Printer commissioning - setting x and y zero points

Discussion in 'Build Help' started by John, Apr 21, 2016.

  1. John

    John Member

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    During the printer commissioning process, every time I set my x and y positions to zero, when I select the autohome it stops at 20,30 (x,y) and says it is at 5,5. This then sets the 0,0 position at 15,25 on the table.

    I always set my home offsets and save settings.

    Is it something to do with the home offsets? It was is defaulting to x=5mm and y=5mm.

    Also, on the front display, what does FR 100% mean (the value changes when I turn the knob)
    Thanks
    John
     
  2. Rob Heinzonly

    Rob Heinzonly Well-Known Member

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    FR100% is the FeedRate of the filament (this can be adjusted during printing).
    As for the Autohome:
    • Do you have a dual or Pro ?
    • Did you check the connectors on the endstop pins of the Rumba (they should be at the Y-min and X-min) ?
    • Did you check the wiring of the Y and X-axis motors (maybe you have switched them) ?
     
  3. John

    John Member

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    It is a dual
    I selected 'Restor Failsafe' and it seems to be OK now with an autohome in the right position. I'm continuing with the first print without success now. Ugh!!! Getting close to binning it.
     
  4. Henry feldman

    Henry feldman Well-Known Member

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    If homing is correct, what is failing now?
     
  5. John

    John Member

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    I am trying to print the 3dbenchy.gcode and apart from not sticking to table issues, very poor quality print problems which I should be able to work out through trial and error, I always get the thermal runaway after about 5 mins of the print. I can see the temp dropping at a rate which is clearly normal cooling (ie heater has stopped working).

    I don't understand issues like:
    - Should auto temp be on or off. If on, what tolerances should I set. Is this causing the issue. I've tries different settings but nothing seemed to change.
    - What are PID setting on the display- is this causing the heater to turn off
    - What is the Fan speed on the display - I adjust it and after a while the print program seems to override it and the fan goes to a different value while printing no matter what the settings are.

    I have googled PID settings and looked in the forum but nothing is clear on this. I played around with some settings but nothing changed.
    Apparenty I need to run a config program to get these but I have no idea how to do this. I presume I need to set up an interface, or can I put a config file on the SD card through the LCD display unit and somehow run it from there?

    I am also confused on the filament specs. The filament supplied was loose so I don't know what is is. I have purchased a roll. On the packet it say min temp hot end is 260. On the web, everywhere it says it is around 220 for ABS. I tried different settings and the only partial success was using high temps and high table temp (280 and 120). I then get thermal runaway issues.

    Ive tried to print maybe 50 times with all sorts of settings but I end up with bits (either not sticking or the first few mm of the boat with very poor quality). Slowing down the print doesn't seem to help with the thermal issue.

    Sorry to be such a problem.
     
  6. Spoon Unit

    Spoon Unit Well-Known Member

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    The 3dbenchy.gcode file supplied from e3d has a number of issues for the first time printer and I think you would be better off re-slicing it yourself.

    For your first print, don't use ABS - you're just creating a world of pain for yourself right from the start. The supplied samples that came with your BB are all PLA. They print well between 195 (matt finish) and 215 (more glossy). You can try temps inbetween. You're going to have a much easier time with this.

    But let's start from the top, or the bottom rather.

    Layer 1 is the most important layer of any print. If it's not right, you might as well stop the print straight away. The quality of the first layer is mostly a function of having the machine understand how level the bed is. Run through the bed leveling from the LCD. You can either eyeball this process or use a piece of paper. I recommend you start with a piece of paper. Once the nozzle is above the first point in the bed levelling process put a piece of paper under the nozzle and lower it using the job wheel until it touches the paper. You want to be able to move the piece of paper under the nozzle at it's lowest point, but only just. This is a "feel" area that you'll get more of a feel for over time. Repeat for all bed leveling points. Once complete, make sure you save those settings.

    Set your print running. If you're still with the supplied benchy, you're going to have to nurse it for at least the first 10 layers of the print and you'll need to be fast on the LCD. I really recommend re-slicing it, but if you have to go with the supplied one, get ready. Watch that first layer print. Better still, take some pictures of that first layer printing and post them here. Ideally, the lettering on the base should be quite readable. As it fills in around the print, it should like a little messed up, but not too much (again a feel thing). The reason for the mush is that layer 1 is printed at something like 70% of the height it should be in that supplied gcode. This is a good tactic to get a solid first layer, but it will result in slightly mushed up lettering and first layer. Layer 2 should look a bit smoother. Now layer 3 is where the cooling fan starts on that supplied gcode. It's going to come on at 30%. Probably not a problem. Let that layer print, but while it does, go into the LCD under Control > Temperature, and note the Fan number. By now layer 4 is probably started and the part cooling fan is up to 40%. The hotend hasn't had time yet to fully re-level from the 30% fan change to the thermal situation so 40% is a new challenge. Probably it's all OK still, but it's just going to get worse. Layer 5 has the fan at 50% and layer 6 at 60% and probably with your first time setup you're going to fail here at layer 6. The hotend just doesn't have time to respond and the cooling beats the heating. In other words, the thermal situation is running away out of control. The hotend is more than 20 degrees colder than it should be. Marlin believes it's out of control (it is) and shuts down. So what you've got to do is keep adjusting that fan. I suggest when you get to layer 5 and through layer 10, you keep knocking the fan back down (using the LCD) to where it was at 40%. After you fix that on layer 10, move it up to 50%. Now wait to about layer 16 and move it to 60%. That's probably enough for print number one. Everything should print out fine now.
     
  7. Alex Stevenson

    Alex Stevenson Well-Known Member

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    Our of curiosity, is there an updated benchy available for download anywhere? I'll be likely in the same "boat" when my order of filament arrives next week (damn you all for being prompt in ordering yours! :p - Everyday filament is currently out of stock). In the meantime, I may try to update the original code, and would be useful to compare the two...
     
    #7 Alex Stevenson, Apr 26, 2016
    Last edited: Apr 26, 2016
  8. John

    John Member

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    Thanks for the information. I have levelled the table several times as described so i think the extruder height and table is ok. Ill definitely change the filament to make it easier. Looks like i need to find another model to print.

    I still would like to understand what settings my Pid values should be and whether I should have auto temp on or off. Are these values of no consequence at this stage of my understanding to get my first print out.

    Under temp control on the display, i can manage the fan speed, but what does the value relate to. Is it % of max speed. Ie what unit is fan speed on the display? I'm not in front of the printer at present but i dont think i can id a fan number as suggeted. Might be wrong on his one.

    I can't grasp the concept of setting the fan speed if something else s controlling the fan and i have to fight it to successfully create a print. The default setting is 0, but the fan cuts in at a set temp. If i change the fan setting while printing, doesnt the software change this according to parametrs fed back to it. Why doesnt the contoller and preset parameters manage fan speed. Im very confused.
     
  9. Spoon Unit

    Spoon Unit Well-Known Member

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    The fan value is a number between 0 (0%) and 255 (100%).

    You definitely won't want to sit and control the fan all the time. You can define a less aggressive cooling strategy using S3D.

    There are two types of fan. Heatsink fans (they're on 100% from the moment a nozzle hits 40C and you don'.t need to worry about it. Then there's the part cooling fan which is completely controlled by the gcode. This is what's killing your print; that specific gcode.
    The reason you have to keep faffing with the fan right now is the gcode supplied. It's constantly changing the part cooling fan speed ever layer from layer 3 to 10. So if you change it manually, your setting is overridden by the next command in the gcode. Again, the solution is to slice it with a less aggressive cooling strategy.

    PID - You can't tune this from the LCD. You need octoprint or some other terminal input device. If you have that, look up PID tuning on the forum, I did a detailed post on this and I think others have too.
     
  10. Spoon Unit

    Spoon Unit Well-Known Member

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    @Alex Stevenson. There's nothing wrong per se. with the gcode supplied. It will work on a printed set up in a certain way. Remember that the e3d print farm was built by people who are long in the tooth at building machines. They're in the unconsciously competent category. They've forgotten more about 3d printing than I'll probably ever know. As a printer-building novice, I had my part cooling fans way too high initially. I still question whether that change alone would have fixed things.

    The best advice I can give you is to get to grips with S3D, or whatever slicer you want to use, and recut the benchy stl with a less crazy cooling strategy.

    As an aside, those who are in the pre-order category will receive a Hybrid print head with a single part-cooling fan. That cuts the colling issue in half and people like @PsyVision have reported that they've printed the delivered benchy.gcode with no problems on that setup, so maybe you'll nevcer encounter this challenge anyway. In a way, that's a shame, as it's good to know about how to control the fan to your needs.
     
  11. Alex Stevenson

    Alex Stevenson Well-Known Member

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    Thank you. I'm actually going through the settings now, and can see them in the FFF settings > Advanced > Cooling and using the BigBox Pro profile, although I re-downloaded the benchy from the website, rather than the SD card. I'll try modifying it from here, and see how it goes.

    @John I sincerely hope you get a successful print soon - it's indeed quite an anxious time until that first successful print is complete.
     
  12. Henry feldman

    Henry feldman Well-Known Member

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    The fighting the cooling is ONLY for the SD card supplied benchy. You won't do that again. You are correct that it will keep fighting you for a while (you can see how many times it sets the cooling) but after it stops changing it will stop fighting you. Just set your own cooling in your slicer (S3D) replace the model, and you will have success, and I have never needed >40% on anything (anything more and you risk runaway). Now as you get higher in temp (ABS, Bluprint, nylon, etc) you have even a harder fight. I have found with Bluprint I am running max 10-15% or I get runaway.
     
  13. Spoon Unit

    Spoon Unit Well-Known Member

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    @Henry feldman , what temp are you printing Blueprint at? I noticed the same regarding the difficulty of keeping temp with higher nozzle temps. I've ordered some Kapton tape to try out around the hotend to insulate it from the gale.
     
  14. Henry feldman

    Henry feldman Well-Known Member

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    265C
     
  15. Henry feldman

    Henry feldman Well-Known Member

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    Oh, and the weird thing is IIR that Kapton actually has a fairly high thermal conductivity...
     
  16. Sarah Nicholson

    Sarah Nicholson Well-Known Member

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    Spoon Unit and Alex Stevenson like this.
  17. Henry feldman

    Henry feldman Well-Known Member

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  18. mike01hu

    mike01hu Well-Known Member

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    Once again, this solution uses a silicone moulding and that will create issues for high temperature filaments, such as your Peek Henry, so there has to be another solution. I favour wrapping the heated block with glass fabric tape but will wait to try it when I get to that stage. The Kapton wrap is primarily a protection from direct air cooling and it is usually several layers, so its own thermal conductivity is less of an issue but I don't know how this would perform at 400C.
     
    #18 mike01hu, Apr 27, 2016
    Last edited: Apr 27, 2016
  19. Spoon Unit

    Spoon Unit Well-Known Member

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    @Sarah Nicholson thanks for that link. Interestingly there's also a design file connected with the start of that post and indication that Sugru (which I do have) could be used to create an insulation jacket. Could be fun to try that. The only thing there is that apparently after 180C Sugru loses some of its mechanical qualities and could become brittle. I worry that could mean it disintegrating. I think i'll look into that though. I'll definitely buy some little silicone insulators from e3d as and when they sell this item.

    Actually that link took some time to re-find, so here it is:

     
    #19 Spoon Unit, Apr 27, 2016
    Last edited: Apr 27, 2016

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