tank must be emptied into the sieve. The remaining powder from the print volume block (see the beginning of the previous step) must also be poured into the sieve shaker.

This machine allows to recover the non-agglomerated powder. It lands in a kind of container that looks like a paint can and that can be closed and stored directly.

We ran out of time, but during this step, one is also supposed to add a certain amount of FRESH powder to the powder so that it can be reused. The touch screen of the printer indicates the amount of powder to be added. This amount is 30% of the remaining powder. Sinterit’s research team is working to reduce this percentage.

Final observations

In retrospect, each individual step was quick and easy to complete, although there are a number of small tasks to complete. This can make the overall process quite time consuming, especially if you have printed multiple designs and/or a complex design.

It should be noted, however, that there is no calibration process to follow. Sinterit pre-calibrates each printer and ensures that each product works before shipping. No adjustments (print bed, laser, etc.) are required.

3D printing results

The model is adapted from the STL file Iris Box from LoboCNC on Thingiverse. We chose it because the object is functional (with moving parts), has some level of detail and thin walls. The box was printed in PA12 with a layer thickness of 0.1 mm.

The result is stunning, with a very clean surface and barely visible layers. Compared to filament based printing, this is really a whole new level of quality.

However, there are a few layers where you can see some “over-sintering”, i.e. where the laser was too powerful. We also had a bit of trouble getting the part to unlock and rotate, but this did not affect the quality of the print.

Below are some images of the piece.

Note: We sent the file to Sinterit prior to our visit, and their designers modified it slightly to fit the SLS technology. The Sinterit team had already tested the printing of the part before our visit.

Value for money: is the Lisa Pro worth it and for which applications?

It’s hard to be objective, but we are really excited about the Sinterit Lisa Pro.

• It is very easy to use. Both the PC software and the Lisa Pro’s touchscreen interface guide the user through the process, and there are no complicated steps (even if the process is long). No special knowledge is required either, but training is offered free of charge by Sinterit and its distributors.
• Depending on your output, the printer and materials can quickly pay for themselves. Our part cost just under €12 to produce, while it would cost an average of about €30 to order online. Being able to reuse the powder also reduces costs.
  The Lisa Pro and its SLS technology offer precise, high-quality parts. We saw this with the part we printed, but also with demonstration parts seen at Sinterit’s facility. In addition, the gray of Sinterit’s PA12 material is attractive and clean, aesthetically speaking.
• The Sinterit Lisa Pro (as well as the standard Lisa) is the only truly available desktop/benchtop SLS 3D printer. For now, at least.

Note: Formlabs announced the Fuse 1 printer in mid-2017, but its launch has been consistently delayed. Swiss manufacturer Sintratec is the only potential competitor to Sinterit, with the Kit and S2. See all the desktop SLS 3D printers here.

The Lisa Pro can be used in many contexts and by almost anyone, from professionals wanting to make high-quality prototypes to companies (from SMEs to large corporations) producing small runs.

It can also be useful in factories and workshops where there is often a need to replace tooling or renew parts.

However, the Lisa Pro and its technology have some drawbacks.

We feel it is important to have a separate work area to prevent powder from sneaking in where it shouldn’t, and because the printer heats up the space around it.
The printer is relatively slow; it takes many hours to get even the smallest prints.
Currently, the range of materials available from Sinterit is limited to Nylon, TPE and TPU. The Lisa Pro is open to third-party materials, but you have to know about them. This opening is mainly intended for research laboratories and universities.
Of course, you have to take a step back and put these elements in perspective. At this price and with such dimensions, the Lisa Pro is a very powerful machine.

Moreover, its limitations regarding materials (at least those officially compatible and available through Sinterit) are more related to the SLS technology than to the printer itself. Sinterit regularly works on new materials. So, this is not necessarily a disadvantage specific to the Lisa Pro, but it is worth knowing.

Note: This printer is not intended for the general public.