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Discussion in '3D printers' started by JCPhlux, Oct 22, 2015.
Discussion in '3D printers' started by JCPhlux, Oct 22, 2015.
Large Core XY 3d Printer W/fixed build plate
JCPhlux published a new build:
Read more about this build...
I will add real photos of the build this weekend. The build is about 95% done. just have to design one endstop and rewire it.
It looks great. I can't wait to see it.
I wonder how using 2 lead screws for the axis is going to work out. Could it rock front or back. Or even get jammed.
I'll be following this
It is very stable. With the XY gantry riding on 4 rails and 2 lead screws is is very strong. I have also placed the lead screw at the center of gravity of the gantry.
Once I finish up modeling the last few parts I will post of videos of it in action.
What made you go for a moving gantry as Z instead of the build plate? Wouldn't this require longer bowden tubes so it can move up and down with the gantry? And wiring seems a little more work too, since motors, end stops, extruder, etc. have to move up and down with it?
I love to see all the different builds on here. It helps to think about different options and their possible pros and cons while figuring out what I'd do for a build.
One of the greatest contributors to vibration a.k.a. ripple a.k.a. shadow a.k.a. ghosting is build plate movement. With a fixed plate you don't have that issue. All the movement is on the hot-end side so you don't get any ghosting.
Yes there is a bit more work but I think it is worth it.
Hm. I thought it's the relative movement between the hot end and the build plate. If the build plate is fixed, but the hot end vibrates with movement, don't you still get ghosting?
Ghosting all about movement of the printed object. If you look at an object with ghosting it is relative to the direction that the build plate moves. Your hot end if of good quality(E3D) will not affect this. it is all about the motion of the unsupported molten plastic.
Hm. I thought ghosting happens when there's unwanted movement between the place the plastic comes out and the place where it's supposed to go.
So if your build plate with the object is absolutely static, but the gantry itself (or the frame further up) starts to oscillate with too high acceleration values for example, you will still get ghosting, won't you? Or if the belt allows stretching / contracting on sudden movement changes.
Yes there is a chance of that but I think I have addressed most of that with my design.
The CoreXY is great for this with the belt being pulled and pushed(sorta) you don't get the slack in movement you would have in a traditional h-bot.
I have the CoreXY gantry mounted to the frame at 6 point giving it a very stable non oscillating build environment.
Most ghosting happens when the object is jerked around... think of it like a jello mold on a plate. Yes there is not that kind of crazy movement but you are dealing with molten plastic so there is some even if only for a few seconds, if it stayed molten for longer it would not be ghosting it would be blobbing.
There will always be quality issues the faster your movement settings are, with the current generation of 3d printer this is always going to be an issue. I get around this buy using good quality software to generate my g-code.
Re your point 4 - What software are you using?
I use Simplify3D. It is a bit pricey but I find it worth it. I have had print jobs that failed every time with slic3r come out flawless with it.
Wouldn't your firmware really control point number 4. I am excited to see how this comes out. I guess you got your jamming issues straightened out. I think that moving the gantry is definitely the way to go with large format printers. Ryan Carlyle has been tinkereing with a core xyz using 4 steppers and a mile of specra, he also built a delta out of a few square frames, one of which shares a name with yours.
What controller are you using?
That picture hurts my brain. It looks cool just not very functional.
Simplify3D will change the feed rates depending on the complexity.
Just a ramps 1.4 but I am using drv8825 drivers at 32 micro steps.
How is this coming along? I would love to see some pics. I am about to do a 200mm^3 bot for a buddy, this would be quite nice setup for it. I might add a leadscrew, I like odd numbers.
Waiting on a closed belt from china. I had to redesign the Z-Axis for 3 threaded rods as I was having issues with it staying level with fast movements. I will try to get some pictures posted this week as I am off all week.
Please see reprap wiki page Bateson for more on my use of Tesseract.
Let's see..upload image.
It makes a great filament case
I am working on a new design The new design is a complete redesign. The z axis was way too heavy. I will be setting up a new build for the new design soon.
(laughs), yes, it stores 24 reels nicely--you could put doors on it to protect the humidity.
Bateson is a cable drive right now with prospects of rapid wear but that's the way the degrees of freedom came out for self-replication: the motion axes had to be integrated into the frame.
Tesseracts are hugely stiff and light. How odd that they have *four* planes at mutual right angles. Like people say, do they come from another dimension? To build one the miter angle on that web is 33.6 degrees--you can get it with trig and square roots.
My landlord/GF got a miter saw to miter the floor molding the...quarter-round. I inherited it. I've set it to 33.5 degrees. Close as I could get. I figure if I get some round dowels, lay out 3 lines at 120 degrees, evenly spaced circles at one inch, I could screw one together in wood to get an idea of how they fit up, whether they frustrate themselves with impossible tolerances or not.
My first attempt at self-replicating milling machines was 1997. It was based on a drill press. My second just might be that machine updated, in a tesseract frame. You see, when you run the head up for large work, a drill press gets real floppy. A framed press gets stiffer. How neat. Julian Leland framed his self-replicating milling machine in a tetrahedral steel tube frame at Swarthmore.
I am really encouraged to see people running with the idea of the diagonals of the cube and the delta geometry and the alternatives to XYZ.
Why was your Z-axis too heavy?
Where are the photos?
I ditched this project. I don't have any video of it running but it was very loud and slow. I am working on a new machine based off what I learned from this one. Here is a picture of the design. I should have it build in the next month or so.
wait, was it the 8825 drivers? i keep hearing bad things
That was part of it. At its core it was an over engineered design. The new design is simplified and designed with accuracy and quietness first.