A call for help/ideas to develop the Heated Bed

khiraly Wrote:
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> I should really create a summary blog about all
> this.


Here is an extensible writeup about this Dremel holder:
[blog.arcol.hu]

Best regards,
Laszlo

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Mendel build log: [blog.arcol.hu]

hey, decided to jump in. I also made a heated bed for my makerbot and it works well for abs. the key difference is that you only heat to 60 deg and print on plexi or lexan. I have been having some issues with getting too much sticking and still have to use a raft not because of warping but because my set up is not completely level yet. I did just order two of the mcmaster heaters and will see how those improve things, since my heater and platform are almost a 1/2" thick total it realy cuts into my z axis build area. Im hoping that with the mcmaster heaters i can try the straight aluminum table with kapton method.

I was also looking at nophead's work using the metal sheet held down by magnets and think this will be a great way to do unattended builds in the near future. Have a stack of build plates in a dispensor on the motor side of mendel and a set of offload rollers on the off side of the y table. when a build is done set up a mechanical arm that the x/z axis or extruder mount can push down and pop the metal sheet off the magnets or that moves a magnetic releasing shield over the magnets to release the plate and offload it onto the outfeed area (posibly using a simple hobby servo flipper attachment for the offloading).

still have to finish my mendel before i can get into building vitamins for a mendel i dont have though

What specific mcmaster parts did you order?

Makerbot now sells one heated bed. What do you think about their solution?

[blog.makerbot.com]

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New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]

Here is an extensible writeup about this Dremel holder:
[blog.arcol.hu]

Best regards,
Laszlo

Cool!

Want to mirror it on the wiki here?
[objects.reprap.org]

I am being trying to print a relative big piece, this one:
(link to thing).

It always do some warp, even with PLA and heated bed at > 60ºC. Today I had to abort because warp went very bad... and this time I just kept the room always closed, so none cold wind coming from open window.

Does anyone knows if maybe kapton tape can work just for one or to times and after and need to change for a new one? Or maybe I need to clean it first with alcohol?
Is anyone having this problems, warping with PLA even using heated bed?

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New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]

I haven't notice Kapton changing over time. I have printed a whole Mendel on the same piece, mainly ABS.

You could try blue masking tape instead for PLA. I think is sticks a bit better to that. The only downside is a matt finish on the base instead of shiny.

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[www.hydraraptor.blogspot.com]

nophead Wrote:
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> I haven't notice Kapton changing over time. I have
> printed a whole Mendel on the same piece, mainly
> ABS.
>
> You could try blue masking tape instead for PLA. I
> think is sticks a bit better to that. The only
> downside is a matt finish on the base instead of
> shiny.

Ok, thanks :-)

Just now I decided to buy for test this tape:
PET Heat Resistant/High Temperature Adhesive Tape (24MM*33M/-20~250-C)

The one I am using is this one:
Polyimide Heat Resistant/High Temperature Adhesive Tape (24MM*33M/260-C)

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New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]

Hmmm

You guys look to be having so much fun here I could'nt resist.

Thinking back to earlier threads on terazzo techniques and making machinery out of cast granite omponents.

Cross this with the floor tile idea, add in an embeded heating element (uninsulated nichrome)

Finaly use a plate of glass as the face of a mould.

And you get a granite/composite heating tile with embeded heating element. The face of which is perfectly smooth and flat (courtesy of the glass plate). Which can be made at home by anyone wihtout advanced machining techniques.

What it's performance would be like I have no idea. But it felt too sexy not to mention it.

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Necessity hopefully becomes the absentee parent of successfully invented children.

Oh forgot to mention.

Probably so obvious it is'nt worth mentioning. Insulate the sides and base of your hoeated beds to reduce the power consumption and make temp control more stable.

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Necessity hopefully becomes the absentee parent of successfully invented children.

Yes I was also thinking about using casting and glass to get a flat surface. To get even heat you need a pretty good conductor, or have it very thick. I was thinking along the lines of resin mixed with aluminium or copper powder to increase the conductivity. Or you need a diffuse heating element like a PCB with a zig-zag track.

Starts to look like the Makerbot solution!

We could embed thin magnets in the casting to hold a thin sheet of steel covered in Kapton.

BTW I have seen Neodymium magnets rated at only 80 or 90C. Not sure why as the Curie point in the wiki is much higher. They seem to work from me at 120C anyway.

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[www.hydraraptor.blogspot.com]

... when heated over 80°C the strong magnetized (over 1 Tesla) NdFeB-magnets start loosing magnetisation - not very fast, but noticeable ... and resin-based magnets even faster

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Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

nophead Wrote:
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> BTW I have seen Neodymium magnets rated at only 80
> or 90C. Not sure why as the Curie point in the
> wiki is much higher. They seem to work from me at
> 120C anyway.

YES, I noticed that too as I looked up sources for Neodymium magnets they all listed maximum operating temperature as 80°C and I know that you are running them between 100°C and 120°C.

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Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

aka47 Wrote:
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> Oh forgot to mention.
>
> Probably so obvious it is'nt worth mentioning.
> Insulate the sides and base of your hoeated beds
> to reduce the power consumption and make temp
> control more stable.

A foil interface between the bottom and the insulation might help reflect some of the heat back to the plate.

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B^2 : [replibot.blogspot.com]

~~ We Are The Factory ~~

Yup I have to agree about the magnets, Maybe Alnico will have a higher currie temp.

I had been musing about embeding magnetic strips, if only as a way to move towards a segemtned steel conveyor bed.

On casting conductive tiles. I was thinking along the lines of using Aluminium Oxide (Shot blasting grit, available by the bucket) as part of the agregate mix, and common portland cement as the matrix/binder rather than Epoxy or resin.

Aluminium oxide is a reasonalbly good conductor of heat but an insulator to low voltage electricity.

Once cured the heater tile/bad could be warmed gently to drive off excess water.

The down side to portland as a binder is the likely hood of it dusting off. I guess it would need a heat tollerant sealer once cured and dried.

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Necessity hopefully becomes the absentee parent of successfully invented children.

nophead Wrote:
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> Yes I was also thinking about using casting and
> glass to get a flat surface. To get even heat you
> need a pretty good conductor, or have it very
> thick. I was thinking along the lines of resin
> mixed with aluminium or copper powder to increase
> the conductivity. Or you need a diffuse heating
> element like a PCB with a zig-zag track.
>
> Starts to look like the Makerbot solution!

Makerbot solution is using acrylic, right? And they are going just to lower temperatures like 70ºC, right? (while we are going up to 120ºC).

We really need a flat surface if we do not want to use raft. Well, I think we can't use raft, If I remember some tries using it.

With a layer thickness of 0.35mm, we need to get a really flat surface if we want to have that 0.35mm on that layer... it's something that gives me work to get starting printing correctly.

Edited 1 time(s). Last edit at 02/26/2010 08:10PM by casainho.

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New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]

When I was designing motors for dental handpieces, I never used NdFeB magnets, because the heat from autoclaving the handpiece (~350 C) would destroy them. Instead, I used SmCo magnets, which are a bit more expensive because of the Cobalt, and slightly weaker than the NdFeB. But they had the benefits of withstanding very high temperatures, as well as being corrosion-resistant.

Alnico magnets are even more temperature-stable than SmCo magnets, and much cheaper. They're not quite as strong though, but probably extreme strength is not necessary (or a bigger magnet can be substituted).

I doubt that heated beds will ever need to go to autoclave temperatures, but I thought I'd share my experience anyway.

Edited 1 time(s). Last edit at 02/27/2010 12:30AM by jbayless.

casainho,
Yes for raftless printing it needs to be really flat, better than 0.1mm. when I made my mag bed I had to hand pick the nylon standoffs to get four the same length to within 0.1mm.

It seems to be hit and miss to get a flat piece of AL so it has to be machined, putting the cost up. I noticed The Ruttmeister used the lid of a die cast box, but die castings are renowned for warping so I think he must have got lucky.

Acrylic sheets are not that flat either in my experience.

I can only think of glass that comes perfectly flat but it seems to sit half way between a good insulator and a good conductor. We could glue a PCB on the top with silicone. The result should have a flat surface. We could put Kapton on top of that but then there is no way to release the objects, so back to tapping them off with a hammer.

We could put the heater underneath but then harder to control and still not way to release objects. I think glass would be too thick to use magnets underneath and steel on top.

Who would think it would be so hard to make something hot and flat?

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[www.hydraraptor.blogspot.com]

What about putting some kind of thin aluminum sheet on a glass backing, to even out the temperature? Meanwhile the glass plate could hold the aluminum flat.

Or vise versa; put a thin glass plate on top of an aluminum heat spreader.

nophead Wrote:
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> Acrylic sheets are not that flat either in my
> experience.

And acrylic at 120ºC for print ABS, will get very warpy!! I can't understand how it is used on Makerbot Heated Bed solution.


> Who would think it would be so hard to make
> something hot and flat?

Maybe we can do as extruder brass barrel and nozzle, ask for someone to do it with appropriated tools.

Or we can try to optimize for our DIY :-)


jbayless Wrote:
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> What about putting some kind of thin aluminum
> sheet on a glass backing, to even out the
> temperature? Meanwhile the glass plate could hold
> the aluminum flat.

I think that could work. A flat glass could work also as a bit of insulator. On top of the flat glass, we could put a thin sheet of aluminium, maybe a 1mm thick. That sheet could be glued to flat glass surface... and I believe it would keep flat with temperature changes over 25ºC <-> 130ºC.

How to hot the 1mm aluminium sheet? maybe with power resistors or nichrome wire, but at extremes side of the sheet, not on the center nor under it, instead on his top side where printed area did finish. Could this work? would the aluminium sheet get hot in the middle?

Under the glass we can put even a tile for get even more an insulator.

What you guys think?

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New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]

I have some 1/8" boro glass plates here so I did a quick test with 1/4" Neodymium cubes. It was no problem for two magnets to grip through the glass. And, one magnet was able to hold a steel nut through the glass pretty well. Using a strong magnet directly on glass may result in some shattered glass though...

Quote

And acrylic at 120ºC for print ABS, will get very warpy!! I can't understand how it is used on Makerbot Heated Bed solution.

It works in a slightly different way. The melting point of Acrylic is below the extrusion temperature of ABS so it will form a partial weld. That will be able to hold down a lot more force than the Kapton does, so you can use a lower temperature and still hold the ABS flat.

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[www.hydraraptor.blogspot.com]

Guys

I was not suggesting leaving the glass in place. Only using using the glass as the face component in the mold.

The cast piece then has a perfectly flat face because of the glass plate part in the mold.

Glass is a nightmare to heat things through. Lab Glassware is normally exceptionally thin. I have also had extreme problem cooking using other folks glass pans.

Thick glass the type used for glass pans is very prone to heat spotting.

Once the tile is molded, I guess we could stick the capton tape directly to perfectly flat face to minimise dusting off.

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Necessity hopefully becomes the absentee parent of successfully invented children.

hey i had a thought today about trying to use a ceramic floor tile for a heated printing bed, i would have to do some checking to see what ones would work better with a heater attached to it. but i think it would be a good idea. to try any how, or has any one else tried this idea.?

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[mike-mack.blogspot.com]

dissidence Wrote:
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> hey i had a thought today about trying to use a
> ceramic floor tile for a heated printing bed, i
> would have to do some checking to see what ones
> would work better with a heater attached to it.
> but i think it would be a good idea. to try any
> how, or has any one else tried this idea.?

Prusjar is using a floor tile on heated bed, but for insulate the heat. Is that what you want to do? -- remember that it should be a good temperature insulator.

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New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]

i was thinking about printing right onto the tile, with kampton tape on it.

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[mike-mack.blogspot.com]

dissidence Wrote:
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> i was thinking about printing right onto the tile,
> with kampton tape on it.

No, I think is bad idea to try get it hot. Since it is insulator, you wouldn't get a constant temperature all over it... and even be able to quick get it hot. Aluminium is the material for that, at last the best people did tried until now.

But the tile can be used for insulation of bottom of the bed, Prusjar did that and I believe is the best we can get for cheap DIY.

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New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]

A new Heated Bed kit is on selling, for Makerbot.

It's using a ceramic platform and kapton tape. And 60 or 70ºC...

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New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]

thats pretty much what i was thinking about doing right there, i guess i was far from the first person to think of this idea

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[mike-mack.blogspot.com]

dissidence Wrote:
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> thats pretty much what i was thinking about doing
> right there, i guess i was far from the first
> person to think of this idea

Yes, however I am curious at which temperature that bed goes, how much time takes and what power it uses.

I am happy to see at least 2 stores selling the Heated Bed! Is Heated Bed really important or are them trying to earn $$$ on having a new product?

Edited 1 time(s). Last edit at 02/28/2010 07:31PM by casainho.

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New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]