Bed sticking. Pretty frustrated.

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Stephen Johnston

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Mar 9, 2018, 2:46:54 PM3/9/18
to Makerbot Users
Im a high school tech teacher. Our district bought 3 MB+ machines. (I would have opted for the Ultimakers. But it is what it is) Anyway, we are having LOTS of problems with builds sticking onto the bed. I tried blue tape. Worked then it didn't. I put down Krylon tape strips. It worked then it didn't. I sprayed hairspray on it. That did not work either.  My students and I are TOTALLY at our wits end dealing with this. 
 We want something that works every time. But we have not found it.
 I understand the heated bed option. But money is an issue also. And with the summer coming up that could be a possibility. But with 3 units thats pricy.
So Im just wondering if anyone has any suggestion that will work. 
Thanks



Malek Kabariti

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Mar 9, 2018, 3:24:02 PM3/9/18
to Stephen Johnston, Makerbot Users
Hi Stephen

The best Build surface I used is the EZ-Stik 3D Printer Build Surface "I had a lot of problems with Build surfaces", From https://www.geckotek.co/, it works with PLA, ABS, Nylon and other filaments.  

Regards

Malek


--
Malek Kabariti

Former Minister of Energy and Mineral Resources (MEMR).
The Hashemite Kingdom of Jordan.

Former Chairman of the National Electric Power Co (NEPCO).
The Hashemite Kingdom of Jordan.

Former President of the National Energy Research Center (NERC).
The Hashemite Kingdom of Jordan.

Former Director of the Renewable Energy Research Center (RERC) - The Royal Scientific Society (RSS).
The Hashemite Kingdom of Jordan.


Mob. +962 79 90 500 80
P.O.Box 5211
Amman 11183 JORDAN

malek.k...@gmail.com

 
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Rich Webb

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Mar 9, 2018, 3:28:02 PM3/9/18
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On the blue tape, ensure that you give it a rub with isopropyl alchohol before printing. That removes the interlayer wax on the top surface which keeps it from sticking to itself (too much) on the roll, helps to lift the nap a little to give the plastic something to grab onto, and removes smudges/fingerprints/etc between prints.

How confident are you that your first layer height is good? The best method I've found for leveling/tramming is purely empirical, by printing a single layer test print. I like using the three-lobed test here, oriented with the lobes over each leveling screw (more or less) and printed using concentric infill. That lets me tweak the nozzle to bed distance and get real-time feedback as the path loops around successive perimeters. An ideal print is a solid sheet where the tracks have merged so that it resists being torn apart (no "Venetian blind" effect) but not so "squished" that there is excessive bacon-patterning.

Eric Pavey

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Mar 11, 2018, 5:28:55 PM3/11/18
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I used to have a rep1: I made it a simple removable glass bed for it held down with clips. That with purple glue sick on top (not white) worked great. Goodbye kapton, goodbye blue tape.

Stephen Johnston

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Mar 12, 2018, 9:09:53 AM3/12/18
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EP
Saw your response. Thanks. I to have bought a glass bed for that. But, question. How did you work the leveling with that glass plate. If you put on the plate that plate is higher than the standard bed and that 'home' position hole on the MB+ is below that glass. Im scared when it goes through the leveling process it will hit that glass???

Jetguy

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Mar 12, 2018, 10:15:24 AM3/12/18
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The leveling sequence is made when the nozzle hits the bed surface. It doesn't matter what it hits, glass, metal, plastic print surface. This is a classic case of not understanding the different models of makerbot and how they function. Yes, OLDER printers before the 5th generation series used a mechanical limit switch attached to the frame of the printer and hit by the mechanical Z stage moving up and down. The bed and whatever surface was on it had adjustable threaded posts and nuts that the user adjusted to move the bed surface in relation to the underlying mechanical Z stage frame. 5th generation machines DO NOT have limit switches anywhere on the frame.

"when it goes through the leveling process it will hit that glass???" Answer, YES, it will hit the glass- intentionally because that's how it properly works in this series of printer.
This is a function of the MakerBot 5th generation printers including the newer plus.
The smart extruder nozzle can move and is spring loaded to the down position. When your print starts, the printer raises the bed surface until the nozzle hits the little metal inserts in the stock plastic bed surface. The Smart extruder internally senses when that nozzle is pushed up by the bed contact. The idea was that the little metal inserts in the stock bed are level or very near level with the plastic print surface. When you add a glass plate to 5th generation printer now the hard glass surface IS the same point the nozzle hits. The main reason for the metal inserts was to keep the hot nozzle from melting a hole in the same spot of the stock plastic surface. Further, the previous model of 5th gen printer came from the factory with a glass bed surface and STILL used the same basic smart extruder Z homing method.

What you may have to adjust is the Z axis homing offset. That value is what determines the nozzle height for first layer will be compared to the touch point sensed during the homing sequence. https://support.makerbot.com/learn/makerbot-replicatorplus/printer-tips/adjusting-the-z-axis-offset_13544

Jetguy

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Mar 12, 2018, 10:22:50 AM3/12/18
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Again, the nozzle is ALWAYS going to hit the surface during homing and leveling sequence on the 5th generation series by design. It is not a hard strike, the nozzle is spring loaded. This is simply how this printer homes Z axis. When the factory 5th Gen Plus plastic removable build surface is used, it has metal inserts in key touch point locations to prevent the nozzle from simply melting into the plastic during this normal process that happens every print. If you use a different surface like glass that can take a hot nozzle lightly kissing it without damage- no need for concern or alarm.

The nozzle offset is how far above or below this first sensed hit or contact at the start of the print the nozzle is then moved to for the first layer of the print.
This value matters no matter what surface you have. This is because again, this value determines where the nozzle will be AFTER the probing/homing sequence. If you get this value wrong, you can scrape the plastic bed or the glass bed the same regardless. At the same time, if this value is wrong and results in the nozzle too high on first layer- the print will not stick to ANY surface (glass or stock).
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