Paulo Núñez

Paulo Núñez

Friday, 04 September 2020 23:18

3D Printing Glass

Additive manufacturing is the base of 3D printing, it has several methods but the most used and common are SLA (Stereolithography) or SLS (selective laser sintering) and FDM (fused deposition modeling). Both generally use polymers as the main material to produce prints and here is where things can get complicated, in this article we will cover the use of glass and its raw materials used to produce 3D prints.octype html>


Back in 2015, MIT researchers developed a 3D printer that melts glass to later extrude it to a desired form (mit.edu)


3D printing glass is not an easy task, there have been a few organizations and scientists that were able to produce a 3D printed glass piece. Most of these methods rely on high temperature to help reach the glass melting point to later mold it into the desired form, glass will require temperatures around a 1000 ºC to reach its fusion point.


MIT 3D printed glass pieces are beautiful and of complex shapes. (mit.edu)


A team of engineers from the University of Washington succeeded by using glass powder and a binder solution to make particles react and thus being able to lay them and form a desired glass object. The technique allows a new type of material (glass) to be used in a typical powder based 3D printing system.


This 3D printing method was named Vitraglyphic process and was created in 2009 (washington.edu)


In 2017, a German group of researchers from KIT (Karlsruhe Institute of Technology) used an SLA process to create intricate glass objects. In SLA printing, light is used to selectively harden liquid materials into solid parts, layer by layer. The team applied the SLA process to a special ink containing glass nanopowder suspended in a photocurable polymer, and then they fired the piece at 1,300 ºC to burn off the polymer and densify the glass.




Complicated high-precision structures made of glass can be manufactured with this method (kit.edu)


Most recently (November 2019), ETH Zürich have used a similar method as the KIT researchers, they have developed a special resin that contains a plastic and organic molecules to which glass precursors are bonded, the resin can be cured by UV Light using commercially available DLP 3D printers.


Complex objects can be made from different types of glass, or even combined in the same object using the technique (ethz.ch)


After the resin is cured into the desired form, the piece is subjected to two different temperatures: at 600˚C to burn off the polymer framework and then at around 1000˚C to densify the ceramic structure into glass. During the firing process, the objects shrink significantly, but become transparent and hard like window glass.

The revolutionary AMpolar i2 brings several features and advantages to printing Additive Manufacturing parts on a truly industrial scale.

First introduced in Formnext 2019, the AMpolar i2’s patented Additive Manufacturing process uses an array of Xaar 1003 printheads to jet parts at volume, and at a significantly reduced cost when compared to traditional 3D printing machines.

The highly productive single-pass printing process delivers build volumes of up to 700 liters across its pioneering, continuously rotating print platform.


dppolar

The printer employs the manufacturer’s proprietary technology, called High-Speed Rotative AM Process (HSR), which as its name suggests uses a one of a kind, constantly rotating print platform to create several parts at a time. (dppolar.de)


In terms of capabilities, the printer has a multi-process ability where additional automated equipment can be integrated within the printing process.


dppolar

For example, it is possible to combine the rotating print platform with a fully automated pick-and-place process that will pick up parts and place it in a position as printing is resumed to complete the fixture. (dppolar.de)


The 3D printer has two different modes of production, the Manufacturing Mode and the Prototyping Mode. In the MM mode, the user will benefit from the platform’s large build volume for series production. On the other hand, in the PM mode, the focus will be to enable high speed rapid prototyping due to shorter cycle-time.


dppolar

In fact, the AMpolar i2 is equipped with three individual print stations, allowing the production of multi-material parts very quickly. (dppolar.de)


The German company dp polar has partnered with ALTANA AG, a leading specialty chemicals company, to offer tailored materials for its platform.


dppolar

Cubik Ink is their material suite, with each material available in transparent and various colors. (dppolar.de)



dppolar

Another feature on the AMpolar i2 are the water soluble support materials that allows quick and automatic removal of all support structures. There is no need for additional chemicals or mechanical treatments. (dppolar.de)


As we covered in previous articles, the Xaar 1003 printhead combines highly accurate drop placement, consistent drop volume and high frequency jetting with variable drop size capability to deliver precise functional fluid control. This is essential for precise production patterns and surface characteristics.

Mike Seal, Xaar’s Business Development Manager, Advanced Manufacturing and 3D Printheads said; “dp polar’s use of the Xaar 1003 printhead and the innovative design of the AMpolar i2, shows the natural progression of photopolymer jetting from a prototyping technology to a true manufacturing process; a transition we are seeing more and more within functional inkjet applications”.


dppolar

the Xaar 1003 printhead family is a versatile line with several use cases, including 3D printing (Xaar.com).


Friday, 10 July 2020 18:24

Color changing Inks

There are several mechanisms in which color changing of an ink can occur, in this article we cover specifically two, photochromic and thermochromic. The first meaning that a specific light type (wavelength) triggers the ink and changes its color, thermochromic means that color change will occur depending on the temperature it has been designed to activate.


Color-changing-Inks

Photochromic T-shirt on its passive state (left) and activated by UV Light (right) (colourchange.com)


Photochromic inks are invisible under artificial light and will appear visible once exposed to outdoor sunlight or UV / black light. These inks can be applied to papers and boards or to textiles. This type of inks and dyes change their molecular structure from a clear or white color and darken revealing its true color (on exposure to specific types of light of enough intensity, most commonly ultraviolet (UV) light sources, (UV light in the range of 300 to 360 nanometers).


Color-changing-Inks

Photochromic pigment of different colors activated by a concentrated UV-light source (nanomatrixsecure.com)


Photochromic dyes are reversible, when placed into sunlight or a UV-Light source they become activated, in an “excited” state, and depending on the manufacturer it takes from 10 to 20 seconds to allow the photochromic compound to turn into a darker color. In the absence of activating light when the UV light source fades, the effect is reversed and they return to their clear state after 5 minutes or less.


Color-changing-Inks

Photochromics are great on white t-shirts but not limited to be used on it (sfxc.co.uk)


Thermochromic ink or fabrics change color in response to temperature fluctuations, meaning heat will enable it to change color at its designated temperature, color change activation occur at temperatures from -10°C up to +70°C, they usually are reversible, changing either way as the ink warms or cools. There are two primary types of thermochromic coatings: liquid crystals and leuco dyes.


Color-changing-Inks

Thermochromic fabric, color change is activated by body temperature.


Liquid crystals dyes rely on liquid crystals contained in tiny capsules. The liquid crystals are cholesteric, this refers to the arrangement of molecules, which means that its molecules arrange themselves in a very specific helical structure. These structures reflect certain wavelengths of light. As the liquid crystals heat up, the orientation of the helices changes, which causes the helices to reflect a different wavelength of light. To our eyes, the result is a change in color. As the crystals cool down, they reorient themselves into their initial arrangements and the original color returns.

Leuco dye inks, are a darker color when cooler than their temperature activation point, and lighter in color or virtually clear when warmer than their activation point, temperature uses of these inks generally fall into three areas: cold, body temp and hot.


Color-changing-Inks

A black thermochromic ink (with body temp activation) screen printed over and obscuring a litho printed image or words, can become clear and reveal the litho image when it is touched or rubbed. (sfxc.co.uk)


A black thermochromic ink with a higher activation temperature can be screen printed onto a coffee coaster, so that the thermochromic ink becomes clear when heated by a hot mug, revealing the message or branding also printed on the coaster.


Color-changing-Inks

Heat-sensitive vans shoes will change color temporarily when exposed to body heat and return to original color at room temperature (vans.com)


Friday, 19 June 2020 20:36

UV-Degradation in Plastics

Some plastics can be susceptible to damage when they come into contact with Ultraviolet (UV) rays for a prolonged time, leading to cracks or color fading and even the disintegration of the plastic. This raises the question; Which plastics are UV stable or can withstand UV exposure better?

Ultraviolet radiation consists of photons with high energy relative to visible light, this radiation is split into three types, these are UV-A, UV-B and UV-C.

UV-A has a wavelength range of 400-320 nm, while UV-B has a range of 320-280 nm. Meanwhile, UV-C’s range stands at around 280-200 nm.

UV-C is not present in our perceived sunlight, because wavelengths lower than 300 nm are absorbed by the ozone layer in the upper atmosphere, the general effect of UV-C is killing bacteria and microorganisms by disrupting their DNA, so we can focus on UV-A and UV-B.

UV effects on different types of plastics

UV energy can excite photons, when absorbed by plastics, in turn, can create free radicals. This is the beginning of degradation. As a matter of fact, several pure plastics simply cannot absorb UV radiation.

The most common ways you can detect if a plastic is being affected BY UV are:

  • You may notice a pale appearance or color fading on the surface of the material
  • The plastic’s surface becomes brittle or cracked

  • UV-Degradation-in-Plastics

    Notable color fading in exposed to sunlight (UV radiation) Nylon rope. (quora.com)


    The most widespread UV damage mechanism in plastics is called chain scission by photolysis, this is the breaking of long chain polymers into shorter ones. This almost always results in a degradation of physical properties such as strength or degradation of visual properties such as color and texture.

    UV resistant plastics

    Some polymers are more stable to UV exposure than others, there is a class of high-performance polymers called fluoropolymers that exhibit excellent UV resistance. Teflon has become a genericized name for all fluoropolymers. fluoropolymers are exceptionally resistant to UV degradation. Accordingly, PTFE or FEP are almost always used for wire insulation on UV lamps or in UV equipment.

    Here is a short list of them:

  • Polyethylene
  • Polytetrafluoroethylene (PTFE)
  • Fluorinated ethylene-propylene (FEP)
  • Polyvinylidene fluoride (PVDF)

  • UV-Degradation-in-Plastics

    With their high performance against UV come high prices, fluoropolymers are among the most expensive polymers.


    UV coatings and other protection

    UV protective curable coatings are composed of acrylate functionalized resins, which polymerize or cure instantaneously upon exposure to UV light, thereby being easy to apply and efficient. Energy-curable resins can be 100% solids materials or can be diluted with solvents for ease of application, since coatings on plastic parts are mostly spray-applied, solvents are used to reduce viscosity.

    In terms of the components more likely to be at risk of UV damage, automotive parts are high on the list. The effects will predominantly result in a change of the material’s surface layer – and some plastics, if damaged by UV, will ultimately lead to the component failing altogether.

    The best coatings are multi-layer systems. The coating of plastics begin with the application of a primer, which has a binding effect on the basecoat, that is then applied over the primer. Finally, a clear-coat containing the light stabilizers for UV protection seals the coating system protecting the plastic.

    Source: UV solutions Mag

    Mimaki has just introduced their 3rd 3D printer, they first debuted the Mimaki 3DUJ-553 back in September 2017, a 10 million-color 3D printer; In contrast their new product, the Mimaki 3DGD-1800 is a large-sized/high-speed 3D printer, to be precise a machine that can print at a maximum speed of 35cm (height) per hour, this in a special UV curing resin.


    Mimaki 3DGD-1800, a large format 3D printer

    This massive 3D printer is capable of producing 1.8-meter height prints (Mimaki.com).


    The Mimaki 3DGD-1800 is a solution developed in association with Massivit 3D, the pioneer in large format 3D printers, the printer’s available molding area is 1.45 x 1.11 x 1.8 meters (57.1 x 43.7 x 70.9"), the printer has 2 gel dispensing extruders giving the machine the ability to print 2 different objects at the same time, basically the same specs the Massivit 1800.


    Mimaki 3DGD-1800, a large format 3D printer

    This massive 3D printer is capable of producing 1.8-meter height prints (Mimaki.com).


    Just like the Massivit 1800, the Mimaki 3DGD-1800 uses the Gel Dispensing Printing (GDP) technology developed by Massivit, this guarantees fast curing times and reduces the need for support material, this is done thanks to an ultraviolet photosensitive gel-type curable resin, the resin is laid out in a similar way as Fused Deposition Modeling (FDM) 3D printers do, with the difference being the material used.


    Mimaki 3DGD-1800, a large format 3D printer

    The UV-curing resin is laid by the extruder while some high power UV-LED’s let it cure almost instantly (Massivit3D.com).


    Mimaki first announced their latest 3D printer, the 3DGD-1800, back in march, and has made it available since April 1st 2020

    In the following table you can see the complete specs of the Mimaki 3Dgd-1800:

    3DGD-1800

    3D printing method

    Gel Dispensing Printing / Dual print

    Printhead

    2

    Nozzle size (dia.)

    1.8 / 2.6 mm (Replaceable)

    Max. printing size / Weight

    W1,450 × D1,110 × H1,800 mm / 150 kg

    Printing speed (*1)

    Height 350 mm/h

    Layer pitch

    Normal

    1.3 mm

    Quality

    1.0 mm

    High Resolution

    0.8 mm

    Printing material

    MG-100W (White UV curable resin)

    3D data format

    stl, obj, 3ds, ply, blend

    Slicer software

    3DGD Slicer

    Operating
    specifications

    Power

    3×25A、380-400VAC±10%、50/60Hz

    Air pressure

    600 to 800 kPA

    Power consumption

    10kW (Printing)

    Temperature

    16 to 30 degC.

    Interface

    Ethernet

    Dimensions (W x D x H)

    3,000 × 2,200 × 2,800 mm

    Weight

    2,500 kg


    Source: Mimaki


    Monday, 18 May 2020 23:54

    Printshop Workflow Automation

    Every print shop faces some common challenges when it comes to managing their workflow, process automation is usually found in large print shops, with large print volumes and where jobs are printed over and over again.


    Printshop-workflow-automation

    Workflow Automation Software works in combination with other programs running in your print shop, it is important to note that some of your actual software infrastructure may already have some automation processes involved. To further automate the workflow is important to be able to communicate one software with another, in most cases, specific Workflow Automation software may not be required.

    Software

    Generally, print shops have one or more of the following software running:

    • Web to Print Software
    • Variable Data Composition
    • MIS Print Management
    • Color Management

    A web to print software has many advantages and functionalities, first it gives your shop a front store, helping users find their way into what they will need and letting customize their final product, it helps the owner determine a print order management.

    Variable data printing enables the mass customization of documents with text and image changes for groups of addresses based upon which segment of the market is being addressed. Customization and personalization allows a company to connect to its customers using a variety of software solutions.

    MIS (Management Information Systems) help print shops collect and manage their own information for decision making, this software integrates with existing systems to help handle real time information and tasks, harvesting information and letting other connected applications take actions is essential for workflow automation.

    Color Management it is the measurement and control of each and every step in your production process, maintaining as a goal to know exactly what your output is going to look like, before you actually print.

    Sometimes, specific software may comply with many of the above-mentioned functions, for example:

    Agfa has developed a complete, automated Sign & Display production hub called Asanti, the software includes a color management solution, integration with the latest version of Adobe PDF Print Engine (APPE), highly specific functionalities (e.g. nesting, see-through concept, proofing support) and fast, automatic pre-flighting.


    Printshop-workflow-automation

    Asanti is sold as a scalable workflow tool that distributes input from various sources over multiple hardware systems. (agfa.com)


    Another good example is Durst Workflow software, claimed to be an All-In-One solution, which includes all steps of the pre-press and production process in one single application, modules are available for different processes such as: Label Workflow, Large Format Workflow and Corrugated Workflow.


    AT-Inks-UV-UV-LED-Inkjet-Ink

    Durst Print Workflow can also be integrated into an existing ERP/ MIS environment, and is said to be an all-in-one solution thanks to its Job management and reporting tools, color management and data and print preparation. (agfa.com)


    Workflow

    You need to determine the existing kind of production workflow currently being used in your print shop, if the work is built around a software-based flow of work, or from the point of quoting to the point of delivery, or do you have semi-automated processes linked by spreadsheets and/or different software, sticky notes, whiteboards, phone calls, regardless of any, if your workflow is not efficient, neither is your production process.

    Possible and existent current workflow inefficiencies could be:

    • Customer interactions and order entry.
    • Too many persons involved in same tasks, generating bottlenecks.
    • File checking and prepress preparation.
    • Print programming and physical printing.
    • Finishing, shipping and fulfillment.

    AT-Inks-UV-UV-LED-Inkjet-Ink

    Usually these workflow inefficiencies lead to bottlenecks, the mayor bottleneck in any print shop is preparing files to properly be printed, this process can be automated in most cases.


    There are several bottlenecks but the most common ones are listed below:

    • Dealing with a high number of small jobs
    • Increasing throughput; shortening production times
    • Keeping up with change; training users
    • Customizing the workflow to specific needs
    • Complexity of software

    Deciding to move to any new software for production workflow (MIS or similar) usually comes after evaluations of current productivity and researching for the right tool or correct operation processes. Reconsidering strategy often leads to new initiatives that include reexamining workflow initiatives.

    For smaller shops, costs control is a must, so automation and use of modern print and workflow management tools becomes an investment that can convert into a risk, due to the potential expenses involved in implementing it, but at the end, it is all the cost of success.

    Workflow initiatives and enhances

    • Add workflow to offer new products & services.
    • Improvement of process automation.
    • Integration of workflow components.
    • Improvement of customer interactions via web-based systems.
    • Improvement of operational efficiency (billing, invoicing, CSR).

    AT-Inks-UV-UV-LED-Inkjet-Ink

    Print shop workflow depends on your infrastructure, equipment and resources.


    The best practice is to adopt workflow method and solution that helps automate processes, while focusing on efficiency, decreasing the operational costs while still increasing throughput and depending less on human intervention, in order to have employees invest time in more productive tasks.

    Plastics and “green choice” usually don’t go together as most plastic materials are made from petroleum, these include: polyethylene, PVC, polypropylene, polystyrene, polyester, nylon and acrylic.


    plastics-in-the-ocean

    Most plastics don’t decompose. This means plastic can stick around indefinitely, destroying marine ecosystems. (noaa.gov)


    In the past decades, the search for an eco-friendly alternative to petroleum based plastics has led to the development of several bioplastics; materials specifically made from renewable resources and therefore diminishing the amount of energy required to produce them. Some are made from plants, most often from sugar cane or cornstarch, although they can also be produced from potatoes, or other plants, these plastics are often referred to as PLA (PolyLactic Acid or PolyLactide) or Cellulose Acetate.


    plastics-in-the-ocean

    To transform corn into plastic, corn kernels are immersed in sulfur dioxide and hot water, where their components break down into starch, protein, and fiber. The kernels are then ground and the corn oil is separated from the starch. (columbia.edu)


    Bioplastics are generally considered to be more eco-friendly than traditional plastics, this isn’t necessarily true, and bioplastics have a significantly lower carbon-footprint than traditional plastics over their lifetime. But in order to degrade bioplastics, most of them need high temperature industrial composting facilities to break down the material in less than 3 months, but it will take about 1,000 years to degrade in a landfill.


    Landfill-full-of-plastic-waste-Drowning-in-Waste-WOIMA-Corporation

    Landfills prevent waste from biodegrading, especially plastics. (thisisplastics.com)


    Very few cities have the infrastructure needed to degrade bioplastics and the problem magnifies when these plastics are not separated correctly from other plastic types such as PET (polyethylene terephthalate). The problem is when plastics get recycled, they are not compatible and the resulting plastic batch may get rejected as a consequence.


    plastics-recycling-centers

    Plastics need to be classified in order to be recycled correctly.


    The alternatives bioplastics are limited, PHA (polyhydroxyalkanoate) is one of them, a plastic made from living things. PHA is a unique polyester made naturally by certain bacteria, generally from organic waste. It is used to make plastic bags and single use containers; in the medical field is where this material shines, thanks to its biodegradability it can be used to make sutures, bone plates, orthopedic pins, etc.


    PHA-bioplastics

    Plastic bags and other articles made from PHA plastic. (wur.nl)


    PHA is biocompostable and marine degradable and has no toxic effects, but currently is difficult and expensive to produce.

    Source: University of Florida, Columbia University

    Columbia University
    https://blogs.ei.columbia.edu/2017/12/13/the-truth-about-bioplastics

    University of Florida
    https://sfyl.ifas.ufl.edu/media/sfylifasufledu/flagler/sea-grant/pdf-files/microplastics/Bioplastics-vs-petroleum-plastic-final.pdf

    Keep up with the latest trends about de digital printing industry and learn more about different technologies, equipment, media & substrates, inks, etc.

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