Turners cube

Designer: Learn FreeCADLearn FreeCAD
Dimension: 100 x 100 x 100 mm
Filament: PLA+
Temperature: 205 degrees
Layer height: 0.25 mm
Printing time: about 20 hours
Post processing: one hour


OpenSCAD,  Blender, FreeCAD

This was the first FreeCAD 3D model I printed.

I used FreeCAD 0.16 following the video tutorial.


I started experiencing limitation of OpenSCAD few months ago while I was modeling a hollow shell that has many holes. It’s a part of desktop light kit.

Source file

The rendering of OpenSCAD takes about three and half hours in my Devuan Linux, AMD FX-6100 processor, 8 Giga memory. It’s ridiculous poor performance.

I thought spending half day of work just to create a simple model is bad for the 3D studio business I gonna run soon. So I tried it on brand new Devuan workstation I built. The hardware specification is as below:
OS: Devuan 64 bit Linux
Processor: Intel Core i5, Skylake
Memory: 32G DDR4
Graphic card: Nvidia Quadro 4000

i5 system renders the model about two and half hours. OpenSCAD have not supported multithread or GPU yet.

Since then I’ve been testing various 3D modeling software: Blender, BRL-CAD, OpenJSCAD, FreeCAD. I quickly went through 2,000 pages of Blender Noobs to Pro, got familiar with Mesh modeling technique. I was able to create an organic model within few hours.

Source file

Blender can be used to create a mechanical part that requires exact dimension and shapes but it’s tedious process. I’ll use Blender for organic or artistic model.
I think CSG (Constructive Solid Geometry) is superior method over Mesh modeling.

I spent two days on BRL-CAD and removed it. The UI is outdated, building a model requires many steps, tiny size of user community and tutorial demands tough and long learning curve.

Yesterday I managed to create the bulb cap using FreeCAD after few hours of trial and errors.


Source file

My impression on FreeCAD is it’s functional, has potential to growth. I wouldn’t expect the same quality such as SolidWorks or Fusion 360 though.


FreeCAD is a 3D CAD/CAE parametric modeling application. It is primarily made for mechanical design, but also serves all other uses where you need to model 3D objects with precision and control over modeling history.

FreeCAD is still in the early stages of development, so, although it already offers you a large (and growing) list of features, much is still missing, specially comparing it to commercial solutions, and you might not find it developed enough yet for use in production environment. Still, there is a fast-growing community of enthusiastic users, and you can already find many examples of quality projects developed with FreeCAD.

Darkside of RepRap 3D Printer

RepRap 3D Printers use plastic parts as core components. It demands heavy maintenance compared to metal parts. To maintain good printing quality, the owner should replace the plastic parts that affect movement of hotend, frame alignment in reqular base.

A month ago I replaced old PLA idlers with PLA+ idlers after I found one cracked idler. 20170127_0040


This was the third or fourth time I encountered a fixable printing failure. The turners cube could’ve been finshed in one 20 hours session. Instead at 18 hours 32 minutes 37 seconds, 90% of printing job, the hotend spitting PLA+ filament in empty air with jerky movements.

I immediatly knew some parts broken. After I got up the next day, I moved Steel Fisher on the work table and inspected it throughly.

The carriage on X  tower had a crack, there was little pressure on leftside of linear bearing.  20170126_0022

I used ziptie to apply strong pressure on the linear bearing so that the bearing wouldn’t move. 20170126_0029There was crack on the carriage of Y tower. It was holding firmly the linear bearings at the moment. I secured it with bigger ziptie.  20170126_0028I will have to replace all plastic parts with ABS ones to install heated bed annd enclosure on Steel Fisher.

How to resolve a failed print that requires long hours?

I try to limit model size under few hours in one session. Because if the print fails, it sucks. I can manage to reprint the model. Will I reprint anonther tuners cube for two days? What if it’s a paid print that I need to deliver to a customer?   It became relevant since I seriously planned to do 3D printing business.  I have two reliable RepRap 3D printers now. I need at least two more 3D Printers and UPS unit.

The turners cube failed at 90.25 mm height. 20170126_0031

I cut Turners cube to 0.75 mm height in FreeCAD, created a STL file and printed it, which took about two hours.20170126_0012

I glued the two pieces with Locktight. Then I fused the edges using 20W soledring iron and PLA+ filament followed by some sanding.20170126_0032




About janpenguin

Email: k2.mountain [at] gmail [dot] com Every content on the blog is made by Free and Open Source Software in GNU/Linux.
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