1 Topic by kallisti5

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Topic: Re-engineer SD2 bed

I've been having a lot of trouble with the SD2 bed.  I ran glass for a while on top, but now the heater has blown.
Given the odd arrangement of mounting screws on the bed, there are few options out there for replacement.

As my SD bed is warped.. I really don't want to sink any more money into the existing solution.

McMaster-Carr has a precision ground 6"x6" 1/4" plate of Aluminium for a great price:

http://www.mcmaster.com/#3511t11/=tend6o

I wonder if there would be some way to attach a full 6" heater pad to this chunk of aluminium and then somehow attach it all to the 3 mounting holes on the bed?

 
--  BED   ------------------------------------------------------
|                                                              |
 ---------                                             ---------
            |  Screw                           Screw   |
           +--                                       ---+

2 Reply by slimstar2

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Re: Re-engineer SD2 bed

I just got a new heater from Solidset on eBay 21.99 + shipping for my SD 3 maybe they have them for SD2 New 1 is much faster to heat up. covers full size of bed , is self sticking and draws 2x the power.

SD3, RAMPS 1.4, Lawsy's carriages modified by me, 2 SSRs, E3D V6, 2 Power supplies, Independent monitoring of both power supplies (amps and volts) also extruder and bed temps, Blue Tooth connectivity, bearings in all axis & rotational points, Y axis direct drive.  Remotely controlled power box on / off . Gecko Tec build plate . Renamed FrankenDoodle

3 Reply by Tin Falcon

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Re: Re-engineer SD2 bed

should be an easy upgrade. I have a solid doodle 4 so mine may be different .

You should be able to get a piece of  7075 aluminum from online metals for way less than Mcmaster cars price like $12 for 3/16 or $16 20 for 1/4"  .
the holes should be easy . drill them if you can drill hole through wood aluminum is not much harder then countersink the holes. as slimstar just suggested add a heat pad. 
Tin

Soliddoodle 4 stock w glass bed------Folger Tech Prusa 2020 upgraded to and titan /aero extruder mirror bed
FT5 with titan/ E3D Aero------MP mini select w glass bed
MP Utimate maker pro-W bondtech extruder
Marlin/Repetier Host/ Slic3r and Cura

4 Reply by kallisti5 (edited by kallisti5 2014-08-24 15:24:57)

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Re: Re-engineer SD2 bed

slimstar2 wrote:

I just got a new heater from Solidset on eBay 21.99 + shipping for my SD 3 maybe they have them for SD2 New 1 is much faster to heat up. covers full size of bed , is self sticking and draws 2x the power.

The issue is no-one sells heating pads for the SD2 with the hole pattern drilled, and you can't go drilling in those silicone pads...

http://www.soliforum.com/misc.php?actio … mp;preview

I looked into having custom heating pads made, but the up front cost was $500+.

Definitely thinking just replacing the whole damn thing is the way to go.. but i'd have to get creative with mounting given the hole pattern above to avoid drilling the QI-PD pad: http://store.quintessentialuniversalbui … product=36

5 Reply by wardjr

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Re: Re-engineer SD2 bed

You could just do as I did and put a thin piece of metal under the insulation to hold the pad and extra insulation to create some extra thermal mass.  Then use a heat pad that fits in between this three screws and don't worry about the holes.  The heat distribution to the edges of the build plate is more than adequate.

Printit Industries Model 8.10 fully enclosed CoreXY, Chamber heat
3-SD3's & a Workbench all fully enclosed, RH-Slic3r Win7pro, E3D V6, Volcano & Cyclops Hot End
SSR/500W AC Heated Glass Bed, Linear bearings on SS rods. Direct Drive Y-axis, BulldogXL
Thanks to all for your contributions

wardjr's Website

6 Reply by kallisti5

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Re: Re-engineer SD2 bed

hm.. actually I think I have a nice solution:

Two plates of Aluminum...

top: 7075 Aluminum   6.35"  x 6.00"
bottom:  some cheap Aluminum  6.35" x 6.00"

Hold both plates together via 4 standoff nuts and screws in the extra 5.mm on each side.
Drill the 3 mounting holes on the bottom plate, and stick the heater to the bottom of the top plate.

7 Reply by kallisti5 (edited by kallisti5 2014-08-24 18:02:22)

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Re: Re-engineer SD2 bed

(not a bad price on online metals as Tin Falcon said).. $20 after shipping for the top piece.  $11 for the cheaper bottom plate.

That plus a 6x6 $19 heated bed... I think we might have a winner.
http://store.quintessentialuniversalbui … product=36

8 Reply by kallisti5

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Re: Re-engineer SD2 bed

http://unixzen.com/patchwork/solidoodle2-bedreplacement.png

9 Reply by Tin Falcon

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Re: Re-engineer SD2 bed

Looks good but IMHO a piece of fiberglass mat in between will keep the bottom plate from cooling the system .

Tin

Soliddoodle 4 stock w glass bed------Folger Tech Prusa 2020 upgraded to and titan /aero extruder mirror bed
FT5 with titan/ E3D Aero------MP mini select w glass bed
MP Utimate maker pro-W bondtech extruder
Marlin/Repetier Host/ Slic3r and Cura

10 Reply by kallisti5 (edited by kallisti5 2014-08-24 21:40:49)

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Re: Re-engineer SD2 bed

Tin Falcon wrote:

Looks good but IMHO a piece of fiberglass mat in between will keep the bottom plate from cooling the system .

Tin

Hm.  Maybe Nylon stand offs?  The melting point of Nylon is 190 C (well above what the bed would be run at, although I wonder at which temperature nylon gets soft.)

Insulation was also a thought with this design, pretty easy to slip some glass matt between the top and bottom layers. The goal is an air gap between the top of the QU-BD pad and the bottom, but might as well do some fibreglass while i'm at it.

11 Reply by wardjr

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Re: Re-engineer SD2 bed

You'll want some layers of fiber glass for sure otherwise heat will definitely transfer down to the platform.  My heater is huge and this was the only way to prevent that from happening.  The sandwich really helps to distribute and even out the heat.

Printit Industries Model 8.10 fully enclosed CoreXY, Chamber heat
3-SD3's & a Workbench all fully enclosed, RH-Slic3r Win7pro, E3D V6, Volcano & Cyclops Hot End
SSR/500W AC Heated Glass Bed, Linear bearings on SS rods. Direct Drive Y-axis, BulldogXL
Thanks to all for your contributions

wardjr's Website

12 Reply by grob

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Re: Re-engineer SD2 bed

Looks like a good plan - the thicker the top plate the better, within mass/height/cost constraints to your liking!

My 2c:

* I would personally drill and tap the mounting points into the top plate, use a collar as a standoff and bolt it on from underneath, making sure the screws were 1mm or so short to leave the top surface flush for glass etc.

* Note that one of the functions of the spring-mounting is to allow for thermal expansion in the plate without causing warping. If you have a hot alu top plate rigidly bolted to a cold bottom one, it's possible the whole assembly will warp. Based on CTE for 7075 from here I'd calculate a distance movement between 185mm (guesstimated) centers of ~ 0.5mm (for 100C TD). With the plate distance from your diagram, assuming the two plates were perfectly 'bonded' (like a bimetallic strip; very much worst case!), looks like up to 1mm of height diff from bolt hole to plate center. In reality it would be much much less as it would just push around or bend the standoffs (much less stiff than the plates...): knowing they're going to move whatever you do, consider allowing for some slip in the lower plate mounting holes (e.g. ~0.5mm oversized bottom plate holes, nylon or fiber washers both sides of the bottom plate, loctite on the thread into the top plate and only tighten the bolts snug).

* Insulation in the sandwich will be handy for quick bed heating - adhesive auto stuff is fine. But note that any heat lost from the bottom of the bed just goes to heating your chamber (which is the best way to keep your warping down), so it's not really wasted - just the time!

SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi

13 Reply by kallisti5 (edited by kallisti5 2014-08-25 02:49:04)

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Re: Re-engineer SD2 bed

grob wrote:

Looks like a good plan - the thicker the top plate the better, within mass/height/cost constraints to your liking!

My 2c:

* I would personally drill and tap the mounting points into the top plate, use a collar as a standoff and bolt it on from underneath, making sure the screws were 1mm or so short to leave the top surface flush for glass etc.

Yeah, that was one side effect of the wider build plate... no dump area on the back right.  (and a potential screw head to interfere)

Tapping M3 (gotta be M3 tongue) half way into the top sheet may be a better option... worst case if I screw up the tap I can drill through.


grob wrote:

* Note that one of the functions of the spring-mounting is to allow for thermal expansion in the plate without causing warping. If you have a hot alu top plate rigidly bolted to a cold bottom one, it's possible the whole assembly will warp. Based on CTE for 7075 from here I'd calculate a distance movement between 185mm (guesstimated) centers of ~ 0.5mm (for 100C TD). With the plate distance from your diagram, assuming the two plates were perfectly 'bonded' (like a bimetallic strip; very much worst case!), looks like up to 1mm of height diff from bolt hole to plate center. In reality it would be much much less as it would just push around or bend the standoffs (much less stiff than the plates...): knowing they're going to move whatever you do, consider allowing for some slip in the lower plate mounting holes (e.g. ~0.5mm oversized bottom plate holes, nylon or fiber washers both sides of the bottom plate, loctite on the thread into the top plate and only tighten the bolts snug).

Great thought on the warp.  I was considering some screw tight holes to prevent wobble, but maybe replacing the stand offs with some bolts with springs? (that might prove too much wobble though) maybe I should rigidly fix the bottom plate to the Z-axis and then redo the spring system between the two plates.

14 Reply by grob (edited by grob 2014-08-25 04:07:01)

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Re: Re-engineer SD2 bed

kallisti5 wrote:

Tapping M3 (gotta be M3 tongue) half way into the top sheet may be a better option... worst case if I screw up the tap I can drill through.

Just drill and tap through, I assume you'd be glassing the top anyway, and the far corners are the least useful bit of the build area...


kallisti5 wrote:

I was considering some screw tight holes to prevent wobble, but maybe replacing the stand offs with some bolts with springs? (that might prove too much wobble though) maybe I should rigidly fix the bottom plate to the Z-axis and then redo the spring system between the two plates.

There is kind of a redundant layer here, I suppose.

If it was me, I'd keep doing exactly what you're doing, it's a tidy design: but make sure there was a tiny bit of slip in 3 out of 4 of the mounting holes to allow for expansion. The 4th one can clamp right down and prevent it from being knocked around more than absolutely necessary. I suggest the nylon washers as they'll slip a bit even when snug (i.e. tighten just to the point there's no axial movement in the joint), and the loctite/superglue in the thread will prevent a not-fully-tightened bolt from coming loose due to vibration.

There's wobble inherent in the cantilever design of the bed (it bends those 3/8" rods) as well as the bed springs, so introducing the possibility of a touch more is not a huge deal, and might just be a price of a warp-averse arrangement. I think you could easily arrange it such that the other wobbles were much easier to actuate than the slip allowed in the bolts in your bed sandwich, so you'd never see any adverse effects.

SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi

15 Reply by grob (edited by grob 2014-08-25 04:11:46)

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Re: Re-engineer SD2 bed

Also, here's some food for thought on leveling - technically, if we copy the vibration/wobble/fall-out-of-adjustment paranoia of the laser alignment community, given we have z-stop adjustment, we only need two adjustment screws to level a bed:
http://www.newport.com/Optical-Mirror-M … ntent.aspx

SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi

16 Reply by kallisti5 (edited by kallisti5 2014-08-30 22:17:40)

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Re: Re-engineer SD2 bed

whoo-hoo!

Things working out really well... under $50 and almost done!

Now I just need to find some good (heatsink?) tape to stick the heater to the bottom of the top plate.  Surface is a *lot* flatter than SD's stock bed... there is a slight bow but it is miles better.

Some pictures attached.  Used springs on the junction of the top and bottom bed to help with waping when heated.


http://www.soliforum.com/misc.php?action=pun_attachment&item=6146

http://www.soliforum.com/misc.php?action=pun_attachment&item=6147

http://www.soliforum.com/misc.php?action=pun_attachment&item=6148

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17 Reply by grob

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Re: Re-engineer SD2 bed

Nice! Good work with the springs on the bolts, that looks like it'll do just fine!

SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi

18 Reply by kallisti5

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Re: Re-engineer SD2 bed

Thanks!

Right now the M3 screws are going through 8mm stand-offs... I think that is a little more complex then it should be.  Going to replace the female-female standoff with a male-female and screw the standoff into the top plate. Surface is pretty flat and level... gonna have to turn the extended z-stop way out though :-)

19 Reply by kallisti5 (edited by kallisti5 2014-09-09 13:07:56)

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Re: Re-engineer SD2 bed

Whoo!  My heatsink tape finally came in... it doesn't seem to stick well to the rubber pad though. The tape works but I'm afraid to leave the pad "dangle" by it.  Some fiberglass will help hold it up though when I find some.

First test, 60C in ~60 seconds. Not bad!  Now I just want to beef up the traces on the printrboard for the 11.5 amp heater by scratching off the solder mask with a fibreglass pen and laying down some solder.  I also think I could of gotten away with 6 or 7 mm stand offs to help reduce my platform height... but that is my next project.  Another option may be using a build plate PCB that is 6x6 and screwing it to my bottom plate. (as it lets me use whatever mounts I want)

http://i.imgur.com/7oNs17C.jpg

20 Reply by kallisti5

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Re: Re-engineer SD2 bed

Frankendoodle is alive!!!

  • Replaced print bed with custom design

  • PET Tape

  • 12V 30A Power Supply

  • E3D Extruder

  • OctoPrint

  • PowerTail

https://vimeo.com/112308243


Never going to buy another Solidoodle, but she is a lot more useful now in making quality prints.