2. Ditched Draft Designs

It’s been twice I had to change the design philosophy of the 3D printer I’m designing. It’s going to be the third time so before all effort is lost, here are the three design iterations I went though.

Iterations 1 & 2


Both iteration 1 and 2 are mere design drafts I went through to determine whether they are mechanically sound or not.

Iteration 1:

Draft of how the final assembly would look like

The Y axis…

Print Bed Under-Carriage

Print bed was planned to be 200mm x 200mm, upgradable to 300mm x 300mm but was abandoned due to increase in demand for printing space.
Furthermore, design language was not sound. Ugly in a sense….

Iteration 2

A design planned to have a print bed of 400mm x 380mm having being inspired by the Cetus3D but scaled larger. This one was too abandoned due to unsound design.

Iteration 3

Initially I wanted a cantilevered 3D printer design while drafting the 2 Iterations above, but having to think about it, it is not feasible for my demanding requirements such as large print bed and stability. It is suitable for smaller size 3D printers when comes to cost effectiveness.
So I decided to go with the Mendel configuration with the print bed moving by the Y-axis (forward and backward), the extruder and hotend moving along the X-axis (sideways) and the whole of the X-axis moving along the Z-axis (upwards and downwards).
The mendel design configuration has the most widespread implementation due to it’s simplicity. A good example is the Prusa I3.

My inspiration came from a Reprap 3D printer forum OpenBuilds, where people submit and share their designs and creations of 3D printers and CNC machines made with OpenBuilds materials. One that caught my attention was the Maximus Evolution. Simple and aesthetically elegant. With my requirements at the time was to have a large print area of 800mm x 400mm, I set out to design my own based on the Maximus Evolution.

Enter Iteration 3

Bigger and better! Instead of using V-slot rails of linear motion, I decided to go with linear guides which are more precise.

That is one  large linear guide rail for the Y-axis  In the design, rail width of 35mm was chosen with the guide block being flanged. With a heavy printbed, I designed it to be driven by four nema 17 stepper motors. The part that held the stepper motors and drive pulleys together was designed to be machined out of aluminum block.

How it looks like underneath……

The bottom part of the print bed. Here shown is the Y-axis Guide Block, carriage and the heated bed assembly.

As for the extruder, I need somewhere to start before going to the “Awesome” materials such as Nylon or carbon-fiber reinforced materials. It’s difficult for me to design one from scratch for now. So I started off based on that of the Prusa I3 design. The only difference is how the extruder-hotend assembly is mounted in this case on the linear rail for the x-axis and how it’s driven.

Issues

Procurement Difficulties.

The Z-axis uses 4080 c beam. It is nowhere available in Singapore other than to buy it online. With that comes cost due to shipment.

Cost

Shipment costs kill. At one point while doing a “cost survey” in aliexpress for the aluminum extrusions I need, the net cost was around SGD 16.50 with shipping being approximately SGD 34.50.
Also what made this design costly is due to the number of linear guides that are to be used. A total of 6 guide rails along with 10 guide blocks made the design cost inefficient.

Conclusion


An alternative design is needed.

Figures


Figure 1: Prusa I3. www.prusaprinters.org/prusa-i3/
Figure 2: Maximus Evolution. http://openbuilds.org/builds/maximus-evolution-still-another-xl-3d-printer.2563/

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