Build Plate Adhesion, Support Material & Overhangs

Build Plate Adhesion

In slicing software, build plate adhesion refers to a structure printed on the base of a model to improve a model's ability to “stick" to the build plate while printing.

Poor build plate adhesion can result in prints lifting off the build plate and potentially damage the printer.

It is best to keep the model within 80% of the build plate as models that extend to the edges of the build plate could potentially lift and result in a deformed print.

Raft

A raft is a series of foundational layers printed before the main model. Typically rafts are comprised of a number of grid layers and a roof, creating a surface to which the main model can easily adhere.

Rafts are used to reduce warping and achieve better bed adhesion. They can also be used to stabilize models with small footprints or to create a strong area on which to build the upper layers of a print

Any build plate scratches, markings or perforations will transfer to the initial layer of a print. If you would like to avoid any build plate artefacts, you can use a raft.

Skirt

A skirt is an outline that surrounds a 3D model but does not touch the part.

Skirts are extruded on the print bed before starting to print the main model. They are usually used to check the printer's condition, slicer settings and to prime the nozzle.

If a skirt is not extruded correctly, it may be due to one of the following reasons;

• the print bed is not level

• hot-end or feeder is jammed

• there is no filament loaded/remaining on the spool

• under extrusion due to slicer settings.

Brim

A brim is a special type of skirt that is in contact with the edges of your model. Typically, the brim is printed with an increased number of outlines to create a large ring around the 3D model. They are often used to hold down the edges of a 3D model to help with adhesion and prevent warping or lifting.

dFab recommends using a brim for most prints.

Overhangs

An overhang occurs when part of a model’s geometry on a newly printed layer is no longer fully supported by the layer below. Generally, if an overhang exceeds 45 degrees, support will be required to successfully print the part.

If a model features a bridge (horizontal span between two walls) less than 10mm across, support material is often not required. This is known as bridging. Spans greater than 10mm should be supported. Excessive horizontal spans left without support material will result in material sagging

Support

Supports are additional, low-density structures generated by slicing software to assist in the printing of an object with overhangs.