X-axis - hotend clearance Hello members, I have an i3 clone printer, and I was wondering if the relatively big clearance between the bottom of the X-axis bridge and the tip of the hotend has any practical purpose. [attachment 89053 IMG_20170116_095708.jpg] I'm positive that the bridge itself could lower itself all the way to the hotbed, so if i'd fasten the whole extruder assembly to the bridge so that the hotend tip would be just a few mm below the level of the bottom of the bearing, then i'd earn 3-4 cm of extra Z printing space. See the below PS image. [attachment 89054 IMG_20170116_095708_mod.jpg] Any thoughts? Thanks. https://reprap.org/forum/read.php?406,739600,739600#msg-739600 Tue, 06 Oct 2026 20:45:12 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?406,739600,740737#msg-740737 Re: X-axis - hotend clearance https://reprap.org/forum/read.php?406,739600,740737#msg-740737
[attachment 89286 IMG_20170120_215128.jpg] [attachment 89288 IMG_20170120_222501.jpg]]]> mortee Prusa i3 and variants Fri, 20 Jan 2017 16:13:17 -0500 https://reprap.org/forum/read.php?406,739600,740599#msg-740599 Re: X-axis - hotend clearance https://reprap.org/forum/read.php?406,739600,740599#msg-740599
For that matter, the metal behind the part cooling fan does currently have a huge hole cut in it. But I'll actually get rid of it entirely, as well as the metal part currently holding the extruder motor itself, as it is folded forward at the bottom of the bearings. With the new configuration, I'll need a horizontal platform for the motor somewhere around the middle of the sheet screwed to the bearings, so that would be a separate L section aluminium, also screwed. And I'll print a new frame/nozzle piece for the part cooling fan, so that it wouldn't need the vertical metal sheet folded up in front of the motor.]]> mortee Prusa i3 and variants Fri, 20 Jan 2017 08:15:12 -0500 https://reprap.org/forum/read.php?406,739600,740596#msg-740596 Re: X-axis - hotend clearance https://reprap.org/forum/read.php?406,739600,740596#msg-740596 Your proposal should work. Note o_Lampe's point. Looks like plenty of clearance between the carriages at the end of the rails and the Z motor couplings.
Usually a good idea to clamp the wiring to the carriage (Pclip, tywrap etc) as the continuous flexing of the joints can cause failure. Might be possible to use one of the top bearing screws.
While you have it striped down. I suggest you take off the front cooling fan and cut a big hole in the metal behind it (I actually made a big slot). Refit the fan. This means you can remove the fan and see/access the extruder really easily.]]> MCcarman Prusa i3 and variants Fri, 20 Jan 2017 08:06:08 -0500 https://reprap.org/forum/read.php?406,739600,740517#msg-740517 Re: X-axis - hotend clearance https://reprap.org/forum/read.php?406,739600,740517#msg-740517 o_lampe Prusa i3 and variants Fri, 20 Jan 2017 02:35:59 -0500 https://reprap.org/forum/read.php?406,739600,740310#msg-740310 Re: X-axis - hotend clearance https://reprap.org/forum/read.php?406,739600,740310#msg-740310
[attachment 89200 IMG_20170119_160523.jpg]]]> mortee Prusa i3 and variants Thu, 19 Jan 2017 10:11:44 -0500 https://reprap.org/forum/read.php?406,739600,740307#msg-740307 Re: X-axis - hotend clearance https://reprap.org/forum/read.php?406,739600,740307#msg-740307 bearing's bottom and the level of the hot end's tip. I plan on moving the whole assembly (together with motor, heat barrier and hot end) up relative to the bearings/bridge. So the only change would be that the X-axis beams would be much closer to the top layer being printed.]]> mortee Prusa i3 and variants Thu, 19 Jan 2017 09:53:13 -0500 https://reprap.org/forum/read.php?406,739600,740285#msg-740285 Re: X-axis - hotend clearance https://reprap.org/forum/read.php?406,739600,740285#msg-740285
Try it and see. No big deal and you have a lot of space to gain.]]> tjnamtiw Prusa i3 and variants Thu, 19 Jan 2017 08:45:14 -0500 https://reprap.org/forum/read.php?406,739600,740276#msg-740276 Re: X-axis - hotend clearance https://reprap.org/forum/read.php?406,739600,740276#msg-740276
Most extruders jam up with they get hot as the fitment is to hot to high and thus soft, so it goes everywhere vs down the hole its meant to.]]> Dust Prusa i3 and variants Thu, 19 Jan 2017 07:57:39 -0500 https://reprap.org/forum/read.php?406,739600,740267#msg-740267 Re: X-axis - hotend clearance https://reprap.org/forum/read.php?406,739600,740267#msg-740267 MCcarman Prusa i3 and variants Thu, 19 Jan 2017 07:34:29 -0500 https://reprap.org/forum/read.php?406,739600,739996#msg-739996 Re: X-axis - hotend clearance https://reprap.org/forum/read.php?406,739600,739996#msg-739996
Quote
MCcarman
Yes its there to allow air to cool the heat break.

"It", as in what exactly?]]> mortee Prusa i3 and variants Wed, 18 Jan 2017 11:27:30 -0500 https://reprap.org/forum/read.php?406,739600,739935#msg-739935 Re: X-axis - hotend clearance https://reprap.org/forum/read.php?406,739600,739935#msg-739935 The heat break (threaded tube) has a small diameter so there is a very small cross section for the heat to pass through. And its long enough to allow the air to cool it before the remaining heat soaks into the extruder area. The heat sink at the extruder is also cooling the motor.
If you look at an E3D hot end it has fins on the heat break to aid cooling and can have a fan to increase airflow.]]> MCcarman Prusa i3 and variants Wed, 18 Jan 2017 07:38:13 -0500 https://reprap.org/forum/read.php?406,739600,739661#msg-739661 Re: X-axis - hotend clearance https://reprap.org/forum/read.php?406,739600,739661#msg-739661
The question however, whether the clearing serves a practical purpose, is still open.]]> mortee Prusa i3 and variants Tue, 17 Jan 2017 10:45:50 -0500 https://reprap.org/forum/read.php?406,739600,739658#msg-739658 Re: X-axis - hotend clearance https://reprap.org/forum/read.php?406,739600,739658#msg-739658
I'd be alarmed, when the heater block would be so close to the linear bearing. Maybe you can turn it around, so the heater element is in front of the nozzle?]]> o_lampe Prusa i3 and variants Tue, 17 Jan 2017 10:41:09 -0500 https://reprap.org/forum/read.php?406,739600,739600#msg-739600 X-axis - hotend clearance https://reprap.org/forum/read.php?406,739600,739600#msg-739600
I have an i3 clone printer, and I was wondering if the relatively big clearance between the bottom of the X-axis bridge and the tip of the hotend has any practical purpose.

[attachment 89053 IMG_20170116_095708.jpg]

I'm positive that the bridge itself could lower itself all the way to the hotbed, so if i'd fasten the whole extruder assembly to the bridge so that the hotend tip would be just a few mm below the level of the bottom of the bearing, then i'd earn 3-4 cm of extra Z printing space. See the below PS image.

[attachment 89054 IMG_20170116_095708_mod.jpg]

Any thoughts? Thanks.]]> mortee Prusa i3 and variants Tue, 17 Jan 2017 07:13:37 -0500