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Many products in recent years have benefited from see through plastic parts to improve interaction, show off internals, display lighting effects, or just to be stylishly unique. &nbsp;In some cases very little cost will be spared to achieve an optical clarity or just the right look, but in most products much less thought is put into what it will take to make the clear plastic elements capture the vision depicted in early development renderings. &nbsp;Some upfront discussions and planning with the product development team can help focus expectations, and needed steps to get the see through parts to meet their intended goals, at reasonable costs.If the clear parts in question are not intended to be a light shaping optic or clear window for an instrument, then there is actually some latitude in making them see through. &nbsp;This doesn&rsquo;t mean they will ever be as easy as opaque, textured plastic parts, as transparent plastic items have shinny finishes and show internal molding trace features like ejector marks that would be otherwise hidden. &nbsp;These will always present more of a challenge.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1587410844130-clear-plastic.jpg"><figure><figcaption>Different end customers will have different requirements for plastic part optical clarity.</figcaption></figure> First decide what is really expected of the clear parts in the intended design. &nbsp;If they are not an &ldquo;A&rdquo; surface feature (primary visible face of the product), or if the parts might have a light frosting on them to help defuse lighting or appearance, then some of the concerns on the part&rsquo;s clarity, look through properties, and molding aberrations may not be much more of a concern than other non-transparent parts. &nbsp;However, if the clear part in question is more front and center, the expectation of their visual perfection will need to be set higher. &nbsp;It will be important to consider early on what the clear part&rsquo;s function will be. &nbsp;Besides being transparent does the part perform other functions like mounting other internal components and holding housing pieces together? &nbsp;This will increase the number of internal features which will impact look through quality. &nbsp;Can the clear surface of the part in question be simplified, avoid internal features, or can the clear portion be a separate, simpler part? &nbsp;Lastly, is the style of the clear feature in the part really of value to the overall look of the product? &nbsp;Is it functional and an integrated part of the design which promotes the product, or is it just empty and costly feature?<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1587410869528-clear-headlight.png"><figure><figcaption>Clearly excessive? It did not seem to promote sales.</figcaption></figure>So you now have your clear parts confirmed and what is expected of them. &nbsp;As mentioned, there may still be room to simplify them without compromising the intended look of the product. &nbsp;Larger parts will be more challenging in some ways, molding large clear parts usually have features and ejector marks on the inside. &nbsp;Ejectors are parts of the tooling that push the part out of the mold and leave witness marks around their edges, usually little circles.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1587410945759-cis.jpg"><figure><figcaption>Large upper and middle doors molded of clear UL rated plastics needed strengthening and alignment features that would not occlude the view of the blades. Detailed attention in the beginning phases led to smoother transition from design and prototyping to production.</figcaption></figure>So can the clear surface be replaced with clear sheet material and still be integrated into the product design cleanly? &nbsp;The answer is usually yes if this is considered early on, and the benefit is usually avoiding many hassles getting a molded part intended for see through to make for a good quality clear part which can be delivered in production with reasonable costs and time to market. &nbsp;Going with injection molded clear panels can add significant cost to yield reasonable production quantities simply because they have so many opportunities for reject-able flaws and extra delays to get the molded parts dialed in during the pre-production process. &nbsp;On the other hand flat extruded clear sheet material, Acrylic or Polycarbonate, already has good, controlled clarity. If the design only requires the face to be flat or bend around a single axis, then integrating this sheet material into other framing parts can reduce risks by ensuring quality and time to market.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1587410997630-cis2.jpg"><figure><figcaption>Large framed clear sections lend themselves to utilizing clear material with lower risk in production ramp up and production rejects. Lower left mid-section conceals convoluted, molded clear light pipe.</figcaption></figure>However; not all designs lend themselves to flat or single bend direction clear parts, nor can the desired fit up always be achieved. In this case vacuum or pressure forming a clear sheet material can result in clear parts that allow for various surface forms with less risk of mold flow and forming imperfections. &nbsp;This is not risk free as heating and forming processes can produce optical variations in the newly re-shaped sheet, but these feature induced affects are usually where they would be expected to be, the process is less expensive to tool for than injection molding, and thermal forming inherently does not have mold flow variations which can exhibit imperfections.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1587411107029-clear-plastic-2.jpg"><figure><figcaption>Clear wind screen is thermo-formed, as it bends in two directions, and has airflow openings</figcaption></figure> <img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1587411117415-clear-plastic-3.jpg"><figure><figcaption>Early LED light bulb housing vacuum formed from heated, clear sheet shows consistent clarity</figcaption></figure> If you need to go with injection molding then the simple better approach is still preferred. &nbsp;And, just as thermal forming geometry variations can cause visibility issues, making injection molded clear parts with simpler geometry variations will help reduce dial in time of the new part and reduce rejects. &nbsp;Even if the mold flow and knit lines are working well, large or odd shaped thickness transitions in the part can cause easily seen sinks or odd light bending effects that will be noticed. &nbsp;This is not to say you can only mold sheet like pieces (even these will be more challenging than thermo-forming extruded sheet material), but is to say that thought needs to be put into the features and shape of the clear part to be molded. &nbsp;Walls and ribs will not be hidden as well, and even if the part is not intended to transmit light, these transition features will catch or amplify the light available, and highlight themselves. &nbsp;Returns walls, if near the edges of a clear part, like those of a water glass or head lamp housing, will also cause visual variations, but at the sides of the parts the junctions and variations are less noticed, and more acceptable if seen.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1587411159050-clear-plastic-4.jpg"><figure><figcaption>Top molded edge of lamp housing above round bulb causes light inflections but this is at a deliberate junction and not excessive</figcaption></figure>This is why heavy ribbing or screw bosses on the inside central regions of a clear part is a poor choice. &nbsp;Even if your design is ode to the see through Apple products of the past and looking into the guts of the device is part of the plan, keep in mind these inner features and transitions will many times have exaggerated visual impact due to lens like effects in junctions and rounds, and that Apple spent a great deal of time making all of those inside features just right so they appeared at the intended visual &ldquo;volume&rdquo;. &nbsp; If they had not, then the see through product affect would have appeared poorly executed, and don&rsquo;t forget how much more those see through computers sold for compared to the more plain, opaque PC competition. &nbsp;Some of the extra cost was due to the extra design burden.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1587411185928-8-1-1.png"><figure><figcaption>Top cover required notable effort by development team to achieve large clear zones.</figcaption></figure> With your molded clear part, extra attention will have to be paid to tool draft angles too. &nbsp;Draft is the tapper on the inside of the metal mold that allows the plastic part to be removed without having to drag all along the inside walls of the mold and be damaged during de-molding, think Jello molds. &nbsp;Although there may be a very polished finish on the injection mold tool, easing the release of the formed plastic part, the clear part will show scraping on the inside or outside surface much more readily. &nbsp;As well, any side actions or lifters in the tool, which are pieces of the tool that cam out of the way to form undercut hooks in the plastic part that would otherwise prevent removing the plastic part from the tool, any of these can leave marks on faces of the molded plastic part. &nbsp;For a plastic part that is clear then these witness lines and slightly mismatched sub-surfaces, as noted above, can be unavoidably visible, and even ugly. &nbsp;These features and tooling options need to be worked through with more attention to detail from conception of the parts in the beginning to thorough interactions with the mold tool design team closer to the end of the project.Lastly, if you are using the clear part for some kind of lighting effect or indication, like a custom light guide, plan on creating mock-ups and prototypes to truly test this out. &nbsp;Often even simple looking light pipe designs can be problematic to get the right look and even brightness, and larger diffused lighting usually requires many iterations. &nbsp;Make sure the electrical engineering team is included in discussions on this as well as the proper number of light sources, type and the ability to adjust the light sources&rsquo; output will be key to dialing in the desired effect. &nbsp;There is no point to spending tens of thousands of dollars to make a poor electrically designed light source for the product.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1587411224692-clear-5.jpg"><figure><figcaption>Convoluted light pipe evolved with 3D printed mock-up at top, machined prototype middle, and production unit at bottom. Client had already completed light source circuit board with no thought to visibility before design work began.</figcaption></figure> <img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1587411240885-clear-panamax.jpg"><figure><figcaption>Evenly lit molded surround rings use minimal light sources, developed with Panamax.</figcaption></figure> So don&rsquo;t be afraid to go clear. &nbsp;Just keep in mind that to execute the design efficiently and effectively there will need to be attention to details with the whole team from the beginning. &nbsp;Then you should be able to see your pathway to your final design clearly.

Looking from the inside on clear plastic parts.

How to Design See-Through Plastic Products

The fourth industrial revolution and the technologies that create it explained: The whole is bigger than its parts.

Industry 4.0 Deep Dive. Part 1: Introducing smart manufacturing

<a href="https://www.forbes.com/sites/michaelmandel1/2019/01/02/2019-the-year-of-the-manufacturing-platform/#145bca203688" rel="noopener noreferrer" target="_blank">Michael Mandel&rsquo;s Forbes article about manufacturing platforms</a> brings out many perks of having manufacturing on the cloud. He sees it as the next step in the manufacturing industry.How does it actually help the users and why is it considered the future of the manufacturing sector? Let&rsquo;s see.<h2>What Is Cloud Manufacturing?</h2>If the term &ldquo;cloud&rdquo; gives you a headache, let&rsquo;s try to define that.The definition of &ldquo;cloud computing&rdquo; is the practice of using a network of remote servers hosted on the Internet to store, manage, and process data, rather than a local server or a personal computer.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1585647597551-cloud-computing-2153286_640.png">Devices from anywhere have access to the infoThe same principles of shared information are at use with cloud manufacturing. It is a service-oriented business model to share manufacturing capabilities and resources on a cloud platform.In simple terms it means that people can visit a website to order their manufacturing, while the production is not limited to one company only. All the necessary info about manufacturers is available on the cloud.This creates a model where several companies are sharing their capabilities with those website visitors.At the same time, these platforms are not just mediation services. They offer possibilities to reduce environmental impacts and cut down costs by making intelligent decisions.Today, we see such manufacturing platforms offering services for sheet metal fabrication, 3D printing, <a href="https://fractory.com/what-is-cnc-machining/" target="_blank">CNC machining</a>, etc.<h2>The Objectives</h2>The main reason for the growing popularity and belief in cloud manufacturing is its sustainability.Whereas the demands for lower environmental impacts and costs are growing, many are seeking for solutions in the realm of on-demand manufacturing. And cloud manufacturing&rsquo;s aims align well with those needs:<ul><li>Enhanced efficiency</li><li><a href="https://fractory.com/cost-reduction-manufacturing/" rel="noopener noreferrer" target="_blank">Reduced production costs</a></li><li>Optimal resource allocation</li></ul><h2>Features and Benefits of Cloud Manufacturing</h2>How are these goals attained, though? For that, we shall take a closer look at the key characteristics of cloud manufacturing.FlexibilityDepending on the manufacturing platform, cloud manufacturing offers a large variety of capabilities at one place.The manufacturing of parts is assigned to the nearest manufacturer who has the expertise to execute the job. Thus, the supply chains are highly configurable and not fixed, minimising the reliance on certain connections and partnerships.Also, the automated system&rsquo;s capability of choosing a production partner based on those qualities accounts for achieving lower costs and lessened environmental impacts through shorter delivery distances.Production QualityQuality is one of the key aspects customers look for in manufacturing. Finding great suppliers is not always an easy task though.Some cloud manufacturing platforms just try to get as many partners on board as possible. Others do their due diligence and send in a bunch of test orders first.This helps to ensure great production quality without having to go through the pre-vetting process on your own.Shared AccountsThe access to procurement information is available for anyone involved. While legacy workflows include back-and-forth emailing, the information is not readily available for every related person to see.With manufacturing platforms, any involved party has an overview of progress. This lets a team of several members work on a project at once without the need for constantly keeping each other updated.Instant QuotesThe ability to receive instant quotes for CAD models or drawings enhances efficiency and offers optimal resource allocation. Less time is now spent on communication and engineers can direct their efforts towards value-adding activities.All the while these intelligent systems are accruing data to optimise the pricing process further.ManufacturabilityGiving out instant quotes needs a complicated system able to assess the uploaded files. This also means that the platform should not give out quotes to parts that are impossible to manufacture.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1585647766742-CAD-file-1.jpg"><figure><figcaption>Easy to make in CAD, impossible to manufacture by bending</figcaption></figure> Assessing manufacturability takes the geometric dimensions into consideration. A price is displayed only if the assessment is positive.At this stage of development, cloud manufacturing platforms still have some limitations. So the answer to the above-mentioned question may not always be final.Combining the answers with logical thinking, a client can use this assessment for redesigning the parts if necessary.Sharing the LoadCloud manufacturing helps to keep the lead times low by distributing work evenly.An example:A person orders 1000 parts. Manufacturer A has the capabilities to perform it but the production is full for the moment.The info about availability is on the cloud.Then we have manufacturers B and C who are also partners. Although neither of them has the capacity to perform the job on their own, the order will be divided between the two.This way the order can be sent to production without waiting for manufacturer A to finish his current job.Such work would be tedious manually but simple for an always-informed manufacturing platform.Service Oriented ManufacturingManufacturing is usually production oriented. This means that the companies providing the services are only focusing on one aspect of the process.Cloud manufacturing is looking to change that by offering resources and capabilities at the same place. Also, many manufacturing platforms take care of the delivery of the goods instead of leaving that to the customer.Such a step forward leads to a more compact and easier-to-manage solution.Volumes as LeverageCloud manufacturing platforms can accumulate large numbers of orders, making them valuable partners for production companies.Such volumes make a great leverage in bargaining cheaper prices.Manufacturing platforms often use pay-as-you-go model for profiting, adding an extra % to the final cost. Still, with their initial discounts, the final price for the customer is better than they could negotiate on their own. And this applies to cases where they could find a similarly-priced manufacturer in the first place.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1585647814031-Scrap-metal.jpg"><figure><figcaption>Someone has to pay for scrap metal</figcaption></figure> Often, small orders are also accumulated to make up a large one for better material usage. Less scrap is another way to achieve better prices.CapabilitiesExtensive partner networks ensure the possibility to produce a large variety of parts.Gathering a lot of manufacturers with different expertise and machinery under one name, the customer can get hold of the best equipment without much hassle.Cloud manufacturing platforms have the data about possibilities and limitations. Thus, they can direct jobs to relevant partners only.Less Points of FailureAs stated before, cloud manufacturing encompasses all steps from quoting to delivery. Therefore, there is only one point of contact.This means that the responsibility also lies with one company and dealing with reclamations, delays, etc. is that much easier.Short Go-To-Market TimesHaving the possibility to quote and send parts to production without first establishing connections in the industry makes short go-to-market times possible.For prototyping, iterations and first full products, cloud manufacturing is the perfect answer.The same applies to on-demand manufacturing.Only for large-scale production, it makes sense to really push for a large procurement department with the sole responsibility of securing the best deals. Volume is the key here and gives the possibility of negotiating even better prices on your own.Keeping the FocusThe key cloud manufacturing provides, is the one unlocking more resources.At SMEs, the responsibility of finding manufacturers often rests with design engineers. Outsourcing this obligation to a 3rd party leaves more time for the engineers to provide better solutions.<h2>Who Is Cloud Manufacturing For?</h2>Cloud manufacturing may sound intimidating because it&rsquo;s new. Our experience with constantly growing complexity in tech creates associations with steep learning curves.With cloud manufacturing, the contrary is true. The systems are very easy to navigate and make sense of.Therefore, it does not need a lot of resources even in the first steps. The simplicity makes it suitable for a variety of people in need of manufacturing services.BusinessesThis is especially true for SMEs. Large corporations with high volumes can probably get greater discounts working on their own.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1585654433473-Online+laser+cutting+service+US.jpg"><figcaption>Instantly priced parts on Fractory&rsquo;s manufacturing platform</figcaption>For SMEs, outsourcing this job makes a lot of sense. They don&rsquo;t have the production volumes to negotiate for lower prices. Manufacturing platforms can use this leverage for them.Bespoke solutions are the not the future any more, they are the present. With each job requiring new prices, it can amount to a lot of work. Instant pricing helps these companies to stay competitive with cost-efficient procurement processes.Also, prototyping a few parts can be difficult because many manufacturers just reject such jobs. Cloud manufacturing platforms add those parts to larger orders, thus keeping the final price lower.Starting EntrepreneursAs we talked before, cloud manufacturing clearly reduces the go-to-market times.Someone with an idea can now bring it to life without having any previous industry connections. They can still find their way to the best pre-vetted manufacturers nearby or faraway, depending on the final delivery destination.This also makes it possible to, for example, start selling your products world-wide from the get-go. Setting up an online shop is the easy part. Now there is no need to build up a large stock and start transporting those things from the warehouse.Make them nearby your customer and give up on renting a warehouse. This already covers the slightly higher costs of lower-volume production while mitigating the risk of holding large quantities in stock.EngineersSo of course this applies to engineers who have to take care of manufacturing outsourcing working at the aforementioned businesses.But there&rsquo;s another side to it.Any engineer who focuses on providing great results with low costs can now apply the pay-as-you-go system without &ldquo;going anywhere&rdquo;. The quoting system is free to use and helps them optimise the design for cost when comparing materials, thicknesses and different layouts.HobbyistsHobbyists find pretty much the same perks with cloud manufacturing as starting entrepreneurs. Many need only a few pieces for a model plane, a new outdoors BBQ or a doghouse.They can now turn to someone who can definitely assure quality for only a small one-time order.<hr>We hope this was usefull to you. If you are interested in testing such a platform, you can <a href="https://app.fractory.com/auth/register" rel="noopener noreferrer" target="_blank">sign up for free</a><a href="https://app.fractory.com/auth/register" rel="noopener noreferrer" target="_blank"></a> on our website and start uploading your files for instant pricing.&nbsp;

Cloud manufacturing may not be a familiar term to everyone. But there are good reasons to get acquainted with it.

What Is Cloud Manufacturing? And Who Can Benefit From It?

Up to 30% of a compressor&#39;s normal output can be lost through leakage, and poorly maintained equipment will generally be leaking compressed air at around 20% of its total capacity. Leaks may also cause your whole system to lose pressure, leading to less efficient functioning of pneumatic devices, and loss of production output.Not just the compressor, but almost all your system equipment will have its lifespan reduced, as leakages force more frequent cycling and consequent wear. To estimate how much your pneumatic system may be leaking will require running the compressor for a specified time when it is not driving any devices, and measuring the average time it takes to load and unload the system. This loading and unloading occurs as leaks cause pressure drops in the system, and the compressor then cycles on and off to compensate.Not all leakages can easily be prevented, and system design should incorporate some standard allowance for a pressure drop rate per unit time. These parameters could be anticipated in the circuit design, so that appropriate pressure rates and reservoir sizes are determined.<h2>How To Find Leaks In Pneumatic Systems</h2>Sometimes, unnecessary additional compressor capacity is installed to compensate for pressure lost due to leakage. A better and more cost-effective alternative is to introduce a proactive programme of detection and repair, which can bring down your average leak rate to under 10%. The most common areas where leaks can occur include joints, couplings, seals and fittings, as well as hoses and areas which have missing welds or worn packing. Missing O-rings are a common problem, as are improperly installed FRL units and worn point-of-use tools.Air is invisible, of course, so once you&#39;ve calculated the amount of air you&#39;re losing through leakage, you&#39;ll have to find some way of detecting the specific locus of the leak(s). A modern solution to this is ultrasonic detection, by means of an acoustic device to identify the high frequency sounds made by leaking air.Since this type of equipment is commonly portable, it makes the detection of leaks very fast, accurate and versatile. Ultrasound is directional in its transmission, emitting a louder signal the closer it is to the source, so leak sites can be very easily pinpointed by scanning the general area where the equipment is located. Tests can be carried out while equipment is in use, and the detectors are capable of finding many different types of leak. This kind of device is very simple to operate, and it takes only a few minutes to learn how to use it.<h2>What Causes Leaks In Pneumatic Systems?</h2>Leaks are most often found at junction points between the system and end-use pneumatic applications, especially around connectors and joints. Fixing a leak can mean a straightforward tightening-up of a connection, or more complex replacements of faulty components like hoses, fittings, couplings, joints, pipe sections, traps or drains.<h2>Faulty Connectors</h2>Connectors are a very large family of components used to join hoses, tubes or peripheral devices. They need to be chosen carefully and precisely to ensure that a leak-proof joint is achieved, and sealed where necessary. Push-in connectors are very popular due to the simplicity of their installation, but they may be prone to suffer more leakage if a cycle involves frequent connection and disconnection.<h2>Pressure</h2>Leakage may also ensue if the pressure load on valves or connectors exceeds their specified rating. The flow rate of air depends on the pressure differential pertaining across a leakage point, so a lower overall system pressure will help reduce the rate of leakage. If you can stabilise the header pressure of the system at the minimum range that is practical, the leakage rate should also be minimised.<h2>Too Many Connection Nodes</h2>However carefully you seal your connections, if they are pushed to function outside their pressure parameters, some leakage is bound to occur. Furthermore, the more connections there are in the system, the greater the likelihood of multiple leakages leading to a cumulative drop in overall pressure. Increasing the number of connections is not therefore a cost-effective way to expand your pneumatic system, as it also makes the system more complicated, and more difficult to detect leaks.<h2>Wrong Connection Type</h2>Thread types come in many varying styles and sizes, and tend to differ according to their country of origin and use. Connections typically use male and female mating parts, so it&#39;s important to make sure that the thread types match. There are also recommended torque values for most threaded joints, and connections should not be over or under-tightened in relation to these values. Threaded joints should be secured with teflon tape.Seal DegradationExposure of some materials to chemicals may make them degrade. Items such as rubber washers may develop cracks that allow leakage, or thread sealant might be of the wrong type, or not properly applied. All fittings, tubing, hoses, disconnects, etc, should be of high quality, and properly installed with the right thread sealant.<h2>Cylinder Bore Wear</h2>It&#39;s possible for a pneumatic cylinder to suffer excessive wear on the bore if it doesn&#39;t have the proper lubricant. Misalignment or improper mounting can also cause lateral forces to be applied on the bore, which could cause air to leak along the piston&#39;s periphery.<h2>Predictive Leak Prevention</h2>Establishing a good leakage identification and repair programme is critical to maintaining a stable, reliable, efficient and cost effective pneumatic system. Such a programme should involve employee teams in the identification and tagging of leaks, tracking performance, carrying out repairs and verification. Whenever leaks are identified and repairs instituted, the whole system should be reassessed. Scheduled predictive maintenance can help you detect and deal with leaks, so that you save on reactive maintenance and unscheduled downtime. An aggressive programme of leakage prevention and reduction should therefore form part of the overall performance improvement of pneumatic systems.<hr>This post was originally posted on&nbsp;<a data-fr-linked="true" href="https://www.rowse.co.uk/blog/post/how-to-find-leaks-in-pneumatic-systems" rel="noopener noreferrer" target="_blank">www.rowse.co.uk</a>.

If a compressed air system develops a leak, it can waste a lot of energy, especially in a complex automated industrial setting.

How To Find Leaks In Pneumatic Systems

<h2 data-element-id="headingsMap-4-0">Introduction</h2>3D printing technologies based on <a href="https://www.wevolver.com/article/digital.light.processing.3d.printing.explained" rel="noopener noreferrer" target="_blank">DLP printing (Digital Light Processing)</a> are frequently used for fabricating complex objects without tooling and machining. DLP printing involves the light-mediated conversion of a liquid resin containing monomer or oligomer photopolymers to a solid object. This process leverages the versatility of polymer chemistry to make complex objects with programmable optical, chemical or mechanical properties. Versatility underpins the popularity of polymer materials within the 3D printing community, encouraging research in photopolymer chemistry and printing applications. <iframe src="https://www.youtube.com/embed/97ARLiTHjX0?&amp;wmode=opaque&amp;enablejsapi=1&amp;origin=https://www.wevolver.com" allowfullscreen="" class="fr-draggable" style="width: 788px; height: 500px;" frameborder="0" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe>This video explains the process and working of DLP printers in detail - by Professor Bill Hammack, Department of Chemical Engineering, University of Illinois Despite the growing enthusiasm for 3D printing in rapid prototyping applications, implementation in manufacturing environments to produce end-use parts has lagged. Common problems include setting and maintaining minimum specifications, specifically those related to material durability and weathering. Additive manufacturing methods rely on tight synchronicity between hardware, software and chemistry to achieve reproducibility at scale. This article highlights the role of polymerization in the co-development and simultaneous tuning of each component in the DLP process. By understanding the fundamentals of polymerization, developers can simultaneously tune process components, avoiding common pitfalls contributing to part defects, detachment, post-processing and weathering problems.This article is sponsored by polySpectra, which makes functional materials for advanced additive manufacturing. PolySpectra CEO Raymond Weitekamp explained to Wevolver that they've spent thousands of hours and hundreds of thousands of dollars characterizing the thermomechanical properties of dozens of additive manufacturing polymers. For Wevolver readers they are providing a free specification sheet of their newest materials at&nbsp;<a href="http://www.polyspectra.com/wevolver" rel="noopener noreferrer" target="_blank">www.polyspectra.com/wevolver</a> <h2 data-element-id="headingsMap-6-0">Photopolymerization: A multi-stage, dynamic process</h2>A photopolymer is a polymer whose properties alter upon exposure to light. Photopolymers are a liquid mixture containing monomers and oligomers, which can be manipulated to achieve specified physical properties. The process of photopolymerization (also known as photocuring or photo crosslinking) describes the crosslinking of monomers / oligomers within the liquid resin to form a network polymer. This process typically occurs via cationic or radical mechanisms and is mediated by the addition of photoinitiators. Photoinitiators are molecules that convert photolytic energy into reactive species to activate polymerization through specific functional groups.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNTY4Mjk2NjE4NDExLVBob3RvLXBvbHltZXJfc2NoZW1lMSAwMi5wbmciLCJlZGl0cyI6eyJyZXNpemUiOnsid2lkdGgiOjk1MCwiZml0IjoiY292ZXIifX19" style="width: 550px;" class="fr-fic fr-dib">Photopolymerization is an attractive method of curing polymers for 3D printing applications because it can be performed selectively. However, the process of photopolymerization is complex and sensitive to a range of parameters including wavelength, temperature and moisture. The extent and homogeneity of the polymerized cross-linked network is an important determinant in the properties of the final hardened material. Photopolymerization is a multi-stage and dynamic process. <a href="http://rawwerks.com/sla-utility/" rel="noopener noreferrer" target="_blank">Photopolymerization kinetics</a> is described as a “working curve”, mapping cure depth (depth to which light induces polymer crosslinking) as a function of light exposure at different wavelengths. Critical exposure (Y-intercept on the working curve) is defined as the minimum light exposure required for the onset of curing. The behaviour of the photopolymer under specified light exposure conditions (wavelength, power, exposure time and velocity) affect the printing process. There are a wide range of photopolymers available, responding to wavelengths in the UV (190-400 nm), visible (400-700 nm) and IR ranges (700-1000 nm). Light of different wavelengths penetrate materials to different cure depths. <img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNTY4Mjk4MzAwNTYzLVBSLTQ4LVdDLnBuZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=">An example of a Working Curved that shows the relation between UV light dose and curing depth of the resin. Image courtesy Polyspectra. <iframe src="https://www.youtube.com/embed/Lw3BY2_yGVU?&amp;wmode=opaque&amp;enablejsapi=1&amp;origin=https://www.wevolver.com" allowfullscreen="" class="fr-draggable" style="width: 788px; height: 470px;" frameborder="0" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe>This video explains how the working curve impacts the 3D print and how to find the correct settings - by Autodesk Ember <h2 data-element-id="headingsMap-8-0">Photopolymerization: A fundamental process in DLP printing</h2>The dynamic nature of photopolymerization suggests that it is a non-binary process. In DLP printing, light is projected into the polymer resin forming a 2D image. This simultaneously exposes all the designated regions within a polymer layer. The overall printing time is reduced through compared to rastered stereolithography, due to the parallelization of the photocuring process. The projected 2D image is composed of pixels, which become voxels when translated into three dimensions. This has led to the misconception that DLP is an essentially digital binary processtechnology and that print resolution is purely a function of printer hardwarethe DLP optics. In reality, voxels contain photopolymers that are fluxing between stages of the photopolymerization process: going from liquid to their gel point and then on towards their full cross-linking density.<iframe src="https://www.youtube.com/embed/5qTAmPrHLow?&amp;wmode=opaque&amp;enablejsapi=1&amp;origin=https://www.wevolver.com" allowfullscreen="" class="fr-draggable" style="width: 788px; height: 470px;" frameborder="0" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true" data-headingsmap-frameid="1370"></iframe>This video shows the impact of voxels on the 3D print and how printers can actually achieve resolutions smaller than the nominal resolution of the DLP projector - by Autodesk Ember. This can influence the 3D printing process in several ways. Firstly, printing speed should be calibrated to account for photopolymerization kinetics. If not, voxels may expand beyond their digitally defined physical space, reducing feature resolution of the finished part. Further, photopolymerization may cause shrinkage in the hardened polymer. Shrinkage coupled with cycles of thermal expansion and contraction experienced during the printing process may induce stressinduces stresses on the part, . These stresseswhich can manifest in warping or layer splitting or separation in the finished object. Strategies to mitigate these effects include tuning both software and hardware to select appropriate exposure protocols (velocity and speed) and control environmental influences (temperature and humidity). Finally, the cure depth is an important parameter to consider when implementing a DLP printing protocol. Cure depth directly impacts the z- axis settings of the printer. It may also influence the selection of printing parameters such as print velocity.Recommended reading:&nbsp;<a href="https://www.wevolver.com/article/digital.light.processing.3d.printing.explained" rel="noopener noreferrer" target="_blank">Digital Light Processing 3D printing explained</a><h2 data-element-id="headingsMap-10-0">Detachment: Building and breaking interactions between materials and hardware</h2>3D objects are rendered through the sequential hardening of photopolymer layers onto a substrate (known as a build plate). An essential step in any 3D printing process is the detachment of the finished part from the substrate. This step can prove problematic, as the printing process can induce suction forces, securing the part to the substrate. Numerous separation mechanics have been described to overcome these suction forces. Examples include tilting the resin tray and peeling the part off or using a sliding mechanism. Building the part on a flexible window, to which pressure may be applied to break suction forces is also a common method.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNTY4MzU3NDgwMzU4LUNhcmJvbiBCZWQuanBnIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==">A print (with support structure) attached to a print bed after printing. Source: Carbon 3DBuilding an oxygen permeable window within the substrate allows oxygen to access the photopolymer directly in contact with the substrate. This creates a depletion zone of inactive resin which does not adhere to the substrate, facilitating part removal. However, this method is only suitable for photopolymers which are quenched by oxygen, such as acrylates and methacrylates. An alternative strategy is to modify the viscosity of the liquid photopolymer resin. Low viscosity solutions enable higher printing speeds and concomitant reduction in the suction forces adhering the part to the substrate. This highlights an important aspect of 3D printing; the relationship between the photopolymer materials and the design of the printer hardware. It is widely recognised that surface adhesion is important to provide a foundation for the object to build upon. Consequently, the materials within the hardware and the finished printed object should be compatible.<h2 data-element-id="headingsMap-11-0">Post-processing: The significance of photopolymerization in scaling production</h2>DLP printing found initial application as an instrument for rapid prototyping in research settings. Introducing DLP printing into manufacturing settings has been slower due to problems with scaling production, reproducibility and part quality. The co-development of printing processes and materials is not only critical during the initial build process. Photopolymerization kinetics also affect post-processing of end-use parts. The acceptance of 3D printing into manufacturing settings has been restricted by extensive post-processing requirements including:<ul><li>Removal of the support structure (onto which the part is fabricated).</li><li>Part cleaning to remove debris and residual materials.</li><li>Post-curing (usually thermal or optical) to completely harden certain materials.</li><li>Part finishing (such as sanding, painting or varnishing) to remove the “boxy” surface finish characteristic of DLP printing.</li></ul><img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNTY4MzU3NTQ3NzY2LXBvc3QgcHJvY2Vzc2luZy5qcGciLCJlZGl0cyI6eyJyZXNpemUiOnsid2lkdGgiOjk1MCwiZml0IjoiY292ZXIifX19" style="width: 766px;" class="fr-fic fr-dib">Rinsing off resing, removing support, and curing with UV light. Source: FormlabsPost-processing steps are often performed in small batches under carefully controlled conditions. These processes can be difficult to automate, adding substantial time and cost to the production process. Advances in automation are ongoing, with some companies utilising robotics to automate assembly lines integrating 3D printers with post-processing equipment. Advances in printing hardware and software enabling automated monitoring could enable DLP printing at scale. However, the widespread implementation of automated processing lines has yet to be realised. Post-processing requirements are heavily dependent on photopolymer characteristics, with some materials requiring more extensive modification than others. Strategies to streamline operations should include selecting materials with limited post-processing requirements yet withstand weathering processes to maintain durability.<h2 data-element-id="headingsMap-12-0">Conclusion</h2>The combination of pivotal developments in 3D printing hardware, software and materials has paved the way towards the implementation in prototyping and manufacturing. With an increased awareness of the importance of co-developing each component simultaneously, the development of new applications for 3D printing of end-use parts is slowly becoming a reality. The relevance of DLP printing in the manufacturing sector will depend heavily on the ability to cost-effectively produce end-parts that are durable. The dynamic nature of photopolymerization continues throughout the lifetime of a part. The weatherability of hardened polymers is an important determinant of part durability, specifically the ability to maintain toughness and impact strength over time. By understanding the kinetics of photopolymerization and thermodynamic properties of the resulting polymer networks, developers can select materials to mitigate common problems, yet maintain desired properties throughout the lifetime of a part. <hr>This article was sponsored by&nbsp;<a href="http://polyspectra.com/wevolver" rel="noopener noreferrer" target="_blank">polySpectra</a>. polySpectra makes functional materials for advanced additive manufacturing in Berkeley, California, USA. They use light-activated catalysts to 3D print advanced functional materials. Polyspectra's platform enables them to deliver materials with a broad spectrum of tailored properties from a single chemical system.For Wevolver readers polySpectra is providing a free specification sheet of their newest materials at&nbsp;<a href="http://www.polyspectra.com/wevolver" rel="noopener noreferrer" target="_blank">www.polyspectra.com/wevolver</a>

DLP (Digital Light Processing) 3D printing uses photopolymerization to create 3D objects. Understanding the photopolymerization process can help you mitigate common problems that make your prints fail or that reduce print quality.

DLP 3D Printing: Understanding process and materials enables you to prevent production problems

What is DLP is a 3D printing? This article aims to provide an in-depth understanding of DLP 3D printing, its working principles, advantages, limitations, and diverse applications in various sectors.

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