Yes, I used the exact anti-backlash nut on my UM2 which has the same heated bed. But I had to dismount the black part of the nut and mount the UM2 nut instead. And a printed adapter piece was needed.
So, you stuck with it? The modification and adapter were just means to mount it?
Did you notice any difference in print quality?
I'm building/sourcing one now too. Impressed with the leveling system! Got to install it in the printer still though.
Is it possible to run it without the heated bed/electronics connected, just having the platform for now?
I'm building/sourcing one now too. Impressed with the leveling system! Got to install it in the printer still though.Is it possible to run it without the heated bed/electronics connected, just having the platform for now?
Absolutely.
As far as I can see, you would just need to change the steps value for Z to match the new lead screw and install/adjust the new limit switch.
Yes, I used the exact anti-backlash nut on my UM2 which has the same heated bed. But I had to dismount the black part of the nut and mount the UM2 nut instead. And a printed adapter piece was needed.
So, you stuck with it? The modification and adapter were just means to mount it?
Did you notice any difference in print quality?
It's still in, yes. Difficult to say if print quality improved. I had an issue at that time which ruined the print quality (horizontal banding caused by the bang-bang mode of the heated bed). However, mounting the anti-backlash nut did not solve the issue. After the issue was solved I left the anti-backlash nut in. Quality is - hm - just perfect, as usual on my UM2... 
The modification and the adapter were necessary as I didn't want to drill any holes into the aluminum plate.
Edited by Guest
1
There is definitely a decent amount of backlash in the lead screw.
Yes, you have gravity working to help take up backlash, but giving it a bit of help is good insurance against forces that would exploit the backlash, like the linear bearings sticking on reversal (which mine do).
Some questions:
- I know that the latest Cura has a compatible firmware build, but was wondering if using this builder would be equivalent: http://marlinbuilder.robotfuzz.com/
I have a few other tweaks; custom extruder drive, direct drive XY, and a bunch of custom parameters for accel, jerk, etc.
- Is there a way to make a dump of my current firmware as a backup?
Anyone?
Edited by Guestrobotfuzz is incompatible with the pt100 found in the heated bed. However you can use this marlin builder:
Unfortunately it has MANY fewer options :(
To make a dump of your current firmware you need to know what version it is. I don't remember if you can determine it on the ulticontroller. You basically have to know where the hex file is that created it. You can get tons of old firmware versions from all the old curas here:
robotfuzz is incompatible with the pt100 found in the heated bed. However you can use this marlin builder:Unfortunately it has MANY fewer options :(
To make a dump of your current firmware you need to know what version it is. I don't remember if you can determine it on the ulticontroller. You basically have to know where the hex file is that created it. You can get tons of old firmware versions from all the old curas here:
Thanks gr5!
Unfortunately, I just found that out on my own 
The control gave me a max bed temp error and showed the wrong idle temp.
I flashed the stock firmware via Cura, and everything looks good, bed heats... I just can't use it because of my direct drive.
How does that builder compare to the official firmware base? Would I be better off editing the official? It's been forever since I compiled a firmware build and remember very little.
Maybe you could also help me better understand adding the files to the Arduino environment.
Install the arduino software IDE/toolset v23 (Some configurations also work with 1.x.x) http://www.arduino.cc/en/Main/SoftwareDownload the Marlin firmware https://github.com/ErikZalm/Marlin/tree/Marlin_v1 Use the "Download Zip" button on the right.
For gen6/gen7 and sanguinololu the Sanguino directory in the Marlin dir needs to be copied to the arduino environment. copy ArduinoAddons\Arduino_x.x.x\sanguino \hardware\Sanguino
Start the arduino IDE. Select Tools -> Board -> Arduino Mega 2560 or your microcontroller Select the correct serial port in Tools ->Serial Port Open Marlin.pde
It just says copy the files. Copy them where?
I have this similar folder: Program Files (x86)\Arduino\hardware\arduino\avr
But copying the files there would overwrite boards.txt
It's a little more clear in the readme:
For gen6/gen7 and sanguinololu the Sanguino directory in the Marlin dir needs to be copied to the arduino environment.copy ArduinoAddons\Arduino_x.x.x\sanguino \hardware\Sanguino
- I know that the latest Cura has a compatible firmware build, but was wondering if using this builder would be equivalent: http://marlinbuilder.robotfuzz.com/
I have a few other tweaks; custom extruder drive, direct drive XY, and a bunch of custom parameters for accel, jerk, etc.
The best thing you maybe can do is to download the UMO HBK Marlin version from the Github repository and modifiy the configuration.h file with your tweaks. Then you can directly build and upload the firmware with the Arduino Software. In order to find out how you have to modify the configuration.h file you can download the zip file of your current configuration from Robotfuzz-Marlinbuilder which also includes a configuration.h file. But you cannot use this file directly out of the same reasons you already figured out.
If you are working with Windows I can recommend Winmerge for comparing the two configuration.h files and move information/settings from one to the other.
Edited by Guest
2
- I know that the latest Cura has a compatible firmware build, but was wondering if using this builder would be equivalent: http://marlinbuilder.robotfuzz.com/
I have a few other tweaks; custom extruder drive, direct drive XY, and a bunch of custom parameters for accel, jerk, etc.
The best thing you maybe can do is to download the UMO HBK Marlin version from the Github repository and modifiy the configuration.h file with your tweaks. Then you can directly build and upload the firmware with the Arduino Software. In order to find out how you have to modify the configuration.h file you can download the zip file of your current configuration from Robotfuzz-Marlinbuilder which also includes a configuration.h file. But you cannot use this file directly out of the same reasons you already figured out.
If you are working with Windows I can recommend Winmerge for comparing the two configuration.h files and move information/settings from one to the other.
Agreed. I went ahead last night and modified the new official release. It's really not bad at all, thanks to the write-ups by members of our community. Thanks GR5!
I tried to do a PID autotune on my bed last night and ran into two issues. First was a timeout. It was definitely heating, but seemed to struggle to hit the commanded 90* from ambient. I immediately restarted the processes and it seemed to be working.
Then I decided that I wanted to preheat the nozzle while that was happening, so on the UC, I turned it on. The set point showed up but the nozzle didn't begin to heat, seemingly from a conflict with Pronterface having control. The Bed autotune continued for a couple minutes, but then gave me a heating failed error, which also showed up on the UC display. Not sure if that was my fault.
Also, during the autotune, the bed temp display in pronterface didn't update in realtime like it has with the nozzle in the past. Not sure why.
Man, I forgot how aggressive the stock XY accel settings are! The Z accel of 100 is pretty soft though, and 300 has worked well so far.
I've never tried to autotune the bed. In bang-bang mode (P=infinite I=0 D=0) it keeps a very steady temperature. But some people reported problems with bang-bang mode where their nozzle (go figure?) changed temp too much. So I recommend you stick with PID mode for the bed and not alter the existing PID values. They work fine.
My bed can get up to 100C in a 20C room but has trouble getting to 110C. Sometimes it never quite reaches 110C. If I put a box over the top and cover the front then it can get to 110C no problem (and the ambient air inside is around 50-60C).
There two different gcodes to change the bed temp - one is "do it and return now" and the other is "do it and don't accept more gcodes until you reach the temp". Possibly pronterface used the wrong gcode? It seems unlikely and I *thought* I've messed with bed temp and nozzle temp at the same time with pronterface but I'm not sure.
My bed is holding a steady temp, so I'm not too concerned about running autotune now. It sure takes a while to hit 90* though!
Probably the biggest shortcoming I've found so far is the bed platform's bending stiffness. 4mm aluminum plate cantilevered out 12" just isn't up to my standard for stiffness.
Luckily, it's a pretty easy modification with the way it is designed.
I'm thinking about mounting two pieces of aluminum angle stock on the underside, so that it spans from a front corner, to the inside edge of a linear bearing. This will really improve the stiffness.
http://www.mcmaster.com/#8982k91/=x6puu3
Edited by GuestI'm not sure that there is a problem. The bed holds it's position for months of printing without needing re-leveling even though sometimes I have to wack the parts off the bed using my palm as a hammer and a putty knife to apply the pressure with enough force to slide the printer a foot across the table.
I'm not sure that there is a problem. The bed holds it's position for months of printing without needing re-leveling even though sometimes I have to wack the parts off the bed using my palm as a hammer and a putty knife to apply the pressure with enough force to slide the printer a foot across the table.
So, you are describing the repeatability of the leveling system / support springs. The 4mm platform is the base for that, so yes, it can stand up to a beating without plastically deforming, but that doesn't speak to its dynamic stability.
When we are trying to print say a 0.1mm layer height, how much of a deviation in Z height of the nozzle do you think it takes to either swell or contract the width of the bead you are laying down? I would guess that even a 25% change would produce a visible artifact. That is only 25 microns, or around 0.001" for us yanks.
Not only do you have an interaction between the nozzle/filament bead and the part/bed which can cause movement, or excite vibrations, but also the rapid changes in Z height from layer change or Z hop moves. To a lessor extent, you even have the printed part's weight increasing throughout the print, and adding to deflection of the bed.
The temptation is to print right at the front of the bed, in the middle... which is literally the worst place to print for machine rigidity. The best bet would be at either back corner, where deflection of the bed, lash from the Z bearings, and flex of the 8mm and 6mm rods is minimized.
Here is a quick video to illustrate specifically the cantilevered deflection of the bed platform. I'll check again after my modifications sometime next week. (I'm going to the RAPID conference in LA early next week, woohoo!!)
I decided to whip up a Solidworks static simulation to illustrate the concept. I used the STP file for the build platform from the Github repository and applied 6061-T6 as the material.
Here is the intended modification. Twin .75"x.75" aluminum angle, bolted to the underside:
For the simulation, I simply fixed the linear bearing mounting features ( a simplification, but a good representation), applied gravity, and applied a 1lb point force near the front of the bed.
Here are the displacement charts with a 50x exaggeration and equal color scaling:
Original:
Braced:
The braces reduce deflection by nearly 90% in this situation. Are these numbers directly applicable to printing? No. Is a stiffer platform going to give you more consistent prints? Yes.
Here's a quick video I shot in super slow mo, that shows the judder in the bed during a layer change:
1
I wonder, if this seems to be a problem, why UM2 users havn't reported this
To me it seems more like the bottom of the nozzle going over the print of the plastic itself... Sometimes with a lot of retractions etc it creates "hills" on top of the print that are a bit higher than where the head is positioned at. If it moves over it bounces the bed up and down.
I'd have to hear the actual sound being made to compare it to what I've experienced a multitude of times, but it sure looks the same visually.
There was a conversation a while ago where someone was complaining about how its canter-levered out and not rigid enough then someone from Ultimaker R&D mentioned that they tried having it supported from both ends but the quality was worse.
But it agree with Blizz, it tends to only judder while going over bits like curling and "hills"
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Dim3nsioneer 557
Yes, I used the exact anti-backlash nut on my UM2 which has the same heated bed. But I had to dismount the black part of the nut and mount the UM2 nut instead. And a printed adapter piece was needed.
Edited by GuestLink to post
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