Brick Roof Tile 4x2 45° inverted

I am always short of some bricks when creating LEGO MOCs (My Own Creation), so I am using FreeCAD and my printer to create temporary placeholders when prototyping.

This model is a brick compatible with LEGO's brick no. 4871 - ROOF TILE 4X2/45° INV. Essential piece for mech and (space)ship making.

The model was designed specifically for 3D printing with tolerances in mind.

For printing I recommend to start with attached FreeCAD project file and modify properties according to Printing Guide.

Printing Guide

(how to preserve compatibility with LEGO when printing)

There are several factors influencing compatibility with LEGO or other bricks system. Building capabality is mainly based on:

• friction, and
• spacing.

Friction is maintained by

• studs and tubes diameter,
• inner walls thickness, and
• auxiliary reinforcments.

Spacing is maintained by

• play tolerance offset.

With common 3D printer, we are not able to match required precision to create adequate friction, we can only approximate.

Basic printing parameters

• Material: PLA or ABS, PETG is not suitable because of worse bridging capability (problem mainly for plates).
• Layer Height: 0.15 or 0.2, both is OK.
• Perimeters: 3, print outside perimeters first.
• Infill: 15 % is OK.
• Supports: not needed, use brim if you have problem with adhesion

Model parameters

Relevant for this model. The model is quite hard to calibrate because it is using most of the available systems.

Play tolerance offset of 0,2 mm is a LEGO standard, there should not be a need to change that.

Beware: Parameters can also slightly differ with various materials, even different color from the same brand can influence the result.

What to do when

• Original LEGO brick does not hold on top of the printed brick (studs are too loose) - add to StudDiaMod in increments of 0,05 mm.
• Original LEGO brick cannot be placed on top of the printed brick (studs are too tight)  - substract from StudDiaMod in increments of 0,05 mm.
• The printed brick does not hold on top of original LEGO brick (walls are too loose) - add to WallThickMod in increments of 0,05 mm or to TubeDiaMod in increments of 0,05 mm.
• The printed brick cannot be placed on top of original LEGO brick (walls are too loose) - substract from WallThickMod or from TubeDiaMod in increments of 0,05 mm.

Share your printing settings and parameters for your printer. I will update the table. Exported files (3MF, STEP, STL) are with parameters for my MK4.

Other bricks

• Brick With Inside Bow 1x6x2 
• Parametric Tile with Groove
• Radiator Grille 1x2