Instructions:FDM Printing

for all

John has photos if you want to help him add them. Broken links on the Prusa and Raise3D pages?

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FDM 3D printing heats plastic until it is soft enough to extrude through a nozzle. The soft plastic is then deposited layer-by-layer on the bed until the object is complete.

North Forge has several FDM 3D printers available:

Bambu Labs P1S FDM 3D Printer

Bambu Labs P1S FDM 3D Printer with Automatic Material System (AMS)

Bambu Labs X1 Carbon FDM 3D Printer

Fortus Large Format FDM 3D Printer

Prusa i3 MK3S FFF 3D printer

Raise 3D Pro 3 Hyper FFF

There's also an FLSUN printer if someone wants to make a page for it.

Important Concepts

Bridging

Part of the reason why supports are necessary is that the filament does not cool instantaneously as it leaves the nozzle. Despite that, if there is an anchor point at the start and end of a segment, the printer can bridge the gap without needing support material.

8 perimeters

Brims

Brims are used for objects that have small surface contact area with the print bed, particularly tall and thin objects. The brim is a single-layer area that connects to the bottom of the object that increases the surface contact area. It can usually be removed without tools, leaving very little surface scarring.

Infill

The vast majority 3D prints do not need to be completely solid. The printer prints one or more lines around the perimeter of the model, then fills in any remaining space with a pattern. There are various infill patterns available and can be made sparse or dense. Sparse infill produces a lighter, quicker, but weaker part. Dense infill produces a heavier, slower, and stronger part. Infill may also be used decoratively by removing the top and/or bottom layers of the print.

Suggested infill:

• Decorative/low-use parts 0-20%
• Medium-use parts: 21%-50%
• Heavy-duty parts: 51%+

Adding walls/perimeters or choosing a different print orientation can improve the strength of the part.

Layer Thickness

The printer works by drawing a cross-section of each layer, then stacking the layers on top of each other. Thinner layers results in smoother output (less stepping and visible layer lines), but takes longer to print.

Materials

Even more text

Pausing

You can stop part way through a print, and one day I will teach you how!

Print Speed

Print speed varies depending on the type of feature being printed, the properties of the material, and the type of printer. For instance, non print moves can be fast because no material is being deposited and the extruder is just lifting and moving to the next area. Bridges, on the other hand, are printed quite slowly to allow the filament to cool and not sag or stretch as the nozzle moves.

Most of the printers at North Forge are high-speed printers. When using the high-speed function of the printers, it is necessary to use filament that is specifically designed for high-speed printing.

Print Temperatures

Print temperatures (nozzle and bed) can affect how layers stick to each other, how the print sticks to the bed, and the overall appearance of the part (threads or bubbles on the part). Most filaments will come with suggested settings listed on the roll. All3DP https://all3dp.com/2/temp-tower-cura-tutorial/ has more information on how to calibrate the temperature of any given filament.

Raft

Some words so you know what we're talking about.

Retraction

More text

Seams

You might want to know about seams, but you won't find out until I populate this field.

Skirt

Talking about it.

Support Materials

At all times during the print, the extruded plastic must have a surface to land on. Sometimes a shape has an overhang, an area where the print layer protrudes into open space. Consider, for example, the following 3D cross shape. The printer will first draw several square layers one on top of the other. When it reaches the four “arms” that extend outwards, there is nothing for the plastic to rest on. The 3D printer simply squirts the plastic into the air, where it sags and warps:

Cross shape

In order to support the part, a support is used. Most machines will use breakaway support made of the same material as the rest of the print, but with small enough contact points that it may easily be removed. Some printers have two nozzles or a material switching system. The second nozzle or material switching system can be loaded with a secondary support material that dissolves in water or a light chemical bath. Using a soluble support material means that the supports can be removed without mechanical force on the part, making it well-suited for complex and fragile parts.

We will eventually write more about supports, like support painting and overhang angles.

Walls/Perimeters

The printer will first draw around the perimeter of the object, then draw the infill pattern. The printer can draw the outline more than once. Increasing the number of perimeters will tend to increase the overall strength of the part. The below image shows two perimeters: one inside (shown in yellow) and one outside (shown in orange). Increasing the number of perimeters to eight (one outside and seven inside) makes a thicker solid wall.

2 perimeters

8 perimeters

Most prints will only need 2-3 walls, but adding more can improve the strength of the part.

Z-gap

Keep on writing about it. Only applies to FLSUN, Prusa, maybe Raise3D? Someone help please.

Testing and Calibration

There are some tests that you can do to calibrate various aspects of your print for righteous results. It would be great if someone could start listing them!

Some pictures would be great here to illustrate what pausing can do for a print (text on signs without AMS, embedded hardware)