MakerGeeks.com Mini Kossel Kit - Junk! January 19, 2015 01:45PM |
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Re: MakerGeeks.com Mini Kossel Kit - Junk! January 19, 2015 02:36PM |
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Re: MakerGeeks.com Mini Kossel Kit - Junk! January 20, 2015 04:11AM |
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Re: MakerGeeks.com Mini Kossel Kit - Junk! January 22, 2015 11:37PM |
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Re: MakerGeeks.com Mini Kossel Kit - Junk! January 23, 2015 03:22PM |
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Re: MakerGeeks.com Mini Kossel Kit - Junk! January 25, 2015 02:48AM |
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Re: MakerGeeks.com Mini Kossel Kit - Junk! January 25, 2015 03:44PM |
Registered: 10 years ago Posts: 10 |
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rogueqd
I'm looking at buying a Kossel as my first printer. I'd already decided not to buy from MakerGeeks afrer seeing the youtube video.
I found this site that looks good (looks dont count for much) and my emails have been responded to quickly and helpfully. Does anyone have any experience with them?
[builda3dprinter.eu]
Any other comments would be helpful too. I have some previous Arduino and multicopter building experience.
Re: MakerGeeks.com Mini Kossel Kit - Junk! January 25, 2015 04:28PM |
Registered: 9 years ago Posts: 5 |
Thanks Tristan. I like the way you've mounted the filament reel at the top did you design that yourself?Quote
Tris
I bought a set of printed parts, rails to wheels conversion kit and the extruder spur gear from builda3dprinter.eu early last year and everything I received from them was high quality:
[attachment 47881 KosselParts.jpg]
A photo of my printer is on their showcase page (Tristan's Kossel UK): [builda3dprinter.eu]
Re: MakerGeeks.com Mini Kossel Kit - Junk! January 25, 2015 04:59PM |
Registered: 10 years ago Posts: 10 |
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rogueqd
Thanks Tristan. I like the way you've mounted the filament reel at the top did you design that yourself?
After more research I'm wondering if an XL is the way to go. The creator of the Griffin printer said Kossels dont have enough rigidity and can wobble a bit at larger sizes meaning you have to print slower to maintain accuracy. Ardon from builda3dprinter.eu also mentioned they could be wobbly but said it didn't affect the prints. Have you noticed anything like that?
Re: MakerGeeks.com Mini Kossel Kit - Junk! January 25, 2015 06:46PM |
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Re: MakerGeeks.com Mini Kossel Kit - Junk! January 25, 2015 06:47PM |
Registered: 9 years ago Posts: 5 |
It's a nice use of the space. Do you think the mass of the filament spool helps prevent the wobble, or makes it worse?Quote
Tris
Yes, I designed the spool holder myself! I wanted to make use of the otherwise wasted space at the top. The design is a bit weak where it attaches through the lid but I designed it around some bearings I already had, i.e. cheap!
I have noticed the effects of "frame wobble", it mostly shows up when the extruder changes direction suddenly, like at a 90 degree corner. The result is a "ripple" on vertical walls after the direction change:
Re: MakerGeeks.com Mini Kossel Kit - Junk! January 25, 2015 07:00PM |
Registered: 10 years ago Posts: 10 |
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rogueqd
It's a nice use of the space. Do you think the mass of the filament spool helps prevent the wobble, or makes it worse?
It seems to me that twisting is where the frame is weakest. Do you think little struts from the top bar of the bottom section, near where the motor mounts meet the frame, would hold the uprights stiffer and stop it wobbling? I guess you could even make large triangles from the middle of each side as long as the rollers could still come down far enough.
Re: MakerGeeks.com Mini Kossel Kit - Junk! January 25, 2015 08:47PM |
Registered: 9 years ago Posts: 5 |
Ok, I get it. I'm not an engineer, but the resonant frequency will come from how springy the frame is, right?Quote
Tris
It may make it better OR worse, it's all about the resonant frequency of the frame vs how fast the effector is oscillating...
Corner braces would certainly improve rigidity. There's already a good design on Thingiverse for such a brace: [www.thingiverse.com]
Re: MakerGeeks.com Mini Kossel Kit - Junk! January 26, 2015 07:22PM |
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Re: MakerGeeks.com Mini Kossel Kit - Junk! January 27, 2015 02:11PM |
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Re: MakerGeeks.com Mini Kossel Kit - Junk! February 09, 2015 06:02PM |
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Re: MakerGeeks.com Mini Kossel Kit - Junk! February 11, 2015 11:54AM |
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Re: MakerGeeks.com Mini Kossel Kit - Junk! February 11, 2015 01:08PM |
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Re: MakerGeeks.com Mini Kossel Kit - Junk! February 12, 2015 06:45AM |
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Re: MakerGeeks.com Mini Kossel Kit - Junk! February 15, 2015 12:34AM |
Registered: 10 years ago Posts: 16 |
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rogueqd
I'm looking at buying a Kossel as my first printer. I'd already decided not to buy from MakerGeeks afrer seeing the youtube video.
I found this site that looks good (looks dont count for much) and my emails have been responded to quickly and helpfully. Does anyone have any experience with them?
[builda3dprinter.eu]
Any other comments would be helpful too. I have some previous Arduino and multicopter building experience.
Re: MakerGeeks.com Mini Kossel Kit - Junk! March 10, 2015 08:30PM |
Registered: 10 years ago Posts: 5 |
Re: MakerGeeks.com Mini Kossel Kit - Junk! March 11, 2015 08:56PM |
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Re: MakerGeeks.com Mini Kossel Kit - Junk! March 14, 2015 09:07AM |
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Re: MakerGeeks.com Mini Kossel Kit - Junk! May 17, 2015 11:34PM |
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Re: MakerGeeks.com Mini Kossel Kit - Junk! May 18, 2015 03:55AM |
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Re: MakerGeeks.com Mini Kossel Kit - Junk! May 18, 2015 07:42AM |
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Re: MakerGeeks.com Mini Kossel Kit - Junk! May 18, 2015 12:32PM |
Admin Registered: 17 years ago Posts: 7,881 |
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However, I don't see why 3mm would need any more force than 1.5mm, for the same extrusion rate and nozzle size.
Re: MakerGeeks.com Mini Kossel Kit - Junk! May 18, 2015 02:15PM |
Registered: 10 years ago Posts: 14,685 |
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nophead
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However, I don't see why 3mm would need any more force than 1.5mm, for the same extrusion rate and nozzle size.
To feed the same volume of plastic you need to feed it (3/1.75)^2 = ~ 3 times slower but it takes ~3 times the force because the same pressure acts over three times the area.
Re: MakerGeeks.com Mini Kossel Kit - Junk! May 18, 2015 05:25PM |
Registered: 10 years ago Posts: 280 |
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dc42
1. Towers not quite perpendicular to the bed. In my case, there was no slop in the corner pieces, but I wasn't careful to ensure that the vertical and horizontal extrusions were perpendicular when i assembled it. Also, I had to hammer the extrusions through the corner pieces (as described in the instructions), which peels off shavings of plastic, and this could lead to the holes ending up not quite straight even if they were initially. I tried loosening some of the screws, pushing the frame square, and tightening the screws again, but I wasn't able to improve on it much. The effect of non-perpendicular towers was that after doing the usual 4-factor calibration (i.e. endstops and delta radius), the nozzle height was wrong along radial lines midway between the towers. I solved it by implementing 7-factor autocalibration from a single set of probe points in the firmware. What the autocalibration actually does is to adjust the tower positions, which to a first approximation compensates for the leaning towers. The firmware I am using also supports orthogonal axis compensation, so I don't have to put up with leaning prints.
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dc42
When I rebuilt the machine to increase the printable diameter to 300mm, I printed new corners and took more care when assembling the frame. Despite this, the towers still lean slightly.
I am currently converting the machine to use 2020 extrusion because I want more printing height. As I am a perfectionist and would like to eliminate the lean, this time I am using metal corners from Robotdigg.
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dc42
2. Extruder grinding through the filament, resulting in loss of traction. This plagued me for a long time, but I solved it eventually by reducing the extruder motor current from 800mA to 500mA. The reason is that if the motor can't push the filament, e.g. because the nozzle is not hot enough, or too close to the bed, or over-extruding, then it's important that the motor skips steps in preference to grinding through the filament.
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dc42
With these fixed, my Kossel produces prints more reliably and more quickly than my Cartesian printer. It also takes up less desk space. So I definitely prefer Delta over Cartesian. I wouldn't run a delta on Arduino Mega/RAMPS/Marlin, because the processor lacks the performance to drive a delta easily and the firmware lacks the features I need, but it appears that a lot of of people do.
Thanks, but I'm going to stick with the 2020 design I currently have.Quote
dc42
I'd offer to send you my 1515 Kossel vertices, but as you are quoting prices in $, I'm guessing you are in the USA, and I am in the UK to the postage could get expensive.
Re: MakerGeeks.com Mini Kossel Kit - Junk! May 18, 2015 07:39PM |
Registered: 9 years ago Posts: 7 |