Ahhh, yes the missing third wheel and I never noticed that. I have seen 3 or 4 but not 2 before so interesting.

How would you get the tension right? The third wheel is normally the eccentric so I am baffled at this.

 

What I was thinking so all wheels are actually eccentrics and no stationary wheels were used. As far as the mini wheels go I don't actually care for them and couldn't design them in as easily as the regular sized wheels.

 

Right idea but a horrible implementation by Prusa.

Look at the Tiko. For most of us that is a toy but it will have a great appeal due to how small, and self enclosed, it is. It is sort of cute and add a light to the inside (if it doesn't already have it) and you have the perfect "lady of the house" printer. Takes little knowledge with not much messing around, or tweaking, and away we go. I wouldn't touch it but for a child for school or for the lady of the house you bet your buttons it will sell.

Back to your printer now.

Having 2 in 2 (I feel like Chuck Woolery on the Love Connection, lol) is a really neat idea but I think it would be hard to get exactly right in your configuration. The 2 + 1 eccentric is dead sexy easy to get right though.

 

Disagree because the women I am talking about I have seen in focus groups who are not that tech savvy. We are not talking about the female geeks here we are talking about the LCD or the common woman. They like dainty cute things and from the two focus groups I was involved with that is precisely what they said they wanted. They were shown the picture of the Tiko and they loved it but I doubt the Tiko people have the money to advertise it to the non geeky women. That is what needs to be done is to take a printer like this and advertise it like it were Crayola Crayons on all the channels and it would blow the doors off of 3d printing.

This is where the Tiko, and there was one other I forgot what it was called now, fit that bill exactly.


Oh, and one thing will forever hold 3d printing back and can never ever be helped in FDM and that is how long it takes to print something. You can't tie up the kitchen table for 15-48 hours to make that really awesome print.

 

Just joining in here. I've been looking at CoreXY designs for weeks and this one has really caught my attention. On the previous page in this section there was mention of the AZSMZ board as possible choice for this machine. I'd definitely go that route. I've been using one in a custom Delta build that has been printing very well for the past 7+ months. Actually, I'm the person who designed that AZSMZ case on Thingiverse that was mentioned.

 

I don't have a 3d printer, so I'm also looking at designs that don't use a ton of special parts. I was looking at the D-Bot CoreXY and was quoted like $160 in plastic bits alone. So it made that cost restrictive.

Do you have a link to your build?

 

Please excuse my ignorance here, but...what makes the bed go up and down? I see a shaft with pulleys and 2 loops, but I don't see where they attach to the bed frame to move it? Is a BOM and other files still coming for this project?

Aside from the Z axis rod pulleys, it seems most of the green material can be had with OpenBuilds or other hardware brackets/motor mounts that those are the only "must be printed" pieces?


Also interested in your gantry design on the interior wheels only. Have you tested it? Is it still a good design?

I was thinking of buying openbuilds plates placing the wheels under it, as well as mounting the print head axis (X?) rail to the underside of the plate.

 

I do not and for some odd reason this forums no longer even notifies me of when messages are posted.

All of my work is in the toilet as I spent from 1am to 7:30pm trying to recover my HDD after Linux Mint did me in. I am very numb at losing 200 gigs of work but it is what it is and that is the problem with all of these huge drives is they would take me a lot of blu rays to backup on so I stopped backing up. I am going to get an external to back up my designs once I build the new PC with USB3.x on it.

 

Yep. See I used to be good about backing up but when drives got to be so big the dvd, then blu-ray, backups just were too small to handle so much data. I just checked and there are a lot of options but I am not sure which is the best with USB 3.x/UAS and will allow me to swap drives. If I want cheap WD has 1tb models for 60 dollars but you can't swap those out (I am leaning towards them but can't find any real reviews on them). I would just hook it up and unhook it from the back of the PC for backups so this doesn't happen again.

 

Keith, have you abandoned this design? You said it did not work well... could you elaborate on that?

Thanks

 

This design suffers from a very common coreXY layout error. The belt and pulley arrangement for the XY stage can't work the way it was done here.

In the top view of a stacked belt corexy mechanism diagrammed below, belt segments labeled A-H must all be parallel to their respective guide rails or the belt tension will vary as the extruder carriage is moved. The way the coreXY belts and pulleys were positioned in this design, a belt may become so loose the motor spins without moving the belt/carriage, or it could go the other way and the tension could get so high that the mechanism will bind and the carriage will stop moving. More details, here.




The other major problem with this design is that there is nothing to prevent the bed from crashing to the bottom of the Z axis if Z motor power is cut/lost. One solution to that problem is to use a worm gear drive reducer, but you must use high quality gears or you'll suffer repeating print defects in the Z axis with every complete turn of the worm gear.