Thingiverse
Parameterized Angle Bracket by fluidhomefront
by Thingiverse
Last crawled date: 5 years, 5 months ago
Brackets for joining wood or extrusions at various angles. A variety of sizes and angles are provided.
The FreeCAD v0.19 file is included and the parameters are set from the embedded spreadsheet. Changing a number automatically updates the shape.
Use large washers to spread the force onto the plastic for maximum strength. Use a dense and isotropic infill, e.g. 50% cubic.
I printed using ABS / ASA with 0.5mm nozzle and 0.3mm layers. The ABS needs good bed levelling and a wide 10mm brim to hold it to the bed during thermal warping.
Very shallow angles (>135deg) may need supports.
Finite-Element-Analysis
The FreeCAD file works well as a test case for the FreeCAD v0.19 FEM_Module.
To prepare the analysis:
Make the screw holes a bit bigger to help the meshing, e.g. 5mm radius
Start the FEM module and click the "A" button to add an Analysis
Select the last LinearPattern element of the Part
Select Mesh => FEM mesh from shape by GMsh and hit "Apply"
Add a material with the yellow ball button and choose "ABS-Generic"
Scroll down to the bottom of the materials tab and select the "solid" radio, then click "Add" and click on the bracket in the 3D view.
Click Apply at the top of the material tab.
Add the boundary conditions by selecting the Analysis node then Model=>Mechanical Constraints=>Fixed Constraint on the vertical surface. Then add a force boundary condition to the other mounting surface.
Double click the SolverCxxTools node, "Write .inp file" and "Run CalculiX".
Once the results are converged, examine the maximum von Mises stress to see if it is less than the yield strength for your plastic, e.g. ~20MPa for ABS.
The FreeCAD v0.19 file is included and the parameters are set from the embedded spreadsheet. Changing a number automatically updates the shape.
Use large washers to spread the force onto the plastic for maximum strength. Use a dense and isotropic infill, e.g. 50% cubic.
I printed using ABS / ASA with 0.5mm nozzle and 0.3mm layers. The ABS needs good bed levelling and a wide 10mm brim to hold it to the bed during thermal warping.
Very shallow angles (>135deg) may need supports.
Finite-Element-Analysis
The FreeCAD file works well as a test case for the FreeCAD v0.19 FEM_Module.
To prepare the analysis:
Make the screw holes a bit bigger to help the meshing, e.g. 5mm radius
Start the FEM module and click the "A" button to add an Analysis
Select the last LinearPattern element of the Part
Select Mesh => FEM mesh from shape by GMsh and hit "Apply"
Add a material with the yellow ball button and choose "ABS-Generic"
Scroll down to the bottom of the materials tab and select the "solid" radio, then click "Add" and click on the bracket in the 3D view.
Click Apply at the top of the material tab.
Add the boundary conditions by selecting the Analysis node then Model=>Mechanical Constraints=>Fixed Constraint on the vertical surface. Then add a force boundary condition to the other mounting surface.
Double click the SolverCxxTools node, "Write .inp file" and "Run CalculiX".
Once the results are converged, examine the maximum von Mises stress to see if it is less than the yield strength for your plastic, e.g. ~20MPa for ABS.