Replacement Alu bed for those of us with no tools and/or time and/or confidence

My choice here when I get the new bed will be to continue with my present scheme but with the mdf replaced. I had already moved the spreader plate down onto the mdf as described in another thread on this topic. I haven't noticed any ill effects of the the heater being straight onto the glass without the spreader. I also use the 3 point sprung method already so the new bed will match that well. In my view doing this and eliminating the continuous z compensation is a major improvement in usability. With the new triangle bed I want to fix the nuts under the bed so the spring adjustment can be just be a top down twist of the screw from the top. I'll probably just abandon the current spreader altogether. I attach the glass and PCB just with some small picture clips cut and bent to to shape which push on fairly easily and secure it with not too much pressure.



With the triangular bed I'll have to rethink how the insulator is attached. I guess ideally it is best attached to underside of PCB in some fashion.

Indeed bobtidey, I'm pretty sure the heat spreader is redundant between the heater PCB and the glass - the spacing of the pcb tracks is much narrower than the thickness of the glass, so the temperature variation shouldn't be that great (if the tracks were say 10mm apart, then you'd get peaks and troughs that the aluminium would smooth out, but as it is it's fine). I tried one of my larger area prints after inverting the PCB and aluminium, and I got the same flat lower surface with no warping as I get with the normal configuration, so Erik's quick and dirty fix is a definite success for me. If the PCB is flat, clipping it to the glass should be ideal (as I said earlier, my RRP PCB is flat, unfortunately one I got from eBay wasn't and that bends the glass down when clipped - it shouldn't be an issue for stock Ormerod parts though), replacing the MDF which does very little in terms of supporting the bed levelling screws with something stiffer should give a huge improvement (as dc42, epninety and others have shown)

Ray

If It's not too late, I'd like one please.
PayPal is ok for me.

Pete

Sounds good, and yes I will keep this part running as long as needed, i can always get more cut in batches.

The bimetal thing i mentioned was because as per the book, the heater bed and spreader plate are bolted together in the corners, thus creating a fixed sandwich - ideal for bimetal warping.

As some have already removed the spreader plate, this may be a mute point though.

I will check my bed setup with a steel straight-edge when rebuilding it.

I also like the spring loaded idea, is this on all three points?

If the screws are long enough, a nyloc nut under the bed support would make adjustment easy, small spanner on the nut and just tighten or loosen the screw as needed, no other nuts would be used, the spring would keep the heater bed in contact with the spreader plate if used.

Edited 1 time(s). Last edit at 03/10/2014 04:12AM by Davek0974.

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Another RS Ormerod Mk1 meets the world

Retired now but I used to make....
CNC Machined Mk1 aluminium bed support plates for the Ormerod
CNC machined X-plates and ribs for Mk1 & Mk2 Ormerods
CNC machined bed support arms for the Mk2 Ormerod.
Dual Hot-End heatsink blocks.

I too would like if I haven't missed the boat and am happy with paypal.

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Davek0974
...I also like the spring loaded idea, is this on all three points?...

Not much point in springs at the two inner point as they only need to be adjusted once and I prefer two solid points to arrest the bed from any horizontal movement

I have one spring only at the outer corner

Disc springs might be a better option, might be easier to just ad disc to the hight needed instead of finding a normal spring at the correct length

Erik

Does the springs cause problems as the larger heavier 3D print completes?

How do you select to avoid compression or is this not an issue.

[edit] Also with the load on the single hole in the PCB heater is this a potential issue?

Edited 1 time(s). Last edit at 03/10/2014 06:10AM by Treth.

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Ormerod #007 (shaken but not stirred!)

I've placed the order, final price is £15 plus £3.00 uk p&p (1st class) each

This includes the mount holes drilled 3mm clearance and the rib holes countersunk plus 3 M3 x 20 socket head screws for the adjuster points.

Hope that's ok

Should be here in 4-5 days hopefully.


Dave

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Another RS Ormerod Mk1 meets the world

Retired now but I used to make....
CNC Machined Mk1 aluminium bed support plates for the Ormerod
CNC machined X-plates and ribs for Mk1 & Mk2 Ormerods
CNC machined bed support arms for the Mk2 Ormerod.
Dual Hot-End heatsink blocks.

I appreciate that it is probably too late for this batch as the order has already been sent, but please can I put my name down for one if you get another batch cut. Paypal is fine.

Thanks,

Ben

hello,

I would also like to put my name on the list for the next batch. paypal is fine.ik living in Netherlands. So shiping to Netherlands would be great.

Thanks, Ronald

Edited 1 time(s). Last edit at 03/10/2014 10:19AM by netcastle.

I did use 3 springs when I did this but more so it would be easier to tweak all 3 points if I found that necessary. I agree one could probably use 2 or 1. Ideally it would be nice to have the nut under the bed captured in some way so that tweaks canjust be from one end. Currently I need a spanner underneath. The other part to be careful about is there wasn't much clearance below on the back two so a nut is fine but the bolt can't protrude much.

I haven't seen any issues with sideways stability with springs but I haven't done any really heavy prints. I do use a nyloc nut at the top of the spring adjusted so that it just turns freely. The main reason was the conical part of the nyloc was a perfect fit into the end of the spring. Ideally I'd like to get some stiffer springs as I just used some from the Maplins kit and although they are Ok I think it would be better to use some with thicker wire and more stiffness. When I checked spring suppliers there are some good choices and the unit price is good but they tend to have minimum orders of around 15 UKP. Maybe another bulk buy? Disc springs might also be an option as suggested as one doesn't need much range.

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bobtidey
I did use 3 springs when I did this but more so it would be easier to tweak all 3 points if I found that necessary. I agree one could probably use 2 or 1. Ideally it would be nice to have the nut under the bed captured in some way so that tweaks canjust be from one end. Currently I need a spanner underneath. The other part to be careful about is there wasn't much clearance below on the back two so a nut is fine but the bolt can't protrude much.

How about tapping the 3 holes in the aluminium to take M3 bolts? You would probably want a nut on the other side as well to act as a locknut, but the adjustment would be from just one side.

Dave
(#106)

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dmould

Quote
bobtidey
I did use 3 springs when I did this but more so it would be easier to tweak all 3 points if I found that necessary. I agree one could probably use 2 or 1. Ideally it would be nice to have the nut under the bed captured in some way so that tweaks canjust be from one end. Currently I need a spanner underneath. The other part to be careful about is there wasn't much clearance below on the back two so a nut is fine but the bolt can't protrude much.

How about tapping the 3 holes in the aluminium to take M3 bolts? You would probably want a nut on the other side as well to act as a locknut, but the adjustment would be from just one side.

Dave
(#106)

It's an idea discussed earlier, it is possible but the strength of a fine m3 thread in aluminium is very poor and would strip easily. A nut on each side is far superior IMHO.

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Another RS Ormerod Mk1 meets the world

Retired now but I used to make....
CNC Machined Mk1 aluminium bed support plates for the Ormerod
CNC machined X-plates and ribs for Mk1 & Mk2 Ormerods
CNC machined bed support arms for the Mk2 Ormerod.
Dual Hot-End heatsink blocks.

IMHO an M3 thread in 3mm Ali will be fine, but a nut is probably better.

A properly pressed in steel nutsert would be better still.

My bed is 3mm Tufnol and uses springs on all three mounting screws, which are just tapped into the bed. You don't need massive spring rates unless you are going to use a half kilo of PLA on every print.
Also if your bed is stable, you won't be adjusting it as often as you are used to!

Dave

Quote
epninety
IMHO an M3 thread in 3mm Ali will be fine, but a nut is probably better.

A properly pressed in steel nutsert would be better still.

My bed is 3mm Tufnol and uses springs on all three mounting screws, which are just tapped into the bed. You don't need massive spring rates unless you are going to use a half kilo of PLA on every print.
Also if your bed is stable, you won't be adjusting it as often as you are used to!

Dave

The offer of tapped holes instead if clearance is still there, just need to know, I can ask when I contact buyers for details what options is preferred I guess.

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Another RS Ormerod Mk1 meets the world

Retired now but I used to make....
CNC Machined Mk1 aluminium bed support plates for the Ormerod
CNC machined X-plates and ribs for Mk1 & Mk2 Ormerods
CNC machined bed support arms for the Mk2 Ormerod.
Dual Hot-End heatsink blocks.

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Davek0974
It's an idea discussed earlier, it is possible but the strength of a fine m3 thread in aluminium is very poor and would strip easily. A nut on each side is far superior IMHO.

I agree, I really cannot see any advantage of treads in the thin aluminium - screws in treads will not be stable and will have to be supported by at least one nut, but the pull from one nut will slowly degrade the treads in the aluminium and it will move the adjustment when you tighten that nut, so the right thing will be to put nuts on both sides, but then you will have to tighten those two nut synchronously as not to destroy the treads in the aluminium or move the adjustment

Erik

How about rivnuts/nutserts?

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KP
How about rivnuts/nutserts?

Would have to add a fair amount of metal around the insert points, I think the two-nut option is the best and most practical one.

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Another RS Ormerod Mk1 meets the world

Retired now but I used to make....
CNC Machined Mk1 aluminium bed support plates for the Ormerod
CNC machined X-plates and ribs for Mk1 & Mk2 Ormerods
CNC machined bed support arms for the Mk2 Ormerod.
Dual Hot-End heatsink blocks.

I was thinking to use a fiberglass instead of alluminium, in this way all the heat from pcb heater will not spread via alu that is a good cooler...
I found a 3mm fr4 fiberglass that I think should give the correct support to the bed.
Do you think it's a good way?

It might work but fibreglass sheet is not too temperature stable either, it could still warp or bow when warmed up.

The alu bed does not get much heat from the heater bed, there is an air gap as well as the corrugated sheet in there.

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Another RS Ormerod Mk1 meets the world

Retired now but I used to make....
CNC Machined Mk1 aluminium bed support plates for the Ormerod
CNC machined X-plates and ribs for Mk1 & Mk2 Ormerods
CNC machined bed support arms for the Mk2 Ormerod.
Dual Hot-End heatsink blocks.

FR-4 is a fair match for Aluminium in thermal expansion, so not much to be gained on that score.

It won't (or shouldn't) warp or bow unless restrained (e.g. pcb traces can form the equivalent of a bimetallic strip)

3mm SRBP based Tufnol is working fine for me, but I'm not claiming any particular advantage over Alu.

Dave

Assuming bendability (or lack of it) is one of the major selection criteria then Young's modulus of the material should be the significant factor as the amount of bend for a particular force is inversely linear against the modulus ( Table). MDF as in the supplied design has a typical modulus of 4 GPa in the same region as many 'rigid' plastics. Tufnol depending on grade is significantly better ( 8 - 18 GPa). Aluminium and glass are much stiffer again, both being around 70GPa. At that level a 3mm sheet needs a significant load to bend by a factor that would influence the print. Carbon Fibre reinforced sheet would be great if it was affordable.So overall I think the 3mm new Aluminium triangle is going to be a good choice.

Edited 1 time(s). Last edit at 03/12/2014 02:30PM by bobtidey.

Quote
bobtidey
Assuming bendability (or lack of it) is one of the major selection criteria then Young's modulus of the material should be the significant factor as the amount of bend for a particular force is inversely linear against the modulus ( Table). MDF as in the supplied design has a typical modulus of 4 GPa in the same region as many 'rigid' plastics. Tufnol depending on grade is significantly better ( 8 - 18 GPa). Aluminium and glass are much stiffer again, both being around 70GPa. At that level a 3mm sheet needs a significant load to bend by a factor that would influence the print. Carbon Fibre reinforced sheet would be great if it was affordable.So overall I think the 3mm new Aluminium triangle is going to be a good choice.

Excellent, nothing like some figures to back things up

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Another RS Ormerod Mk1 meets the world

Retired now but I used to make....
CNC Machined Mk1 aluminium bed support plates for the Ormerod
CNC machined X-plates and ribs for Mk1 & Mk2 Ormerods
CNC machined bed support arms for the Mk2 Ormerod.
Dual Hot-End heatsink blocks.

Quote
bobtidey
Assuming bendability (or lack of it) is one of the major selection criteria then Young's modulus of the material should be the significant factor as the amount of bend for a particular force is inversely linear against the modulus ( Table). MDF as in the supplied design has a typical modulus of 4 GPa in the same region as many 'rigid' plastics. Tufnol depending on grade is significantly better ( 8 - 18 GPa). Aluminium and glass are much stiffer again, both being around 70GPa. At that level a 3mm sheet needs a significant load to bend by a factor that would influence the print. Carbon Fibre reinforced sheet would be great if it was affordable.So overall I think the 3mm new Aluminium triangle is going to be a good choice.

So it appears that the most stable material to use would be diamond. I'll see what I can find on eBay.

Dave
(#106)

New beds should be ready for despatch Tuesday hopefully

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Another RS Ormerod Mk1 meets the world

Retired now but I used to make....
CNC Machined Mk1 aluminium bed support plates for the Ormerod
CNC machined X-plates and ribs for Mk1 & Mk2 Ormerods
CNC machined bed support arms for the Mk2 Ormerod.
Dual Hot-End heatsink blocks.

Great stuff. Let us know the Paypal payment procedure you want.

I would be interested in buying one, paypal is good for me

Dave

Hello

Write me down for an bed too, cant wait to shoot the weak MDF out of ma Baby

EDIT: I have Paypal too

Edited 1 time(s). Last edit at 03/16/2014 05:20AM by Blitza.

Hi There,

I'd like to get one of these please if you have any left or add my name to the next batch. PayPal is fine with me. Thanks for the great work! :-)

Mark