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This study aims to evaluate the color accuracy of HP Jet Fusion 580 3D printing, comparing 3D-printed outcomes against original digital input colors.

A custom cyan, magenta, yellow and black (CMYK) and red, green, blue (RGB) color chart was applied to the top, bottom and side surfaces of a 3D model. Four of each model were 3D-printed on a HP Jet Fusion 580, and half the samples were finished with a cyanoacrylate gloss surface finish, while half were left in raw form. A spectrophotometer was used to document CIELAB (L*a*b*) data, and comparisons made to the original input colors, including calculation of ΔE.

The CMYK samples were significantly more accurate than RGB samples, and grayscale samples in both color spaces were the most accurate of all. Typically, CMYK swatches were darker than the input values, and gloss samples were consistently darker than raw samples. The chromaticity (a*b*) range was found to be significantly smaller than what can be achieved digitally, with highly saturated colors unable to be produced by the printer.

This is the first study, to the best of the authors’ knowledge, to characterize the full color spectrum possible with the HP Jet Fusion 580, recommending that designers use the CMYK color space when applying colors and textures to 3D models. A quick-reference color chart has been provided; however, it is recommended that future research focus on developing a color management profile to better map digital colors to the capabilities of the printer.

Orange peel formation remains to be understood clearly because it is difficult to directly observe a laser-sintered process in a partcake. Therefore, this study aims to provide insight into the orange peel formation mechanism through the nondestructive observation of laser-sintered specimens and their surrounding powders.

This study observed polyamide 12 powder in the vicinity of a laser-sintered specimen via X-ray computed tomography (CT) scanning. The specimen for nondestructive observation was 3D modeled in a hollow box using 3D CAD software. The boxes built using a laser-sintering system contained unsintered surrounding powder and sintered specimens. The box contents were preserved even after the boxes were removed from the partcake. After X-ray CT scanning, the authors broke the boxes and evaluated the unevenness formed on the specimen surface (i.e. the orange peel evaluation).

Voids (not those in sintered parts) generated in the powder in the vicinity of the specimen triggered the orange peel formation. Voids were less likely to form in the build with a 178.5° powder bed than in the build with a 173.5° powder bed. Similarly, the increment in laser energy density effectively suppressed void formation, although there was a tradeoff with overmelting. Thin-walled parts avoided void growth and made the orange peel less noticeable.

To the best of the authors’ knowledge, this study is the first to observe and understand the relationship between voids generated in the powder in the vicinity of sintered parts and orange peel formation.

Recent Trailing Edge articles have discussed typefaces and graphics. This column discusses putting it all together: economical desktop publishing. There has never been a better time for libraries to become desktop publishers, and some will find that doing so requires no new software or hardware. The author discusses changes that have made desktop publishing such an appealing and reasonably‐priced proposition in 1994 and some of your options for getting started and moving on. He brings the typeface discussion up to date with a startling recent development and defines the difference between true desktop publishing and the spare‐no‐expense field that the “desktop publishing” magazines cover. A sidebar notes a series of desktop publishing workshops that the author is offering as part of LITA's regional institutes program. Finally, the author adds notes on the personal computing literature for January to March 1994, now including some Macintosh magazines and, soon, CD‐ROM/multimedia publications.

The purpose of this paper is to give an insight into relevant aspects of 3D printing of clay paste enhanced with scrap polymer powder which have not been investigated by previous studies. Specifically, the geometrical features of the deposited lines, dimensional accuracy of benchmarks and mechanical properties of printed parts are investigated.

Firstly, the 3D printer is used to deposit lines of the paste under various combinations of material composition and process parameters. 3D scanning is used to measure their dimensional and geometrical errors. The results are elaborated through statistics to highlight the role of material and processing conditions. Then, four benchmark parts are printed using materials with different percentages of polymer powder. The parts are scanned after each step of the post-processing to quantify the effects of printing, drying and melting on dimensional accuracy. Finally, drop weight tests are carried out to investigate the impact resistance of specimens with different powder contents.

It is found that the quality of deposition varies with the printing speed, nozzle acceleration and material composition. Also, significant differences are observed at the ends of the lines. Materials with 10 Wt.% and 40 Wt.% of powder exhibit relevant shape variations due to the separation of phases. Accuracy analyses show significant deformations of parts at the green state due to material weight. This effect is more pronounced for higher powder contents. On the other hand, the polymer reduces shrinkage during drying. Furthermore, the impact test results showed that the polymer caused a large increase in impact resistance as compared to pure clay. Nonetheless, a decrease is observed for 40 Wt.% due to the higher amount of porosities.

The results of this study advance the knowledge on the 3D printing of clay paste reinforced with a scrap polymer powder. This offers a new opportunity to reuse leftover powders from powder bed fusion processes. The findings presented here are expected to foster the adoption of this technique reducing the amount of waste powder disposed of by additive manufacturing companies.

This study offers some important insights into the relations between process conditions and the geometry of the deposited lines. This is of practical relevance to toolpath planning. The dimensional analyses allow for understanding the role of each post-processing step on the dimensional error. Also, the comparison with previous findings highlights the role of part dimensions. The present research explores, for the first time, the impact resistance of parts produced by this technology. The observed enhancement of this property with respect to pure clay may open new opportunities for the application of this manufacturing process.

This is our report on this first international assembly of Aircraft Maintenance and Engineering, held in Zurich 6th–9th February 1979. This was AIRMEC 79 — and, as was foreseen in our Comment in the January issue, the significance of this innovation among aviation occasions was taken up by thirty‐six countries who sent 276 delegates to the convention, which was supported by the Exhibition, attracting 112 exhibitors from 17 countries. There is every chance that this event will take its place with Farnborough, Paris and Cranfield as a regular feature of the aviation scene and of considerable interest to all engaged in aircraft maintenance. The organisers did announce at the end of that Show that AIRMEC 81 would take place, again in Zurich, in February of that year. And perhaps it is interesting to comment at this stage about the decision to return to Zurich. While it might be said that the event was a success, the fact that the convention was held in a venue separate from the Exhibition, did have some disadvantages and the consensus among the exhibitors was that this did discourage many of the 2260 in attendance from really taking in the Exhibition. Perhaps the only exception to this were the Chinese whose delegation spent almost all of every day in the Exhibition halls, visiting every stand and spending considerable time at each one.

During the great post–World War II economic expansion, modernization theorists held that the new American capitalism balanced mass production and mass consumption, meshed profitability with labor's interests, and ended class conflict. They thought that Keynesian policies insured a near full-employment, low-inflation, continuous growth economy. They viewed the United States as the “new lead society,” eliminating industrial capitalism's backward features and progressing toward modernity's penultimate “postindustrial” stage.⁷ Many Americans believed that the ideal of “consumer freedom,” forged early in the century, had been widely realized and epitomized American democracy's superiority to communism.⁸ However, critics held that the new capitalism did not solve all of classical capitalism's problems (e.g., poverty) and that much increased consumption generated new types of cultural and political problems. John Kenneth Galbraith argued that mainstream economists assumed that human nature dictates an unlimited “urgency of wants,” naturalizing ever increasing production and consumption and precluding the distinction of goods required to meet basic needs from those that stoke wasteful, destructive appetites. In his view, mainstream economists’ individualistic, acquisitive presuppositions crown consumers sovereign and obscure cultural forces, especially advertising, that generate and channel desire and elevate possessions and consumption into the prime measures of self-worth. Galbraith held that production's “paramount position” and related “imperatives of consumer demand” create dependence on economic growth and generate new imbalances and insecurities.⁹ Harsher critics held that the consumer culture blinded middle-class Americans to injustice, despotic bureaucracy, and drudge work (e.g., Mills, 1961; Marcuse, 1964). But even these radical critics implied that postwar capitalism unlocked the secret of sustained economic growth.