Ramblin' Dan's Workshop

The Sanctum of Fine Art and Invention

3D Printer Expectations

DSC07030Large scale diesel locomotive partsI have now had a bit of hands on experience with my low cost RepRap machine. So my comments are qualified preaching. Without experience, talk is just talk about imagination, and maybe repeating what others have said. Nothing replaces personal experience. It’s called practice what you preach. Good athletes and musicians do it all the time, practice. Ha! So don’t repeat what I say here, go and do it!

I come to 3D printing with a good background in very accurate 3D CNC subtractive machining. I routinely do superb 3D wax carving on my three CNC milling machines. I know what can be achieved with good machine design, programming and patience.

I deliberately entered into 3D printing at the low end. I had expectations of what I consider low quality, poorly detailed output. My machine does meet and even exceeds those expectations. Did I receive my money’s worth? Absolutely. I have a fully functional and very useful 3D FDM printer. I have many uses for it, but high quality carved wax detail finish straight off the machine is not going to happen. Look at the picture. They Look good but study the surface ripple detail. Very good but not great in my opinion.

The problem is my RepRap machine is designed like a printer and not a milling machine.

The print head is a major problem. There are two spinning fan motors, while seemingly well balanced do have some vibration and also generate gyroscopic precession forces against movement. What does the print head do… it moves A LOT. There is also a “coggy” stepper motor on the head to push the filament into the nozzle. More vibration source. Then the head is driven along rails with a belt that also picks up vibration. You see where this is going, a wobbly ride.

The “faults” are well known in the industry and other machine designs have tried to avoid them by putting the filament feeder somewhere off the print head, but then they have their own set of issues. So you pay your money and you make your choices.

The (required) bed leveling was rather shabby out of the box. It is a heated aluminum plate that will move a bit (warp) with heat. I could hear it “ticking” as it tried to move against restraint. That’s natural. I have improved the spring mounts a bit by drilling them out to allow for side movement except for height.

But that doesn’t make it a POS tool. I think I have an extremely useful and functional machine for what it CAN do. That’s make reasonable but not perfect plastic parts. I have said elsewhere that the solution for high quality is to use a print service when necessary. I don’t think for me that will be any time soon or often.

So my goal is not to “fix” this 3D machine in any major way. I will make minor improvements and keep up with maintenance, but my desire is to use it, not make a better mousetrap. I am very pleased with what I have because I fully understand and expected its inherent limitations. Sounds like a plan for satisfaction well executed.

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