Infill and support issues with 3D PLA prints

Top: The left one has a rectilinear fill, the right a square grid fill. Notice the fill on the left has buckled part way up - this piece is too tall for that type. While the grid fill on the right is far more stable, it is not as easily removed (although it can stay in place here).
Middle: The piece on the right printed in half the time because the only fill needed is at the bottom. The fill is rectilinear and easily removed - it affects the smoothness of the surfaces but they are not a finished ones so it does not matter. However that method is risky, notice the failed print on the lower right - upward pull of the flat section pulled it away. This happened twice more so I chalked up the one success to luck.
Bottom: Took about 16 hours. Like others, the grid of printed support out past the edge - that part has to be cut away with a sharp blade knife to enable mating with the other pieces.

Related Pictures

Warping during a large print - one solution is multiple pieces

I am attempting to 3D print a shell for making a rubber block mold (the base of a Medalta ball pitcher). This is almost at the limit of what will fit on the print-bed. It would take 30 hours. But at about 10 hours it did this: All four outer corners warped upwards. I have a larger printer but it will do the same thing! What is the solution? Cut it up into smaller pieces and print each of them at the best orientation (bottom right), this saves significant printing time and achieves better quality. For this piece, the inside surface on the center section is most important, printing it upright with printed support took about 4 hours. All the other pieces print in about 1 hour each. Tape (either masking or MicroPore) can be used effectively to hold everything together for super-gluing or epoxy. Much of the tape can be left in place during the pour. The rubber form has thin 1cm walls, but these are supported by side-rails when plaster is poured.

The v2 ball pitcher is way too big to 3D print. What now?

This is a Medalta Potteries medium-sized ball pitcher block mold, version 2.0 - it has a more oval body shape. Upper left is the top section (actually, it is half of the top section, a base will fit on to create a three-piece working mold. There is to 3D print something this large in one piece in a consumer 3D printer. Even if it did it would require 50 hours of print time! Also, working surface quality is affected by the orientation of printing (especially if a surface is down-facing and on top of printed support). Further, a large print would almost certainly warp and corner-lift during printing. Cutting it into four pieces and hollowing them individually (in the CAD software, lower right) solved all the problems. Each of the pieces is still quite large, taking 10+ hours to print. But they can each be hollowed individually and rotated to the optimum position for the best finished surface (and print speed). It is amazing how well these four pieces fitted together. This approach really paid off because I made a mistake - and I only needed to reprint one of the pieces!

Assorted problems with 3D printing PLA molds

I am 3D printing a block mold - rubber will be poured into it to make a case mold for beer.bottles. It is an amazing process but there are still issues to deal with:
-Stringing (top left). This usually happens when the nozzle is running too hot. This new batch of filament needs a slightly lower temperature, so I adjusted from 215 to 207.
-Size constraints: This is too big to print as one mold so it has to be done in multiple sections (two mains, two end-caps). Pieces fit precisely and can be glued or taped.
-Experience shows where glue, tape or special brackets (e.g. corners lower left) are needed.
-Special tools must be made (lower left is a clip-insertion tool).
-Corner lifting: Happens mid-print (the large thin pads on the lower right are to prevent that).
-Pressure bowing: The stabilizer bars spanning the two mid-pieces (lower left) and the triangular lip (upper right) keep that edge straight despite pressure from the liquid rubber inside.

Links

Typecodes	3D printing problems 3D printing for mold making in ceramics requires determination and skill. And a memory for the many problematic techniques.
Glossary	Infill and Support Infill and support are structural elements that 3D slicer software uses (e.g. to fill the interior of solid parts or support contours over empty space)

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