Top down dlp 3d printer

1) 2) 3)

1) A platform is placed in the tank with liquid photopolymer, at the same height from the resin surface.

2) The UV laser then selectively cures the required areas of the photopolymer resin according to a predetermined algorithm.

The laser beam is focused on a given path using a set of mirrors called galvos. Then the entire cross-sectional area of ​​the model is illuminated. Therefore, the resulting part is completely solid.

3) When one layer is finished, the platform moves to a safe distance and the mixing foot inside the tub mixes the resin.

This process is repeated until the part is printed. After printing, the part is not fully cured and requires further post-processing under the UV lamp . At the end of UV illumination, the part acquires very high mechanical and thermal properties.

The liquid resin solidifies through a process called photopolymerization: during solidification, the monomer carbon chains that make up the liquid resin are activated by an ultraviolet laser and become solid, creating strong, inextricable bonds with each other.

The photopolymerization process is irreversible, and there is no way to convert the resulting parts back into a liquid state. When heated, they will burn, not melt. This is because the materials that are produced by SLA technology are made from thermoset polymers, as opposed to the thermoplastics that FDM uses.

On SLA systems, most print settings are set by the manufacturer and cannot be changed. The only inputs are the layer height and the part orientation ( last, locates the supports ).

The typical layer height in a SLA print ranges from 25 to 100 micron .

The lower the layer height, the more accurately the complex geometry of the model will be printed, but at the same time the printing time and the likelihood of failure will increase. A layer height of 100 microns is suitable for most common geometries and is the golden mean.

Another important parameter for the operator is the size of the platform. It depends on the type of SLA printer. There are two main types: orientation top to bottom and orientation from bottom to top .

In the first case, the laser is above the tank, and the part is face up. The platform sits at the very top of the resin vat and moves down after each layer is sintered.

In " bottom up " layout on SLA printers , the light source is placed under the resin tank (see picture above) , and the part is built upside down.

The tank has a transparent bottom with a silicone coating that allows the beam of light to pass through but prevents the cured resin from sticking. After each layer, the cured resin separates from the bottom of the tank as the platform moves up. This is called the sintering step.

The orientation " bottom to top " is mostly used in desktop printers like Formlabs. The " top - down " orientation is used in the industrial SLA printer .

Printers SLA " bottom-up " are easier to manufacture and operate, but the size of the possible print will be smaller, since the forces applied to the part during the sintering stage can cause printing to fail.

Top-down printers, on the other hand, can print very large parts without much loss in accuracy. The wide possibilities of such systems naturally cost more.

The following are the main characteristics and differences between the two orientations:

Popular brands:

FORMLABS

Printable area: Up to 145 x 145 x 175 mm

Typical layer height and print accuracy: 25 to 100 µm and ± 0. 5% (lower limit: ± 0.010 to 0.250 mm) respectively

Popular brands:

PRISMLAB

Print area size: Up to 1500 x 750 x 500 mm

Typical layer height and print accuracy: 25 to 150 µm and ± 0.15% (lower limit ± 0.010 to 0.030 mm) respectively

Supports are always required at Print SLA . Structural structures are printed from the same material as the part and must be manually removed after printing.

Part orientation determines the location and amount of supports. It is recommended that the part be oriented so that surfaces that require maximum quality do not come into contact with supports.

In different types of SLA printers, support is used in different ways:

For top - down printers , support requirements are the same as FDM . They are essential for accurate printing of overhangs and bridges ( the critical overhang angle is typically 30 degrees ).

The part can be oriented in any position and is usually printed flat to minimize the number of supports and the total number of layers.

In printers like " from bottom to top " everything is more complicated. Overhangs and bridges also need to be supported, but minimizing the cross-sectional area of ​​each layer is the most important criterion.

Forces applied to the part during the sintering step can cause it to come off the platform. These forces are proportional to the cross-sectional area of ​​each layer.

For this reason, the parts must be oriented at an angle, and minimizing supports here is not a primary concern.

On the left - a detail oriented on the SLA printer "from top to bottom" (support minimization).

On the right is a part oriented on the SLA printer "from the bottom up" (minimizing the cross-sectional area).

Removing supports for an SLA printed part

One of the biggest problems with the accuracy of parts made with SLA is curling. This problem is similar to the deformation in FDM when materials shrink.

During curing, the resin shrinks slightly when exposed to the printer's light source. When shrinkage is significant, large internal stresses develop between the new layer and the previously cured material, causing the part to twist.

SLA printed parts have isotropic mechanical properties. This is due to the fact that one pass UV beam is not enough to completely cure the liquid resin.

Further passes help the previously hardened layers to fuse together. In fact, in the SLA of printing, curing continues even after the printing process is complete.

To achieve the best mechanical properties, parts printed using this technology should be post-cured by placing them in a chamber under intense ultraviolet radiation ( and sometimes at elevated temperatures ).

This greatly increases the hardness and heat resistance of SLA , but does not make it stronger. Rather the opposite.

For example.

materials

Photopolymer resins (thermosetting

materials)

Dimensional accuracy

± 0.5% (lower limit: ± 0.10 mm) - domestic
± 0.15% (lower limit ± 0.01 mm) - industrial

typical size

print area

Up to 145 x 145 x 175 mm - for desktop printers
Up to 1500 x 750 x 500 mm - for industrial

Total layer thickness

25 - 100 µm

Support

Always required

(Needed to make an accurate part)

• SLA print is best for producing visual prototypes with very smooth surfaces and very fine detail.

• Desktop SLA 3 D The printer is ideal for making small, about the size of an adult's fist, injection molded parts. Moreover, such a printer can be purchased at an affordable price.

• Industrial SLA 3 D printers can produce very large parts (up to 1500 x 750 x 500 mm)

Well, that's all we have! Thank you for being with us, see you soon. Further it will be more interesting!

• By phone: 8(800)775-86-69

• E-mail: [email protected]

• Or on our website: https://3dtool.ru/

Don't forget to subscribe to our YouTube channel:

And to our groups in social networks:

INSTAGRAM

In contact with

Facebook

DLP 3D printing | Description and features of the technique

What is DLP 3D printing?

DLP 3D printing is an additive manufacturing technique that uses liquid photopolymer resins to build objects that are cured by light waves. “Yes, this is an SLA print!” - exclaim those who are already familiar with the methods of additive manufacturing. Indeed, the principle of operation of these two technologies is almost identical. However, the curing of the object in DLP printing occurs under the influence of a different light source.

In general, DLP 3D printing can be described as a direct analogue of SLA 3D printing, in some aspects even superior to it. For example, the print speed in DLP 3D printers is an order of magnitude higher than in SLA devices. And the difference in fidelity varies depending on the specific equipment and consumable, and is generally small. Now let's move on to the technical aspects and talk about the principle of operation of DLP technology.

Technology Description

As with all 3D printing technologies, the first step in manufacturing a physical object is to create a 3D digital model of it. We will not delve into the details of this stage, you can read more about 3D modeling for 3D printing here. The finished 3D model is loaded into a slicer program designed to set print settings and “cut” the model into layers. This step also generates supporting structures under the overhanging elements of the object. The received settings are saved, the model is converted into a control code for a 3D printer. Now you can start printing.

Above, we mentioned the similarities between DLP and SLA 3D printing. It's time to talk about their difference and how DLP printers work. Instead of a laser machine (as in SLA), DLP 3D printing works with a special projector as a light source. This technique is not new: you can also find such DLP projectors in other, more common devices, for example, in TVs. Here they are also used for curing liquid consumables - photopolymer resins.

As in SLA printing, there are two options for DLP 3D printing devices: in one, the object is built from the bottom up (the working platform goes down), and vice versa (the working platform goes up). In our article, we will consider DLP 3D printing using both types of devices as an example.

Reverse DLP 3D printing

So, a special container of a 3D printer is filled with photopolymer resin to a certain level. The building platform is lowered into the container so that the gap between it and the bottom is equal to the height of one layer. Under the tank is a DLP projector. Light corresponding to the section of the first layer of the model is projected onto the platform. After its curing, the platform rises and the illumination of the second layer begins.

So, step by step, a physical object is created. Upon completion of printing, the platform rises above the level of the photopolymer, the product is removed and cleaned of the remnants of the consumable. After that, it is necessary to perform the final illumination in a UV lamp for complete curing of the material.

Direct DLP 3D printing

In contrast to reverse printing, the DLP projector is located on top, above the resin tank. In this case, the working platform is located directly in it. To build the first layer, the platform rises so that the gap between it and the surface of the consumable corresponds to the height of the first layer.

The cross section of the first layer is projected onto the platform, curing the photopolymer, after which the platform is lowered down to the height of one layer. These steps are repeated until the complete construction of the product. Further actions are identical to those described in the previous paragraph: the object is removed, cleaned of consumables and subjected to additional illumination.

Benefits

Why is DLP 3D printing so interesting? What features of it help this technique to gain more and more popularity every day? Let's watch:

• Faster print speed than SLA 3 D printers. Unlike laser stereolithography, DLP 3D printing projects an entire layer onto the photopolymer at once, and does not gradually pass through its sections with a laser. Due to this, the speed of creating products increases several times;
• High print precision. In terms of the accuracy of the created objects, DLP 3D printing is in no way inferior to SLA 3D printing: the layer height in this technique can reach 15 microns! However, it all depends on the type of 3D printer and the specific material;
• Large selection of consumables. As for photopolymers, their range in the 3D printing market is so wide today that it is sometimes difficult to decide. Moreover, often DLP 3D printers can work with the same consumables as SLA printers;
• Affordable equipment price. DLP projectors are much cheaper than laser systems, which affects the cost of 3D printers for DLP printing for the better. Technology is developing rapidly and many today are opting for digital LED projection.

Among the shortcomings, it is worth highlighting only the rather high cost of consumables.

Materials used

DLP 3D printing works with liquid photopolymer resins (much the same as SLA 3D printing). Some consumables are even suitable for both methods. It depends on the wavelength of illumination and consumables. However, even specifically for digital LED projection, excellent professional lines of photopolymer resins have been developed.

So, today in the 3D printing market you can find flexible and rigid materials, transparent photopolymers and resins of a wide variety of colors. Consumables for specific applications are also available. For example, dental photopolymers with various properties, as well as burnable materials for the manufacture of jewelry master models.

Equipment

Even today, some DLP 3D printers can compete directly with SLA printing equipment. Our store presents a variety of devices, both professional and budget class, for DLP 3D printing. Some of them are listed below:

• WANHAO DUPLICATOR 7
• M-ONE
• WANHAO DUPLICATOR D7 PLUS
• B9CREATOR
• TITAN1

All 3D printers are available for order.

Learn more

• 
  Diy moon lamp 3d print
• 
  3D print living hinge
• 
  Lathe 3d printer
• 
  Best 3d printer industrial
• 
  3D printing advancements
• 
  3D printer compatible with autodesk inventor
• 
  3D scanner and printer in one
• 
  Can a 3d printer catch on fire
• 
  3D printer merchandise
• 
  Makerbot replicator z18 3d printer price
• 
  3D print toy car