A couple of questions on The new Modular bed system

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piercet
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A couple of questions on The new Modular bed system

Post by piercet » Sun Nov 26, 2017 10:49 pm

Looking at the new product listings, it looks like you will have a new modular bed setup for the Taz out soon, and I have a few questions about it if anyone has a moment to answer them.

1. Does the new setup weigh more than the current stock setup, and if so, how much more?
2. Does the spring steel plate offer additional stiffness to the bed (specifically does it add enough strength that you can go with a thinner than current stock plate over the top of it to reduce mass?
3. Any plans to try an aluminum core bed out any time soon?

Thank you!

Brent.I
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Re: A couple of questions on The new Modular bed system

Post by Brent.I » Mon Nov 27, 2017 8:32 am

The new setup does weigh more.

Original TAZ Heat Bed Assembly with PEI: 881.5g

Modular TAZ assembly with glass and PEI: 1429.2g

Glass and PEI alone: 694.8g

The spring steel really helps with heat diffusion, giving a very even heat surface. You can find some thermal images and testing data here: http://devel.lulzbot.com/TAZ/accessories/zebra/

We have seen that the spring steel will slightly bow when heated, and the thicker borosilicate glass helps keep the bed flatter. If you would like to experiment with different surface coverings (or materials) you may just need to adjust the corner pieces and stand offs for a tight fit.

We are currently working with Tempco to explore different materials, but nothing concrete yet. I believe aluminum is included in those discussions...

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Re: A couple of questions on The new Modular bed system

Post by piercet » Mon Nov 27, 2017 2:58 pm

Cool! If you want ideas for materials to test out, here's what I would like to see

1. A 3/16" thick copper plate with PEI or buildtak on top
2. a 3/16" thick aluminum plate for comparison
3. a Graphite plate (not carbon fiber, which is more of an insulator)
4. A plate made up of a mix of industrial diamond powder and PEI resin.

Since glass is an insulator and copper and aluminum are the best available heat conductive metals around I would expect them to perform well. Graphite and diamod powder are both theoretically 5 times more heat conductive, but may have other issues with obtainability and reliability that might make them poor choices.

I'm running a 3/16" thick aluminum plate currently, I'm thinking about switching to a copper plate if I can find a flat one.

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Re: A couple of questions on The new Modular bed system

Post by kcchen_00 » Mon Nov 27, 2017 10:16 pm

I've been jealous of that aluminum bed since you (piercet) put it in. This modular system seems like the ticket to get on the bandwagon.

Bed system seems pretty heavy, but I like the idea of the modular glass & PEI plates.

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Re: A couple of questions on The new Modular bed system

Post by nuroo » Fri Dec 08, 2017 12:01 pm

More weight/mass for belts, motors = more back lash? More ringing/ ghosting?

How fast can we print without getting ghosting with new modular print bed system?

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Re: A couple of questions on The new Modular bed system

Post by piercet » Fri Dec 08, 2017 1:56 pm

nuroo wrote:
Fri Dec 08, 2017 12:01 pm
More weight/mass for belts, motors = more back lash? More ringing/ ghosting?

How fast can we print without getting ghosting with new modular print bed system?
The answer is going to be "it depends" a lot of that has to do with the size of the object you are printing. A full bed capacity print is going to be much more affected by a heavy bed than a lighter one. I know you can get a stock taz bed on stock rails up near 90mm / sec without major issues, possibly higher. That assumes a very well tensioned belt and no bearing slop or play. Doubling the mass you should be able to still print quite fast, but you might have to drop 20-30mm/s. You can compensate for that by adding belt tensioners or rail systems or hardened rods, higher torque motors, etc. And nothing says you have to stay with glass (which is heavy and an insulator) as the upper deck. I'd bet that spring steel plate actually might offer a not insignificant amount of structure, so you might be able to put a less than 3/16" thick Aluminum plate with PEI on top on it and still get the same support at a lower weight with drastically improved thermal characteristics.

Typically more mass on a moving bed can effect things like infil (more blobbing on the ends during a diagonal pattern because the bed takes more time to stop and go the other way) ringing occasionally (more bounce on the rods during movement) and possibly more of what looks like Z wobble but is actually side to side rod sway. All of that can be compensated for, and the ability to try other top materials makes it intriguing even with the added weight.

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