Preliminary research was carried out to see which open source designs and commercial 3D are popular in the 3D printer community. These will be used as a starting point for the development of the desktop 3D Printer.
Various repositories such as Youtube, Github, Instructables, GrabCad, Thingiverse, Personal Blogs and Technical Forums were searched.
Preliminary research was carried out to see which open source designs and commercial 3D are popular in the 3D printer community. These will be used as a starting point for the development of the desktop 3D Printer. Various repositories such as Youtube, Github, Instructables, GrabCad, Thingiverse, Personal Blogs and Technical Forums were searched.
## Popular Open Source/Kit 3D Printers
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@@ -153,30 +151,36 @@ Using **MoSCoW** method of prioritization to prioritize the design objectives.
## Current 3D Printer Design Log
### Frame
For the outer frame of the design, we start with the Hypercube Evoution design by thingyverse user Scott3D which has a boxed construction that has been tried and tested for rigidity and stiffness. The boxed frame is also easier to enclose which is necessary for printing ABS that requires a controlled temperature environment for good layer adhesion. The frame squareness after building can be verified by measuring the opposite diagonals. If they are the same you know have a square structure.
For the outer frame of the design, we start with the Hypercube Evoution design by thingyverse user Scott3D which has a boxed construction that has been tried and tested for rigidity and stiffness. The boxed frame is also easier to enclose which is necessary for printing ABS that requires a controlled temperature environment for good layer adhesion. The enclosed frame is also more importantly kids friendly. The frame squareness after building can be verified by measuring the opposite diagonals. If they are the same you know have a square structure.
### Mechanics
The design uses the CoreXY mechanism whereby the motors for the X and Y axis are fixed to the frame, which makes the X carriage that carries only the print head lighter than a conventional Cartesian design which has to carry the X axis motor. This should allow higher accelerations and printing speed.
### **CAD 3D Model**
Scott3D the original creator of the Hypercube Evolution design has uploaded a parametrized and configurable CAD file in Autodesk Inventor. This needs some modifications since the parameters don't work correctly in the original file. This is a good starting point but later designs will be carried out in Fusion 360. For now a build volume of 300cm3 will be used to build the first iteration.
Scott3D the original creator of the Hypercube Evolution design has uploaded a parametrized and configurable CAD file in Autodesk Inventor. This needs some modifications since the parameters don't work correctly in the original file. This is a good starting point but later designs will be carried out in Fusion 360 or Freecad. For now a build volume of 300cm3 will be used to build the first iteration.
Part of the design criteria is to fit the power supply and electronics under the base. This means the 3D printer is extended on the bottom by 100 mm but it has a clean look with increased safety by keeping electronics out of reach of (kids). Moreover, transport is easier and the printer can be easily placed on a desk. The printer size is increased on the top by 100mm to accomodate the moving cables of the print head during printing. The final frame size can be adjusted after the first prototype build, considering how space can be optimized within the printer.
Part of the design criteria is to fit the power supply and electronics under the base. This means the 3D printer is extended on the bottom by 50 mm but it has a clean look with increased safety by keeping electronics out of reach of (kids). Moreover, transport is easier and the printer can be easily placed on a desk. The printer size is increased on the top by 100mm to accomodate the moving cables of the print head during printing.
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### Linear Bearings Comparison
### Linear Bearings on Smooth rods Comparison
**Various Options for Linear Bearings on Smooth Rods**
1. Bronze bushing - Smooth bearings but could suffer from slip-stick effect if not properly aligned. Thez also need to be regularly lubricated.
2. Linear ball bearings LMXUU (with X for shaft diameter) - Less smoother than bronze bushings but also louder. Thez are more forgiving of misalignment. Thez are also less susceptible to wear.
According to this [Discussion](https://www.3d-druck-community.de/showthread.php?tid=11060) on difference between various linear bearings
1. Bronze bushing - Smooth bearings but could suffer from slip-stick effect if not properly aligned. They also need to be regularly lubricated.
2. Linear ball bearings LMXUU (with X for shaft diameter) - Less smoother than bronze bushings but also louder. They are more forgiving of misalignment. They are also less susceptible to wear.
3. Igus bearings (special polymer bushing) - similar to bronze bushings and are also susceptible to slip-stick effect.
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-[Discussion](https://www.3d-druck-community.de/showthread.php?tid=11060) on difference between various linear bearings
### Belts and Pulleys
Most commonly used belts in 3D printers are the GT2 belts which are toothed rubber belts which can have different reinforcing fibes such as steel, fibreglass or just rubber. The GT2 belt is usually 6mm in width and accordingly the pulleys used are GT2 pulleys. The size of the pulleys are specified by the inner bore diameter, the number of teeth and if the pulley is a smooth idler, toothed idler or toothed pulley to connect to a motor for instance. The various forms can be seen below.
### **Belts and Pulleys**
6mm wide rubber GT2 belts are used in the design. According to experience for users of CoreXY printers, here belts with steel reinforcement are to be avoided since these are not elastic enough and so can cause wobbling or misalignment of the idlers. Rather fibre reinforced rubber belts are to be used.
6mm wide rubber GT2 belts are used in the design. Here belts with steel reinforcement are to be avoided since these are not elastic enough and so can cause wobbling or misalignment of the idlers. Rather fibre reinforced rubber belts are to be used.
