FAQ - DLP “Digital Light Processing” technology. Professional 3D printers using resin polymerization by means of light projection. - SISMA


What are the differences between DLP and Laser SLA?

DLP (Digital Light Processing) stereolithography print technology is based on a digital light source (projector), emitting in the UV spectrum, able to polymerize layers of photosensitive polymeric resin. Unlike DLP, SLA laser technology is based on a UV laser source that irradiates photosensitive resin. The use of a DLP projector allows the polymerization of every layer in a single instant, which cannot be done with laser, as the latter has to trace an outline on the entire layer to be polymerized. This means that laser printing takes much longer, and they tend to increase as spot laser decreases, thereby creating a compromise between speed and productivity; this compromise does not exist for DLP technologies, as printing speed is not affected by resolution.
EVERES printers use proprietary SISMA EVERES resins only. Other third party materials do not qualify and are not compatible with the machine.
Thanks to the digital light processing (DLP) technology used by EVERES, printing time is not dependent on the number or size of the printed elements, as every single layer is printed in a single instant. Hence, the only parameter affecting printing time in DLP technologies is the height of elements along the Z axis. As in all 3D printing techniques, the more work develops along the Z axis, the higher the number of layers that will need to be generated and as a result the longer it will take to complete the task.
Before launching a project with EVERES, the user should first consider the placement and orientation of the element on the printing base. This can be managed both automatically and manually with the SISMA EVESOFT proprietary software. With the stereolithographic printing technique, an element may require supporting for reasons of dimensional stability of the printed piece; this aspect can also be managed by EVESOFT, which provides an automatic support system. This type of support can also be controlled manually, by adding, removing or changing the types of supports and related connections.
EVERES Smart Building Platform allows the automatic detachment of the printed product, with no manual intervention on the platform required. Once removed, the piece may be cleaned from excess resin in a isopropyl alcohol bath, adding ultrasounds if required, to ensure more effective cleaning. Next, the supports may be removed from the piece with the specifically designed tools supplied by Everes. Finally, the printed element should undergo post-curing within a dedicated unit, according to the instructions included in the technical specifications of the resin used.

EVERES needs no manual resetting before printing. At the start of every printing task, EVERES automatically self-aligns the print base on the bottom of the printing tank. Once completed, the print base is locked in and remains aligned until the task is complete.

EVERES can manage the resin automatically at each printing cycle. During the preparation phase, a quantity of resin sufficient to carry out the selected task is automatically poured into the work chamber. At the end of the task, any excess resin will automatically be withdrawn inside the original cartridge, for optimum storage with no waste. Additionally, according to the type of resin used, users can select the thickness of layers with which they intend to build their model using the EVESOFT software. This setting may be changed manually and is the only one that users should consider when choosing the material, as the machine will automatically load the process parameters simply by placing the resin cartridge in the appropriate housing, thanks to RFID technology.

All EVERES printers connected within “My local network” can be controlled by EVERES Monitoring Interface. This browser interface shows the status and printing phases of the units in the network, it also allows the management of the basic functions of the EVERES hardware (SBP, Hydraulic System, Tilting Glass and Door) to perform all standard printing operations. EVERES Monitoring Interface is a browser interface, hence it can easily be managed from any connected device, i.e. PC, tablet or smartphone.

All Bottom-Up Stereolithography techniques are affected by a mechanical effect on the printing element, the so-called “suction cup effect,” due to the hydrodynamic properties of the resins used. This effect may be reduced with Zero Tilting Glass technology, patented by SISMA, combined with the PTFE membrane placed on the bottom of the printing tank. Zero Tilting Glass technology provides a mobile glass layer beneath the tank, which is automatically lowered every time the platform moves upward. This minimizes mechanical resistance, which will thus be due to the PTFE membrane only, hence minimized. Besides, the material that makes up the membrane is totally inert and will not degenerate when exposed to UV light and the resins used; as a result, this membrane is long wearing and the tank will not need to be replaced frequently.