rus
Issue #5/2022
D. S. Trubashevskiy
Eppur si muove or Forget Everything You Knew About Classic 3D Printing
Eppur si muove or Forget Everything You Knew About Classic 3D Printing
DOI: 10.22184/1993-7296.FRos.2022.16.5.358.368
The main goal of additive manufacturing (AM) is to significantly increase the full-scale production capacity. The dynamic development of additive technologies (AT) is related to the prospects for its automation when integrating into the machine designs of the modular layout arrangements. The layouts are considered where the workbench is an important element for production automation and performance improvement of the entire process system. The usage of a round table with polar coordinates can affect the AM capacity. Various ATs are considered, including MJM, STEP, MoldJet, HSR, in order to demonstrate application of such workbenches.
The main goal of additive manufacturing (AM) is to significantly increase the full-scale production capacity. The dynamic development of additive technologies (AT) is related to the prospects for its automation when integrating into the machine designs of the modular layout arrangements. The layouts are considered where the workbench is an important element for production automation and performance improvement of the entire process system. The usage of a round table with polar coordinates can affect the AM capacity. Various ATs are considered, including MJM, STEP, MoldJet, HSR, in order to demonstrate application of such workbenches.
Теги: 3d printers 3d printing 3d printing of electronic components 3d-печать 3d-печать электронных компонентов 3d-принтеры additive manufacturing additive technologies automation cartesian reference system full-scale production multi-materiality piezoelectric heads polar coordinate system robotic process automation rotational 3d printing wearable electronics автоматизация аддитивное производство аддитивные технологии декартовая система координат мультиматериальность носимая электроника полярная система координат пьезоэлектрические головки роботизация ротационная 3d-печать серийное производство
Eppur si muove
or Forget Everything You Knew About Classic 3D Printing
D. S. Trubashevskiy
Modern Equipment LLC, Moscow, Russia
The main goal of additive manufacturing (AM) is to significantly increase the full-scale production capacity. The dynamic development of additive technologies (AT) is related to the prospects for its automation when integrating into the machine designs of the modular layout arrangements. The layouts are considered where the workbench is an important element for production automation and performance improvement of the entire process system. The usage of a round table with polar coordinates can affect the AM capacity. Various ATs are considered, including MJM, STEP, MoldJet, HSR, in order to demonstrate application of such workbenches.
Keywords: additive manufacturing, additive technologies, 3d printing, 3d printers, automation, robotic process automation, full-scale production, cartesian reference system, polar coordinate system, multi-materiality, piezoelectric heads, rotational 3d printing, 3d printing of electronic components, wearable electronics
Received on: 05,07.2022
Accepted on: 04.08.2022
INTRODUCTION
Like many wonderful legends without any facts and evidence, at present a phrase “Eppur si muove! Albeit it does move!” erroneously attributed to Galileo Galilei has firmly taken root in the folklore. However, I want to give some amazing examples with the evidence of 3D printing systems with specific layout that are successfully functioning today and that can be confidently indicated as the developments that make a significant contribution to the dynamic world of additive manufacturing. Why am I talking about classic 3d printing in the title of this article? The fact is that the last few decades have allowed the first additive technologies to gain ground and become a certain kind of classic standard for new production and new products, regardless of the 3d printing developing brand. Today, the world of AT has moved far ahead and can boast of new developments that have not grown popular yet due to the market persistence. Let us agree that in this article we will discuss industrial or professional production systems that differ for the better (except their price) from the desktop 3d printers in terms of reliability, high quality, versatility, accuracy, dimensions and performance.
Let me speak in a roundabout way, but not with the boring stories of the first occurrence of manual, and then digital technology of the layer-by-layer object synthesis. Any plant is interested in new managerial, digital, and production technologies for obtaining the cost-effective products with its rapid diffusion and without any significant transformation of routine operations. This often happens at the very beginning of their continuous improvement path, if that is the goal of plant management. In the future, such management can take a risk and be bent on global changes with the breakthrough solutions that will definitely make many plant departments nervous and actively involved in the production technology transformation. Thus, at the first stages, the management tries to help the lagging departments and processes using the patchwork (local) transformations. Believe me, 3D printing technologies are used when a lot of other methods have already been applied with no expected results. Boom! Finally, let’s turn to AT.
The long-term and rigorous market research allows the plant management to draw disappointing conclusions: at present, it is impossible to completely replace the conventional commercial technologies with the additive ones, but you can take risks for pilot production and development of new product options. Thus, the management has taken a risk, ordered, set up, and tested. Then, the following narrative is used to justify the costs: bionic design – light weight – customization – compaction – aggregation… Possibly, during the entire production cycle of a unit / product (the shorter it is, the more pronounced the effect) the happy owner will receive a 1–10% cost / time reduction (depending on the AM scope used). However, what’s done can’t be undone.
A team of designers and engineers begins to transform the classic design and manufacturing skills and increasingly incorporates new engineering thought into their work that is embodied by the innovations of the 3D printing world. The stepwise progressive movement with innovations leads to the possible AM abandonment by the plant, since the AM was one way or another integrated in the design documentation and technical processes. At this very moment we can talk about the AM diffusion that has become an integral part of the modern industrial production. The heads of departments report on the success of topological structure optimization, unprecedented local economic effects, space-saving production of parts on the small sites without the use of tooling equipment. It seems that everything looks optimistic, some people even find ways to invest for the production scaling. However, everyone expects something different from the AM.
Increased performance
for full-scale production
The main AM goal is to significantly increase performance for full-scale production. For the highly developed countries, AM is nothing more than just business. Even the most advanced 3D printer with one owner rarely has the service life of more than 3–5 years. During this period of time, it manages to become functionally (rarely physically) obsolete and does not reflect the current AM opportunities. Therefore, in order to stay on track and be popular in the market, the industrialist has to get rid of old systems and acquire new ones.
In Russia, things are somewhat different. It is no secret that due to the customs duties, logistics, and taxes, the cost of foreign equipment and imported materials may differ by 1.5–2 times from the purchase price. Therefore, the pay-back period will be noticeably longer than in the global practice. It is extremely difficult to find such high investments, despite the high quality of products, but in the absence of a noticeable payback period of 3–5 years, since the business laws and regulations are applied in this situation. It is necessary to honestly recognize that in Russia the level of innovative developments, requiring the fastest and simplest production of critical components without tedious preparation is not high enough, and this fact affects the use of additive equipment. Therefore, the renewability of the fleet of expensive foreign-made systems in Russia is not the highest in the world. In other words, the Russian plants use the obsolete equipment for a long period of time, and this equipment is less accurate, convenient, and efficient.
But what about the Russian developers? Are they not capable of producing the systems that copy the capabilities of successful foreign manufacturers, with due regard to the obvious absence of customs duties and comprehensive logistics, the use of inexpensive Russian components? Will this make it possible to influence cheapening of the manufactured systems, and as a result, to increase the final product attractiveness due to the decreased cost of active fixed assets? You will be right: perhaps they are capable. However, let’s ask ourselves the question relating to the real-world market innovativeness: is it available in the Russian developments? The most important question is whether the Russian 3D printers demonstrate a multiple performance improvement due to the proprietary developments? Try to answer these questions independently.
Finally, since we have begun to talk about automation of the future full-scale additive manufacturing, it is worth paying attention to the cyber-physical and modular layout solutions, as the most promising in this sense (Fig. 1) [1].
About workbenches and platforms
For many people, the perception of professional and industrial 3D printers and printing of plastic, ceramic, sand and metal products is usually based on the image of a cartesian reference system with three linear axes, X, Y, Z, and the relevant square or rectangular workbenches. In this case, we are usually talking about 3d printing with 2.5d axes, namely the full-fledged mechanical work of the head along the X and Y axes. The table usually moves along the vertical Z axis to a predetermined layer height that is often uniform throughout the entire printing cycle. This is the simplest implementation of the 3d printing principle (Fig. 2–3) [2, 3].
However, there is another, less common principle, according to which the work table, and not the head, moves along the Y axis, or even along two XY / XZ axes, and the head moves along the remaining axis, for example, the Z axis (note: the Russian “desktop” additive manufacturers often use the disparaging term “twitch-table” to indicate this principle in their everyday life).
Let’s not keep away from the LB-PBF / SLM, PBF / SLS, EB-PBF laser and electron beam technologies (Fig. 4), according to which the laser or electron beam, after appropriate preparation, is projected onto the working surface of the table with the material, that is, it performs all movements along the X and Y axes.
The table also moves discretely along the Z axis, by a value equal to the layer height. A more comprehensive layout already implies the addition of one or three rotary axes that rotate around the linear axes. Such a layout is typical for the systems applying the classic portal or console CNC equipment.
It is fair to note the usage of round rotary tables (turntables) in the technologies, such as:
metal DED-P (Fig. 5), DED-W (Fig. 5–6) (consoles, portals, robotic systems (RS)). Please note that the removable construction platform may have various shapes of geometric figures, subject to the allowable deviations of the flat surface shapes;
metal LB-PBF (Fig. 4) and plastic SLS with round building chambers (usually these are more affordable solutions that do not offer the tables with large dimensions);
plastic and composite FDM / CFC (RS) (Fig.5).
Such tables (except of round building chambers for LB-PBF) minimize wear and vibration of all components of the equipment that positively affects the system reliability and quality of the resulting products.
However, all these round tables are most often used only for cheapening and ease of use of several axes in the small-scale machine. What about the polar coordinate system in which each point in the plane is determined by two numbers, namely the polar angle and the polar vector? The DED-P, DED-W, FDM / CFC technologies can use it, although the polar system is not very convenient for an engineer. Will it stop a scientist or a developer who is eager to elaborate ideas?
Well, it seems that now we are ready to talk about the most important thing.
Forerunners of the future additive manufacturing
Thus, performance improvement to the level of conventional technologies is a barely achievable, but worthwhile goal for any AT. How can this be achieved over the course of several decades? You probably won’t find any useful formula. However, no one bothers us to imagine the future AM, or at least one of its important components, namely the type of workbench and specifics of its operation.
To better understand the trends, let’s start with the milestone developments in chronological order. We will not put a lot of time into a complete description of the technical process, we will give it as a homework to the inquisitive reader.
Evolve Additive Solutions with its STEP (Selective Thermoplastic Electrophotographic Process) technology (Fig. 7) became well-known in 2017 [5]. At present, AM is closer than ever to conquering a significant part of the traditional production market. However, this should happen only with an increase in the production rate by tens, and preferably hundreds of times. The development of Evolve Additive Solutions brings us closer to this moment.
However, in this case, the table moves linearly along the X axis back and forth and is synchronized with the rotation of multiple reels. The reels, in turn, perform multiple functions, including the neat transfer of each layer of the future part from the film to the workbench surface. When describing the STEP technology, I always give the example of traditional printing process, according to which the printing machines delivers the image to a rolled base material by impression using a stencil, a mould and electrophotography.
Almost the same principle is applied in this case, but the place of stencil is filled by the build and auxiliary material. The final product made of technical amorphous or semi-crystalline thermoplastic is isotropic along all three axes with the possible full-color printing and multi-material printing. The cost per part and the surface quality are comparable to the traditional production results. It’s very breathtaking, isn’t it? Such systems are very difficult-to-copy (reverse-engineering) and can only be used on an industrial scale. This is almost exactly what we need: extremely fast and relatively small-footprint solution with the ability to print really massive parts, given the large table dimensions. It is significant that this technology can be protected by a number of uncommon patents.
Tritone Technologies was founded in 2017 [7]. Its heart is the unique MoldJet hybrid technology that combines 3D printing technology described by an umbrella term of MJM (Multi Jet Modeling), MBJ / BJT (Metal Binder Jetting / Binder Jetting Technology) (Fig. 8), and traditional MIM / CIM (Metal / Ceramic Injection Molding).
This technological solution allows to make a layer-by-layer casting mold from the support material using a piezoelectric jet head and immediately fill its cavities with a build material made of a metallopolymer (MIM) or ceramic-polymer (CIM) composition. There is no only one such innovation in the invention of Israeli developers. The entire process takes place on a carousel (Fig. 9), consisting of 4–6 platforms that are alternately moved under the process device (printing, primary heat treatment, control). The declared efficiency is 220 cm³ – 1600 cm³ for the Dim and Dominant systems, respectively [8, 9]. In this case we see rotation as a logical method of compaction, acceleration and automation of full-scale production. It is unfortunate that the process is not truly continuous, as in the case with photopolymer resins (we will talk about it a little bit later), but is inherently discrete.
In 2021, Stratasys, Inc. presents several surprises at once in the form of an amazing concept of rotary J5 DentaJet, J5 MediJet, J35 Pro, J55 Prime 3D printers (Fig. 10) with a polar coordinate system [11]. The presented printers are good at everything: stunning design from the BMW designers, inherited from the F123 family FDM; high capacity; multi-materiality; reliability; portability. In general, it has all properties that are expected by the most demanding consumer from the office color 3D printing. One would think that this is the dream concept of the future printer! However, the limitations are the low performance parameters of the resulting products made of photopolymers, as well as an insufficiently high level of automation.
Forgive me, dear reader, but the last “fruit” for our still life does not correspond to the previously accepted chronological sequence of my story. It has been done intentionally to make meaning perfectly plain at the end of this review. The German company dp Polar GmbH [2] uses the rotational printing technology in polar coordinates titles “High-Speed Rotative AM (HSR)” using the piezoelectric ink-jet print heads Xaar 1003 by Xaar [12]. Of course, such heads are designed for the MJM inkjet photopolymer deposition (a similar technology is used by 3D Systems, Inc. – MultiJet Printing [13] and by Stratasys, Inc. – PolyJet [14]).
Since 2019, dp Polar has purported to be a company aimed to conquer the industrial customized manufacturing using the AT. The declared rate is about 10 l / h with a potential future build volume of 700 l per cycle. Automation is implemented in a very elegant way. One of the eight sections of the rotary table at any time can be replaced manually or by RS with a completely empty one, or with a section specially prepared for printing any functional layer or element (Fig. 11–12). Further, the section can be transferred to the next process stage, for example, for the support material dissolution.
dp Polar GmbH is already talking about the possible usage of its AMpolar systems for multi-material printing, including 3D printing of AME (Additive Manufactured Electronics) electronic components (Fig. 13) on any surfaces and multilayer structures with the conductive inks and dielectrics, including any wearable electronics (Fig. 14). In my opinion, this concept may lie at the root of the future printer development.
Conclusions
At present, we are witnessing not the prototypes and demonstrators, but the worthy commercial 3D printers, the forerunners of the future AM, combining the multi-material and multi-component printing (plastics, electronics, metals, ceramics) in one process cycle, for example, using the piezoelectric heads. Moreover, automation is logically and successfully implemented or will be implemented using the robotic systems. Such unmanned production may well take its place in the digital “plants of the future”, while relieving a person from routine work.
Will the system developers for full-scale additive manufacturing take advantage of such solutions? How will they solve the automation issues? Perhaps we are left with two options: to obediently wait for the answers to our questions or to join the ranks of developers, from the very beginning zeroing in on the comprehensive automation solutions for additive manufacturing.
AUTHOR
Dmitriy Trubashevskiy, Sales Director, Modern Equipment LLC, Moscow, Russia
ORCID: 0000-0002-0295-9835
or Forget Everything You Knew About Classic 3D Printing
D. S. Trubashevskiy
Modern Equipment LLC, Moscow, Russia
The main goal of additive manufacturing (AM) is to significantly increase the full-scale production capacity. The dynamic development of additive technologies (AT) is related to the prospects for its automation when integrating into the machine designs of the modular layout arrangements. The layouts are considered where the workbench is an important element for production automation and performance improvement of the entire process system. The usage of a round table with polar coordinates can affect the AM capacity. Various ATs are considered, including MJM, STEP, MoldJet, HSR, in order to demonstrate application of such workbenches.
Keywords: additive manufacturing, additive technologies, 3d printing, 3d printers, automation, robotic process automation, full-scale production, cartesian reference system, polar coordinate system, multi-materiality, piezoelectric heads, rotational 3d printing, 3d printing of electronic components, wearable electronics
Received on: 05,07.2022
Accepted on: 04.08.2022
INTRODUCTION
Like many wonderful legends without any facts and evidence, at present a phrase “Eppur si muove! Albeit it does move!” erroneously attributed to Galileo Galilei has firmly taken root in the folklore. However, I want to give some amazing examples with the evidence of 3D printing systems with specific layout that are successfully functioning today and that can be confidently indicated as the developments that make a significant contribution to the dynamic world of additive manufacturing. Why am I talking about classic 3d printing in the title of this article? The fact is that the last few decades have allowed the first additive technologies to gain ground and become a certain kind of classic standard for new production and new products, regardless of the 3d printing developing brand. Today, the world of AT has moved far ahead and can boast of new developments that have not grown popular yet due to the market persistence. Let us agree that in this article we will discuss industrial or professional production systems that differ for the better (except their price) from the desktop 3d printers in terms of reliability, high quality, versatility, accuracy, dimensions and performance.
Let me speak in a roundabout way, but not with the boring stories of the first occurrence of manual, and then digital technology of the layer-by-layer object synthesis. Any plant is interested in new managerial, digital, and production technologies for obtaining the cost-effective products with its rapid diffusion and without any significant transformation of routine operations. This often happens at the very beginning of their continuous improvement path, if that is the goal of plant management. In the future, such management can take a risk and be bent on global changes with the breakthrough solutions that will definitely make many plant departments nervous and actively involved in the production technology transformation. Thus, at the first stages, the management tries to help the lagging departments and processes using the patchwork (local) transformations. Believe me, 3D printing technologies are used when a lot of other methods have already been applied with no expected results. Boom! Finally, let’s turn to AT.
The long-term and rigorous market research allows the plant management to draw disappointing conclusions: at present, it is impossible to completely replace the conventional commercial technologies with the additive ones, but you can take risks for pilot production and development of new product options. Thus, the management has taken a risk, ordered, set up, and tested. Then, the following narrative is used to justify the costs: bionic design – light weight – customization – compaction – aggregation… Possibly, during the entire production cycle of a unit / product (the shorter it is, the more pronounced the effect) the happy owner will receive a 1–10% cost / time reduction (depending on the AM scope used). However, what’s done can’t be undone.
A team of designers and engineers begins to transform the classic design and manufacturing skills and increasingly incorporates new engineering thought into their work that is embodied by the innovations of the 3D printing world. The stepwise progressive movement with innovations leads to the possible AM abandonment by the plant, since the AM was one way or another integrated in the design documentation and technical processes. At this very moment we can talk about the AM diffusion that has become an integral part of the modern industrial production. The heads of departments report on the success of topological structure optimization, unprecedented local economic effects, space-saving production of parts on the small sites without the use of tooling equipment. It seems that everything looks optimistic, some people even find ways to invest for the production scaling. However, everyone expects something different from the AM.
Increased performance
for full-scale production
The main AM goal is to significantly increase performance for full-scale production. For the highly developed countries, AM is nothing more than just business. Even the most advanced 3D printer with one owner rarely has the service life of more than 3–5 years. During this period of time, it manages to become functionally (rarely physically) obsolete and does not reflect the current AM opportunities. Therefore, in order to stay on track and be popular in the market, the industrialist has to get rid of old systems and acquire new ones.
In Russia, things are somewhat different. It is no secret that due to the customs duties, logistics, and taxes, the cost of foreign equipment and imported materials may differ by 1.5–2 times from the purchase price. Therefore, the pay-back period will be noticeably longer than in the global practice. It is extremely difficult to find such high investments, despite the high quality of products, but in the absence of a noticeable payback period of 3–5 years, since the business laws and regulations are applied in this situation. It is necessary to honestly recognize that in Russia the level of innovative developments, requiring the fastest and simplest production of critical components without tedious preparation is not high enough, and this fact affects the use of additive equipment. Therefore, the renewability of the fleet of expensive foreign-made systems in Russia is not the highest in the world. In other words, the Russian plants use the obsolete equipment for a long period of time, and this equipment is less accurate, convenient, and efficient.
But what about the Russian developers? Are they not capable of producing the systems that copy the capabilities of successful foreign manufacturers, with due regard to the obvious absence of customs duties and comprehensive logistics, the use of inexpensive Russian components? Will this make it possible to influence cheapening of the manufactured systems, and as a result, to increase the final product attractiveness due to the decreased cost of active fixed assets? You will be right: perhaps they are capable. However, let’s ask ourselves the question relating to the real-world market innovativeness: is it available in the Russian developments? The most important question is whether the Russian 3D printers demonstrate a multiple performance improvement due to the proprietary developments? Try to answer these questions independently.
Finally, since we have begun to talk about automation of the future full-scale additive manufacturing, it is worth paying attention to the cyber-physical and modular layout solutions, as the most promising in this sense (Fig. 1) [1].
About workbenches and platforms
For many people, the perception of professional and industrial 3D printers and printing of plastic, ceramic, sand and metal products is usually based on the image of a cartesian reference system with three linear axes, X, Y, Z, and the relevant square or rectangular workbenches. In this case, we are usually talking about 3d printing with 2.5d axes, namely the full-fledged mechanical work of the head along the X and Y axes. The table usually moves along the vertical Z axis to a predetermined layer height that is often uniform throughout the entire printing cycle. This is the simplest implementation of the 3d printing principle (Fig. 2–3) [2, 3].
However, there is another, less common principle, according to which the work table, and not the head, moves along the Y axis, or even along two XY / XZ axes, and the head moves along the remaining axis, for example, the Z axis (note: the Russian “desktop” additive manufacturers often use the disparaging term “twitch-table” to indicate this principle in their everyday life).
Let’s not keep away from the LB-PBF / SLM, PBF / SLS, EB-PBF laser and electron beam technologies (Fig. 4), according to which the laser or electron beam, after appropriate preparation, is projected onto the working surface of the table with the material, that is, it performs all movements along the X and Y axes.
The table also moves discretely along the Z axis, by a value equal to the layer height. A more comprehensive layout already implies the addition of one or three rotary axes that rotate around the linear axes. Such a layout is typical for the systems applying the classic portal or console CNC equipment.
It is fair to note the usage of round rotary tables (turntables) in the technologies, such as:
metal DED-P (Fig. 5), DED-W (Fig. 5–6) (consoles, portals, robotic systems (RS)). Please note that the removable construction platform may have various shapes of geometric figures, subject to the allowable deviations of the flat surface shapes;
metal LB-PBF (Fig. 4) and plastic SLS with round building chambers (usually these are more affordable solutions that do not offer the tables with large dimensions);
plastic and composite FDM / CFC (RS) (Fig.5).
Such tables (except of round building chambers for LB-PBF) minimize wear and vibration of all components of the equipment that positively affects the system reliability and quality of the resulting products.
However, all these round tables are most often used only for cheapening and ease of use of several axes in the small-scale machine. What about the polar coordinate system in which each point in the plane is determined by two numbers, namely the polar angle and the polar vector? The DED-P, DED-W, FDM / CFC technologies can use it, although the polar system is not very convenient for an engineer. Will it stop a scientist or a developer who is eager to elaborate ideas?
Well, it seems that now we are ready to talk about the most important thing.
Forerunners of the future additive manufacturing
Thus, performance improvement to the level of conventional technologies is a barely achievable, but worthwhile goal for any AT. How can this be achieved over the course of several decades? You probably won’t find any useful formula. However, no one bothers us to imagine the future AM, or at least one of its important components, namely the type of workbench and specifics of its operation.
To better understand the trends, let’s start with the milestone developments in chronological order. We will not put a lot of time into a complete description of the technical process, we will give it as a homework to the inquisitive reader.
Evolve Additive Solutions with its STEP (Selective Thermoplastic Electrophotographic Process) technology (Fig. 7) became well-known in 2017 [5]. At present, AM is closer than ever to conquering a significant part of the traditional production market. However, this should happen only with an increase in the production rate by tens, and preferably hundreds of times. The development of Evolve Additive Solutions brings us closer to this moment.
However, in this case, the table moves linearly along the X axis back and forth and is synchronized with the rotation of multiple reels. The reels, in turn, perform multiple functions, including the neat transfer of each layer of the future part from the film to the workbench surface. When describing the STEP technology, I always give the example of traditional printing process, according to which the printing machines delivers the image to a rolled base material by impression using a stencil, a mould and electrophotography.
Almost the same principle is applied in this case, but the place of stencil is filled by the build and auxiliary material. The final product made of technical amorphous or semi-crystalline thermoplastic is isotropic along all three axes with the possible full-color printing and multi-material printing. The cost per part and the surface quality are comparable to the traditional production results. It’s very breathtaking, isn’t it? Such systems are very difficult-to-copy (reverse-engineering) and can only be used on an industrial scale. This is almost exactly what we need: extremely fast and relatively small-footprint solution with the ability to print really massive parts, given the large table dimensions. It is significant that this technology can be protected by a number of uncommon patents.
Tritone Technologies was founded in 2017 [7]. Its heart is the unique MoldJet hybrid technology that combines 3D printing technology described by an umbrella term of MJM (Multi Jet Modeling), MBJ / BJT (Metal Binder Jetting / Binder Jetting Technology) (Fig. 8), and traditional MIM / CIM (Metal / Ceramic Injection Molding).
This technological solution allows to make a layer-by-layer casting mold from the support material using a piezoelectric jet head and immediately fill its cavities with a build material made of a metallopolymer (MIM) or ceramic-polymer (CIM) composition. There is no only one such innovation in the invention of Israeli developers. The entire process takes place on a carousel (Fig. 9), consisting of 4–6 platforms that are alternately moved under the process device (printing, primary heat treatment, control). The declared efficiency is 220 cm³ – 1600 cm³ for the Dim and Dominant systems, respectively [8, 9]. In this case we see rotation as a logical method of compaction, acceleration and automation of full-scale production. It is unfortunate that the process is not truly continuous, as in the case with photopolymer resins (we will talk about it a little bit later), but is inherently discrete.
In 2021, Stratasys, Inc. presents several surprises at once in the form of an amazing concept of rotary J5 DentaJet, J5 MediJet, J35 Pro, J55 Prime 3D printers (Fig. 10) with a polar coordinate system [11]. The presented printers are good at everything: stunning design from the BMW designers, inherited from the F123 family FDM; high capacity; multi-materiality; reliability; portability. In general, it has all properties that are expected by the most demanding consumer from the office color 3D printing. One would think that this is the dream concept of the future printer! However, the limitations are the low performance parameters of the resulting products made of photopolymers, as well as an insufficiently high level of automation.
Forgive me, dear reader, but the last “fruit” for our still life does not correspond to the previously accepted chronological sequence of my story. It has been done intentionally to make meaning perfectly plain at the end of this review. The German company dp Polar GmbH [2] uses the rotational printing technology in polar coordinates titles “High-Speed Rotative AM (HSR)” using the piezoelectric ink-jet print heads Xaar 1003 by Xaar [12]. Of course, such heads are designed for the MJM inkjet photopolymer deposition (a similar technology is used by 3D Systems, Inc. – MultiJet Printing [13] and by Stratasys, Inc. – PolyJet [14]).
Since 2019, dp Polar has purported to be a company aimed to conquer the industrial customized manufacturing using the AT. The declared rate is about 10 l / h with a potential future build volume of 700 l per cycle. Automation is implemented in a very elegant way. One of the eight sections of the rotary table at any time can be replaced manually or by RS with a completely empty one, or with a section specially prepared for printing any functional layer or element (Fig. 11–12). Further, the section can be transferred to the next process stage, for example, for the support material dissolution.
dp Polar GmbH is already talking about the possible usage of its AMpolar systems for multi-material printing, including 3D printing of AME (Additive Manufactured Electronics) electronic components (Fig. 13) on any surfaces and multilayer structures with the conductive inks and dielectrics, including any wearable electronics (Fig. 14). In my opinion, this concept may lie at the root of the future printer development.
Conclusions
At present, we are witnessing not the prototypes and demonstrators, but the worthy commercial 3D printers, the forerunners of the future AM, combining the multi-material and multi-component printing (plastics, electronics, metals, ceramics) in one process cycle, for example, using the piezoelectric heads. Moreover, automation is logically and successfully implemented or will be implemented using the robotic systems. Such unmanned production may well take its place in the digital “plants of the future”, while relieving a person from routine work.
Will the system developers for full-scale additive manufacturing take advantage of such solutions? How will they solve the automation issues? Perhaps we are left with two options: to obediently wait for the answers to our questions or to join the ranks of developers, from the very beginning zeroing in on the comprehensive automation solutions for additive manufacturing.
AUTHOR
Dmitriy Trubashevskiy, Sales Director, Modern Equipment LLC, Moscow, Russia
ORCID: 0000-0002-0295-9835
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