400mm round heatbed

Hi,

I'm looking for a 400mm round heatbed (400mm borosilicate glass, heatspreader and heater).
I know Ultibot has them but I'm looking for a suplier in Europe.
any ideas?
Thanks.

Walfried

First, you do not need to use borosilicate glass. Save some money by using ordinary 4mm float glass cut to size by your local glass merchant.

I am currently building a 330mm heated bed to upgrade my Mini Kossel. I bought a circular aluminium sheet on ebay here [www.ebay.co.uk] and I have a mains-voltage silicone heater coming from here [alirubber.en.alibaba.com]. This company will make a custom silicone heater to your choice of size, voltage and power, with the option of a 100K thermistor built in. To control the heater I am using a SSR-10DA.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

SAFETY WARNING
Normal glass expands and contracts much more than borosilicate glass, that causes internal stresses and specially on a 400mm diameter piece, is likely to quickly result in a shattered piece of glass, with all the safety concerns that brings.

Edited 1 time(s). Last edit at 03/22/2015 03:02PM by AndrewBCN.

@dc42
The seller on ebay for the aluminium would be perfect but doesn't ship outside UK.
As for the silicon heater I send him an e-mail.
Thanks

Quote
AndrewBCN
Normal glass expands and contracts much more than borosilicate glass, that causes internal stresses and specially on a 400mm diameter piece, is likely to quickly result in a shattered piece of glass, with all the safety concerns that brings.

Unless you have evidence to back up that claim, I cannot agree.

First, float glass doesn't shatter, it cracks. Perhaps you are thinking of tempered glass? From a safety perspective, I think a greater risk is shards of glass being removed from the bed due to excessively good adhesion to the print. This has been observed using both ordinarty float glass and borosilicate glass.

Second, the difference in coefficient of expansion between the glass and the aluminium bed that it is clamped to is greater for aluminium/borosilicate glass than it is for aluminium/float glass. Therefore, there will actually be more stress if borosilicate glass is used.

The advantage of borosilicate glass is that it is less likely to crack if subjected to high thermal stress. For example, if you heat the bed to 100C for ABS printing and then spill water on it, ordinary float glass will probably crack, and borosilicate glass may not. But this has nothing to do with bed size. There are many people printing ABS successfully on float glass, and as long as the bed heating is uniform (e.g. it has an aluminium heating plate to spread the heat well and an appropriately-size heater), borosilicate glass is unnecessary. But pay the extra and use it if it makes you feel better!

If you can get a sufficiently flat piece of aluminium, you could dispense with the glass, cover the aluminium with BuildTak, ABS juice, PVA glue or similar, and print on that.

Edited 1 time(s). Last edit at 03/22/2015 02:41PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

FWIW I have been printing on ordinary 3mm glass on a variety of machines for the past 12 months. As long as the glass isn't constrained around the edges so that it can expand and contract naturally it's absolutely fine. Our heat sources heat fairly gradually, even my current 1000W mains powered heater takes a minute or so to get to temperature. My glass takes a further 5 minutes to match the temperature recorded by the built in pad thermistor (according to the IR thermometer I use). I use a piece of 1.5mm thick aluminium as my heat spreader. The bed is 400 x 400. I've just finished my 4th 1Kg roll of filament. No issues with the glass. For potential cracks I always cover the entire bed with kapton tape. This would ensure no loose peices should the worst happen.

Ordinary float glass works OK for me.

I find it quite incredible that the OP posted that he was looking for a source of borosilicate glass, which is much safer than normal float glass for the specific use in FDM printers, yet dc42, AndyCart and hercek are going to the trouble of posting that normal float glass "works for them". You guys sure have a lot of spare time to post your opinions about the less safe alternative...

To each his own and I honestly couldn't care less about what you have been using and/or what works for you, but to suggest or advice that the OP should be using float glass instead of borosilicate glass just to save a few euros is totally irresponsible and plain dumb.

Now, since this is off-topic and I hate wasting my time, I invite you to post your opinions about the use of float glass as an ideal surface for FDM printing in the Safety subforum, where this issue can be debated at length...

Andrew, if you have any evidence that the use of float glass on a 3D printer poses a significant risk, pleaae share it. I have yet to hear of anyone experiencing a glass bed breaking, let alone in a manner that resulted in injury to anyone. Until I do, I will go on believing that my float glass printer beds are unlikely to break if I treat them sensibly, and in the unlikely event that one does break, I will not be stupid enough to cut myself on the sharp edges while disposing of it.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

And there I was thinking forums were all about sharing experience and opinions with others

Quote
AndyCart
And there I was thinking forums were all about sharing experience and opinions with others

I do wish there was a Like/Dislike button on this forum.

Well said Andy

Edited 1 time(s). Last edit at 03/23/2015 04:28AM by dougal1957.

Hi all
actually I am printing my new designed printer (TRUSS) with 550 mm actual bed print size
when searching I found this, and planning to order
its not in Europe as well but...

[www.aliexpress.com]

hope this will help, or if someone have an advise

Regards

Quote
LB-3D
Hi all
actually I am printing my new designed printer (TRUSS) with 550 mm actual bed print size
when searching I found this, and planning to order
its not in Europe as well but...

[www.aliexpress.com]

hope this will help, or if someone have an advise

Regards

Only thing I would point out is that there is no details on that item as to working Voltage and Wattage of the heater.

It looks like it may be 12V but who knows and at 500 mm diameter that will probably take an awful lot of current be careful It will certainly be more than a Ramps can handle my 300 x 300 mm katon heater draws about 22 amps at 12V.

Doug

Thanks Doug.
I contacted the supplier for full info and waiting for his reply
I will post once received
for powering i am planning to use automotive relay 30-40 amp to bypass my ramp
regards

Quote
LB-3D
Thanks Doug.
I contacted the supplier for full info and waiting for his reply
I will post once received
for powering i am planning to use automotive relay 30-40 amp to bypass my ramp
regards

I would not count on automotive relays. I had 60A relays go dead with repeated use at 10A and this was not a resistive load, 10A was spike 5A was continuous duty. Some are better than others, if your planing on a relay and a switch, you might as well save the costs and get a 30AMP rated switch. One more thing is that how do you plan on controlling the temperature? Planning on running the bed at max at all times? Do you have a thermostat capable of switching this heater? You may want to look at a solid state relay that you can control with the ramps.

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My Personal Blog. Build blog.
[engineerd3d.ddns.net]

Modicum V1 sold on e-bay user jaguarking11

For a 500mm diameter bed , I estimate you will need about 600W power. At these power levels, AC mains power is the most practical solution. So be sure to order a mains-voltage heater.

Fortunately, the fixed bed of a delta printer means that using mains power to heat the bed is safer than when the bed is moving. Nevertheless, you need to have adequate insulation and sound protective grounding of the bed and other metal parts of the printer. For added safety, use an RCD in the mains power feed to the printer.

You can switch AC mains power to a heater very easily using an inexpensive zero-crossing SSR.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].