Old guy wanting to learn..........

Question

Hello

I'll try and be brief. Simple questions from an old newbie who is bound and determined to build a 3D printer before I croak...........

The main reason I haven't purchased a 3D printer is because I haven't felt the working envelope was big enough for me to justify the price.

Question 1:

I am not seeing any reason that one cannot build a printer that has a considerably bigger working envelope. If there is no reason not to, then I am going to do that...........Any reason I can't do that? (somewhere around 36" in X, 15" in Y and 12" in Z)

Question 2:

My limited CNC experience utilizes a conventional computer to interface with the machine.............I'm told that 3D printers don't need that and that files can be loaded directly from a flash drive etc. So, I am unclear how the printer orients itself to a suitable position to begin the print. On a CNC machine we have to home the axes and designate a starting position (00) So how do it know? From all the videos I have seen the printers don't utilize monitors and keypads.

As you all can clearly see, I haven't a clue. The learning curve will be steep but I must start somewhere! Thanks for taking the time to read this.

danielw · Answer

I'm not so old but am part way through a printer build with a sturdy aluminium frame, and I'm hoping to re-use some reclaimed parts. Most of the FDM printers are either DIY or some project / commercial printers are similar to or based on the REPRAP project as mine will be. A quick google will get you a lot of information. Almost too much! I also looked at a lot of the posts by Rich Rap and also you tube videos of which a lot were by Thomas Sanladerer -- https://www.youtube.com/user/ThomasSanladerer I personally am going to use a Ramps 1.4 board with motor drivers which connects to an Arduino for the processor, I have a display that connects to rhe Ramps board which has a slot for a memory card. G code files can be saved to a card and put into the printer, or you can send the commands from software like Repetier Host (Other software is available) to the printer directly and no memory card is required. One thing I have seen is that some people have stability and print quality issues with communications from the PC, I believe due to bottlenecks in the data comms causing pauses so some people recommend using the memory card. There are limit switches for homing and can be used to set home positions and also detect over travel, stopping the printer if it tries to exceed the maximum travel. You can chose, mechanical, optical, or hall effect. The homing sequence is built into the firmware that is downloaded into the arduino board that controls the Ramps board. My printer will not be massive, about A4 build size. As the printers get bigger I think having the parts lift up of the build base could become an issue. We have a Robox at work and on a large-ish part we sometimes get lifting at the edges which are down to material shrinkage. This is with PLA which is supposed to be the less shrink-y plastic compared to ABS. I plan to enclose my printer to try and overcome the seasonal temperature changes, and dust that will be present in my garage. It should also help with lifting of the part from the build plate, I hope! If you want to see some of the large 3D FDM printers check out bigrep.com, re:3D | Large Scale Affordable 3D Printing , or just google large 3d printer.

Workshopshed · Answer

Q1: Big printers do exist so it can be done. You could lookup Kevin Caron on YouTube he's been using a massive delta printer to print things about 4ft tall. The issues could be heat / warping, print time and making it solid enough to not wobble and light enough to be fast.

Q2: 3D printers move some of the tasks that normally happen in CNC on the PC onto the printer. It's the equivalent of a motion controller in CNC. That allows you to squirt the GCode over to the printer and have it do it's stuff.

They typically self home by having a limit switch at one end of the axis or in some cases by touching the head on the bed and checking for that with a sensor.

Old guy wanting to learn..........

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