The small patch of chain mail early in the M2’s PETG conversion had links with four threads along each bar:

Dropping the bars to 3.3 threads wide produced a slightly smaller patch:

The bars on the platform are 1.6 mm = 4 threads wide, because I’ve forced the thread width to 0.40 for that layer:

The remainder are closer to 1.4 mm = 3.3 threads, with the preview showing Slic3r allowed a narrow gap that doesn’t appear in real life:

What’s important about this is that the bridging worked perfectly: all the links emerged free of their neighbors and the patch flexed along both axes.

I tried this on one layer of Elmer’s White Glue, diluted 1:3 with water, and the links bonded firmly. I’d had some trouble with a few links popping off the usual hairspray after the first few layers, so I decided to try something different.

The fine hair strands have mostly Gone Away, perhaps due to using Concentric infill.

All in all, PETG looks pretty good, even if it’s just as hard to photograph as red PLA.

Update: You may prefer the source code as a GitHub gist.

The OpenSCAD source code:

// Chain Mail Armor Buttons // Ed Nisley KE4ZNU - December 2014 Layout = "Build"; // Link Button LB Joiner Joiners Build PillarMod //------- //- Extrusion parameters must match reality! // Print with 1 shell and 2+2 solid layers ThreadThick = 0.25; ThreadWidth = 0.40; HoleWindage = 0.2; Protrusion = 0.1; // make holes end cleanly function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit); //------- // Dimensions //- Set maximum sheet size SheetSizeX = 55; // 170 for full sheet on M2 SheetSizeY = 55; // 230 ... //- Diamond or rectangular sheet? Diamond = false; // true = rotate 45 degrees, false = 0 degrees for square BendAround = "X"; // X or Y = maximum flexibility *around* designated axis Cap = true; // true = build bridge layers over links CapThick = 4 * ThreadThick; // flat cap on link: >= 3 layers for solid bridging Armor = true && Cap; // true = build armor button atop (required) cap ArmorThick = IntegerMultiple(2.0,ThreadThick); // height above cap surface ArmorSides = 4; ArmorAngle = true ? 180/ArmorSides : 0; // true -> rotate half a side for best alignment //- Link bar sizes BarThick = 3 * ThreadThick; BarWidth = 3.3 * ThreadWidth; BarClearance = 4 * ThreadThick; // vertical clearance above & below bars VertexHack = 0; // 0 = no, 1 = slightly reduce openings to avoid coincident vertices //- Compute link sizes from those values //- Absolute minimum base link: bar width + corner angle + build clearance around bars // rounded up to multiple of thread width to ensure clean filling BaseSide = IntegerMultiple((4*BarWidth + 2*BarWidth/sqrt(2) + 3*(2*ThreadWidth)),ThreadWidth); BaseHeight = 2*BarThick + BarClearance; // both bars + clearance echo(str("BaseSide: ",BaseSide," BaseHeight: ",BaseHeight)); //echo(str(" Base elements: ",4*BarWidth,", ",2*BarWidth/sqrt(2),", ",3*(2*ThreadWidth))); //echo(str(" total: ",(4*BarWidth + 2*BarWidth/sqrt(2) + 3*(2*ThreadWidth)))); BaseOutDiagonal = BaseSide*sqrt(2) - BarWidth; BaseInDiagonal = BaseSide*sqrt(2) - 2*(BarWidth/2 + BarWidth*sqrt(2)); echo(str("Outside diagonal: ",BaseOutDiagonal)); //- On-center distance measured along coordinate axis // the links are interlaced, so this is half of what you think it should be... LinkOC = BaseSide/2 + ThreadWidth; LinkSpacing = Diamond ? (sqrt(2)*LinkOC) : LinkOC; echo(str("Base spacing: ",LinkSpacing)); //- Compute how many links fit in sheet MinLinksX = ceil((SheetSizeX - (Diamond ? BaseOutDiagonal : BaseSide)) / LinkSpacing); MinLinksY = ceil((SheetSizeY - (Diamond ? BaseOutDiagonal : BaseSide)) / LinkSpacing); echo(str("MinLinks X: ",MinLinksX," Y: ",MinLinksY)); NumLinksX = ((0 == (MinLinksX % 2)) && !Diamond) ? MinLinksX + 1 : MinLinksX; NumLinksY = ((0 == (MinLinksY % 2) && !Diamond)) ? MinLinksY + 1 : MinLinksY; echo(str("Links X: ",NumLinksX," Y: ",NumLinksY)); //- Armor button base ButtonHeight = BaseHeight + BarClearance + CapThick; echo(str("ButtonHeight: ",ButtonHeight)); //- Armor ornament size & shape // Fine-tune OD & ID to suit the number of sides... TotalHeight = ButtonHeight + ArmorThick; echo(str("Overall Armor Height: ",TotalHeight)); ArmorOD = 1.0 * BaseSide; // tune for best base fit ArmorID = 10 * ThreadWidth; // make the tip blunt & strong //------- module ShowPegGrid(Space = 10.0,Size = 1.0) { RangeX = floor(95 / Space); RangeY = floor(125 / Space); for (x=[-RangeX:RangeX]) for (y=[-RangeY:RangeY]) translate([x*Space,y*Space,Size/2]) %cube(Size,center=true); } //------- // Create link with armor button as needed module Link(Topping = false) { LinkHeight = (Topping && Cap) ? ButtonHeight : BaseHeight; render(convexity=3) rotate((BendAround == "X") ? 90 : 0) rotate(Diamond ? 45 : 0) union() { difference() { translate([0,0,LinkHeight/2]) // outside shape intersection() { cube([BaseSide,BaseSide,LinkHeight],center=true); rotate(45) cube([BaseOutDiagonal,BaseOutDiagonal,(LinkHeight + 2*Protrusion)],center=true); } translate([0,0,(BaseHeight + BarClearance + 0*ThreadThick - Protrusion)/2]) intersection() { // inside shape cube([(BaseSide - 2*BarWidth), (BaseSide - 2*BarWidth), (BaseHeight + BarClearance + 0*ThreadThick + VertexHack*Protrusion/2)], center=true); rotate(45) cube([BaseInDiagonal, BaseInDiagonal, (BaseHeight + BarClearance + 0*ThreadThick + VertexHack*Protrusion/2)], center=true); } translate([0,0,((BarThick + 2*BarClearance)/2 + BarThick)]) // openings for bars cube([(BaseSide - 2*BarWidth - 2*BarWidth/sqrt(2) - VertexHack*Protrusion/2), (2*BaseSide), BarThick + 2*BarClearance - Protrusion], center=true); translate([0,0,(BaseHeight/2 - BarThick)]) cube([(2*BaseSide), (BaseSide - 2*BarWidth - 2*BarWidth/sqrt(2) - VertexHack*Protrusion/2), BaseHeight], center=true); } if (Topping && Armor) translate([0,0,(ButtonHeight - Protrusion)]) // sink slightly into the cap rotate(ArmorAngle) cylinder(d1=ArmorOD,d2=ArmorID,h=(ArmorThick + Protrusion), $fn=ArmorSides); } } //------- // Create split buttons to join sheets module Joiner() { translate([-LinkSpacing,0,0]) difference() { Link(false); translate([0,0,BarThick + BarClearance + TotalHeight/2 - Protrusion]) cube([2*LinkSpacing,2*LinkSpacing,TotalHeight],center=true); } translate([LinkSpacing,0,0]) intersection() { translate([0,0,-(BarThick + BarClearance)]) Link(true); translate([0,0,TotalHeight/2]) cube([2*LinkSpacing,2*LinkSpacing,TotalHeight],center=true); } } //------- // Build it! //ShowPegGrid(); if (Layout == "Link") { Link(false); } if (Layout == "Button") { Link(true); } if (Layout == "LB") { color("Brown") Link(true); translate([LinkSpacing,LinkSpacing,0]) color("Orange") Link(false); } if (Layout == "Build") for (ix = [0:(NumLinksX - 1)], iy = [0:(NumLinksY - 1)]) { x = (ix - (NumLinksX - 1)/2)*LinkSpacing; y = (iy - (NumLinksY - 1)/2)*LinkSpacing; translate([x,y,0]) color([(ix/(NumLinksX - 1)),(iy/(NumLinksY - 1)),1.0]) if (Diamond) Link((ix + iy) % 2); // armor at odd,odd & even,even points else if ((iy % 2) && (ix % 2)) // armor at odd,odd points Link(true); else if (!(iy % 2) && !(ix % 2)) // connectors at even,even points Link(false); } if (Layout == "Joiner") Joiner(); if (Layout == "Joiners") { NumJoiners = max(MinLinksX,MinLinksY)/2; for (iy = [0:(NumJoiners - 1)]) { y = (iy - (NumJoiners - 1)/2)*2*LinkSpacing + LinkSpacing/2; translate([0,y,0]) color([0.5,(iy/(NumJoiners - 1)),1.0]) Joiner(); } } if (Layout == "PillarMod") // Slic3r modification volume to eliminate pillar infill translate([0,0,(BaseHeight + BarClearance)/2]) cube([1.5*SheetSizeX,1.5*SheetSizeY,BaseHeight + BarClearance],center=true);

#1 by

Joshon 2015-04-02 - 20:16I’ve found that desaturating pictures of red PLA works best – yes, you lose the color obviously, but you can see a

lotmore detail, which, when showing off sample prints or print defects/artifacts, is more important than the color anyway.#2 by Ed on 2015-04-02 - 20:25

Aye! I

finallytried some variations on the desaturation technique I used for those pix on the MG forum a while ago; it’ll show up next week.For critical pix, the future looks downright monochrome!