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3D Printing

The subject of potential health risks in relation to 3D printing has been mostly overlooked. However, this is beginning to change thanks, in no small part, to the efforts of 3DPrintClean, a USA-based manufacturer of safety enclosures for fused deposition modeling (FDM)/fused filament fabrication (FFF) and stereolithography (SLA) desktop 3D printers.

Founded in mid-2015 by the inventor of said enclosures, James Nordstrom, 3DPrintClean has since been on a mission to educate those industry sectors utilizing these printers on their potentially harmful emissions, namely ultrafine particles (UFPs) and volatile organic compounds (VOCs).

A lot of 3D printers incorporate a high-efficiency particulate air (HEPA) filter, although it needs to be borne in mind that these are only capable of capturing particles of 0.1µm or 300 nanometers and above in size and therefore not the UFPs that are 0.1µm or 100 nanometers and below.

3DPrintClean expects to begin shipping the latest models of its enclosures—the Model 660 and Model 870—in August, 2017. The only real difference between the two is size. The Model 660 is designed to house smaller, desktop-sized printers, affording internal dimensions of 600 (w) x 810 (h) x 600 (d) millimeters, and the Model 870 is for printers that have larger build platforms, measuring 810 (w) x 810 (h) x 810 (d) millimeters.

The Model 660 and Model 870 incorporate many new features requested by the owners of their predecessors. The most important of these are a significantly larger filter, more powerful blower motor and customized rubber gasket seals.

The filter on the new models is 19 x 19 inches, whereas on the previous models it was just 5 x 7 inches. Recommended usage of the 19 x 19-inch filter is one year, so considerably longer than the 90 days given for the 5 x 7-inch filter (these timescales are based on the printer being used on a daily basis, so c. 10-12 hours). It also goes without saying that a 19 x 19-inch filter is going to be considerably more effective at capturing UFPs and VOCs.

The filter comprises two filters, one for UFPs and the other for VOCs, that are custom produced one on top of the other. The enclosure performs a calendar year countdown from the date that the original filter is first used and notifies the user 30 days prior to its advised replacement.

A 150 CFM (cubic feet per minute) blower motor complements the larger filter, being three times as strong as the blower motor on the old enclosures and therefore capable of circulating the contaminated air more quickly. Together, the new filter and blower motor are said to reduce filtration times considerably.

Class A Surfacing

‘A’ Class surface definition. Class ‘A’ surface refers to those surfaces which are visible in a product. This service is primarily used in the automotive environment and increasingly in consumer goods. It is a requirement where aesthetics have a significant contribution. E.g. the exterior of automobiles are deemed Class-‘A’.

Why would you require Class ‘A’ surfacing. We all know that today’s products are not only designed considering the functionality but special consideration is given to their form and aesthetics which is crucial in the perception and reality of a quality product to the consumer. This quality is only possible with high-class finish and good forms. This is the reason why in design industries, Class ‘A’ surface are given more importance.

If you would like to discuss how the PES team can deliver Class ‘A’ Surfacing to your design or product and how this service could benefit you, or you would just like more information. Please contact us for a chat or e-mail and we will do our very best to support your requirements.

These surfaces are predominantly used in the automotive industry where aesthetic finish is crucial, however class ‘A’ surfacing is applied to many other sectors.

Curvature continuity: It is the continuity between the surfaces sharing the same boundary. Curvature continuity means that at each point of each surface along the common boundary has the same radius of curvature and therefore the boundaries have been blended so no physical joint is present or visible.

Literal meaning: A class ‘A’ surface refers to those surfaces, which are ‘curvature’ continuous to each other at their respective boundaries. Curvature continuity means that at each “point” of each surface along the common boundary has the same radius of curvature.

This is different to surfaces having;

  • Tangent continuity – which is directional continuity without radius continuity – like fillets.
  • Point continuity – only touching without directional (tangent) or curvature equivalence.

CAD Comparison

CAD Comparison is one of the most important and least understood areas in design and engineering today. Comparison software automatically evaluates the exact degree to which two models have the same geometry, provides a method to authenticate that the two models are the same for all practical purposes and determines how well a grouping of points fits to an existing 3D CAD model. TransMagic’s CAD Comparison solution is MagicCheck.

A Bigger Problem than Perceived

How does an estimator or designer quickly check that the revision the customer just sent actually only has the specified changes, and that there are no ‘surprise changes’ elsewhere in the file? How does purchasing make sure the part they ordered is the same as the part they received? When translations have taken place for downstream analysis or machining, how does a company guarantee that the files are actually the same, within a specific tolerance? Without the answer, the risk is that downstream there will be expensive surprises. In fact, one study found 15% of the time, CAD errors were not found until parts had already been cut1.

Easy Part to Part Comparison

magic-check-375wThe most basic use of CAD comparision software is to compare two parts; how easily is the comparison achieved? Can the software allow the user to see inside the parts where changes may be hiding? Are degrees of tolerance up to six places available? Will the software display a color plot showing all changed features and their degree of change? Is a report generated automatically? The figure at right shows an example of two parts being overlaid and compared; note the color ‘heat map’ that helps the eye distinguish geometry that is unique to each revision, as well as how far out of tolerance each variation is.

Part Authentication

How can you be certain that the part you translated to STEP for your analysis is within a reasonable tolerance to the original part dimensions? This is a problem that many aerospace firms are forced to deal with, and a problem that companies such as Boeing take a keen interest in. Suppliers to Boeing and other aerospace OEMs are tasked with proving that their derived models have not significantly changed from the original sent them by the customer, via Boeing validation document D6-51991. CAD comparison software can also authenticate two parts, comparing the original master model and the derived check model to determine how close they are in hundredths, thousandths, or ten-thousandths of an inch or millimeter.

Point to Part Comparison

Point-To-Part-ComparisonCMM and other scanning devices return a list of X, Y, & Z points of physical prototypes or production parts. Using Point to Part Comparison, these points can be compared to the original CAD master model to see how closely the physical model matches. In the figure at right, a colored ‘heat map’ shows which points are within the specified tolerance (anything green is within tolerance), which points penetrate into the master model envelope (warm shades such as red), and which points are outside of the part envelope (cool colors, i.e., blue).

Know your Data

TransMagic MagicCheck not only compares and authenticates part-to-part and point-to-part geometry, but it provides a single-button report, specifying where the geometry is within tolerance and out of tolerance, complete with custom views and ‘heat maps’ views. With MagicCheck, you’ll know when your customers have made additional ‘undocumented’ changes to part geometry. You’ll be empowered to authenticate that your working geometry is within tolerance to the master model geometry, thus enabling you to go after a wider range of customers. And you’ll be able to compare scans and CMM data to the original part, in order to find and effect adjustments to the manufacturing process so that final products conform to the right dimensions & assemblies go together properly.

3D Scanning

Creaform has an impressive range of handheld scanners that can record hundreds of thousands of points of data every second with up to 30 micron accuracy, but how would we go about scanning the human body? The high accuracy and tracking targets are great for scanning large objects to perform high accuracy inspections and for reverse engineering, but you don’t really need that kind of accuracy for the human body. You also don’t want that kind of rigorous accuracy on the human body because it is not a hard, rigid piece of plastic or metal. If you are scanning someone’s foot, for example, and they have a little twitch, the scanner would pick that up and the data after that point would be shifted for the rest of the collected data causing bad scans.

Thankfully Creaform has a solution to this problem and provides the correct tool for any job you might have. This problem can be solved with the GoScan50. The GoScan50 has a specific setting in it to allow for semi-rigid tracking. What this option does is it loosens up the algorithm a bit to compensate for small movements on the part/person being scanned. Now the person can’t shift in any dramatic way or else the scanner will just start picking up the new data as a fresh surface to scan (i.e. if you are scanning a hand and they move their thumb out to the side), but we will address this more later.

The second feature of the GoScan50 for scanning people is its ability to track natural features on the object, without the need for tracking targets. This makes for a very powerful tool to scan people without needing to add target dots at all.

Third, those abilities coupled with the GoScan50’s large scan area of 15inX15in, allows you to capture a large section at a time, and track a large area of virtual targets so the scanner does not get lost. As you can see in this picture, the large area of, eye-safe, structured light that the scanner is projecting out. This makes scanning a person or limb very quick to get done so they do not have to hold a position for any excessive amount of time.

The final thing that helps with scanning of anatomy or anything that might move on you is the capabilities of the software to help correct for any errant data and bad frames that might be collected. Within VXElements you can select a section of the scan and every frame associated with the selection can be deleted. So say you are scanning a hand to make a custom glove or a foot to make some custom shoes/boots and they shift a finger or the entire hand for a second.

In this picture, the thumb moved dramatically and was picked up as new data. This is just during the live scan process and is before the final image is rendered (this makes it much easier on the computer to collect the data).

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