DLP technology. Digital LED Projection (DLP)
A series of articles on DLP printers. It would be more logical to start with general principles work, but the article about the projector seems to me the most relevant, because... questions constantly arise about them. In addition, this is the most important and expensive part of a DLP printer.
So, a projector for a DLP printer should, unexpectedly, be of DLP technology. This is due to the fact that the spectrum of radiation to which the polymer photoinitiators react and the radiation spectrum of the projector have a very small area of intersection. The efficiency is very low. In DLP projectors, the spectrum contains a certain amount of soft UV radiation, which, coupled with violet (wavelengths approximately 390-410 nanometers), at the very least hardens polymers.
In alternative 3LCD technology, lamp light passes through LCD matrices and a block of massive glass prisms, which reduce the already narrow spectrum useful to us.
Next is critical important parameter - brightness. The brightness of projectors is measured in ANSI lumens (ANSI method for measuring these very lumens, the Chinese may have their own - Chinese, so be careful with them).
It is believed that a printer projector must have a brightness of at least 2700 lumens. The limit is somewhat arbitrary, but in general I recommend sticking to it. In general, it is better to look at the power of the lamp. From 190 W and above is our option. We see that LED projectors are just passing by.
A small hole in the wilds
In theory, the more lumens, the faster the polymer should cure.
However, there is an opinion that with the same lamp power there is no difference between a projector of 2700 lumens and 3100 lumens, or it is negligible. Manufacturers are chasing lumens and resorting to various tricks to inflate these numbers. The fact that we managed to increase the overall brightness white, does not at all guarantee that the power of the spectrum region of interest to us will increase.
Contrast. It would seem that everything is simple here, this is an attitude maximum brightness projector to minimum. The maximum brightness is achieved when displaying white, and the minimum when displaying black. According to the ANSI method, measurements must be carried out on one frame. However, in pursuit of numbers, manufacturers measure differently. Modern projectors have a dynamic contrast system that reduces brightness in dark scenes, making blacks as deep as possible, and increases brightness in bright scenes. Manufacturers calculate the ratio of the maximum brightness in a bright scene to the minimum brightness in a dark scene, obtaining cosmic contrast values in the tens of thousands. For us these are dead numbers. Since it is impossible to know the real contrast value in one frame without special equipment, all that remains is to adhere to the rule, the more the better. It’s better not to bother with this parameter at all.
Permission. It is important to differentiate between projector resolution and printer XY resolution. The projector's permission is given to it once at birth. Standard values 800x600, 1024x768, 1280x800, 1920x1080 pixels. You need to look at your own resolution, and not at the maximum supported one!
The XY resolution of the printer depends on the projector resolution and the size of the work area. Those. A resolution of 50 microns (pixel size) can be achieved by both a 1024x768 projector and a 1920x1080 projector, only in the first case Workspace will be only 40x30 mm, and in the second 96x54 mm.
DPI Calculator will help you calculate the size of the print area and the corresponding resolutions for a specific projector
Of course, the higher the native resolution of the projector, the cooler the printer will be. I recommend using projectors with a resolution of at least 1024x768.
Connectors. From the point of view of printer manufacturing, it is absolutely not important through which interface the projector is connected. You can safely connect via VGA; this is more than enough to output individual frames.
There is one more connector that may be useful to us. This is RS232. Creation Workshop's popular DLP slicer allows you to control the projector through this interface. For example, you can configure automatic shutdown projector after printing is complete. If you plan to use it, you need to make sure that the projector has a standard RS232 DB9 connector. On my combat Acer P1273, some vile pervert pulled the following dirty trick:
Not just a cable, but a plug is a whole quest to find. So be careful. Fortunately, most projectors use regular DB9s.
According to the main parameters, everything seems to be fine.
Focusing the projector. Most projectors out of the box cannot focus on the area we need. The exception is short throw projectors. But they have a number of disadvantages. They are more expensive than a regular projector with similar characteristics. It's much harder to find used ones. And most importantly, it is not clear what specific XY resolution can be obtained on this model of short-throw projector.
Conventional projectors require modifications.
The easiest option is to use an additional lens. Alas, even a well-chosen lens introduces inevitable distortions, so this is a completely amateur option. Although for simple tasks it will do.
A more complicated option is to unscrew the locking screw (or remove the strap on some models) of the lens. This will allow you to unscrew the lens an extra half turn. Sometimes this is enough. If not, then you will have to make an “extension cord”.
I've already talked about this in detail.
Unfortunately, there is another lens option, the thread on which is much more difficult to increase (the lens is located at the bottom of the thread and there is simply nowhere to insert the adapter). I've seen "light" lenses on Acer and Benq. "Complicated" on ViewSonic and Infocus. How to find out which lens is in it without opening it specific model, I don’t know yet, unfortunately.
One more thing. When remaking a lens, it is better to take models in which the focus wheel is located on the lens (like on the Acer P1273) and spaced apart from the zoom lever:
In models where focus and zoom are combined, after installing the extension, the knobs no longer fit together normally and you have to modify them somehow:
Other modifications(which I don't approve of). There are several ways to increase the effective brightness of a projector.
Removing the UV filter. This filter is a piece of glass that cuts off a certain amount of radiation that is useful to us. Some instructions recommend removing it. The problem is that this glass is part of the cooling system (perhaps in some models this is not the case). Those. if it is simply removed, there will be a hole in the duct and the air flow will change. One can only guess how this will affect the lifespan of the DLP chip. It is not possible to replace the filter with ordinary window glass - it does not withstand it and cracks. Those. To smartly get rid of this filter, you need to replace it with some kind of heat-resistant UV-transparent glass. Modern polymers allow you not to bother with this.
Breaking the color wheel. It is irreversible breaking, because If you simply disable it, the projector will not pass the startup self-test and will not turn on. In my opinion, a senseless act of vandalism.
Apparently, the roots of this “modification” should be sought in the days when DLP projectors had a three-segment color wheel, on which up to 60% of brightness was lost when outputting white, and getting rid of it made sense. Nowadays, a 6-segment color wheel with a transparent sector has been used for a long time to achieve 100% brightness. Therefore, I doubt that such an operation will have a noticeable effect. Although I haven't tried it myself. If anyone has personal experience, unsubscribe in the comments.
In general, I would not recommend messing with models before 2013 (conditional limit). Of course, there is a temptation to buy a “dinosaur” on eBay for 10 bucks, but it’s better to save your nerves. In older models, childhood technology diseases such as insufficient black depth or uneven brightness are more pronounced.
Everything seems to be okay with the main points. If you forgot anything, ask in the comments.
If you have questions about purchasing 3DLab Basic polymer, please write in a personal message. For other questions you can too.
Good luck!
DLP technology – high level of printing
First, a little about herself
DLP technologies. Decrypts-
xia she as Digital Light Processing
(digital light processing) and was
was invented back in 1987, and
more precisely, the chip was invented,
who made this possible. And even
now a Texas Instruments company
and inventor of technology Doctor
Dr. Larry Hornbeck
own a huge amount of pa-
tents for technology.
Actually, what kind of animal is this?
such? DLP is simply one of the most
common types of projectors. We encounter projectors many times during the course of
life, from going to the cinema to a school presentation. But we can’t help but ex-
change when it comes to such a magical field as 3D printing. Therefore, even though he
initially and was not suited for such a role, it began to be actively used to reject
photopolymer and now it can even be found in printers from 3D Systems, which is confirmed
There is no professionalism in its use, despite the non-obviousness of the design.
What makes projector stereolithography stand out? Often, as a “plus” argument, speed is given.
Printing speed: since the entire layer is illuminated, the process is often somewhat accelerated.
However, the rule does not always work: printing speed depends on a huge number of factors, such as
that it is better to focus on the information left by the manufacturer.
SLA
Stereolithography (SLA) is one of the most common methods for additive manufacturing of 3D models. Principle this method consists of ultraviolet radiation, which, when it hits a layer of photopolymer resin, makes it hard. This technology has found widespread use among professionals. But until recently, not everyone could afford such technologies, since it is quite an expensive pleasure. The most expensive are laser emitters. Now such a printer can be purchased at a price of 170,000 rubles.
DLP as a better alternative to SLA
The DLP method is an alternative to SLA. Instead of laser installations Light projectors are used, which cost much less, and, accordingly, the cost of the 3D printer itself is reduced. In SLA technology, scanning occurs using one or more heads, printers 3D DLP in Chelyabinsk projects an image of the entire layer until it is completely cured. After the layer has hardened, the next layer is applied and so on until the very end, until the object is ready. 3D printers in Chelyabinsk, working using DLP technology show high results in accuracy and quality and are in no way inferior to the original stereolithography technology.
Moreover, DLP printers are a big competitor to SLA printers. DLP technologies are widely used in dentistry, mechanical engineering, jewelry industry, design and production of souvenirs.
Pros and cons of DLP technology
3D printers using DLP technology have a number of advantages and disadvantages. Which advantages of DLP printers?
- High quality;
- Accuracy;
- Photopolymer is a construction material that has wide range mechanical characteristics, and can be either hard or soft;
Disadvantages of technology:
- High cost of photopolymer resin;
- Higher accuracy can only be achieved by reducing the printing speed. In other words, the more precisely an object is needed, the slower it will be reproduced.
However, despite some shortcomings, this technology has proven itself very well and has found wide application among professionals and 3 Dprototyping. Thanks to it, you can recreate the most complex designs, the most small parts. And the resin, which is the basis, is environmentally friendly and quite durable. Therefore, finished products will last for a long time and will be as realistic as possible.
In mid-2014, the development of the line of high-precision professional 3D printers Starlight 3D and Russian DLP was completed in St. Petersburg.
Starlight 3D is professional solution for jewelry, dentistry and other areas where the highest precision of models is required, which it can well provide, and Russian DLP is aimed at training, hobbies and 3D printing enthusiasts.
The declared characteristics are very ambitious: a layer thickness of 20 microns is enough to print master models of jewelry, dental models, and engineering prototypes with the highest accuracy. Maximum resolution along the X and Y axes it has a respectable 45 microns.
We tested the Russian DLP 3D printer and interviewed its creator.
Equipment and technical characteristics of Russian DLP
Of the presented technical characteristics The only thing that's a little underwhelming is the print area, which is 96x54x180mm. Optionally, it can be increased to 144x81x180mm by installing an additional surface for building up the part (substrate).
Russian DLP comes in a hard wooden box large sizes. Packed and fastened securely, so there should be no problems or damage during transportation.
The package includes: the printer itself, cables for connecting the printer and projector, a disk with software, user manual and others useful little things, polymer bath and photopolymer itself in a volume of 1 liter.
The printer is equipped with a Vivitek DLP projector with FullHD resolution and increased lamp life, which is very important detail for a 3D printer - exposure of models can take a very long time long time, and a high lamp life will help reduce printer maintenance costs to a minimum.
Overall dry Technical information this is, of course, great, but what is much more interesting is how the printer behaves in operation: how easy it is to use, reliable, stable, and most importantly, what is the quality of the resulting parts.
Appearance
The design of the printer is as simple as possible - an open frame, in the lower part of which a projector is mounted on a movable frame, in the upper part there is a working chamber, closed with a red transparent body. The substrate screw and logo illumination are made in red. All together it looks stylish and enhances the impression of the simple design of the entire printer.
The guides, stepper motor, and lifting table are visible and open for maintenance and service.
Behind working chamber there is control electronics hidden in a solid housing.
Perhaps one element that requires extremely careful handling is the photopolymer bath. The film that is on its glass is quite thin, and damage to it and the ingress of resin will put an end to your print. So you need to be very careful when cleaning the bathtub.
There are very few controls on the printer itself - on/off, reset and platform height buttons. All other control is carried out using a computer connected to the printer. Of course, there are still controls on the projector, but more about them later initial setup, you can forget.
Software
The disk contains all the files and programs necessary for printing: a printer driver, sequences (a set of images for each layer) for cleaning, various support files, a user manual and two of the most important programs: Creation Workshop and RussianDLP Print Manager.
Creation Workshop is a slicer program for SLA and FDM printers. It features convenient manual placement of various supports and adjustment of their shape. At the output, it exports the model as a sequence of images, which is transferred to RussianDLP Print Manager. All settings sent to the printer are set here - exposure time, layer thickness, lifting speed and others.
Overview of processes and print quality
Let us immediately note that out of the box the printer requires some setup and calibration. Most of these settings do not need to be made later, and printing will start much faster.
If the same photopolymer is used and the printer has not been transported, then no additional manipulations other than slicing will be required before printing.
Every the new kind photopolymer requires its own settings for layer thickness, exposure time, and exposure time for the first layers. But the abundance of settings also means a large number of proprietary resins used:
Fully burnable jewelry photopolymer
Technical photopolymer
Ceramic photopolymer
By the way, distinctive feature of these materials is that their cost does not depend on currency fluctuations and they are all produced in the Russian Federation.
We decided to test it for work in jewelry, as the field that is most demanding in terms of model accuracy. Let's check it by printing two copies of rings with rather complex geometries. The model contains many holes measuring about 0.5 mm. In this case, the included resin of our own production, Starlight, red in color, was used.
For printing, we used the following settings of the Russian DLP Print Manager program:
We connect to the printer and start printing. The first printing went without any problems: the model was perfectly attached to the substrate and was printed successfully. The small holes are filled with resin, but this can be solved by spraying the model with alcohol from a spray bottle. The holes are cleaned, we send the models for final polymerization in an ultraviolet chamber, and evaluate the result.
The rings turned out just perfect. The smallest details are worked out, the drawing on them is also very detailed, there are no layers at all, either to the touch or visually. The printer fully justified all its stated characteristics. The resin is quite flexible, the surface is glossy. By the way, the cost of each polymer ring was about eight rubles.
For comparison, we printed the same ring on the same price range Formlabs The Form 1+ printer and compared the results. 
Here Russian DLP won in print quality: the thin mesh turned out much better, unlike Form 1+. Another advantage is the number of supports: the Form 1+ slicer generated them in a huge number, which will cause problems during post-processing. In CreationWorkshop, which uses Russian DLP, supports can be set manually, and much less of them are needed. And one more plus to Russian DLP - thanks to the specially shaped substrate, the required substrate thickness is much smaller, which significantly saves photopolymer and reduces the cost of printing.
During the preparation of this article, the manufacturer managed to print a ring on the Starlight burnable photopolymer released just a few days ago and showed the quality of its burning.
The casting result is simply excellent, the detail of the model is extremely high and the metal ring looks great. To summarize, we can say that even the youngest model in the line confidently ensures high-quality execution of models for jewelry.
Conclusion
The printer definitely deserves attention. Being one of the cheapest models in its class, it provides print quality that is not inferior to competitors.
Of course you need it preliminary preparation, willingness to experiment and knowledge of 3D printing methods, but you will get the appropriate result. At the same time, the printer is reliable; all elements subject to wear are made well and can be easily maintained if necessary.
We couldn’t help but take advantage of the opportunity and did a short interview with the creator of domestic 3D printers Starlight 3D and Russian DLP about his developments and plans for the future:
Printing 3D models is still new, and many people still don’t understand what it is, how it works, and what it’s for. 3D printing – useful technology, facilitating the work of specialists in many industries.
Understanding 3D printing and DLP
3D printing emerged as a prototyping method. Prototyping is the creation of a model in material form. First, a 3D model is created. Then it must be manufactured in the material. This is necessary to illustrate the idea of the future product and to conduct tests. Prototyping was enough challenging task until it appeared Rapid technology Prototyping – rapid prototyping.
Before the advent of rapid prototyping, the design had to be made by hand. Modeling, turning on a machine, and so on - all this is a rather lengthy process that takes time. Accordingly, the efficiency of the entire production is lost. Devices that came to be called 3D printers solved this problem. The layout is created quickly and is a high-quality model.
3D printer is a device for layer-by-layer creation real object based on a three-dimensional model created on a computer by the relevant software. There are several technologies. Some of the most effective are devices with a DLP projector.
Digital Light Processing (DLP)– digital projection technology based on the use of microscopic mirrors. It has wide use in many areas, for example, in medicine.
LED projection in 3D printing is the main competitor to SLA - laser stereolithography. SLA is widespread, but has high cost, due to the use of laser. These methods are called additive.
How DLP works
DLP devices are based on the use of mirrors. The microelectromechanical system creates an image by controlling mirrors that are located on a semiconductor chip. The principle of operation of mirrors is similar to digital code consisting of zeros and ones. In this case, the unit is the reflected light when it falls on the mirror, and the zero is the absorbed light when it falls on the radiator. The mirrors are quickly positioned, allowing you to control the light intensity and add shades to the image.
According to the program set three-dimensional model, light is directed onto areas of the printed material. When exposed to light, the substance hardens. One after another, layers of the product are formed. In other words, the printer “grows” the object.
The minimum layer thickness when using DLP is very small - 10 microns. This is the best accuracy rate among 3D printers. The printing speed is also higher than that of technologies such as FDM, SLA, SLS.
Materials for 3D printing using digital LED projection technology
For 3D printing, the most different materials, from metal and concrete to chocolate. With the development of 3D printing, the number of materials suitable for this is also increasing. Thanks to this, they open the broadest opportunities in production.
For additive printing methods, only photopolymer resins are used. These are liquid polymers that are sensitive to ultraviolet radiation. The limitation of materials is due to the fact that the substance must harden under the influence of rays. It is clear that metal or chocolate is not suitable for this.
However, LED printing is used effectively. This is one of the types of printers that are quite suitable for home use. Photopolymer products are highly durable. The only downside is the cost Supplies– finding cheap photopolymer resins is difficult. The printers themselves already have reasonable prices.
DLP 3D printer design
The design of such printers is not too complicated. They usually consist of a platform, a DLP projector and a container of liquid. Initially, the platform is near the surface of the liquid. The first layer is projected, after which the platform rises. The procedure is repeated until the product is ready.
Commercially available printers may differ in their design. Some of them have a platform that goes down rather than up. Solutions are being created with different volumes of photopolymer containers and platform sizes.
Application and prospects
The most obvious application of 3D printing is rapid prototyping. The advantage of this method over subtractive (removing excess) has made 3D printers popular among designers and engineers.
Advances in technology have made it possible to use 3D printing for simple mass production. This can significantly simplify and reduce the cost of many industries. Additive technologies are quite promising in this regard. One of the problems is the printing speed is insufficient for mass production.
Developments are underway to use 3D printing technologies in medicine. Developments in the use of organic materials can bring significant benefits. For example, there are already some results on printing bioimplants.
A promising direction is printing electronic devices. Undoubtedly, this technology is more complex than layer-by-layer “growing,” but it was difficult to think about the capabilities of 3D printers recently.
3D DPL printers are most widespread among hobbyists. You can create amazing things with these devices. beautiful gifts and souvenirs.
Advantages and disadvantages DPL printers
To the advantages DPL printers boast high printing accuracy and speed. Digital projection technology in general is very useful, as evidenced by its application in many areas. It is always important to pay attention to the future, and 3D printing has not yet revealed its full potential. Another advantage of these DLP devices is their lower cost than other printers.
To the disadvantages can be attributed to the material used. The issue is the safety of the materials used. There are quite toxic polymer resins. And they are also quite expensive. But the results fully compensate for these shortcomings.
Hi all! I want to tell you about my hobby - building DLP 3D printers. I first heard about stereolithography technology when the B9Creator printer was released on KickStarter, since then I became interested and began to study this topic. At first glance, the technology itself is quite simple, just one axis with a platform on which a light-sensitive material - a photopolymer - is cured layer by layer using a projector or laser, but the complexity, as it turns out, is in the details. There are two main problems with stereolithography: separation of the layer from the bottom of the polymer bath and precise focusing of the light flux.
Layer separation
To begin with, I would like to dwell in more detail on the first problem. After curing, the photopolymer adheres very strongly to all surfaces. Additionally, when the model is torn off from the bottom of the bath, there is a suction cup effect (due to vacuum and the viscosity of the polymer), therefore, in addition to the anti-adhesive coating, there must be something in the layer implementation system that minimizes this effect. I would highlight the following main approaches to layer separation:
1. Shift with level transition. The bathtub is a two-level container; the model moves from one level to another (lower). There can be either a slider or a rotational movement. Used in B9Creator, Autodesk Ember printers
2. Tilt (inclination) of the bottom of the bath. This species can also be divided into 2 subspecies:
- the so-called passive tilt. An approach in which the tilt of the bath is caused by the model itself, i.e. the model stretches upward and pulls the bottom of the bath, which is either on the axis of rotation, or on springs, or is simply deformed, eventually unsticking. Special case This approach is a flexible (Flex) bath. It is used in many printers due to its ease of implementation; among the well-known ones I can name Kudo Titan 1.
- tilt, which is created by an additional motor. Used in Form 1, Envisiontec and many other printers.
3. Two Z axes, first one side of the platform rises, then the other. Among the famous printers I can name Solidator.
I started my construction with the first approach, in the image and likeness of the open source B9Creator. The result was my first 3D printer, this garage beast:
It printed quite well, and for a long time I did not look for alternative approaches, but later I identified the following disadvantages:
1. The plane of movement of the slider must be ideally parallel to the plane of the layer, otherwise, when shifted, the bottom of the bath will catch on the model and displacements, artifacts, etc. will occur.
2. Even with perfect parallelism, during shear there is a lateral load due to friction on the bottom and due to the viscosity of the polymer; as a result, thin elements (especially if the polymer is not strong enough and highly viscous) will be broken off or shifted, which will lead to a “dirty” surface or no typos.
3. It is difficult to use any other anti-adhesive substances other than organosilicon silicone (PDMS). Organocrenic silicone itself is good as a release coating, but it quickly becomes cloudy, as a result it requires frequent replacement, which is inconvenient. Silicone also scatters light greatly (especially thick layers), resulting in reduced detail.
I decided to try the second approach, passive tilt using Teflon at the bottom of the bath due to the ease of implementation. But one thing bothered me was that the load upon lifting is still very large, because the model pulls the entire weight of the bathtub. With this approach, models often fall off the platform; thicker supports are needed. Therefore, so that the weight of the bathtub did not fall on the model, I made a steel frame with magnets. Before the limiter, the frame was pulled by magnets and pulled the bathtub up with it, after the limiter the bathtub was tilted, and the model with continued to move upward. It looked like this (the second garage beast): Later, this printer was modified a lot, a new, more powerful frame, linear rail guides, and a normal axis of rotation of the bath were installed, but it was not possible to achieve a clean surface. Until I finally understood the whole main flaw of the passive tilt approach, I’ll try to explain it with pictures.
Those. The bottom of the bath, when rotated in the direction of movement of the platform, creates an additional lateral load, resulting in a dirty surface of the model. In comparison, the tilt of the bathtub away from the model where this problem does not arise:
In general, this problem can be solved if the bottom of the bath is as flexible as possible (much more flexible than the cured polymer). The so-called Flex Vat, bathtubs with a Teflon (fluoroplastic) flexible bottom, have just begun to appear on foreign thematic forums. And I decided to create my own version. The first thing I came across was that the fluoroplastic film has a tension threshold; after a certain force it stretches. Accordingly, the thicker the film, the stronger it can be stretched, but the main thing is that this does not compromise transparency and the shock-absorbing effect. As it turned out, if the bathtub is large, even with the maximum stretch of the film, it will still sag under the weight of the polymer and the pressure of the platform from above as a result of distortion of the geometry and non-printing. I tried to make a supporting bottom on which the film is stretched, while the film can bend upward, but from below it does not allow the plexiglass bottom to bend. But this approach stops working after the first wash of the bath and moisture gets between the film and plexiglass, the film sticks to it due to vacuum forces and the entire shock-absorbing effect is eliminated. So I decided to make 2 baths, one for detailed models with high resolution and thin elements, in the printing area there is only 0.1mm fluoroplastic film, the rest of the area is supported by a plexiglass flange. Second bath for volumetric models and lower resolutions, the bottom of the bath is entirely made of 0.5mm PET, over which a fluoroplastic film is stretched, a compromise between the shock-absorbing effect and the ability to sag due to the weight of the polymer and the pressure of the platform. The bath looks like this:
But since for large surfaces the shock-absorbing effect on the second bath is minimal, I decided to add an active tilt of the bath to my printer, and the use of a flexible bath and tilt at the same time creates an even more “gentle” separation of the model from the bottom of the bath. Well, you can always choose one of the release methods or use both at once, plus, with a sufficiently amplitude tilt movement, it is possible to discard the reciprocating movements along the Z axis and pull the model out of the bath “pull”. This time I decided to do everything “right” and sat down to develop drawings in SolidWorks. I planned production by laser cutting and bending 3 mm aluminum, I didn’t think much about the design, the main thing was the simplicity of design and assembly. I made a logo and came up with an “original” name :). The result of the development was this pepelats:
Well, after some time I assembled the final version (15-inch laptop for scale):
Next I want to talk about the second problem, this is focusing the projector into a spot of light with a pixel the right size. Because I planned to catch up and overtake Envisiontec :))), then I wanted to focus the projector into a spot of light with a pixel of 25-30 microns (XY resolution). Naturally, no commercial projector with a standard optical system will focus like this, so modification is required. There is most likely no universal recipe here, but every projector has a zoom wheel that moves the zoom lens, here our task is to “untie” the lens from the wheel and move it to the place we need, which is what I did for my projector. Clarity, as I already wrote, is influenced by many things, the turbidity of the bottom, its thickness, the material from which it is made, from my own experience I will say that I got the best detail on bare stretched fluoroplastic film. Next, the focusing process itself is important, I recommend doing this with dark glasses (the lines are much more clearly visible) and something (usually a paper template for calibration) should be placed on the surface of the bath, because often the eye sees refracted light on the lower surface of the bottom of the bath, but you need to focus on the top surface.
Software
I used the source code of the B9Creator 1.6 software, distributed under GPL license v3, fortunately I understand a little C++. The module for arranging supports and slicing into layers remained virtually unchanged; the printer control was adapted to its firmware, support for an alignment mask was added, as well as for the ability to place supports and slicing into layers in Creation Workshop, and a CWS file converter was added. As required by the GPL, I also post a compiled win32 version
Bottom line
Everything described above is just my personal experience, I don’t pretend to be true.
As a result, the printer turned out to have the following characteristics:
XY illumination resolution: 25-50 microns
Positioning resolution in Z: 10 microns (without microstep, respectively 5, 2.5 .... etc. microns with the step crushing mode enabled)
XY print area dimensions: 48 x 27 mm (at XY point 25 microns), 96 x 54 mm (at XY point 50 microns).
Building height: up to 200mm.
Well, photos of printouts
On an electron microscope, model M4, printed on EnvisionTEC Perfactory Aureus (printer costing 2.8 million rubles), polymer RCP30 (40-50 thousand rubles per kg) and next to my version (30 microns XY, 20 microns layer) polymer MaikerJuice (3 -4 thousand rubles per kg).