My bed mods

Topics around mechanical design, controller and electronics. Mods & hacks welcome.
zemlin
Posts: 297
Joined: Sat Oct 21, 2017 2:02 pm

My bed mods

Postby zemlin » Tue Jan 16, 2018 1:42 am

The day I ordered my N2+ printer, I also ordered some 12x12 aluminum and PEI for a custom build platform. Imagine my surprise when I found the N2 bed was not 12 x 12! I had also ordered 12x12 buildtak and 12x12 Kapton sheets.

Making a custom-sized aluminum/PEI bed would be significantly more expensive proposition using the factory bed dimensions, so I decided to see how I could use the 12x12, and perhaps make some other minor improvements in the process. I understand the 13" bed allows the machine to print a full 12" with either nozzle (but not both). Losing 1" of build with the right barrel isn't a big deal to me.
After hmming and hawwing a bit, I came up with a set of goals:
- 12x12 build surface uninterrupted by the binder clips.
- Offset the build surface from the edges of the heated platform. I believe some offset would improve the heating around the edges of the bed. I haven't been able to validate this theory.
- Retain the ability to purge off the bed at the start of the print
- Adopt a 4-point spring-loaded bed leveling setup.

I found there was room at the front of the gantry for about 12mm of additional travel before hitting anything.
I made a switch mounting plate which shifts the y-axis switch 10mm to the front. You can find that here:
viewtopic.php?f=4&t=4791

The 4 outer corners of the HBP support screws are at 45 degrees. I measured and thought the set screw holes were 10x10mm, but that ended up being a little off. I don't know the correct number - but 10x10 was close enough to work. I believe the outer holes may be 30mm between centers, but don't assume that's correct. There was enough clearance in the holes that I did not have an issue.

I printed a drill guide that secured in the center of the corner holes with a flat head 3mm screw. I used this guide to drill 2 new 1/8" holes in the platform for leveling screws. The other two corners used exiting set screw holes. I shifted the heated platform 10x10 to the front and to the left.

I then printed tabs that attached to my 12x12 aluminum plate for the spring clips on the back and the binder clips up front.

Here are the springs, knurled nuts, and screws I used for my 4-point bed. Virtually no height lost with these wave springs. I dropped the bolt through the plate and secured it with an M3 hex nut.
wavespring.JPG
ThumbScrew.JPG
M3x25.JPG

I also printed some small washers to center the springs on the screws. Those STL files are attached. The washer with the large hole fits over the hex nut on the top plate. I'll get pictures when I'm back at home.
Attachments
bed-spring-washer2.stl
(62.97 KiB) Downloaded 11 times
bed-spring-washer.stl
(68.64 KiB) Downloaded 11 times

zemlin
Posts: 297
Joined: Sat Oct 21, 2017 2:02 pm

Re: My bed mods

Postby zemlin » Tue Jan 16, 2018 1:43 am

IMG_0593.jpg

IMG_0592.jpg

IMG_0591.jpg

IMG_0590.jpg

zemlin
Posts: 297
Joined: Sat Oct 21, 2017 2:02 pm

Re: My bed mods

Postby zemlin » Tue Jan 16, 2018 1:49 am

The bed clips on the aluminum were necessary for me to use the 12x12 MIC 6 I had. You can achieve the same benefit using the standard glass plate with your 12x12 surface of choice laminated - On my machines I offset from the front of the glass by 10mm and 7mm from the left.

I also made some thinner clips to use on a .25" sheet of garolite phenolic - but I have since moved to garolite on glass.

If you're interested, the clips, the drill guides and tap guides are attached on this and the next two messages. Note the thru holes on the aluminum - those prevent you from having to tap the 3mm holes blind in the aluminum. MUCH lower risk of breaking a tap in the plate.

On the drill jigs, the thick side goes on the top of the plate (before anything is laminated on top).
Attachments
bed-clip-25x16-drill-jig.stl
(94.81 KiB) Downloaded 14 times
bed-clip-25x16.stl
(165.22 KiB) Downloaded 12 times
bed-clip-10x26-drill-jig.stl
(57.7 KiB) Downloaded 13 times
bed-clip-10x26-tap-jig.stl
(72.15 KiB) Downloaded 12 times
bed-clip-10x26.stl
(145.49 KiB) Downloaded 12 times
Last edited by zemlin on Tue Jan 16, 2018 2:06 am, edited 2 times in total.

zemlin
Posts: 297
Joined: Sat Oct 21, 2017 2:02 pm

Re: My bed mods

Postby zemlin » Tue Jan 16, 2018 1:50 am

...
Attachments
bed-clip-25x16-tap-jig.stl
(65.12 KiB) Downloaded 11 times
bed-clip-25x16-250.stl
(172.64 KiB) Downloaded 9 times
bed-clip-10x26-tap-jig-250.stl
(72.15 KiB) Downloaded 10 times
bed-clip-10x26-drill-jig-250.stl
(57.7 KiB) Downloaded 10 times
bed-clip-10x26-250.stl
(146.47 KiB) Downloaded 9 times

zemlin
Posts: 297
Joined: Sat Oct 21, 2017 2:02 pm

Re: My bed mods

Postby zemlin » Tue Jan 16, 2018 2:01 am

...
Attachments
bed-clip-25x16-tap-jig-250.stl
(65.12 KiB) Downloaded 10 times
bed-clip-25x16-drill-jig-250.stl
(94.81 KiB) Downloaded 10 times

zemlin
Posts: 297
Joined: Sat Oct 21, 2017 2:02 pm

Re: My bed mods

Postby zemlin » Tue Jan 16, 2018 2:07 am

Questions, comments, critiques welcome.

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3DWP
Posts: 56
Joined: Fri Dec 15, 2017 5:48 pm

Re: My bed mods

Postby 3DWP » Wed Feb 14, 2018 1:52 pm

I have a question about this, I don't fully understand this bed. I am preparing a new bed (I have a second hand N2 Plus Dual) with Buildtak. The glass is now completey covered with Buildtak but my new sheets are 12x12 inches so smaller.

When I use the screen to move the head around I don't even get 300 mm in the y axis before it bumps the back.. And If i have to use the origin as beginning the nozzle will also hit the front clips if I want to use those (less than) 300 mm. I don't get it, am I missing something here? I thought the bed would have some offset on all sides.

So if I want to print almost 300 mm I have to my bed like this?
Last edited by 3DWP on Wed Feb 14, 2018 2:02 pm, edited 1 time in total.

zemlin
Posts: 297
Joined: Sat Oct 21, 2017 2:02 pm

Re: My bed mods

Postby zemlin » Wed Feb 14, 2018 1:59 pm

3DWP wrote:When I use the screen to move the head around I don't even get 300 mm in the y axis before it bumps the back.. And If i have to use the origin as beginning the nozzle will also hit the front clips if I want to use those (less than) 300 mm. I don't get it, am I missing something here? I thought the bed would have some offset on all sides.


That is exactly what I am addressing with this bed mod. As designed, the origin of the nozzle is off the bed on the front. That offset on the front is included in the total build area. Area occupied by the clips is also included in the build area. If you want to print a 300mm x 300mm square you're going to need to change how the bed is secured so the clips don't overlap the build area - which is what I've done here.

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3DWP
Posts: 56
Joined: Fri Dec 15, 2017 5:48 pm

Re: My bed mods

Postby 3DWP » Wed Feb 14, 2018 2:06 pm

zemlin wrote:
3DWP wrote:When I use the screen to move the head around I don't even get 300 mm in the y axis before it bumps the back.. And If i have to use the origin as beginning the nozzle will also hit the front clips if I want to use those (less than) 300 mm. I don't get it, am I missing something here? I thought the bed would have some offset on all sides.


That is exactly what I am addressing with this bed mod. As designed, the origin of the nozzle is off the bed on the front. That offset on the front is included in the total build area. Area occupied by the clips is also included in the build area. If you want to print a 300mm x 300mm square you're going to need to change how the bed is secured so the clips don't overlap the build area - which is what I've done here.


Well thanks for your mod and info but I feel a bit cheated by Raise3D then. Why all this room and don't account for those metal clips - and 297 is not 305 mm. Can you print 305 mm now?

zemlin
Posts: 297
Joined: Sat Oct 21, 2017 2:02 pm

Re: My bed mods

Postby zemlin » Wed Feb 14, 2018 2:22 pm

Bed clips in the build area is a pretty common practice on desktop 3D printers.
I need to run a modified firmware to reach the limits of the build surface since I've extended the Y-axis travel, but with that I have printed a 12" circle.

Jetguy
Posts: 2462
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: My bed mods

Postby Jetguy » Wed Feb 14, 2018 2:28 pm

320mm limit firmware for N2 Plus already done for you in this post viewtopic.php?f=4&t=4571&p=21220&hilit=320mm#p21220
Also, includes details in configuration.h if you decide to go custom .

Also, did N2 dual extruder to 320 in the same thread. viewtopic.php?f=4&t=4571&p=21220&hilit=320mm#p21223

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3DWP
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Joined: Fri Dec 15, 2017 5:48 pm

Re: My bed mods

Postby 3DWP » Wed Feb 14, 2018 3:14 pm

@zemlin: Yes I know, I was always frustrated with Up Plus bed clips so I made custom beds at the time. They required a raft. With the Raise I was happy using the Buildtak and I printed a few models raftless. But because the bed is so big I just assumed (never do that :oops: ) Raise3D would have offsets on all sides. Why else did they design it this big. I do see I could maybe move the homing switch a bit to hopefully get at least 300 mm Y.

@Jetguy: Thanks for the tip, I did not see that thread when looking for platform info on the forum. I'm no firmware hero but I can give it a shot, I already have this N2 pretty modded so more build volume (at least what is sold by Raise3D) would be great.


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